【中文介绍】

干旱是我国最为严重的自然灾害之一，每年均造成重大经济损失和生态环境破坏，甚至威胁人们身体健康和生命安全。本研究基于地球系统模式CESM的1.5^oC和2.0^oC平衡态试验结果，评估了相对工业革命前增温1.5^oC和2.0^oC时我国干旱人口暴露度变化问题。结果指出，当全球增温1.5^oC或2.0^oC时，我国干旱发生频次将显著增加，尤其是北方地区。相比增温1.5^oC，增温2.0^oC时我国干旱发生频次增加更为明显，0.5^oC的增温将导致我国干旱发生频次增加近9%，极端干旱发生频次增加了8%；对于西南地区，0.5^oC的增温将使得该区域极端干旱发生频次增加约21%。随着全球温度的增加，干旱所造成的影响也更加严重，0.5^oC的增温将导致我国极端干旱事件的人口暴露度也相对增加了近17%；西南地区极端干旱人口暴露度增加更为明显，大多数区域增加均超过了20%，即使未来人口数量在减少。因此，力争将本世纪末增温控制在1.5^oC以内是十分必要的，这将在很大程度上减弱了由于增温所带来的各种不利影响。

【英文介绍】

Drought, one of the major natural disasters in China, generally causes the largest socioeconomic loss each year and also has severe human health impacts. It is thus crucial to assess the changes in droughts in this region under different climate change scenarios. This study examines the impacts of stabilized 1.5 °C and 2.0 °C warming at the end of the 21st century on drought events in China by using a set of coupled Earth system model low-warming simulations. If warming is limited to 1.5 ° C or 2.0 °C, these simulations suggest that droughts will become more frequent and more intense compared to the present day, particularly over the northern regions of China. In comparison to the 1.5 °C warmer future, the 0.5 °C additional warming in the 2.0 °C warmer future will account for approximately 9% of the increase in the drought occurrence in China and approximately8%of extreme droughts, while there are relatively small responses for moderate and severe droughts. Consequently, the additional warming would lead to significantly higher drought impacts, and the population exposure to the extreme droughts is projected to increase by approximately 17%, although the exposure to moderate droughts decreases. Therefore, our results suggest that the mitigation of anthropogenic warming by 0.5 °C to achieve the 1.5 °C warmer climate instead of the 2.0 °C climate may have benefits for future drought risks and impacts.

图. 我国干旱的人口暴露度分布。（a）当前气候，（b）增温1.5^oC，（c）增温2.0^oC，（d）不同等级干旱人口暴露度的变化。单位：百万.

Figure. Spatial patterns of the population exposure (in thousands) to droughts in (a) present day, (b) 1.5 °C, and (c) 2.0 °C warmer climates. (d) Regional aggregated population exposure to different droughts in China (units: million).

Chen, H. P., and J. Q. Sun, 2019: Increased population exposure to extreme droughts in China due to 0.5^oC of additional warming. Environmental Research Letters, 14(064011), doi: 10.1088/1748-9326/ab072e.

【论文链接】

https://iopscience.iop.org/article/10.1088/1748-9326/ab072e