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

# data[].attributes.attachment_link.readable_text
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

# data[].attributes.attachment_link.description
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.

# data[].attributes.body
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.body
https://www.quora.com/Why-is-polar-ice-melting-so-much-if-the-temperature-has-risen-around-2-degrees-and-the-average-temperature-at-the-poles-staying-relatively-the-same

# data[].attributes.attachment_link.title
Why is polar ice melting so much if the temperature has risen around 2 degrees and the average temperature at the poles staying relativel...

# data[].attributes.attachment_link.description
Answer (1 of 7): The global mean temperatures don't vary much where people live and have their CO2 emissions for vegetation and grasses to feast on, because CO2 is more massive than air and tends to sink to the surface, but at the poles the Earth's wobble(s) and nutation(s) affect insolation at t...

# data[].attributes.body
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.body
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.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/

# 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.body
https://m.dongascience.com/news.php?idx=34386

# 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
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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북극곰 개체수 - WWF 북극 - https://www.arcticwwf.org/wildlife/polar-bear/polar-bear-population/

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

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https://www.ucsusa.org/resources/co2-and-ocean-acidification

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CO2 and Ocean Acidification: Causes, Impacts, Solutions

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Rising CO2 concentrations in the atmosphere are changing the chemistry of the ocean, and putting marine life in danger.

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위키백과(위키百科, IPA: [ɥikçibɛ̝k̚k͈wa̠], [ykçibɛ̝k̚k͈wa̠] ( )) 또는 위키피디아( 영어: Wikipedia, IPA: [ˌwɪkɪˈpiːdɪə] ( ))는 누구나 자유롭게 쓸 수 있는 다언어판 인터넷 백과사전이다.[2] 2001년 1월 15일 지미 웨일스와 래리 생어가 창립하였으며[3], 대표적인 집단 지성의 사례로 평가받고 있다.[4]

위키백과는 자유 저작물을 보유하고 상업적인 광고가 없으며 주로 기부금을 통해 지원을 받는 비영리 단체인 위키미디어 재단에 의해 소유되고 지원을 받고 있다. 2021년 기준으로 영어판 약 600만여 개, 한국어판 약 539,895개를 비롯하여 300여 언어판을 합하면 전체 위키백과의 일반 문서(넘겨주기와 막다른 문서 제외) 수는 5,500만 개 이상이며, 한 달 순수 방문자 수는 약 17억명이다. 위키백과의 저작권은 크리에이티브 커먼즈 라이선스(CCL)와 GNU 자유 문서(GFDL)의 2중 라이선스를 따른다. 두 라이선스 모두 자유 콘텐츠 를 위한 것으로 일정한 요건을 갖추면 사용에 제약을 받지 않는다.

위키백과 이전에도 온라인 백과사전을 운영하려는 여러 시도들이 있었으나 실패하였다. 위키백과 영어판은 전문가들이 작성했던 백과사전인 누피디아(지금은 존재하지 않음)에서 비롯하였다. 누피디아는 웹 포털 회사인 보미스가 2000년 3월 9일에 개시하였다. 보미스의 CEO였던 지미 웨일스와 편집장 래리 생어는 누피디아의 글들을 오픈 콘텐츠로 제시하기로 하였고 리처드 스톨먼이 주도한 GNU 자유 문서 라이선스로 제공하였다. 누피디아는 그리 성공적이지 않았고, 지미 웨일스와 래리 생어는 누구나 참여할 수 있는 백과사전으로 위키백과를 개설하였다. 생어는 모두의 백과사전이라는 목표를 분명히 하기 위해 이름에 위키를 넣었다. 2001년 1월 10일, 생어는 누피디어 메일링 리스트를 통해 누피디아 프로젝트를 보완하기 위해 위키를 도입했다고 밝혔다.

위키백과는 2001년 1월 15일 서비스를 개시하였다. 도메인은 www.wikipedia.com을 사용하였고 사용 언어는 영어 하나뿐이었다. 래리 생어는 위키백과의 출범 소식 역시 누피디아 메일링 리스트를 통하여 알렸다. 위키백과가 시작한지 한 달 안에 중립성 정책이 수립되었다. 이후 몇 가지 정책이 수립되면서 위키백과는 누피디아와는 별개인 서비스가 되었다. 애초에 보미스는 위키백과를 영리 목적으로 운영하려고 하였다.

위키백과의 초기 편집자들은 누피디아, 슬래시닷, 그리고 웹 검색 엔진 을 통해 유입되었다. 2001년 8월 8일 위키백과의 문서수는 약 8,000개가 되었다. 2001년 말이 되자 위키백과는 18개 언어판으로 늘었고, 문서 수는 2만여 개까지 늘어났다. 위키백과를 서비스 하는 언어는 2002년 말에는 26개, 2003년 말에는 46개, 2004년 말에는 161개로 늘어났다. 누피디아는 위키백과와 병립하여 운영되다가 컨텐츠를 위키백과로 넘기고 2003년 서버를 다운시켜 마감하였다.

2002년 사용자 사이에서 위키백과의 광고 수주와 그에 따른 상업적 운용에 대한 우려가 커졌고, 이에 따라 스페인어 위키백과 사용자들은 위키백과 소스를 포크 하여 별도의 위키백과인 엔시클로페디아 리브레(Enciclopedia Libre Universal en Español)를 개설하였다. 이에 자극받은 지미 웨일스는 위키백과에 광고를 도입하지 않겠다고 선언하였고 도메인을 wikipedia.com에서 wikipedia.org로 변경하였다.

영어 위키백과의 증대 속도는 2007년 초 정점을 찍었고, 2009년 8월 3백만 문서를 넘겼다. 위키백과 전체의 문서수는 2006년 가장 빠르게 늘어 매일 약 1,800 개의 문서가 새로 생겨났다. 그 뒤로 문서 증가 속도는 둔화되어 2013년의 경우 연평균으로 보았을 때 매일 약 800개의 문서가 새로 생겨났다. 위키백과의 성장 둔화 원인에 대해 팰로앨토 연구소 는 프로젝트의 품질이 고급화되면서 변화에 대한 저항이 있다고 분석한 바 있다. 성장 둔화에 대한 다른 분석으로는 "낮은 가지에 달린 열매"처럼 주제나 가치가 분명하여 쉽게 만들 수 있는 문서는 이미 다 만들어졌기 때문이라는 설명이 있다.

2009년 11월 스페인 마드리드의 후안 카를로스 국왕 대학교의 연구자는 2009년 1분기 동안 영어 위키백과가 49,000여 명의 기여자를 잃었다는 분석을 내놓았다. 2008년의 같은 기간에 줄어든 기여자 수가 4,900여 명이었던 것에 비해 열 배나 더 많은 수치였다. 《 월스트리트 저널》은 까다로워진 편집 지침의 증가가 이러한 경향을 이끌었다고 보도하였다. 지미 웨일스는 이러한 연구가 잘못된 방법론에 의한 것이라며 분석 결과를 거부하였다. 2년 뒤인 2011년 지미 웨일스는 한 인터뷰에서 기여자 감소를 인정하였지만, 2010년 6월의 "최소 36,000 명의 편집자"에서 2011년 6월 당시의 35,800 명의 편집자 사이의 격차는 그리 크지 않다고 주장하면서 위키백과 편집자의 수는 "안정적이고 지속적"이라고 말하였다. 2013년 매사추세츠 공과대학교의 《 테크놀로지 리뷰》에 실린 〈위키백과의 하락〉( The Decline of Wikipedia)은 지미 웨일스의 이러한 주장을 반박하고 있다. 이 글의 분석에 따르면 위키백과는 2007년 이후 위키백과 문서를 업데이트하고 교정하던 자원 편집자 가운데 3분의 1을 잃었으며, 편집자의 상당수는 사소한 편집만을 하는 것으로 나타났다.《 디 애틀랜틱》 2012년 7월호는 관리자의 수 역시 줄어들었다고 보도하였다. 2013년 11월 25일 《 뉴욕 》의 캐서린 워드는 "여섯 번째로 많이 사용되는 웹사이트인 위키백과가 내부 비판에 휩싸였다"는 기사를 내보냈다.

