The University of Southampton
University of Southampton Institutional Repository

Climate sensitivity on geological timescales controlled by nonlinear feedbacks and ocean circulation

Climate sensitivity on geological timescales controlled by nonlinear feedbacks and ocean circulation
Climate sensitivity on geological timescales controlled by nonlinear feedbacks and ocean circulation

Climate sensitivity is a key metric used to assess the magnitude of global warming given increased CO2 concentrations. The geological past can provide insights into climate sensitivity; however, on timescales of millions of years, factors other than CO2 can drive climate, including paleogeographic forcing and solar luminosity. Here, through an ensemble of climate model simulations covering the period 150–35 million years ago, we show that climate sensitivity to CO2 doubling varies between ∼3.5 and 5.5 °C through this time. These variations can be explained as a nonlinear response to solar luminosity, evolving surface albedo due to changes in ocean area, and changes in ocean circulation. The work shows that the modern climate sensitivity is relatively low in the context of the geological record, as a result of relatively weak feedbacks due to a relatively low CO2 baseline, and the presence of ice and relatively small ocean area in the modern continental configuration.

climate sensitivity, paleoclimate modeling
0094-8276
9880-9889
Farnsworth, A.
2be2b60e-d93a-4e07-bcf9-0147ad328e7a
Lunt, D.J.
931ecfb5-1f50-412c-8f01-a46d69b1f82f
O'Brien, C.L.
a9bb3762-28c3-408f-ac26-2ad16f327f47
Foster, G.L.
fbaa7255-7267-4443-a55e-e2a791213022
Inglis, G.N.
1651196d-916c-43cb-b5a0-9b3ecaf5d664
Markwick, P.
fb6da003-9a49-4b6d-b6d7-29c15c3c9226
Pancost, R.D.
5914e19e-7777-4304-9fd8-86e2e9cfe8a1
Robinson, S.A.
641771c2-c717-4a21-86d1-7eaa1f2ef23b
Farnsworth, A.
2be2b60e-d93a-4e07-bcf9-0147ad328e7a
Lunt, D.J.
931ecfb5-1f50-412c-8f01-a46d69b1f82f
O'Brien, C.L.
a9bb3762-28c3-408f-ac26-2ad16f327f47
Foster, G.L.
fbaa7255-7267-4443-a55e-e2a791213022
Inglis, G.N.
1651196d-916c-43cb-b5a0-9b3ecaf5d664
Markwick, P.
fb6da003-9a49-4b6d-b6d7-29c15c3c9226
Pancost, R.D.
5914e19e-7777-4304-9fd8-86e2e9cfe8a1
Robinson, S.A.
641771c2-c717-4a21-86d1-7eaa1f2ef23b

Farnsworth, A., Lunt, D.J., O'Brien, C.L., Foster, G.L., Inglis, G.N., Markwick, P., Pancost, R.D. and Robinson, S.A. (2019) Climate sensitivity on geological timescales controlled by nonlinear feedbacks and ocean circulation. Geophysical Research Letters, 46 (16), 9880-9889. (doi:10.1029/2019GL083574).

Record type: Article

Abstract

Climate sensitivity is a key metric used to assess the magnitude of global warming given increased CO2 concentrations. The geological past can provide insights into climate sensitivity; however, on timescales of millions of years, factors other than CO2 can drive climate, including paleogeographic forcing and solar luminosity. Here, through an ensemble of climate model simulations covering the period 150–35 million years ago, we show that climate sensitivity to CO2 doubling varies between ∼3.5 and 5.5 °C through this time. These variations can be explained as a nonlinear response to solar luminosity, evolving surface albedo due to changes in ocean area, and changes in ocean circulation. The work shows that the modern climate sensitivity is relatively low in the context of the geological record, as a result of relatively weak feedbacks due to a relatively low CO2 baseline, and the presence of ice and relatively small ocean area in the modern continental configuration.

Text
Farnsworth_et_al-2019-Geophysical_Research_Letters - Version of Record
Available under License Other.
Download (1MB)

More information

Accepted/In Press date: 9 July 2019
e-pub ahead of print date: 29 July 2019
Published date: 28 August 2019
Keywords: climate sensitivity, paleoclimate modeling

Identifiers

Local EPrints ID: 435413
URI: http://eprints.soton.ac.uk/id/eprint/435413
ISSN: 0094-8276
PURE UUID: 301de1c4-af16-4263-b9ba-ed297189701c
ORCID for G.L. Foster: ORCID iD orcid.org/0000-0003-3688-9668
ORCID for G.N. Inglis: ORCID iD orcid.org/0000-0002-0032-4668

Catalogue record

Date deposited: 06 Nov 2019 17:30
Last modified: 18 Mar 2024 05:25

Export record

Altmetrics

Contributors

Author: A. Farnsworth
Author: D.J. Lunt
Author: C.L. O'Brien
Author: G.L. Foster ORCID iD
Author: G.N. Inglis ORCID iD
Author: P. Markwick
Author: R.D. Pancost
Author: S.A. Robinson

Download statistics

Downloads from ePrints over the past year. Other digital versions may also be available to download e.g. from the publisher's website.

View more statistics

Atom RSS 1.0 RSS 2.0

Contact ePrints Soton: eprints@soton.ac.uk

ePrints Soton supports OAI 2.0 with a base URL of http://eprints.soton.ac.uk/cgi/oai2

This repository has been built using EPrints software, developed at the University of Southampton, but available to everyone to use.

We use cookies to ensure that we give you the best experience on our website. If you continue without changing your settings, we will assume that you are happy to receive cookies on the University of Southampton website.

×