Warming Predicted to Cause Drought

NASA
Lead author: Drew Shindell
Where published: Geophysical Research Letters

The researchers compared historical records of the climate impact of changes in the sun's output with model projections of how a warmer climate driven by greenhouse gases would change rainfall patterns. They found that a warmer future climate likely will produce droughts in the same areas as those observed in ancient times, but potentially with greater severity ... The same model showed that greenhouse-gas warming has similar effects on the atmosphere, suggesting drier conditions may become more common in the subtropics. Rainfall could decrease further in already water-stressed regions such as the southwest United States, Mexico, parts of North Africa, the Middle East, and Australia.
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IPCC 2007 Report

Intergovernmental Panel on Climate Change

Global atmospheric concentrations of carbon dioxide, methane and nitrous oxide have increased markedly as a result of human activities since 1750 and now far exceed pre-industrial values determined from ice cores spanning many thousands of years. The global increases in carbon dioxide concentration are due primarily to fossil fuel use and land-use change, while those of methane and nitrous oxide are primarily due to agriculture.
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The understanding of anthropogenic warming and cooling influences on climate has improved since the Third Assessment Report (TAR), leading to very high confidence that the globally averaged net effect of human activities since 1750 has been one of warming.
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