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

Alexander Farnsworth; Dan Lunt; C O'Brien; Gavin Foster; Gordon Inglis; Paul Markwick; Rich Pancost; Stuart A. Robinson

doi:10.1029/2019GL083574

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

Alexander Farnsworth, Dan Lunt, C O'Brien, Gavin Foster, Gordon Inglis, Paul Markwick, Rich Pancost, Stuart A. Robinson

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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 ∼3.5-5.5◦C through this time. These variations can be explained as a non-linear 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.

Original language	English
Number of pages	10
Journal	Geophysical Research Letters
Early online date	20 Aug 2019
DOIs	https://doi.org/10.1029/2019GL083574
Publication status	E-pub ahead of print - 20 Aug 2019

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This is the author accepted manuscript (AAM). The final published version (version of record) is available online via American Geophysical Union at https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GL083574 . Please refer to any applicable terms of use of the publisher.
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Full-text PDF (final published version)
This is the final published version of the article (version of record). It first appeared online via American Geophysical Union at https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GL083574 . Please refer to any applicable terms of use of the publisher.
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SWEET NERC Large Grant
Lunt, D. (Principal Investigator)
1/10/17 → 30/09/23
Project: Research
Cretaceous-Paleocene-Eocene Climate and Climate Sensitivity
Lunt, D. (Principal Investigator)
1/01/14 → 1/01/17
Project: Research

HPC (High Performance Computing) and HTC (High Throughput Computing) Facilities
Alam, S. R. (Manager), Eccleston, P. E. (Other), Williams, D. A. G. (Manager) & Atack, S. H. (Other)
Facility/equipment: Facility

Cite this

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title = "Climate sensitivity on geological timescales controlled by nonlinear feedbacks and ocean circulation",

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 showthat climate sensitivity to CO2 doubling varies between ∼3.5-5.5◦C through this time. These variations can be explained as a non-linear 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.",

author = "Alexander Farnsworth and Dan Lunt and C O'Brien and Gavin Foster and Gordon Inglis and Paul Markwick and Rich Pancost and Robinson, {Stuart A.}",

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T1 - Climate sensitivity on geological timescales controlled by nonlinear feedbacks and ocean circulation

AU - Farnsworth, Alexander

AU - Lunt, Dan

AU - O'Brien, C

AU - Foster, Gavin

AU - Inglis, Gordon

AU - Markwick, Paul

AU - Pancost, Rich

AU - Robinson, Stuart A.

PY - 2019/8/20

Y1 - 2019/8/20

N2 - 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 showthat climate sensitivity to CO2 doubling varies between ∼3.5-5.5◦C through this time. These variations can be explained as a non-linear 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.

AB - 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 showthat climate sensitivity to CO2 doubling varies between ∼3.5-5.5◦C through this time. These variations can be explained as a non-linear 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.

U2 - 10.1029/2019GL083574

DO - 10.1029/2019GL083574

M3 - Article (Academic Journal)

SN - 0094-8276

JO - Geophysical Research Letters

JF - Geophysical Research Letters

ER -

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

Abstract

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Projects

SWEET NERC Large Grant

Cretaceous-Paleocene-Eocene Climate and Climate Sensitivity

Equipment

HPC (High Performance Computing) and HTC (High Throughput Computing) Facilities

Cite this