In 2006, in his famous documentary, An Inconvenient Truth, Al Gore claimed sea levels would rise by 20 feet (six metre).
The Intergovernmental Panel on Climate Change (IPCC) is more conservative, suggesting a rise of no more than 0.60m by 2099 in its 2007 report.
But in March last year a fellow called Robyn Williams, who has a monopoly on the broadcasting of science programs on Australia’s ABC, scared us with claims sea levels could rise by over 100 metres in the next century because of increases in the rate of ice melt in Greenland and western Antarctica.
A study of sea level rise from ice melt in Greenland and western Antarctica has just been published in Science and concludes that a rise of 0.8 metres is possible by 2100, but MORE** than 2 metres “physically untenable”.
Research scientists W.T. Pfeffer, J.T. Harper and S.O’Neel calculated how much ice and water would need to be lost from Greenland and Antarctica for a two metre rise, then how fast contributing glaciers would need to move in order to dump that much ice, and concluded that a two meter rise in sea level by 2100 would require significantly faster ice velocities than had ever been reported before.
Of course at the moment it is unclear how much warming is actually occurring at the Antarctic, with some suggesting a general trend of cooling there in accordance with the recent global trend. But if the melting starts again at the Antarctic, and continues in the Arctic, it is perhaps reassuring to know, that even under a worst case scenario sea levels should not rise by more than 0.8 metres in the next 100 years.
** I’ve added the word ‘more’ included to the title of this piece as Pfeffer et al claim it is physically untenable to suggest a rise of more than 2 metres – not up to 2 metres as I suggested in the original post. Thanks to Luke and others for pointing this error out.
Kinematic Constraints on Glacier Contributions to 21st-Century Sea-Level Rise, W. T. Pfeffer, J. T. Harper, S. O’Neel, Science, 5 September 2008:
Vol. 321. no. 5894, pp. 1340 – 1343. DOI: 10.1126/science.1159099