# data[].attributes.attachment_link.readable_text
Before 1973

Polar bears are an integral part of the Arctic ecosystem and the food web for Indigenous Peoples - who have hunted polar bears sustainably for millennia. But, beginning in the 1700s, large-scale hunting by European, Russian and North American hunters and trappers took place, raising concerns about the future survival of polar bears. Unregulated commercial and recreational hunting continued until the 1970s.

1973

Canada, the United States, Denmark, Norway and the former USSR signed the International Agreement on the Conservation of Polar Bears and their Habitat, strictly regulating commercial hunting.

The US Government classified the Polar Bear under its Endangered Species Act (ESA).
2005
The polar bear was upgraded from Least Concern to Vulnerable by the the IUCN Polar Bear Specialist Group.
2013
Ministers and other leaders from the five polar bear range states met in Moscow for the first International Forum on Polar Bear Conservation. The leaders made significant commitments to address issues of polar bear habitat, research and trade. This event was supported by WWF.

Today

Today, polar bears are among the few large carnivores that are still found in roughly their original habitat and range-and in some places, in roughly their natural numbers.

Although most of the world's 19 populations have returned to healthy numbers, there are differences between them. Some are stable, some seem to be increasing, and some are decreasing due to various pressures.

Status of the polar bear populations
Updated 2021 with data from the IUCN Polar Bear Specialists Group:

3 populations are in decline
2 populations are increasing
4 populations are stable
10 populations are data-deficient (information missing or outdated)

In the future

By 2040, scientists predict that only a fringe of ice will remain in Northeast Canada and Northern Greenland when all other large areas of summer ice are gone. This "Last Ice Area" is likely to become important for polar bears and other life that depends on ice.

A projection of sea ice in the archipelago, supported by WWF, shows that much of the region is facing significant ice loss in the coming decades - with potentially serious consequences for polar bears.
Global polar bear numbers are projected to decline by 30% by 2050.

# data[].attributes.attachment_link.description
How many polar bears are there? See current polar bear populations, IUCN Red List status by country and timeline of polar bear conservation.

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[인사이트] 전형주 기자 = 1960년 5000마리까지 줄었던 북극곰의 개체 수가 다시 증가세를 보이고 있다.

최근 미국 과학지 폴라 베어 사이언스는 글로벌 환경단체 세계자연기금(WWF)의 조사 결과를 인용해 "북극곰의 개체 수가 4만 마리까지 증가했다"고 보도했다.

보도에 따르면 지난해 북극곰의 개체 수는 총 3만9천여마리까지 늘어났다. 추정치지만 멸종위기종을 살리려는 노력이 빛을 발했다는 평가가 나온다.

북극곰은 캐나다의 북서부와 알래스카 동부를 비롯해 총 19곳에 번식하는 것으로 알려졌다. 이 중 개체 수를 확인할 수 없는 9곳을 제외하고 나머지 9곳은 전부 안정적으로 늘었다.

멸종위기종인 북극곰의 개체 수는 지구 온난화의 영향으로 꾸준히 감소했다. 1985년에는 잠시 반등했으나 주춤주춤하며 다시 감소세로 돌아섰다.

하지만 북극곰을 보호하려는 노력은 계속됐다. 북극의 면적이 지속해서 줄어들자 사람들은 일부 북극곰을 비슷한 환경의 새로운 서식지로 옮겨줬다.

이런 노력에 힘입어 북극곰의 개체 수는 50년 만에 세배나 늘어 관측 사상 최대치를 기록했다. 3만여마리를 넘어선 적은 관측 이래 단 한 번도 없었다.

같은 기간 주로 북극곰을 사냥해 생계를 유지하던 에스키모 수가 급감한 영향도 크게 작용했다.

다만 캐나다 북서부에서는 여전히 북극곰의 개체 수가 감소세였다. 이 지역에서는 해마다 600여마리의 북극곰이 사냥을 당해 죽어 나간다.

지구 온난화를 해결하기 위한 노력과 별개로 멸종위기종에 대한 사냥을 자제해야 한다는 지적이 나오는 이유다.

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멸종위기 북극곰 개체 수 ‘3배’나 늘어났다

# data[].attributes.attachment_link.title
멸종위기 북극곰 개체 수 '3배'나 늘어났다

# data[].attributes.attachment_link.description
인사이트] 전형주 기자 = 1960년 5000마리까지 줄었던 북극곰의 개체 수가 다시 증가세를 보이고 있다. 최근 미국 과학지 폴라 베어 사이언스는 글로벌 환경단체 세계자연기금(WWF)의 조사 결과를 인용해 "북극곰의 개체 수가 4만 마리까지 증가했다"고 보도했다. 보도에 따르면 지난해 북극곰의 개체 수는 총 3만9천여마리까지 늘어났다. 추정치지만 멸종위기종을 살리려는 노력이 빛을 발했다는 평가가 나온다.

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https://www.greenpeace.org/korea/update/5973/blog-arctic-rescue-polar-bears-in-global-warming/#foot3
위 글을 보면 북극곰 개체 수가 10년 새 절반으로 줄었다는 말이 나와있다.

또한 만약 북극곰의 개체 수가 증가했다고 하더라도 결국엔 서식지인 빙하가 녹으면서 개체 수가 급감할 것이라고 생각한다.

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기후변화로 인해 지구온난화가 심각해진다고 하는데 지구온난화가 어떤 현상인지 먼저 쉽게 설명해보겠습니다.

지구온난화의 원인은 무엇인가요?

지구온난화는 태양의 복사에너지가 지구의 표면에서 반사되어 지구 밖으로 나갈 때 대기층에 온실가스가 다시 지표면으로 되돌아와 지구의 평균 온도가 상승하게 되는 현상을 말합니다.

<로마에서 진행된 북극곰 터전을 지키기 위한 퍼포먼스>

국제 학술지인 네이처(Nature)에 게재된 한 보고서는 기후변화로 인한 세계적인 재앙을 막기 위해서는 지구의 기온 상승을 2도 이하로 낮춰야 한다고 발표했습니다. 또한, 이 목표를 위해서 전 세계 화석 연료 대부분을 매장 상태로 남겨둬야 한다고 말하며, 지금까지 나온 연구보다도 더 자세한 근거를 제시했습니다. 이 보고서는 데일리 메일(Daily Mail), 가디언(Guardian), BBC 등 주요 외신에서 인용됐습니다.[WU1]

다행히 국제사회에서 지구온난화를 해결하려 노력을 하고 있답니다.

<지구온난화는 다양한 기후 재앙의 원인이 되기도 합니다>

지구 온도 상승 1.5℃ 제한 위한 국제적 약속인 파리협정이란?

지구 평균온도 상승 폭을 산업화 이전 대비 2℃ 이하로 유지하고, 더 나아가 온도 상승 폭을 1.5℃ 이하로 제한하기 위해 함께 노력하기 위한 국제적인 약속입니다.

각국은 온실가스 감축 목표를 스스로 정해 국제사회에 약속하고 이 목표를 실천해야 하며, 국제사회는 그 이행에 대해서 공동으로 검증하게 됩니다.[WU2]

파리협정은 2016년 제23차 기후변화당사국총회에서 195개국의 만장일치로 채택됐습니다. 최근 미국의 탈퇴 선언에도 불구하고, 여전히 세계 탄소 배출의 87%에 달하는 200여 개 국가가 협정을 이행중입니다.

세계 7위의 온실가스 배출국가인 한국은 2030년까지 전망치 대비 37%의 온실가스 감축을 목표로 온실가스 감축에 동참하고 있습니다.

지구온난화가 북극곰에 미치는 영향은?

북극곰의 터전이 지구온난화로 인해서 위기에 빠져 있다고 하는데 그 이유를 아시나요?

<기후변화로 위기에 빠진 북극곰을 지켜주세요!>

북극은 지구 전체의 기후 시스템을 조절하는데 필수적인 역할을 하고 있기 때문입니다. 북극 지역은 '북극 증폭(Arctic Amplification)'으로 알려진 현상으로 인해 지구의 다른 지역보다 두 배 이상의 속도로 온난화가 진행되고 있습니다.

'북극 증폭'이란 바닷물이 얼어서 생긴 얼음인 해빙이 물로 만들어진 얼음보다 더 빨리 녹아 생기는 현상입니다. 해빙의 감소가 빠르게 진행됨에 따라 알베도(빛에너지의 반사율)가 줄어 북극이 점점 더 따뜻해지고 있습니다.

따라서 해빙을 옮겨 다니며 사냥을 하는 북극곰에게 지구온난화는 바로 삶의 터전의 문제입니다. 북금곰들은 삶의 터전을 잃고 먹이를 찾을 수 없는 치명적인 위기를 맞게 됩니다.

지구온난화로 바다얼음이 사라지면서 북극곰(Polar Bear) 개체수는 지난 10년 새 절반 가까이 급감했습니다.[WU3]

이는 북극곰만의 문제가 아닌 우리 모두의 문제입니다. 지구온난화를 막고 탄소배출을 줄이기 위해서는 파리기후변화협정과 같은 국가 단위의 노력뿐 아니라, 우리 개인의 노력과 작은 실천이 반드시 필요합니다.
우리에겐 시간이 없습니다. 북극 보호구역 지정을 위해 지금 동참해주세요!

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기후변화로 인해 지구온난화가 심각해진다고 하는데 지구온난화가 어떤 현상인지 먼저 쉽게 설명해보겠습니다.

지구온난화의 원인은 무엇인가요?
지구온난화는 태양의 복사에너지가 지구의 표면에서 반사되어 지구 밖으로 나갈 때 대기층에 온실가스가 다시 지표면으로 되돌아와 지구의 평균 온도가 상승하게 되는 현상을 말합니다.
<로마에서 진행된 북극곰 터전을 지키기 위한 퍼포먼스>
국제 학술지인 네이처(nature)에 게재된 한 보고서는 기후변화로 인한 세계적인 재앙을 막기 위해서는 지구의 기온 상승을 2도 이하로 낮춰야 한다고 발표...

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위기에 빠진 북극곰 살리기, 지구온난화의 원인과 해결방안 - Greenpeace Korea | 그린피스

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기후변화로 인해 지구온난화가 심각해진다고 하는데 지구온난화가 어떤 현상인지 먼저 쉽게 설명해보겠습니다. 지구온난화는 태양의 복사에너지가 지구의 표면에서 반사되어 지구 밖으로 나갈 때 대기층에 온실가스가 다시 지표면으로 되돌아와 지구의 평균 온도가 상승하게 되는 현상을 말합니다. 국제 학술지인 네이처(Nature)에 게재된 한 보고서는 기후변화로 인한 세계적인 재앙을 막기 위해서는 지구의 기온 상승을 2도 이하로 낮춰야 한다고 발표했습니다.

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https://www.arcticwwf.org/wildlife/polar-bear/polar-bear-population/

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Before 1973

Polar bears are an integral part of the Arctic ecosystem and the food web for Indigenous Peoples - who have hunted polar bears sustainably for millennia. But, beginning in the 1700s, large-scale hunting by European, Russian and North American hunters and trappers took place, raising concerns about the future survival of polar bears. Unregulated commercial and recreational hunting continued until the 1970s.

1973

Canada, the United States, Denmark, Norway and the former USSR signed the International Agreement on the Conservation of Polar Bears and their Habitat, strictly regulating commercial hunting.

The US Government classified the Polar Bear under its Endangered Species Act (ESA).
2005
The polar bear was upgraded from Least Concern to Vulnerable by the the IUCN Polar Bear Specialist Group.
2013
Ministers and other leaders from the five polar bear range states met in Moscow for the first International Forum on Polar Bear Conservation. The leaders made significant commitments to address issues of polar bear habitat, research and trade. This event was supported by WWF.

Today

Today, polar bears are among the few large carnivores that are still found in roughly their original habitat and range-and in some places, in roughly their natural numbers.

Although most of the world's 19 populations have returned to healthy numbers, there are differences between them. Some are stable, some seem to be increasing, and some are decreasing due to various pressures.

Status of the polar bear populations
Updated 2021 with data from the IUCN Polar Bear Specialists Group:

3 populations are in decline
2 populations are increasing
4 populations are stable
10 populations are data-deficient (information missing or outdated)

In the future

By 2040, scientists predict that only a fringe of ice will remain in Northeast Canada and Northern Greenland when all other large areas of summer ice are gone. This "Last Ice Area" is likely to become important for polar bears and other life that depends on ice.

A projection of sea ice in the archipelago, supported by WWF, shows that much of the region is facing significant ice loss in the coming decades - with potentially serious consequences for polar bears.
Global polar bear numbers are projected to decline by 30% by 2050.

# data[].attributes.attachment_link.description
How many polar bears are there? See current polar bear populations, IUCN Red List status by country and timeline of polar bear conservation.

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https://www.newscientist.com/article/dn11656-climate-myths-polar-bear-numbers-are-increasing/

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위 파일에는 여러 가지의 인간이 이산화탄소를 많이 발생시켜 대기 중 열을 지구에 가둬버리는 온실효과가 극대화되어 지구 기온이 오른다는 증거가 있다.
http://www.climate.go.kr/home/09_monitoring/intro/co2_intro
위의 사이트에서도 그러한 점을 찾을 수 있다

http://www.climate.go.kr/home/09_monitoring/ghg/co2_global_trend
여기에는 연평균 이산화탄소 농도가 증가하는 그래프가 그려져 있다.

http://www.climate.go.kr/home/09_monitoring/ghg/co2_global
위 링크는 미항공우주국에서 제공한 그림이다.

https://m.dongascience.com/news.php?idx=50165
이산화탄소 농도가 2020년에 최고치를 찍었다는 기사도 있다.

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Before 1973

Polar bears are an integral part of the Arctic ecosystem and the food web for Indigenous Peoples - who have hunted polar bears sustainably for millennia. But, beginning in the 1700s, large-scale hunting by European, Russian and North American hunters and trappers took place, raising concerns about the future survival of polar bears. Unregulated commercial and recreational hunting continued until the 1970s.

1973

Canada, the United States, Denmark, Norway and the former USSR signed the International Agreement on the Conservation of Polar Bears and their Habitat, strictly regulating commercial hunting.

The US Government classified the Polar Bear under its Endangered Species Act (ESA).
2005
The polar bear was upgraded from Least Concern to Vulnerable by the the IUCN Polar Bear Specialist Group.
2013
Ministers and other leaders from the five polar bear range states met in Moscow for the first International Forum on Polar Bear Conservation. The leaders made significant commitments to address issues of polar bear habitat, research and trade. This event was supported by WWF.

Today

Today, polar bears are among the few large carnivores that are still found in roughly their original habitat and range-and in some places, in roughly their natural numbers.

Although most of the world's 19 populations have returned to healthy numbers, there are differences between them. Some are stable, some seem to be increasing, and some are decreasing due to various pressures.

Status of the polar bear populations
Updated 2021 with data from the IUCN Polar Bear Specialists Group:

3 populations are in decline
2 populations are increasing
4 populations are stable
10 populations are data-deficient (information missing or outdated)

In the future

By 2040, scientists predict that only a fringe of ice will remain in Northeast Canada and Northern Greenland when all other large areas of summer ice are gone. This "Last Ice Area" is likely to become important for polar bears and other life that depends on ice.

A projection of sea ice in the archipelago, supported by WWF, shows that much of the region is facing significant ice loss in the coming decades - with potentially serious consequences for polar bears.
Global polar bear numbers are projected to decline by 30% by 2050.

# data[].attributes.attachment_link.description
How many polar bears are there? See current polar bear populations, IUCN Red List status by country and timeline of polar bear conservation.

# data[].attributes.body
https://www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide

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Based on the annual report from NOAA's Global Monitoring Lab, global average atmospheric carbon dioxide was 417.06 parts per million ("ppm" for short) in 2022, setting a new record high. The increase between 2021 and 2022 was 2.13 ppm-the 11 th year in a row where the amount of carbon dioxide in the atmosphere increased by more than 2 ppm. At Mauna Loa Observatory in Hawaii, where the modern carbon dioxide record began in 1958, the annual average carbon dioxide in 2022 was 418.56.

Carbon dioxide concentrations are rising mostly because of the fossil fuels that people are burning for energy. Fossil fuels like coal and oil contain carbon that plants pulled out of the atmosphere through photosynthesis over many millions of years; we are returning that carbon to the atmosphere in just a few hundred. Since the middle of the 20 th century, annual emissions from burning fossil fuels have increased every decade, from close to 11 billion tons of carbon dioxide per year in the 1960s to an estimated 36.6 billion tons in 2022 according to the Global Carbon Budget 2022.

Carbon cycle experts estimate that natural "sinks"-processes that remove carbon from the atmosphere-on land and in the ocean absorbed the equivalent of about half of the carbon dioxide we emitted each year in the 2011-2020 decade. Because we put more carbon dioxide into the atmosphere than natural sinks can remove, the total amount of carbon dioxide in the atmosphere increases every year.

The more we overshoot what natural processes can remove in a given year, the faster the atmospheric concentration of carbon dioxide rises. In the 1960s, the global growth rate of atmospheric carbon dioxide was roughly 0.8± 0.1 ppm per year. Over the next half century, the annual growth rate tripled, reaching 2.4 ppm per year during the 2010s. The annual rate of increase in atmospheric carbon dioxide over the past 60 years is about 100 times faster than previous natural increases, such as those that occurred at the end of the last ice age 11,000-17,000 years ago.

Why carbon dioxide matters

Carbon dioxide is Earth's most important greenhouse gas: a gas that absorbs and radiates heat. Unlike oxygen or nitrogen (which make up most of our atmosphere), greenhouse gases absorb heat radiating from the Earth's surface and re-release it in all directions-including back toward Earth's surface. Without carbon dioxide, Earth's natural greenhouse effect would be too weak to keep the average global surface temperature above freezing. By adding more carbon dioxide to the atmosphere, people are supercharging the natural greenhouse effect, causing global temperature to rise. According to observations by the NOAA Global Monitoring Lab, in 2021 carbon dioxide alone was responsible for about two-thirds of the total heating influence of all human-produced greenhouse gases.

Another reason carbon dioxide is important in the Earth system is that it dissolves into the ocean like the fizz in a can of soda. It reacts with water molecules, producing carbonic acid and lowering the ocean's pH (raising its acidity). Since the start of the Industrial Revolution, the pH of the ocean's surface waters has dropped from 8.21 to 8.10. This drop in pH is called ocean acidification.

Past and future carbon dioxide

Natural increases in carbon dioxide concentrations have periodically warmed Earth's temperature during ice age cycles over the past million years or more. The warm episodes (interglacials) began with a small increase in incoming sunlight in the Northern Hemisphere due to variations in Earth's orbit around the Sun and its axis of rotation. (For more details, see the "Milankovitch cycles and ice ages" section of our Climate change: incoming sunlight article.) That little bit of extra sunlight caused a little bit of warming. As the oceans warmed, they outgassed carbon dioxide-like a can of soda going flat in the heat of a summer day. The extra carbon dioxide in the atmosphere greatly amplified the initial, solar-driven warming.

Based on air bubbles trapped in mile-thick ice cores and other paleoclimate evidence, we know that during the ice age cycles of the past million years or so, atmospheric carbon dioxide never exceeded 300 ppm. Before the Industrial Revolution started in the mid-1700s, atmospheric carbon dioxide was 280 ppm or less.

By the time continuous observations began at Mauna Loa Volcanic Observatory in 1958, global atmospheric carbon dioxide was already 315 ppm. Carbon dioxide levels today are higher than at any point in human history. In fact, the last time atmospheric carbon dioxide amounts were this high was more than 3 million years ago, during the Mid-Pliocene Warm Period, when global surface temperature was 4.5-7.2 degrees Fahrenheit (2.5-4 degrees Celsius) warmer than during the pre-industrial era. Sea level was at least 16 feet higher than it was in 1900 and possibly as much as 82 feet higher.

If global energy demand continues to grow rapidly and we meet it mostly with fossil fuels, human emissions of carbon dioxide could reach 75 billion tons per year or more by the end of the century. Atmospheric carbon dioxide could be 800 ppm or higher-conditions not seen on Earth for close to 50 million years.

More on carbon dioxide
NOAA carbon dioxide observations Carbon cycle factsheet Carbon dioxide emissions by country over time Comparing greenhouse gases by their global warming potential Ocean acidification
References

Collins, M., R. Knutti, J. Arblaster, J.-L. Dufresne, T. Fichefet, P. Friedlingstein, X. Gao, W.J. Gutowski, T. Johns, G. Krinner, M. Shongwe, C. Tebaldi, A.J. Weaver and M. Wehner, 2013: Long-term Climate Change: Projections, Commitments and Irreversibility. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Friedlingstein, P., O'Sullivan, M., Jones, M. W., Andrew, R. M., Gregor, L., Hauck, J., Le Quéré, C., Luijkx, I. T., Olsen, A., Peters, G. P., Peters, W., Pongratz, J., Schwingshackl, C., Sitch, S., Canadell, J. G., Ciais, P., Jackson, R. B., Alin, S. R., Alkama, R., ... Zheng, B. (2022). Global Carbon Budget 2022. Earth System Science Data, 14(11), 4811-4900. https://doi.org/10.5194/essd-14-4811-2022

Lan, X., B. D. Hall, G. Dutton, J. Mühle, J. W. Elkins, and I. J. Vimont. (2022). Long-lived greenhouses gases [in State of the Climate in 2021, Chapter 2: Global Climate]. Bulletin of the American Meteorological Society, 103 (8), S81-S84. https://doi.org/10.1175/BAMS-D-22-0092.1.

Lüthi, D., M. Le Floch, B. Bereiter, T. Blunier, J.-M. Barnola, U. Siegenthaler, D. Raynaud, J. Jouzel, H. Fischer, K. Kawamura, and T.F. Stocker. (2008). High-resolution carbon dioxide concentration record 650,000-800,000 years before present. Nature, Vol. 453, pp. 379-382. doi:10.1038/nature06949.

Woods Hole Oceanographic Institution. (2015). Introduction to ocean acidification. Accessed October 4, 2017.

Lindsey, R. (2009). Climate and Earth's energy budget. Accessed October 4, 2017.

Based on the annual report from NOAA's Global Monitoring Lab, global average atmospheric carbon dioxide was 417.06 parts per million ("ppm" for short) in 2022, setting a new record high. The increase between 2021 and 2022 was 2.13 ppm-the 11 th year in a row where the amount of carbon dioxide in the atmosphere increased by more than 2 ppm. At Mauna Loa Observatory in Hawaii, where the modern carbon dioxide record began in 1958, the annual average carbon dioxide in 2022 was 418.56.

Carbon dioxide concentrations are rising mostly because of the fossil fuels that people are burning for energy. Fossil fuels like coal and oil contain carbon that plants pulled out of the atmosphere through photosynthesis over many millions of years; we are returning that carbon to the atmosphere in just a few hundred. Since the middle of the 20 th century, annual emissions from burning fossil fuels have increased every decade, from close to 11 billion tons of carbon dioxide per year in the 1960s to an estimated 36.6 billion tons in 2022 according to the Global Carbon Budget 2022.

Carbon cycle experts estimate that natural "sinks"-processes that remove carbon from the atmosphere-on land and in the ocean absorbed the equivalent of about half of the carbon dioxide we emitted each year in the 2011-2020 decade. Because we put more carbon dioxide into the atmosphere than natural sinks can remove, the total amount of carbon dioxide in the atmosphere increases every year.

The more we overshoot what natural processes can remove in a given year, the faster the atmospheric concentration of carbon dioxide rises. In the 1960s, the global growth rate of atmospheric carbon dioxide was roughly 0.8± 0.1 ppm per year. Over the next half century, the annual growth rate tripled, reaching 2.4 ppm per year during the 2010s. The annual rate of increase in atmospheric carbon dioxide over the past 60 years is about 100 times faster than previous natural increases, such as those that occurred at the end of the last ice age 11,000-17,000 years ago.

Why carbon dioxide matters

Carbon dioxide is Earth's most important greenhouse gas: a gas that absorbs and radiates heat. Unlike oxygen or nitrogen (which make up most of our atmosphere), greenhouse gases absorb heat radiating from the Earth's surface and re-release it in all directions-including back toward Earth's surface. Without carbon dioxide, Earth's natural greenhouse effect would be too weak to keep the average global surface temperature above freezing. By adding more carbon dioxide to the atmosphere, people are supercharging the natural greenhouse effect, causing global temperature to rise. According to observations by the NOAA Global Monitoring Lab, in 2021 carbon dioxide alone was responsible for about two-thirds of the total heating influence of all human-produced greenhouse gases.

Another reason carbon dioxide is important in the Earth system is that it dissolves into the ocean like the fizz in a can of soda. It reacts with water molecules, producing carbonic acid and lowering the ocean's pH (raising its acidity). Since the start of the Industrial Revolution, the pH of the ocean's surface waters has dropped from 8.21 to 8.10. This drop in pH is called ocean acidification.

Past and future carbon dioxide

Natural increases in carbon dioxide concentrations have periodically warmed Earth's temperature during ice age cycles over the past million years or more. The warm episodes (interglacials) began with a small increase in incoming sunlight in the Northern Hemisphere due to variations in Earth's orbit around the Sun and its axis of rotation. (For more details, see the "Milankovitch cycles and ice ages" section of our Climate change: incoming sunlight article.) That little bit of extra sunlight caused a little bit of warming. As the oceans warmed, they outgassed carbon dioxide-like a can of soda going flat in the heat of a summer day. The extra carbon dioxide in the atmosphere greatly amplified the initial, solar-driven warming.

Based on air bubbles trapped in mile-thick ice cores and other paleoclimate evidence, we know that during the ice age cycles of the past million years or so, atmospheric carbon dioxide never exceeded 300 ppm. Before the Industrial Revolution started in the mid-1700s, atmospheric carbon dioxide was 280 ppm or less.

By the time continuous observations began at Mauna Loa Volcanic Observatory in 1958, global atmospheric carbon dioxide was already 315 ppm. Carbon dioxide levels today are higher than at any point in human history. In fact, the last time atmospheric carbon dioxide amounts were this high was more than 3 million years ago, during the Mid-Pliocene Warm Period, when global surface temperature was 4.5-7.2 degrees Fahrenheit (2.5-4 degrees Celsius) warmer than during the pre-industrial era. Sea level was at least 16 feet higher than it was in 1900 and possibly as much as 82 feet higher.

If global energy demand continues to grow rapidly and we meet it mostly with fossil fuels, human emissions of carbon dioxide could reach 75 billion tons per year or more by the end of the century. Atmospheric carbon dioxide could be 800 ppm or higher-conditions not seen on Earth for close to 50 million years.

More on carbon dioxide
NOAA carbon dioxide observations Carbon cycle factsheet Carbon dioxide emissions by country over time Comparing greenhouse gases by their global warming potential Ocean acidification
References

Collins, M., R. Knutti, J. Arblaster, J.-L. Dufresne, T. Fichefet, P. Friedlingstein, X. Gao, W.J. Gutowski, T. Johns, G. Krinner, M. Shongwe, C. Tebaldi, A.J. Weaver and M. Wehner, 2013: Long-term Climate Change: Projections, Commitments and Irreversibility. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Friedlingstein, P., O'Sullivan, M., Jones, M. W., Andrew, R. M., Gregor, L., Hauck, J., Le Quéré, C., Luijkx, I. T., Olsen, A., Peters, G. P., Peters, W., Pongratz, J., Schwingshackl, C., Sitch, S., Canadell, J. G., Ciais, P., Jackson, R. B., Alin, S. R., Alkama, R., ... Zheng, B. (2022). Global Carbon Budget 2022. Earth System Science Data, 14(11), 4811-4900. https://doi.org/10.5194/essd-14-4811-2022

Lan, X., B. D. Hall, G. Dutton, J. Mühle, J. W. Elkins, and I. J. Vimont. (2022). Long-lived greenhouses gases [in State of the Climate in 2021, Chapter 2: Global Climate]. Bulletin of the American Meteorological Society, 103 (8), S81-S84. https://doi.org/10.1175/BAMS-D-22-0092.1.

