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Anthropogenic aerosol and cryosphere changes drive Earth’s strong but transient clear-sky hemispheric albedo asymmetry

A striking feature of the Earth system is that the Northern and Southern Hemispheres reflect identical amounts of sunlight. This hemispheric albedo symmetry comprises two asymmetries: The Northern Hemisphere is more reflective in clear skies, whereas the Southern Hemisphere is cloudier. Here we show...

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Autores principales: Diamond, Michael S., Gristey, Jake J., Kay, Jennifer E., Feingold, Graham
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group UK 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9466336/
https://www.ncbi.nlm.nih.gov/pubmed/36118252
http://dx.doi.org/10.1038/s43247-022-00546-y
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author Diamond, Michael S.
Gristey, Jake J.
Kay, Jennifer E.
Feingold, Graham
author_facet Diamond, Michael S.
Gristey, Jake J.
Kay, Jennifer E.
Feingold, Graham
author_sort Diamond, Michael S.
collection PubMed
description A striking feature of the Earth system is that the Northern and Southern Hemispheres reflect identical amounts of sunlight. This hemispheric albedo symmetry comprises two asymmetries: The Northern Hemisphere is more reflective in clear skies, whereas the Southern Hemisphere is cloudier. Here we show that the hemispheric reflection contrast from differences in continental coverage is offset by greater reflection from the Antarctic than the Arctic, allowing the net clear-sky asymmetry to be dominated by aerosol. Climate model simulations suggest that historical anthropogenic aerosol emissions drove a large increase in the clear-sky asymmetry that would reverse in future low-emission scenarios. High-emission scenarios also show decreasing asymmetry, instead driven by declines in Northern Hemisphere ice and snow cover. Strong clear-sky hemispheric albedo asymmetry is therefore a transient feature of Earth’s climate. If all-sky symmetry is maintained, compensating cloud changes would have uncertain but important implications for Earth’s energy balance and hydrological cycle.
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spelling pubmed-94663362022-09-12 Anthropogenic aerosol and cryosphere changes drive Earth’s strong but transient clear-sky hemispheric albedo asymmetry Diamond, Michael S. Gristey, Jake J. Kay, Jennifer E. Feingold, Graham Commun Earth Environ Article A striking feature of the Earth system is that the Northern and Southern Hemispheres reflect identical amounts of sunlight. This hemispheric albedo symmetry comprises two asymmetries: The Northern Hemisphere is more reflective in clear skies, whereas the Southern Hemisphere is cloudier. Here we show that the hemispheric reflection contrast from differences in continental coverage is offset by greater reflection from the Antarctic than the Arctic, allowing the net clear-sky asymmetry to be dominated by aerosol. Climate model simulations suggest that historical anthropogenic aerosol emissions drove a large increase in the clear-sky asymmetry that would reverse in future low-emission scenarios. High-emission scenarios also show decreasing asymmetry, instead driven by declines in Northern Hemisphere ice and snow cover. Strong clear-sky hemispheric albedo asymmetry is therefore a transient feature of Earth’s climate. If all-sky symmetry is maintained, compensating cloud changes would have uncertain but important implications for Earth’s energy balance and hydrological cycle. Nature Publishing Group UK 2022-09-12 2022 /pmc/articles/PMC9466336/ /pubmed/36118252 http://dx.doi.org/10.1038/s43247-022-00546-y Text en © The Author(s) 2022 https://creativecommons.org/licenses/by/4.0/Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons license and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) .
spellingShingle Article
Diamond, Michael S.
Gristey, Jake J.
Kay, Jennifer E.
Feingold, Graham
Anthropogenic aerosol and cryosphere changes drive Earth’s strong but transient clear-sky hemispheric albedo asymmetry
title Anthropogenic aerosol and cryosphere changes drive Earth’s strong but transient clear-sky hemispheric albedo asymmetry
title_full Anthropogenic aerosol and cryosphere changes drive Earth’s strong but transient clear-sky hemispheric albedo asymmetry
title_fullStr Anthropogenic aerosol and cryosphere changes drive Earth’s strong but transient clear-sky hemispheric albedo asymmetry
title_full_unstemmed Anthropogenic aerosol and cryosphere changes drive Earth’s strong but transient clear-sky hemispheric albedo asymmetry
title_short Anthropogenic aerosol and cryosphere changes drive Earth’s strong but transient clear-sky hemispheric albedo asymmetry
title_sort anthropogenic aerosol and cryosphere changes drive earth’s strong but transient clear-sky hemispheric albedo asymmetry
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9466336/
https://www.ncbi.nlm.nih.gov/pubmed/36118252
http://dx.doi.org/10.1038/s43247-022-00546-y
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