Smith, C.J. orcid.org/0000-0003-0599-4633 and Mathison, C. (2024) How much methane removal is required to avoid overshooting 1.5°C? Environmental Research Letters, 19 (7). 074044. ISSN 1748-9326
Abstract
Methane is the second most important anthropogenic greenhouse gas after carbon dioxide. With an atmospheric lifetime of around a decade, methane mitigation starting immediately has the potential to avoid substantial levels of additional warming by mid-century. In addition to the methane emissions reductions that are necessary to limit warming, we address the question of whether technological methane removal can provide additional benefits by avoiding global mean surface temperatures exceeding 1.5°C above pre-industrial---the high-ambition Paris Agreement climate goal. Using an adaptive emissions methane removal routine in a simple climate model, we successfully limit peak warming to 1.5°C for overshoots of up to around 0.3°C. For substantially higher overshoots, methane removal alone is unable to limit warming to 1.5°C, but in an extreme scenario could limit peak warming by an ensemble median 0.7°C if all atmospheric methane was removed, requiring huge levels of net removal on the order of tens of petagrams cumulatively. The efficacy of methane removal depends on many emergent properties of the climate system, including climate sensitivity, aerosol forcing, and the committed warming after net zero CO$_2$ (zero emissions commitment). To avoid overshooting 1.5°C in the low-overshoot, strong-mitigation SSP1-1.9 scenario, a median cumulative methane removal of 1.2 Pg CH$_4$ is required, though this may be much higher if climate sensitivity is high or the zero emissions commitment is positive, and in these cases may require ongoing methane removal long after peak warming in order to stabilise warming below 1.5°C.
Metadata
Item Type: | Article |
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Authors/Creators: |
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Copyright, Publisher and Additional Information: | © 2024 The Author(s). This is an open access article under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits unrestricted use, distribution and reproduction in any medium, provided the original work is properly cited. |
Keywords: | methane removal, adaptive scenario, climate mitigation |
Dates: |
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Institution: | The University of Leeds |
Academic Units: | The University of Leeds > Faculty of Environment (Leeds) > School of Earth and Environment (Leeds) > Inst for Climate & Atmos Science (ICAS) (Leeds) |
Funding Information: | Funder Grant number NERC (Natural Environment Research Council) NE/T009381/1 EU - European Union 10043512 |
Depositing User: | Symplectic Publications |
Date Deposited: | 21 Jun 2024 10:02 |
Last Modified: | 07 Aug 2024 12:37 |
Status: | Published |
Publisher: | IOP Publishing |
Identification Number: | 10.1088/1748-9326/ad5853 |
Related URLs: | |
Open Archives Initiative ID (OAI ID): | oai:eprints.whiterose.ac.uk:213725 |