Journal cover Journal topic
The Cryosphere An interactive open-access journal of the European Geosciences Union
The Cryosphere, 6, 193-198, 2012
© Author(s) 2012. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
13 Feb 2012
How reversible is sea ice loss?
J. K. Ridley, J. A. Lowe, and H. T. Hewitt Met Office, FitzRoy Road, Exeter, EX1 3PB, UK
Abstract. It is well accepted that increasing atmospheric CO2 results in global warming, leading to a decline in polar sea ice area. Here, the specific question of whether there is a tipping point in the sea ice cover is investigated. The global climate model HadCM3 is used to map the trajectory of sea ice area under idealised scenarios. The atmospheric CO2 is first ramped up to four times pre-industrial levels (4 × CO2), then ramped down to pre-industrial levels. We also examine the impact of stabilising climate at 4 × CO2 prior to ramping CO2 down to pre-industrial levels. Against global mean temperature, Arctic sea ice area is reversible, while the Antarctic sea ice shows some asymmetric behaviour – its rate of change slower, with falling temperatures, than its rate of change with rising temperatures. However, we show that the asymmetric behaviour is driven by hemispherical differences in temperature change between transient and stabilisation periods. We find no irreversible behaviour in the sea ice cover.

Citation: Ridley, J. K., Lowe, J. A., and Hewitt, H. T.: How reversible is sea ice loss?, The Cryosphere, 6, 193-198, doi:10.5194/tc-6-193-2012, 2012.
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