The summer warming of Beijing (China) under the Paris Agreement

Abstract

The shifting thermal environment brought by global warming presents new concerns for urban residents. However, the lack of urban presentation in the global and regional climate models limits the ability of these models to provide useful information at the urban scale. This study examines the impact of 1.5 °C and 2 °C global warming levels (GWL1.5 and GWL2) on the future summer of Beijing, China. A new statistical-dynamical downscaling (SDD) method was applied using available Coordinated Regional Climate Downscaling Experiment (CORDEX) ensemble data to downscale climate projections across Beijing at different GWLs. The results showed that the maximum air temperature increase reached 3.5 °C and 4 °C at GWL1.5 and GWL2, respectively, in the central urban area of Beijing. The historical urban heat island (UHI) intensity first increased to 2.48 ± 0.97/1.02 ± 0.58 °C in GWL1.5 and then decreased to 2.24 ± 0.98/0.90 ± 0.69 °C in GWL2 at 22:00/09:00. Under GWL1.5, the UHI effect is greater in the eastern metropolitan areas (> 2 °C) than in the western regions (0.5–1.5 °C). The highest daytime and nighttime UHIs occurred mostly in LCZ154 (open high-rise area). The intensity, duration, and frequency of future heat waves (HWs) are increasing, especially in urban areas under GWL2. Climate information on UHIs and HWs under the Paris Agreement would be very helpful for stakeholders and city planners to develop near-term future local adaptation policies.