January 18, 2006

Not As Bad As We Thought!

A couple of weeks ago we wrote a cute little piece titled “Proving Science Bias” that looked into the deluge of news stories on global warming and its impacts that were released on a single day last December when both the COP-11 meeting was going on in Montreal and the fall meeting of American Geophysical Union (AGU) was taking place in San Francisco. Of the 15 different findings that were released and covered by the press on December 7, 2005 about global warming, 14 of them were reporting that things were “worse than we thought” and only one of them concluded that things weren’t going to be as bad as originally forecast. Given an unbiased prediction, there should be a 50-50 chance that things turned out either worse or better than expected. Under such a scenario, there is only a 1-in-2,000 chance that 14 things out of 15 would be worse. But that’s what happened. So, either the original forecasts were not unbiased, a rare event did indeed occur, or, more likely, the interpretation and reporting went a bit over the top—that is, the press (and to some degree the researchers themselves) only like to hype the more extreme results.

A report in the January 19th issue of Nature magazine will help test this theory. Researchers Sarah Raper and Roger Braithwaite have published a paper titled “Low sea level rise projections from mountain glaciers and icecaps under global warming.” Using a more realistic glacier shrinkage model than the one used by the IPCC in its 2001 Third Assessment Report (TAR)—one that allows glaciers to reach a new mass balance state under warming conditions rather than having to completely melt away—Raper and Braithwaite find that the contribution from sea level rise from the melting of glaciers and icecaps is only going to be about half as much as originally projected in the IPCC TAR under one of their mid-range warming scenarios (SRES A1B). Admittedly, the additional input of water from shrinking icecaps and glaciers is not a major contributor to the total sea level rise—together they contribute about 27% (or 4.2 in.) to the overall total of 15.2 in. projected by the IPCC to accompany scenario A1B. Nevertheless, the new result lowers the overall sea level rise under this scenario by about 2 inches or about 13%.

Clearly, the Raper and Braithwaite results fall under the category of sea level rise is “NOT going to be as bad as we thought” and adds to a growing number of model simulations and observations that suggest that future sea level rise will prove to be far less than the extremists advertise (see here and here for example). We guarantee that had they reported that sea level rise was going to be 13% “worse than we thought,” headlines would have been made around the world.

So kudos to Raper and Braithwaite for writing up their results and to Nature for actually publishing them. Now let’s sit back and see how the press handles it.


Raper, S.C.B., and R.J. Braithwaite, 2006. Low sea level rise projections from mountain glaciers and icecaps under global warming. Nature, 439, 311-313.

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