Drought and climate-change

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Drought in California

Droughts in Syria and California linked to climate change

by Debora MacKenzie

Syria and California have both recently suffered their worst-ever droughts, exacerbated by global warming. Syria’s may have helped trigger its bloody civil war, but not California’s, which instead brought vermin invasions and wildfire. The difference points to the resilience that will be needed in a warming world.

Colin Kelley of the University of California, Santa Barbara, and his colleagues analysed Syrian weather data since 1931, and found steadily less winter rainfall, which is crucial for crops, and higher temperatures, which dry soils faster. The only explanation for such a change over that timescale lies in man-made greenhouse emissions, says Kelley. Climate models, his team found, consistently predict such changes for the Fertile Crescent, the Middle Eastern area that includes Syria and Iraq.

The researchers used a statistical technique to separate the long-term drying that appeared linked to climbing CO2 emissions, from yearly, natural ups and downs in precipitation. Those natural variations led to the occasional drought by themselves, says Kelley. But, he adds, “the long-term drying trends exacerbated the recent drought, making it the most severe in the observed record.” Crops failed from 2006 to 2009 in Syria’s northeastern region that is its breadbasket – then when rains returned, they triggered an explosion of yellow rust, a wheat fungus, that killed up to half the crop.

Read the full article: New Scientist

Author: Willem Van Cotthem

Honorary Professor of Botany, University of Ghent (Belgium). Scientific Consultant for Desertification and Sustainable Development.

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