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For scientific and political disputes, see Global warming controversy, Scientific opinion on climate change and Public opinion on climate change.
For past climate change see Paleoclimatology and Geologic temperature record. For the Sonny Rollins album see Global Warming (album).
1880-2009 global mean surface temperature change relative to the 1961–1990 average. Source: NASA GISS
Comparison of ground based (blue) and satellite based (red: UAH; green: RSS) records of temperature variations since 1979. Trends plotted since January 1982.
Mean surface temperature change for the period ...view middle of the document...
An increase in global temperature will cause sea levels to rise and will change the amount and pattern of precipitation, probably including expansion of subtropical deserts. Warming is expected to be strongest in the Arctic and would be associated with continuing retreat of glaciers,permafrost and sea ice. Other likely effects include changes in the frequency and intensity ofextreme weather events, species extinctions, and changes in agricultural yields. Warming and related changes will vary from region to region around the globe, though the nature of these regional variations is uncertain. As a result of contemporary increases in atmospheric carbon dioxide, the oceans have become more acidic, a result that is predicted to continue.
The scientific consensus is that anthropogenic global warming is occurring.[B]Nevertheless, political and public debate continues. The Kyoto Protocol is aimed at stabilizing greenhouse gas concentration to prevent a "dangerous anthropogenic interference". As of November 2009, 187 states had signed and ratified the protocol.
Proposed responses to climate change include mitigation to reduce emissions, adaptation to the effects of global warming, and geoengineering to remove greenhouse gases from the atmosphere or block incoming sunlight.
Contents [hide] * 1 Temperature changes * 2 External forcings * 2.1 Greenhouse gases * 2.2 Aerosols and soot * 2.3 Solar variation * 3 Feedback * 4 Climate models * 5 Attributed and expected effects * 5.1 Natural systems * 5.2 Ecological systems * 5.3 Social systems * 6 Responses to global warming * 6.1 Mitigation * 6.2 Adaptation * 6.3 Geoengineering * 6.4 UNFCCC * 7 Views on global warming * 7.1 Politics * 7.2 Public opinion * 7.3 Other views * 8 Etymology * 9 See also * 10 Notes * 11 References * 12 Further reading * 13 External links |
Two millennia of mean surface temperatures according to different reconstructions, each smoothed on a decadal scale, with the actual recorded temperatures overlaid in black.
Evidence for warming of the climate system includes observed increases in global average air and ocean temperatures, widespread melting of snow and ice, and rising global average sea level. The most common measure of global warming is the trend in globally averaged temperature near the Earth's surface. Expressed as a linear trend, this temperature rose by 0.74 ± 0.18 °C over the period 1906–2005. The rate of warming over the last half of that period was almost double that for the period as a whole (0.13 ± 0.03 °C per decade, versus 0.07 °C ± 0.02 °C per decade). The urban heat island effect is estimated to account for about 0.002 °C of warming per decade since 1900. Temperatures in the lower troposphere have increased between 0.13 and 0.22 °C (0.22 and...