Lüthi, D., M. Le Floch, B. Bereiter, T. Blunier, J.-M. Barnola, U. Siegenthaler, D. Raynaud, J. Jouzel, H. Fischer, K. Kawamura, and T.F. Stocker. (2008). High-resolution carbon dioxide concentration record 650,000-800,000 years before present. Nature, Vol. 453, pp. 379-382. doi:10.1038/nature06949.

Woods Hole Oceanographic Institution. (2015). Introduction to ocean acidification. Accessed October 4, 2017.

Lindsey, R. (2009). Climate and Earth's energy budget. Accessed October 4, 2017.

# data[].attributes.attachment_link.title
Climate Change: Atmospheric Carbon Dioxide

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In the past 60 years, carbon dioxide in the atmosphere has increased 100 times faster than it did during the end of the last ice age.

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https://iopscience.iop.org/article/10.1088/1748-9326/7/2/024013/meta

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Author affiliations

¹ Met Office Hadley Centre, FitzRoy Road, Exeter, UK

Author notes

² Present address: Laboratoire de Météorologie Dynamique, IPSL, CNRS/UPMC, Paris, France.

³ Present address: EUMETSAT, Darmstadt, Germany.

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1748-9326/7/2/024013

Abstract

We use the HadGEM2-ES Earth System model to examine the degree of reversibility of a wide range of components of the Earth System under idealized climate change scenarios where the atmospheric CO ₂ concentration is gradually increased to four times the pre-industrial level and then reduced at a similar rate from several points along this trajectory. While some modelled quantities respond almost immediately to the atmospheric CO ₂ concentrations, others exhibit a time lag relative to the change in CO ₂. Most quantities also exhibit a lag relative to the global-mean surface temperature change, which can be described as a hysteresis behaviour. The most surprising responses are from low-level clouds and ocean stratification in the Southern Ocean, which both exhibit hysteresis on timescales longer than expected. We see no evidence of critical thresholds in these simulations, although some of the hysteresis phenomena become more apparent above 2 × CO ₂ or 3 × CO ₂. Our findings have implications for the parametrization of climate impacts in integrated assessment and simple climate models and for future climate studies of geoengineering scenarios.

There is considerable uncertainty in future emission and concentration pathways of greenhouse gases. Mitigation scenarios aiming to avoid potentially dangerous climate change are likely to require significant reductions in greenhouse gas emissions within the next two decades (Mignone et al 2008, Rogelj et al 2011). However, it is conceivable that early CO ₂ emissions reduction may not be achieved and the current rapid growth in greenhouse gas concentrations (Friedlingstein et al 2010) may continue for at least several decades. This creates an urgent need to understand whether the undesirable elements of climate change that occur during the global warming period can be reversed in a usefully short time if ever it becomes possible in the future to lower the atmospheric concentration of greenhouse gases through economically viable CO ₂ air capture (Matthews 2010), possibly associated with a rapid decarbonization of the economy.

Earth's climate is a dynamic system whose components respond on different timescales to external forcings. While the atmosphere adjusts quickly to its boundary conditions, the response of the system as a whole is largely controlled by the ocean, the cryosphere, the land surface and some biogeochemical cycles, all of which respond over a much wider range of timescales. The longer timescales are associated with processes such as mixing into the deep ocean and ocean circulation, diffusion of heat and moisture in the deeper soil, vegetation growth and carbon cycling, and ice sheet formation and melting. These components introduce inertia into the system, leading to significant time lags between a forcing and the response it induces. For instance it is well known that in stabilization scenarios the global-mean surface temperature (GMST) response lags the radiative forcing because of the thermal inertia of the global ocean, a process known as constant concentration warming commitment (Wigley 2005, Hare and Meinshausen 2007). Scenarios where atmospheric concentrations of greenhouse gases exceed a particular target before decreasing towards that target are known as 'overshoot' or 'peak-and-decline' scenarios (Huntingford and Lowe 2007). Such scenarios may be characterized by hysteresis effects and irreversible changes. Irreversibility means that the system cannot be restored to its initial state or only does so on a timescale far longer than those normally considered practical from a human perspective. Hysteresis refers here to the dependence of the climate system not only on its current environment (measured either by the atmospheric CO ₂ concentration or the GMST) but also on its past environment. In many cases this arises because there is a lag between the input variable (e.g., atmospheric CO ₂ concentration) and the output variable (e.g., global-mean precipitation). In this study irreversibility implies hysteresis, but hysteresis does not necessarily imply irreversibility. Finally it should be noted that hysteresis effects do not necessarily lead to the existence of multiple equilibria in the system as we only consider transient simulations.

Reversibility in the climate system has been looked at for the carbon cycle in the context of zero-emission commitment scenarios either with an Earth System Model of Intermediate Complexity (Solomon et al 2009) or coupled carbon-climate models (Lowe et al 2009, Frölicher and Joos 2010). Reversibility has also been investigated in three-dimensional climate models for physical climate variables such as precipitation, sea-ice, sea-level rise or cloud feedbacks (Yoshida et al 2005, Frölicher and Joos 2010, Samanta et al 2010, Wu et al 2010, Cao et al 2011). The closest experimental setup to ours is that of Samanta et al ( 2010) who increased the CO ₂ atmospheric concentration from 350 to 700 ppmv and decreased it back to 350 ppmv in an atmospheric model coupled to a slab ocean model. The recent advent of second generation of Earth System models such as the Met Office Hadley Centre HadGEM2-ES model (Collins et al 2011, Jones et al 2011) allows reversibility and hysteresis effects to be examined in a self-consistent framework and for a much wider range of Earth System components than has previously been possible. The objective of this study is to provide an overview of these effects in the HadGEM2-ES model and guide future research on specific components and processes of the Earth system.

The Hadley Centre Global Environment Model version 2 Earth System model (HadGEM2-ES) is a state-of-the-art model that can be used to investigate how couplings and feedbacks may affect the response of the Earth System to climate forcing. It comprises a physical coupled atmosphere-ocean-sea-ice model with the addition of component models for atmospheric aerosols, tropospheric chemistry and the terrestrial and oceanic carbon cycle to characterize various aspects and couplings within the Earth system. Some processes, such as permafrost processes, ice sheets and glacier dynamics, and ground water recharge, are not or only partly included in the model, although it is recognized that they could play a role in reversibility issues. A detailed description of the Earth System model can be found in Collins et al ( 2011). The model includes a representation of the carbon cycle for terrestrial and oceanic ecosystems with interactive vegetation (five different plant functional types) and plankton distributions (diatoms and non-diatoms phytoplankton and zooplankton). The impact of dust fertilization on plankton growth is represented, and DMS production by plankton is a source of aerosols. The ozone and methane concentrations as well as the sulfate oxidant fields vary with the meteorology and the climate. Seven aerosols species are represented in the model, namely sulfate, biomass burning aerosol, black and organic carbon from fossil fuel burning, sea-salt, mineral dust, and biogenic aerosols. They interact with the atmosphere through direct and indirect effects and are coupled with other model components.

A traditional benchmark CMIP experiment consists of increasing the CO ₂ atmospheric concentration by 1% yr −1 starting from an initial concentration of 286 ppmv which corresponds to that of year 1850. This experiment is generally used to investigate the transient climate response to the forcing by greenhouse gases. We build on this 1% CO ₂ experiment by constructing five different scenarios. In the first scenario, we ramp-up the CO ₂ atmospheric concentration by 1% yr −1 starting from the initial concentration (286 ppmv) and finishing at four times that concentration (1144 ppmv). Four ramp-down scenarios have been branched at different points along this increasing concentration. The CO ₂ concentration is decreased at 1% yr −1 starting at four different concentration levels (4 × CO ₂, 3 × CO ₂, 2 × CO ₂ and 1.5 × CO ₂), giving a range of radiative forcing increases of up to around 7.5 Wm −2 covering much of the range spanned by the new policy-relevant simulations for the next IPCC assessment (Moss et al 2010). Several techniques have been proposed to remove carbon dioxide from the atmosphere, either through large-scale biomass growth coupled with carbon sequestration, modification of the ocean chemical composition, acceleration of the carbonate cycle or direct air capture. The potential for successful carbon dioxide removal using these techniques is uncertain, and the current proposed methods cannot achieve the level required to sustain a 1% decrease per year in atmospheric CO ₂ concentration. However it is not uncommon to investigate unusual climate scenarios with more simple climate models. Performing such peak-and-decline scenarios with a full Earth System model is a good test of whether the simple models have the right parametrizations to operate under conditions of decreasing concentrations of greenhouse gases.

It should be noted that because the CO ₂ atmospheric concentration is prescribed, the C budget is not closed. The CO ₂ fluxes between the atmosphere and the ocean and between the atmosphere and the land surface are only diagnostics in these simulations. Nonetheless they can be used to understand how the carbon-climate feedback operates as described in Hibbard et al ( 2007) and Jones et al ( 2011). It is also recognized that the ramp-down part of the scenario is unrealistic as it would necessitate very large negative C emissions as discussed further below.

3.1. Atmospheric component

GMST increases at a near-constant rate when CO ₂ concentration increases exponentially and is about 5.5 °C above the pre-industrial value at the time of CO ₂ quadrupling (figure 1). When the CO ₂ concentration starts to decrease, the temperature change reverses immediately over land but with a time lag over the ocean, as found previously for lower rates of greenhouse gas reduction. We find that the larger the CO ₂ peak concentration, the longer is this time lag (it is up to 20 yr when CO ₂ concentration peaks at four times the pre-industrial value). For the 2 × CO ₂ ramp-up and ramp-down, the time lag is about 10 yr and is consistent with that found by Samanta et al ( 2010). The GMST change remains 0.5-1.2 °C above its initial value by the time CO ₂ returns to its pre-industrial value (figure 1(b)). Since many components of the climate system are driven by surface temperature, we present further changes in the system as a function of the GMST but we recognize that some variables such as precipitation and continental ecosystems also respond to the CO ₂ concentration (Cao et al 2011, Andrews et al 2010). We try to identify critical CO ₂ concentrations and GMST changes beyond which the changes in some components either become irreversible or relax to their pre-industrial state on a much longer timescale.

The variations in global-mean precipitation are dominated by changes over the oceans, while land precipitation changes are noisy and less systematic (figures 2(a) and (b)). The global-mean precipitation shows a clear hysteresis behaviour in all four experiments, confirming earlier findings using the HadCM3 model (Wu et al 2010, Cao et al 2011). For a given GMST change, precipitation is also greater on the ramp-down CO ₂ pathway than on the ramp-up path. Two explanations for this phenomenon have been provided in previous studies. It has been shown that the precipitation response to an increase in CO ₂ atmospheric concentration can be decomposed into a (positive) slow response proportional to surface temperature change and a (negative) fast adjustment to the CO ₂ radiative forcing (Andrews et al 2010, Cao et al 2011). The hysteresis is due to the decoupling between the two terms that occurs during the ramp-down phase. It is also possible to explain the hysteresis as a response to a changing imbalance in the ocean surface energy budget (Wu et al 2010). Preference for one or the other explanation depends on whether one considers the hydrological cycle to respond to the atmospheric or surface heat budget. It is interesting that precipitation extremes (measured here as the land average of the local daily maximum precipitation rate in a year) show no hysteresis, pointing to a potentially higher degree of reversibility for hydrological climate impacts (figure 2(c)).

Clouds also respond to the CO ₂ forcing, with high-level cloud increasing and low- and mid-level cloud decreasing during the ramp-up phase, and a general tendency to opposite behaviour as the CO ₂ is reduced (figures 2(d)-(f)). Such changes in the global-mean cloud amounts are well established (Mitchell and Ingram 1992) and have also been confirmed in more recent studies (Ringer et al 2006). Examination of the radiative impact of the individual cloud types (not shown) indicates a high degree of compensation between the net effects of the changes in high- and middle-level clouds in both the ramp-up and ramp-down phases. The radiative impact of the changes in low-level cloud is small because it primarily results from changes in optically thin clouds and smaller changes of opposite sign in optically thicker clouds. An interesting feature of the ramp-down phase is the lagged response of low-level clouds which show a small hysteresis effect. Further examination reveals that this is primarily an oceanic effect, depending, like the precipitation, on the balance between fast and slow responses and also on the geographical pattern of the SST change. In contrast, over land changes in all cloud types reverse almost immediately with surface temperature when CO ₂ is decreased.

3.2. Oceanic component

Ocean heat uptake relates closely to the thermal expansion component of sea-level rise, which may dominate 21st century sea level increases (Meehl et al 2007). By the time the CO ₂ concentration has risen to four times pre-industrial levels the model projects the ocean heat content (figure 2(g)) to have increased by 3 × 10 ²⁴ J, with a thermal expansion of about 40 cm. After the forcing declines from 4 × CO ₂ the heat content continues to increase by a further 60% over the next century. The time between the peaks in forcing and ocean heat uptake varies strongly with the magnitude of the peak forcing, ranging from approximately 25 yr (1.5 × CO ₂) to a century (4 × CO ₂). This shows that only a rapid reduction in radiative forcing might be able to limit and reduce the thermal expansion component of sea-level rise before some of the most severe coastal impacts are realized. The annual mean Arctic and Antarctic sea-ice covers are entirely reversible up to 4 × CO ₂; the recovery has a 50 yr lag over CO ₂ but no lag over the GMST in line with earlier findings (Yoshida et al 2005, Samanta et al 2010, Tietsche et al 2011, see figure 2(j)). This is in contrast with the results from a simple model used by Abbot et al ( 2011) who found that cloud and heat transport feedbacks could lead to bifurcations in the state of Arctic sea-ice, which would lead to possible hysteresis effects in the ramp-up and ramp-down scenario we consider. The Atlantic meridional overturning circulation (AMOC) seems to be reversible in all four cases, although there is a lag of 2-3 decades in the 3 × and 4 × CO ₂ ramp-down experiments. For these two cases, the AMOC weakening trend continues to undershoot further after CO ₂ ramp-down before the recovery starts. In all cases, the AMOC recovers to its normal strength during the later stabilization period after CO ₂ returns to the pre-industrial level (not shown).

Unlike the ocean heat content, the ocean carbon content shows a decrease soon after the forcing reverses (figure 2(h)). To first order, both the ocean heat and carbon contents are governed by atmosphere-ocean gradients and the exchange between the mixed layer and the deep ocean. Whilst throughout these simulations the surface ocean is colder than the atmosphere by the mixing up of cold water from depth, until atmospheric CO ₂ concentrations become very high, mixing with the deep ocean is always enriching the surface waters in CO ₂. Deep mixing is therefore acting to increase the ocean-atmosphere temperature gradient, delaying the turnover in air-sea heat flux until towards the end of our simulations, but decreases the ocean-atmosphere CO ₂ gradient, causing the ocean to become a source of CO ₂ to the atmosphere only a few decades after the ramp-down starts. This results in a timescale for equilibrating ocean heat in the ramp-down that is much longer than that for equilibrating the CO ₂, at least in the ocean mixed layer. The ocean surface pH responds very quickly to atmospheric concentrations and is almost totally reversible in the global mean. However some of the impact of ocean acidification on marine ecosystems, for example on calcification (Riebesell et al 2000, Iglesias-Rodriguez et al 2008), may not be reversible in the same way, and may even feed back to limit the pH reversibility through changes in alkalinity not considered in our simulations. Deeper ocean pH and changes in the depth of the lysocline do not experience the reversibility experienced in the surface ocean.

Major nutrient concentrations simulated in the surface ocean waters decreases almost linearly under the increasing greenhouse gas forcing. Nutrients available for photosynthesis (i.e., those at the surface ocean where light can penetrate) are expected to decrease under global warming (Behrenfeld 2006), and this occurs in the model as the ocean warms and stratifies, slowing the replenishment of nutrients from depth. An unexpected feature of these experiments is that, despite the mixed layer thickness in most of the ocean recovering in line with the removal of heat from the surface ocean, the globally averaged recovery of surface nutrient concentrations is very slow (figure 2(i)). The limited nutrient recovery results from a significant (>century) lag in the recovery of freshwater-driven stratification over much of the Southern Ocean, preventing upwelling of nutrient-rich waters from depth. This effect could have long-lasting consequences for marine productivity. The persistence of a low-salinity lid across much of the Southern Ocean can be understood as a simple function of the time lag between supply of freshwater through precipitation and removal of that water by mixing. Even if the high-latitude precipitation response to our forcing were to be perfectly reversible and simply scale with that forcing, since the salinity at any point in time integrates the changing freshwater flux over some interval prior to that point in time, and since the preceding precipitation is different to the present-day one during the ramp-up and ramp-down periods, a lag in surface salinity, independent of the complexities of the ocean physical circulation, is to be expected.

3.3. Terrestrial component

Soil moisture changes differ by depth. Moisture changes in the top (10 cm) soil layer responds linearly to changes and are completely reversible. Moisture changes in the bottom (1-3 m) soil layer shows much more of a lag when responding back to a decrease in CO ₂ concentration because of the inertia associated with the deep soil hydrology. We calculated a drought diagnostic from the anomaly of soil moisture in the top 1 m of the soil. A soil moisture anomaly threshold was created for each grid cell based on the 20th percentile distribution of monthly soil moisture anomalies for the first 10 yr of the simulation. Any time the soil moisture anomaly falls below this threshold the grid cell is assumed to be in drought for that month. Figure 2(k) shows the proportion of the land surface that is in drought at any particular year (it is 20% on average during the first 10 yr of the simulation). The hysteresis arises because it takes time for the changes in the forcing meteorology to impact the soil moisture down to a depth of 1 m. The permafrost fraction over land (diagnosed from monthly soil temperatures) shows a hysteresis effect as a function of the GMST, with approximately 20% less permafrost area in the ramp-down than in the ramp-up experiment figure 2(l). Although permafrost extent is eventually fully reversible, any loss of organic carbon during the time thawed would be effectively irreversible as this has accumulated over many millennia. The various vegetation types in the model exhibit different behaviour when the atmospheric CO ₂ concentration changes. Changes in vegetation fraction are not linear with temperature because they are driven by their carbon balance which depends on both climate and CO ₂ fertilization (Gregory et al 2009, Denman et al 2007) and competition between vegetation types. When the CO ₂ concentration increases, the bare soil fraction decreases while trees, shrub and grass fractions increase globally. Gross primary production (GPP) over land responds linearly with the logarithm of CO ₂ in the ramping up phase. However both vegetation and soils continue to take up carbon many years after the atmospheric CO ₂ concentration is diminished (figures 2(m) and (n)). For vegetation carbon, this is because of the long response time associated with vegetation competition. Trees continue to increase in the NH high latitudes after the peak in CO ₂ and temperature and this overwhelms the decrease in the fertilization effect. For soil carbon, this is because of the long lag between the increase in soil carbon pools and the increase in heterotrophic respiration.

3.4. Further discussion on the carbon cycle

Figure 3 shows the time-latitude Hovmöller diagrams of surface pH, surface nutrient concentration, vegetation carbon and soil carbon. There is a small hysteresis in pH (figure 3(a)). In the Arctic for CO ₂ concentrations of 300-400 ppmv (roughly the first and last 40 yr), pH is on average 0.06 smaller in the ramp-down phase. While the global-mean surface ocean pH is almost totally reversible, regional variations are to be expected because of changes in sea-ice and freshwater budget as underlined by Steinacher et al ( 2009). Much of the global-mean reduction in surface nutrient concentration seen in figure 2(i) is due to large reductions seen at high latitudes (figure 3(b)) caused by fresher, more stable, surface waters. At lower latitudes the zonal signal is dominated by reductions in upwelling regions. Figures 3(c) and (d) show the terrestrial carbon stores. In the tropics the terrestrial carbon stores are fully reversible within the timescale of the simulation. The timescale of reversibility is longer at higher latitudes and these regions are mostly responsible for the hysteresis seen in figures 2(m) and (n). Carbon store changes at lower latitudes are caused by increases/decreases in the carbon density of forests, while at higher latitudes the increase is caused by an increase in forest area. Soil carbon peaks before vegetation carbon, because soil carbon varies with NPP which is closely linked to the atmospheric CO ₂ concentration, while the peak in vegetation carbon is delayed by the slow expansion in the area of forest.

Figure 4 shows the positive and negative emissions (GtC yr −1) necessary to close the CO ₂ atmospheric budget in the ramp-up and ramp-down phases. It can be observed that the peak decrease is only about half the peak increase. This is because there is still some natural uptake after the peak so the negative emissions are offset by some continued terrestrial and oceanic increase. The ramp-down negative emissions are almost flat (especially when ramping down from 4 × CO ₂). This is because the offsetting from natural uptake lessens and then reverses while the effort to bring atmospheric concentrations down keeps decreasing as the 1% profile levels off (i.e., the absolute rate of ramp-down decreases in time). The cumulative emissions amount to 3250 GtC to get to the 4 × CO ₂ peak. The atmospheric increase is about 1820 GtC, which corresponds to an average airborne fraction of 56%. On the way down, cumulative negative emissions are about − 2400 GtC so a smaller equivalent amount of CO ₂ has to be taken out than was initially introduced. A fact relevant to CDR technology is that any negative emission will be subject to an airborne fraction in the same way as positive emissions. During the ramp-down phase, the average airborne fraction is 76%, which is significantly greater than during the ramp-up phase (as the natural sinks are still responding at the beginning of the ramp-down).

We have investigated hysteresis and irreversibility in the Earth system using a highly idealized experiment in which the atmospheric CO ₂ concentration is first ramped up and then ramped back down to its initial level. Although the scenario is unrealistic because of the requirement for large negative C emissions in the ramp-down phase, it is useful to investigate hysteresis and irreversibility in the Earth system and can provide insight into a hypothetical scenario of carbon dioxide removal. In summary only the ocean surface pH responds almost immediately to the atmospheric CO ₂ concentrations in our experiments. Other quantities exhibit some time lag relative to the change in CO ₂ and most also exhibit a lag relative to the GMST, which we describe as a hysteresis behaviour in CO ₂ or GMST space. For certain quantities, such as precipitation, the hysteresis in GMST space occurs as a response to asynchronous variations in CO ₂ and GMST. For ocean heat content or permafrost area, the hysteresis arises because the quantity is not in equilibrium with GMST and depends on processes operating on longer timescales. Longer experiments would be required to discriminate hysteresis phenomena due to inertia from those reflecting a bi-stability or multiple equilibria in the system.

The most surprising responses are those in low-level clouds and ocean stratification in the Southern Ocean, which both exhibit hysteresis on timescales longer than expected. We did not see evidence of critical thresholds in these simulations, although some of the hysteresis phenomena become more apparent above 2 × CO ₂ or 3 × CO ₂. We summarize in table 1 potential implications of our results for climate impact studies. Overall it appears that the most significant hysteresis in the HadGEM2-ES model is for variables relating to terrestrial and marine ecosystems. In contrast physical changes in the model show little hysteresis (except for sea-level rise). The latter is consistent with the findings from Samanta et al ( 2010) who found that physical climate parameters return to their initial values soon after the CO ₂ concentration does in a similar 2 × CO ₂ ramp-up and ramp-down experiment.

Table 1. Qualitative interpretation of our results for the reversibility of key climate impacts and feedbacks in ramp-up and ramp-down experiments.

Climate impacts

Degree of reversibility in ramp-down experiments

Remarks

Land surface

Land surface temperatures reverse quicker than ocean surface temperature although permafrost shows delay in recovery

Heat generation due to decomposition of organic matter in permafrost (Khvorostyanov et al 2008), thermokarst development and loss of ground ice (Schuur et al 2008, O'Connor et al 2010) may delay permafrost recovery further. Despite the physical permafrost extent being reversible, any organic carbon lost while thawed will not be

Precipitation

Global-mean precipitation shows hysteresis but land precipitation and extreme precipitation do not

Arctic sea-ice

Arctic sea-ice cover shows a high degree of reversibility in terms of the GMST

Sea-level rise

Sea-level rise from thermal expansion shows very-long timescale inertia. Only in the 1.5 × CO ₂ ramp-down experiment does sea level stabilize and decrease

Other components to sea-level rise may cause further irreversibility

Marine ecosystems

The model shows evidence of long-lasting impact on nutrient availability in the Southern Ocean

Effects of acidification on marine ecosystems may lead to further irreversible changes

Continental ecosystems

Vegetation dynamics can induce long timescale inertia in the system which can offset the decreasing fertilization effect

Nutrient availability may limit ecosystem response to climate change. Changes in fire regime, not modelled here, may trigger rapid ecosystem changes and introduce long lags in recovery

Carbon cycle feedbacks

Ocean carbon storage responds more quickly to ramp-down than ocean heat uptake, and rapidly releases stored carbon back to atmosphere. Land carbon storage continues to increase slowly immediately after start of ramp-down and shows a significant hysteresis lag due to the inertia of vegetation and long-lived soil carbon pools

This has implications for projections of future CO ₂ under overshoot or negative emissions scenarios such as RCP2.6

It is common to parameterize climate impacts in integrated assessment models and simple climate models as a function of the global-mean surface temperature change. While such a parametrization may be justified by the large uncertainties in damage cost functions and the monotonous and phased increase in CO ₂ concentration, surface temperature and climate impacts in most scenarios, our results bring evidence that climate impacts cannot be parameterized as a function of GMST alone in unconventional scenarios such as those with CO ₂ overshooting. A geoengineering scenario where the CO ₂ atmospheric concentration peaks at levels much higher than today's before decreasing rapidly may experience delayed climate impacts. Determining more precisely which impacts may be irreversible will require even more complex representation of the Earth system with a focus on components which are potential sources of irreversibility, such as ice sheets, soil carbon in permafrost regions and terrestrial and oceanic ecosystem biodiversity.

This work was funded by the Joint DECC/Defra Met Office Hadley Centre Climate Programme (GA01101) and by the European Commission's 7th Framework programme, under grant agreement number 226520, COMBINE project, and grant agreement number 282672, EMBRACE project. We thank two anonymous reviewers for their useful comments.

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Reversibility in an Earth System model in response to CO2 concentration changes

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1 Met Office Hadley Centre, FitzRoy Road, Exeter, UK 2 Present address: Laboratoire de Météorologie Dynamique, IPSL, CNRS/UPMC, Paris, France. 3 Present address: EUMETSAT, Darmstadt, Germany.

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Author affiliations

¹ Met Office Hadley Centre, FitzRoy Road, Exeter, UK

Author notes

² Present address: Laboratoire de Météorologie Dynamique, IPSL, CNRS/UPMC, Paris, France.

³ Present address: EUMETSAT, Darmstadt, Germany.

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Abstract

We use the HadGEM2-ES Earth System model to examine the degree of reversibility of a wide range of components of the Earth System under idealized climate change scenarios where the atmospheric CO ₂ concentration is gradually increased to four times the pre-industrial level and then reduced at a similar rate from several points along this trajectory. While some modelled quantities respond almost immediately to the atmospheric CO ₂ concentrations, others exhibit a time lag relative to the change in CO ₂. Most quantities also exhibit a lag relative to the global-mean surface temperature change, which can be described as a hysteresis behaviour. The most surprising responses are from low-level clouds and ocean stratification in the Southern Ocean, which both exhibit hysteresis on timescales longer than expected. We see no evidence of critical thresholds in these simulations, although some of the hysteresis phenomena become more apparent above 2 × CO ₂ or 3 × CO ₂. Our findings have implications for the parametrization of climate impacts in integrated assessment and simple climate models and for future climate studies of geoengineering scenarios.

