Antarctic sea ice projections constrained by historical ice cover and future global temperature change

Holmes, C.R. ORCID: https://orcid.org/0000-0002-3134-555X; Bracegirdle, T.J. ORCID: https://orcid.org/0000-0002-8868-4739; Holland, P.R. ORCID: https://orcid.org/0000-0001-8370-289X. 2022 Antarctic sea ice projections constrained by historical ice cover and future global temperature change. Geophysical Research Letters, 49 (10), e2021GL097413. 10, pp. https://doi.org/10.1029/2021GL097413

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Abstract/Summary

There is low confidence in projections of Antarctic sea ice area (SIA), due to deficiencies in climate model sea ice processes. Ensemble regression techniques can help to reduce this uncertainty. We investigate relationships between SIA climatology and 21st century change in the CMIP6 multi-model ensemble. In summer, under a strong forcing scenario, each model loses the majority of its sea ice. Therefore, models with greater historical SIA exhibit greater reductions, so the observed climatology of SIA strongly constrains projections. Ensemble spread in historical summer SIA is smaller than in CMIP5, and CMIP6 gives a more robust constraint on future SIA. In winter, by 2100 under a strong forcing scenario, 40% of SIA disappears on average, and ensemble spread in historical mean SIA explains approximately half the spread in projected change. A greater winter ice loss in CMIP6 than CMIP5 is explained by the higher climate sensitivities of some CMIP6 models.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	https://doi.org/10.1029/2021GL097413
ISSN:	0094-8276
Additional Keywords:	sea ice, emergent constraints, climate projections, uncertainty, CMIP5, CMIP6
Date made live:	09 May 2022 09:05 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/532593

Item Type:

Publication - Article

Digital Object Identifier (DOI):

https://doi.org/10.1029/2021GL097413

ISSN:

0094-8276

Additional Keywords:

sea ice, emergent constraints, climate projections, uncertainty, CMIP5, CMIP6

Date made live:

09 May 2022 09:05 +0 (UTC)

URI:

https://nora.nerc.ac.uk/id/eprint/532593