2007년 1월 위키백과는 처음으로 가장 인기있는 웹사이트 리스트 Top10에 이름을 올렸다. 컴스코어는 위키백과의 연간 방문자를 4,290만 명으로 집계하며 9위로 올렸고, 《뉴욕타임즈》는 10로 올렸다. 애플은 11위로 집계하였다. 2006년도의 순위가 33위였던 것에 비하면 놀라운 부상이었다. 2015년 3월 위키백과는 5위를 기록하였다. 이 시기 순위는 알렉사 인터넷의 조사에 의한 것으로, 위키백과는 2014년 내내 매 월 8억 이상의 페이지 뷰 를 기록하였다.

2012년 1월 영어 위키백과는 미국 의회의 온라인 저작권 침해 금지 법안(SOPA)와 지적 재산권 보호 법안(PIPA)의 제정 시도에 맞어 SOPA와 PIPA 반대 시위 의 일환으로 24시간 블랙아웃 시위를 벌였다.

2014년 1월 20일 수보드 바르마(Subodh Varma)는 《이코노믹 타임즈》에 투고한 글을 통해 위키백과가 2012년 12월에서 2013년 12월 사이에 전체적으로 페이지 뷰가 10퍼센트에 달하는 2억 번 이상의 페이지뷰를 잃었다고 발표하였다. 주요 언어판에 따라 나누면 영어 위키백과의 페이지뷰 감소율은 12%, 독일어가 17%, 일본어는 9% 였다. 바르마는 "만일 위키백과 운영자들이 통계 집계에 오류가 있다고 주장한다면 지난해 도입된 구글의 지식 그래프 가 그 입을 다물게 할 것"이라고 덧붙였다. 뉴욕 대학교의 부교수 클레이 셔키는 지식 그래프가 다른 사이트들의 페이지뷰를 잠식하고 있는 것에 대해 "검색 페이지에서 당신의 질문에 대한 답을 바로 볼 수 있는데 굳이 그 사이트를 방문하겠는가?"라고 반문하였다.

2016년 12월 위키백과는 가장 인기있는 웹사이트 리스트에 5위로 기록되었다.

위키백과의 가장 큰 특징은 누구나 편집과 관리에 참여할 수 있다는 점이다. 인터넷을 통해 누구나 글을 고칠 수 있는 체계인 위키로 만들어져 있어 집단 지성 적 특성을 가진다. 개방성은 위키백과의 가장 큰 특징 가운데 하나로, 원칙적으로 사용자들은 누구든 거의 모든 문서를 새로 만들고 수정할 수 있다. 하지만 장기인증 사용자만 편집하고 수정할 수 있는 문서도 있다.

그러나 이러한 강점은 동시에 악의적인 문서의 훼손이나 부정확한 내용의 수록에 취약하다는 약점이 되기도 한다. 위키백과 커뮤니티 는 이러한 약점을 보완하기 위해 편집 규칙을 정하고 일부 문서에 대한 생성과 편집을 규제하고 있다. 2009년 이후 여러 언어마다 위키백과 편집에 대한 커뮤니티의 규제가 강화되었다. 영어 위키백과는 대중적 관심이 높은 문서에 대한 편집을 위해서는 로그인이 필요하도록 하였고, 독일어 위키백과는 모든 문서에 대해 로그인 된 사용자만이 편집할 수 있도록 하였다.

과도한 편집 규제는 위키백과 성장의 걸림돌이라는 지적이 있고, 위키백과 커뮤니티 내에서도 과감한 편집은 위키백과의 기본 원칙 가운데 하나로 새로운 사용자를 포용하기 위해서라도 지켜져야 한다는 의견들이 있다.

한편, 위키백과 커뮤니티 내에 존재하는 편향으로 인해 여성을 비롯한 다양한 집단에 대한 개방이 부족하다는 지적도 있다. 2014년 8월 게이머게이트 논쟁에서 영어 위키백과의 중재위원회 가 내린 5명의 여성주의 운동가 차단 결정은 위키백과의 개방성에 대한 많은 논란을 불러오기도 하였다.

위키백과의 문서들은 끊임없이 누군가에 의해 수정된다. 위키백과의 편집 시스템인 미디어위키는 다양한 방법으로 문서의 수정 사항을 사용자에게 알려주어 검토할 수 있도록 한다. 사용자는 문서의 역사를 확인하여 누가 언제 어떤 내용을 수정했는 지 확인할 수 있다. 만약 변경 내용이 악의적인 문서 훼손이라면 사용자는 이를 손쉽게 되돌릴 수 있다. 또한 사용자는 시스템이 제공하는 "최근 바뀜"과 "주시문서 목록" 등의 기능을 통해 문서의 변경 사항을 쉽게 파악할 수 있다. 이러한 기능들은 위키백과가 반달리즘 으로부터 문서 훼손을 보호할 수 있도록 돕는다.

위키백과는 시작과 함께 문서의 신뢰성에 대한 의문이 따라다녔다. 누군가 보다 전문가적인 입장에서 사용자의 편집을 검토하고 제한할 수 있어야 한다는 주장이 늘 있다. 위키백과의 공동창립자인 래리 생어는 결국 이 문제로 인해 위키백과를 떠나 전문가의 검토를 거치는 시티즌디움을 창립하였다. 위키백과 역시 몇 차례의 명백한 오류와 특정 집단의 의도적인 개입으로 완전한 개방 정책을 수정하지 않을 수 없었다. 오랫동안 《 USA 투데이》의 편집장을 역임했던 존 시겐설러가 존 F. 케네디 의 암살에 연루되었다는 거짓 정보가 위키백과에 올라온 사례는 오랫동안 위키백과 문서의 오류에 대한 사례로 거론되었고, 2016년 1월에는 스위스의 정보 기관 공무원이 수년에 걸쳐 약 5,500 건에 달하는 문서를 악의적으로 편집하였다가 아이피가 차단되는 일이 벌어지기도 하였다.

위키백과의 문서 품질은 사용자들의 지속적인 수정과 검토에 의해서 유지되고 향상된다. 2003년 안드레 시포릴리는 위키백과 컨텐츠의 유지는 파괴적 활동보다 창조적 활동량이 훨씬 많기 때문에 가능한 것이라는 분석을 내놓았다. 그러나, 교묘한 거짓 정보는 매우 오랫동안 검토되지 못하고 남아있기도 한다. 영어 위키백과에서는 2005년 1월 31일 등재된 연쇄 강간범 잭 로비쇼라는 문서가 완전히 허구의 인물을 서술한 것이라는 것을 2015년이 되어서야 발견한 일도 있었다. 이 문서는 2015년 9월 3일 삭제되었다.

위키백과의 컨텐츠는 사용자들의 자발적인 참여로 이루어지기 때문에 사용자간의 소통이 매우 중요하다. 이를 위해 위키백과는 사랑방 과 같은 커뮤니티 공간을 제공하고 있다. 또한 위키백과의 모든 문서에는 "토론" 탭이 있어서 사용자들 사이에 문서 개선을 위한 토론이 이루어지도록 하고 있다.

위키백과 사용자들은 위키컨퍼런스와 같은 오프라인 모임을 통해 관심사를 공유하기도 한다. 위키백과를 운영하고 있는 위키미디어 재단은 매년 세계적인 컨퍼런스인 위키마니아 행사를 갖고 있다. 2016년 위키마니아는 이탈리아의 에시노라리오에서 열렸다. 위키마니아에서는 위키백과뿐만 아니라 위키미디어 재단이 운영하고 있는 위키미디어 공용, 위키데이터, 위키책, 위키문헌, 위키낱말사전과 같은 여러 자매 프로젝트의 주요 관심사도 함께 논의된다. 위키미디어 재단은 이들 여러 프로젝트의 활성화를 위해 세계 각지의 지부나 사용자 모임을 지원하는 사업도 하고 있다. 대한민국에서는 한국위키미디어협회 가 자발적 사용자 모임으로 활동중이다. 한국위키미디어협회는 2016년 1월 15일 위키백과 15주년 기념행사를 가졌다.