There is considerable uncertainty in future emission and concentration pathways of greenhouse gases. Mitigation scenarios aiming to avoid potentially dangerous climate change are likely to require significant reductions in greenhouse gas emissions within the next two decades (Mignone et al 2008, Rogelj et al 2011). However, it is conceivable that early CO ₂ emissions reduction may not be achieved and the current rapid growth in greenhouse gas concentrations (Friedlingstein et al 2010) may continue for at least several decades. This creates an urgent need to understand whether the undesirable elements of climate change that occur during the global warming period can be reversed in a usefully short time if ever it becomes possible in the future to lower the atmospheric concentration of greenhouse gases through economically viable CO ₂ air capture (Matthews 2010), possibly associated with a rapid decarbonization of the economy.

Earth's climate is a dynamic system whose components respond on different timescales to external forcings. While the atmosphere adjusts quickly to its boundary conditions, the response of the system as a whole is largely controlled by the ocean, the cryosphere, the land surface and some biogeochemical cycles, all of which respond over a much wider range of timescales. The longer timescales are associated with processes such as mixing into the deep ocean and ocean circulation, diffusion of heat and moisture in the deeper soil, vegetation growth and carbon cycling, and ice sheet formation and melting. These components introduce inertia into the system, leading to significant time lags between a forcing and the response it induces. For instance it is well known that in stabilization scenarios the global-mean surface temperature (GMST) response lags the radiative forcing because of the thermal inertia of the global ocean, a process known as constant concentration warming commitment (Wigley 2005, Hare and Meinshausen 2007). Scenarios where atmospheric concentrations of greenhouse gases exceed a particular target before decreasing towards that target are known as 'overshoot' or 'peak-and-decline' scenarios (Huntingford and Lowe 2007). Such scenarios may be characterized by hysteresis effects and irreversible changes. Irreversibility means that the system cannot be restored to its initial state or only does so on a timescale far longer than those normally considered practical from a human perspective. Hysteresis refers here to the dependence of the climate system not only on its current environment (measured either by the atmospheric CO ₂ concentration or the GMST) but also on its past environment. In many cases this arises because there is a lag between the input variable (e.g., atmospheric CO ₂ concentration) and the output variable (e.g., global-mean precipitation). In this study irreversibility implies hysteresis, but hysteresis does not necessarily imply irreversibility. Finally it should be noted that hysteresis effects do not necessarily lead to the existence of multiple equilibria in the system as we only consider transient simulations.

Reversibility in the climate system has been looked at for the carbon cycle in the context of zero-emission commitment scenarios either with an Earth System Model of Intermediate Complexity (Solomon et al 2009) or coupled carbon-climate models (Lowe et al 2009, Frölicher and Joos 2010). Reversibility has also been investigated in three-dimensional climate models for physical climate variables such as precipitation, sea-ice, sea-level rise or cloud feedbacks (Yoshida et al 2005, Frölicher and Joos 2010, Samanta et al 2010, Wu et al 2010, Cao et al 2011). The closest experimental setup to ours is that of Samanta et al ( 2010) who increased the CO ₂ atmospheric concentration from 350 to 700 ppmv and decreased it back to 350 ppmv in an atmospheric model coupled to a slab ocean model. The recent advent of second generation of Earth System models such as the Met Office Hadley Centre HadGEM2-ES model (Collins et al 2011, Jones et al 2011) allows reversibility and hysteresis effects to be examined in a self-consistent framework and for a much wider range of Earth System components than has previously been possible. The objective of this study is to provide an overview of these effects in the HadGEM2-ES model and guide future research on specific components and processes of the Earth system.

The Hadley Centre Global Environment Model version 2 Earth System model (HadGEM2-ES) is a state-of-the-art model that can be used to investigate how couplings and feedbacks may affect the response of the Earth System to climate forcing. It comprises a physical coupled atmosphere-ocean-sea-ice model with the addition of component models for atmospheric aerosols, tropospheric chemistry and the terrestrial and oceanic carbon cycle to characterize various aspects and couplings within the Earth system. Some processes, such as permafrost processes, ice sheets and glacier dynamics, and ground water recharge, are not or only partly included in the model, although it is recognized that they could play a role in reversibility issues. A detailed description of the Earth System model can be found in Collins et al ( 2011). The model includes a representation of the carbon cycle for terrestrial and oceanic ecosystems with interactive vegetation (five different plant functional types) and plankton distributions (diatoms and non-diatoms phytoplankton and zooplankton). The impact of dust fertilization on plankton growth is represented, and DMS production by plankton is a source of aerosols. The ozone and methane concentrations as well as the sulfate oxidant fields vary with the meteorology and the climate. Seven aerosols species are represented in the model, namely sulfate, biomass burning aerosol, black and organic carbon from fossil fuel burning, sea-salt, mineral dust, and biogenic aerosols. They interact with the atmosphere through direct and indirect effects and are coupled with other model components.

A traditional benchmark CMIP experiment consists of increasing the CO ₂ atmospheric concentration by 1% yr −1 starting from an initial concentration of 286 ppmv which corresponds to that of year 1850. This experiment is generally used to investigate the transient climate response to the forcing by greenhouse gases. We build on this 1% CO ₂ experiment by constructing five different scenarios. In the first scenario, we ramp-up the CO ₂ atmospheric concentration by 1% yr −1 starting from the initial concentration (286 ppmv) and finishing at four times that concentration (1144 ppmv). Four ramp-down scenarios have been branched at different points along this increasing concentration. The CO ₂ concentration is decreased at 1% yr −1 starting at four different concentration levels (4 × CO ₂, 3 × CO ₂, 2 × CO ₂ and 1.5 × CO ₂), giving a range of radiative forcing increases of up to around 7.5 Wm −2 covering much of the range spanned by the new policy-relevant simulations for the next IPCC assessment (Moss et al 2010). Several techniques have been proposed to remove carbon dioxide from the atmosphere, either through large-scale biomass growth coupled with carbon sequestration, modification of the ocean chemical composition, acceleration of the carbonate cycle or direct air capture. The potential for successful carbon dioxide removal using these techniques is uncertain, and the current proposed methods cannot achieve the level required to sustain a 1% decrease per year in atmospheric CO ₂ concentration. However it is not uncommon to investigate unusual climate scenarios with more simple climate models. Performing such peak-and-decline scenarios with a full Earth System model is a good test of whether the simple models have the right parametrizations to operate under conditions of decreasing concentrations of greenhouse gases.

It should be noted that because the CO ₂ atmospheric concentration is prescribed, the C budget is not closed. The CO ₂ fluxes between the atmosphere and the ocean and between the atmosphere and the land surface are only diagnostics in these simulations. Nonetheless they can be used to understand how the carbon-climate feedback operates as described in Hibbard et al ( 2007) and Jones et al ( 2011). It is also recognized that the ramp-down part of the scenario is unrealistic as it would necessitate very large negative C emissions as discussed further below.

3.1. Atmospheric component

GMST increases at a near-constant rate when CO ₂ concentration increases exponentially and is about 5.5 °C above the pre-industrial value at the time of CO ₂ quadrupling (figure 1). When the CO ₂ concentration starts to decrease, the temperature change reverses immediately over land but with a time lag over the ocean, as found previously for lower rates of greenhouse gas reduction. We find that the larger the CO ₂ peak concentration, the longer is this time lag (it is up to 20 yr when CO ₂ concentration peaks at four times the pre-industrial value). For the 2 × CO ₂ ramp-up and ramp-down, the time lag is about 10 yr and is consistent with that found by Samanta et al ( 2010). The GMST change remains 0.5-1.2 °C above its initial value by the time CO ₂ returns to its pre-industrial value (figure 1(b)). Since many components of the climate system are driven by surface temperature, we present further changes in the system as a function of the GMST but we recognize that some variables such as precipitation and continental ecosystems also respond to the CO ₂ concentration (Cao et al 2011, Andrews et al 2010). We try to identify critical CO ₂ concentrations and GMST changes beyond which the changes in some components either become irreversible or relax to their pre-industrial state on a much longer timescale.

The variations in global-mean precipitation are dominated by changes over the oceans, while land precipitation changes are noisy and less systematic (figures 2(a) and (b)). The global-mean precipitation shows a clear hysteresis behaviour in all four experiments, confirming earlier findings using the HadCM3 model (Wu et al 2010, Cao et al 2011). For a given GMST change, precipitation is also greater on the ramp-down CO ₂ pathway than on the ramp-up path. Two explanations for this phenomenon have been provided in previous studies. It has been shown that the precipitation response to an increase in CO ₂ atmospheric concentration can be decomposed into a (positive) slow response proportional to surface temperature change and a (negative) fast adjustment to the CO ₂ radiative forcing (Andrews et al 2010, Cao et al 2011). The hysteresis is due to the decoupling between the two terms that occurs during the ramp-down phase. It is also possible to explain the hysteresis as a response to a changing imbalance in the ocean surface energy budget (Wu et al 2010). Preference for one or the other explanation depends on whether one considers the hydrological cycle to respond to the atmospheric or surface heat budget. It is interesting that precipitation extremes (measured here as the land average of the local daily maximum precipitation rate in a year) show no hysteresis, pointing to a potentially higher degree of reversibility for hydrological climate impacts (figure 2(c)).

Clouds also respond to the CO ₂ forcing, with high-level cloud increasing and low- and mid-level cloud decreasing during the ramp-up phase, and a general tendency to opposite behaviour as the CO ₂ is reduced (figures 2(d)-(f)). Such changes in the global-mean cloud amounts are well established (Mitchell and Ingram 1992) and have also been confirmed in more recent studies (Ringer et al 2006). Examination of the radiative impact of the individual cloud types (not shown) indicates a high degree of compensation between the net effects of the changes in high- and middle-level clouds in both the ramp-up and ramp-down phases. The radiative impact of the changes in low-level cloud is small because it primarily results from changes in optically thin clouds and smaller changes of opposite sign in optically thicker clouds. An interesting feature of the ramp-down phase is the lagged response of low-level clouds which show a small hysteresis effect. Further examination reveals that this is primarily an oceanic effect, depending, like the precipitation, on the balance between fast and slow responses and also on the geographical pattern of the SST change. In contrast, over land changes in all cloud types reverse almost immediately with surface temperature when CO ₂ is decreased.

3.2. Oceanic component

Ocean heat uptake relates closely to the thermal expansion component of sea-level rise, which may dominate 21st century sea level increases (Meehl et al 2007). By the time the CO ₂ concentration has risen to four times pre-industrial levels the model projects the ocean heat content (figure 2(g)) to have increased by 3 × 10 ²⁴ J, with a thermal expansion of about 40 cm. After the forcing declines from 4 × CO ₂ the heat content continues to increase by a further 60% over the next century. The time between the peaks in forcing and ocean heat uptake varies strongly with the magnitude of the peak forcing, ranging from approximately 25 yr (1.5 × CO ₂) to a century (4 × CO ₂). This shows that only a rapid reduction in radiative forcing might be able to limit and reduce the thermal expansion component of sea-level rise before some of the most severe coastal impacts are realized. The annual mean Arctic and Antarctic sea-ice covers are entirely reversible up to 4 × CO ₂; the recovery has a 50 yr lag over CO ₂ but no lag over the GMST in line with earlier findings (Yoshida et al 2005, Samanta et al 2010, Tietsche et al 2011, see figure 2(j)). This is in contrast with the results from a simple model used by Abbot et al ( 2011) who found that cloud and heat transport feedbacks could lead to bifurcations in the state of Arctic sea-ice, which would lead to possible hysteresis effects in the ramp-up and ramp-down scenario we consider. The Atlantic meridional overturning circulation (AMOC) seems to be reversible in all four cases, although there is a lag of 2-3 decades in the 3 × and 4 × CO ₂ ramp-down experiments. For these two cases, the AMOC weakening trend continues to undershoot further after CO ₂ ramp-down before the recovery starts. In all cases, the AMOC recovers to its normal strength during the later stabilization period after CO ₂ returns to the pre-industrial level (not shown).

Unlike the ocean heat content, the ocean carbon content shows a decrease soon after the forcing reverses (figure 2(h)). To first order, both the ocean heat and carbon contents are governed by atmosphere-ocean gradients and the exchange between the mixed layer and the deep ocean. Whilst throughout these simulations the surface ocean is colder than the atmosphere by the mixing up of cold water from depth, until atmospheric CO ₂ concentrations become very high, mixing with the deep ocean is always enriching the surface waters in CO ₂. Deep mixing is therefore acting to increase the ocean-atmosphere temperature gradient, delaying the turnover in air-sea heat flux until towards the end of our simulations, but decreases the ocean-atmosphere CO ₂ gradient, causing the ocean to become a source of CO ₂ to the atmosphere only a few decades after the ramp-down starts. This results in a timescale for equilibrating ocean heat in the ramp-down that is much longer than that for equilibrating the CO ₂, at least in the ocean mixed layer. The ocean surface pH responds very quickly to atmospheric concentrations and is almost totally reversible in the global mean. However some of the impact of ocean acidification on marine ecosystems, for example on calcification (Riebesell et al 2000, Iglesias-Rodriguez et al 2008), may not be reversible in the same way, and may even feed back to limit the pH reversibility through changes in alkalinity not considered in our simulations. Deeper ocean pH and changes in the depth of the lysocline do not experience the reversibility experienced in the surface ocean.

Major nutrient concentrations simulated in the surface ocean waters decreases almost linearly under the increasing greenhouse gas forcing. Nutrients available for photosynthesis (i.e., those at the surface ocean where light can penetrate) are expected to decrease under global warming (Behrenfeld 2006), and this occurs in the model as the ocean warms and stratifies, slowing the replenishment of nutrients from depth. An unexpected feature of these experiments is that, despite the mixed layer thickness in most of the ocean recovering in line with the removal of heat from the surface ocean, the globally averaged recovery of surface nutrient concentrations is very slow (figure 2(i)). The limited nutrient recovery results from a significant (>century) lag in the recovery of freshwater-driven stratification over much of the Southern Ocean, preventing upwelling of nutrient-rich waters from depth. This effect could have long-lasting consequences for marine productivity. The persistence of a low-salinity lid across much of the Southern Ocean can be understood as a simple function of the time lag between supply of freshwater through precipitation and removal of that water by mixing. Even if the high-latitude precipitation response to our forcing were to be perfectly reversible and simply scale with that forcing, since the salinity at any point in time integrates the changing freshwater flux over some interval prior to that point in time, and since the preceding precipitation is different to the present-day one during the ramp-up and ramp-down periods, a lag in surface salinity, independent of the complexities of the ocean physical circulation, is to be expected.

3.3. Terrestrial component

Soil moisture changes differ by depth. Moisture changes in the top (10 cm) soil layer responds linearly to changes and are completely reversible. Moisture changes in the bottom (1-3 m) soil layer shows much more of a lag when responding back to a decrease in CO ₂ concentration because of the inertia associated with the deep soil hydrology. We calculated a drought diagnostic from the anomaly of soil moisture in the top 1 m of the soil. A soil moisture anomaly threshold was created for each grid cell based on the 20th percentile distribution of monthly soil moisture anomalies for the first 10 yr of the simulation. Any time the soil moisture anomaly falls below this threshold the grid cell is assumed to be in drought for that month. Figure 2(k) shows the proportion of the land surface that is in drought at any particular year (it is 20% on average during the first 10 yr of the simulation). The hysteresis arises because it takes time for the changes in the forcing meteorology to impact the soil moisture down to a depth of 1 m. The permafrost fraction over land (diagnosed from monthly soil temperatures) shows a hysteresis effect as a function of the GMST, with approximately 20% less permafrost area in the ramp-down than in the ramp-up experiment figure 2(l). Although permafrost extent is eventually fully reversible, any loss of organic carbon during the time thawed would be effectively irreversible as this has accumulated over many millennia. The various vegetation types in the model exhibit different behaviour when the atmospheric CO ₂ concentration changes. Changes in vegetation fraction are not linear with temperature because they are driven by their carbon balance which depends on both climate and CO ₂ fertilization (Gregory et al 2009, Denman et al 2007) and competition between vegetation types. When the CO ₂ concentration increases, the bare soil fraction decreases while trees, shrub and grass fractions increase globally. Gross primary production (GPP) over land responds linearly with the logarithm of CO ₂ in the ramping up phase. However both vegetation and soils continue to take up carbon many years after the atmospheric CO ₂ concentration is diminished (figures 2(m) and (n)). For vegetation carbon, this is because of the long response time associated with vegetation competition. Trees continue to increase in the NH high latitudes after the peak in CO ₂ and temperature and this overwhelms the decrease in the fertilization effect. For soil carbon, this is because of the long lag between the increase in soil carbon pools and the increase in heterotrophic respiration.

3.4. Further discussion on the carbon cycle

Figure 3 shows the time-latitude Hovmöller diagrams of surface pH, surface nutrient concentration, vegetation carbon and soil carbon. There is a small hysteresis in pH (figure 3(a)). In the Arctic for CO ₂ concentrations of 300-400 ppmv (roughly the first and last 40 yr), pH is on average 0.06 smaller in the ramp-down phase. While the global-mean surface ocean pH is almost totally reversible, regional variations are to be expected because of changes in sea-ice and freshwater budget as underlined by Steinacher et al ( 2009). Much of the global-mean reduction in surface nutrient concentration seen in figure 2(i) is due to large reductions seen at high latitudes (figure 3(b)) caused by fresher, more stable, surface waters. At lower latitudes the zonal signal is dominated by reductions in upwelling regions. Figures 3(c) and (d) show the terrestrial carbon stores. In the tropics the terrestrial carbon stores are fully reversible within the timescale of the simulation. The timescale of reversibility is longer at higher latitudes and these regions are mostly responsible for the hysteresis seen in figures 2(m) and (n). Carbon store changes at lower latitudes are caused by increases/decreases in the carbon density of forests, while at higher latitudes the increase is caused by an increase in forest area. Soil carbon peaks before vegetation carbon, because soil carbon varies with NPP which is closely linked to the atmospheric CO ₂ concentration, while the peak in vegetation carbon is delayed by the slow expansion in the area of forest.

Figure 4 shows the positive and negative emissions (GtC yr −1) necessary to close the CO ₂ atmospheric budget in the ramp-up and ramp-down phases. It can be observed that the peak decrease is only about half the peak increase. This is because there is still some natural uptake after the peak so the negative emissions are offset by some continued terrestrial and oceanic increase. The ramp-down negative emissions are almost flat (especially when ramping down from 4 × CO ₂). This is because the offsetting from natural uptake lessens and then reverses while the effort to bring atmospheric concentrations down keeps decreasing as the 1% profile levels off (i.e., the absolute rate of ramp-down decreases in time). The cumulative emissions amount to 3250 GtC to get to the 4 × CO ₂ peak. The atmospheric increase is about 1820 GtC, which corresponds to an average airborne fraction of 56%. On the way down, cumulative negative emissions are about − 2400 GtC so a smaller equivalent amount of CO ₂ has to be taken out than was initially introduced. A fact relevant to CDR technology is that any negative emission will be subject to an airborne fraction in the same way as positive emissions. During the ramp-down phase, the average airborne fraction is 76%, which is significantly greater than during the ramp-up phase (as the natural sinks are still responding at the beginning of the ramp-down).

We have investigated hysteresis and irreversibility in the Earth system using a highly idealized experiment in which the atmospheric CO ₂ concentration is first ramped up and then ramped back down to its initial level. Although the scenario is unrealistic because of the requirement for large negative C emissions in the ramp-down phase, it is useful to investigate hysteresis and irreversibility in the Earth system and can provide insight into a hypothetical scenario of carbon dioxide removal. In summary only the ocean surface pH responds almost immediately to the atmospheric CO ₂ concentrations in our experiments. Other quantities exhibit some time lag relative to the change in CO ₂ and most also exhibit a lag relative to the GMST, which we describe as a hysteresis behaviour in CO ₂ or GMST space. For certain quantities, such as precipitation, the hysteresis in GMST space occurs as a response to asynchronous variations in CO ₂ and GMST. For ocean heat content or permafrost area, the hysteresis arises because the quantity is not in equilibrium with GMST and depends on processes operating on longer timescales. Longer experiments would be required to discriminate hysteresis phenomena due to inertia from those reflecting a bi-stability or multiple equilibria in the system.

The most surprising responses are those in low-level clouds and ocean stratification in the Southern Ocean, which both exhibit hysteresis on timescales longer than expected. We did not see evidence of critical thresholds in these simulations, although some of the hysteresis phenomena become more apparent above 2 × CO ₂ or 3 × CO ₂. We summarize in table 1 potential implications of our results for climate impact studies. Overall it appears that the most significant hysteresis in the HadGEM2-ES model is for variables relating to terrestrial and marine ecosystems. In contrast physical changes in the model show little hysteresis (except for sea-level rise). The latter is consistent with the findings from Samanta et al ( 2010) who found that physical climate parameters return to their initial values soon after the CO ₂ concentration does in a similar 2 × CO ₂ ramp-up and ramp-down experiment.

Table 1. Qualitative interpretation of our results for the reversibility of key climate impacts and feedbacks in ramp-up and ramp-down experiments.

Climate impacts

Degree of reversibility in ramp-down experiments

Remarks

Land surface

Land surface temperatures reverse quicker than ocean surface temperature although permafrost shows delay in recovery

Heat generation due to decomposition of organic matter in permafrost (Khvorostyanov et al 2008), thermokarst development and loss of ground ice (Schuur et al 2008, O'Connor et al 2010) may delay permafrost recovery further. Despite the physical permafrost extent being reversible, any organic carbon lost while thawed will not be

Precipitation

Global-mean precipitation shows hysteresis but land precipitation and extreme precipitation do not

Arctic sea-ice

Arctic sea-ice cover shows a high degree of reversibility in terms of the GMST

Sea-level rise

Sea-level rise from thermal expansion shows very-long timescale inertia. Only in the 1.5 × CO ₂ ramp-down experiment does sea level stabilize and decrease

Other components to sea-level rise may cause further irreversibility

Marine ecosystems

The model shows evidence of long-lasting impact on nutrient availability in the Southern Ocean

Effects of acidification on marine ecosystems may lead to further irreversible changes

Continental ecosystems

Vegetation dynamics can induce long timescale inertia in the system which can offset the decreasing fertilization effect

Nutrient availability may limit ecosystem response to climate change. Changes in fire regime, not modelled here, may trigger rapid ecosystem changes and introduce long lags in recovery

Carbon cycle feedbacks

Ocean carbon storage responds more quickly to ramp-down than ocean heat uptake, and rapidly releases stored carbon back to atmosphere. Land carbon storage continues to increase slowly immediately after start of ramp-down and shows a significant hysteresis lag due to the inertia of vegetation and long-lived soil carbon pools

This has implications for projections of future CO ₂ under overshoot or negative emissions scenarios such as RCP2.6

It is common to parameterize climate impacts in integrated assessment models and simple climate models as a function of the global-mean surface temperature change. While such a parametrization may be justified by the large uncertainties in damage cost functions and the monotonous and phased increase in CO ₂ concentration, surface temperature and climate impacts in most scenarios, our results bring evidence that climate impacts cannot be parameterized as a function of GMST alone in unconventional scenarios such as those with CO ₂ overshooting. A geoengineering scenario where the CO ₂ atmospheric concentration peaks at levels much higher than today's before decreasing rapidly may experience delayed climate impacts. Determining more precisely which impacts may be irreversible will require even more complex representation of the Earth system with a focus on components which are potential sources of irreversibility, such as ice sheets, soil carbon in permafrost regions and terrestrial and oceanic ecosystem biodiversity.

This work was funded by the Joint DECC/Defra Met Office Hadley Centre Climate Programme (GA01101) and by the European Commission's 7th Framework programme, under grant agreement number 226520, COMBINE project, and grant agreement number 282672, EMBRACE project. We thank two anonymous reviewers for their useful comments.

# data[].attributes.attachment_link.title
Reversibility in an Earth System model in response to CO2 concentration changes

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1 Met Office Hadley Centre, FitzRoy Road, Exeter, UK 2 Present address: Laboratoire de Météorologie Dynamique, IPSL, CNRS/UPMC, Paris, France. 3 Present address: EUMETSAT, Darmstadt, Germany.

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https://www.nhm.ac.uk/discover/quick-questions/how-does-carbon-dioxide-increase-global-temperature.html
위 글을 보면 태양 에너지가 지구 표면을 통과하여 흡수하는데 그 일부는 대기로 빠져나가는데 지구는 빠져나가는것을 방지하는 역할으로 그 갇힌 열 에너지는 지구 표면 기온을 증가시킨다고 한다.

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Carbon dioxide (CO ₂) is a greenhouse gas. This means that it causes an effect like the glass in a greenhouse, trapping heat and warming up the inside. This effect is important: without the CO ₂ that naturally exists in the atmosphere, Earth might be too cold to support human life. However, the atmosphere is very sensitive to changing levels of CO ₂. Even though this gas makes up less than 0.1% of the atmosphere, it can have a huge effect on how much heat the planet's surface retains.

When energy from the Sun reaches the top of our atmosphere, most of it passes through to Earth's surface, where it is absorbed. Some of this energy is re-emitted, heading back towards space. At this stage, it interacts with molecules of CO ₂ in a way that prevents some of it from escaping Earth's atmosphere. The trapped heat energy leads to increased average global surface air temperatures.

One reason carbon dioxide has such a big impact on global temperatures is that hotter air can hold more water vapour. Water vapour is itself a greenhouse gas, which further enhances the greenhouse effect.

While the presence of carbon dioxide in Earth's atmosphere is natural, the rising levels since the Industrial Revolution in the 1800s are due to human activities, primarily the burning of fossil fuels such as coal and oil.

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How does carbon dioxide increase Earth's temperature?

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Carbon dioxide (CO2) is a greenhouse gas. Find out what this means and why carbon dioxide has such a big impact on global temperatures.

# data[].attributes.body
https://padlet.com/yim26581/3q80ro43fie1srg9/wish/2312878196

# data[].attributes.body
https://m.search.naver.com/p/crd/rd?m=1&px=245&py=206&sx=245&sy=206&p=hzZikdqVWusss5sYAnKssssstY8-025212&q=%EB%82%A8%EA%B7%B9+%EB%B9%99%ED%95%98+%EB%85%B9%EB%8A%94&ie=utf8&rev=1&ssc=tab.m.all&f=m&w=m&s=26gOZrYKEpvEYtXzTeQTeA%3D%3D&time=1664162162348&abt=%5B%7B%22eid%22%3A%22SHOP-MAB%22%2C%22vid%22%3A%229%22%7D%5D&a=kdc_gnl.child&r=1&i=8816ca20_0000000020d9015bae36dd0f&u=https%3A%2F%2Fterms.naver.com%2Fentry.naver%3FdocId%3D3582814%26cid%3D58583%26categoryId%3D59179&cr=1

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[더오래]북극곰 개체수 3만 마리…국내 동물원엔 왜 없을까 | 중앙일보

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다른 사냥방법은 쉬려 얼음판 위로 나온 바다표범을 습격하거나 번식을 위해 눈 속에 둥지를 만든 암컷 바다표범을 잡아먹기도 한다. 짝짓기는 바다표범이 사냥지역에 최대로 모여있을 때인 4~5월에 바다의 얼음 위에서 행해진다. 북극곰의 생활터전인 바다의 얼음판이 얇아지고 없어지면 먹이인 바다표범의 사냥이 어려워

# data[].attributes.body
https://climate.nasa.gov/vital-signs/sea-level/

# data[].attributes.attachment_link.provider_name
Climate Change: Vital Signs of the Planet

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101 (± 4.0) mm

This is the "uncertainty margin," or the range from the mean (average) within which there is a high probability that the true number resides. For example, when we say global sea level has risen 101 mm +/- 4 mm, the true value has a high probability of being between 97 and 105 mm. The uncertainty margin exists both because of sea level variability (sea level above the first point in the time series) in the ocean and the accuracy with which we measure the individual values.

