Anthropogenic emissions and land use/cover change contributions to extreme temperature changes over China

Extreme weather and climate events tend to increase and strengthen as global warming intensifies, which severely affect human life and sustainable economic development. Therefore, based on the Detection and Attribution Model Intercomparison Project (DAMIP) and the Land Use Model Intercomparison Project (LUMIP) provided by the Coupled Model Intercomparison Project phase 6 (CMIP6), the optimal fingerprinting method is applied to quantify the greenhouse gases (GHG), aerosols (AA), natural forcing (NAT), and land use/cover change (LUCC) contributions to the intensity, frequency, and duration of extreme temperatures in China during 1960-2020. The results show that GHG is the main driver of extreme temperature changes in China, except for ice days (ID0) and cold spells (CSDI). GHG causes an increase in warm spells (WSDI) by about 10 days and an extension of the growing season length (GSL) by 6 to 8 days. The Tibetan Plateau is the region with the strongest extreme temperature changes influenced by GHG. AA forcing has a cooling effect that partially offsets the warming effect of GHG, especially in southeastern China. It should be pointed out that AA forcing is also the main driver for the changes in diurnal temperature range (DTR) in southeastern China, which exceeds the GHG contribution. Additionally, LUCC has greater impact in nighttime extreme temperature indices changes than the regional AA, and becomes the second dominant factor beside GHG. LUCC leads to an attributable cooling contribution of 0.34 degrees C for the maximum of daily minimum temperatures (TNx). Spatially, the LUCC effects on extreme temperature changes are stronger in western China than in eastern China. The more robust estimation of the GHG, AA, NAT, and LUCC contributions over distinct regions provides an advanced understanding of anthropogenic impacts on regional extreme temperatures, which is expected to be an important reference for regional climate change adaptation and mitigation.

Automated summary

As global warming intensifies, extreme weather and climate events are increasing and strengthening, significantly impacting human life and sustainable economic development. Using the optimal fingerprinting method, this study quantifies the contributions of greenhouse gases (GHG), aerosols (AA), natural forcing (NAT), and land use/cover change (LUCC) to extreme temperature changes in China from 1960 to 2020. The results show that GHG is the main driver of extreme temperature changes in China, except for ice days and cold spells. AA forcing partially offsets the warming effect of GHG, especially in southeastern China. LUCC has a greater impact on nighttime extreme temperature indices changes than regional AA, becoming the second dominant factor alongside GHG. These findings provide valuable insights into anthropogenic impacts on regional extreme temperatures and can serve as important references for regional climate change adaptation and mitigation.