위키백과 커뮤니티는 종종 컬트 문화적인 것으로 묘사되지만, 그것이 늘 부정적인 면을 부각하는 것은 아니다. 위키백과 사용자들은 훌륭한 활동에 대해 반스타 를 부여하여 서로의 동기 유발을 하기도 한다.

위키백과는 사용자의 익명성을 보장한다. 다중이 익명으로 참여한다고 하더라도 커뮤니티가 활력을 띄면 정보의 질은 꾸준히 향상된다. 위키백과의 이러한 작업 방식은 크라우드 소싱이라는 이름으로 다른 분야에서도 시도되고 있다. 그러나, 실제로 위키백과에 정보를 추가하는 사람들은 전체 사용자 가운데 극히 소수라는 연구가 있고, 로그인 하지 않은 사용자에 대해서는 위키백과 커뮤니티가 이등시민 취급을 한다는 비판도 있다. 다트머스 대학교 연구진은 이를 검증하기 위한 2007년 연구에서 "로그인 하지 않은 익명의 편집자나 기여 횟수가 적은 편집자의 활동 역시 로그인 사용자와 동등한 신뢰성을 보인다"고 밝혔다. 2009년 《 비지니스 인사이더 》의 편집인 헨리 블라젯은 위키백과 문서에 대한 표집 조사 결과 대다수의 문서가 "아웃사이더"에 의해 생성된 뒤 "인사이더"에 의해 완성된다고 분석하였다.

몇몇 언어의 위키백과 커뮤니티는 자체적으로 문서들을 엮어서 출판물을 제작하기도 하는데, 독일어 위키백과의 경우 독일어 위키백과의 문서를 모아 2004년에 CD로, 2005년, 2006년에는 DVD와 책 으로 제작하였다.

위키백과의 내용은 처음에는 GNU 자유 문서 사용 허가서 아래 배포되었으나 2009년 6월, 크리에이티브 커먼즈 저작자표시-동일조건변경허락 3.0 Unported 라이선스 로 변경되었다.

위키백과는 특별한 위계가 없는 사용자들의 집단 활동이라는 점에서 아나키즘의 요소를 갖는 민주주의 체계로 평가되기도 한다. 위키백과 내의 모든 문서는 직접 내용 편집에 참여한 사용자를 포함하여 어느 누구도 소유권을 주장할 수 없다. 위키백과의 이러한 규칙은 커뮤니티가 공동으로 소유하는 가치에 대한 사적 이익 추구를 억제함으로써 공유지의 비극 을 방지하고자 만들어졌다.

위키백과의 관리는 다섯 원칙의 정신과 이를 구현하기 위한 정책과 지침에 따라 이루어진다. 정책과 지침은 커뮤니티의 총의에 의해 수립되거나 수정된다. 총의의 개념은 2005년 찰스 메튜의 위키미디어 메일링 리스트 에서 설명된 바와 같이 단순한 만장일치가 아닌 현시점에서 커뮤니티가 내릴 수 있는 최선의 타협이다. 위키백과의 커뮤니티는 각각의 언어마다 독립되어 있기 때문에, 언어판마다 총의는 다를 수 있다. 위키백과 초창기 가장 큰 논란은 문서의 중립성 확보였고, 이에 따라 위키백과가 시작된지 한 달 만에 중립적 시각이 정책으로 지정되었다. 한국어 위키백과 역시 2004년 중립적 시각 정책을 도입하였다. 문서와 커뮤니티의 성장에 따라 지침이 필요한 다양한 사안이 발생하였기 때문에 위키백과의 정책과 지침 역시 이에 대응할 수 있도록 다양하게 늘어났다.

위키백과 사용자들 사이의 논쟁 또는 분쟁은 모두 위키백과 커뮤니티 안에서 해결된다. 사용자들 사이의 문제는 서로간의 토론을 통해 해결하는 것이 가장 바람직하지만, 문서의 훼손이나 악의적인 행위 등으로부터 선의의 편집 활동을 보호하기 위한 조치도 필요하다. 문서를 삭제하거나 악의적인 사용자를 차단하는 것과 같은 활동은 커뮤니티 안에서 충분히 신뢰할 수 있다고 평가받아 관리자로 선출 된 사용자가 실행한다. 한편 사용자 사이의 논쟁은 중재위원회 와 같은 기구를 통해 상호 조정을 이루기도 한다.

위키백과는 위키미디어 재단이 운영하는 위키미디어 프로젝트 가운데 하나이다. 위키미디어 프로젝트에는 위키백과 외에도 위키낱말사전, 위키책, 위키미디어 공용, 위키문헌, 위키인용집, 위키데이터 등이 있다. 모든 위키미디어 프로젝트는 자발적으로 참여하는 사용자들의 커뮤니티에 의해 운영되며 위키미디어 재단은 이들 프로젝트의 유지, 소프트웨어와 하드웨어의 관리, 사용자 커뮤니티에 대한 지원과 같은 일들을 담당한다.

위키미디어 재단은 미국 캘리포니아주 샌프란시스코 에 본부를 둔 비영리 기구로 위키백과를 비롯한 위키미디어 프로젝트의 유지를 위한 기금을 조성하고 호스팅하고 있다. 위키백과가 시작된 지 2년 후인 2003년 6월 20일 플로리다 주 법인으로 설립되었으며 2007년 본부를 샌프란시코로 이전하였다. 2013년 귀속분 국세청 신고서에 따르면 재단의 기금 수익은 3천9백7십만 달러이고 지출된 경비는 2천9백만 달러이다. 또한 총 자산은 3천7백2십만 달러로 이 가운데 부채는 230만 달러이다.

2014년 5월 위키미디어 재단은 초대 사무국장 슈 가드너가 퇴임하고 2대 사무국장으로 라일라 트레티코프를 지명하였다. 《월스트리트 저널》은 2014년 5월 1일자 보도를 통해 새로운 사무국장의 취임을 소개하면서 트레티코프의 "정보는 공기와 같이 자유를 좋아한다."는 말을 인용하였다. 2016년 6월 3대 사무국장으로 캐서린 마허 가 취임하였다. 마허는 위키미디어 프로젝트의 운영 방향에 대해 커뮤니티 내에서 상호 공감을 형성하는 것이 무엇보다 중요하다는 입장을 밝혔다.

위키백과의 운영 프로그램은 미디어위키이다. 오픈 소스로 배포되는 자유 소프트웨어인 미디어위키는 PHP 기반의 위키 소프트웨어로 MySQL 데이터베이스를 이용한다. 위키백과 초기에는 펄로 작성된 유스모드위키를 사용하였으나 2002년 1월에 마그누스 만스커가 개발한 PHP와 MySQL 기반의 위키가 도입되었고, 다시 2002년 7월 리 다니엘 크로커 가 개발한 미디어위키를 3세대 소프트웨어로 도입하였다. 미디어위키는 이후로도 여러차례 업데이트 되어 위키백과를 비롯한 여러 위키미디어 프로젝트를 운영하는 소프트웨어가 되었다.

위키백과는 낮 시간을 기준으로 1초에 25,000~60,000페이지 요청을 수신한다. 페이지 요청은 먼저 스퀴드 캐시 서버의 프론트엔드 계층으로 내보낸다. 스퀴드 캐시가 처리할 수 없는 요청은 리눅스 가상 서버 소프트웨어를 실행하고 있는 부하 제어 서버로 내보낸다. 즉, 데이터베이스로부터 렌더링한 페이지를 보여 주기 위해 아파치 웹 서버들 가운데 하나로 요청을 내보낸다는 뜻이다. 웹 서버는 요청한 페이지를 전달하여 모든 언어판의 위키백과에 대한 페이지 렌더링을 수행한다. 속도를 더 빠르게 하기 위해 렌더링 된 페이지는 만료될 때까지 분산 메모리 캐시에 캐시 처리되며 이로써 대부분의 동일한 페이지 접근을 위해 페이지 렌더링을 완전히 생략할 수 있다.

위키백과에서는 단순 반복적인 활동을 위해 봇 으로 불리는 프로그램이 운영된다. 봇은 자주 혼동되는 오탈자를 바로잡거나 자동으로 생성될 수 있는 반복적인 문구의 삽입과 같은 일을 담당한다. 봇 역시 위키백과 커뮤니티의 사용자들이 작성하여 운영하며 잘못된 사용을 막기 위해 별도의 등록 절차를 거친다.

