Sensitivity of Climate Changes to CO2Emissions in China

Abstract

In this study, the authors demonstrate that the Coupled Model Intercomparison Project Phase 5(CMIP5) models project a robust response in changes of mean and climate extremes to warming in China. Under a scenario of a 1% CO2 increase per year, surface temperature in China is projected to increase more rapidly than the global average, and the model ensemble projects more precipitation(2.2%/°C). Responses in changes of climate extremes are generally much stronger than that of climate means. The majority of models project a consistent response, with more warm events but fewer cold events in China due to CO2 warming. For example, the ensemble mean indicates a high positive sensitivity for increasing summer days(12.4%/°C) and tropical nights(26.0%/°C), but a negative sensitivity for decreasing frost days(-4.7%/°C) and ice days(-7.0%/°C). Further analyses indicate that precipitation in China is likely to become more extreme, featuring a high positive sensitivity. The sensitivity is high(2.4%/°C) for heavy precipitation days( 10 mm d-1) and increases dramatically(5.3%/°C) for very heavy precipitation days( 20 mm d-1), as well as for precipitation amounts on very wet days(10.8%/°C) and extremely wet days(22.0%/°C). Thus, it is concluded that the more extreme precipitation events generally show higher sensitivity to CO2 warming. Additionally, southern China is projected to experience an increased risk of drought and flood occurrence, while an increased risk of flood but a decreased risk of drought is likely in other regions of China.