Fan Xingwang, Zhang Yunlin, Shi Kun, Peng Jian, Liu Yongwei, Zhou Yongqiang, Liu Yuanbo, Zhu Qing, Song Chunqiao, Wan Rongrong, Zhao Xiaosong, Woolway R Iestyn
Key Laboratory of Lake and Watershed Science for Water Security, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 211135, China.
Key Laboratory of Watershed Geographic Sciences, Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 211135, China.
Proc Natl Acad Sci U S A. 2024 Oct 15;121(42):e2410294121. doi: 10.1073/pnas.2410294121. Epub 2024 Oct 7.
Compound drought-heatwaves (CDHWs) accelerate the warming and drying of soils, triggering soil compound drought-heatwaves (SCDHWs) that jeopardize the health of soil ecosystems. Nevertheless, the behavior of these events worldwide and their responses to climatic warming are underexplored. Here, we show a global escalation in the frequency, duration, peak intensity, and severity of SCDHWs, as well as an increase in affected land area, from 1980 to 2023. The increasing trends, which are particularly prominent since the early 2000 s, and projected to persist throughout this century, are dominated by summertime SCDHWs and enhanced by El Niño. Intensive soil warming as well as climatologically lower soil temperatures compared to air temperatures lead to localized hotspots of escalating SCDHW severity in northern high latitudes, while prolonged duration causes such hotspots in northern South America. Transformation of natural ecosystems, particularly forests and wetlands, to cropland as well as forest degradation substantially enhance the strength of SCDHWs. Global SCDHWs consistently exhibit higher frequencies, longer durations, greater severities, and faster growth rates than CDHWs in all aspects from 1980 to 2023. They are undergoing a critical transition, with droughts replacing heatwaves as the primary constraint. We emphasize the significant intensification of SCDHWs in northern high latitudes as well as the prolonged duration of SCDHWs in the Southern Hemisphere, posing an underrated threat to achieving carbon neutrality and food security goals.
复合型干旱热浪（CDHWs）加速了土壤的变暖和干燥，引发了危及土壤生态系统健康的土壤复合型干旱热浪（SCDHWs）。然而，这些事件在全球范围内的表现及其对气候变暖的响应尚未得到充分研究。在此，我们展示了1980年至2023年期间全球范围内SCDHWs在频率、持续时间、峰值强度和严重程度方面的升级，以及受影响土地面积的增加。自21世纪初以来尤为显著且预计将持续整个世纪的增长趋势，主要由夏季SCDHWs主导，并受厄尔尼诺现象增强。与气温相比，强烈的土壤升温以及气候学上较低的土壤温度导致北半球高纬度地区SCDHW严重程度不断升级的局部热点，而持续时间延长则在南美洲北部造成此类热点。自然生态系统，特别是森林和湿地向农田的转变以及森林退化，极大地增强了SCDHWs的强度。从1980年到2023年，全球SCDHWs在各个方面始终表现出比CDHWs更高的频率、更长的持续时间、更大的严重程度和更快的增长率。它们正在经历一个关键转变，干旱正在取代热浪成为主要限制因素。我们强调北半球高纬度地区SCDHWs的显著加剧以及南半球SCDHWs的持续时间延长，这对实现碳中和和粮食安全目标构成了被低估的威胁。