2005년에 영국의 네이처 지는 브리태니커 백과사전과 위키백과의 42가지 난해한 과학 기사를 비교한 평가 리뷰를 발표하였다. 그 결과는 위키백과의 정확도 수준이 브리태니커 백과사전에 근접한다는 것이었다. 다만, 비평가들은 모든 범위의 기사에 대한 무작위 표본 추출을 하였거나, 사회과학 또는 논쟁적인 사회 문제에 중점을 둔 유사한 연구의 경우에서는 그렇게 긍정적인 결과가 나오지 못하였을 수도 있다고 여겼다. 또 2006년 기사에서 타임 지는 위키백과는 누구나 편집할 수 있는 개방 정책을 갖고 있으며, 이로써 위키백과가 세계에서 가장 큰 백과사전으로 만들어질 수 있도록 하고, 지미 웨일즈 의 비전을 실현한다고 밝혔다.

위키백과는 누구나 참여할 수 있기 때문에 편집자의 시각에 따라 누군가가 악의적인 의도등으로 잘못된 정보를 입력할 수 있고, 이에 따라 잘못된 정보가 퍼져나갈 수 있다는 문제점이 제기되어 왔다. 예를 들어 2005년 영어 위키백과에서는 존 시겐설러라는 미국의 전직 언론인이 존 F. 케네디 대통령의 암살에 관여했다는 잘못된 정보가 올려져 있었다는 점이 밝혀졌으며, 한 익명 사용자가 신바드라는 미국의 코미디언이 사망했다는 거짓 정보를 올려 인터넷 전반에 잘못된 소문이 퍼지기도 했다.

또한 위키백과는 미국 내의 보수주의자들로부터 자유주의적이라는 비판을 받아왔다. 이로 인해 컨서버피디아 가 2006년에 개설되었다.

미 연구팀에 의하면, 영어판 위키백과에 등록된 문서 중 회사 관련 내용의 약 60% 정도가 잘못된 사실을 담고 있다는 연구결과가 나왔다. 연구팀의 교수는 이를 특정 회사들이 이미지를 긍정적으로 만들기 위해 위키백과에 회사에 유리한 내용을 삽입하기 때문인 것으로 추정하고 있다.

위키백과 - 공식 웹사이트 (위키백과 초기 화면)

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위키백과 - 위키백과, 우리 모두의 백과사전

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위키백과(위키百科, IPA: [ɥikçibɛ̝k̚k͈wa̠], [ykçibɛ̝k̚k͈wa̠] ( )) 또는 위키피디아( 영어: Wikipedia, IPA: [ˌwɪkɪˈpiːdɪə] ( ))는 누구나 자유롭게 쓸 수 있는 다언어판 인터넷 백과사전이다.[2] 2001년 1월 15일 지미 웨일스와 래리 생어가 창립하였으며[3] , 대표적인 집단 지성의 사례로 평가받고 있다.[4] 위키백과는 자유 저작물을 보유하고 상업적인 광고가 없으며 주로 기부금을 통해 지원을 받는 비영리 단체인 위키미디어 재단에 의해 소유되고 지원을 받고 있다.

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https://m.dongascience.com/news.php?idx=52955

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[탄소중립 연속기고]이산화탄소 증가, 바다도 몸살 앓는다

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한승희 광주과학기술원(GIST) 지구환경공학부 교수 약 45억년 전에 탄생한 지구는 생물과 무생물의 상호작용을 통해 지금의 모습으로 변화해오면서 대기는 기온을 일정하게 유지하는데 중요한 역할을 담당했다.온실 기체의…

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

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20204김주엽

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Based on analysis from NOAA's Global Monitoring Lab, global average atmospheric carbon dioxide was 414.72 parts per million ("ppm" for short) in 2021, setting a new record high despite the continued economic drag from the COVID-19 pandemic. In fact, the jump of 2.58 ppm over 2021 amounts tied for 5th-highest annual increase in NOAA's 63-year record.

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 20th century, annual emissions from burning fossil fuels have increased every decade, from an average of 3 billion tons of carbon (11 billion tons of carbon dioxide) a year in the 1960s to 9.5 billion tons of carbon (35 billion tons of carbon dioxide) per year in the 2010s, according to the Global Carbon Update 2021.

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 processes can remove, the 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.

X. Lan, B. D. Hall, G. Dutton, J. Mühle, and J. W. Elkins. (2020). Atmospheric composition [in State of the Climate in 2018, Chapter 2: Global Climate]. Special Online Supplement to the Bulletin of the American Meteorological Society, Vol.101, No. 8, August, 2020.

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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Based on analysis from NOAA's Global Monitoring Lab, global average atmospheric carbon dioxide was 414.72 parts per million ("ppm" for short) in 2021, setting a new record high despite the continued economic drag from the COVID-19 pandemic. In fact, the jump of 2.58 ppm over 2021 amounts tied for 5th-highest annual increase in NOAA's 63-year record.

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https://www.carbonbrief.org/mapped-how-climate-change-affects-extreme-weather-around-the-world/

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ATTRIBUTION | August 4. 2022. 16:30

In the early 2000s, a new field of climate-science research emerged that began to explore the human fingerprint on extreme weather, such as floods, heatwaves, droughts and storms.

Known as "extreme event attribution", the field has gained momentum, not only in the science world, but also in the media and public imagination. These studies have the power to link the seemingly abstract concept of climate change with personal and tangible experiences of the weather.

Scientists have published more than 400 peer-reviewed studies looking at weather extremes around the world, from wildfires in the US and heatwaves in India and Pakistan to typhoons in Asia and record-breaking rainfall in the UK. The result is mounting evidence that human activity is raising the risk of some types of extreme weather, especially those linked to heat.

To track how the evidence on this fast-moving topic is stacking up, Carbon Brief has mapped - to the best of our knowledge - every extreme-weather attribution study published to date.

Carbon Brief's analysis reveals:

71% of the 504 extreme weather events and trends included in the map were found to be made more likely or more severe by human-caused climate change.

9% of events or trends were made less likely or less severe by climate change, meaning 80% of all events experienced some human impact. The remaining 20% of events and trends showed no discernible human influence or were inconclusive.

Of the 152 extreme heat events that have been assessed by scientists, 93% found that climate change made the event or trend more likely or more severe.

For the 126 rainfall or flooding events studied, 56% found human activity had made the event more likely or more severe. For the 81 drought events studied, it's 68%.

First published in July 2017, this article is the fifth annual update (see endnote) to incorporate new studies. The aim is that it serves as a tracker for the evolving field of "extreme event attribution".

Using the map

The map above shows 504 extreme weather events and trends across the globe for which scientists have carried out attribution studies. The different symbols show the type of extreme weather; for example, a heatwave, flood or drought. The colours indicate whether the attribution study found a link to human-caused climate change (red), no link (blue) or was inconclusive (grey).

How to use our map of attribution studies.

Use the plus and minus buttons in the top-left corner, or double click anywhere, to zoom in on any part of the world. Click on a symbol to reveal more information, including a quote from the original paper to summarise the findings and a link to the online version.

The filter on the left allows users to select a specific type of weather event to look at or, for example, only those found to be influenced by climate change.

The filter can also be used to highlight extreme events from a particular year. (Note: earlier versions of this map classified events by the year that the study or analysis was published.) To isolate studies that assess the changing trends of weather extremes, click the "trend" box in the filter.

The software used to make the map currently only works with a Web Mercator projection (as used by virtually all major online map providers). It is worth noting that this - like all map projections - offers a somewhat distorted view of the world.

It is important to note that the weather events scientists have studied so far are not randomly chosen. They can be high-profile events, such as Hurricane Harvey, or simply the events that occurred nearest to scientific research centres. (More on this below.)

The map includes three different types of studies. The circles and hexagons on the map indicate papers published in peer-reviewed journals. The different shapes refer to whether the study considers an individual extreme event (circles), such as a wildfire or storm, or whether it analyses longer-term trends in extreme weather (hexagons), such as the change in frequency of flooding or marine heatwaves over time.

