An observation-based constraint on permafrost loss as a function of global warming
An observation-based constraint on permafrost loss as a function of global warming
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DOI：
10.1038/nclimate3262
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发表时间：
2017-05-01
影响因子：
30.7
通讯作者：
Westermann, S.
中科院分区：
文献类型：
--
作者：
Chadburn, S. E.;Burke, E. J.;Westermann, S.
覆盖陆地表面1500万公里(2)的永久冻土是地球系统中对气候变暖最敏感的组成部分之一(1，2)。永久冻土的消失将从根本上改变高纬度水文和生物地球化学循环，因此可能对气候变化提供非常重要的反馈(3-8)。最新的气候模型都预测高纬度土壤变暖，从而在未来气候变化下永久冻土融化，但永久冻土融化的幅度相差很大(9，10)。在这里，我们展示了在每一个模型中，它们现在的多年冻土和气温的空间分布可以用来推断多年冻土对未来全球变暖的敏感性。对观测到的多年冻土分布和气温使用相同的方法，我们估计在稳定在4.0(-1.1)(+1.0)百万千米(2)摄氏度(1西格玛置信度)时，多年冻土面积损失对全球平均变暖的敏感性，比以前的研究(9)高出约20%。我们的方法有助于评估COP21气候变化目标(11)：如果气候稳定在比工业化前水平高2摄氏度的水平，我们估计永久冻土面积最终将减少40%以上。稳定在1.5摄氏度而不是2摄氏度将节省大约200万公里的永久冻土。
Permafrost, which covers 15 million km(2) of the land surface, is one of the components of the Earth system that is most sensitive to warming(1,2). Loss of permafrost would radically change high-latitude hydrology and biogeochemical cycling, and could therefore provide very significant feedbacks on climate change(3-8). The latest climate models all predict warming of high-latitude soils and thus thawing of permafrost under future climate change, but with widely varying magnitudes of permafrost thaw(9,10). Here we show that in each of the models, their present-day spatial distribution of permafrost and air temperature can be used to infer the sensitivity of permafrost to future global warming. Using the same approach for the observed permafrost distribution and air temperature, we estimate a sensitivity of permafrost area loss to global mean warming at stabilization of 4.0(-1.1)(+1.0) million km(2) degrees C-1 (1 sigma confidence), which is around 20% higher than previous studies(9). Our method facilitates an assessment for COP21 climate change targets(11): if the climate is stabilized at 2 degrees C above pre-industrial levels, we estimate that the permafrost area would eventually be reduced by over 40%. Stabilizing at 1.5 degrees C rather than 2 degrees C would save approximately 2 million km(2) of permafrost.