IPCC AR6报告关于不同类型干旱变化研究的新进展与启示

New progress and enlightenment on different types of drought changes from IPCC Sixth Assessment Report

  • 摘要: 基于IPCC第一工作组(WGI)第六次评估报告(AR6),从干旱的定义和类型、干旱的驱动因素、监测到的干旱变化、干旱的归因以及预估5个方面进行了分析和总结。IPCC评估指出:(1)在全球变暖的背景下,监测到的气象和农业干旱的变化在全球尺度上并不显著,但干旱频发区域呈现不同程度的增加趋势。这种增加的趋势表明,人为气候变化在加剧区域干旱中的作用不容忽视。在气象干旱的变化趋势归因中,对人类活动影响的认识信度仍然不高。(2)在农业干旱和生态干旱方面,大部分区域能够归因于人类活动引起的变化(中等-高信度;在水文干旱变化中,除人为引起的气候变化外,水资源管理和土地利用也是局地影响的重要因素(中等信度)。(3)在未来的干旱预估中,全球更多的区域将经历更严重更频繁的干旱事件,农业和生态干旱也将随着升温水平的提高而变得频繁和强烈。(4)在对不同类型干旱的变化评估中,重点涉及了大气蒸发需求(AED)这一关键变量。AED的变化不仅是对气候变暖的直接响应,而且作为干旱变化的驱动因子,影响植被的生理过程,同时AED的变化也是对蒸散发变化的一种反馈。在未来气候变化不断加剧背景下,不同类型干旱间的相互作用将变得更为复杂。未来中国干旱的研究和业务应深入探究不同类型干旱变化的联系;基于多元数据和多重证据的支撑,加强跨学科研究以及干旱变化与局地人类活动影响和植被生态反馈的综合研究。

     

    Abstract: This paper reviews the definition and type of droughts, as well as their driving factors, historical changes, attributions and projections based on the Working Group I (WGI) contribution to the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report (AR6) on the physical science basis of climate change. The IPCC AR6 new results show that: (1) The changes in meteorological and agricultural droughts are not significant on a global scale, but display an increasing trend in some regions. The increasing trend shows that anthropogenic climate change plays an important role in exacerbating droughts. For meteorological droughts, the understanding of the influence of human activities is of low confidence. (2) Agricultural and ecological droughts in most regions can be attributed to human activities (medium to high confidence); for hydrological droughts, in addition to human-induced climate change, regional water resources management and land use are also important factors (medium confidence). (3) In the future projections, more regions around the world will experience more severe and frequent drought events in the future. Agricultural and ecological droughts will also become more frequent and intense as the temperature rises. (4) In the analysis of assessment of changes in different types of droughts, the key variable of atmospheric evaporation demand (AED) is emphasized. Changes in AED are not only a direct response to climate warming, but also a driving factor for drought changes, affecting the physiological processes of vegetation. Meanwhile, changes in AED also feedback to evapotranspiration. The interactions between different types of droughts will become more complicated under the background of intensifying climate change. In the future, the research and operational service of droughts in China should deepen our understanding of connections between changes of different types of droughts, strengthen multi-disciplinary cooperation and explore feedback loops between drought changes, local human activities and ecological processes based on multiple datasets and various evidences.

     

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