The third shape - triangles - indicate rapid attribution studies. These are quickfire assessments of the climate change contribution to extreme weather events, published online shortly after an event concludes. (More on this below.)

Finally, it is worth noting that some of the icon locations are approximate - particularly for studies that cover large regions. For example, global studies can be found grouped together in the middle of the Atlantic Ocean.

Extreme weather types

The events and trends shown on the map are covered by 431 individual scientific papers or rapid studies. Where a single study covers multiple events or locations, these have been separated out into individual entries on the map.

Combining the evidence over the past 20 years, the literature is heavily dominated by studies of extreme heat (30%), rainfall or flooding (25%) and drought (16%). Together, these make up more than two-thirds of all published studies (71%). The full list is available in this Google sheet.

As the chart below shows, the number of extreme events studied has grown substantially over the past 10-15 years. Note that formal studies typically follow a year or so after the event itself as the writing and peer-review process for journal papers can take many months.

The majority of studies included here have been published in the annual "Explaining extreme events" special issues of the Bulletin of the American Meteorological Society ( BAMS). Each bumper volume typically contains around 15-30 peer-reviewed studies of events from the previous year. Other studies have been found through the Climate Signals database and online searches through journals. This update includes studies published up to the end of May 2022.

(Note: The map currently only includes studies published in English.)

Specific types of event can be displayed in the chart below by clicking on the category names at the top.

Number of attribution studies by extreme weather event type and year. Note: the total number of events dipped in 2017 because the Bulletin of the American Meteorological Society special report for that year was published in early 2018 rather than late 2017. Chart by Carbon Brief using Highcharts.

Most of the categories of extreme weather are self-explanatory, but "storms" and "oceans" require a bit of explanation.

For this latest iteration of the map, a new category of "compound" extreme events has also been added. This includes, for example, a 2021 study that found climate change had contributed to the "high likelihood" of combined dry and hot events in recent decades over most of China.

A man wades through a flooded road in Madagascar, after tropical cyclone Batsirai, Feb 2022. Credit: Xinhua / Alamy Stock Photo.

Such studies show that attribution studies are increasingly considering the impacts of extremes, rather than focusing purely on the weather event.

This shift towards impacts "is quite significant", says Prof Peter Stott, who leads the climate monitoring and attribution team at the Met Office Hadley Centre and has been a co-editor of the BAMS reports since they began in 2012. He tells Carbon Brief:

"Impacts are hard to do because you have to establish a significant link between the meteorology and the impact in question. As editors, we've been trying to encourage more studies on impacts because it's the impacts rather than the meteorology per se that tends to motivate these types of study - and if we only have the attribution on the meteorological event then we only have an indirect link to the relevant impact."

Attribution of climate impacts could even be used in the courts, one 2021 study explained. The authors wrote a Carbon Brief guest post explaining how attribution science can be "translated into legal causality". They wrote:

"Attribution can bridge the gap identified by judges between a general understanding that human-induced climate change has many negative impacts and providing concrete evidence of the role of climate change at a specific location for a specific extreme event that already has led or will lead to damages."

Human influence on extreme weather

Of the attribution studies included here, scientists found that human-caused climate change has altered the likelihood or severity of an extreme weather event in 80% of cases studied (71% made more severe or likely and 9% made less so).

In Carbon Brief's first edition of this analysis in 2017, 68% of events were found to have a human impact (with 63% made more severe or likely and 6% less so).

While these figures are not representative of all extreme weather events - attribution studies have only been conducted on a relatively small number - previous research has taken this broader view. For example, a 2015 study estimated the fraction of all globally occurring heat and heavy rainfall extremes that was attributable to warming. The authors found that around 75% of "moderate daily hot extremes over land" and 18% of "moderate daily precipitation extremes over land" were attributable to the observed temperature increase since pre-industrial times. These fractions are expected to increase with further warming, the authors noted.

Note that events are classified here as having an human impact if climate change is found to have influenced at least one aspect of that event. For example, a study of the 2011 East Africa drought found that climate change contributed to the failure of the "long rains" in early 2011, but that the lack of "short rains" in late 2010 was down to the climate phenomenon La Niña. This event is, thus, designated as having a human impact.

For the majority of events affected by climate change, the balance has shifted in the same direction. That is, rising temperatures made the event in question more severe or more likely to occur. These events are represented by the red in the chart below. Clicking on the red "slice" reveals that heatwaves account for 40% of such events, rainfall or flooding for 20%, and droughts for 15%. Return to the original chart, and do the same with the other slices to see the proportion of different weather types in each category.

Pie chart showing the proportion of extreme events/studies that were found to have been made more likely/severe by climate change (red segment), less likely/severe (orange), had no link identified (blue) and were inconclusive or lacked sufficient data (grey). Clicking on a segment reveals the makeup of different types of extremes within that category. Chart by Carbon Brief using Highcharts.

In 11% of extreme weather events and trends studied, scientists found no discernible influence from human activity. These are coloured blue in the map and the chart above. For a further 9%, the observational data or modelling techniques used in the study were insufficient to reach a reliable conclusion (shown as grey in the map and pie chart).

In 9% of studied weather events and trends, scientists found climate change had made the event less likely or less severe (pale orange in the chart above).

Interestingly, a 2020 study analysed the way links between climate change and the California drought were portrayed in US media. It finds that the links were "covered widely in both local and national news", but notes:

"However, legitimate differences in the methods underpinning the attribution studies performed by different researchers often resulted in a frame of scientific uncertainty or disagreement in the media coverage."

As the case of California's drought shows, it is often necessary to dig deeper to understand the full picture. The rest of this article looks at the evidence for the three most-studied types of extreme weather - heatwaves, heavy rain and floods, and droughts - as well as some of the main issues in event attribution, and where the field as a whole is heading.

Heatwaves

The attribution map includes studies of 152 extreme heat events, of which 142 (93%) have been made more likely or more severe because of climate change. No studies have found a heatwave that has been made less severe by climate change, while studies of two events (1%) identified no influence and a further eight (5%) were inconclusive.

A volunteer pours water on a pedestrian during a heatwave in southern Pakistan, May 2022. Credit: Xinhua / Alamy Stock Photo.

The studies on extreme heat that did not find a role for climate change were an analysis of the Russian heatwave in 2010 and a rapid attribution study of the all-time high temperatures recorded in Rajasthan, India in May 2016. For the latter, the authors suggested that "the lack of a detectable trend may be due to the masking effect of aerosols on global warming and increased use of irrigation".

A particularly well-studied region for heatwaves in the literature is Australia, which accounts for 10% of the heat-related events included here. And climate change was found to play a role in all but one of the 15 Australian heat events studied. It is worth noting for that one event, however, that although the study (pdf, p145) was inconclusive for the city of Melbourne in south-east Australia, the authors did detect a human influence on extreme heat up the coast in Adelaide.

This raises a few important points. First, finding that climate change contributed to an event is not the same as saying it "caused" that event. Attribution is about working out if the likelihood or magnitude of a particular event happening now is different from what it would be in a world that was not warming.

A useful analogy - as explained in the first BAMS report in 2012 - is of a baseball player who starts taking steroids. If the player begins hitting 20% more home runs than before, it would not be possible to say for sure whether a particular home run is because of the steroids or the player's spontaneous skill. But it is possible to say how the steroids have altered the likelihood that the player hits a home run, by comparing their current and historical performances. As the report put it:

"Given that steroids have resulted in a 20% increased chance that any particular swing of the player's bat results in a home run, you would be able to make an attribution statement that, all other things being equal, steroid use had increased the probability of that particular occurrence by 20%."

Another important point is that in cases where attribution science finds that climate change is making a given type of extreme weather more likely, it does not necessarily follow that the chance of experiencing that kind of weather gets incrementally higher each year. Natural variability means that there will still be ups and downs in the strength and frequency of extreme events.

Finally, there is usually a level of confidence attached to attribution results. So, while two studies might both find a role for human influence in a given weather event, the signal may be stronger for one than the other. For the purposes of this analysis, the attribution map does not distinguish between high- and low-confidence results, but users can click through to each study for more details.

