Climate Change over China with a 2℃ Global Warming

Timing and climate change with a 2℃ global warming, with reference to the pre-industrial period, have been paid more attention to worldwide. In particular, many countries, including the member states of the European Union, and international organizations have set the greenhouse-gas emission targets for limiting global warming to 2℃. In this study, two sets of simulations performed with 16 atmospheric－ocean general circulation models, i.e., the model outputs from the 20th Century Climate in Coupled Models (20C3M) and from the Special Report on Emission Scenarios (SRES) emission scenarios B1, A1B, and A2, are used to analyze the timing, atmospheric concentration of greenhouse gases, and climate change over China with a 2℃ global warming. Based on the multi-model ensemble mean, a 2℃ global warming is expected to occur in 2064, 2046, and 2049, with equivalent atmospheric CO2 concentrations of 625 ppm, 645 ppm, and 669 ppm, under the SRES B1, A1B, and A2, respectively. At that time, warming is stronger overall in China. Where the spatial pattern is concerned, warming is stronger towards the north and on the Qinghai-Tibetan Plateau. At the national scale, annual mean surface air temperature is elevated by 2.7－2.9°C, and the winter temperature is elevated by 3.1－3.2℃, which is the strongest among the seasons. Annual mean precipitation is reduced by 0－5% in most parts of South China, but increased by 0－20% in the rest of the country. Annual (seasonal) mean precipitation is increased on average by 3.4%－4.4% (0.5%－6.6%) over China.