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Effect of CO2-Induced Global Warming on Antarctic Surface Mass Balance a Hundred Years Hence
Reference
Krinner, G., Magand, O., Simmonds, I., Genthon, C. and Dufresne, J.-L. 2007. Simulated Antarctic precipitation and surface mass balance at the end of the twentieth and twenty-first centuries. Climate Dynamics 28: 215-230.

What was done
The authors used the LMDZ4 atmospheric general circulation model (Hourdin et al., 2006) to simulate Antarctic climate for the periods 1981-2000 (to test the model's ability to adequately simulate present conditions) and 2081-2100 (to see what the future might hold for the mass balance of the Antarctic Ice Sheet and its impact on global sea level).

What was learned
Krinner et al. report, first of all, that "the simulated present-day surface mass balance is skilful on continental scales," giving them confidence that their results for the end of the 21st century would be reasonably skilful as well. Of that latter period a full century from now, they determined that "the simulated Antarctic surface mass balance increases by 32 mm water equivalent per year," which corresponds "to a sea level decrease of 1.2 mm per year by the end of the twenty-first century," which would in turn "lead to a cumulated sea level decrease of about 6 cm." This result, in their words, occurs because the simulated temperature increase "leads to an increased moisture transport towards the interior of the continent because of the higher moisture holding capacity of warmer air," where the extra moisture falls as precipitation, causing the continent's ice sheet to grow.

What it means
The results of this study - based on sea surface boundary conditions taken from IPCC 4th assessment report simulations (Dufresne et al., 2005) that were carried out with the IPSL-CM4 coupled atmosphere-ocean general circulation model (Marti et al., 2005), of which the LMDZ4 model is the atmospheric component - argue strongly against climate-alarmist predictions of future catastrophic sea level rise due to the mass wastage of the Antarctic Ice Sheet caused by CO2-induced global warming. In fact, they suggest just the opposite, i.e., that CO2-induced global warming would tend to buffer the planet against such an outcome.

References
Dufresne, J.L., Quaas, J., Boucher, O., Denvil, S. and Fairhead, L. 2005. Contrasts in the effects on climate of anthropogenic sulfate aerosols between the 20th and the 21st century. Geophysical Research Letters 32: 10.1029/2005GL023619.

Hourdin, F., Musat, I., Bony, S., Braconnot, P., Codron, F., Dufresne, J.L., Fairhead, L., Filiberti, M.A., Friedlingstein, P., Grandpeix, J.Y., Krinner, G., Le Van, P., Li, Z.X. and Lott, F. 2006. The LMDZ4 general circulation model: climate performance and sensitivity to parameterized physics with emphasis on tropical convection. Climate Dynamics 27: 787-813.

Marti, O., Braconnot, P., Bellier, J., Benshila, R., Bony, S., Brockmann, P., Cadule, P., Caubel, A., Denvil, S., Dufresne, J.L., Fairhead, L., Filiberti, M.A., Foujols, M.A., Fichefet, T., Friedlingstein, P., Grandpeix, J.Y., Hourdin, F., Krinner, G., Levy, C., Madec, G., Musat, I., de Noblet-Ducoudre, N., Polcher, J. and Talandier, C. 2005. The new IPSL climate system model: IPSL-CM4. Note du Pole de Modelisation n. 26, IPSL, ISSN 1288-1619.

Reviewed 31 January 2007