Global sea level could rise by 6 feet by 2100, double the previous estimates / Boing Boing

A new study on melting polar ice warns that sea level could rise by nearly six feet by 2100, an estimate two times higher than expected.

The newly modeled sea level rise would devastate parts of the world's major cities and displace hundreds of millions of people.

The study was published Monday in the Proceedings of the National Academy of Sciences [PNAS] newspaper [Link].

Here is an exerpt:

The future rise in sea level seriously threatens the viability of coastal communities, but remains difficult to project with the help of deterministic modeling approaches. Nevertheless, adaptation strategies urgently require a quantification of uncertainties regarding future SLRs, especially high-end estimates. The structured expert judgment (SEJ) has proven to be a valuable approach for similar problems. Our results, using SEJ, produce probability distributions with long upper tails influenced by interdependencies between processes and ice layers. We find that an overall total of SLR greater than 2m by 2100 lies within the 90% uncertainty range for a high emissions scenario. This is more than double the maximum value indicated by the Intergovernmental Panel on Climate Change in the Fifth Assessment Report.

Despite considerable progress in understanding the processes, numerical modeling and the number of observations on the contributions of the ice cap to the average sea level rise since the fifth assessment report ( RE5) of the Intergovernmental Panel on Climate Change, there are still significant limitations on the capacity of ice sheet models. As a result, the potential contributions of ice sheets remain the greatest source of uncertainty in the projection of future SLRs. Here we report the results of a structured judgmental study of experts, using unique techniques to model the correlations between inter and intra-ice slick processes and their tail dependencies. We note that since AR5, the uncertainty of the experts has increased, particularly because of the uncertain effects of ice dynamics.

Clara Nugent, reporting for Time on the new study:

The upper limit of sea level rise by 2100 has already been estimated between 1.7 and 3.2 feet. – the range indicated in the Fifth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC), the main international body assessing climate change, in 2013. But many scientists believe that it was a conservative estimate. The melting rate of glaciers in Greenland and Antarctica is accelerating, and the report argues that current forecasting models do not take into account significant uncertainties as to how melting glaciers could affect the rise in the level of glaciers. of the sea.

To better understand, an international group of researchers developed a "structured judgmental study of experts," which allowed experts to understand what is happening to glaciers to predict a wider range of possibilities than those envisaged in the IPCC report.

Read the study:
The contributions of the ice sheets to the future sea level rise from a judgment of structured experts
Jonathan L. Bamber, Michael Oppenheimer, Robert E. Kopp, Willy P. Aspinall and Roger M. Cooke

[PHOTO: NASA.GOV]

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