Past and future response of the North Atlantic warming hole to anthropogenic forcing

<p>Most of the North Atlantic ocean has warmed over the last decades, except a region located over the subpolar gyre, known as the North Atlantic “warming hole” (WH), where sea surface temperature (SST) has in contrast decreased. Previous assessments have attributed part of this cooling to the...

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Main Author: S. Qasmi
Format: Article
Language:English
Published: Copernicus Publications 2023-06-01
Series:Earth System Dynamics
Online Access:https://esd.copernicus.org/articles/14/685/2023/esd-14-685-2023.pdf
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author S. Qasmi
author_facet S. Qasmi
author_sort S. Qasmi
collection DOAJ
description <p>Most of the North Atlantic ocean has warmed over the last decades, except a region located over the subpolar gyre, known as the North Atlantic “warming hole” (WH), where sea surface temperature (SST) has in contrast decreased. Previous assessments have attributed part of this cooling to the anthropogenic forcings (ANT) – aerosols (AER) and greenhouse gases (GHGs) – modulated by decadal internal variability. Here, I use an innovative and proven statistical method which combines climate models and observations to confirm the anthropogenic role in the cooling of the warming hole. The impact of the aerosols is an increase in SST which is opposed to the effect of GHGs. The latter largely contribute to the cooling of the warming hole over the historical period. Yet, large uncertainties remain in the quantification of the impact of each anthropogenic forcing. The statistical method is able to reduce the model uncertainty in SST over the warming hole, both over the historical and future periods with a decrease of 65 % in the short term and up to 50 % in the long term. A model evaluation validates the reliability of the obtained projections. In particular, the projections associated with a strong temperature increase over the warming hole are now excluded from the likely range obtained after applying the method.</p>
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spelling doaj.art-4d50c3b4a721445ba254ef87c5c1e59b2023-06-20T10:19:12ZengCopernicus PublicationsEarth System Dynamics2190-49792190-49872023-06-011468569510.5194/esd-14-685-2023Past and future response of the North Atlantic warming hole to anthropogenic forcingS. Qasmi<p>Most of the North Atlantic ocean has warmed over the last decades, except a region located over the subpolar gyre, known as the North Atlantic “warming hole” (WH), where sea surface temperature (SST) has in contrast decreased. Previous assessments have attributed part of this cooling to the anthropogenic forcings (ANT) – aerosols (AER) and greenhouse gases (GHGs) – modulated by decadal internal variability. Here, I use an innovative and proven statistical method which combines climate models and observations to confirm the anthropogenic role in the cooling of the warming hole. The impact of the aerosols is an increase in SST which is opposed to the effect of GHGs. The latter largely contribute to the cooling of the warming hole over the historical period. Yet, large uncertainties remain in the quantification of the impact of each anthropogenic forcing. The statistical method is able to reduce the model uncertainty in SST over the warming hole, both over the historical and future periods with a decrease of 65 % in the short term and up to 50 % in the long term. A model evaluation validates the reliability of the obtained projections. In particular, the projections associated with a strong temperature increase over the warming hole are now excluded from the likely range obtained after applying the method.</p>https://esd.copernicus.org/articles/14/685/2023/esd-14-685-2023.pdf
spellingShingle S. Qasmi
Past and future response of the North Atlantic warming hole to anthropogenic forcing
Earth System Dynamics
title Past and future response of the North Atlantic warming hole to anthropogenic forcing
title_full Past and future response of the North Atlantic warming hole to anthropogenic forcing
title_fullStr Past and future response of the North Atlantic warming hole to anthropogenic forcing
title_full_unstemmed Past and future response of the North Atlantic warming hole to anthropogenic forcing
title_short Past and future response of the North Atlantic warming hole to anthropogenic forcing
title_sort past and future response of the north atlantic warming hole to anthropogenic forcing
url https://esd.copernicus.org/articles/14/685/2023/esd-14-685-2023.pdf
work_keys_str_mv AT sqasmi pastandfutureresponseofthenorthatlanticwarmingholetoanthropogenicforcing