Astray in Greenland

Article excerpt


In very large type, the New York Times Jan. 16 proclaimed "The warming of Greenland." But as has become increasingly typical of their reporting on climate change, that's only about half the news that's fit to print.

The big story, of course, is the melting of Greenland's ice, and threats of a major rise in sea level. After all, if the entire 630,000 cubic miles of it disappeared, the ocean would rise 23 feet.

The Times relied on an off-the-cuff estimate of ice loss, given to it by Professor Carl Boggild from the University Center at Svalbard. The Times reported he "said Greenland could be losing more than 80 cubic miles of ice per year."

Nowhere did the Times give the amount determined by meticulous analysis of recent satellite data, which is around 25 cubic miles, published by NASA's Scott Luthcke in Science less than two months ago.

It then quoted Richard Alley, from Penn State, who reported "a sea-level rise of a foot or two in the coming decades is entirely possible." Wrong. It's entirely impossible.

First, the current sea-level rise contributed by this amount of ice loss is probably too small to even be able to measure in coming decades. The satellite data show a reduction of 3 hundred-thousandths of Greenland's total ice per year (while Mr. Boggild's figure "could" be around 12 hundred-thousandths [0.000012]).

Multiplying the satellite-based figure by 23 feet gives the annual rise in sea level of .01 inch per year. Averaged over three decades, that's a third of an inch, which indeed is too small to be detectable. Over a century, the rise becomes a bit more than an inch. Mr. Boggild's guesstimate yields 31/2 inches per century.

In fact, there's nothing very new going on in Greenland. While the Times pays great attention to ice-loss in eastern Greenland caused by current temperatures, it conveniently forgets to look at nearby temperature histories. The longest record is from Angmagssalik. In the summer (when Greenland's ice melts) the temperature has averaged 43.1 degrees Fahrenheit over the last 10 summers. There was one very warm summer, in 2003, but the other nine years aren't unusual at all.

From 1930 through 1960, the average was 43.7 degrees. In other words, it was warmer for three decades, and there was clearly no large rise in sea level. What happened between 1945 and the mid-1990s was a cooling trend, with 1985-95 being the coldest period in the entire Angmagssalik record, which goes back to the late 19th century. Only in recent years have temperatures begun to look like those that were characteristic of the early 20th century.

Petr Chylek, from Canada's Dalhousie University, recently summarized Greenland's climate history in the journal Geophysical Research Letters. …