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标题：Snowfall-albedo feedbacks could have led to deglaciation of snowball Earth starting from mid-latitudes
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作者：Philipp de Vrese ; Tobias Stacke ; Jeremy Caves Rugenstein 等
期刊名称：Communications Earth & Environment
电子版ISSN：2662-4435
出版年度：2021
卷号：2
期号：1
页码：1-9
DOI：10.1038/s43247-021-00160-4
语种：English
出版社：Nature Research
摘要：Simple and complex climate models suggest a hard snowball - a completely ice-covered planet - is one of the steady-states of Earth's climate. However, a seemingly insurmountable challenge to the hard-snowball hypothesis lies in the difficulty in explaining how the planet could have exited the glaciated state within a realistic range of atmospheric carbon dioxide concentrations. Here, we use simulations with the Earth system model MPI-ESM to demonstrate that terminal deglaciation could have been triggered by high dust deposition fluxes. In these simulations, deglaciation is not initiated in the tropics, where a strong hydrological cycle constantly regenerates fresh snow at the surface, which limits the dust accumulation and snow aging, resulting in a high surface albedo. Instead, comparatively low precipitation rates in the mid-latitudes in combination with high maximum temperatures facilitate lower albedos and snow dynamics that - for extreme dust fluxes - trigger deglaciation even at present-day carbon dioxide levels. Snowball Earth could have thawed at atmospheric CO2-levels comparable to the present as a result of low surface albedo in mid-latitudes from a combination dust deposition and low precipitation rates, according to Earth System Model simulations.