Key Takeaway:

Global sea levels are rising as a result of human-caused global warming, with recent rates being unprecedented over the past 2,500-plus years.

Sea level rise is caused primarily by two factors related to global warming: the added water from melting ice sheets and glaciers, and the expansion of seawater as it warms. The first graph tracks the change in global sea level since 1993, as observed by satellites.

The second graph, which is from coastal tide gauge and satellite data, shows how much sea level changed from about 1900 to 2018. Items with pluses (+) are factors that cause global sea level to increase, while minuses (-) are what cause sea level to decrease. These items are displayed at the time they were affecting sea level.

The data shown are the latest available, with a four- to five-month delay needed for processing.

* You now need to create an Earthdata account to access NASA's sea level data. Register here for free. Once logged in, click the "download data" button on this page to access the data.
NASA Sea Level Change

# data[].attributes.attachment_link.description
Vital Signs of the Planet: Global Climate Change and Global Warming. Current news and data streams about global warming and climate change from NASA.

# data[].attributes.attachment_link.provider_name
Climate Change: Vital Signs of the Planet

# data[].attributes.attachment_link.readable_text
101 (± 4.0) mm

This is the "uncertainty margin," or the range from the mean (average) within which there is a high probability that the true number resides. For example, when we say global sea level has risen 101 mm +/- 4 mm, the true value has a high probability of being between 97 and 105 mm. The uncertainty margin exists both because of sea level variability (sea level above the first point in the time series) in the ocean and the accuracy with which we measure the individual values.

Key Takeaway:

Global sea levels are rising as a result of human-caused global warming, with recent rates being unprecedented over the past 2,500-plus years.

Sea level rise is caused primarily by two factors related to global warming: the added water from melting ice sheets and glaciers, and the expansion of seawater as it warms. The first graph tracks the change in global sea level since 1993, as observed by satellites.

The second graph, which is from coastal tide gauge and satellite data, shows how much sea level changed from about 1900 to 2018. Items with pluses (+) are factors that cause global sea level to increase, while minuses (-) are what cause sea level to decrease. These items are displayed at the time they were affecting sea level.

The data shown are the latest available, with a four- to five-month delay needed for processing.

* You now need to create an Earthdata account to access NASA's sea level data. Register here for free. Once logged in, click the "download data" button on this page to access the data.
NASA Sea Level Change

# data[].attributes.attachment_link.description
Vital Signs of the Planet: Global Climate Change and Global Warming. Current news and data streams about global warming and climate change from NASA.

# data[].attributes.body
https://www.arcticwwf.org/wildlife/polar-bear/polar-bear-population/

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Before 1973

Polar bears are an integral part of the Arctic ecosystem and the food web for Indigenous Peoples - who have hunted polar bears sustainably for millennia. But, beginning in the 1700s, large-scale hunting by European, Russian and North American hunters and trappers took place, raising concerns about the future survival of polar bears. Unregulated commercial and recreational hunting continued until the 1970s.

1973

Canada, the United States, Denmark, Norway and the former USSR signed the International Agreement on the Conservation of Polar Bears and their Habitat, strictly regulating commercial hunting.

The US Government classified the Polar Bear under its Endangered Species Act (ESA).
2005
The polar bear was upgraded from Least Concern to Vulnerable by the the IUCN Polar Bear Specialist Group.
2013
Ministers and other leaders from the five polar bear range states met in Moscow for the first International Forum on Polar Bear Conservation. The leaders made significant commitments to address issues of polar bear habitat, research and trade. This event was supported by WWF.

Today

Today, polar bears are among the few large carnivores that are still found in roughly their original habitat and range-and in some places, in roughly their natural numbers.

Although most of the world's 19 populations have returned to healthy numbers, there are differences between them. Some are stable, some seem to be increasing, and some are decreasing due to various pressures.

Status of the polar bear populations
Updated 2021 with data from the IUCN Polar Bear Specialists Group:

3 populations are in decline
2 populations are increasing
4 populations are stable
10 populations are data-deficient (information missing or outdated)

In the future

By 2040, scientists predict that only a fringe of ice will remain in Northeast Canada and Northern Greenland when all other large areas of summer ice are gone. This "Last Ice Area" is likely to become important for polar bears and other life that depends on ice.

A projection of sea ice in the archipelago, supported by WWF, shows that much of the region is facing significant ice loss in the coming decades - with potentially serious consequences for polar bears.
Global polar bear numbers are projected to decline by 30% by 2050.

# data[].attributes.attachment_link.description
How many polar bears are there? See current polar bear populations, IUCN Red List status by country and timeline of polar bear conservation.

# data[].attributes.body
https://m.dongascience.com/news.php?idx=52605
위 글에는 남극 빙하 면적이 관측 이래 최저 면적을 기록했다고 적혀있다.

https://www.google.co.kr/amp/s/amp.seoul.co.kr/m/20220906500090
위 글에도 마찬가지로 적혀있다.

https://www.sciencetimes.co.kr/news/%EB%82%A8%EA%B7%B9-%EB%B9%99%ED%95%98-%EA%B8%B0%EC%A1%B4-%EC%98%88%EC%B8%A1%EB%B3%B4%EB%8B%A4-%EB%8D%94-%EC%9C%84%ED%97%98%ED%95%B4/
위의 글에는 남극 빙하가 녹는 속도가 마지막 빙하기보다 빨라졌다고 주장하며 점점 빨리질 수도 있다고 경고한다.

https://m.blog.naver.com/kma_131/222110159111
여기에는 남극 빙하가 녹으면 안 되는 이유도 있다.

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남극의 해빙 면적 측정이 시작된 지 40년 만에 최저면적을 기록했다. 전문가들은 남극 해빙이 1990년대보다 현재 3배나 빠르게 줄고 있으며, 전 세계 해수면 상승을 유발하고 있다고 분석했다.

미국 자연환경 분야 온라인매체인 어스닷컴에 따르면 미국 국립빙설자료센터(NSIDC)의 예비데이터에서 남극의 해빙면적이 지난 22일 약 194만1000㎢로 나타나며 역대 최저기록을 경신했다. 다음날인 23일에는 이보다 더 떨어져 193만7000㎢까지 떨어진 상태다. 이전 최저기록은 2017년 3월 3일 211만㎢였다.

남극의 해빙은 계절에 따라 늘었다가 줄어드는데, 남극의 여름인 2~3월에 가장 축소된다.

북극은 해빙의 빠르게 줄었지만, 상대적으로 남극의 해빙은 크게 변동하지 않았다. 그러나 2016년 해빙이 급격히 줄어든 이후 계속해서 평균보다 낮은 수준을 유지하고 있다.

테드 스캄보스 미국 국립빙설자료센터 수석연구원은 어스닷컷을 통해 "남극의 해빙은 바람세기, 폭풍 빈도, 강설량, 해수온도 등 매우 많은 변수에 영향을 받는다"며 "지난 40년간 해수온도와 바람의 변화에 의해 남극의 특성이 다소 바뀐 것으로 보인다"고 설명했다.

전문가들은 남극 해빙 감소를 기후변화 영향으로 특정짓기 위해서는 지금과 같은 면적 감소 추세가 10년은 더 이어져야 한다고 설명한다. 그러나 기후변화 영향은 이미 남극대륙 곳곳에서 나타나고 있다.

가령 남극의 거대 빙하 중 하나인 스웨이츠빙하는 균열이 곳곳에 나타난 상태다. 이 빙하는 3~5년 내 붕괴돼 전 세계 엄청난 해수면 상승을 초래할 것으로 전망된다.

# data[].attributes.attachment_link.title
남극 해빙 관측이래 최저 면적 기록...전 세계 해수면 상승 경고

# data[].attributes.attachment_link.description
남극의 해빙 면적 측정이 시작된 지 40년 만에 최저면적을 기록했다. 전문가들은 남극 해빙이 1990년대보다 현재 3배나 빠르게 줄고 있으며, 전 세계 해수면 상승을 유발하고 있다고 분석했다. 미국 자연환경 분야 온라인매체인 어스닷컴에 따르면 미국 국립빙설자료센터(NSIDC)의 예비데이터에서 남극의 해빙면적이 지난 22일 약 194만1000㎢로 나타나며 역대 최저기록을 경신했다. 다음날인 23일에는 이보다 더 떨어져 193만7000㎢까지 떨어진 상태다.

# data[].attributes.body
https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature

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Earth's surface temperature has risen about 2 degrees Fahrenheit since the start of the NOAA record in 1880.

# data[].attributes.body
https://www.sciencetimes.co.kr/news/%EC%A7%80%EA%B5%AC-%ED%95%B4%EC%88%98%EB%A9%B4-%EC%83%81%EC%8A%B9-%EC%B5%9C%EC%95%85%EC%9D%98-%EC%8B%9C%EB%82%98%EB%A6%AC%EC%98%A4%EB%A1%9C-%EC%A7%84%ED%96%89-%EC%A4%91/

# data[].attributes.attachment_link.title
“지구 해수면 상승, 최악의 시나리오로 진행 중” – Sciencetimes

# data[].attributes.attachment_link.description
국내외 과학기술동향, 정책, 문화 등 과기계 이슈 정보 제공. 매주 금요일 뉴스레터 발송.

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https://www.arcticwwf.org/wildlife/polar-bear/polar-bear-population/

# data[].attributes.attachment_link.readable_text
Before 1973

Polar bears are an integral part of the Arctic ecosystem and the food web for Indigenous Peoples - who have hunted polar bears sustainably for millennia. But, beginning in the 1700s, large-scale hunting by European, Russian and North American hunters and trappers took place, raising concerns about the future survival of polar bears. Unregulated commercial and recreational hunting continued until the 1970s.

1973

Canada, the United States, Denmark, Norway and the former USSR signed the International Agreement on the Conservation of Polar Bears and their Habitat, strictly regulating commercial hunting.

The US Government classified the Polar Bear under its Endangered Species Act (ESA).
2005
The polar bear was upgraded from Least Concern to Vulnerable by the the IUCN Polar Bear Specialist Group.
2013
Ministers and other leaders from the five polar bear range states met in Moscow for the first International Forum on Polar Bear Conservation. The leaders made significant commitments to address issues of polar bear habitat, research and trade. This event was supported by WWF.

Today

Today, polar bears are among the few large carnivores that are still found in roughly their original habitat and range-and in some places, in roughly their natural numbers.

Although most of the world's 19 populations have returned to healthy numbers, there are differences between them. Some are stable, some seem to be increasing, and some are decreasing due to various pressures.

Status of the polar bear populations
Updated 2021 with data from the IUCN Polar Bear Specialists Group:

3 populations are in decline
2 populations are increasing
4 populations are stable
10 populations are data-deficient (information missing or outdated)

In the future

By 2040, scientists predict that only a fringe of ice will remain in Northeast Canada and Northern Greenland when all other large areas of summer ice are gone. This "Last Ice Area" is likely to become important for polar bears and other life that depends on ice.

A projection of sea ice in the archipelago, supported by WWF, shows that much of the region is facing significant ice loss in the coming decades - with potentially serious consequences for polar bears.
Global polar bear numbers are projected to decline by 30% by 2050.

# data[].attributes.attachment_link.description
How many polar bears are there? See current polar bear populations, IUCN Red List status by country and timeline of polar bear conservation.

# data[].attributes.attachment_link.readable_text
요약 여러 가지 환경파괴 때문에 지구의 평균 온도가 상승하는 현상.

얼마 전 TV를 보는데 북극에 대한 환경 다큐멘터리를 하고 있었어. 지구 온난화 때문에 빙하가 점점 녹아서 북극곰들이 먹이를 구할 데가 점점 없어지고 있대. 작은 빙하 위에 망연자실 앉아 있는 북극곰은 참 힘들어 보였어. 함께 TV를 보시던 엄마는 저게 다 우리 때문이라고 하셨어. 아니, 북극곰이 불쌍하기는 하지만, 북극에서 멀리 떨어져 있는 내가 뭘 잘못했다는 거지?

지구 온난화란 지구의 온도가 점점 높아져서 기후와 동식물들이 지금까지 살아왔던 생활환경이 바뀌고 있는 현상이야. 제일 큰 문제점은 남극에 있는 빙하가 점점 녹아서 바다로 흘러드는 바람에 바닷물의 높이가 점점 높아지고 있다는 거야.

가라앉는 섬들이 많아지고 있어
남태평양의 조그만 섬나라 투발루는 해수면 아래로 가라앉고 있는 나라로 유명해. 산호초와 야자수, 하얀 백사장으로 아름다운 경치를 자랑하지만 해발고도가 낮거든. 투발루는 바닷물이 점점 차올라 사람이 살 곳이 좁아들고 있어. 지구가 온난화되면서 모든 곳이 바닷물이 차오르는 속도가 빨라지고 있어. 남태평양의 투발루뿐 아니라 그 일대의 여러 화산섬, 태평양 가운데에 있는 하와이와 우리나라의 제주도, 울릉도, 독도와 같은 화산섬은 바다 아래로 가라앉고 있어.

땅 속의 마그마가 땅 위로 올라와 용암이 되어 흐르면서 화산섬을 만들지.
용암이 식어서 만든 돌을 현무암이라고 하는데, 이 암석은 돌하르방처럼 구멍이 숭숭 뚫려 있거나 돌 안에 미세한 공간이 많이 있어.
엄청난 힘으로 누르면 이들 공간이 메워지면서 부피가 줄어들기 때문에 화산섬은 세월이 지나면 점차 가라앉게 되는 거야.

독도가 가라앉고 있어
1년에 1㎝씩 가라앉는다면 1m가 가라앉으려면 100년이 걸리지. 10m가 가라앉으려면 1,000년이나 걸리니까 독도가 사라지려면 수만 년이 필요할 거야. 하와이는 화산활동으로 지금도 섬이 만들어지고 있지만 북서쪽으로 이어진 섬들은 점차 낮아지고 있어. 더 북서쪽으로 가면 마침내 섬들은 보이지 않고 바다 밑에 산처럼 높은 지형을 발견할 수 있지. 독도도 처음에는 울릉도처럼 큰 섬이었지만 세월이 지나면서 가라앉아 산의 꼭대기만 물 위에 보이게 된 거야.

화산섬 주민들의 고민
아주 천천히 가라앉으니까 걱정할 것이 없다고 생각할지 모르지만 1m만 가라앉아도 문제는 심각해. 화산섬의 많은 집들이 해안가에 자리하고 있어 태풍의 피해를 걱정해야 하거든. 해안가 사람들은 보다 높은 곳으로 이주하거나 파도에 맞서 높은 방파제를 만들고 있어.

평상시에는 걱정하지 않아도 되던 파도가 태풍이 불 때는 무섭게 변해. 더구나 요즘 지구 온난화로 해수면이 높아지면서 태풍이 자주 발생하고 위력도 더욱 세지고 있어. 여기에 매년 조금씩이지만 섬이 가라앉는다고 하면 더욱 어려움이 많겠지. 제주도와 울릉도 사람들도 매년 태풍과 해일에 대한 피해를 걱정하고 있어.

투발루 사람들의 어려움
투발루 사람들은 대부분 해안가 낮은 지대에 살고 있으므로, 해수면이 1m만 상승해도 많은 주민은 살 집을 잃게 돼. 높은 곳으로 이주하고 싶어도 마땅한 땅이 없어. 가까운 섬나라도 대부분 화산섬으로 높아지는 해수면과 가라앉는 섬으로 살 집을 지을 장소가 줄어들고 있어. 가라앉는 화산섬을 끌어 올릴 방법은 없어. 해저에서 화산이 폭발하여 새로운 화산섬이 생기기도 하지만 새로 생긴 화산섬은 죽은 섬이나 같다고 해. 왜냐하면 화산폭발 후 수천 년은 지나야 나무와 풀이 자라고 동식물이 어우러져 사람이 살 수 있는 섬으로 변하니까.

태풍 등에 의해 해수면이 50㎝ 이상 높아지고, 높은 파도가 밀물과 겹치면 해안가 주택을 덮치게 되는 거야.

우리들의 대책
어려움에 처한 투발루 사람들을 위해 우리가 할 수 있는 일은 무엇일까? 지구 온난화의 원인은 석탄, 석유 등의 화석 연료를 과도하게 사용하면서 이산화탄소가 너무 많이 발생했기 때문이야. 그러니까 이산화탄소의 배출량을 줄여 지구 온난화로 인한 해수면 상승을 늦추거나 멈추게 해야 해. 세계 각국에서는 이산화탄소 배출량을 줄이기 위해 협약을 맺고 서로 감시하기도 해. 요즘 이야기되는 녹색성장도 이러한 운동의 하나야.

해수면 상승과 온실효과 - 지구가 점점 따뜻해지고 있어

빙하가 점점 녹고 있어
지구 표면을 100으로 본다면 바다가 약 70%고 땅이 30% 정도야. 바다가 훨씬 넓지? 그런데 땅의 약 10% 정도가 빙하로 덮여 있어. 지구가 따뜻해지면 빙하가 녹게 되고, 녹은 빙하의 물은 바다로 들어가 해수면을 높아지게 해. 해수면이 높아진다는 것은 그만큼 바다가 넓고 더 깊어진다는 거겠지? 만약 빙하의 높이가 1m 낮아진다면 해수면은 3㎝가 높아지게 된대. 수년간 지구의 빙하는 1m 이상 낮아진 것으로 알려지고 있어. 녹는 속도도 점점 빨라지고 있지.

주범은 이산화탄소야
지구가 따뜻해지는 원인을 여러 가지로 생각하고 있지만, 가장 큰 요인은 산업의 발달로 화석연료를 많이 사용하기 때문이라고 해. 화석연료를 사용할 때 나오는 이산화탄소가 지구를 감싸면서 지구 온도를 점점 높이고 있는 거야. 이것을 온실효과라고 해. 예를 들어 온실은 유리로 되어 있어 태양빛이 잘 들어와. 들어온 태양 빛은 온실 안을 덥게 하는데, 온실 안의 물체가 내뿜는 열은 유리에 막혀 밖으로 나가지 못하므로 온실 안이 점점 따뜻해지는 거지.

자, 이제 지구를 거대한 온실이라고 생각해 봐. 평소에 지구는 태양으로부터 에너지를 흡수하여 사용한 다음, 남는 에너지는 지구 밖으로 내보내 온도를 유지하고 있어. 태양에서 오는 에너지는 우리가 보는 빛이므로 대기를 잘 통과하여 지구의 여러 물체에 흡수되어 따뜻하게 되는 거야. 따뜻해진 지구는 적외선이라는 빛을 방출해.

이 적외선 에너지는 지구 밖으로 빠져나가지만 일부는 대기 중에 있는 이산화탄소가 에너지를 잡아두는 역할을 해. 그래서 지구 밖으로 나가지 못한 적외선 에너지가 지구의 온도를 높아지게 하는 거지. 그런데 예전에 비해 이산화탄소의 층이 점점 두꺼워지고 넓어지니까 문제가 되는 거야. 즉 지구라는 온실의 유리벽이 점점 두꺼워지고 있는 거지.

태양광선이 대기를 통과하는데 일부는 지구와 대기에서 반사되어 나가고,
일부는 지구에 있는 온실가스(이산화탄소 등)에 흡수되어 지구 지표면을 뜨겁게 하는 거야.

지구 온난화가 한반도에 어떤 영향을 미칠지 설명해 보자.
지구 온난화란 일시적으로 기온이 오르는 현상이 아니라 꾸준히 장기적으로 지구의 온도가 올라, 많은 부분에 영향을 주고 변화를 초래하여 문제가 되는 현상이라고 배웠어. 전 세계가 지구 온난화에 민감하게 반응하고 있는데, 지구 온난화가 점점 심해지면 우리나라는 어떤 영향을 받을지, 그리고 우리는 어떻게 대처해야 할지에 대해 고민해 보자.

지구 온난화로 인해 변화된 것들이 무엇이 있는지 생각해 봤어요. 최근 한반도는 여름철 집중호우와 극심한 가뭄, 이상 고온 현상 등으로 예측할 수 없는 기후변화를 겪고 있어요. 이는 지구 온난화와 무관하지 않다고 해요. 지구 온난화가 심화되면 한반도는 아열대성 기후가 될 거예요. 작물 재배기간이 늘어나고 고온을 요구하는 작물은 더 많이 수확할 수 있지만, 반대로 저온에서 생산하는 농산물은 생산량이 줄어들겠지요.

결국에는 지구 온난화로 강수량이 불규칙해지니 물을 제때 확보할 수 없어서 오히려 농업에 부정적인 영향을 가져올 수 있다고 해요. 또 지구 온난화는 이산화탄소량이 많아지는 환경을 만들어 생물 다양성을 위협할 수 있어요. 동식물은 산소를 통해 숨을 쉬고 에너지를 확보하는데, 산소가 적어지면 영양이 부족해지고, 이로 인해 환경에 적응하지 못한 생물들은 사라질지도 몰라요. 우리나라에 살던 많은 생물종이 멸종될까 우려돼요.

저는 지구 온난화를 막을 해결책으로 어떤 것이 있는지 알아 봤어요. 먼저 온실가스를 줄이는 방법을 들 수 있어요. 지금처럼 온실가스를 대량 배출하는 에너지 사용기기나 산업구조를 고에너지 효율, 저탄소 배출기기로 대체해 나가야 해요. 한편으로 태양, 풍력, 수소 및 해양 에너지, 쓰레기 재활용을 통한 새로운 에너지를 적극 개발해야 하고, 국민 개개인도 에너지를 낭비하지 않기 위해 노력해야 해요.

국민 스스로가 자가용보다는 대중교통 이용하기, 물 아껴 쓰기, 사용하지 않는 콘센트 빼놓기, 불필요한 불끄기 같은 사소한 실천에서부터 얼마든지 시작할 수 있어요. 솔직히 지구 온난화에 대한 위험성과 이산화탄소 사용량을 줄여야 한다는 얘기는 많지만, 대책 마련이나 행동으로까지는 이어지지 못하고 있어 아쉬워요. 우리나라가 지구 온난화 문제에 앞장서는 본보기가 되면 좋겠어요.

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여러 가지 환경파괴 때문에 지구의 평균 온도가 상승하는 현상. 얼마 전 TV를 보는데 북극에 대한 환경 다큐멘터리를 하고 있었어. 지구 온난화 때문에 빙하가 점점 녹아서 북극곰들이 먹이를 구할 데가 점점 없어지고 있대. 작은 빙하 위에 망연자실 앉아 있는 북극곰은 참 힘들어 보였어. 함께 TV를 보시던 엄마는 저게 다 우리 때문이라고 하셨어.

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Based on the annual report from NOAA's Global Monitoring Lab, global average atmospheric carbon dioxide was 417.06 parts per million ("ppm" for short) in 2022, setting a new record high. The increase between 2021 and 2022 was 2.13 ppm-the 11 th year in a row where the amount of carbon dioxide in the atmosphere increased by more than 2 ppm. At Mauna Loa Observatory in Hawaii, where the modern carbon dioxide record began in 1958, the annual average carbon dioxide in 2022 was 418.56.

Carbon dioxide concentrations are rising mostly because of the fossil fuels that people are burning for energy. Fossil fuels like coal and oil contain carbon that plants pulled out of the atmosphere through photosynthesis over many millions of years; we are returning that carbon to the atmosphere in just a few hundred. Since the middle of the 20 th century, annual emissions from burning fossil fuels have increased every decade, from close to 11 billion tons of carbon dioxide per year in the 1960s to an estimated 36.6 billion tons in 2022 according to the Global Carbon Budget 2022.

Carbon cycle experts estimate that natural "sinks"-processes that remove carbon from the atmosphere-on land and in the ocean absorbed the equivalent of about half of the carbon dioxide we emitted each year in the 2011-2020 decade. Because we put more carbon dioxide into the atmosphere than natural sinks can remove, the total amount of carbon dioxide in the atmosphere increases every year.

The more we overshoot what natural processes can remove in a given year, the faster the atmospheric concentration of carbon dioxide rises. In the 1960s, the global growth rate of atmospheric carbon dioxide was roughly 0.8± 0.1 ppm per year. Over the next half century, the annual growth rate tripled, reaching 2.4 ppm per year during the 2010s. The annual rate of increase in atmospheric carbon dioxide over the past 60 years is about 100 times faster than previous natural increases, such as those that occurred at the end of the last ice age 11,000-17,000 years ago.

Why carbon dioxide matters

Carbon dioxide is Earth's most important greenhouse gas: a gas that absorbs and radiates heat. Unlike oxygen or nitrogen (which make up most of our atmosphere), greenhouse gases absorb heat radiating from the Earth's surface and re-release it in all directions-including back toward Earth's surface. Without carbon dioxide, Earth's natural greenhouse effect would be too weak to keep the average global surface temperature above freezing. By adding more carbon dioxide to the atmosphere, people are supercharging the natural greenhouse effect, causing global temperature to rise. According to observations by the NOAA Global Monitoring Lab, in 2021 carbon dioxide alone was responsible for about two-thirds of the total heating influence of all human-produced greenhouse gases.

Another reason carbon dioxide is important in the Earth system is that it dissolves into the ocean like the fizz in a can of soda. It reacts with water molecules, producing carbonic acid and lowering the ocean's pH (raising its acidity). Since the start of the Industrial Revolution, the pH of the ocean's surface waters has dropped from 8.21 to 8.10. This drop in pH is called ocean acidification.

Past and future carbon dioxide

Natural increases in carbon dioxide concentrations have periodically warmed Earth's temperature during ice age cycles over the past million years or more. The warm episodes (interglacials) began with a small increase in incoming sunlight in the Northern Hemisphere due to variations in Earth's orbit around the Sun and its axis of rotation. (For more details, see the "Milankovitch cycles and ice ages" section of our Climate change: incoming sunlight article.) That little bit of extra sunlight caused a little bit of warming. As the oceans warmed, they outgassed carbon dioxide-like a can of soda going flat in the heat of a summer day. The extra carbon dioxide in the atmosphere greatly amplified the initial, solar-driven warming.

Based on air bubbles trapped in mile-thick ice cores and other paleoclimate evidence, we know that during the ice age cycles of the past million years or so, atmospheric carbon dioxide never exceeded 300 ppm. Before the Industrial Revolution started in the mid-1700s, atmospheric carbon dioxide was 280 ppm or less.

By the time continuous observations began at Mauna Loa Volcanic Observatory in 1958, global atmospheric carbon dioxide was already 315 ppm. Carbon dioxide levels today are higher than at any point in human history. In fact, the last time atmospheric carbon dioxide amounts were this high was more than 3 million years ago, during the Mid-Pliocene Warm Period, when global surface temperature was 4.5-7.2 degrees Fahrenheit (2.5-4 degrees Celsius) warmer than during the pre-industrial era. Sea level was at least 16 feet higher than it was in 1900 and possibly as much as 82 feet higher.

If global energy demand continues to grow rapidly and we meet it mostly with fossil fuels, human emissions of carbon dioxide could reach 75 billion tons per year or more by the end of the century. Atmospheric carbon dioxide could be 800 ppm or higher-conditions not seen on Earth for close to 50 million years.

