Interactions between increasing CO2 and Antarctic melt rates

Mackie, Shona, Smith, Inga J., Stevens, David P., Ridley, Jeff K. and Langhorne, Patricia J. (2020) Interactions between increasing CO2 and Antarctic melt rates. Journal of Climate, 33 (20). 8939–8956. ISSN 0894-8755

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Abstract

Meltwater from the Antarctic ice sheet is expected to increase the sea ice extent. However, such an expansion may be moderated by sea ice decline associated with global warming. Here we investigate the relative balance of these two processes through experiments using HadGEM3-GC3.1 and compare these to two standard idealized CMIP6 experiments. Our results show that the decline in sea ice projected under scenarios of increasing CO 2 may be inhibited by simultaneously increasing melt fluxes. We find that Antarctic Bottom Water formation, projected to decline as CO 2 increases, is likely to decline further with an increasing meltwater flux. In our simulations, the response of the westerly wind jet to increasing CO 2 is enhanced when the meltwater flux increases, resulting in a stronger peak wind stress than is found when either CO 2 or melt rates increase exclusively. We find that the sensitivity of the Antarctic Circumpolar Current to increasing melt fluxes in the Southern Ocean is countered by increasing CO 2, removing or reducing a feedback mechanism that may otherwise allow more heat to be transported to the polar regions and drive increasing ice shelf melt rates. The insights presented here and in a companion paper (which focuses on the effect of increasing melt fluxes under preindustrial forcings) provide insights helpful to the interpretation of both future climate projections and sensitivity studies into the effect of increasing melt fluxes from the Antarctic ice sheet when different forcing scenarios are used.

Item Type: Article
Additional Information: The manuscript is 38.5MB and the upload fails. I've omitted the bulk of the figures to get something I can upload.
Uncontrolled Keywords: antarctica,climate models,coupled models,sea ice,southern ocean,atmospheric science ,/dk/atira/pure/subjectarea/asjc/1900/1902
Faculty \ School: Faculty of Science > School of Mathematics
Related URLs:
Depositing User: LivePure Connector
Date Deposited: 24 Jul 2020 23:45
Last Modified: 01 Aug 2021 00:07
URI: https://ueaeprints.uea.ac.uk/id/eprint/76278
DOI: 10.1175/JCLI-D-19-0882.1

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