Effects of climate change on water resources in China

The average temperature in China has risen by 1.1 degrees C from 1908 to 2007. Temperatures increased from the 1920s to 1940s, followed by a decline in the 1950s to early 1980s. Temperatures went up again in the mid 1980s, with the 1990s being one of the warmest periods in China in the past 100 yr. Annual precipitation decreased gradually since the 1950s, with an average decline of 2.9 mm decade(-1), except for a slight increase from 1991 to 2000. Climate change has had undeniable effects on water resources in China. Over the past 50 yr, water distribution patterns have changed over China, especially in major river basins such as the Yangtze and Pearl River basins, where runoff has increased, while in other basins there was a decline. Based on 43 projection results of IPCC GG, GS, A2 and B2 scenarios, from 2000 on the annual mean air temperature in China will rise by 1.3 to 2.1 degrees C by 2020 and 2.3 to 3.3 degrees C by 2050. Annual mean precipitation in China will also increase in the next 50 yr, with a projected nationwide increase of 2 to 3% by 2020 and 5 to 7% by 2050. Runoff in main river basins will increase, except in some regions such as the Yellow and Hai River Basins. Northern parts of the country that are experiencing rapid socioeconomic development and population growth, however, will be faced with water shortages. To mitigate adverse effects caused by climate variability and changes in water resources, China has implemented strategies such as water saving, structural change in industry, rational water allocation and water transfer projects.