Heavy rain and flooding

Of the 126 rainfall or flooding events included in the attribution map, 71 (56%) found human activity had made the event more likely or more severe - a far smaller proportion than for heat-related studies. Nineteen studies (15%) found that climate change had made the whole event less likely to occur. Of the remaining heavy rainfall events, studies of 24 (19%) found no evidence of a link to climate change, while 12 (10%) were inconclusive.

That there is a more divided set of results for extreme rainfall than for heatwaves could suggest several things. In some cases, limited data might make it difficult to detect a clear "signal" of climate change above the "noise" of weather considered normal for a particular region. In other cases, an inconclusive result could reflect the fact that rainfall or flooding events are inherently more complex than heatwaves, with many ways for natural variability to play a role. Human factors, such as land use and drainage, also play a part in whether heavy rain leads to flooding.

Volunteers help move sandbags to protect a home from rising flood waters near Ottawa Canada, during 2019 floods. Credit: Colin Clarke / Alamy Stock Photo.

Take the UK, for example. While one study found climate change had increased the risk of floods in England and Wales in Autumn 2000 by at least 20% (and even up to 90%), another found little influence on summer rainfall in 2012 (pdf, p36).

This raises another important point. When it comes to interpreting the results of event attribution studies, it matters what the question is. For example, a 2013 study asked whether recent wet summers in north-western Europe were a response to retreating Arctic sea ice (pdf, p32). The answer from the study was "no". But, as a foreword from that year's BAMs report explains:

"Given the numerous ways climate change could influence precipitation in this region, a 'no' result for the role of Arctic sea ice should not be interpreted as an absence of any role at all for climate change."

The paper notes that, in a chaotic weather system, the complex dynamics of the atmosphere mean the size and path of a storm or heavy rainfall event has a large element of chance. This can make it tricky to identify where climate change fits in, potentially underestimating its influence.

Therefore, rather than analysing the weather patterns that bring a storm to an area, the authors argue that scientists should be looking at how the impact of that storm has been boosted by temperature changes - known as "thermodynamic" effects. Higher temperatures mean warmer seas, higher sea levels and more moisture evaporating into the atmosphere. These are changes that scientists can be more confident in, the authors wrote, and so should be the focus for attribution studies - rather than looking at changes to circulation patterns in the atmosphere.

For example, the paper reexamines an earlier study (pdf, p15) that suggested climate change had reduced the chances of the five-day heavy rainfall event that hit north-east Colorado in September 2013. Trenberth and colleagues argue that while climate change might not have made the specific weather system that brought the rain more likely, it will have contributed to the sheer volume of moisture in the atmosphere.

Chart shows the number of studies for each type of extreme event that fall within each category of human influence: More severe/likely (red), less severe/likely (yellow), no influence (blue) and inconclusive (grey). Chart by Carbon Brief using Highcharts.

While attribution studies of heatwaves are generally more straightforward than storms - as they focus on thermodynamic influences - the type of question they are asking is still important. The Russian heatwave in 2010 is a good example of this. One study looking at the severity of the event did not find a role for climate change. Yet another one, which did find an influence, looked at the likelihood of the event.

This apparent contradiction is tackled by a third study that reconciles the other two. It explains that "the same event can be both mostly internally-generated [i.e. by natural variability] in terms of magnitude and mostly externally-driven [i.e. by human-caused climate change] in terms of occurrence probability".

Otto, who is lead author of the third study, tells Carbon Brief:

"The studies, thus, only appear to be contradictory, but are, in fact, complementary."

It is also important to stress that the absence of evidence for a link to climate change is not the same as evidence of absence. In other words, it does not necessarily mean there was no human influence, just that a particular analysis did not find one. This is why a single study should never be considered the final word on how climate change influences a given type of extreme weather.

Drought

Of the 81 drought events and trends considered here, climate change was found to have increased the severity or likelihood of 55 (68%). Of the remainder, the likelihood or severity was reduced for one event (1%), while no discernible link with human activity was found for 15 (19%) and 10 (12%) were inconclusive.

This mixed bag of results reflects the inherent complexity of droughts. And, again, the specific question matters. Conclusions about the role of climate change in a specific drought could depend on whether a study looks at temperature, rainfall or soil moisture, for example.

As the 2015 BAMS report explains:

"Drought continues to be an event type where the results require significant context, and easy answers often remain elusive because of the many meteorological, hydrological, and societal drivers that combine to cause drought."

(For more on the different ways that droughts can be categorised, see this Carbon Brief guest post from 2018.)

Geographical reach

While much has been achieved in the field of extreme event attribution in a short space of time, scientists are constantly looking for ways to tailor their work to suit the people who might use it.

One major goal since the early days of the field has been to expand extreme event attribution to cover a larger and more diverse geographical area.

Where in the world scientists can carry out attribution studies - and for what kind of events - will always be limited by the quality and availability of observed data and appropriate models. The attribution map highlights, for example, that there are relatively few studies of extreme weather in Africa and South America.

In another example, scientists hoping to analyse Super Typhoon Mangkhut - which hit the Philippines in September 2018 - were unable to in part because of "very poor quality" observed data in publicly available datasets and a lack of models.

At the moment, there is also a heavy leaning towards weather events that are local to the modelling groups, or that have a particular scientific interest. Otto explains:

"For example, scientists often do attribution studies because an event occurs on their doorstep. The UK, California and Boulder [in Colorado] are, therefore, studied much more than other parts of the world, but that does not necessarily make them places particularly impacted by climate change."

This means that while the studies carried out so far are indicative of the role climate change is playing in extreme weather around the world, they should not be considered representative of all types of extreme weather everywhere, says Otto. She tells Carbon Brief:

"[The studies so far] are part of a picture, but we don't know what's on the missing puzzle pieces. And, crucially, we don't know how many pieces are missing."

For example, Otto recently penned a Carbon Brief guest post on how the lack of monitoring of heatwaves in Africa means they are a "forgotten impact" of climate change.

Real-time extreme weather attribution

As well as expanding the science to cover different types of weather and more of the world, scientists are getting faster at turning the handle on extreme event attribution studies - sometimes crunching the numbers just days after an event has occurred.

The rapid studies included here are all produced by the World Weather Attribution (WWA) initiative, described earlier, or the UK Met Office.

An example of analysis performed by the latter includes their review of the UK's weather in 2020, which was published by Carbon Brief. This showed that climate change increased the likelihood of the UK's warm year by approximately a factor of 50.

While the WWA individual rapid assessments are not individually peer-reviewed, they are conducted using methods that have been through the peer-review process. As the 2014 BAMS report explains:

"Much like other routine analysis, such as an operational seasonal forecast, statements made about heat events using these methods do not necessarily need to go through the peer-reviewed literature to be considered credible."

By conducting the analysis in the immediate aftermath of a weather event, these rapid studies provide almost-real-time information on the influence of climate change, rather than having to wait many months for a formal study.

(In some cases, these rapid assessments are later published in peer-reviewed journals. In these instances, the formal study is included in the attribution map, rather than the initial analysis. In some cases, this means earlier rapid assessments are removed from the Carbon Brief map in order to add in the relevant peer-reviewed paper once it is published.)

The Trans Canada highway remains partially submerged by flood water after rainstorms lashed the western Canadian province of British Columbia in November 2021. Credit: Reuters / Alamy Stock Photo.

This collaboration between the UK Met Office, German weather service (DWD), Meteo France, Dutch weather service (KNMI) and the University of Oxford will "demonstrate how attribution of extreme weather events can be carried out operationally by national meteorological services", Prof Stott tells Carbon Brief:

"In this project we are developing and testing the protocols we will need to enable rapid and reliable assessments of the extent to which recent extreme weather events have been made more or less intense or more or less likely by climate change. We started at the beginning of the year and so far we have tested our procedures on an analysis of the 2018 heatwave in Europe."

The progress to date has "demonstrated the importance of international collaboration for developing new techniques and processes", says Stott. But "national meteorological services across Europe will continue to have a particular remit to deliver advice on weather and climate in their own countries", he adds:

"At the Met Office in the UK we are developing our operational attribution capability to help inform the public, policymakers and journalists about the extent to which damaging extreme weather events like the floods in Yorkshire [in 2019] have been affected by climate change."