More on carbon dioxide
NOAA carbon dioxide observations Carbon cycle factsheet Carbon dioxide emissions by country over time Comparing greenhouse gases by their global warming potential Ocean acidification
References

Collins, M., R. Knutti, J. Arblaster, J.-L. Dufresne, T. Fichefet, P. Friedlingstein, X. Gao, W.J. Gutowski, T. Johns, G. Krinner, M. Shongwe, C. Tebaldi, A.J. Weaver and M. Wehner, 2013: Long-term Climate Change: Projections, Commitments and Irreversibility. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Friedlingstein, P., O'Sullivan, M., Jones, M. W., Andrew, R. M., Gregor, L., Hauck, J., Le Quéré, C., Luijkx, I. T., Olsen, A., Peters, G. P., Peters, W., Pongratz, J., Schwingshackl, C., Sitch, S., Canadell, J. G., Ciais, P., Jackson, R. B., Alin, S. R., Alkama, R., ... Zheng, B. (2022). Global Carbon Budget 2022. Earth System Science Data, 14(11), 4811-4900. https://doi.org/10.5194/essd-14-4811-2022

Lan, X., B. D. Hall, G. Dutton, J. Mühle, J. W. Elkins, and I. J. Vimont. (2022). Long-lived greenhouses gases [in State of the Climate in 2021, Chapter 2: Global Climate]. Bulletin of the American Meteorological Society, 103 (8), S81-S84. https://doi.org/10.1175/BAMS-D-22-0092.1.

Lüthi, D., M. Le Floch, B. Bereiter, T. Blunier, J.-M. Barnola, U. Siegenthaler, D. Raynaud, J. Jouzel, H. Fischer, K. Kawamura, and T.F. Stocker. (2008). High-resolution carbon dioxide concentration record 650,000-800,000 years before present. Nature, Vol. 453, pp. 379-382. doi:10.1038/nature06949.

Woods Hole Oceanographic Institution. (2015). Introduction to ocean acidification. Accessed October 4, 2017.

Lindsey, R. (2009). Climate and Earth's energy budget. Accessed October 4, 2017.

Based on the annual report from NOAA's Global Monitoring Lab, global average atmospheric carbon dioxide was 417.06 parts per million ("ppm" for short) in 2022, setting a new record high. The increase between 2021 and 2022 was 2.13 ppm-the 11 th year in a row where the amount of carbon dioxide in the atmosphere increased by more than 2 ppm. At Mauna Loa Observatory in Hawaii, where the modern carbon dioxide record began in 1958, the annual average carbon dioxide in 2022 was 418.56.

Carbon dioxide concentrations are rising mostly because of the fossil fuels that people are burning for energy. Fossil fuels like coal and oil contain carbon that plants pulled out of the atmosphere through photosynthesis over many millions of years; we are returning that carbon to the atmosphere in just a few hundred. Since the middle of the 20 th century, annual emissions from burning fossil fuels have increased every decade, from close to 11 billion tons of carbon dioxide per year in the 1960s to an estimated 36.6 billion tons in 2022 according to the Global Carbon Budget 2022.

Carbon cycle experts estimate that natural "sinks"-processes that remove carbon from the atmosphere-on land and in the ocean absorbed the equivalent of about half of the carbon dioxide we emitted each year in the 2011-2020 decade. Because we put more carbon dioxide into the atmosphere than natural sinks can remove, the total amount of carbon dioxide in the atmosphere increases every year.

The more we overshoot what natural processes can remove in a given year, the faster the atmospheric concentration of carbon dioxide rises. In the 1960s, the global growth rate of atmospheric carbon dioxide was roughly 0.8± 0.1 ppm per year. Over the next half century, the annual growth rate tripled, reaching 2.4 ppm per year during the 2010s. The annual rate of increase in atmospheric carbon dioxide over the past 60 years is about 100 times faster than previous natural increases, such as those that occurred at the end of the last ice age 11,000-17,000 years ago.

Why carbon dioxide matters

Carbon dioxide is Earth's most important greenhouse gas: a gas that absorbs and radiates heat. Unlike oxygen or nitrogen (which make up most of our atmosphere), greenhouse gases absorb heat radiating from the Earth's surface and re-release it in all directions-including back toward Earth's surface. Without carbon dioxide, Earth's natural greenhouse effect would be too weak to keep the average global surface temperature above freezing. By adding more carbon dioxide to the atmosphere, people are supercharging the natural greenhouse effect, causing global temperature to rise. According to observations by the NOAA Global Monitoring Lab, in 2021 carbon dioxide alone was responsible for about two-thirds of the total heating influence of all human-produced greenhouse gases.

Another reason carbon dioxide is important in the Earth system is that it dissolves into the ocean like the fizz in a can of soda. It reacts with water molecules, producing carbonic acid and lowering the ocean's pH (raising its acidity). Since the start of the Industrial Revolution, the pH of the ocean's surface waters has dropped from 8.21 to 8.10. This drop in pH is called ocean acidification.

Past and future carbon dioxide

Natural increases in carbon dioxide concentrations have periodically warmed Earth's temperature during ice age cycles over the past million years or more. The warm episodes (interglacials) began with a small increase in incoming sunlight in the Northern Hemisphere due to variations in Earth's orbit around the Sun and its axis of rotation. (For more details, see the "Milankovitch cycles and ice ages" section of our Climate change: incoming sunlight article.) That little bit of extra sunlight caused a little bit of warming. As the oceans warmed, they outgassed carbon dioxide-like a can of soda going flat in the heat of a summer day. The extra carbon dioxide in the atmosphere greatly amplified the initial, solar-driven warming.

Based on air bubbles trapped in mile-thick ice cores and other paleoclimate evidence, we know that during the ice age cycles of the past million years or so, atmospheric carbon dioxide never exceeded 300 ppm. Before the Industrial Revolution started in the mid-1700s, atmospheric carbon dioxide was 280 ppm or less.

By the time continuous observations began at Mauna Loa Volcanic Observatory in 1958, global atmospheric carbon dioxide was already 315 ppm. Carbon dioxide levels today are higher than at any point in human history. In fact, the last time atmospheric carbon dioxide amounts were this high was more than 3 million years ago, during the Mid-Pliocene Warm Period, when global surface temperature was 4.5-7.2 degrees Fahrenheit (2.5-4 degrees Celsius) warmer than during the pre-industrial era. Sea level was at least 16 feet higher than it was in 1900 and possibly as much as 82 feet higher.

If global energy demand continues to grow rapidly and we meet it mostly with fossil fuels, human emissions of carbon dioxide could reach 75 billion tons per year or more by the end of the century. Atmospheric carbon dioxide could be 800 ppm or higher-conditions not seen on Earth for close to 50 million years.

More on carbon dioxide
NOAA carbon dioxide observations Carbon cycle factsheet Carbon dioxide emissions by country over time Comparing greenhouse gases by their global warming potential Ocean acidification
References

Collins, M., R. Knutti, J. Arblaster, J.-L. Dufresne, T. Fichefet, P. Friedlingstein, X. Gao, W.J. Gutowski, T. Johns, G. Krinner, M. Shongwe, C. Tebaldi, A.J. Weaver and M. Wehner, 2013: Long-term Climate Change: Projections, Commitments and Irreversibility. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Friedlingstein, P., O'Sullivan, M., Jones, M. W., Andrew, R. M., Gregor, L., Hauck, J., Le Quéré, C., Luijkx, I. T., Olsen, A., Peters, G. P., Peters, W., Pongratz, J., Schwingshackl, C., Sitch, S., Canadell, J. G., Ciais, P., Jackson, R. B., Alin, S. R., Alkama, R., ... Zheng, B. (2022). Global Carbon Budget 2022. Earth System Science Data, 14(11), 4811-4900. https://doi.org/10.5194/essd-14-4811-2022

Lan, X., B. D. Hall, G. Dutton, J. Mühle, J. W. Elkins, and I. J. Vimont. (2022). Long-lived greenhouses gases [in State of the Climate in 2021, Chapter 2: Global Climate]. Bulletin of the American Meteorological Society, 103 (8), S81-S84. https://doi.org/10.1175/BAMS-D-22-0092.1.

Lüthi, D., M. Le Floch, B. Bereiter, T. Blunier, J.-M. Barnola, U. Siegenthaler, D. Raynaud, J. Jouzel, H. Fischer, K. Kawamura, and T.F. Stocker. (2008). High-resolution carbon dioxide concentration record 650,000-800,000 years before present. Nature, Vol. 453, pp. 379-382. doi:10.1038/nature06949.

Woods Hole Oceanographic Institution. (2015). Introduction to ocean acidification. Accessed October 4, 2017.

Lindsey, R. (2009). Climate and Earth's energy budget. Accessed October 4, 2017.

# data[].attributes.attachment_link.title
Climate Change: Atmospheric Carbon Dioxide

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In the past 60 years, carbon dioxide in the atmosphere has increased 100 times faster than it did during the end of the last ice age.

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https://www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide

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Based on the annual report from NOAA's Global Monitoring Lab, global average atmospheric carbon dioxide was 417.06 parts per million ("ppm" for short) in 2022, setting a new record high. The increase between 2021 and 2022 was 2.13 ppm-the 11 th year in a row where the amount of carbon dioxide in the atmosphere increased by more than 2 ppm. At Mauna Loa Observatory in Hawaii, where the modern carbon dioxide record began in 1958, the annual average carbon dioxide in 2022 was 418.56.

Carbon dioxide concentrations are rising mostly because of the fossil fuels that people are burning for energy. Fossil fuels like coal and oil contain carbon that plants pulled out of the atmosphere through photosynthesis over many millions of years; we are returning that carbon to the atmosphere in just a few hundred. Since the middle of the 20 th century, annual emissions from burning fossil fuels have increased every decade, from close to 11 billion tons of carbon dioxide per year in the 1960s to an estimated 36.6 billion tons in 2022 according to the Global Carbon Budget 2022.

Carbon cycle experts estimate that natural "sinks"-processes that remove carbon from the atmosphere-on land and in the ocean absorbed the equivalent of about half of the carbon dioxide we emitted each year in the 2011-2020 decade. Because we put more carbon dioxide into the atmosphere than natural sinks can remove, the total amount of carbon dioxide in the atmosphere increases every year.

The more we overshoot what natural processes can remove in a given year, the faster the atmospheric concentration of carbon dioxide rises. In the 1960s, the global growth rate of atmospheric carbon dioxide was roughly 0.8± 0.1 ppm per year. Over the next half century, the annual growth rate tripled, reaching 2.4 ppm per year during the 2010s. The annual rate of increase in atmospheric carbon dioxide over the past 60 years is about 100 times faster than previous natural increases, such as those that occurred at the end of the last ice age 11,000-17,000 years ago.

Why carbon dioxide matters

Carbon dioxide is Earth's most important greenhouse gas: a gas that absorbs and radiates heat. Unlike oxygen or nitrogen (which make up most of our atmosphere), greenhouse gases absorb heat radiating from the Earth's surface and re-release it in all directions-including back toward Earth's surface. Without carbon dioxide, Earth's natural greenhouse effect would be too weak to keep the average global surface temperature above freezing. By adding more carbon dioxide to the atmosphere, people are supercharging the natural greenhouse effect, causing global temperature to rise. According to observations by the NOAA Global Monitoring Lab, in 2021 carbon dioxide alone was responsible for about two-thirds of the total heating influence of all human-produced greenhouse gases.

Another reason carbon dioxide is important in the Earth system is that it dissolves into the ocean like the fizz in a can of soda. It reacts with water molecules, producing carbonic acid and lowering the ocean's pH (raising its acidity). Since the start of the Industrial Revolution, the pH of the ocean's surface waters has dropped from 8.21 to 8.10. This drop in pH is called ocean acidification.

Past and future carbon dioxide

Natural increases in carbon dioxide concentrations have periodically warmed Earth's temperature during ice age cycles over the past million years or more. The warm episodes (interglacials) began with a small increase in incoming sunlight in the Northern Hemisphere due to variations in Earth's orbit around the Sun and its axis of rotation. (For more details, see the "Milankovitch cycles and ice ages" section of our Climate change: incoming sunlight article.) That little bit of extra sunlight caused a little bit of warming. As the oceans warmed, they outgassed carbon dioxide-like a can of soda going flat in the heat of a summer day. The extra carbon dioxide in the atmosphere greatly amplified the initial, solar-driven warming.

Based on air bubbles trapped in mile-thick ice cores and other paleoclimate evidence, we know that during the ice age cycles of the past million years or so, atmospheric carbon dioxide never exceeded 300 ppm. Before the Industrial Revolution started in the mid-1700s, atmospheric carbon dioxide was 280 ppm or less.

By the time continuous observations began at Mauna Loa Volcanic Observatory in 1958, global atmospheric carbon dioxide was already 315 ppm. Carbon dioxide levels today are higher than at any point in human history. In fact, the last time atmospheric carbon dioxide amounts were this high was more than 3 million years ago, during the Mid-Pliocene Warm Period, when global surface temperature was 4.5-7.2 degrees Fahrenheit (2.5-4 degrees Celsius) warmer than during the pre-industrial era. Sea level was at least 16 feet higher than it was in 1900 and possibly as much as 82 feet higher.

If global energy demand continues to grow rapidly and we meet it mostly with fossil fuels, human emissions of carbon dioxide could reach 75 billion tons per year or more by the end of the century. Atmospheric carbon dioxide could be 800 ppm or higher-conditions not seen on Earth for close to 50 million years.

More on carbon dioxide
NOAA carbon dioxide observations Carbon cycle factsheet Carbon dioxide emissions by country over time Comparing greenhouse gases by their global warming potential Ocean acidification
References

Collins, M., R. Knutti, J. Arblaster, J.-L. Dufresne, T. Fichefet, P. Friedlingstein, X. Gao, W.J. Gutowski, T. Johns, G. Krinner, M. Shongwe, C. Tebaldi, A.J. Weaver and M. Wehner, 2013: Long-term Climate Change: Projections, Commitments and Irreversibility. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Friedlingstein, P., O'Sullivan, M., Jones, M. W., Andrew, R. M., Gregor, L., Hauck, J., Le Quéré, C., Luijkx, I. T., Olsen, A., Peters, G. P., Peters, W., Pongratz, J., Schwingshackl, C., Sitch, S., Canadell, J. G., Ciais, P., Jackson, R. B., Alin, S. R., Alkama, R., ... Zheng, B. (2022). Global Carbon Budget 2022. Earth System Science Data, 14(11), 4811-4900. https://doi.org/10.5194/essd-14-4811-2022

Lan, X., B. D. Hall, G. Dutton, J. Mühle, J. W. Elkins, and I. J. Vimont. (2022). Long-lived greenhouses gases [in State of the Climate in 2021, Chapter 2: Global Climate]. Bulletin of the American Meteorological Society, 103 (8), S81-S84. https://doi.org/10.1175/BAMS-D-22-0092.1.

Lüthi, D., M. Le Floch, B. Bereiter, T. Blunier, J.-M. Barnola, U. Siegenthaler, D. Raynaud, J. Jouzel, H. Fischer, K. Kawamura, and T.F. Stocker. (2008). High-resolution carbon dioxide concentration record 650,000-800,000 years before present. Nature, Vol. 453, pp. 379-382. doi:10.1038/nature06949.

Woods Hole Oceanographic Institution. (2015). Introduction to ocean acidification. Accessed October 4, 2017.

Lindsey, R. (2009). Climate and Earth's energy budget. Accessed October 4, 2017.

Based on the annual report from NOAA's Global Monitoring Lab, global average atmospheric carbon dioxide was 417.06 parts per million ("ppm" for short) in 2022, setting a new record high. The increase between 2021 and 2022 was 2.13 ppm-the 11 th year in a row where the amount of carbon dioxide in the atmosphere increased by more than 2 ppm. At Mauna Loa Observatory in Hawaii, where the modern carbon dioxide record began in 1958, the annual average carbon dioxide in 2022 was 418.56.

Carbon dioxide concentrations are rising mostly because of the fossil fuels that people are burning for energy. Fossil fuels like coal and oil contain carbon that plants pulled out of the atmosphere through photosynthesis over many millions of years; we are returning that carbon to the atmosphere in just a few hundred. Since the middle of the 20 th century, annual emissions from burning fossil fuels have increased every decade, from close to 11 billion tons of carbon dioxide per year in the 1960s to an estimated 36.6 billion tons in 2022 according to the Global Carbon Budget 2022.

Carbon cycle experts estimate that natural "sinks"-processes that remove carbon from the atmosphere-on land and in the ocean absorbed the equivalent of about half of the carbon dioxide we emitted each year in the 2011-2020 decade. Because we put more carbon dioxide into the atmosphere than natural sinks can remove, the total amount of carbon dioxide in the atmosphere increases every year.

The more we overshoot what natural processes can remove in a given year, the faster the atmospheric concentration of carbon dioxide rises. In the 1960s, the global growth rate of atmospheric carbon dioxide was roughly 0.8± 0.1 ppm per year. Over the next half century, the annual growth rate tripled, reaching 2.4 ppm per year during the 2010s. The annual rate of increase in atmospheric carbon dioxide over the past 60 years is about 100 times faster than previous natural increases, such as those that occurred at the end of the last ice age 11,000-17,000 years ago.

Why carbon dioxide matters

Carbon dioxide is Earth's most important greenhouse gas: a gas that absorbs and radiates heat. Unlike oxygen or nitrogen (which make up most of our atmosphere), greenhouse gases absorb heat radiating from the Earth's surface and re-release it in all directions-including back toward Earth's surface. Without carbon dioxide, Earth's natural greenhouse effect would be too weak to keep the average global surface temperature above freezing. By adding more carbon dioxide to the atmosphere, people are supercharging the natural greenhouse effect, causing global temperature to rise. According to observations by the NOAA Global Monitoring Lab, in 2021 carbon dioxide alone was responsible for about two-thirds of the total heating influence of all human-produced greenhouse gases.

Another reason carbon dioxide is important in the Earth system is that it dissolves into the ocean like the fizz in a can of soda. It reacts with water molecules, producing carbonic acid and lowering the ocean's pH (raising its acidity). Since the start of the Industrial Revolution, the pH of the ocean's surface waters has dropped from 8.21 to 8.10. This drop in pH is called ocean acidification.

Past and future carbon dioxide

Natural increases in carbon dioxide concentrations have periodically warmed Earth's temperature during ice age cycles over the past million years or more. The warm episodes (interglacials) began with a small increase in incoming sunlight in the Northern Hemisphere due to variations in Earth's orbit around the Sun and its axis of rotation. (For more details, see the "Milankovitch cycles and ice ages" section of our Climate change: incoming sunlight article.) That little bit of extra sunlight caused a little bit of warming. As the oceans warmed, they outgassed carbon dioxide-like a can of soda going flat in the heat of a summer day. The extra carbon dioxide in the atmosphere greatly amplified the initial, solar-driven warming.

Based on air bubbles trapped in mile-thick ice cores and other paleoclimate evidence, we know that during the ice age cycles of the past million years or so, atmospheric carbon dioxide never exceeded 300 ppm. Before the Industrial Revolution started in the mid-1700s, atmospheric carbon dioxide was 280 ppm or less.

By the time continuous observations began at Mauna Loa Volcanic Observatory in 1958, global atmospheric carbon dioxide was already 315 ppm. Carbon dioxide levels today are higher than at any point in human history. In fact, the last time atmospheric carbon dioxide amounts were this high was more than 3 million years ago, during the Mid-Pliocene Warm Period, when global surface temperature was 4.5-7.2 degrees Fahrenheit (2.5-4 degrees Celsius) warmer than during the pre-industrial era. Sea level was at least 16 feet higher than it was in 1900 and possibly as much as 82 feet higher.

If global energy demand continues to grow rapidly and we meet it mostly with fossil fuels, human emissions of carbon dioxide could reach 75 billion tons per year or more by the end of the century. Atmospheric carbon dioxide could be 800 ppm or higher-conditions not seen on Earth for close to 50 million years.

More on carbon dioxide
NOAA carbon dioxide observations Carbon cycle factsheet Carbon dioxide emissions by country over time Comparing greenhouse gases by their global warming potential Ocean acidification
References

Collins, M., R. Knutti, J. Arblaster, J.-L. Dufresne, T. Fichefet, P. Friedlingstein, X. Gao, W.J. Gutowski, T. Johns, G. Krinner, M. Shongwe, C. Tebaldi, A.J. Weaver and M. Wehner, 2013: Long-term Climate Change: Projections, Commitments and Irreversibility. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Friedlingstein, P., O'Sullivan, M., Jones, M. W., Andrew, R. M., Gregor, L., Hauck, J., Le Quéré, C., Luijkx, I. T., Olsen, A., Peters, G. P., Peters, W., Pongratz, J., Schwingshackl, C., Sitch, S., Canadell, J. G., Ciais, P., Jackson, R. B., Alin, S. R., Alkama, R., ... Zheng, B. (2022). Global Carbon Budget 2022. Earth System Science Data, 14(11), 4811-4900. https://doi.org/10.5194/essd-14-4811-2022

Lan, X., B. D. Hall, G. Dutton, J. Mühle, J. W. Elkins, and I. J. Vimont. (2022). Long-lived greenhouses gases [in State of the Climate in 2021, Chapter 2: Global Climate]. Bulletin of the American Meteorological Society, 103 (8), S81-S84. https://doi.org/10.1175/BAMS-D-22-0092.1.

Lüthi, D., M. Le Floch, B. Bereiter, T. Blunier, J.-M. Barnola, U. Siegenthaler, D. Raynaud, J. Jouzel, H. Fischer, K. Kawamura, and T.F. Stocker. (2008). High-resolution carbon dioxide concentration record 650,000-800,000 years before present. Nature, Vol. 453, pp. 379-382. doi:10.1038/nature06949.

Woods Hole Oceanographic Institution. (2015). Introduction to ocean acidification. Accessed October 4, 2017.

Lindsey, R. (2009). Climate and Earth's energy budget. Accessed October 4, 2017.

# data[].attributes.attachment_link.title
Climate Change: Atmospheric Carbon Dioxide

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In the past 60 years, carbon dioxide in the atmosphere has increased 100 times faster than it did during the end of the last ice age.

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https://www.livescience.com/secret-polar-bear-population
위 글에서는 북극의 해빙 면적이 증가하고 있고 세기말에는 북극곰이 사라질수 있다고 한다.

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(Image credit: Kristin Laidre/University of Washington)

(opens in new tab)

A secret population of polar bears in Greenland has been discovered in a seemingly impossible habitat - one that, for most of the year, lacks the floating platforms of sea ice the beasts use to hunt. The unusual group, which scientists previously thought was part of another nearby population, has been hiding in plain sight for hundreds of years.

The bears live on the steep slopes around fjords - long and narrow coastal inlets, where glaciers meet the ocean - and hunt on a patchwork of glacial ice that breaks up in these inlets. The new discovery suggests that some polar bears, at least, may be able to adapt to sea ice disappearing as climate change worsens, the study suggests.

Still, that's no silver bullet for the species at large.

"Glacier ice may help small numbers of polar bears survive for longer periods under climate warming, but it is not available for the vast majority of polar bears," lead researcher Kristin Laidre, a wildlife scientist at Polar Science Center at the University of Washington, told Live Science in an email. That's because this type of glacier ice is only found near a small fraction of other polar bear populations.
Related: Why aren't there polar bears in Antarctica?
Until recently, scientists had identified 19 known subpopulations of polar bears ( Ursus maritimus) living in the Arctic Circle. One of those populations spans a 1,988-mile (3,200 kilometers) stretch of the eastern coast of Greenland. But when researchers took a detailed look at this group to monitor their numbers, they realized the bears actually comprised two completely separate populations.

Researchers analyzed 36 years' worth of tracking data from bears tagged with GPS collars and found that bears from southeast Greenland did not pass above a latitude of 64 degrees north, and bears from the northeast did not pass the same line in the other direction. Genetic sampling from individual bears confirmed that the southeastern bears were distinct from their northeastern neighbors.

"We present the first evidence for a genetically distinct and functionally isolated group of polar bears in southeast Greenland, which meet [the] criteria for recognition as the world's 20th polar bear subpopulation," the researchers wrote in their new study, which was published June 16 in the journal (opens in new tab).

The new southeastern population contains around 300 individuals, although determining an exact number is tricky, the researchers said. The newfound group is the most genetically diverse out of all 20 populations in the Arctic, and genetic comparisons suggest that they have been isolated from the northeastern population for around 200 years, the researchers said.

Polar bears are listed as vulnerable to extinction, according to the International Union for Conservation of Nature (IUCN) Red List (opens in new tab), and there are around 36,000 individuals left in the wild. But some studies have suggested that the species could vanish by the end of the century due to the effects of climate change.

Despite being the world's largest land predator, polar bears are actually listed as marine mammals because they rely on a predominantly aquatic diet, consisting mainly of seals. But in order to hunt for food, the snow-white bears rely on sea ice as a platform to stalk their prey from above. Unfortunately, rising temperatures caused by climate change are reducing the amount of sea ice available, shrinking their natural habitat.

Sea-ice extent waxes and wanes in the Arctic. The temporary ice sheets form on the ocean's surface during autumn and then melt away in spring. Polar bears normally survive for between 100 and 180 days without food as the sea ice disappears over the summer. But warming temperatures in the Arctic mean that sea ice is melting sooner and freezing later, pushing polar bears to the brink of starvation.

(Image credit: Kristin Laidre/University of Washington)

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The fjords that are home to the southeastern polar bears lie at the southern edge of the Arctic Circle and, as a result, the region is sea ice-free for more than 250 days a year. These sea ice conditions mimic those predicted for the rest of the Arctic by the end of the 21st century, based on previous studies, which should make the fjords unlivable for polar bears, the researchers said. But the southeastern bears seem to be managing surprisingly well without the sea ice.

The researchers think that the bears are taking advantage of glacial mélange, or the bits of ice that break off the fjords' glaciers and into the sea. The bears likely use these freshwater ice patches in the same way they use sea ice to hunt, which allows them to feed themselves during the long spells when sea ice is absent from the region. "This suggests that marine-terminating glaciers may serve as previously unrecognized climate refugia," the researchers wrote.

The southeastern population also lives nowhere near any human populations, and the area is believed to be too hard to reach for most hunters, which adds an extra layer of security for the bears. However, the steep slopes of the fjords can also be quite tricky for the polar bears to traverse, which may limit their movements. The birth rate among the new population is also very low compared with other populations, which researchers suspect is because potential mates struggle to reach one another.

In the new study, the researchers used genetic data to identify two individuals that could be immigrants from the northeastern population. These immigrant bears appear to have adapted very well to hunting on glacial mélange, which suggests that other populations might be able to follow suit as sea ice conditions deteriorate in other areas. The researchers identified other similar locations where glacial conditions could support polar bears in northern Greenland and Svalbard. However, moving to these locations may not be possible for a majority of bears.
Originally published on Live Science.
Although the study does provide a glimmer of hope for some polar bears, the researchers insist that this does not make climate change any less of a threat to the Arctic predators. "Loss of Arctic sea ice is still the primary threat to all polar bears," Laidre said. "This study does not change that." Sea ice will continue to decline across the Arctic, which will decrease the survival odds for most polar bears, she added.

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Secret population of polar bears found living in seemingly impossible habitat

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(opens in new tab) A secret population of polar bears in Greenland has been discovered in a seemingly impossible habitat - one that, for most of the year, lacks the floating platforms of sea ice the beasts use to hunt.

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Sea level has risen 8-9 inches since 1880, and the rate is accelerating thanks to glacier and ice sheet melt.

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https://padlet.com/yim26581/3q80ro43fie1srg9/wish/2312877359

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See all climate myths in our special feature.
Polar bears have become the poster children of global warming. The bears spend most or all of the year living and hunting on sea ice, and the accelerating shrinking of this ice appears to pose a serious threat. The issue has even become politically sensitive.

Yet recently there have been claims that polar bear populations are increasing. So what's going on? There are thought to be between 20,000 and 25,000 polar bears in 19 population groups around the Arctic. While polar bear numbers are increasing in two of these populations, two others are definitely in decline. We don't really know how the rest of the populations are faring, so the truth is that no one can say for sure how overall numbers are changing.

The two populations that are increasing, both in north-eastern Canada, were severely reduced by hunting in the past and are recovering thanks to the protection they and their prey now enjoy.

