Global warming refers to the increase in average temperature of the oceans and the air near the Earth's surface that has been experienced in recent decades, and the possibility of continuing it during the current century.
If this increase is due to natural causes or anthropogenic (man-made) is still the subject of some debate among scientists, although many meteorology and climatology have recently said publicly that they consider evidence that human action is actually influencing the occurrence of the phenomenon. The Intergovernmental Panel on Climate Change (IPCC) established by the United Nations and World Meteorological Organization in 1988, in its most recent report [1] says that much of the warming observed over the past 50 years has most likely been due to an increase in greenhouse effect caused by rising concentrations of greenhouse gases of anthropogenic origin (including, in addition to the increase of greenhouse gases, other changes such as those due to greater use of groundwater and soil for agriculture and an industrial increased energy consumption and pollution). The scientific consensus is that global warming is anthropogenic. Most academies of sciences of the world made a joint so that there was no consensus about the doubts.
The effects of external agents on the climate are complicated by several processes cyclical and self-powered, called Feedbacks. One of the most pronounced of these processes is related to the evaporation of water. The injected CO2 in the atmosphere causes the heating of it and the Earth's surface. The warming leads to more evaporation of water, and as the water vapor is a greenhouse gas, this leads to more warming, which in turn causes more evaporation of water, and so on, until it reached a new balance dynamic, with increased humidity and the concentration of water vapor, leading to an increase in greenhouse effect much greater than that due only to increase the concentration of CO2. This effect can only be reversed very slowly, since the CO2 has an average time of life a lot longo.Um feedback in the atmosphere still subject to research and debate is caused by clouds. Viewed from below, the clouds emit infrared radiation back to the surface, warming the same . Viewed from above, they reflect the sunlight and emit infrared radiation into space, cool the planet. The overall increase in concentration of water vapor may or may not cause an increase in average global coverage of clouds. Therefore, the effective role of clouds is not yet well defined, but its effects are less relevant that the only water vapor, and in models of the IPCC, they contribute to the heating <. Another important feedback is the relationship ice-albedo . The increased rate of CO2 in the atmosphere increases the temperature of the Earth and leads to melting of ice near the poles. With the melting of ice, land or sea open occupy its place. Both are, on average, substrates with lower capacity to think the ice, and thus absorb more solar radiation. This causes even more warming, causing more melting of ice, and the cycle continues. The positive feedback (pro-warming) due to the release of CO2, CH4 with the melting of permafrost is another mechanism that contributes to warming. Furthermore, the release of methane due to unfreeze funds for ocean is more a mechanism to be considered. The ability of oceanic absorption of carbon decreases with the heating, because the low levels of nutrients in the mesopelágica limit the growth of algae, encouraging the development of species phytoplanktonic minors, who are not as good absorbent carbon.
Consequences:
Because of the potential effects on human health, economy and environment global warming has been a source of great concern. Major environmental changes have been observed and were linked to global warming. Examples of secondary evidence cited below (reduction in ice cover, sea level rise, changes in weather patterns) are examples of the consequences of global warming that may influence not only the human activities but also ecosystems. Increased global temperature change allows an ecosystem, some species may be forced out of their habitats (possibility of extinction) due to changes in condition while others can spread, invading other ecosystems.
Because of the potential effects on human health, economy and environment global warming has been a source of great concern. Major environmental changes have been observed and were linked to global warming. Examples of secondary evidence cited below (reduction in ice cover, sea level rise, changes in weather patterns) are examples of the consequences of global warming that may influence not only the human activities but also ecosystems. Increased global temperature change allows an ecosystem, some species may be forced out of their habitats (possibility of extinction) due to changes in condition while others can spread, invading other ecosystems.
Because of the potential effects on human health, economy and environment global warming has been a source of great concern. Major environmental changes have been observed and were linked to global warming. Examples of secondary evidence cited below (reduction in ice cover, sea level rise, changes in weather patterns) are examples of the consequences of global warming that may influence not only the human activities but also ecosystems. Increased global temperature change allows an ecosystem, some species may be forced out of their habitats (possibility of extinction) due to changes in condition while others can spread, invading other ecosystems.
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