Permafrost degradation and associated ground settlement estimation under 2°C global warming
Permafrost degradation and associated ground settlement estimation under 2°C global warming
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DOI：
10.1007/s00382-016-3469-9
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发表时间：
2017-10-01
期刊：
影响因子：
4.6
通讯作者：
Wang, Huijun
中科院分区：
文献类型：
--
作者：
Guo, Donglin;Wang, Huijun
全球升温比工业化前水平高2摄氏度被认为是全球平均温度不应超过的阈值，以避免对气候系统的危险干扰。然而，由于全球气候变化的不一致性，这一全球平均目标对不同区域的影响不同。多年冻土对气候变化很敏感，而且广泛分布在高纬度和高海拔地区，预计这些地区的变暖幅度最大。即使全球变暖2摄氏度，永久冻土也会受到严重影响，进而影响水资源，生态系统和基础设施等其他系统。利用10个耦合模型相互比较项目第五阶段模型的空气和土壤温度数据，结合冻土的观测，我们研究了2摄氏度全球变暖下的冻土融化和相关的地面沉降。结果表明，气候模式产生的总体平均多年冻土面积为14.01 × 10（6）km（2），这与观测中的13.89 × 10（6）km（2）（北纬45度以北）的面积相比是合理的。该模型预测，在6米深的土壤温度将增加2.34-2.67摄氏度的区域平均相对于1990-2000年，增加加剧与纬度的增加。活动层厚度也将增加0.42-0.45 m，但与土壤温度不同，由于高纬度地区的冻土温度明显较低，活动层厚度的增加随着纬度的增加而减弱。多年冻土范围将明显向北退缩，减少24-26%，冻土融化引起的地面沉降面积平均为3.8-15 cm。在这项研究中可能存在的不确定性可能主要是由于不太准确的地面冰含量数据和粗糙的水平分辨率的模式。
Global warming of 2 degrees C above preindustrial levels has been considered to be the threshold that should not be exceeded by the global mean temperature to avoid dangerous interference with the climate system. However, this global mean target has different implications for different regions owing to the globally nonuniform climate change characteristics. Permafrost is sensitive to climate change; moreover, it is widely distributed in high-latitude and high-altitude regions where the greatest warming is predicted. Permafrost is expected to be severely affected by even the 2 degrees C global warming, which, in turn, affects other systems such as water resources, ecosystems, and infrastructures. Using air and soil temperature data from ten coupled model intercomparison project phase five models combined with observations of frozen ground, we investigated the permafrost thaw and associated ground settlement under 2 degrees C global warming. Results show that the climate models produced an ensemble mean permafrost area of 14.01 x 10(6) km(2), which compares reasonably with the area of 13.89 x 10(6) km(2) (north of 45A degrees N) in the observations. The models predict that the soil temperature at 6 m depth will increase by 2.34-2.67 degrees C on area average relative to 1990-2000, and the increase intensifies with increasing latitude. The active layer thickness will also increase by 0.42-0.45 m, but dissimilar to soil temperature, the increase weakens with increasing latitude due to the distinctly cooler permafrost at higher latitudes. The permafrost extent will obviously retreat north and decrease by 24-26% and the ground settlement owing to permafrost thaw is estimated at 3.8-15 cm on area average. Possible uncertainties in this study may be mostly attributed to the less accurate ground ice content data and coarse horizontal resolution of the models.