The best-studied population, in Canada's western Hudson Bay, fell by 22% from 1194 animals in 1987 to 935 in 2004, according to the US Fish and Wildlife Service. A second group in the Beaufort Sea, off Alaska's north coast, is now experiencing the same pattern of reduced adult weights and cub survival as the Hudson Bay group.

A comprehensive review (pdf) by the US Fish and Wildlife Service concluded that shrinking sea ice is the primary cause for the decline seen in these populations, and it recently proposed listing polar bears as threatened (pdf) under the Endangered Species Act. The World Conservation Union projects the bears' numbers will drop by 30% by 2050 (pdf) due to continued loss of Arctic sea ice.

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Climate myths: Polar bear numbers are increasing

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See all climate myths in our special feature. Polar bears have become the poster children of global warming. The bears spend most or all of the year living and hunting on sea ice, and the accelerating shrinking of this ice appears to pose a serious threat. The issue has even become politically sensitive.

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https://scholar.google.com/scholar?hl=ko&as_sdt=0,5&qsp=1&q=polar+bear+population+decline&qst=ib#d=gs_qabs&t=1664324519022&u=%23p%3D8TFlFBYkhdAJ

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https://www.science.org/doi/abs/10.1126/science.1106663

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https://climate.nasa.gov/effects/

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Climate Change: Vital Signs of the Planet

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Our Trajectory

Earth Will Continue to Warm and the Effects Will Be Profound

The potential future effects of global climate change include more frequent wildfires, longer periods of drought in some regions, and an increase in the wind intensity and rainfall from tropical cyclones. Credit: left - Mike McMillan/USFS, center - Tomas Castelazo / Wikimedia Commons / CC BY-SA 4.0, right - NASA.

Global climate change is not a future problem. Changes to Earth's climate driven by increased human emissions of heat-trapping greenhouse gases are already having widespread effects on the environment: glaciers and ice sheets are shrinking, river and lake ice is breaking up earlier, plant and animal geographic ranges are shifting, and plants and trees are blooming sooner.

Effects that scientists had long predicted would result from global climate change are now occurring, such as sea ice loss, accelerated sea level rise, and longer, more intense heat waves.

" The magnitude and rate of climate change and associated risks depend strongly on near-term mitigation and adaptation actions, and projected adverse impacts and related losses and damages escalate with every increment of global warming."

- Intergovernmental Panel on Climate Change

Some changes (such as droughts, wildfires, and extreme rainfall) are happening faster than scientists previously assessed. In fact, according to the Intergovernmental Panel on Climate Change (IPCC) - the United Nations body established to assess the science related to climate change - modern humans have never before seen the observed changes in our global climate, and some of these changes are irreversible over the next hundreds to thousands of years.

Scientists have high confidence that global temperatures will continue to rise for many decades, mainly due to greenhouse gases produced by human activities.

A Degree of Difference

So, the Earth's average temperature has increased about 2 degrees Fahrenheit during the 20th century. What's the big deal?

Read more

The IPCC's Sixth Assessment report, published in 2021, found that human emissions of heat-trapping gases have already warmed the climate by nearly 2 degrees Fahrenheit (1.1 degrees Celsius) since 1850-1900. The global average temperature is expected to reach or exceed 1.5 degrees C (about 3 degrees F) within the next few decades. These changes will affect all regions of Earth.

What's the difference between climate change and global warming?

"Global warming" refers to the long-term warming of the planet. "Climate change" encompasses global warming, but refers to the broader range of changes that are happening to our planet, including rising sea levels; shrinking mountain glaciers; accelerating ice melt in Greenland, Antarctica and the Arctic; and shifts in flower/plant blooming times.

detailed answer

The severity of effects caused by climate change will depend on the path of future human activities. More greenhouse gas emissions will lead to more climate extremes and widespread damaging effects across our planet. However, those future effects depend on the total amount of carbon dioxide we emit. So, if we can reduce emissions, we may avoid some of the worst effects.

" The scientific evidence is unequivocal: climate change is a threat to human wellbeing and the health of the planet. Any further delay in concerted global action will miss the brief, rapidly closing window to secure a liveable future." ²

- Intergovernmental Panel on Climate Change

Future Effects in the U.S.

U.S. Regional Effects

U.S. Regional Effects

Climate change is bringing different types of challenges to each region of the country. Some of the current and future impacts are summarized below. These findings are from the Third and Fourth National Climate Assessment Reports, released by the U.S. Global Change Research Program.

Is it too late to prevent climate change?

Humans have caused major climate changes to happen already, and we have set in motion more changes still. However, if we stopped emitting greenhouse gases today, the rise in global temperatures would begin to flatten within a few years. Temperatures would then plateau but remain well-elevated for many, many centuries.

detailed answer

Northeast. Heat waves, heavy downpours, and sea level rise pose increasing challenges to many aspects of life in the Northeast. Infrastructure, agriculture, fisheries, and ecosystems will be increasingly compromised. Farmers can explore new crop options, but these adaptations are not cost- or risk-free. Moreover, adaptive capacity, which varies throughout the region, could be overwhelmed by a changing climate. Many states and cities are beginning to incorporate climate change into their planning.

Northwest. Changes in the timing of peak flows in rivers and streams are reducing water supplies and worsening competing demands for water. Sea level rise, erosion, flooding, risks to infrastructure, and increasing ocean acidity pose major threats. Increasing wildfire incidence and severity, heat waves, insect outbreaks, and tree diseases are causing widespread forest die-off.

Southeast. Sea level rise poses widespread and continuing threats to the region's economy and environment. Extreme heat will affect health, energy, agriculture, and more. Decreased water availability will have economic and environmental impacts.

Midwest. Extreme heat, heavy downpours, and flooding will affect infrastructure, health, agriculture, forestry, transportation, air and water quality, and more. Climate change will also worsen a range of risks to the Great Lakes.

Southwest. Climate change has caused increased heat, drought, and insect outbreaks. In turn, these changes have made wildfires more numerous and severe. The warming climate has also caused a decline in water supplies, reduced agricultural yields, and triggered heat-related health impacts in cities. In coastal areas, flooding and erosion are additional concerns.

References
References
Header image shows cracked mud stretches across sections of the Panamint Valley. Credit: NPS/Kurt Moses; A degree of concern thermometer image credit: Pixabay/geralt

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intergovernmental panel on climate change

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Vital Signs of the Planet: Global Climate Change and Global Warming. Long-term effects of global climate change in the United States.

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https://www.sciencetimes.co.kr/news/%EC%9D%B4%EC%82%B0%ED%99%94%ED%83%84%EC%86%8C%EA%B0%80-%EC%A7%80%EA%B5%AC%EC%98%A8%EB%82%9C%ED%99%94-%EB%8A%A6%EC%B6%98%EB%8B%A4/

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자료 1
자료 2: https://unctad.org/news/green-industrial-policies-key-developing-countries-adapt-climate-change

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https://imnews.imbc.com/news/2022/society/article/6404610_35673.html
최근 발생한 자연재해가 위력이 크다는 자료.

https://www.ibs.re.kr/cop/bbs/BBSMSTR_000000000735/selectBoardArticle.do?nttId=19484
최근 발생한 위력이 강한 자연재해가 기후변화 때문이라는 자료

https://m.dongascience.com/news.php?idx=40588
위 글에는 최근 20년간 자연재해 발생 횟수가 약 2배 증가했다고 나와있다.

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힌남노 위력, 역대 태풍과 비교하면?

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이번 태풍 힌남노는 과거 한반도에 영향을 준 어떤 태풍보다도 강력할 것으로 전망되는데요. 그동안 우리나라를 거쳐간 태풍들과 비교했을 때 얼마나 세고, 어떻게 다른지, ...

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anomaly
deviation of a meteorological quantity value in a given region from the normal ( mean) value for the same period.
Topic: ...

anomaly 1: unusual temperature or precipitation for a given region over a specified period. Also see anomaly 2 ( Orbital Mechanics section).
anticyclone: high pressure area with counterclockwise winds in the Southern Hemisphere and clockwise winds in the Norther n Hemisphere.

Anomaly
The departure of an element from its long-period average value for the location concerned. For example, if the maximum temperature for June in Melbourne was 1 degree Celsius higher than the long-term average for this month, the anomaly would be +1 degrees Celsius.

~ - The deviation of a measurable unit, (e.g., temperature or precipitation) in a given region over a specified period from the long-term average, often the thirty year mean, for the same region.
AO - See Arctic Oscillation ...

~
The deviation of a measurable unit (e.g., temperature or precipitation) over a period in a given region from the long-term average, often the thirty-year mean, for that region.

~: The difference of temperature or precipitation from the average or normal.
Atmosphere: The mass of air surrounding the Earth and bound to it more or less permanently by the Earth's gravitation al attraction.

~
the departure or deviation from normal. For example, let's say that the normal temperature for a month is 50 °F. If the actual temperature average for the month is 55 °F, the monthly temperature is 5 °F above normal, which is a positive ~ of 5 °F.

~
The difference between the mean of any meteorological element, and the phase of that element over the same time for all other points on the same parallel of latitude.
Anticyclone ...

3 ~ (climatic) - A climatic fluctuation whose amplitude ( intensity and spatial extent) is outside the standard of the fluctuations observed, that is to say fairly remote from the climatic mean.

~
Value that represents the difference between the value for a given year or season from the normal of the reference period.
ANUSPLIN ...

An ~ arose in the late 19th century involving a contradiction between the wave theory of light and measurements of the electromagnetic spectra that were being emitted by thermal radiator s known as black bodies. Physicists struggled with this problem unsuccessfully for many years.

Define ~ in your own words. What does it mean to be different than average?
What is the trend in average global temperatures?
Indicator s of change in the United States ...

Temperature ~: The deviation of temperature in a given region over a specified period from the long-term average value for the same region.
Thermosphere: Layer of the Earth's atmosphere, above the mesopause, in which the temperature generally increases with height.

Tide ~Actual water level minus the prediction. Tide PredictionThe computation of tidal highs and lows at a given location resulting from the gravitational interactions between the earth and primarily the moon and sun.

SST ~ = (SST - SST mean). secular carbon dioxide trend The fairly uniform and accelerating increase of carbon dioxide concentration in the atmosphere, as illustrated by the Mauna Loa record.

Atlantic convergence zone SH Southern Hemisphere SI units International System of Units SLP sea level pressure SNR signal-to- noise ratio SOFAR sound fixing and ranging SOI Southern Oscillation index SON September-November SPCZ South Pacific convergence zone SSA sea surface ~ ...

Actually any type of storm or weather ~ can be followed, tracked, and observed in many ways. First of all, I need to cover the types of storm observing that can be done. Storms can be directly penetrated or so called, core punched. This is where the chaser passed through the center of the storm.

(1999) suggested that the variability of Betula tree stomata might explain the ~, but Wagner and colleagues maintained their stance, stating that the early Holocene CO2 trend has also been detected in a record of Betula leaves from Denmark and that in addition to the Preboreal oscillation, cooling events at 7, ...

An El Niño event is identified by warmer than normal sea surface temperatures (SSTs). An SST ~ plot, like the one given below, shows the difference between the observed SSTs and the normal SSTs for a given month. This particular plot depicts the SST ~ from December of 1982.
Image by: Liu ...

Often measured by the surface pressure ~ difference between Tahiti and Darwin or the sea surface temperatures in the central and eastern equatorial Pacific. There are three phases: neutral, El NiÃ±o and La NiÃ±a.

such as the predictability of an event, and the ability of the public and media to receive notice of the message, may in fluence the actual lead times provided.
Temperature
In meteorological terms, temperature refers to the degree of heat or cold of the air, as measured by a thermometer.
Temperature ~ ...

both from the atmosphere and from the solar wind; particles from the solar wind become trapped by the earth's magnetic field and are responsible for the aurora borealis seen at polar regions. A part of a belt dips into the upper region of the atmosphere over the South Atlantic to form the Southern Atlantic ~.

It is highly correlated with tropical sea surface temperature ~ indices recorded in NiÃ±o3.
See also: What is the meaning of High Wind Watch, Sun rays, Recession, Thunderstorm electrification, Aviation weather center?

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Anomaly (Meteorology) - Definition - Lexicon & Encyclopedia

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anomaly deviation of a meteorological quantity value in a given region from the normal ( mean) value for the same period.Topic: ... anomaly 1: unusual temperature or precipitation for a given region over a specified period. Also see anomaly 2 ( Orbital Mechanics section).

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https://climate.nasa.gov/vital-signs/sea-level/

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Climate Change: Vital Signs of the Planet

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101 (± 4.0) mm

This is the "uncertainty margin," or the range from the mean (average) within which there is a high probability that the true number resides. For example, when we say global sea level has risen 101 mm +/- 4 mm, the true value has a high probability of being between 97 and 105 mm. The uncertainty margin exists both because of sea level variability (sea level above the first point in the time series) in the ocean and the accuracy with which we measure the individual values.

Key Takeaway:

Global sea levels are rising as a result of human-caused global warming, with recent rates being unprecedented over the past 2,500-plus years.

Sea level rise is caused primarily by two factors related to global warming: the added water from melting ice sheets and glaciers, and the expansion of seawater as it warms. The first graph tracks the change in global sea level since 1993, as observed by satellites.

The second graph, which is from coastal tide gauge and satellite data, shows how much sea level changed from about 1900 to 2018. Items with pluses (+) are factors that cause global sea level to increase, while minuses (-) are what cause sea level to decrease. These items are displayed at the time they were affecting sea level.

The data shown are the latest available, with a four- to five-month delay needed for processing.

* You now need to create an Earthdata account to access NASA's sea level data. Register here for free. Once logged in, click the "download data" button on this page to access the data.
NASA Sea Level Change

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Vital Signs of the Planet: Global Climate Change and Global Warming. Current news and data streams about global warming and climate change from NASA.

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Burning fossil fuels, cutting down forests and farming livestock are increasingly influencing the climate and the earth's temperature.

This adds enormous amounts of greenhouse gases to those naturally occurring in the atmosphere, increasing the greenhouse effect and global warming.

Global warming

2011-2020 was the warmest decade recorded, with global average temperature reaching 1.1°C above pre-industrial levels in 2019. Human-induced global warming is presently increasing at a rate of 0.2°C per decade.

An increase of 2°C compared to the temperature in pre-industrial times is associated with serious negative impacts on to the natural environment and human health and wellbeing, including a much higher risk that dangerous and possibly catastrophic changes in the global environment will occur.

For this reason, the international community has recognised the need to keep warming well below 2°C and pursue efforts to limit it to 1.5°C.

Greenhouse gases

The main driver of climate change is the greenhouse effect. Some gases in the Earth's atmosphere act a bit like the glass in a greenhouse, trapping the sun's heat and stopping it from leaking back into space and causing global warming.

Many of these greenhouse gases occur naturally, but human activities are increasing the concentrations of some of them in the atmosphere, in particular:

CO ₂ produced by human activities is the largest contributor to global warming. By 2020, its concentration in the atmosphere had risen to 48% above its pre-industrial level (before 1750).

Other greenhouse gases are emitted by human activities in smaller quantities. Methane is a more powerful greenhouse gas than CO ₂, but has a shorter atmospheric lifetime. Nitrous oxide, like CO ₂, is a long-lived greenhouse gas that accumulates in the atmosphere over decades to centuries. Non-greenhouse gas pollutants, including aerosols like soot, have different warming and cooling effects and are also associated with other issues such as poor air quality.

Natural causes, such as changes in solar radiation or volcanic activity are estimated to have contributed less than plus or minus 0.1°C to total warming between 1890 and 2010.

Causes for rising emissions

Burning coal, oil and gas produces carbon dioxide and nitrous oxide.

Cutting down forests (deforestation). Trees help to regulate the climate by absorbing CO₂ from the atmosphere. When they are cut down, that beneficial effect is lost and the carbon stored in the trees is released into the atmosphere, adding to the greenhouse effect.

Increasing livestock farming. Cows and sheep produce large amounts of methane when they digest their food.

Fertilisers containing nitrogen produce nitrous oxide emissions.

Fluorinated gases are emitted from equipment and products that use these gases. Such emissions have a very strong warming effect, up to 23 000 times greater than CO₂.

Countering climate change

As every tonne of CO ₂ emitted contributes to global warming, all emissions reductions contribute to slowing it down. In order to stop global warming completely, CO ₂ emissions have to reach net zero worldwide. In addition, reducing emissions of other greenhouse gases, such as methane, can also have a powerful effect on slowing global warming - especially in the short term.

The consequences of climate change are extremely serious, and affect many aspects of our lives. Both countering climate change and adapting to a warming world are top priorities for the EU.We need climate action now. Find out about what the EU is doing to fight the climate crisis.

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Burning fossil fuels, cutting down forests and farming livestock are increasingly influencing the climate and the earth's temperature.

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https://www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide

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Based on the annual report from NOAA's Global Monitoring Lab, global average atmospheric carbon dioxide was 417.06 parts per million ("ppm" for short) in 2022, setting a new record high. The increase between 2021 and 2022 was 2.13 ppm-the 11 th year in a row where the amount of carbon dioxide in the atmosphere increased by more than 2 ppm. At Mauna Loa Observatory in Hawaii, where the modern carbon dioxide record began in 1958, the annual average carbon dioxide in 2022 was 418.56.

Carbon dioxide concentrations are rising mostly because of the fossil fuels that people are burning for energy. Fossil fuels like coal and oil contain carbon that plants pulled out of the atmosphere through photosynthesis over many millions of years; we are returning that carbon to the atmosphere in just a few hundred. Since the middle of the 20 th century, annual emissions from burning fossil fuels have increased every decade, from close to 11 billion tons of carbon dioxide per year in the 1960s to an estimated 36.6 billion tons in 2022 according to the Global Carbon Budget 2022.

Carbon cycle experts estimate that natural "sinks"-processes that remove carbon from the atmosphere-on land and in the ocean absorbed the equivalent of about half of the carbon dioxide we emitted each year in the 2011-2020 decade. Because we put more carbon dioxide into the atmosphere than natural sinks can remove, the total amount of carbon dioxide in the atmosphere increases every year.

The more we overshoot what natural processes can remove in a given year, the faster the atmospheric concentration of carbon dioxide rises. In the 1960s, the global growth rate of atmospheric carbon dioxide was roughly 0.8± 0.1 ppm per year. Over the next half century, the annual growth rate tripled, reaching 2.4 ppm per year during the 2010s. The annual rate of increase in atmospheric carbon dioxide over the past 60 years is about 100 times faster than previous natural increases, such as those that occurred at the end of the last ice age 11,000-17,000 years ago.

Why carbon dioxide matters

Carbon dioxide is Earth's most important greenhouse gas: a gas that absorbs and radiates heat. Unlike oxygen or nitrogen (which make up most of our atmosphere), greenhouse gases absorb heat radiating from the Earth's surface and re-release it in all directions-including back toward Earth's surface. Without carbon dioxide, Earth's natural greenhouse effect would be too weak to keep the average global surface temperature above freezing. By adding more carbon dioxide to the atmosphere, people are supercharging the natural greenhouse effect, causing global temperature to rise. According to observations by the NOAA Global Monitoring Lab, in 2021 carbon dioxide alone was responsible for about two-thirds of the total heating influence of all human-produced greenhouse gases.

Another reason carbon dioxide is important in the Earth system is that it dissolves into the ocean like the fizz in a can of soda. It reacts with water molecules, producing carbonic acid and lowering the ocean's pH (raising its acidity). Since the start of the Industrial Revolution, the pH of the ocean's surface waters has dropped from 8.21 to 8.10. This drop in pH is called ocean acidification.

Past and future carbon dioxide

Natural increases in carbon dioxide concentrations have periodically warmed Earth's temperature during ice age cycles over the past million years or more. The warm episodes (interglacials) began with a small increase in incoming sunlight in the Northern Hemisphere due to variations in Earth's orbit around the Sun and its axis of rotation. (For more details, see the "Milankovitch cycles and ice ages" section of our Climate change: incoming sunlight article.) That little bit of extra sunlight caused a little bit of warming. As the oceans warmed, they outgassed carbon dioxide-like a can of soda going flat in the heat of a summer day. The extra carbon dioxide in the atmosphere greatly amplified the initial, solar-driven warming.

Based on air bubbles trapped in mile-thick ice cores and other paleoclimate evidence, we know that during the ice age cycles of the past million years or so, atmospheric carbon dioxide never exceeded 300 ppm. Before the Industrial Revolution started in the mid-1700s, atmospheric carbon dioxide was 280 ppm or less.

By the time continuous observations began at Mauna Loa Volcanic Observatory in 1958, global atmospheric carbon dioxide was already 315 ppm. Carbon dioxide levels today are higher than at any point in human history. In fact, the last time atmospheric carbon dioxide amounts were this high was more than 3 million years ago, during the Mid-Pliocene Warm Period, when global surface temperature was 4.5-7.2 degrees Fahrenheit (2.5-4 degrees Celsius) warmer than during the pre-industrial era. Sea level was at least 16 feet higher than it was in 1900 and possibly as much as 82 feet higher.

If global energy demand continues to grow rapidly and we meet it mostly with fossil fuels, human emissions of carbon dioxide could reach 75 billion tons per year or more by the end of the century. Atmospheric carbon dioxide could be 800 ppm or higher-conditions not seen on Earth for close to 50 million years.

More on carbon dioxide
NOAA carbon dioxide observations Carbon cycle factsheet Carbon dioxide emissions by country over time Comparing greenhouse gases by their global warming potential Ocean acidification
References

Collins, M., R. Knutti, J. Arblaster, J.-L. Dufresne, T. Fichefet, P. Friedlingstein, X. Gao, W.J. Gutowski, T. Johns, G. Krinner, M. Shongwe, C. Tebaldi, A.J. Weaver and M. Wehner, 2013: Long-term Climate Change: Projections, Commitments and Irreversibility. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Friedlingstein, P., O'Sullivan, M., Jones, M. W., Andrew, R. M., Gregor, L., Hauck, J., Le Quéré, C., Luijkx, I. T., Olsen, A., Peters, G. P., Peters, W., Pongratz, J., Schwingshackl, C., Sitch, S., Canadell, J. G., Ciais, P., Jackson, R. B., Alin, S. R., Alkama, R., ... Zheng, B. (2022). Global Carbon Budget 2022. Earth System Science Data, 14(11), 4811-4900. https://doi.org/10.5194/essd-14-4811-2022

Lan, X., B. D. Hall, G. Dutton, J. Mühle, J. W. Elkins, and I. J. Vimont. (2022). Long-lived greenhouses gases [in State of the Climate in 2021, Chapter 2: Global Climate]. Bulletin of the American Meteorological Society, 103 (8), S81-S84. https://doi.org/10.1175/BAMS-D-22-0092.1.

Lüthi, D., M. Le Floch, B. Bereiter, T. Blunier, J.-M. Barnola, U. Siegenthaler, D. Raynaud, J. Jouzel, H. Fischer, K. Kawamura, and T.F. Stocker. (2008). High-resolution carbon dioxide concentration record 650,000-800,000 years before present. Nature, Vol. 453, pp. 379-382. doi:10.1038/nature06949.

Woods Hole Oceanographic Institution. (2015). Introduction to ocean acidification. Accessed October 4, 2017.

Lindsey, R. (2009). Climate and Earth's energy budget. Accessed October 4, 2017.

Based on the annual report from NOAA's Global Monitoring Lab, global average atmospheric carbon dioxide was 417.06 parts per million ("ppm" for short) in 2022, setting a new record high. The increase between 2021 and 2022 was 2.13 ppm-the 11 th year in a row where the amount of carbon dioxide in the atmosphere increased by more than 2 ppm. At Mauna Loa Observatory in Hawaii, where the modern carbon dioxide record began in 1958, the annual average carbon dioxide in 2022 was 418.56.

Carbon dioxide concentrations are rising mostly because of the fossil fuels that people are burning for energy. Fossil fuels like coal and oil contain carbon that plants pulled out of the atmosphere through photosynthesis over many millions of years; we are returning that carbon to the atmosphere in just a few hundred. Since the middle of the 20 th century, annual emissions from burning fossil fuels have increased every decade, from close to 11 billion tons of carbon dioxide per year in the 1960s to an estimated 36.6 billion tons in 2022 according to the Global Carbon Budget 2022.

Carbon cycle experts estimate that natural "sinks"-processes that remove carbon from the atmosphere-on land and in the ocean absorbed the equivalent of about half of the carbon dioxide we emitted each year in the 2011-2020 decade. Because we put more carbon dioxide into the atmosphere than natural sinks can remove, the total amount of carbon dioxide in the atmosphere increases every year.

The more we overshoot what natural processes can remove in a given year, the faster the atmospheric concentration of carbon dioxide rises. In the 1960s, the global growth rate of atmospheric carbon dioxide was roughly 0.8± 0.1 ppm per year. Over the next half century, the annual growth rate tripled, reaching 2.4 ppm per year during the 2010s. The annual rate of increase in atmospheric carbon dioxide over the past 60 years is about 100 times faster than previous natural increases, such as those that occurred at the end of the last ice age 11,000-17,000 years ago.

Why carbon dioxide matters

Carbon dioxide is Earth's most important greenhouse gas: a gas that absorbs and radiates heat. Unlike oxygen or nitrogen (which make up most of our atmosphere), greenhouse gases absorb heat radiating from the Earth's surface and re-release it in all directions-including back toward Earth's surface. Without carbon dioxide, Earth's natural greenhouse effect would be too weak to keep the average global surface temperature above freezing. By adding more carbon dioxide to the atmosphere, people are supercharging the natural greenhouse effect, causing global temperature to rise. According to observations by the NOAA Global Monitoring Lab, in 2021 carbon dioxide alone was responsible for about two-thirds of the total heating influence of all human-produced greenhouse gases.

Another reason carbon dioxide is important in the Earth system is that it dissolves into the ocean like the fizz in a can of soda. It reacts with water molecules, producing carbonic acid and lowering the ocean's pH (raising its acidity). Since the start of the Industrial Revolution, the pH of the ocean's surface waters has dropped from 8.21 to 8.10. This drop in pH is called ocean acidification.

Past and future carbon dioxide

Natural increases in carbon dioxide concentrations have periodically warmed Earth's temperature during ice age cycles over the past million years or more. The warm episodes (interglacials) began with a small increase in incoming sunlight in the Northern Hemisphere due to variations in Earth's orbit around the Sun and its axis of rotation. (For more details, see the "Milankovitch cycles and ice ages" section of our Climate change: incoming sunlight article.) That little bit of extra sunlight caused a little bit of warming. As the oceans warmed, they outgassed carbon dioxide-like a can of soda going flat in the heat of a summer day. The extra carbon dioxide in the atmosphere greatly amplified the initial, solar-driven warming.

Based on air bubbles trapped in mile-thick ice cores and other paleoclimate evidence, we know that during the ice age cycles of the past million years or so, atmospheric carbon dioxide never exceeded 300 ppm. Before the Industrial Revolution started in the mid-1700s, atmospheric carbon dioxide was 280 ppm or less.

By the time continuous observations began at Mauna Loa Volcanic Observatory in 1958, global atmospheric carbon dioxide was already 315 ppm. Carbon dioxide levels today are higher than at any point in human history. In fact, the last time atmospheric carbon dioxide amounts were this high was more than 3 million years ago, during the Mid-Pliocene Warm Period, when global surface temperature was 4.5-7.2 degrees Fahrenheit (2.5-4 degrees Celsius) warmer than during the pre-industrial era. Sea level was at least 16 feet higher than it was in 1900 and possibly as much as 82 feet higher.

If global energy demand continues to grow rapidly and we meet it mostly with fossil fuels, human emissions of carbon dioxide could reach 75 billion tons per year or more by the end of the century. Atmospheric carbon dioxide could be 800 ppm or higher-conditions not seen on Earth for close to 50 million years.

