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Simulating the climate response to atmospheric oxygen variability in the Phanerozoic: a focus on the Holocene, Cretaceous and Permian

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Simulating the climate response to atmospheric oxygen variability in the Phanerozoic : a focus on the Holocene, Cretaceous and Permian. / Wade, David C.; Luke Abraham, Nathan; Farnsworth, Alexander; Valdes, Paul J.; Bragg, Fran; Archibald, Alexander T.

In: Climate of the Past, Vol. 15, 05.08.2019, p. 1463-1483.

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@article{19581e33a1264289aa82a5ba1fa8b0bb,
title = "Simulating the climate response to atmospheric oxygen variability in the Phanerozoic: a focus on the Holocene, Cretaceous and Permian",
abstract = "The amount of dioxygen (O-2) in the atmosphere may have varied from as little as 5{\%} to as much as 35{\%} during the Phanerozoic eon (54 Ma-present). These changes in the amount of O-2 are large enough to have led to changes in atmospheric mass, which may alter the radiative budget of the atmosphere, leading to this mechanism being invoked to explain discrepancies between climate model simulations and proxy reconstructions of past climates. Here, we present the first fully 3-D numerical model simulations to investigate the climate impacts of changes in O2 under different climate states using the coupled atmosphere-ocean Hadley Centre Global Environmental Model version 3 (HadGEM3-AO) and Hadley Centre Coupled Model version 3 (HadCM3-BL) models. We show that simulations with an increase in O-2 content result in increased global-mean surface air temperature under conditions of a pre-industrial Holocene climate state, in agreement with idealised 1-D and 2-D modelling studies. We demonstrate the mechanism behind the warming is complex and involves a trade-off between a number of factors. Increasing atmospheric O-2 leads to a reduction in incident shortwave radiation at the Earth's surface due to Rayleigh scattering, a cooling effect. However, there is a competing warming effect due to an increase in the pressure broadening of greenhouse gas absorption lines and dynamical feedbacks, which alter the meridional heat transport of the ocean, warming polar regions and cooling tropical regions. Case studies from past climates are investigated using HadCM3-BL and show that, in the warmest climate states in the Maastrichtian (72.1-66.0 Ma), increasing oxygen may lead to a temperature decrease, as the equilibrium climate sensitivity is lower. For the Asselian (298.9-295.0 Ma), increasing oxygen content leads to a warmer global-mean surface temperature and reduced carbon storage on land, suggesting that high oxygen content may have been a contributing factor in preventing a {"}Snowball Earth{"} during this period of the early Permian. These climate model simulations reconcile the surface temperature response to oxygen content changes across the hierarchy of model complexity and highlight the broad range of Earth system feedbacks that need to be accounted for when considering the climate response to changes in atmospheric oxygen content.",
keywords = "co2 concentrations isotope evidence coupled model carbon o-2 greenhouse evolution impact chemistry plants",
author = "Wade, {David C.} and {Luke Abraham}, Nathan and Alexander Farnsworth and Valdes, {Paul J.} and Fran Bragg and Archibald, {Alexander T.}",
year = "2019",
month = "8",
day = "5",
doi = "10.5194/cp-15-1463-2019",
language = "English",
volume = "15",
pages = "1463--1483",
journal = "Climate of the Past",
issn = "1814-9324",
publisher = "Copernicus GmbH",

}

RIS - suitable for import to EndNote

TY - JOUR

T1 - Simulating the climate response to atmospheric oxygen variability in the Phanerozoic

T2 - a focus on the Holocene, Cretaceous and Permian

AU - Wade, David C.

AU - Luke Abraham, Nathan

AU - Farnsworth, Alexander

AU - Valdes, Paul J.

AU - Bragg, Fran

AU - Archibald, Alexander T.

