美国加州大学Rong Fu团队提出，人为变暖已经在美国西部开启了一个以温度为主导的干旱时代。相关论文于2024年11月8日发表在《科学进展》杂志上。

从历史上看，美国西部 (WUS) 的气象干旱主要是由降水不足引起的。然而，研究观测分析表明，自2000年左右以来，地表温度的上升和由此产生的高蒸发需求，对WUS干旱严重程度（62%）和覆盖范围（66%）的影响大于降水不足。

研究人员对观测和气候模型模拟数据进行分析，结果显示，干旱期间蒸发需求的增加主要被归因于人为变暖，是干旱严重程度和覆盖范围增加的主要原因。2020-2022年，前所未有的WUS干旱体现了干旱驱动因素的这种转变，高蒸发需求占其严重程度的61%，而降水不足占39%。

气候模型模拟证实了这一转变，并预测在化石燃料驱动的发展情景（SSP5-8.5）下，像2020-2022年这样的干旱将从2022年之前的1年多一遇事件，转变为21世纪中期的60年一遇事件，到21世纪后期将转变为6年一遇事件。

附：英文原文

Title: Anthropogenic warming has ushered in an era of temperature-dominated droughts in the western United States

Author: Yizhou Zhuang, Rong Fu, Joel Lisonbee, Amanda M. Sheffield, Britt A. Parker, Genoveva Deheza

Issue&Volume: 2024-11-08

Abstract: Historically, meteorological drought in the western United States (WUS) has been driven primarily by precipitation deficits. However, our observational analysis shows that, since around 2000, rising surface temperature and the resulting high evaporative demand have contributed more to drought severity (62%) and coverage (66%) over the WUS than precipitation deficit. This increase in evaporative demand during droughts, mostly attributable to anthropogenic warming according to analyses of both observations and climate model simulations, is the main cause of the increased drought severity and coverage. The unprecedented 2020–2022 WUS drought exemplifies this shift in drought drivers, with high evaporative demand accounting for 61% of its severity, compared to 39% from precipitation deficit. Climate model simulations corroborate this shift and project that, under the fossil-fueled development scenario (SSP5-8.5), droughts like the 2020–2022 event will transition from a one-in-more-than-a-thousand-year event in the pre-2022 period to a 1-in-60-year event by the mid-21st century and to a 1-in-6-year event by the late-21st century.

DOI: adn9389

Source: https://www.science.org/doi/10.1126/sciadv.adn9389