More on carbon dioxide
NOAA carbon dioxide observations Carbon cycle factsheet Carbon dioxide emissions by country over time Comparing greenhouse gases by their global warming potential Ocean acidification
References

Collins, M., R. Knutti, J. Arblaster, J.-L. Dufresne, T. Fichefet, P. Friedlingstein, X. Gao, W.J. Gutowski, T. Johns, G. Krinner, M. Shongwe, C. Tebaldi, A.J. Weaver and M. Wehner, 2013: Long-term Climate Change: Projections, Commitments and Irreversibility. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.

Friedlingstein, P., O'Sullivan, M., Jones, M. W., Andrew, R. M., Gregor, L., Hauck, J., Le Quéré, C., Luijkx, I. T., Olsen, A., Peters, G. P., Peters, W., Pongratz, J., Schwingshackl, C., Sitch, S., Canadell, J. G., Ciais, P., Jackson, R. B., Alin, S. R., Alkama, R., ... Zheng, B. (2022). Global Carbon Budget 2022. Earth System Science Data, 14(11), 4811-4900. https://doi.org/10.5194/essd-14-4811-2022

Lan, X., B. D. Hall, G. Dutton, J. Mühle, J. W. Elkins, and I. J. Vimont. (2022). Long-lived greenhouses gases [in State of the Climate in 2021, Chapter 2: Global Climate]. Bulletin of the American Meteorological Society, 103 (8), S81-S84. https://doi.org/10.1175/BAMS-D-22-0092.1.

Lüthi, D., M. Le Floch, B. Bereiter, T. Blunier, J.-M. Barnola, U. Siegenthaler, D. Raynaud, J. Jouzel, H. Fischer, K. Kawamura, and T.F. Stocker. (2008). High-resolution carbon dioxide concentration record 650,000-800,000 years before present. Nature, Vol. 453, pp. 379-382. doi:10.1038/nature06949.

Woods Hole Oceanographic Institution. (2015). Introduction to ocean acidification. Accessed October 4, 2017.

Lindsey, R. (2009). Climate and Earth's energy budget. Accessed October 4, 2017.

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Climate Change: Atmospheric Carbon Dioxide

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In the past 60 years, carbon dioxide in the atmosphere has increased 100 times faster than it did during the end of the last ice age.

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Wealthy people have disproportionately large carbon footprints and the percentage of the world's emissions they are responsible for is growing, a study has found.

In 2010, the most affluent 10% of households emitted 34% of global CO2, while the 50% of the global population in lower income brackets accounted for just 15%. By 2015 the richest 10% were responsible for 49% of emissions against 7% produced by the poorest half of the world's population.

Aimee Ambrose, a professor of energy policy at Sheffield Hallam University and author of the study published in the journal Science Direct, says cutting the carbon footprint of the wealthiest might be the fastest way to reach net zero.

In terms of energy demand in the UK, the least wealthy half of the population accounts for less than 20% of final demand, less than the top 5% consumes. While their homes may be more energy efficient, high consumers are likely to have more space to heat. They also own and use more luxury items and gadgets.

Ambrose said the cost of living crisis was likely to make those on middle to low incomes reduce their carbon consumption by holidaying in the UK, if at all, and by using less fuel. However, those who consume the most are unlikely to have to make such changes.

"It is much easier for richer consumers to absorb these increases in costs without changing their behaviour," said Ambrose. "Unlike the less wealthy, the thermostat won't be turned down and the idea of not jetting off on a long-haul flight to find some sun is out of the question.

In most countries, before Covid-19, less than half of people reported flying at least once a year while more than half of emissions from passenger aviation were linked to the 1% of people who fly most often.

"In many ways, the rich are being largely insulated from the spike in energy costs," said Ambrose. "But addressing excessive personal consumption is something that isn't on the agenda for the government and policymakers. This is bad news for the planet and our prospects of reaching net zero."

She said the resulting policy neglect of high consumers was a "missed opportunity" to address inequality and opportunities for carbon reduction.

"Price mechanisms may force low-income households to cut back consumption to dangerous levels," Ambrose added. "Moreover, high consumption and large carbon footprints are spatially concentrated in high-income cities and suburbs - while their negative effects, such as air pollution, typically spill over into less affluent areas."

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'Carbon footprint gap' between rich and poor expanding, study finds

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Wealthy people have disproportionately large carbon footprints and the percentage of the world's emissions they are responsible for is growing, a study has found. In 2010, the most affluent 10% of households emitted 34% of global CO2, while the 50% of the global population in lower income brackets accounted for just 15%.

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https://executive-education.nus.edu.sg/programmes/climate-change-and-sustainability-leveraging-carbon-market-initiatives-for-business/?gclid=CjwKCAjw4c-ZBhAEEiwAZ105RY7xR8NDnHDJZByNvl_wI74q94u4O3hk6DQrR5IltKozJ09EE09JxhoCmasQAvD_BwE

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Overview

Sustainability and climate change are now issues that are moving beyond corporate lip service into real world business costs, challenges, and opportunities.

Leaders and managers with some familiarity on climate change would know of the Kyoto Protocol and the Paris Agreement. However, the details and business implications of these treaties may not be well understood by non-specialists.

Many corporates have set climate-neutrality / net-zero targets and will have to decide a pathway towards net-zero. In practice, corporates will need to make step-by-step decisions on the breadth and depth of their greenhouse gas emission reductions (direct, and indirect). They will also need to decide on the role of carbon credits in their transition period, and in their steady state (i.e. offsetting non-abatable emissions in the long-run).

This programme breaks down the issues, and will help participants to understand and to take advantage of climate change opportunities today, and in the near future.

Core Focus

Basics of Climate Change, Policies & Frameworks

Understanding Climate Change

Politics & Economics of Climate Change

UN Climate Framework

Climate Policy Instruments

Corporate DeCarbonisation Strategies

Fundamentals of Net Zero

Role of Verified Carbon Credits (VCCs)

VCC Overview & UN Legal Framework

Responsible Use of VCCs

High-quality credits and markets. Getting to Net Zero

Generating VCCs in the Real World

Deep Dives into the Quality of VCCs

From Project Quality to Price Signals

Connecting the Dots

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Climate Change and Sustainability: Leveraging Carbon Market Initiatives for Business

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Sustainability and climate change are now issues that are moving beyond corporate lip service into real world business costs, challenges, and opportunities. Leaders and managers with some familiarity on climate change would know of the Kyoto Protocol and the Paris Agreement. However, the details and business implications of these treaties may not be well understood by non-specialists.

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https://m.dongascience.com/news.php?idx=52605

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남극의 해빙 면적 측정이 시작된 지 40년 만에 최저면적을 기록했다. 전문가들은 남극 해빙이 1990년대보다 현재 3배나 빠르게 줄고 있으며, 전 세계 해수면 상승을 유발하고 있다고 분석했다.

미국 자연환경 분야 온라인매체인 어스닷컴에 따르면 미국 국립빙설자료센터(NSIDC)의 예비데이터에서 남극의 해빙면적이 지난 22일 약 194만1000㎢로 나타나며 역대 최저기록을 경신했다. 다음날인 23일에는 이보다 더 떨어져 193만7000㎢까지 떨어진 상태다. 이전 최저기록은 2017년 3월 3일 211만㎢였다.

남극의 해빙은 계절에 따라 늘었다가 줄어드는데, 남극의 여름인 2~3월에 가장 축소된다.

북극은 해빙의 빠르게 줄었지만, 상대적으로 남극의 해빙은 크게 변동하지 않았다. 그러나 2016년 해빙이 급격히 줄어든 이후 계속해서 평균보다 낮은 수준을 유지하고 있다.

테드 스캄보스 미국 국립빙설자료센터 수석연구원은 어스닷컷을 통해 "남극의 해빙은 바람세기, 폭풍 빈도, 강설량, 해수온도 등 매우 많은 변수에 영향을 받는다"며 "지난 40년간 해수온도와 바람의 변화에 의해 남극의 특성이 다소 바뀐 것으로 보인다"고 설명했다.

전문가들은 남극 해빙 감소를 기후변화 영향으로 특정짓기 위해서는 지금과 같은 면적 감소 추세가 10년은 더 이어져야 한다고 설명한다. 그러나 기후변화 영향은 이미 남극대륙 곳곳에서 나타나고 있다.

가령 남극의 거대 빙하 중 하나인 스웨이츠빙하는 균열이 곳곳에 나타난 상태다. 이 빙하는 3~5년 내 붕괴돼 전 세계 엄청난 해수면 상승을 초래할 것으로 전망된다.

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남극 해빙 관측이래 최저 면적 기록...전 세계 해수면 상승 경고

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남극의 해빙 면적 측정이 시작된 지 40년 만에 최저면적을 기록했다. 전문가들은 남극 해빙이 1990년대보다 현재 3배나 빠르게 줄고 있으며, 전 세계 해수면 상승을 유발하고 있다고 분석했다. 미국 자연환경 분야 온라인매체인 어스닷컴에 따르면 미국 국립빙설자료센터(NSIDC)의 예비데이터에서 남극의 해빙면적이 지난 22일 약 194만1000㎢로 나타나며 역대 최저기록을 경신했다. 다음날인 23일에는 이보다 더 떨어져 193만7000㎢까지 떨어진 상태다.

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https://terms.naver.com/entry.naver?docId=3582886&cid=58583&categoryId=59179

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미국의 조사연구기관인 퓨리서치센터가 39개 나라 3만 7천 653명을 대상으로 '국제적 위험 요인'을 조사한 결과, 가장 심각한 국제적 위험 요인으로 꼽힌 문제는 기후변화(54%)였다.
기후변화는 시간이 지나면서 기후 상태가 변화하는 것을 말한다. 최근 들어 가장 큰 기후변화로 손꼽히는 문제는 바로 '지구의 온도상승'으로 이는 전 세계의 과학자들이 함께 고민하는 사항이다. 흔히 지구 온난화 현상이라고도 말하는데, 최근에 지구의 온도 상승이 눈에 띄게 심화되고 있기 때문이다. 실례로 지난 20년간은 20세기 중 가장 더운 시기였던 것으로 확인되었다.
이와 같은 온도 상승의 가장 큰 원인은 온실가스의 증가 때문이다. 온실가스는 인류가 산업혁명 이후 발전하는 과정에서 발생한 것이기 때문에 인간의 활동에 의해 지구의 온난화가 가속화 되었다고 볼 수 있다.
한편, 해수면 상승 또한 기후변화의 대표적인 예로 손꼽힌다. 해수면 상승은 지구 온난화와도 깊은 연관이 있는데, 지구의 기온 상승으로 인해 양 극지방의 빙하가 대거 녹아내리고 있기 때문이다. 1961년부터 1993년까지 지구의 평균 해수면은 1.8mm씩 상승하고 있다. 이는 매우 작은 수치라고 여겨질 수 있지만, 남태평양의 투발루와 같은 나라들은 해발고도가 매우 낮기 때문에 약간의 해수면 상승으로도 나라의 존립이 위협받는 만큼 결코 사소한 문제라고 할 수 없는 상황이다.

지구의 온도가 점점 올라가자 공기의 흐름도 바뀌기 시작했는데, 이렇게 되자 더워지는 것 뿐만 아니라, 어떤 지역에서는 평소에 구경할 수 없었던 많은 눈이 내리기도 하며, 비가 오지 않는 지역이었는데 많은 양의 비가 쏟아지는 경우도 발생하고 있다.
이와 같은 변화는 사람 뿐만 아니라 동물과 식물에도 영향을 미친다. 온도 상승으로 북극과 남극의 빙하가 녹시 시작하자, 해수면은 점차 높아졌고 태평양에 있는 작은 섬들은 육지 전체가 물에 잠길 위험에 놓이게 되었다. 이곳에 살던 사람들은 살기 위해 이사를 가야 한다. 또한 기온이 바뀌면 그 기온에서 살 수 있었던 식물과 동물들은 생존이 어렵게 된다. 이처럼 기후 변화는 사람을 포함하여 지구에 있는 모든 생태계에 큰 영향을 미치게 된다.

육지-해양의 온도 변화 그래프 (1880~2000년) 검은색 선은 연간 평균 온도이고, 빨간색 선은 5년 간의 평균 기온이다. 1880년 이후 끊임없이 지구의 온도가 상승하고 있음을 알 수 있다.

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특정 장소의 기후가 시간이 지나면서 점차 변화하는 것. 미국의 조사연구기관인 퓨리서치센터가 39개 나라 3만 7천 653명을 대상으로 '국제적 위험 요인'을 조사한 결과, 가장 심각한 국제적 위험 요인으로 꼽힌 문제는 기후변화(54%)였다. 기후변화는 시간이 지나면서 기후 상태가 변화하는 것을 말한다. 최근 들어 가장 큰 기후변화로 손꼽히는 문제는 바로 '지구의 온도상승'으로 이는 전 세계의 과학자들이 함께 고민하는 사항이다.

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영국·뉴질랜드 연구팀 분석..."폭염피해 특히 과소집계"

"통계분석 체계 미비 저개발국에 체계적 감시체계 도입해야"

가뭄으로 갈라진 샌안토니오 호수 바닥
[로이터=연합뉴스 자료사진. 재판매 및 DB 금지]

(서울=연합뉴스) 전명훈 기자 = 최근 20년 간 발생한 기상이변으로 전세계에서 수십만 명이 사망한 것으로 집계되고 있으나, 이는 실제 피해 상황을 제대로 반영하지 못한 통계라는 지적이 제기됐다.

집중호우·산불 등 다양한 기후 이변 가운데 특히 온난화의 직접 영향을 받는 '장기 폭염'의 피해 상황이 가장 과소집계되고 있다는 분석이다.

27일(현지시간) 영국·뉴질랜드 연구진이 국제학술지 '기후 환경 연구 저널'에 게재한 논문을 보면 장기 폭염·한파·홍수·가뭄·산불·태풍(열대성 저기압) 등 기상이변으로 인한 전 세계 사망자 수는 2000∼2020년에 50만6천770명으로 집계됐다.

태풍(20만1천명)의 사망자 수가 가장 많았고 장기 폭염(15만7천명), 홍수(11만1천명), 가뭄(2만1천300명), 한파(1만4천900명), 산불(1천570명) 등이 뒤를 이었다.

이런 자연재해로 인한 경제적 피해도 같은 기간 2조2천억 달러(약 2천800조원)에 이른다고 연구팀은 추산했다.

연구팀은 특히 이런 유형의 기후 이변은 대부분 지구 온난화의 영향을 크게 받고 있다고 연구팀은 분석했다.

연구팀은 그러나 국제재난데이터베이스(EMDAT)를 기반으로 한 이 통계가 정확하지 않다는 점을 문제로 지적했다.

중저소득 국가는 정확한 통계 분석 체계가 갖춰져 있지 않은 경우가 많아 데이터가 제대로 수집되지 않을 수 있다는 것이다.

이상기후 가운데 이런 문제가 가장 심각한 유형은 장기 폭염이라고 연구팀은 지적했다.

일부 국가에서는 폭염의 정의조차 제대로 수립되지 않았고, 일부 국가는 지역별 검측소를 제대로 갖추지 못한 경우도 많기 때문에 폭염으로 사망해도 제대로 집계되지 않았을 공산이 크다는 것이다.

실제로 EMDAT 데이터에는 2000∼2020년에 전세계에서 발생한 장기 폭염 사망자 15만7천명 가운데 아시아·아프리카·중남미에서 발생한 사망자 수는 전체의 6.3%에 불과한 1만 명이라고 밝히고 있다.

해당 지역 인구가 전체의 85%를 차지하고, 면적도 전체 육지의 60%를 차지한다는 점에서 부자연스러운 수치라고 연구팀은 지적했다.

문제의 통계에는 2003년, 2010년에 각각 기록된 유럽 장기 폭염 사망자 12만5천 명이 포함돼 있는데, 당시 유럽의 습구온도(습도를 반영한 기온)는 28도였다. 아시아 남부에서 거의 매일같이 넘나드는 기온이다.

연구에 참여한 프리데리크 오토 영국 임페리얼칼리지런던 교수는 블룸버그통신에 "이 데이터에 따르면 지금까지 아프리카 대륙에서 기록된 장기 폭염이 딱 11차례 뿐"이라며 "말도 안 된다"고 지적했다.

연구팀은 논문에서 "체계적인 기상이변 감시체계를 구축해야 한다"면서 "기상이변의 피해를 정확히 파악해야 기후 정책이 온난화의 속도를 따라잡을 수 있다"고 강조했다.

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"20년간 전세계 기상이변 사망 50만명...실제 피해는 더 심각" | 연합뉴스

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(서울=연합뉴스) 전명훈 기자 = 최근 20년 간 발생한 기상이변으로 전세계에서 수십만 명이 사망한 것으로 집계되고 있으나, 이는 실제 피해 상황을 제대로 반영하지 못한 통계라는 지적이 제기됐다. 집중호우·산불 등 다양한 기후 이변 가운데 특히 온난화의 직접 영향을 받는 '장기 폭염'의 피해 상황이 가장 과소집계되고 있다는 분석이다.

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https://scholar.google.co.kr/scholar?hl=ko&as_sdt=0%2C5&q=Rising+sea+levels+due+to+global+warming&btnG=#d=gs_qabs&t=1664409682388&u=%23p%3DlqLdk8AhxeQJ

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https://www.climate.gov/news-features/understanding-climate/climate-change-global-sea-level

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Sea level has risen 8-9 inches since 1880, and the rate is accelerating thanks to glacier and ice sheet melt.

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https://futurechosun.com/archives/64712
위의 글에는 산업화 이전보다 1.5도 오를 가능성이 점점 높아지고 이가 계속되면 지구 기온이 1.5도가 넘을 수 있다고 말한다.

https://climate.nasa.gov/ask-nasa-climate/2949/why-milankovitch-orbital-cycles-cant-explain-earths-current-warming/

https://m.blog.naver.com/ksj8599/221853367050
첫 번째 링크는 나사에서 작성한 밀란코비치 주기가 최근 지구온난화를 설명할 수 없는지 말하고 있다. 두 번째 링크는 같은 글의 번역본이다.

https://m.dongascience.com/news.php?idx=15280
위 기사에는 1000년 전 그린란드에 대한 정보가 포함되어 있다.

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https://me.go.kr/home/web/board/read.do;jsessionid=I3lewRa6R+SzhTZSG+eorfOD.mehome1?pagerOffset=1040&maxPageItems=10&maxIndexPages=10&searchKey=&searchValue=&menuId=&orgCd=&boardId=173273&boardMasterId=2&boardCategoryId=&decorator=

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지구온난화 원인과대책

온난화 현상의 이유는 이산화탄소가 너무 많아 오존층의 사이사이를 벌려서 오존층에 구멍을 낸다. 이 구멍으로 햇빛이 오존층으로 걸러지지 않고 바로 들어와서 햇빛의 세기가 오존층에 걸러져 오는 것과 걸러지지 않고 온 것의 차이는 매우 크다. 이 햇빛은 우리의 피부를 상하게 하고, 비가 내리지 않고, 식물들은 말라서 다 죽고 풀을 먹는 동물들이 죽고 육식동물이 죽고 결국 우리 사람도 죽어서 멸망에 이를수 있다.
온난화 현상 자체는 과거에도 있었으나, 여기서는 주로 19세기 후반부터 관측되고 있는 온난화를 가리킨다. 이러한 현대 온난화의 원인은 온실가스의 증가에 있다고 보는 견해가 지배적이다. 산업 발달에 따라 석유와 석탄 같은 화석연료를 사용하고 농업 발전을 통해 숲이 파괴되면서 온실효과의 영향이 커졌다고 본다. 현재 기후변화에 관한 정부간 패널(IPCC)에서 인정한 견해는 19세기 후반 이후 지구의 연평균기온이 0.6℃ 정도 상승했다는 것이며, 20세기 전반까지는 자연 활동이 온난화를 유발했지만 20세기 후반부터는 인류의 활동이 온난화를 유발했다는 것이다.
온난화 현상의 경과
온난화는 1972년 로마클럽 보고서에서 처음 공식적으로 지적되었다. 이후 1985년 세계기상기구(WMO)와 국제연합환경계획(UNEP)이 이산화탄소가 온난화의 주범임을 공식으로 선언하였다. 1988년에는 IPCC가 구성되어 기후 변화에 관한 조사와 연구를 행하고 있다. 1988년 미국항공우주국(NASA)에서 미국 의회에 지구온난화에 대한 발언을 한 것을 계기로 일반인에게도 널리 알려지게 되었다. 지구의 연평균기온은 원래 400년에서 500년 정도를 주기로 약 1.5℃의 범위에서 계속 변화한다. 15세기에서 19세기까지는 비교적 기온이 낮은 시기였으며 20세기에 들어와서는 기온이 오르고 있어서, 어떤 면에서는 기온 상승이 자연스러운 현상일 수도 있다. 하지만 대기 중의 이산화탄소 양은 1800년대에는 280ppm이었으나 1958년에는 315ppm, 2000년에는 367ppm으로 계속 증가하고 있으며 다른 온실기체도 증가하고 있다.
온난화 현상의 원인
온난화의 원인은 아직까지 명확하게 규명되지 않았으나, 온실효과를 일으키는 온실기체가 유력한 원인으로 꼽힌다. 온실기체로는 이산화탄소가 가장 대표적이며 인류의 산업화와 함께 그 양은 계속 증가하고 있다. 이외에도 메테인, 수증기가 대표적인 온실기체다. 특히 현대에 사용하기 시작한 프레온가스는 한 분자당 온실효과를 가장 크게 일으킨다. 또한 인류가 숲을 파괴하거나 환경오염 때문에 산호초가 줄어드는 것에 의해서 온난화 현상이 심해진다는 가설도 있다. 나무나 산호가 줄어듦으로써 공기 중에 있는 이산화탄소를 자연계가 흡수하지 못해서 이산화탄소의 양이 계속 증가한다는 것이다. 이러한 가설 이외에도 태양 방사선이 온도 상승에 영향을 준다거나, 오존층이 감소하는 것이 영향을 준다거나 하는 가설이 있지만 온실효과 이외에는 뚜렷한 과학적 합의점이 존재하지 않는 상태이다.
온난화 현상의 결과
지구의 연평균기온이 계속 올라감으로써 땅이나 바다에 들어 있는 각종 기체가 대기 중에 더욱 많이 흘러나올 것으로 예측된다. 이러한 피드백 효과는 온난화를 더욱 빠르게 진행시킬 것이다. 온난화에 의해 대기 중의 수증기량이 증가하면서 평균강수량이 증가할 것이고 이는 홍수나 가뭄으로 이어질 수 있다. 가장 큰 문제는 해수면이 상승하는 것으로, 기온 상승에 따라 빙하가 녹으면서 이 현상이 일어날 것으로 예측된다. 2000년 7월 NASA는 지구온난화로 그린란드의 빙하가 녹아내려 지난 100년 동안 해수면이 약 23cm 상승하였다고 발표하였다. 그린란드의 빙하 두께는 매년 2m씩 얇아지고 있으며 이 때문에 1년에 500억 톤 이상의 물이 바다로 흘러 해수면이 0.13mm씩 상승하고 있다는 것이다. 이러한 해수면 상승은 섬이나 해안에 사는 사람들의 생활에 영향을 미칠 것이며 특히 해안에 가까운 도시에는 물에 잠길 수 있는 큰 위험에 빠진다.
지구온난화가 계속 잃어난다면 이런 현상이 많이 일어난다.
이렇게 지역이 사막화나 빙하가 녹으면 동물들도 살곳이 없어진다.
북극곰, 일각돌고래. 흰 돌고래, 북극여우 등이 죽어간다.
또 우리 사람들이 살아갈곳들도 줄어든다. (빙하가 녹아 바닷물이 넘쳐나육지에 들어온다.
같이 따라오는 이상기후
지구온난화가 오면 역시 이상기후도 오는데 이상기후도 역시 지구온난화 못지 않게 매우 사람에게 해를 준다.
이상기후의 최고 요인은 지구 온난화현상이랍니다. 지구 온난화현상이란 지구의 오존층이 얇아져서 햇빛이 너무 많이 들어올 뿐만 아니라 지구 내의 이산화탄소가 늘어나 이 기체의 온실효과 때문에
지구가 너무 더워지고 자외선때문에 피해를 보는 현상을 말하게 됩니다.요즈음의 거의 모든 이상기후는 이 현상에서 비롯된 것이다.
이상기후의 종류와 영향
1. 지구온난화때문에 적도 부분은 오존층이 더 두꺼워져 차가워지고 극지방은 자꾸 구멍이 뚫려서 빙하가 녹고 온도가 올라가고 있는데요... 이렇면서 이 두지방의 온도차가 줄어 대류현상이 줄어들어 바람또한 줄어들고 있는데요 이것때문에 바람에너지가 무한 에너지가 되지 못한 피해가 있습니다.
2. 스모그 현상이라고 안개 속에 매연이 포함되어서 먼지 안개가 생겨서 엄청난 피해가 있는데 이 현상은 사람들의 시야를 가릴 뿐만 아니라 호흡기 질환을 일으키는 무서운 현상이다.
3. 사막화현상 : 이 현상은 지구가 2080년도에 모든 생물의 70%가 없어지리라고 되는 무시무시한 현상인데요, 중위도 지방의 습지가 오염된 물과 뜨거워진 기후 오염된 공기때뭄에 말라서 황폐화되는 현상을 말해요. 이게 사실이라면 끔직하게 된다.
4. 엘니뇨 라니냐 현상 :
엘리뇨 현상 : 바다의 기온이 평균기온보다 높아져 바다의 생물체가 멸종하는 대재앙을 말합니다.
라니냐 현상 : 엘리뇨와 세트로써 서태평양은 고온이 되고, 동태평양은 저온이 되는 바다를 말해 지금 우리나라의 어획량과 해양 생태계에 무지막자한 피해를 주고 있습니다. 네 이제는 이상기후에 대한 대책을 말슴 드리겠습니다. 먼저 돈이 많은 대기업에서는 돈을 이런 지구과학 연구단체에 많이 기증해서연구를 돕고 있고 정부는 이런 대기업들을 후원하며 세계에 우리나라의 대기업 연구를 알리는 것이다.
시민들이 할 수 있는 일이 가장 많답니다. 시민들은 스프레이나 에어컨 사용을 줄여서 프레온 가스 배출량을 줄여 공기중의 이산화탄소 함량을 줄일 수 있고, 나무심기 운동을 해 공기중 용존 산소량 을 늘려 스모그 현상도 막고 지구온난화도 막는다.

에너지와 자원 절약의 실천이다. 개인이 국가적인 대책방안은 하지 못하더라도 가정 및 직장에서의 냉·난방 에너지 및 전력의 절약, 수도물절약, 공회전 자제, 대중교통 이용, 카풀(car pool)제 활용, 차량 10부제 동참 등으로 지구를 온난화로부터 지킬 수 있다.

환경친화적 상품으로의 소비양식 전환이다. 동일한 기능을 가진 상품이라면 환경오염 부하가 적은 상품, 예를 들면, 에너지효율이 높거나 폐기물 발생이 적은 상품을 선택하는 것이 최선의 방법이다. 이러한 소비패턴이 정착될 경우 생산자도 제품생산시 소비성향을 고려하게 되므로, 장기적으로는 경제구조 자체가 환경친화적으로 바뀌게 된다. 고효율등급의 제품 및 환경마크 부착제품을 구입한다.

폐기물 재활용의 실천이다. 온실가스 중의 하나인 메탄은 주로 폐기물 매립 처리과정에서 발생하며 재활용이 촉진되면 매립지로 반입되는 폐기물량이 감소하므로 메탄 발생량도 따라서 감소한다. 또한 폐기물 발생량이 감소하면 소각량이 감소하여 소각과정에서 발생하는 이산화탄소 배출량도 감소한다. 폐지 재활용은 산림자원 훼손의 둔화를 통해 온실가스 감축에 기여한다.

