Potential effect of climate change on the distribution and range of arid regions.

To understand the potential effects of climate change on desertification,the impact of climate change on arid regions in China was analyzed using an aridity index and climate change scenarios A1,A2,B1 and B2.The simulated results showed that climate change in China will cause a decrease in the total area of hyper-arid and humid regions,but an increase in the total area of arid,semi-arid and semi-humid regions.The hyper-arid regions will be replaced by arid regions.The semi-arid regions will expand south and east from the semi-humid regions.The north-eastern and western parts of humid regions will be replaced by semi-arid or semi-humid regions. The semi-arid and semi-humid regions will expand west,north and south from the humid regions.The change in area of both hyper-arid and humid regions was negatively correlated with annual mean temperature in China,while the change in area of arid,semi-arid and semi-humid regions was positively correlated with annual mean temperature in China.Due to increasing annual mean precipitation,the total area of hyper-arid or arid regions will decrease, while that of humid or semi-arid regions will increase.The total area of semi-arid regions decreased with increased annual mean precipitation under all scenarios except A1.Due to increasing annual mean temperature,the total area of humid regions will decrease,while that of other climatic regions will increase.Climate change will cause increased desertification in China,while climatic drought stress will be weakened.