Geophys. Res. Lett. 34, L11706 (2007)

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The number of dangerously hot days in the Mediterranean is expected to increase by 200–500% during this century, if greenhouse-gas emissions continue to rise, according to new research. Led by Noah S. Diffenbaugh from Purdue's Climate Change Research Centre in Indiana, the study is the first detailed projection of future extreme temperatures in the climate-change hotspot.

Diffenbaugh and colleagues simulated climate change from 1961 to 1989 and 2071 to 2099 for 21 countries at an unprecedented spatial resolution of 20 kilometres. Extreme events, such as summer heat waves, will become much more common in this region in the future if CO2 emissions continue to rise, they found, with the greatest increase in extreme temperatures expected to occur in France and the Iberian Peninsula.

Coasts in the west and south of the Mediterranean will experience the greatest increase in days per year with dangerous heat and humidity, under both low and high fossil-fuel emission scenarios

But the researchers also show that lowering emissions to achieve atmospheric CO2 levels of 600 p.p.m.v. by the end of this century would curb the increase in extreme temperatures by up to 50%.