Scientists at the University of Wisconsin-Madison have reconstructed events at the end of the last ice age to produce a theory that sea levels could rise at a rate of over 1m per century.
The researchers found that the Laurentide ice sheet, which covered most of North America between 95,000 and 7000 years ago, disintegrated rapidly.
The project, reported in the journal Geoscience, studied beryllium isotopes in rocks, and dated boulders and fossils left as the ice sheet retreated to work out how the edges of the two last portions of the ice sheet retreated, and calculated the volume of water that would have been released in each of the two final rapid melting stages.
Their conclusion was that sea levels would have risen by 1.3m per century in the earlier melt, and 0.7m per century in the final phase. A computer model used to forecast future climate change confirmed the results.
Gavin Schmidt of the NASA Goddard Institute for Space Studies, which collaborated with Wisconsin-Madison on the study, warned: ‘The forces that led to the demise of the Laurentide ice sheet in a very rapid way are comparable to the forces the same computer models predict we will experience this century if we do not rapidly curb greenhouse gas emissions.’
If the estimates are correct, they suggest the IPPC’s 2007 predictions of a sea level rise of between 180mm and 590mm by 2100 may be extremely conservative. The findings suggest that large ice sheets can disintegrate with extreme rapidity, backing previous claims that a ‘tipping point’ could be reached beyond which the world’s ice sheets will disappear swiftly.
The researchers suggested that the Greenland ice sheet could retreat in a similarly rapid fashion.
IWA Publishing – GLOBAL: Research into Ice Age retreat predicts higher sea level rises
