I’ve always assumed that a 5 meter sea level rise would be catastrophic – is that too simple?

I have no patience with the “It isn’t happening” view of climate change, which to me is part of the anti-rationalist view of the world. (The battle over the relative merits of Faith and Reason was supposedly settled, at least in Europe, by the Enlightenment, and the supporters of Reason won.)  Pumping large amounts of greenhouse gasses into the atmosphere must increase temperatures, and the burden of proof is on those who claim that it hasn’t and won’t. But everything (else) is susceptible to analysis, with no presumption that any particular conclusion is valid.

One of the surprises I have run into is the seemingly small estimates of damages in, say, the next 50 years.  Some of them are on the order of  2 percent of GDP, which is really not much: equivalent to a change in economic growth rate of .2%  for 10 years, or (for the US) a 10 percent change in our health care bill. Can it be so small, when we consider effects such as 1) reduction in land area, 2) increased disease in many areas, 3) disruptions of weather and hence agriculture?

If the total effects of climate change are really this magnitude, then R&D should be addressed to coping strategies as much as to prevention. Here is a comment by Bjorn Lomborg on one of the effects: loss of coastline.

Even the worst-case scenarios proposed by mainstream climate scientists – scenarios that go far beyond what the consensus climate models predict – are not as bad as Gore would have us believe. For example, a sea-level rise of five meters – more than eight times what the United Nations’ Intergovernmental Panel on Climate Change expects, and more than twice what is probably physically possible – would not deluge all or even most of mankind.Of course, such a rise would not be a trivial problem. It would affect about 400 million people, force the relocation of 15 million, and imply costly protection of the rest. But it would certainly not mean the end of the world. Estimates show that the cost in terms of adaptation would be less than 1% of global GDP. In other words, the price of unchecked global warming may be high, but it is not infinite.According to the best global-warming economic models, every ton of carbon dioxide that we put into the atmosphere now will do about $7 worth of damage to the environment. What this means is that we should be prepared to pay an awful lot to stop global warming, but anything more than $7 a ton would be economically indefensible.

via Cars, Bombs, and Climate Change – Project Syndicate.

I did a few minutes of research, and could not find anything rigorous on the relationship between sea level and land area. But I did find a Google Map at http://flood.firetree.net that is consistent with Lomborg’s numbers. It shows the direct effect on coastal margins. However, as the map’s author points out, there are a number of inaccuracies in the map. For example, I visit San Diego beaches frequently. Very little land area here would be directly inundated, but erosion effects would be major after a few decades of tides and storms.

Any pointers to newer/better analysis on this issue?