Keeping global warming within 1.5 °C constrains emergence of aridification
Keeping global warming within 1.5 °C constrains emergence of aridification
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DOI：
10.1038/s41558-017-0034-4
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发表时间：
2018-01-01
影响因子：
30.7
通讯作者：
Feng, Song
中科院分区：
文献类型：
--
作者：
Park, Chang-Eui;Jeong, Su-Jong;Feng, Song
干旱--大气水供应(降水；P)与需求(潜在蒸散；PET)的比率--预计将因人为气候变化而减少(即，地区将变得更加干旱)，加剧土地退化和荒漠化(1-6)。然而，相对于自然变化的重大变化的时间--这里定义为出现干旱的时间(TOEA)--是未知的，尽管它在设计和执行缓解政策方面很重要(7-10)。在这里，我们根据27个全球气候模型(GCM)在典型集中路径(RCP)RCP4.5和RCP8.5下的预测来估计TOEA，并在这样做的过程中，确定在全球平均变暖达到比工业化前水平高1.5摄氏度和2摄氏度之前出现在哪里。根据每个网格单元的集合中值TOEA，在全球平均气温变化的集合中值达到2摄氏度之前，干旱化分别出现在总陆地表面的32%(RCP4.5)和24%(RCP8.5)以上。此外，在上述区域中，如果最大全球变暖水平被限制在1.5摄氏度以内，大约三分之二的地区就可以避免气候变化。因此，及早采取行动实现1.5摄氏度的温度目标可以显著降低大面积区域面临严重干旱和相关影响的可能性。
Aridity-the ratio of atmospheric water supply (precipitation; P) to demand (potential evapotranspiration; PET)-is projected to decrease (that is, areas will become drier) as a consequence of anthropogenic climate change, exacerbating land degradation and desertification(1-6). However, the timing of significant aridification relative to natural variability-defined here as the time of emergence for aridification (ToEA)-is unknown, despite its importance in designing and implementing mitigation policies(7-10). Here we estimate ToEA from projections of 27 global climate models (GCMs) under representative concentration pathways (RCPs) RCP4.5 and RCP8.5, and in doing so, identify where emergence occurs before global mean warming reaches 1.5 degrees C and 2 degrees C above the pre-industrial level. On the basis of the ensemble median ToEA for each grid cell, aridification emerges over 32% (RCP4.5) and 24% (RCP8.5) of the total land surface before the ensemble median of global mean temperature change reaches 2 degrees C in each scenario. Moreover, ToEA is avoided in about two-thirds of the above regions if the maximum global warming level is limited to 1.5 degrees C. Early action for accomplishing the 1.5 degrees C temperature goal can therefore markedly reduce the likelihood that large regions will face substantial aridification and related impacts.