Anthropogenic Influence on Seasonal Extreme Temperatures in Eastern China at Century Scale

Abstract

Given the scarcity of observational data in the early 20th century, very limited research has explored the impact of human activities on temperature extremes at the regional scale. Here we used a newly developed homogenized near-surface air temperature dataset since the beginning of the 20th century to estimate the frequency and intensity of extreme temperatures in eastern China and evaluate their anthropogenic influence based on models that participated into the Coupled Model Intercomparison Project phase 6 (CMIP6). We found clear increases in warm extremes and decreases in cold extremes since 1901 for both annual and seasonal mean temperatures, with more pronounced changes in the recent decades. The most significant warming was observed in spring and winter, approximately double the smallest warming observed in autumn. The CMIP6 models generally replicated the century-scale warming in annual and seasonal temperature extremes, depicting increases in the frequency and intensity of warm extremes and corresponding decreases in cold extremes. The optimal fingerprinting detections suggested that the century-scale warming can be clearly attributed to the influence of anthropogenic forcing, including seasonal extreme temperatures. The majority of observed changes in extreme temperatures can be attributed to anthropogenic greenhouse gas emissions, offset by a smaller, negative contribution from anthropogenic aerosol forcing, whereas natural forcing played a minor role. These results provide important information for accurately projecting future changes in temperature extremes.

Keywords: Extreme temperature, Century-scale changes, Anthropogenic forcing, Detection and attribution, Greenhouse gases, Anthropogenic aerosols