Yesterday two scientists at the University of Colorado announced their finding that Antarctica’s massive ice sheets are shrinking by 36 cubic miles a year, the first evidence that the continent’s ice mass is shrinking significantly.
While it is a small, preliminary finding, the Colorado study — combined with a recent report of accelerated glacial melting in Greenland — does suggest, said the Los Angeles Times, “that a century of steady increases in global temperatures is altering the seasonal balance of the world’s water cycle, in which new snow and ice neatly offset thaw and rainfall runoff every year to maintain the current level of the seas.”
The news brought a flurry of coverage at outlets across the country, some better than others. We start off in Denver, where the city’s two major dailies each produced stories on Antarctica’s shrinking ice today.
The Denver Post carried a cleverly titled (“CU study slakes thirst for Antarctic ice-melt data”) but thin story, reporting that the melting ice is equal to 264 billion gallons of water or “a four-tenths of a millimeter rise in global sea levels annually” and that the study “is the first to quantify the decline of the ice sheet — which is twice as large as Australia — due to global warming.” “For the first time, we can come up with a number and say the Antarctic ice sheet is losing significant mass and contributing to a rising sea level,” said Isabella Velicogna, the study’s principal author. The Post also reported the important background details that “[t]he study challenges the belief by scientists that snowfall on the interior of the ice sheet counters glacial loss on the edges” — an international climate change panel predicted in 2001 that Antarctica would actually add to its ice mass over the course of this century due to increased snowfall — and that “[a] Delaware-size block of ice that disintegrated into the ocean four years ago uncorked a flow of glaciers toward the ocean.”
A much better story was produced by Post rival the Rocky Mountain News, which did an excellent job explaining the science behind the news for its readers.
“During their study, Antarctica lost enough ice to raise global sea levels by about 1.2 millimeters. That may not seem like much — a millimeter is about the thickness of the wire used in a paper clip,” the Rocky reported. “But the observed rate is twice as high as Antarctica’s annual contribution to sea-level rise over the past century.” Besides discussing in some depth the study’s complex backdrop and the far-from-settled implications of its results, the Rocky clearly explained the role of the two NASA satellites used to gather the researchers’ data.
While the Rocky (like the Post and a few other papers today) mistakenly referred to a single Antarctic ice sheet - when in fact the continent has two great sheets to the east and west — it was the clear winner of this local news battle.
Elsewhere, the New York Times published a short, unremarkable article, but the Atlanta Journal-Constitution put together a more inspired piece. “By itself, a millimeter increase in sea level [over three years] is no cause for great concern, but the rate of increase, roughly double the average annual increase over the last century, has researchers watching the largest reservoir of ice on the planet for hints about how it may respond to the changing climate,” reported the AJC, which quoted study co-author John Wahr saying, “The changes we are seeing are quite clearly global warming at work.”
Giving a larger perspective the Denver papers did not, the AJC reported that “[i]n recent years, scientists have reported the retreat of mountain glaciers throughout the world — and more recently, signs that Greenland’s polar ice sheet is melting faster.” The paper added that scientists have recently “watched as the breakup of ice shelves along the seaward edge of the West Antarctic Ice Sheet spawned massive floes, some of them hundreds of miles long” — a disintegration which has allowed ice streams from Antarctica’s interior to push toward the sea more quickly.