What will be the contribution to sea level rise of the ice sheets in Greenland and Antarctica over the coming century?

Sea level change is one the most outstanding issue in Earth System Science in terms of scientific and societal impact. The largest uncertainty in sea level projections is the rate of melting of ice sheets into the ocean in a warming climate. We are far from being able to make predictions of ice sheet evolution. Progress is urgently needed.

3 comments

1. Alastair says:

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   No consideration seems to have been given to the effects of the disappearance of the Arctic sea ice, possibly within the next twenty years by 2030, on the Greenland ice sheet. If it melts rapidly will the consequent rise in sea level destabilise the Antarctic ice shelves?
2. sidd says:

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   Mr. Rignot:

   If you are Eric Rignot, let me thank you for your research over the years. I always look forward to reading your papers.

   My comment, which I also submitted at realclimate, is the following:

   I notice a paper by Siddall et al., Nature Geoscience, 26 July 2009.Their model predicts between 7 and 82 cm of sea level rise by 2100. Equilibrium sea level rise is expressed as having an inverse sinh relationship to temperature change over the last 22KYr, and instantaneous sea level rise is governed by a constant, tau, which gives a best fit result between 2.4 and 3.4 Kyr. Can this 3KYr timescale to be reconciled with Andrill data indicating WAIS collapse on the timescale of 1KYr ?

   They point out that the albedo, altitude, and isostatic rebound feedbacks accelerate deglagiation. They fit the data over 22KYr before present. Could it be as Hansen argues, they are modelling the external forcing timescales rather than the internal timescales for ice sheet disintegration ? Or is there something like the Weertman instability shortening the timescale for WAIS collapse in the Andrill data, which is not present in the periods they model?
3. africain says:

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   The rate of melting of ice sheets is uncertain, but the actual melting is larger than most predictions, including the ice cap of Kerguelen islands in the southern hemisphere.
   The sea level is rising. In some low ground islands of the Pacific ocean, the population had to be transferred to islands with a slightly more elevated ground. Some Bangladesh fields are too full of salt for being used anymore. Urgent action is needed for decreasing the warming responsible for the melting.