全球变化知识资源中心

Temperature-related health metrics are often determined not only by temperatures but also by multiple climate variables. Temperatures compounded by other climate variables are of significant concern in the assessment of climate change impacts on public health. Temperatures, wind speeds and their combined effects are investigated here for a comprehensive study of how measured temperatures, perceived temperature, and their related extremes will change in China under climate change conditions. Future projections of combined temperatures and wind speeds over China are generated through the PRECIS regional climate modeling system. Results indicate that temperatures can increase nearly 6 degrees C over China by the end of the twenty-first century from the baseline period (1976-2005) without considering the wind speed changes. However, by considering the combined effect of temperature and wind speed, the perceived temperatures over China are projected to decrease by 4.8 degrees C relative to the observed values in the baseline period. This unexpected drop in the future perceived temperatures suggests the projected warming is likely to be offset to a large extent by a potential increase in wind speed. This may be related to the RCM's high-resolution making the thermal contrast distribute at finer scales. The mechanism behind this result needs to be further investigated to help understand the related physical processes and the associated uncertainties at regional scales. As for low-temperature extremes, China is projected to experience an apparent decrease in the frequency and duration of extreme cold events in the future compared to the baseline period without considering the combined wind chill effect. Considering the wind chill effect, an opposite trend for extreme cold events is detected, with an increase by 21% in the frequency of temperatures below -20 degrees C.