Andy Revkin at the NYTimes' DotEarth blog has posted the lead story on the New York Times' website this afternoon, saying that the collapse of the West Antarctic ice sheet would raise sea levels by 10 feet, not 20. For most scientific disciplines, these arguments over magnitude and implications of change take place quietly. However, climate change is a major topic of public policy, so the scientists get front-page coverage. This is not he best place for these arguments to happen, because it muddies the water, and promotes paralysis.
There seems to be a continuing litany of studies -- some extrememly worrying, and some that are vaguely reassuring (i.e. Downtown Manhattan will only be partially, not completely flooded). It is unfortunate, however, for leaders and policymakers that there seems to be so much 'noise' but little consensus.
In 2007, the IPCC created a strong international consensus that climate change was a threat that must be addressed. The result was the Bali roadmap.
Two years later, the studies and observations are almost uniformly worse than IPCC predictions. Unfortunately, these studies often disagree and there is no coordination. The result is this 'noise' that only serves to undermine political will and cause paralysis among leaders. I'm afraid the result will be the collapse of Copenhagen.
The IPCC must move faster in preparing their next report.