Once again, the IPCC estimates are proving to be underestimates of the problem of climate change. That’s what you get with consensus. Yes, we’re confident that the results will be at least as bad as the IPCC forecasts, else some country with financial interests in continuing to burn fossil fuel will reject the statement. But, what we don’t get is the full range of estimates. We get the most watered down statement, not a statement of the greatest odds.
Sea-level rise has been a particularly contentious element in the debate over global warming. One published estimate suggested the threat was so dire that sea level could rise as much as 15 feet in this century. Some of the recent work that produced the three-foot projection was carried out specifically to counter more extreme calculations.
Got that? At least one scientific paper projected a 15 foot rise in sea level by the end of the century. People don’t want to hear that. We better fund another study that will tone it down a bit. But, even the toned down 2.5-6.5 foot estimate is seriously catastrophic.
Calculations about the effect of a three-foot increase suggest that it would cause shoreline erosion to accelerate markedly. In places that once flooded only in a large hurricane, the higher sea would mean that a routine storm could do the trick. In the United States, an estimated 5,000 square miles of dry land and 15,000 square miles of wetlands would be at risk of permanent inundation, though the actual effect would depend on how much money was spent protecting the shoreline.
The worst effects, however, would probably occur in areas where land is sinking even as the sea rises. Some of the world’s major cities, especially those built on soft sediments at the mouths of great rivers, are in that situation. In North America, New Orleans is the premier example, with large parts of the city already sitting several feet below sea level.
Defenses can be built to keep out the sea, of course, like the levees of the New Orleans region and the famed dikes of the Netherlands. But the expense is likely to soar as the ocean rises, and such defenses are not foolproof, as Hurricane Katrina proved.
Storm surges battering the world’s coastlines every few years would almost certainly force people to flee inland. But it is hard to see where the displaced would go, especially in Asia, where huge cities — and even entire countries, notably Bangladesh — are at risk.
Thankfully, we know that the world will not in fact be destroyed by global warming …. Funny that this doesn’t really give me confidence in his conclusion.