Impact of an AMOC weakening on the stability of the southern Amazon rainforest
The Atlantic Meridional Overturning Circulation (AMOC) and the Amazon rainforest are potential tipping elements of the Earth system, i.e., they may respond with abrupt and potentially irreversible state transitions to a gradual change in forcing once a critical forcing threshold is crossed. With pro...
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ftleibnizopen:oai:oai.leibnizopen.de:yJAGyYkBdbrxVwz6C53p 2023-08-27T04:09:49+02:00 Impact of an AMOC weakening on the stability of the southern Amazon rainforest Ciemer, Catrin Winkelmann, Ricarda Kurths, Jürgen Boers, Niklas 2021 application/pdf https://oa.tib.eu/renate/handle/123456789/7949 https://doi.org/10.34657/6990 eng eng Berlin Heidelberg : Springer CC BY 4.0 Unported https://creativecommons.org/licenses/by/4.0/ European physical journal special topics 230 (2021), Nr. 14-15 Thermohaline Circulation Climate Resilience 530 article Text 2021 ftleibnizopen https://doi.org/10.34657/6990 2023-08-06T23:13:08Z The Atlantic Meridional Overturning Circulation (AMOC) and the Amazon rainforest are potential tipping elements of the Earth system, i.e., they may respond with abrupt and potentially irreversible state transitions to a gradual change in forcing once a critical forcing threshold is crossed. With progressing global warming, it becomes more likely that the Amazon will reach such a critical threshold, due to projected reductions of precipitation in tropical South America, which would in turn trigger vegetation transitions from tropical forest to savanna. At the same time, global warming has likely already contributed to a weakening of the AMOC, which induces changes in tropical Atlantic sea-surface temperature (SST) patterns that in turn affect rainfall patterns in the Amazon. A large-scale decline or even dieback of the Amazon rainforest would imply the loss of the largest terrestrial carbon sink, and thereby have drastic consequences for the global climate. Here, we assess the direct impact of greenhouse gas-driven warming of the tropical Atlantic ocean on Amazon rainfall. In addition, we estimate the effect of an AMOC slowdown or collapse, e. g. induced by freshwater flux into the North Atlantic due to melting of the Greenland Ice Sheet, on Amazon rainfall. In order to provide a clear explanation of the underlying dynamics, we use a simple, but robust mathematical approach (based on the classical Stommel two-box model), ensuring consistency with a comprehensive general circulation model (HadGEM3). We find that these two processes, both caused by global warming, are likely to have competing impacts on the rainfall sum in the Amazon, and hence on the stability of the Amazon rainforest. A future AMOC decline may thus counteract direct global-warming-induced rainfall reductions. Tipping of the AMOC from the strong to the weak mode may therefore have a stabilizing effect on the Amazon rainforest. publishedVersion Article in Journal/Newspaper Greenland Ice Sheet North Atlantic LeibnizOpen (The Leibniz Association) Greenland |
institution |
Open Polar |
collection |
LeibnizOpen (The Leibniz Association) |
op_collection_id |
ftleibnizopen |
language |
English |
topic |
Thermohaline Circulation Climate Resilience 530 |
spellingShingle |
Thermohaline Circulation Climate Resilience 530 Ciemer, Catrin Winkelmann, Ricarda Kurths, Jürgen Boers, Niklas Impact of an AMOC weakening on the stability of the southern Amazon rainforest |
topic_facet |
Thermohaline Circulation Climate Resilience 530 |
description |
The Atlantic Meridional Overturning Circulation (AMOC) and the Amazon rainforest are potential tipping elements of the Earth system, i.e., they may respond with abrupt and potentially irreversible state transitions to a gradual change in forcing once a critical forcing threshold is crossed. With progressing global warming, it becomes more likely that the Amazon will reach such a critical threshold, due to projected reductions of precipitation in tropical South America, which would in turn trigger vegetation transitions from tropical forest to savanna. At the same time, global warming has likely already contributed to a weakening of the AMOC, which induces changes in tropical Atlantic sea-surface temperature (SST) patterns that in turn affect rainfall patterns in the Amazon. A large-scale decline or even dieback of the Amazon rainforest would imply the loss of the largest terrestrial carbon sink, and thereby have drastic consequences for the global climate. Here, we assess the direct impact of greenhouse gas-driven warming of the tropical Atlantic ocean on Amazon rainfall. In addition, we estimate the effect of an AMOC slowdown or collapse, e. g. induced by freshwater flux into the North Atlantic due to melting of the Greenland Ice Sheet, on Amazon rainfall. In order to provide a clear explanation of the underlying dynamics, we use a simple, but robust mathematical approach (based on the classical Stommel two-box model), ensuring consistency with a comprehensive general circulation model (HadGEM3). We find that these two processes, both caused by global warming, are likely to have competing impacts on the rainfall sum in the Amazon, and hence on the stability of the Amazon rainforest. A future AMOC decline may thus counteract direct global-warming-induced rainfall reductions. Tipping of the AMOC from the strong to the weak mode may therefore have a stabilizing effect on the Amazon rainforest. publishedVersion |
format |
Article in Journal/Newspaper |
author |
Ciemer, Catrin Winkelmann, Ricarda Kurths, Jürgen Boers, Niklas |
author_facet |
Ciemer, Catrin Winkelmann, Ricarda Kurths, Jürgen Boers, Niklas |
author_sort |
Ciemer, Catrin |
title |
Impact of an AMOC weakening on the stability of the southern Amazon rainforest |
title_short |
Impact of an AMOC weakening on the stability of the southern Amazon rainforest |
title_full |
Impact of an AMOC weakening on the stability of the southern Amazon rainforest |
title_fullStr |
Impact of an AMOC weakening on the stability of the southern Amazon rainforest |
title_full_unstemmed |
Impact of an AMOC weakening on the stability of the southern Amazon rainforest |
title_sort |
impact of an amoc weakening on the stability of the southern amazon rainforest |
publisher |
Berlin |
publishDate |
2021 |
url |
https://oa.tib.eu/renate/handle/123456789/7949 https://doi.org/10.34657/6990 |
geographic |
Greenland |
geographic_facet |
Greenland |
genre |
Greenland Ice Sheet North Atlantic |
genre_facet |
Greenland Ice Sheet North Atlantic |
op_source |
European physical journal special topics 230 (2021), Nr. 14-15 |
op_rights |
CC BY 4.0 Unported https://creativecommons.org/licenses/by/4.0/ |
op_doi |
https://doi.org/10.34657/6990 |
_version_ |
1775351410555092992 |