NEWS OF THE WEEK

CLIMATE CHANGE

Both of the World’s Ice Sheets From the Science May Be Shrinking Faster and Faster Policy Blog Scientists complain that the The two great ice sheets—Greenland’s and GREENLAND ICE MASS U.S. Army’s claims of success with an AIDS Antarctica’s—have had plenty of press lately, vaccine tested in Thailand are undermined what with galloping glaciers and whole lakes 1000 Unfiltered data by an unrevealed second analysis. That of meltwater plunging into ice holes in min- 800 Seasonally filtered data result found a drop in vaccine efficacy and Best-fitting trend utes (Science, 18 April 2008, p. 301). Sur- 600 no statistical significance when it com- veys of ice-sheet volume made from planes 400 pared vaccinated and control groups that and satellites have quantified these losses, 200 rigorously followed the protocol. but those assessments have been spotty in 0 http://bit.ly/lHVr8 time, space, or both. Shrinkage accelerated -200

from the 1990s into the 2000s, but Ice Mass (gigatons) -400 A number of scientists are outraged over a researchers couldn’t be sure what would -600 new program to use DNA and tissue come next. -800 samples to determine the nationality of Now the latest analysis of the most com- -1000 applicants for asylum by the U.K. Border prehensive, essentially continuous monitor- 2003 2004 2005 2006 2007 2008 2009 Agency. After ScienceInsider revealed scien- ing of the ice sheets shows that the losses Bending down. The trend line of Greenland ice tific condemnation of its plans to conduct have not eased in the past few years. More mass (green) curves downward with time, suggesting DNA tests and isotope analyses to deter- ominously, losses from both Greenland and that losses have been accelerating. mine nationality (Science, 2 October, Antarctica appear to have accelerated dur- p. 30), the U.K. Border Agency this week on November 3, 2009 ing the past 7 years. If the acceleration out Antarctica, the loss rate more than doubled to changed its plans, saying such evidence of the 1990s “was a hiccup, it was a big one, produce a similar acceleration. Together, that would not yet be used in asylum decisions. and it’s getting bigger,” says glaciologist would make for a 5% acceleration each year in http://bit.ly/2QxWBG Richard Alley of Pennsylvania State Uni- the rise of sea level. Compounded year after versity, University Park, who was not year, “that is a big thing,” says Velicogna. “We Energy Secretary Steven Chu tried to per- involved in the work. should be more concerned.” suade Congress to fund eight Energy Inno- The results, in press at Geophysical The GRACE observations counter vation Hubs next year, but in a spending Research Letters, are based on measure- encouraging news from southeastern Green- bill passed last week, Congress supported

ments by the Gravity Recovery and Cli- land that the surging glaciers there had only three. http://bit.ly/2GPoDK www.sciencemag.org mate Experiment (GRACE) satellite mis- slowed (Science, 23 January, p. 458). The sion. Rather than measuring the volume of slowing was probably real, says Alley, but A controversy at the Proceedings of the ice sheets every few years as most earlier apparently the increasing losses from melt- National Academy of Sciences over the surveys did, GRACE “weighs” them from ing and accelerating glaciers elsewhere journal’s standards for peer review took a month to month with a pair of spacecraft around Greenland at least made up for the new turn when it decided to postpone the launched in March 2002 as a joint NASA slowing in the southeast. Whatever is driv- publication of a controversial paper on but- and German Aerospace Center mission ing ice loss—warmer oceans, warmer air, or terflies that was already accepted and pub- Downloaded from (Science, 14 August, p. 798). Flying in tan- both—is persisting, he says. lished online. http://bit.ly/zhJsk dem 220 kilometers apart, the satellites Glaciologist Waleed Abdalati of the can measure subtle variations in the pull of University of Colorado, Boulder, says A new study conducted by the National gravity as they pass over a large mass on Velicogna’s analysis “suggests—that’s the Football League suggested that playing the surface. By beaming microwaves from key word—that there’s been an acceleration professional American football increases one to the other, they precisely gauge the in the period examined. We have to be care- the risk of dementia, increasing pressure changing distance between them as the ful to not overinterpret and speculate about on the sport to study the problem. added mass tugs first on the leading satel- the future.” The record is too short to be http://bit.ly/wO8cd lite and then on the trailing one. Changes extrapolated into the future, Abdalati says. GEOPHYSICAL RESEARCH LETTERS in gravity from pass to pass reflect changes And at least in Greenland, it was affected Congress has given the U.S. Department of in the icy mass below. by the extreme warmth and resulting melt- Energy’s Office of Science a 2.7% boost in The mass changes of Greenland and ing in 2007, a loss surge that might not be its 2010 budget, to $4.9 billion. The $131 Antarctica during the past 7 years have all repeated in the next 7 years. million increase comes as the overall been negative, geophysicist Isabella If bursts of ice loss do occur soon, budget for the $27 billion agency was held Velicogna of NASA’s Jet Propulsion Labora- GRACE may not be around to record it. Its relatively flat. http://bit.ly/fQLdN tory in Pasadena, California, concludes in the two satellites will fall from orbit around 2013, study. On Greenland, she calculates, the rate dragged down after a decade of orbiting For more science policy news, visit of ice mass loss doubled over the 7-year through Earth’s outermost atmosphere. No blogs.sciencemag.org/scienceinsider. period, producing an acceleration of replacement gravity mission is yet planned.

CREDIT: ADAPTED FROM ISABELLA VELICOGNA, CREDIT: –30 cubic kilometers of water lost per year. On –RICHARD A. KERR

www.sciencemag.org SCIENCE VOL 326 9 OCTOBER 2009 217 Published by AAAS