An evolving science

As the science of extreme event attribution has matured and become more nuanced, so has the choice of terminology around extreme weather and climate change.

While some attest that all extreme weather must be affected by a world that is warming, this warrants some caution. As the first BAMS report in 2012 noted:

"While it has been argued that in the Anthropocene, all extreme weather or climate events that occur are altered by human influence on climate...this does not mean that climate change can be blamed for every extreme weather or climate event. After all, there has always been extreme weather."

But while it would be premature to suggest that any single study is the last word, it is clear that - in many cases - the science can do better than that. Similarly, scientific thinking has clearly moved on from the unsatisfactory statement that it is not possible to attribute any individual weather event to climate change. Indeed, as mentioned earlier, there have been some studies that have concluded that an event - or aspect of an event - would have been impossible without climate change.

Russian Federal Agency for Forestry works to put out a forest fire in Basly, Russia in August 2020. Credit: Reuters / Alamy Stock Photo.

Ultimately, there are no blanket rules in attribution. Scientists need to examine the circumstances of each individual weather event - or a longer pattern of events for trend studies. It is only by combining evidence from all around the world that they can begin to draw broader conclusions.

Attribution studies, therefore, rely heavily on the quality and availability of observational data and climate model simulations. In a short paper for the journal Weather, Dr Otto says that "the models used for attribution need to be able to reliably estimate the likelihoods of the types of events being attributed".

As discussed earlier, attribution studies of heatwaves tend to be more straightforward because of their focus on thermodynamic effects, rather than atmospheric circulation. Yet, Otto tells Carbon Brief that recent studies suggest models overestimate the year-to-year variability of heat extremes in some parts of the world, and thus underestimate the trend and the role of climate change.

In a rapid attribution study of the western Europe summer heatwave in 2019, for example, Otto and her colleagues found that, for the month of June, the models "show about 50% smaller trends than observations in this part of Europe and much higher year-to-year variability than the observations". Similarly, a study of the 2019-20 Australian bushfires noted that "models underestimate the observed trend in heat" and so the "real increase could be much higher".

These findings emphasise how important it is to analyse models and observations together, Otto says:

"This made me realise just how important attribution is for the scientific community - and everyone using climate science - at bringing observations and models together in a very concrete real-world test case.

Attribution can, therefore, be used to help scientists "identify where the models are doing well and for what they are not in a much more direct way than the classical skill assessment of climate projections does", adds Otto.

Forecasted attribution

One attempt to move attribution science forward was the very first "advance forecasted" attribution analysis, which quantified the impact of climate change on the size, rainfall, and intensity of Hurricane Florence before it made landfall in North Carolina in September 2018.

The analysis ran two sets of short-term forecasts for the hurricane: one as the climate is today and the other in a simulated world without human-caused climate change. The researchers concluded at the time:

"We find that rainfall will be significantly increased by over 50% in the heaviest precipitating parts of the storm. This increase is substantially larger than expected from thermodynamic considerations alone. We further find that the storm will remain at a high category on the Saffir-Simpson scale for a longer duration and that the storm is approximately 80km in diameter larger at landfall because of the human interference in the climate system."

The analysis received a mixed reaction. Prof Stott told Carbon Brief that it was "quite a cool idea", but would be dependent on being able to forecast such events reliably. Dr Kevin Trenberth, distinguished senior scientist at the National Center for Atmospheric Research, described it as "a bit of a disaster". He told Carbon Brief that the quality of the forecast was questionable for the assessment:

"The forecasts made were not good: the intensity of the forecast storm at landfall was category 4 or 5 as I recall, instead of category 2. And so the statements made were based on quite flawed assumptions: namely, that they had a good forecast."

A key requirement for a reliable attribution study is for models to accurately replicate the extreme event, Trenberth added, but "obviously one can not assess the goodness of the forecast if one does this in advance".

Houses in North Carolina sit in floodwater caused by Hurricane Florence. Credit: Reuters / Alamy Stock Photo.

The authors subsequently published a paper in Science Advances that "reviews the forecasted attribution with the benefit of hindsight". The findings show that climate change increased rainfall amounts "associated with the forecasted storm's core" by around 5%, and contributed to Hurricane Florence being "about 9km larger in mean maximum diameter (or a 1.6% increase in storm area) due to climate change".

The authors acknowledged that the "quantitative aspects of our forecasted attribution statements fall outside broad confidence intervals of our hindcasted statements and are quite different from the hindcasted best estimates". In short, the results are quite a way off what they forecasted.

However, the authors also said they have identified what went wrong with their forecasted analysis. Problems with the way their "without climate change" model runs were set up created a larger contrast against their real-world simulations. The results thus suggested that climate change would have a bigger impact than it actually did.

Nonetheless, the study did identify a quantifiable impact of climate change on Hurricane Florence, adding to the evidence from studies by other author groups, the researchers concluded:

"As the climate continues to warm, it is expected that extreme tropical cyclone precipitation events and resulting inland flooding will become yet more frequent."

In addition, a 2021 study of the record Australian heat event of October 2015 noted the potential of their methods "to provide attribution statements for forecast events within an outlook period". This will "allow for informed messaging to be available as required when an extreme event occurs, which is of particular use to weather and climate services", the authors wrote.

On the topic of forecasts, a 2021 study showed how it was possible to use a weather forecast model for attribution. The researchers, who penned a Carbon Brief guest post about their work, tested their methods using the European heatwave of February 2019 - an event their model successfully predicted:

"We find that the direct impact of the extra carbon dioxide (CO2) that humans have pumped into the atmosphere made the event 42% more likely for the British Isles and at least 100% (two times) more likely for France."

Their work "so far represents just the first few steps towards an operational forecast-based attribution system", they noted.

Finally, as well as casting forwards, attribution can also look back in time. A 2020 study on the US " Dust Bowl " heat and drought events of the 1930s takes an unconventional approach of looking at how the past event "would behave" with present-day levels of greenhouse gases.

The researchers find that "the return period of a 1-in-100-year heatwave summer (as observed in 1936) would be reduced to about 1-in-40 years" in today's climate.

Carbon Brief will continue to add new extreme event attribution studies to the map and update the accompanying analysis every year. Please get in touch with any suggestions of attribution studies that could be included.

This is the fifth iteration of Carbon Brief's attribution map. This is the fourth iteration of Carbon Brief's attribution map. The first, second and third and fourth editions, published in July 2017, March 2019 and April 2020, respectively, are still available at the archived links included here.

Original interactive map by Rosamund Pearce for Carbon Brief. Revised and updated by Tom Prater and Joe Goodman.

Please note: International borders are determined by the mapping software, not Carbon Brief.

Update: This article was updated on 05/08/2022 to include a mention of a 2015 attribution study of all global heat and heavy rainfall extremes.

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Mapped: How climate change affects extreme weather around the world

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In the early 2000s, a new field of climate science research emerged that began to explore the human fingerprint on extreme weather, such as floods, heatwaves, droughts and storms.

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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.

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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.

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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.

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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.climate.gov/news-features/understanding-climate/climate-change-global-temperature

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https://www.quantamagazine.org/how-earths-climate-changes-naturally-and-why-things-are-different-now-20200721/

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Faint Young Sun

Magnitude: No net temperature effect

Time frame: Constant

Though the sun's brightness fluctuates on shorter timescales, it brightens overall by 0.009% per million years, and it has brightened by 48% since the birth of the solar system 4.5 billion years ago.

Scientists reason that the faintness of the young sun should have meant that Earth remained frozen solid for the first half of its existence. But, paradoxically, geologists have found 3.4-billion-year-old rocks that formed in wave-agitated water. Earth's unexpectedly warm early climate is probably explained by some combination of less land erosion, clearer skies, a shorter day and a peculiar atmospheric composition before Earth had an oxygen-rich atmosphere.

Clement conditions in the second half of Earth's existence, despite a brightening sun, do not create a paradox: Earth's weathering thermostat counteracts the effects of the extra sunlight, stabilizing Earth's temperature (see next section).

