Snowfall-albedo feedbacks could have led to deglaciation of snowball Earth starting from mid-latitudes
| Autor: | Victor Brovkin, Philipp de Vrese, Tobias Stacke, Jason C. Goodman, Jeremy K. Caves Rugenstein |
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| Rok vydání: | 2021 |
| Předmět: |
Carbon dioxide in Earth's atmosphere
010504 meteorology & atmospheric sciences Albedo 010502 geochemistry & geophysics Snow Atmospheric sciences 01 natural sciences Deglaciation General Earth and Planetary Sciences Snowball Earth Environmental science Climate model Precipitation Water cycle 0105 earth and related environmental sciences General Environmental Science |
| Zdroj: | Communications Earth & Environment |
| ISSN: | 2662-4435 |
| Popis: | 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 |
| Databáze: | OpenAIRE |
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