PY - 2019/8/5

Y1 - 2019/8/5

N2 - The amount of dioxygen (O-2) in the atmosphere may have varied from as little as 5% to as much as 35% during the Phanerozoic eon (54 Ma-present). These changes in the amount of O-2 are large enough to have led to changes in atmospheric mass, which may alter the radiative budget of the atmosphere, leading to this mechanism being invoked to explain discrepancies between climate model simulations and proxy reconstructions of past climates. Here, we present the first fully 3-D numerical model simulations to investigate the climate impacts of changes in O2 under different climate states using the coupled atmosphere-ocean Hadley Centre Global Environmental Model version 3 (HadGEM3-AO) and Hadley Centre Coupled Model version 3 (HadCM3-BL) models. We show that simulations with an increase in O-2 content result in increased global-mean surface air temperature under conditions of a pre-industrial Holocene climate state, in agreement with idealised 1-D and 2-D modelling studies. We demonstrate the mechanism behind the warming is complex and involves a trade-off between a number of factors. Increasing atmospheric O-2 leads to a reduction in incident shortwave radiation at the Earth's surface due to Rayleigh scattering, a cooling effect. However, there is a competing warming effect due to an increase in the pressure broadening of greenhouse gas absorption lines and dynamical feedbacks, which alter the meridional heat transport of the ocean, warming polar regions and cooling tropical regions. Case studies from past climates are investigated using HadCM3-BL and show that, in the warmest climate states in the Maastrichtian (72.1-66.0 Ma), increasing oxygen may lead to a temperature decrease, as the equilibrium climate sensitivity is lower. For the Asselian (298.9-295.0 Ma), increasing oxygen content leads to a warmer global-mean surface temperature and reduced carbon storage on land, suggesting that high oxygen content may have been a contributing factor in preventing a "Snowball Earth" during this period of the early Permian. These climate model simulations reconcile the surface temperature response to oxygen content changes across the hierarchy of model complexity and highlight the broad range of Earth system feedbacks that need to be accounted for when considering the climate response to changes in atmospheric oxygen content.

AB - The amount of dioxygen (O-2) in the atmosphere may have varied from as little as 5% to as much as 35% during the Phanerozoic eon (54 Ma-present). These changes in the amount of O-2 are large enough to have led to changes in atmospheric mass, which may alter the radiative budget of the atmosphere, leading to this mechanism being invoked to explain discrepancies between climate model simulations and proxy reconstructions of past climates. Here, we present the first fully 3-D numerical model simulations to investigate the climate impacts of changes in O2 under different climate states using the coupled atmosphere-ocean Hadley Centre Global Environmental Model version 3 (HadGEM3-AO) and Hadley Centre Coupled Model version 3 (HadCM3-BL) models. We show that simulations with an increase in O-2 content result in increased global-mean surface air temperature under conditions of a pre-industrial Holocene climate state, in agreement with idealised 1-D and 2-D modelling studies. We demonstrate the mechanism behind the warming is complex and involves a trade-off between a number of factors. Increasing atmospheric O-2 leads to a reduction in incident shortwave radiation at the Earth's surface due to Rayleigh scattering, a cooling effect. However, there is a competing warming effect due to an increase in the pressure broadening of greenhouse gas absorption lines and dynamical feedbacks, which alter the meridional heat transport of the ocean, warming polar regions and cooling tropical regions. Case studies from past climates are investigated using HadCM3-BL and show that, in the warmest climate states in the Maastrichtian (72.1-66.0 Ma), increasing oxygen may lead to a temperature decrease, as the equilibrium climate sensitivity is lower. For the Asselian (298.9-295.0 Ma), increasing oxygen content leads to a warmer global-mean surface temperature and reduced carbon storage on land, suggesting that high oxygen content may have been a contributing factor in preventing a "Snowball Earth" during this period of the early Permian. These climate model simulations reconcile the surface temperature response to oxygen content changes across the hierarchy of model complexity and highlight the broad range of Earth system feedbacks that need to be accounted for when considering the climate response to changes in atmospheric oxygen content.

KW - co2 concentrations isotope evidence coupled model carbon o-2 greenhouse evolution impact chemistry plants

UR - http://www.scopus.com/inward/record.url?scp=85073896876&partnerID=8YFLogxK

U2 - 10.5194/cp-15-1463-2019

DO - 10.5194/cp-15-1463-2019

M3 - Article

VL - 15

SP - 1463

EP - 1483

JO - Climate of the Past

JF - Climate of the Past

SN - 1814-9324

ER -