摘要
在全球气候变化日益加剧的背景下,全球干旱增强速率在过去数十年显著加快,干旱模式从缓旱转向骤旱,且未来情景下骤旱的频率和强度将持续上升。骤旱作为一种快速发生且破坏性强的极端气候事件,对全球社会经济和生态环境安全造成严峻挑战。笔者梳理了骤旱概念的演变,明确了以“快速增强、干旱形成、产生影响”为核心3要素的定义框架,深入解构了驱动骤旱的物理机制,论证了全球变化如何通过大气、海洋和陆地3个层面的协同作用非线性地放大骤旱风险,深入剖析其在全球变化框架下的核心科学问题。骤旱的危害性体现在其与热浪等灾害并发形成的复合效应,以及对农业、生态与水资源产生的级联影响。在此基础上,探讨了应对骤旱的适应与减缓策略,强调了构建高时空分辨率的多指标融合监测预警系统、突破次季节到季节尺度的预报瓶颈、以及建立具有快速响应能力和系统性风险治理适应性治理框架的必要性,旨在为深化骤旱的科学理解、提升防灾减灾能力及制定相关气候政策提供科学依据。
[Background]Global climate change is challenging the traditional paradigm of slow-onset drought,fostering a shift towards“flash droughts”—extreme events with rapid development and severe destructive potential.Their sudden onset provides minimal time for response,amplifying their ecological and socioeconomic impacts and creating an urgent need to understand their mechanisms and patterns.This paper addresses this challenge by systematically reviewing and synthesizing the current scientific understanding of flash droughts,their drivers,and impacts under global change.[Methods]This paper first traces the evolution of the flash drought concept,clarifying the current definition framework,which centers on three core elements.It further deconstructs the physical mechanisms,demonstrating how global change non-linearly amplifies flash drought risk through synergistic interactions across the atmosphere,ocean,and land,and examines the core scientific questions within this framework.[Results]1)A unifying definition framework distinguishes flash droughts through three criteria:a rapid onset,an obvious moisture deficit(e.g.,soil moisture below the 20th percentile),and substantial impacts on one or more sectors.In contrast to traditional droughts,flash droughts develop over weeks instead of months,are driven by both precipitation deficits and high evaporative demand,and exhibit lower predictability.2)Observational and modeling evidence indicates a significant acceleration in the global intensification rate of droughts over recent decades,with future scenarios projecting a continued rise in the frequency and intensity of flash drought events.A notable global transition from slow-onset to flash droughts is already evident across 74%of regions.Under high-emission scenarios,the annual risk to croplands is projected to rise significantly in North America and Europe by 2100,and the frequency of flash droughts in China is expected to increase across more than 65%of the land area.3)The formation of flash droughts is driven by a severe surface water imbalance—a sudden precipitation deficit combined with high evaporative demand.This is amplified by large-scale oceanic anomalies(e.g.,El Niño–Southern Oscillation,ENSO),reinforcing land-atmosphere feedbacks that accelerate drying,and changes in land surface conditions like earlier snowmelt.4)Impacts of flash drought are rapid,severe,and cascading,encompassing major agricultural losses,sharp declines in ecosystem productivity,increased wildfire risk,and reductions in water resources.[Conclusions]This paper confirms that global change is a primary driver and amplifier of flash drought risk,catalyzing a global shift toward these rapid-onset events.These findings underscore the inadequacy of traditional drought management frameworks,and highlight an urgent need to:1)Develop high-resolution,multi-indicator integrated monitoring and early warning systems;2)Overcome forecasting limitations at sub-seasonal to seasonal timescales;and 3)Establish comprehensive risk governance frameworks from local to global scales.Ultimately,this paper aims to advance scientific understanding of flash droughts,strengthen disaster risk reduction capacities,and provide a scientific basis for climate-related policymaking.
作者
胡金龙
缪驰远
柴元方
苟娇娇
HU Jinlong;MIAO Chiyuan;CHAI Yuanfang;GOU Jiaojiao(State Key Laboratory of Earth Surface Processes and Disaster Risk Reduction,Faculty of Geographical Science,Beijing Normal University,100875,Beijing,China)
出处
《中国水土保持科学》
北大核心
2025年第4期1-11,共11页
Science of Soil and Water Conservation
基金
国家自然科学基金区域创新发展联合基金“变化环境下干热河谷区生态系统服务功能时空演变机理与优化”(U24A20572)
国家重点研发计划项目“典型干旱区气候变化与经济社会适应”(2024YFF0809301)。
关键词
骤旱
干旱
全球变化
陆–气耦合
复合极端事件
flash drought
drought
global change
land-atmosphere coupling
combined extreme events
