Is the West Antarctic Ice Sheet (WAIS) growing or shrinking? Climate alarmists would have everyone believe that it is rapidly disappearing; while the illuminati—Al Gore and James Hansen—prophetically proclaim that we have but a few short years in which to (1) repent of our profligate usage of fossil fuels, (2) preserve the ice at the planet’s southern pole by curbing our appetite for fossil-fuel energy and stopping global warming, and (3) avoid the catastrophic rise in sea level that would otherwise inundate the world’s coastal lowlands. But are these zealots correct in what they preach? In what follows, we briefly review the findings of several researchers who have focused their attention on the mass balance of the WAIS in an attempt to help reason prevail over rhetoric in this important but contentious war of words.
We conclude our Summary with a brief review of the paper of Krinner et al. (2007), who 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). This work revealed, first of all, that “the simulated present-day surface mass balance is skilful on continental scales,” which gave 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.
The results of this study—based on sea surface boundary conditions taken from IPCC Fourth 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 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 world against such an outcome.
And that seems to be the message of most of the other major studies of the subject as well. We have nothing to fear but fear itself ... plus Al Gore and James Hansen, who seem to be its chief purveyors.
(learn more on this article at icecap.us)