Sea Level Rise Surprise

Driving the seemingly endless climate-treaty negotiations, the most widely feared consequence of Global Warming appears to be a catastrophic rise in sea level (SLR). Environmental advocacy groups are filling the airwaves with lurid images of flooding of Bangladesh and Pacific islands, and raising the specter of hundreds of millions of environmental refugees demanding care and compensation.
Even sober scientists, while not endorsing such obvious scare stories, predict an acceleration of the ongoing global rise, which a system of tidal gauges places at about 18 cm (7 inches) during the 20th century. Economists concerned with trying to estimate a 'social cost' of carbon-dioxide emissions predict huge economic losses from future SLR. Not surprisingly, insurance companies, looking to raise premiums, are cheering them on.
However, more detailed analyses of actual observations suggest an opposite outcome: A climate warming might even slow down SLR -- rather than accelerate it. To understand this counter-intuitive result, one must first get rid of false leads -- just as in a detective story. The misleading argument here is the oft-quoted statement that the climate warmed by 1degF (0.6 C) in the last 100 years and that SL rose by 18 cm. Both parts of the statement may well be true; but the second part does not necessarily follow from the first.
Curiously, Barack Obama predicted a deceleration of SLR when he accepted his party's nomination in 2008: "This was the moment when the rise of the oceans began to slow, and our planet began to heal." Some tidal-gauge data do show deceleration, but starting in 1960. Hey, wasn't that the year during which Obama was conceived?

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