global warning by

al_94253 — 2017-03-25 16:42:14 UTC

al_94253 — 2017-03-25 16:48:16 UTC

Future climate change and associated impacts will differ from region to region around the globe.^[12]^[13] Anticipated effects include warming global temperature, rising sea levels, changing precipitation, and expansion of deserts in the subtropics.^[14] Warming is expected to be greater over land than over the oceans and greatest in the Arctic, with the continuing retreat of glaciers, permafrost and sea ice. Other likely changes include more frequent extreme weather events including heat waves, droughts, heavy rainfall with floods and heavy snowfall;^[15] ocean acidification; and species extinctions due to shifting temperature regimes. Effects significant to humans include the threat to food security from decreasing crop yields and the abandonment of populated areas due to rising sea levels.^[16]^[17] Because the climate system has a large "inertia" and greenhouse gases will stay in the atmosphere for a long time, many of these effects will not only exist for decades or centuries, but will persist for tens of thousands of years.^[18]

al_94253 — 2017-03-25 16:49:29 UTC

al_94253 — 2017-03-25 16:50:31 UTC

The global average (land and ocean) surface temperature shows a warming of 0.85 [0.65 to 1.06] °C in the period 1880 to 2012, based on multiple independently produced datasets.^[26] Earth's average surface temperature rose by 0.74±0.18 °C over the period 1906–2005. The rate of warming almost doubled for the last half of that period (0.13±0.03 °C per decade, versus 0.07±0.02 °C per decade).^[27] Although the increase of near-surface atmospheric temperature is the measure of global warming often reported in the popular press, most of the additional energy stored in the climate system since 1970 has gone into the oceans. The rest has melted ice and warmed the continents and atmosphere.^[28]^[c]

al_94253 — 2017-03-25 16:53:21 UTC

Global warming is the process of increasing the average temperature of the Earth's oceans and atmosphere caused by mass greenhouse gas emissions from a range of human activities, especially fossil fuels and land use changes, Like deforestation, as well as other secondary sources. These causes are a direct product of the population explosion, economic growth, the use of polluting technologies and energy sources, and an unsustainable lifestyle where nature is seen as a raw material for exploitation. The major greenhouse gases emitted by man are carbon dioxide (or carbon dioxide, CO2) and methane (CH4). These and other gases act by obstructing a dissipation of terrestrial heat into space. The rise in temperature has been occurring since the mid-nineteenth century and now continues as emissions continue to rise.

al_94253 — 2017-03-25 16:56:28 UTC

al_94253 — 2017-03-25 17:02:13 UTC

he earth’s ocean temperatures are getting warmer, too—which means that tropical storms can pick up more energy. So global warming could turn, say, a category 3 storm into a more dangerous category 4 storm. In fact, scientists have found that the frequency of North Atlantic hurricanes has increased since the early 1980s, as well as the number of storms that reach categories 4 and 5. In 2005, Hurricane Katrina—the costliest hurricane in U.S. history—struck New Orleans; the second-costliest, Hurricane Sandy, hit the East Coast in 2012.

al_94253 — 2017-03-25 17:06:26 UTC

Each year, scientists learn more about the consequences of global warming, and many agree that environmental, economic, and health consequences are likely to occur if current trends continue. Here’s just a smattering of what we can look forward to:

Melting glaciers, early snowmelt, and severe droughts will cause more dramatic water shortages and increase the risk of wildfires in the American West.
Rising sea levels will lead to coastal flooding on the Eastern Seaboard, especially in Florida, and in other areas such as the Gulf of Mexico.
Forests, farms, and cities will face troublesome new pests, heat waves, heavy downpours, and increased flooding. All those factors will damage or destroy agriculture and fisheries.
Disruption of habitats such as coral reefs and Alpine meadows could drive many plant and animal species to extinction.
Allergies, asthma, and infectious disease outbreaks will become more common due to increased growth of pollen-producing ragweed, higher levels of air pollution, and the spread of conditions favorable to pathogens and mosquitoes.

al_94253 — 2017-03-25 17:23:40 UTC

Since 1978, solar irradiance has been measured by satellites.^[103] These measurements indicate that the Sun's radiative output has not increased during that time, so the warming during the past 40 years cannot be attributed to an increase in solar energy reaching the Earth.

Climate models have been used to examine the role of the Sun in recent climate change.^[104] Models are unable to reproduce the rapid warming observed in recent decades when they only take into account variations in solar output and volcanic activity. Models are, however, able to simulate the observed 20th century changes in temperature when they include all of the most important external forcings, including human influences and natural forcings.

Another line of evidence is differing temperature changes at different levels in the Earth's atmosphere.^[105] Basic physical principles require that the greenhouse effect produces warming of the lower atmosphere (the troposphere) but cooling of the upper atmosphere (the stratosphere).^[106]^[107]Depletion of the ozone layer by chemical refrigerants has also resulted in a strong cooling effect in the stratosphere. If solar variations were responsible for observed warming, warming of both the troposphere and stratosphere would be expected.^[108]

al_94253 — 2017-03-25 17:25:37 UTC

al_94253 — 2017-03-25 17:26:38 UTC

al_94253 — 2017-03-30 22:09:26 UTC

By greenhouse effect is meant a retention of heat by the atmosphere, preventing it from dissipating in space. The primary source of this heat is the Sun, which continually emits huge amounts of radiation into space at various wavelengths, including visible light and thermal radiation (heat), but also unobservable lengths for a human being without the aid of Instruments, like the ultraviolet. About a third of the radiation that Earth from the sun is reflected in the atmosphere back into space, but two-thirds of it comes to the surface, being absorbed by the continents and doing what you want. [17] On the other hand, the Commission considers that, with regard to living conditions.

al_94253 — 2017-03-30 22:16:08 UTC

al_94253 — 2017-03-30 22:18:51 UTC

Not all gases present in the atmosphere produce the greenhouse effect. Nitrogen and oxygen, which are largely preponderant, corresponding to 78% and 21% of dry air, have practically no action in this mechanism. It is due to the action of others, much less common and of more complex molecules, that nevertheless produce reactions in large scale.

al_94253 — 2017-03-30 22:20:32 UTC

There are multiple consequences of the intensification of the greenhouse effect on life on Earth and for man and his society, and in their vast majority, negative, with large-scale biological, social, cultural and economic repercussions. The species that flourish today in the world depend on reasonably stable climatic conditions to survive. The rapidity with which the recent rise in the world average temperature has been taking place prevents the species from adapting in time, necessarily generating a negative impact on the ecological balance, disrupting the food chains, interfering with the chemical and energy balance of living communities, causing their geographical redistribution , Favoring the proliferation of invasive species and many other forms, causing numerous species to suffer a pronounced population decline or even to extinction. These interferences can be serious enough to cause the irreversible collapse of whole ecosystems, as has already been observed in several cases. [20] [21] [22] [23] Projections by the International Union for the Conservation of Nature and Natural Resources indicate that global warming above 3.5 ° C will cause widespread impoverishment in terrestrial biodiversity, with a probable extinction of up to 70% of all known species. The IPCC has indicated that this is a real possibility, foreseen in some of the models used, although the more consensual projections point to a rise of just over 2 ° C by the year 2100. Even so, this rise should cause great effects Throughout the planet. [4]

al_94253 — 2017-03-30 22:23:08 UTC

al_94253 — 2017-03-30 23:13:04 UTC

al_94253 — 2017-03-30 23:38:37 UTC