气候变化研究进展

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全球主要山地气候变化特征和异同——IPCC AR6 WGI报告和SROCC综合解读

马丽娟1,效存德2,康世昌3,4   

  1. 1 中国气象局国家气候中心,北京 100081;
    2 北京师范大学地表过程与资源生态国家重点实验室,北京 100875;
    3 中国科学院西北生态环境资源研究院冰冻圈科学国家重点实验室,兰州 730000;4 中国科学院大学,北京 100049
  • 收稿日期:2021-12-17 修回日期:2022-03-08 出版日期:2022-04-25 发布日期:2022-04-25
  • 通讯作者: 马丽娟
  • 基金资助:
    国家自然科学基金委重大项目;中国气象局创新发展专项

Characteristics, and Similarities and differences of climate change in major high mountains in the world—comprehensive interpretation of IPCC AR6 WGI report and SROCC

MA Li-Juan1, XIAO Cun-De2, KANG Shi-Chang3, 4   

  1. 1 National Climate Center, China Meteorological Administration, Beijing 100081, China;
    2 State Key Laboratory of Earth Surface Processes and Resource Ecology, Beijing Normal University, Beijing 100875, China;
    3 State Key Laboratory of Cryospheric Science, Northwest Institute of Eco-Environment and Resources, Chinese Academy of Sciences, Lanzhou 730000, China; 4 University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2021-12-17 Revised:2022-03-08 Online:2022-04-25 Published:2022-04-25
  • Contact: Lijuan MA

摘要: IPCC SROCC和AR6对高山区气候变化的评估表明,近期全球山地增暖速率提高,1980年代以来亚洲高山区增暖速率明显高于全球平均和其他高山区同期水平。各山地增暖普遍具有海拔依赖性,但机制复杂且区域差异大,除落基山脉未来气温增幅随海拔降低外,其余山地均随海拔有不同程度的升高。全球山地年降水在过去几十年没有明显趋势;预计未来北半球许多山地年降水将增加5%~20%,但极端降水变化的区域和季节差异较大,其中青藏高原喜马拉雅山脉极端降雨频次和强度都将增大。山地年最大雪水当量的减少在固?液态降水转化的海拔高度带更强,未来山地降雪和积雪变化不仅与排放情景有关,而且与海拔高度密切相关。2010—2019年全球山地冰川物质亏损较有观测记录以来的任何一个10年都多,亚洲高山区虽然冰川物质亏损速率较小,但每年亏损的冰量在全球四大高山区中仅次于安第斯山脉南段。预计山地冰川将持续退缩数十年或数百年,未来亚洲高山区冰川退缩对海平面上升的贡献将居全球四大高山区之首。山地多年冻土温度升高、厚度减薄,预计未来多年冻土将加速退化,即使在低温室气体排放情景下,21世纪末青藏高原多年冻土面积预计也将减少13.4%~27.7%。从评估的完整性和信度水平来看,山地观测和研究仍存在巨大差距。

关键词: 山地, IPCC, 气候变化, 冰冻圈, 积雪, 冰川, 冻土

Abstract: Assessments of IPCC AR6 and SROCC show that the global warming rate in High Mountain (HM) regions has increased recently. Since the 1980s, the warming rate in the High Mountain Asia (HMA) has been significantly higher than the average of the global mountains and that in other high mountains. The warming is generally altitudinal dependent, but the mechanism keeps complex and there are large regional differences. Except for the Rocky Mountains, the warming magnitude in other high mountain areas will increase with altitude to varying degrees. Although the global annual precipitation in mountain areas in the past few decades has shown no obvious trend, it is projected that the annual precipitation in many Northern Hemisphere mountain regions will increase by 5%?20% by the end of the 21st century, with great spatial and temporal discrepancies of extreme rainfall. The frequency and intensity of extreme rainfall will increase over the Qinghai-Tibet Plateau and the Himalayas. The decrease of annual maximum snow water equivalent in mountains is stronger in the altitude zone that solid precipitation is transforming towards liquid precipitation, and the change of mountain snow in the future is not only related to the emission scenario, but also closely related to the altitude. Global mountain glacier mass loss from 2010 to 2019 was greater than that in any other decade since observational records began. Although the rate of mass loss in HMA is smaller, the total ice volume loss is second only to that in the Southern Andes among global main mountain regions. It is projected that mountain glacier retreat will continue for decades or hundreds of years in the future, and the corresponding contribution to the sea level rise will be the largest in HMA among the four HM regions. The permafrost temperature and the thickness of active layer in mountains have been found increased and decreased, respectively. In the future, mountain permafrost will become more unstable with continued and accelerated degradation. Even under the low greenhouse gases emission scenario, the permafrost area on the Qinghai-Tibetan Plateau is expected to decrease by 13.4% to 27.7% by the end of the 21st century. However, from the perspective of the completeness and confidence level of the above assessment, there are still huge gaps in observations and researches in the mountains. The observing networks in mountains do not always follow standard observation procedures and are often not dense enough to capture fine-scale changes and potentially large-scale patterns. The discrepancies between satellite retrieval data and ground-based observations exist widely, especially for snow cover, which is still a recognized challenge. Therefore, immediate actions should be taken to strengthen the density of mountain observations, especially in three-dimensional space, in accordance with WMO standards, so as to improve the capacity of climate monitoring and services in mountain areas. In terms of information extraction from observations, refined, three-dimensional and accurate climate monitoring and assessment information is urgently needed to provide highly applicable scientific support for disaster management and climate change response. Projections of future climate change are made through global climate models, regional climate models, or their simplified versions, which are dynamically consistent in the way of representing physical processes and hence link changes in mountains with large-scale atmospheric forcing. However, existing models that specialized for mountain studies usually cover only a single mountain range, and there have been no initiatives such as model inter-comparison programs or coordinated downscaling trials addressing problems existing in mountains climate change. As a result, the direction of the future researches for mountain climate change lies, on the one hand, in the perspective of natural science, that is to continue to extract reliable information from observation data, support to improve the model resolution and simulation capability for complex underlying surfaces and quantify the contribution of mountain climate change in energy, water and carbon cycle and feedbacks from both macro and micro levels. On the other hand, from the perspective of supporting social sustainable development, to identify the climate change indicators that affect the stability of mountain society and ecosystem, supporting adaptation and mitigation of mountain climate change.

Key words: Mountain, IPCC, Climate change, Cryosphere, Snow cover, Glacier, Permafrost

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