Competition between global warming and an abrupt collapse of the AMOC in Earth’s energy imbalance
Competition between global warming and an abrupt collapse of the AMOC in Earth’s energy imbalance
A collapse of the Atlantic Meridional Overturning Circulation (AMOC) leads to global cooling through fast feedbacks that selectively amplify the response in the Northern Hemisphere (NH). How such cooling competes with global warming has long been a topic for speculation, but was never addressed using a climate model. Here it is shown that global cooling due to a collapsing AMOC obliterates global warming for a period of 15–20 years. Thereafter, the global mean temperature trend is reversed and becomes similar to a simulation without an AMOC collapse. The resulting surface warming hiatus lasts for 40–50 years. Global warming and AMOC-induced NH cooling are governed by similar feedbacks, giving rise to a global net radiative imbalance of similar sign, although the former is associated with surface warming, the latter with cooling. Their footprints in outgoing longwave and absorbed shortwave radiation are very distinct, making attribution possible.
Drijfhout, Sybren
a5c76079-179b-490c-93fe-fc0391aacf13
6 October 2015
Drijfhout, Sybren
a5c76079-179b-490c-93fe-fc0391aacf13
Drijfhout, Sybren
(2015)
Competition between global warming and an abrupt collapse of the AMOC in Earth’s energy imbalance.
Scientific Reports, 5, [14877].
(doi:10.1038/srep14877).
Abstract
A collapse of the Atlantic Meridional Overturning Circulation (AMOC) leads to global cooling through fast feedbacks that selectively amplify the response in the Northern Hemisphere (NH). How such cooling competes with global warming has long been a topic for speculation, but was never addressed using a climate model. Here it is shown that global cooling due to a collapsing AMOC obliterates global warming for a period of 15–20 years. Thereafter, the global mean temperature trend is reversed and becomes similar to a simulation without an AMOC collapse. The resulting surface warming hiatus lasts for 40–50 years. Global warming and AMOC-induced NH cooling are governed by similar feedbacks, giving rise to a global net radiative imbalance of similar sign, although the former is associated with surface warming, the latter with cooling. Their footprints in outgoing longwave and absorbed shortwave radiation are very distinct, making attribution possible.
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srep14877.pdf
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Accepted/In Press date: 10 September 2015
Published date: 6 October 2015
Organisations:
Physical Oceanography
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Local EPrints ID: 383869
URI: http://eprints.soton.ac.uk/id/eprint/383869
PURE UUID: 0b05be95-9310-4660-ae13-cd164b2f8844
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Date deposited: 10 Nov 2015 14:35
Last modified: 15 Mar 2024 03:44
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