나무를 심고 가꾸기를 생활화한다. 나무는 이산화탄소의 좋은 흡수원이다. 예를 들어, 북유럽과 같이 산림이 우거진 국가는 흡수량이 많아 온실가스 감축에 큰 부담을 느끼지 않는 것이 좋은 예인 것이다.

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환경부 - 지구온난화 원인과대책

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지구온난화 원인과대책 온난화 현상의 이유는 이산화탄소가 너무 많아 오존층의 사이사이를 벌려서 오존층에 구멍을 낸다. 이 구멍으로 햇빛이 오존층으로 걸러지지 않고 바로 들어와서 햇빛의 세기가 오존층에 걸러져 오는 것과 걸러지지 않고 온 것의 차이는 매우 크다. 이 햇빛은 우리의 피부를 상하게 하고, 비가 내리지 않고, 식물들은 말라서 다 죽고 풀을 먹는 동물들이 죽고 육식동물이 죽고 결국 우리 사람도 죽어서 멸망에 이를수 있다.

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요약 특정 장소의 기후가 시간이 지나면서 점차 변화하는 것.

미국의 조사연구기관인 퓨리서치센터가 39개 나라 3만 7천 653명을 대상으로 '국제적 위험 요인'을 조사한 결과, 가장 심각한 국제적 위험 요인으로 꼽힌 문제는 기후변화(54%)였다.
기후변화는 시간이 지나면서 기후 상태가 변화하는 것을 말한다. 최근 들어 가장 큰 기후변화로 손꼽히는 문제는 바로 '지구의 온도상승'으로 이는 전 세계의 과학자들이 함께 고민하는 사항이다. 흔히 지구 온난화 현상이라고도 말하는데, 최근에 지구의 온도 상승이 눈에 띄게 심화되고 있기 때문이다. 실례로 지난 20년간은 20세기 중 가장 더운 시기였던 것으로 확인되었다.
이와 같은 온도 상승의 가장 큰 원인은 온실가스의 증가 때문이다. 온실가스는 인류가 산업혁명 이후 발전하는 과정에서 발생한 것이기 때문에 인간의 활동에 의해 지구의 온난화가 가속화 되었다고 볼 수 있다.
한편, 해수면 상승 또한 기후변화의 대표적인 예로 손꼽힌다. 해수면 상승은 지구 온난화와도 깊은 연관이 있는데, 지구의 기온 상승으로 인해 양 극지방의 빙하가 대거 녹아내리고 있기 때문이다. 1961년부터 1993년까지 지구의 평균 해수면은 1.8mm씩 상승하고 있다. 이는 매우 작은 수치라고 여겨질 수 있지만, 남태평양의 투발루와 같은 나라들은 해발고도가 매우 낮기 때문에 약간의 해수면 상승으로도 나라의 존립이 위협받는 만큼 결코 사소한 문제라고 할 수 없는 상황이다.

지구의 온도가 점점 올라가자 공기의 흐름도 바뀌기 시작했는데, 이렇게 되자 더워지는 것 뿐만 아니라, 어떤 지역에서는 평소에 구경할 수 없었던 많은 눈이 내리기도 하며, 비가 오지 않는 지역이었는데 많은 양의 비가 쏟아지는 경우도 발생하고 있다.
이와 같은 변화는 사람 뿐만 아니라 동물과 식물에도 영향을 미친다. 온도 상승으로 북극과 남극의 빙하가 녹시 시작하자, 해수면은 점차 높아졌고 태평양에 있는 작은 섬들은 육지 전체가 물에 잠길 위험에 놓이게 되었다. 이곳에 살던 사람들은 살기 위해 이사를 가야 한다.

또한 기온이 바뀌면 그 기온에서 살 수 있었던 식물과 동물들은 생존이 어렵게 된다. 이처럼 기후 변화는 사람을 포함하여 지구에 있는 모든 생태계에 큰 영향을 미치게 된다.

육지-해양의 온도 변화 그래프 (1880~2000년)
검은색 선은 연간 평균 온도이고, 빨간색 선은 5년 간의 평균 기온이다. 1880년 이후 끊임없이 지구의 온도가 상승하고 있음을 알 수 있다.

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특정 장소의 기후가 시간이 지나면서 점차 변화하는 것. 미국의 조사연구기관인 퓨리서치센터가 39개 나라 3만 7천 653명을 대상으로 '국제적 위험 요인'을 조사한 결과, 가장 심각한 국제적 위험 요인으로 꼽힌 문제는 기후변화(54%)였다. 기후변화는 시간이 지나면서 기후 상태가 변화하는 것을 말한다. 최근 들어 가장 큰 기후변화로 손꼽히는 문제는 바로 '지구의 온도상승'으로 이는 전 세계의 과학자들이 함께 고민하는 사항이다.

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https://n.news.naver.com/article/031/0000697769?sid=101

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개인·보험산업·정부 등 기상이변 대비할 방안 제시 최근 수도권과 중부지방을 중심으로 기록적인 폭우가 발생했다. 서울 동작구의 경우 지난달 8일 오후 9시 5분에 시간당 141.5mm가 측정돼 115년 만에 서울 지역 역대 시간당 최대 강우량을 기록했다.

앞으로 이 같은 기상이변이 기후변화로 인해 더욱 빈번해질 것으로 예상되는 가운데 주요 위험으로 인식해 대비 방안을 세워야 한다는 지적이 나온다.

임준 보험연구원 연구위원은 18일 발표한 '기후변화로 인한 홍수재해 대비 방안' 리포트를 통해 개인과 보험산업, 정부 등이 향후 유념해야 할 내용을 다뤘다.

보험연구원이 기후변화로 인한 홍수재해에 대한 개인과 보험산업, 정부 등이 마련할 대비 방안을 제안했다. 사진은 지난달 9일 서울 서초구 서초대로에 전날 비로 침수된 차들이 도로에 엉켜있는 모습. [사진=뉴시스]

우선 임 연구위원은 그동안 자연재해가 개인 차원에서 대비해야 하는 주요 위험으로 여겨지지 않았지만, 보험 소비자들이 향후 고령화와 마찬가지로 대비가 필요하다고 주장했다. 현재 사후 복구 재원으로 정부의 재난 기금에 주로 의존하고 있어, 이재민의 완전한 복구에 한계가 있다는 판단이다.

특히 기후변화로 인해 홍수재해의 빈도와 심도가 증가하게 되면 홍수재해의 사후 복구에 있어서 국가 재정의 한계는 분명해질 것으로 봤다. 이에 보험 가입 등을 통한 개인 차원 대비의 중요성이 부각될 것으로 예상했다.

임 연구위원은 "고령화의 경우 국민연금과 개인연금의 공사연계 체계를 구축하고 있다"면서 "홍수재해도 사후 복구 재원 조달에 있어서 정부와 개인의 협력 체계를 사전에 구축할 필요가 있다"고 강조했다.

보험산업은 기후변화로 인한 새로운 시장 접근 기회가 생기면서 위험관리자와 사회안전망으로서의 역할에 있어서 더 큰 책임을 요구받게 될 것으로 보인다.

임 연구위원은 보험업계가 자연재해와 관련된 위험을 평가해 개인에게 전달하는 역할을 수행해야 한다고 했다. 각 개인이 처한 위험은 보통 보험료의 수준을 통해 전달된다.

보험산업이 위험관리자로서의 역할을 수행하기 위해 자연재해 관련 위험을 제대로 평가할 수 있는 기술력 제고도 필요하다고 했다. 이를 위해 자연과학 기반의 위험평가 전문인력을 육성해야 한다고 판단했다.

실제로 독일 뮤니크리는 회사 내에 과학연구 부서인 'Scientific Research Unit'를 신설하고, 기상학자와 지질학자를 고용해 자연재해 관련 위험 예측 방법론을 개발했다.

임 연구위원은 정부의 경우 홍수재해 대비에 있어 개인이나 보험산업이 가진 한계를 보완하기 위해 민관 손실 분담과 보험료 간접 지원 등 다양한 지원 정책을 추진할 필요가 있다고 제언했다.

홍수재해의 사후 복구에 대한 민영보험의 역할을 확대하기 위해서는 공급·수요 측면에서 정부의 활성화 정책이 필요하다고 했다.

임 연구위원은 "공급 측면은 보험업계와 정부가 협력해 손실을 분담하는 민관협력체계를 구축해야 한다"면서 "수요 측면의 경우 보험 가입률 제고를 위해 직접 지원과 간접 지원 등 2가지 방식으로 보험료 지원이 이뤄져야 한다"고 강조했다.

또 "위험에 대한 근본 대책은 위험 자체를 줄이는 것이므로 장기적으로는 간접 지원 중심의 정책을 추진하는 것이 바람직하다"고 제안했다.

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보험硏 "기상이변 빈번, 고령화처럼 홍수재해도 대비해야"

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개인·보험산업·정부 등 기상이변 대비할 방안 제시 최근 수도권과 중부지방을 중심으로 기록적인 폭우가 발생했다. 서울 동작구의 경우 지난달 8일 오후 9시 5분에 시간당 141.5mm가 측정돼 115년 만에 서울 지역 역대 시간당 최대 강우량을 기록했다. 앞으로 이 같은 기상이변이 기후변화로 인해 더욱 빈번해질 것으로 예상되는 가운데 주요 위험으로 인식해 대비 방안을 세워야 한다는 지적이 나온다.

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https://www.un.org/en/climatechange/science/causes-effects-climate-change

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https://www.nationalgeographic.com/environment/article/global-warming-causes

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Human influence is rapidly changing the climate.

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https://www.oecd.org/env/reducinggreenhousegasemissionsindevelopedcountries.htm

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Remarks by Angel Gurría, OECD Secretary-General, at the Informal Ministerial Meeting on Climate Change

New York, Saturday 19 September 2009

Minister Hedegaard, Ministers,

It is an honour to join this distinguished gathering, at a moment when we are facing such critical challenges.

We need action to reduce greenhouse gas emissions and we need it now. For those who want to use the economic crisis to justify delaying action, our message is that it doesn't make economic sense, especially given the costs and risks of inaction. Without significant new policy action, the OECD projects that world GHG emissions would increase by about 70% by 2050 and continue to grow thereafter. This could lead to a rise in world temperatures of 4°C above preindustrial levels, and possibly 6°C, by 2100.

We can just imagine the social and human consequences. The economic cost would also be immense. And we have all seen recent reports suggesting that climate change might be occurring faster than earlier thought.

By acting now, we may have 10 to 15 years "breathing space" to build a full-fledged global carbon market. If we do that, it would cost just about one-tenth of a percentage point of world annual GDP growth between 2012 and 2050 to achieve moderately ambitious climate targets. Put differently, this would mean a 4% reduction in GDP in 2050 compared to a scenario where no policy action is taken. Bear in mind that over the same period world GDP is projected to grow by more than 250%.

If action is delayed, and GHG emissions continue to accumulate, the cost of reducing concentrations to an acceptable level later might well be much higher.

Now is crunch time. I am aware of the difficult choices that lie ahead. But I believe the elements of a deal are there. And we see our role as providing the tools to inform policy choices and to help you achieve an ambitious agreement in Copenhagen.

Let me introduce the perspective of the OECD. Yesterday, we presented our study on the Economics of Climate Change Mitigation. It contains timely answers to some of the important questions under discussion today.

Are current efforts & pledges sufficient?

The good news is that there are signs that policies are changing. Most developed countries have declared or suggested possible mid-term emission reduction targets. Japan's new government has just increased the ambition of their target. Important draft legislation is being prepared in many countries to back-up these targets. Some non-Annex I countries are also coming forward - including Korea, Mexico and South Africa. Other major emitters, such as China, are putting in place increasingly ambitious policies to reduce their emissions. These are welcome developments.

However, most of these responses are still not ambitious enough. The combined effects of the developed country targets would lead, according to our analysis, to only 8 to 14% reduction in their emissions by 2020 compared with 1990. Clearly, this falls short of the 25 to 40% reduction that, according to the IPCC, developed countries must achieve to put emissions on a pathway that would prevent temperatures from rising by more than 2°C. So, more ambitious action is needed.

Developed countries have a responsibility not only to take the lead on emissions, but also to significantly scale-up financing to support mitigation action in developing countries, as well as adaptation efforts. This has been a major stumbling block in the negotiations, but there are signs they are also moving on that front. The recent EC Communication is a positive step forward.

Clearly, carbon markets will have a strong role to play, but public financing is also critical. OECD has been tracking bilateral support to mitigation for over a decade, and we are examining ways to better harness the carbon market and private investments, to create innovative financing flows. We are also looking at how best to govern this new scaled-up financing to ensure it is in line with developing country development plans and objectives.

We all recognize the legitimacy of their development aspirations and we all need to strive to make action on climate change compatible with or better still, supportive of, development goals. This is possible, but everyone has to do its part. Incidentally, in terms of actions that can be taken, our recent analysis finds that removing fossil fuel subsidies could reduce global GHG emissions by 10% in 2050, while boosting economic growth.

Are mitigation efforts comparable?

Both developed and developing countries have indicated that they will do their "fair share" of GHG mitigation in order to reach a successful agreement in Copenhagen. The difficult part is working out what exactly is a "fair share".

On Monday, a number of Ministers - including many here - will discuss the thorny issue of comparability of effort at a Meeting of the OECD Roundtable on Sustainable Development.

As background to that meeting, we have compared the costs of declared country targets using a range of metrics, reflecting some of the common guiding principles of capability, responsibility and potential.

Comparing efforts amongst countries is not straightforward - both the metrics used and also the assumptions can significantly impact on how countries compare.

In terms of one such metric - namely GDP costs - we found that the current declared targets of developed countries are roughly similar in terms of costs across countries, with perhaps slightly higher GDP losses expected in New Zealand and Australia and in countries using carbon more intensively, such as Russia and some Eastern European countries. These results are based on the technical assumption that there is linking of emissions trading schemes amongst countries. This lowers the overall costs of action, especially in Europe and Japan.

Based on other principles for sharing emission reductions the picture shifts. For example, combining analysis of mitigation potential, ability to pay (GDP/capita), and a measure of responsibility (GHG/capita), results suggest a need for greater action by Australia, Canada, Russia, Ukraine and the US.

Addressing carbon leakage and competitiveness concerns

Concerns about "comparable effort" amongst developed countries are driven by the need to ensure that commitments taken on in Copenhagen will not put their economy at a competitive disadvantage. I truly understand this concern! But let's keep this in perspective.

Fears that ambitious climate policy action will lead to a loss in competitiveness for key sectors, or to carbon leakage, are often exaggerated. I am not downplaying the structural adjustments that will be needed to move to a low-carbon economy. Energy-intensive industries will be particularly impacted. But unless it is only a very few countries that take action against climate change, carbon leakage rates and competitiveness effects of climate policies will be small.

Let me present an illustrative example. If the EU were to cut emissions by 50% by 2050, with no other countries taking any action, our analysis suggests that almost 12% of their emissions reductions would be "leaked", or offset, through increased emissions in other countries. Instead, if the number of countries participating was expanded to notably include all industrialized countries, not just EU countries, the GHG leakage rate would reduce to just 2%.

Before concluding, let me turn to some of the options being considered to counter potential competiveness or carbon leakage effects. Let me sound a word of caution here. Recent OECD analysis has found that Border Tax Adjustments (BTAs), for example, are costly to both the countries that implement them and their trading partners. While they can reduce carbon leakage, they have little effect on losses in value-added to affected industries. They are also administratively burdensome to implement and may lead to trade retaliation.

Minister Hedegaard, Ministers,

The window of opportunity is limited.

Broader and deeper participation by countries and sectors in GHG mitigation will be critical to reach a successful agreement in Copenhagen.

Rigorous analysis for comparing different levels of effort is available - by OECD and by others. It is meant to help countries put their own proposed efforts into perspective.

At the same time, we need to recognize that there is no single, objective answer to the question "what is a fair share". What is important is to scale-up our collective effort, and find ways to make a low carbon society compatible with economic growth. This can be done, if the right policies are in place. This is the main message I would like to leave you with today.

I hope you have a productive discussion. Thank you very much.

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Reducing greenhouse gas emissions in developed countries - OECD

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Remarks by Angel Gurría, OECD Secretary-General, at the Informal Ministerial Meeting on Climate Change New York, Saturday 19 September 2009 Minister Hedegaard, Ministers, It is an honour to join this distinguished gathering, at a moment when we are facing such critical challenges. We need action to reduce greenhouse gas emissions and we need it now.

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탄소 배출량도 빈부격차…”부유층이 2배 이상” | 연합뉴스

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[앵커]
기상이변의 원인으로 전문가들은 지구온난화를 지목하고 있습니다.
자연스레 온실가스인 이산화탄소 배출문제로 이어지게 되는데요.
...

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이희연 환경대학원 교수님께서 작성한 파일이다. 개도국이 기후변화 대응에 취약하다는 점이 나온다. 이에 비추어보면 탄소배출을 규제하여 기후변화를 막는 것이 장기적으로 개도국에게 더 좋은 정책이다.

https://m.blog.naver.com/gp3project/10105889547
위 글에도 비슷한 내용이 있다.

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김용준, 이영인, 정은찬

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김용준, 이영인, 정은찬

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(82) 지구의 기후 시스템은 어떻게 작동하는가

2021년 1월, 사시사철 더운 아프리카 사하라와 중동 사우디아라비아 사막의 기온이 영하로 떨어지고 눈이 쌓였다. 세계 곳곳에서 기상 이변이 일어날 때마다 기후 변화나 기후 위기가 같이 소환된다. 지구의 기후 시스템은 어떻게 작동하기에 기후가 변한다는 것일까.

기후는 어떤 지역에서 오랜 시간 반복되는 평균적인 기상 현상을 뜻한다. 보통 어느 지역에서 30년 이상 관측한 기온, 습도, 강수량, 풍향, 풍속 등의 날씨 정보를 평균한 값이다. 하루 반짝 더운 것은 기상 이변이고 여름의 평균 기온이 올라가는 것은 기후 변화다.

지구의 연평균 기온은 약 15도로 일정하다. 기온이 일정하다는 것은 들어온 것만큼 다시 나가서 남는 열이 없다는 걸 의미한다. 이 상태를 복사평형이라고 한다. 만약 지구가 달처럼 대기가 없다면 낮 동 안 흡수된 에너지가 모두 방출되어 낮과 밤의 기온 차이가 크고 평균 기온도 낮아질 것이다. 다행히 지구는 이불 같은 고마운 대기에 둘러싸여 더높은 온도에서 좀 더 복잡한 과정으로 복사평형을 이루고 있다.

지구에 들어오는 태양복사에너지를 100%라고 할 때, 약 30%는 대기와 지표에서 반사되어 우주로 나가고 20%는 대기, 50%는 지표에 흡수된다. 데워진 지표는 지구복사에너지를 방출하고 그 중 극히 일부만 우주로 바로 나가고 대부분 대기로 흡수된다. 대기에 흡수된 에너지는 다시 대기를 데우고 우주와 지표로 방출되는데 이를 온실 효과라 한다. 대기와 지표에서 우주로 방출하는 에너지를 모두 합하면 70%로, 지구로 들어온 70%의 태양복사에너지와 같은 양이 되어 복사평형이 되고 평균 기온이 일정하게 유지된다. 그런데 대기중에 이산화 탄소 같은 온실가스가 많아지면, 지표에서 방출되는 에너지를 대기가 더 많이 흡수하고 다시 지표에 들어오는 에너지가 더 많아져 지구의 평균 기온은 높아진다. 이를 지구온난화 현상이라고 한다.

지구 전체적으로는 복사평형을 이루지만 적도 부근은 에너지가 남고 극지방은 에너지가 부족해 저위도의 남는 에너지를 고위도 지역으로 운반하는 지구 전체적인 순환이 일어난다. 지구의 기후 시스템에서는 복사평형, 대기 대순환, 해수의 순환이 끊임없이 일어나고 지구의 평균 기온이 일정하게 작동하고 있다.

지구의 기후 시스템과 평균 기온을 변화시키는 원인으로는 자연적인 요인과 인위적인 요인이 있다. 자연적인 원인으로 지구에 들어오는 태양복사에너지의 양이 변하면 지구의 평균 기온도 변하게 된다. 태양 흑점 수의 변화, 화산 폭발도 한 요인이다.

인위적인 기후 변화 요인에는 대기 중 이산화 탄소로 대표되는 온실가스 증가가 있다. 과거 기후를 분석해 보면 화산 폭발, 대규모 산불이 발생해 대기 중 이산화 탄소 양이 자연적으 로 변해왔다는 것을 알 수 있다. 그러나 과거 80만 년 동안 대기중의 이산화 탄소 농도는 180~280ppm이었지만 18세기 산업혁명 이후 최근 200년 동안 급속히 증가해 2019년에 400ppm을 초과했고, 과학자들은 앞으로 이산화 탄소 농도가 450ppm이 된다면 연평균 기온이 2도 이상 상승할 것으로 예상한다. 인류의 화석연료 사용이 늘어났기 때문이다. 게다가 이산화 탄소를 산소로 바꿔주는 산림은 줄고 있다. 그 외 온실가스로는 메테인, 이산화질소, 오존, 프레온가스 등이 있다. 특히 메테인은 온실 효과가 이산화 탄소 보다 약 30배나 높은데 소나 돼지 같은 가축의 사육으로 그 양이 증가하고 있다.

기후 변화는 일반적으로 '인간이 일으킨 기후 변화'를 의미한다. 인간 활동으로 일어나는 기후 변화는 급격한 변화이기 때문에 우리에게 위협적인 존재다. 기후 변화는 인류가 직면한 거대한 재앙으로 긴박함과 중요성을 강조한 '기후 위기'란 용어가 점점 더 널리 사용되고 있다. 기후 위기에 맞서 우리가 할 수 있는 일을 적극적으로 찾아내 하는 것은 이제 선택이 아닌 필수다.
√ 기억해주세요

지구의 연평균 기온은 약 15도로 일정하다. 기온이 일정하다는 것은 들어온 것만큼 다시 나가서 남는 열이 없다는 걸 의미한다. 이 상태를 복사평형이라고 한다. 만약 지구가 달처럼 대기가 없다면 낮 동 안 흡수된 에너지가 모두 방출되어 낮과 밤의 기온 차이가 크고 평균 기온도 낮아질 것이다. 다행히 지구는 이불 같은 고마운 대기에 둘러싸여 더높은 온도에서 좀 더 복잡한 과정으로 복사평형을 이루고 있다.

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[과학과 놀자] 기후 변화 주요 원인은 대기 중 온실가스의 증가...80만년간 일정하게 유지되다 산업혁명 이후 급증 | 생글생글

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(82) 지구의 기후 시스템은 어떻게 작동하는가 2021년 1월, 사시사철 더운 아프리카 사하라와 중동 사우디아라비아 사막의 기온이 영하로 떨어지고 눈이 쌓였다. 세계 곳곳에서 기상 이변이 일어날 때마다 기후 변화나 기후 위기가 같이 소환된다. 지구의 기후 시스템은 어떻게 작동하기에 기후가 변한다는 것일까. 기후는 어떤 지역에서 오랜 시간 반복되는 평균적인 기상 현상을 뜻한다.

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https://scholar.google.co.kr/scholar?hl=ko&as_sdt=0%2C5&q=a+change+in+the+weather&btnG=#d=gs_qabs&t=1664410834735&u=%23p%3DnYsmIOQGXLcJ

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https://scholar.google.co.kr/scholar?hl=ko&as_sdt=0%2C5&q=the+cause+of+rising+global+temperatures&btnG=#d=gs_qabs&t=1664411277913&u=%23p%3Dgl7a3PaxsEQJ

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김용준, 이영인, 정은찬

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김용준, 이영인, 정은찬

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탄소 배출량도 빈부격차..."부유층이 2배 이상"

[앵커]

기상이변의 원인으로 전문가들은 지구온난화를 지목하고 있습니다.

자연스레 온실가스인 이산화탄소 배출문제로 이어지게 되는데요.

전 세계적으로 탄소감축에 대한 공감대가 형성되는 가운데 이산화탄소 배출량에 있어 부유층이 더 큰 영향을 준다는 보고가 나왔습니다.

김효섭 PD입니다.

[리포터]

태풍에 폭염 그리고 대형 화재까지.

지구는 기상변화에 따른 잇단 부작용으로 심한 몸살을 앓고 있습니다.

전문가들은 그 원인으로 지구온난화를 지목합니다.

"만약 지구의 온도 상승을 파리협정에 따라 1.5도로 제한할 수 있다면 위험에 처하는 종은 10% 정도에 국한될 것입니다."

지구온난화를 초래하는 대표적인 온실가스가 바로 이산화탄소입니다.

최근 이산화탄소 배출에 있어서도 빈부격차가 존재한다는 연구결과가 발표됐습니다.

국제구호개발단체 옥스팜과 스톡홀름환경연구소는 탄소 불평등 시대라는 보고서를 통해 이같이 밝혔습니다.

보고서에 따르면 상위 1% 부유층이 1990년부터 2015년까지 배출한 이산화탄소량은 전 세계 이산화탄소 배출량의 15%를 차지했고 이는 하위 50% 빈곤층이 배출한 양의 두 배가 넘는 수치입니다.

기간별 이산화탄소 배출량을 봐도 최근 25년간 배출량이 이전 140년 동안 배출됐던 양과 맞먹을 정도로 급증한 것으로 나타났습니다.

원인으로는 연료효율성이 떨어지는 SUV의 증가와 코로나19로 침체된 경기 부양을 위한 각국의 정책이 지목됐습니다.

국제사회는 탄소 배출을 줄이는 것과 관련해 각국 정부에 지속적인 동참을 강조하고 있습니다.

"우리는 향후 10년간 2010년의 45% 수준으로 탄소 배출을 줄여 이번 세기 중반에는 순배출량 제로에 도달하는 것을 보여줘야 합니다."

연합뉴스TV 김효섭입니다.

연합뉴스TV 기사문의 및 제보 : 카톡/라인 jebo23

(끝)

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탄소 배출량도 빈부격차..."부유층이 2배 이상"

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탄소 배출량도 빈부격차..."부유층이 2배 이상" [앵커] 기상이변의 원인으로 전문가들은 지구온난화를 지목하고 있습니다. 자연스레 온실가스인 이산화탄소 배출문제로 이어지게 되는데요. 전 세계적으로 탄소감축에 대한 공감대가 형성되는 가운데 이산화탄소 배출량에 있어 부유층이 더 큰 영향을 준다는 보고가 나왔습니다. 김효섭 PD입니다. [리포터] 태풍에 폭염 그리고 대형 화재까지. 지구는 기상변화에 따른 잇단 부작용으로 심한 몸살을 앓고 있습니다.

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https://m.search.naver.com/p/crd/rd?m=1&px=67&py=2256&sx=67&sy=336&p=hzi16wprc%2BGss6AnNi4ssssssI4-034253&q=%ED%83%84%EC%86%8C%EB%B0%B0%EC%B6%9C+%EA%B7%9C%EC%A0%9C&ie=utf8&rev=1&ssc=tab.m.all&f=m&w=m&s=w4jvdFgJSFYO0VHZZacMdg%3D%3D&time=1664513333026&abt=%5B%7B%22eid%22%3A%222%22%2C%22vid%22%3A%221%22%7D%2C%7B%22eid%22%3A%22SHOP-MAB%22%2C%22vid%22%3A%2215%22%7D%5D&a=web_gen*w.link&r=1&i=a00000fa_c249424fcd7120c8ab2a5bfc&u=https%3A%2F%2Fwww.hankyung.com%2Feconomy%2Farticle%2F2022060741901&cr=3