The West Antarctic Ice Sheet Melt: Defending the Drama
BY ELIZABETH KOLBERT
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...In more recent years, even as forecasts of global sea-level rise have been notched up, most projections have not taken into account the possibility of a significant, near-term ice loss from the West Antarctic. The most recent analysis by the U.N.’s Intergovernmental Panel on Climate Change forecasts a global sea-level rise for this century of somewhere between one and three feet; the new findings, according to Rignot, will require these figures to be revised upward.
Of the many inane arguments that are made against taking action on climate change, perhaps the most fatuous is that the projections climate models offer about the future are too uncertain to justify taking steps that might inconvenience us in the present. The implicit assumption here is that the problem will turn out to be less serious than the models predict; thus, any carbon we have chosen to leave in the ground out of fear for the consequences of global warming will have gone uncombusted for nothing.
But the unfortunate fact about uncertainty is that the error bars always go in both directions. While it is possible that the problem could turn out to be less serious than the consensus forecast, it is equally likely to turn out to be more serious. In fact, it increasingly appears that, if there is any systemic bias in the climate models, it’s that they understate the gravity of the situation. In an interesting paper that appeared in the journal Global Environmental Change, a group of scholars, including Naomi Oreskes, a historian of science at Harvard, and Michael Oppenheimer, a geoscientist at Princeton, note that so-called climate skeptics frequently accuse climate scientists of “alarmism” and “overreacting to evidence of human impacts on the climate system.” But, when you actually measure the predictions that climate scientists have made against observations of how the climate has already changed, you find the exact opposite: a pattern “of under- rather than over-prediction” emerges. The scholars attribute this bias to the norms of scientific discourse: “The scientific values of rationality, dispassion, and self-restraint tend to lead scientists to demand greater levels of evidence in support of surprising, dramatic, or alarming conclusions.” They call this tendency “erring on the side of least drama,” or E.S.L.D. for short.
Unfortunately, we live in dramatic times. Yesterday’s news about the West Antarctic Ice Sheet is just the latest reminder of this; there will, almost certainly, be much more “surprising” and “alarming” news to follow. Which is why counting on uncertainty is such a dangerous idea.
the rest
http://www.newyorker.com/online/blogs/elements/2014/05/the-west-antarctica-ice-sheet-melt-defending-the-drama.html
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