Wednesday, July 29, 2009

New predictions for sea level rise

University of Bristol: Fossil coral data and temperature records derived from ice-core measurements have been used to place better constraints on future sea level rise, and to test sea level projections. The results are published today in Nature Geoscience and predict that the amount of sea level rise by the end of this century will be between 7- 82 cm – depending on the amount of warming that occurs – a figure similar to that projected by the IPCC report of 2007.

Placing limits on the amount of sea level rise over the next century is one of the most pressing challenges for climate scientists. The uncertainties around different methods to achieve accurate predictions are highly contentious because the response of the Greenland and Antarctic ice sheets to warming is not well understood.

Dr Mark Siddall from the Earth Sciences Department at the University of Bristol, together with colleagues from Switzerland and the US, used fossil coral data and temperature records derived from ice-core measurements to reconstruct sea level fluctuations in response to changing climate for the past 22,000 years, a period that covers the transition from glacial maximum to the warm Holocene interglacial period.

By considering how sea level has responded to temperature since the end of the last glacial period, Siddall and colleagues predict that the amount of sea level rise by the end of this century will be similar to that projected by the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC).

Dr Siddall said: “Given that the two approaches are entirely independent of each other, this result strengthens the confidence with which one may interpret the IPCC results. It is of vital importance that this semi-empirical result, based on a wealth of data from fossil corals, converges so closely with the IPCC estimates….

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