Permafrost degradation induced by climate warming is widely observed in the Northern Hemisphere. However, changes in permafrost sensitivity to climate warming (PSCW) in the future remains unclear. This study examined the changes in permafrost distribution in the Northern Hemisphere under global warming of 1.5 C and 2 C, and then characterized the spatial and temporal characteristics of PSCW. Global warming of 1.5 C and 2 C would result in 17.8 5.3% and 28.3 7.2% degradation of permafrost area under the climate scenario of Representative Concentration Pathway (RCP) 4.5, respectively, and 18.7 4.6% and 28.1 7.2% under the RCP 8.5, respectively. Permafrost tends to be more sensitive to climate change under the RCP 8.5 than RCP 4.5. PSCW shows small temporal variations in the 21st century under both RCPs, indicating a relatively stable sensitivity to warming on a hemisphere scale. However, PSCW varies greatly among regions, with high values at low latitudes and low values towards high latitudes. Air temperature is a major cause for the spatial heterogeneity of PSCW, explaining 66% of its variations. Permafrost under a warmer climate scenario tends to be more sensitive to the warming. Reducing snow depth and rising air temperature collectively enhances the permafrost sensitivity. Increasing in soil water content, by contrast, reduces the effect of warming. Permafrost in the south of the Northern Hemisphere is most vulnerable to climate warming. Our study highlights that permafrost in the region will respond differently under different warming scenarios across space (e.g. north vs south) and time (e.g. summer vs winter) in this century.

在北半球，由于气候变暖而引起的多年冻土退化已被广泛观察到。然而，未来永冻土对气候变暖（PSCW）的敏感性变化尚不清楚。这项研究研究了在全球变暖1.5 C和2 C的情况下北半球多年冻土分布的变化，然后描述了PSCW的时空特征。在代表浓度途径（RCP）4.5的气候情景下，全球变暖1.5 C和2 C会分别导致永久冻土面积降低17.8 5.3％和28.3 7.2％，而在RCP 8.5下则分别导致18.7 4.6％和28.1 7.2％，分别。在RCP 8.5之下，永久冻土比RCP 4.5对气候变化更敏感。在两种RCP的共同作用下，PSCW在21世纪都表现出较小的时间变化，表明对半球尺度的变暖具有相对稳定的敏感性。但是，PSCW在各地区之间差异很大，在低纬度地区值较高，而在高纬度地区值较低。气温是造成PSCW空间异质性的主要原因，可以解释其变化的66％。气候变暖情况下的永久冻土往往对变暖更加敏感。降低积雪深度和升高气温共同提高了多年冻土的敏感性。相反，增加土壤含水量会降低变暖的影响。北半球南部的永久冻土最容易受到气候变暖的影响。我们的研究强调，本世纪，该地区的多年冻土在不同的变暖情景下（跨北向南）和时间（如夏季对冬季）将有不同的响应。