Early Eocene low orography and high methane enhance Arctic warming via polar stratospheric clouds
Proxy data suggest that the early Eocene (similar to 56-47.8 million years ago) was characterized by a much weaker equator-to-pole temperature gradient than today. However, general circulation models consistently underestimate high-latitude temperatures indicated by proxy records, suggesting that th...
Published in: | Nature Geoscience |
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Online Access: | https://doi.org/10.1038/s41561-023-01298-w |
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ftncar:oai:drupal-site.org:articles_26845 2024-04-14T08:05:08+00:00 Early Eocene low orography and high methane enhance Arctic warming via polar stratospheric clouds Dutta, Deepashree (author) Jucker, Martin (author) Sherwood, Steven C. (author) Meissner, Katrin J. (author) Sen Gupta, Alex (author) Zhu, Jiang (author) 2023-11-07 https://doi.org/10.1038/s41561-023-01298-w en eng Nature Geoscience--Nat. Geosci.--1752-0894--1752-0908 Data for the article "Early Eocene low orography and high methane enhance Arctic warming via polar stratospheric clouds"--10.6084/m9.figshare.23690946 articles:26845 doi:10.1038/s41561-023-01298-w ark:/85065/d7w09b16 Copyright author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. article Text 2023 ftncar https://doi.org/10.1038/s41561-023-01298-w 2024-03-21T18:00:26Z Proxy data suggest that the early Eocene (similar to 56-47.8 million years ago) was characterized by a much weaker equator-to-pole temperature gradient than today. However, general circulation models consistently underestimate high-latitude temperatures indicated by proxy records, suggesting that they may miss important processes. Previous studies hypothesized that wintertime polar stratospheric clouds may have played an important role in Arctic warming through greenhouse forcing, but these studies did not consider the effects of atmospheric chemistry or the early Eocene topography. Here we examine these factors using a high-top atmospheric model with interactive chemistry. The lower orography in the low- to mid-latitude Northern Hemisphere early Eocene weakens the stratospheric circulation which, in combination with sufficiently high methane concentrations, leads to a substantial increase in polar stratospheric clouds in the Arctic winter. Furthermore, an increase in early Eocene polar stratospheric clouds due to a 16- to 64-fold higher than pre-industrial methane concentration results in a radiative forcing larger than the direct greenhouse effect from the methane itself. This polar stratospheric cloud-induced radiative forcing could cause up to 7.4 K of Arctic surface warming. These results point to the potential for nonlinear interactions between individual forcings. 1852977 Article in Journal/Newspaper Arctic Arctic OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) Arctic Nature Geoscience 16 11 1027 1032 |
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Open Polar |
collection |
OpenSky (NCAR/UCAR - National Center for Atmospheric Research/University Corporation for Atmospheric Research) |
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ftncar |
language |
English |
description |
Proxy data suggest that the early Eocene (similar to 56-47.8 million years ago) was characterized by a much weaker equator-to-pole temperature gradient than today. However, general circulation models consistently underestimate high-latitude temperatures indicated by proxy records, suggesting that they may miss important processes. Previous studies hypothesized that wintertime polar stratospheric clouds may have played an important role in Arctic warming through greenhouse forcing, but these studies did not consider the effects of atmospheric chemistry or the early Eocene topography. Here we examine these factors using a high-top atmospheric model with interactive chemistry. The lower orography in the low- to mid-latitude Northern Hemisphere early Eocene weakens the stratospheric circulation which, in combination with sufficiently high methane concentrations, leads to a substantial increase in polar stratospheric clouds in the Arctic winter. Furthermore, an increase in early Eocene polar stratospheric clouds due to a 16- to 64-fold higher than pre-industrial methane concentration results in a radiative forcing larger than the direct greenhouse effect from the methane itself. This polar stratospheric cloud-induced radiative forcing could cause up to 7.4 K of Arctic surface warming. These results point to the potential for nonlinear interactions between individual forcings. 1852977 |
author2 |
Dutta, Deepashree (author) Jucker, Martin (author) Sherwood, Steven C. (author) Meissner, Katrin J. (author) Sen Gupta, Alex (author) Zhu, Jiang (author) |
format |
Article in Journal/Newspaper |
title |
Early Eocene low orography and high methane enhance Arctic warming via polar stratospheric clouds |
spellingShingle |
Early Eocene low orography and high methane enhance Arctic warming via polar stratospheric clouds |
title_short |
Early Eocene low orography and high methane enhance Arctic warming via polar stratospheric clouds |
title_full |
Early Eocene low orography and high methane enhance Arctic warming via polar stratospheric clouds |
title_fullStr |
Early Eocene low orography and high methane enhance Arctic warming via polar stratospheric clouds |
title_full_unstemmed |
Early Eocene low orography and high methane enhance Arctic warming via polar stratospheric clouds |
title_sort |
early eocene low orography and high methane enhance arctic warming via polar stratospheric clouds |
publishDate |
2023 |
url |
https://doi.org/10.1038/s41561-023-01298-w |
geographic |
Arctic |
geographic_facet |
Arctic |
genre |
Arctic Arctic |
genre_facet |
Arctic Arctic |
op_relation |
Nature Geoscience--Nat. Geosci.--1752-0894--1752-0908 Data for the article "Early Eocene low orography and high methane enhance Arctic warming via polar stratospheric clouds"--10.6084/m9.figshare.23690946 articles:26845 doi:10.1038/s41561-023-01298-w ark:/85065/d7w09b16 |
op_rights |
Copyright author(s). This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License. |
op_doi |
https://doi.org/10.1038/s41561-023-01298-w |
container_title |
Nature Geoscience |
container_volume |
16 |
container_issue |
11 |
container_start_page |
1027 |
op_container_end_page |
1032 |
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1796301976049287168 |