CALENTAMNIENTO

Global warming

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This article is about the current change in Earth's climate. For general discussion of how the climate can change, see Climate change. For other uses, see Global warming (disambiguation).

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Global mean land-ocean temperature change from 1880–2012, relative to the 1951–1980 mean. The black line is the annual mean and the red line is the 5-year running mean. The green bars show uncertainty estimates. Source: NASA GISS. (click for larger image)

Map of temperature changes across the world

key to above map of temperature changes

The map shows the 10-year average (2000–2009) global mean temperature anomaly relative to the 1951–1980 mean. The largest temperature increases are in the Arctic and the Antarctic Peninsula. Source: NASA Earth Observatory[1]

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Fossil fuel related CO2 emissions compared to five of the IPCC's "SRES" emissions scenarios. The dips are related to global recessions. Image source: Skeptical Science.

Global warming is the rise in the average temperature of Earth's atmosphere and oceans since the late 19th century and its projected continuation. Since the early 20th century, Earth's mean surface temperature has increased by about 0.8 °C (1.4 °F), with about two-thirds of the increase occurring since 1980.[2] Warming of the climate system is unequivocal, and scientists are 95-100% certain that it is primarily caused by increasing concentrations of greenhouse gases produced by human activities such as the burning of fossil fuels and deforestation.[3][4] These findings are recognized by the national science academies of all major industrialized nations.[5][A]

Climate model projections were summarized in the 2007 Fourth Assessment Report (AR4) by the Intergovernmental Panel on Climate Change (IPCC). They indicated that during the 21st century the global surface temperature is likely to rise a further 1.1 to 2.9 °C (2 to 5.2 °F change) for their lowest emissions scenario and 2.4 to 6.4 °C (4.3 to 11.5 °F change) for their highest.[6] The ranges of these estimates arise from the use of models with differing sensitivity to greenhouse gas concentrations.[7][8]

Future climate change and associated impacts[9] will vary from region to region around the globe.[10] The effects of an increase in global temperature include a rise in sea levels and a change in the amount and pattern of precipitation, as well as a probable expansion of subtropical deserts.[11] Warming is expected to be strongest in the Arctic, with the continuing retreat of glaciers,

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