据了解，复合干旱-热浪(CDHWs)加速了土壤的升温和干燥，引发了土壤复合干旱-热浪(SCDHWs)，并危及土壤生态系统的健康。然而，这些事件在世界范围内的行为及其对气候变暖的反应尚未得到充分研究。
研究发现，从1980-2023年，SCDHWs的频率、持续时间、峰值强度和严重程度在全球范围内呈上升趋势，受影响的土地面积也有所增加。这种上升趋势自2000年初以来尤为突出，预计将持续至本世纪，这一趋势主要受夏季SCDHWs调控，并因厄尔尼诺现象的而加剧。强烈的土壤变暖以及气候学上较低的土壤温度导致北部高纬度地区，局部热点地区的SCDHW严重程度升级，而持续时间的延长会导致南美洲北部地区出现这样的热点。
自然生态系统(特别是森林和湿地)向农田的转变以及森林的退化大大增强了SCDHWs的实力。从1980-2023年，全球SCDHWs在各方面都比CDHWs表现出更高的频率、更长的持续时间、更大的严重性和更快的增长速度。结果显示，它们正在经历一个关键的转变，干旱取代热浪成为主要的制约因素。研究人员强调，北半球高纬度地区的持续干旱和缺水现象显著加剧、南半球的持续干旱和缺水现象持续时间延长，对实现碳中和和粮食安全目标构成的威胁被低估。
附：英文原文
Title: Surging compound drought–heatwaves underrated in global soils
Author: 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
Issue&Volume: 2024-10-7
Abstract: 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 Nio. 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.
DOI: 10.1073/pnas.2410294121
Source: https://www.pnas.org/doi/abs/10.1073/pnas.2410294121