Melting the Ice (But Not in a Fun, Life-of-the Party Way)

The Ny Times has a lengthy article about glacial melting and sea level rise, with bad news:

But researchers have recently been startled to see big changes unfold in both Greenland and Antarctica.

As a result of recent calculations that take the changes into account, many scientists now say that sea level is likely to rise perhaps three feet by 2100 — an increase that, should it come to pass, would pose a threat to coastal regions the world over.

And the calculations suggest that the rise could conceivably exceed six feet, which would put thousands of square miles of the American coastline under water and would probably displace tens of millions of people in Asia.

Here’s what appears to be the mechanism behind the unexpectedly rapid loss of glacial ice:

Water that originated far to the south, in warmer parts of the Atlantic Ocean, is flushing into Greenland’s fjords at a brisk pace. Scientists suspect that as it melts the ice from beneath, the warm water is loosening the connection of the glaciers to the ground and to nearby rock.

My general policy is to respond cautiously to climate studies that have really bad news, for several reasons: (1) they may be outliers, (2) we often don’t have really good data, especially in terms of the past, so it’s hard to be sure what’s a real change and what’s just the fluctuating background noise, and (3) we all have a natural tendency to fixate on dramatic news. For the same reasons, I’m also cautious about studies that show unexpectedly small climate effects  In either case, it’s wise to remember that “one swallow doth not a summer make,”* and not to put too much weight on a single study or two.

Nevertheless, it seems that the “best guess” estimate of sea level rise has just gotten higher, and of course this means that the right tail of the curve has gotten scarier.  And if these results are confirmed by further research, we’ll really have reason to worry — the planet’s warming has just begun, so dramatic changes now are signals of much worse to come.

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* I always assumed that this line was from Shakespeare, but a quick look on-line reveals that it’s Aristotle: μία χɛλίδὼν ἕαρ οὐ ροίɛῖ .

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