Carbon Dioxide and the Weathering Thermostat

Magnitude: Counteracts other changes

Time frame: 100,000 years or longer

The main control knob for Earth's climate through deep time has been the level of carbon dioxide in the atmosphere, since carbon dioxide is a long-lasting greenhouse gas that blocks heat that tries to rise off the planet.

Volcanoes, metamorphic rocks and the oxidization of carbon in eroded sediments all emit carbon dioxide into the sky, while chemical reactions with silicate minerals remove carbon dioxide and bury it as limestone. The balance between these processes works as a thermostat, because when the climate warms, chemical reactions become more efficient at removing carbon dioxide, putting a brake on the warming. When the climate cools, reactions become less efficient, easing the cooling. Consequently, over the very long term, Earth's climate has remained relatively stable, providing a habitable environment. In particular, average carbon dioxide levels have declined steadily in response to solar brightening.

However, the weathering thermostat takes hundreds of thousands of years to react to changes in atmospheric carbon dioxide. Earth's oceans can act somewhat faster to absorb and remove excess carbon, but even that takes millennia and can be overwhelmed, leading to ocean acidification. Each year, the burning of fossil fuels emits about 100 times more carbon dioxide than volcanoes emit - too much too fast for oceans and weathering to neutralize it, which is why our climate is warming and our oceans are acidifying.

Plate Tectonics

Magnitude: Roughly 30 degrees Celsius over the past 500 million years

Time frame: Millions of years

The rearrangement of land masses on Earth's crust can slowly shift the weathering thermostat to a new setting.

The planet has generally been cooling for the last 50 million years or so, as plate tectonic collisions thrust up chemically reactive rock like basalt and volcanic ash in the warm, wet tropics, increasing the rate of reactions that draw carbon dioxide from the sky. Additionally, over the last 20 million years, the building of the Himalayas, Andes, Alps and other mountains has more than doubled erosion rates, boosting weathering. Another contributor to the cooling trend was the drifting apart of South America and Tasmania from Antarctica 35.7 million years ago, which initiated a new ocean current around Antarctica. This invigorated ocean circulation and carbon dioxide-consuming plankton; Antarctica's ice sheets subsequently grew substantially.

Earlier, in the Jurassic and Cretaceous periods, dinosaurs roamed Antarctica because enhanced volcanic activity, in the absence of those mountain chains, sustained carbon dioxide levels around 1,000 parts per million, compared to 415 ppm today. The average temperature of this ice-free world was 5 to 9 degrees Celsius warmer than now, and sea levels were around 250 feet higher.

Asteroid Impacts

Magnitude: Approximately 20 degrees Celsius of cooling followed by 5 degrees Celsius of warming (Chicxulub)

Time frame: Centuries of cooling, 100,000 years of warming (Chicxulub)

The Earth Impact Database recognizes 190 craters with confirmed impact on Earth so far. None had any discernable effect on Earth's climate except for the Chicxulub impact, which vaporized part of Mexico 66 million years ago, killing off the dinosaurs. Computer modeling suggests that Chicxulub blasted enough dust and sulfur into the upper atmosphere to dim sunlight and cool Earth by more than 20 degrees Celsius, while also acidifying the oceans. The planet took centuries to return to its pre-impact temperature, only to warm by a further 5 degrees Celsius, due to carbon dioxide in the atmosphere from vaporized Mexican limestone.

How or whether volcanic activity in India around the same time as the impact exacerbated the climate change and mass extinction remains controversial.

Evolutionary Changes

Magnitude: Depends on event; about 5 degrees Celsius cooling in late Ordovician (445 million years ago)

Time frame: Millions of years

Occasionally, the evolution of new kinds of life has reset Earth's thermostat. Photosynthetic cyanobacteria that arose some 3 billion years ago, for instance, began terraforming the planet by emitting oxygen. As they proliferated, oxygen eventually rose in the atmosphere 2.4 billion years ago, while methane and carbon dioxide levels plummeted. This plunged Earth into a series of "snowball" climates for 200 million years. The evolution of ocean life larger than microbes initiated another series of snowball climates 717 million years ago - in this case, it was because the organisms began raining detritus into the deep ocean, exporting carbon from the atmosphere into the abyss and ultimately burying it.

When the earliest land plants evolved about 230 million years later in the Ordovician period, they began forming the terrestrial biosphere, burying carbon on continents and extracting land nutrients that washed into the oceans, boosting life there, too. These changes probably triggered the ice age that began about 445 million years ago. Later, in the Devonian period, the evolution of trees further reduced carbon dioxide and temperatures, conspiring with mountain building to usher in the Paleozoic ice age.

Large Igneous Provinces

Magnitude: Around 3 to 9 degrees Celsius of warming

Time frame: Hundreds of thousands of years

Continent-scale floods of lava and underground magma called large igneous provinces have ushered in many of Earth's mass extinctions. These igneous events unleashed an arsenal of killers (including acid rain, acid fog, mercury poisoning and destruction of the ozone layer), while also warming the planet by dumping huge quantities of methane and carbon dioxide into the atmosphere more quickly than the weathering thermostat could handle.

In the end-Permian event 252 million years ago, which wiped out 81% of marine species, underground magma ignited Siberian coal, drove up atmospheric carbon dioxide to 8,000 parts per million and raised the temperature by between 5 and 9 degrees Celsius. The more minor Paleocene-Eocene Thermal Maximum event 56 million years ago cooked methane in North Atlantic oil deposits and funneled it into the sky, warming the planet by 5 degrees Celsius and acidifying the ocean; alligators and palms subsequently thrived on Arctic shores. Similar releases of fossil carbon deposits happened in the end-Triassic and the early Jurassic; global warming, ocean dead zones and ocean acidification resulted.

If any of that sounds familiar, it's because human activity is causing the same effects today.

As a team of researchers studying the end-Triassic event wrote in April in Nature Communications, "Our estimates suggest that the amount of CO ₂ that each ... magmatic pulse injected into the end-Triassic atmosphere is comparable to the amount of anthropogenic emissions projected for the 21st century."

Update: July 24, 2020
An earlier version of this article included a chart of carbon dioxide and oxygen concentrations through deep time. That chart was based on a single data source and does not reflect the best available modern evidence. It has been removed it from the article.

# data[].attributes.attachment_link.title
How Earth's Climate Changes Naturally (and Why Things Are Different Now)

# data[].attributes.attachment_link.description
Magnitude: No net temperature effect Time frame: Constant Though the sun's brightness fluctuates on shorter timescales, it brightens overall by 0.009% per million years, and it has brightened by 48% since the birth of the solar system 4.5 billion years ago.

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

# data[].attributes.body
https://www.scientificamerican.com/article/10-solutions-for-climate-change/

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

# data[].attributes.attachment_link.readable_text
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

# data[].attributes.attachment_link.description
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.

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

# data[].attributes.attachment_link.readable_text
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

# data[].attributes.attachment_link.description
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.

# data[].attributes.body
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.

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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://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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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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https://climate.nasa.gov/vital-signs/global-temperature/

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https://climate.nasa.gov/vital-signs/global-temperature/

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Climate Change: Vital Signs of the Planet

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Key Takeaway:

Earth's global average surface temperature in 2020 statistically tied with 2016 as the hottest year on record, continuing a long-term warming trend due to human activities.

This graph shows the change in global surface temperature compared to the long-term average from 1951 to 1980. The year 2020 statistically tied with 2016 for the hottest year on record since recordkeeping began in 1880 (source: NASA/GISS). NASA's analyses generally match independent analyses prepared by National Oceanic and Atmospheric Administration (NOAA) and other institutions.

The animation on the right shows the change in global surface temperatures. Dark blue shows areas cooler than average. Dark red shows areas warmer than average. Short-term variations are smoothed out using a 5-year running average to make trends more visible in this map.

The data shown are the latest available, updated annually.

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Global Surface Temperature | NASA Global Climate Change

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A graph and an animated time series showing the change in global surface temperature relative to 1951-1980 average temperatures. The year 2020 ties with 2016 as the warmest on record.

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https://www.scientificamerican.com/article/10-solutions-for-climate-change/

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https://www.scientificamerican.com/article/10-solutions-for-climate-change/

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https://www.scientificamerican.com/article/10-solutions-for-climate-change/

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Ten possibilities for staving off catastrophic climate change