There were a flurry of news articles recently covering a survey study by the Scientific Committee on Antarctic Research. The BBC was typical with this headline "Major Sea Level Rise, as Antarctic Melts." The subhead of the article uses a 1.4M high end for the rise in sea level.
The article starts with the IPCC projections of 28-43 cm, which isn't the full range in any event. Says that the IPCC report concluded that this was "almost certainly too low", which is wrong, and then goes on with quotes from the director of the survey.
Colin Summerhayes, I guess sensing that the rest of the report's conclusions are dull, discusses the Antarctic contribution to sea level rise. He says it could add "tens of centimeters." So you might wonder how do get from tens of centimeters to a meter of additional rise. Well you have to add in melt from other areas. What is his basis for doing that. Well he doesn't have one. Maybe his feeling.
So, of course rather than trying to figure this out from a news story I went to the actual report. And what you learn when you do that is that it is even an attempt to make a new sea level estimate. The 1.4M figure is taken from my old friend Rahmstorf 2007. I wonder if they get a free shopping day for being the one millionth citation to this weakly argued paper.
The BBC says that many other studies support these conclusions but fail to mention any. And I might add that the only http://www.scar.org/publications/occasionals/ACCE_Addendum_01Dec09.pdf to the SCAR paper makes it clear that the conclusion is entirely based on the Rahmstorf paper. It would seem to be pretty embarrassing that one of the main conclusions that you talk about from your study group is based on a single paper from three years earlier.
Some might fall back on the conclusion that the West Antarctic Ice Sheet would contribute tens of centimeters. This led them to look for the Rahmstorf study since perhaps it was so different than the IPCC report. But this seems to be based on the myth that the IPCC report didn't account for glacial melt in Antarctica. Section 10.6.3 fully discusses this contribution. There is no attempt in this study to reconcile their conclusions with the conclusions of the IPCC chapter.
Reading the SCAR release you can't blame this one on the press. They make the 1.4M meter forecast one of their main bullet points, even though they are just referencing a single three year old paper. I once again am tired of having to do forensic analysis on just about everything published by the scientific community to figure out what they really studied and what they are really concluding.