Diffenbaugh Noah S, Scherer Martin, Ashfaq Moetasim
Department of Environmental Earth System Science and Woods Institute for the Environment, Stanford University, CA, USA.
Nat Clim Chang. 2013 Apr 1;3:379-384. doi: 10.1038/nclimate1732.
Snow accumulation is critical for water availability in the northern hemisphere , raising concern that global warming could have important impacts on natural and human systems in snow-dependent regions . Although regional hydrologic changes have been observed (e.g., ), the time of emergence of extreme changes in snow accumulation and melt remains a key unknown for assessing climate change impacts . We find that the CMIP5 global climate model ensemble exhibits an imminent shift towards low snow years in the northern hemisphere, with areas of western North America, northeastern Europe, and the Greater Himalaya showing the strongest emergence during the near-term decades and at 2°C global warming. The occurrence of extremely low snow years becomes widespread by the late-21 century, as do the occurrence of extremely high early-season snowmelt and runoff (implying increasing flood risk), and extremely low late-season snowmelt and runoff (implying increasing water stress). Our results suggest that many snow-dependent regions of the northern hemisphere are likely to experience increasing stress from low snow years within the next three decades, and from extreme changes in snow-dominated water resources if global warming exceeds 2°C above the pre-industrial baseline.
积雪对于北半球的水资源供应至关重要，这引发了人们对全球变暖可能对依赖积雪地区的自然和人类系统产生重大影响的担忧。尽管已经观察到区域水文变化（例如，），但积雪积累和融化的极端变化出现的时间仍是评估气候变化影响的一个关键未知因素。我们发现，CMIP5全球气候模型集合显示北半球即将向低雪年份转变，北美西部、欧洲东北部和大喜马拉雅地区在近几十年以及全球变暖2°C时出现的变化最为明显。到21世纪后期，极低雪年份的情况变得普遍，极早季融雪和径流（意味着洪水风险增加）以及极晚季融雪和径流（意味着水资源压力增加）的情况也变得普遍。我们的结果表明，北半球许多依赖积雪的地区在未来三十年可能会因低雪年份而面临越来越大的压力，如果全球变暖超过工业化前基线2°C，还会因以积雪为主的水资源的极端变化而面临压力。
