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Did the west Antarctica Ice Sheet survive a warm spell?
Did Antarctic ice defy warmer world? Jeff Hecht
WHETHER Antarctica’s ice will survive a warmer world is one of the great puzzles of climate science. Now it seems vast expanses of ice may have hung on for the past 200,000 years, surviving the last interglacial. The west Antarctic ice sheet’s base is below sea level, which should make it unstable. If it were to collapse the torrent of fresh water could raise global sea level by 5 metres. Whether or not this will happen as temperatures climb is a hotly debated topic. A new study by David Sugden at the University of Edinburgh, UK,
and colleagues suggests the ice sheet may be more stable than we thought. They studied the Heritage range of mountains near the central dome of the west Antarctic ice sheet. Specifically, the researchers looked at blue-ice moraines, where winds erode the ice in topological depressions, exposing the rocks beneath. They analysed the moraine for beryllium isotopes produced by cosmic radiation, which accumulate in the rock when it is exposed. Sugden’s team found evidence that the moraines had been forming for at least 200,000 years, suggesting that ice has covered the area for at least that
l. sass/arctic photo
For daily news stories, visit www.NewScientist.com/news
nature08686) suggests sea levels were 8 to 9 metres higher than now during the last interglacial, in part due to the west Antarctic ice sheet melting. If Sugden’s team is correct, that amount of sea level rise would be unlikely. Working out who is right is a “frustrating and intriguing scientific riddle that we’d love to unravel”, says Richard Alley of Pennsylvania State University in University Park. Even if the central parts of the ice sheet can survive a warming –Staying solid for now– climate, melting is likely at the extremities, says Sugden. Tim long (Palaeogeography, Naish of Victoria University in Palaeoclimatology, Palaeoecology, Wellington, New Zealand, agrees. DOI: 10.1016/j.palaeo.2011.01.027), With melting at the edges and in and therefore survived the last Greenland, “we’re looking at a rise interglacial 125,000 years ago. of one metre plus or minus 0.5 Don’t expect this to be the final metres” by 2100, he says – double word on the matter. A recent the maximum predicted in 2007 study by Robert Kopp at Princeton by the Intergovernmental Panel University (Nature, DOI: 10.1038/ on Climate Change. n
Learning a language? Consider it child’s play. Think about how you learnt your native language as a child. The world was your classroom, but there were no lessons. You were an active participant in the process of learning, but it all seemed like fun and games. Like child’s play.
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©2011 Rosetta Stone (UK) Ltd. All rights reserved. Patent rights pending. Offer cannot be combined with any other offer. *£50 off SRP when you buy Level 1, 2, 3, 4 & 5 Personal Edition box set direct from Rosetta Stone. £40 off SRP when you buy Level 1, 2 & 3 Personal Edition box set direct from Rosetta Stone. Plus free standard P&P within the UK. Offer expires 30th April 2011. Prices are subject to change without notice. Six-month money-back offer is limited to product purchase made directly from Rosetta Stone and does not include return P&P. This offer does not apply to Rosetta Stone Online or Audio Companion® purchased separately from the software product. All materials included with the product at the time of purchase must be returned together and undamaged to be eligible for any exchange or refund.
5 March 2011 | NewScientist | 11
WHETHER Antarctica’s ice will survive a warmer world is one of the great puzzles of climate science. Now it seems vast expanses of ice may have hung on for the past 200,000 years, surviving the last interglacial. The west Antarctic ice sheet’s base is below sea level, which should make it unstable. If it were to collapse the torrent of fresh water could raise global sea level by 5 metres. Whether or not this will happen as temperatures climb is a hotly debated topic. A new study by David Sugden at the University of Edinburgh, UK,
and colleagues suggests the ice sheet may be more stable than we thought. They studied the Heritage range of mountains near the central dome of the west Antarctic ice sheet. Specifically, the researchers looked at blue-ice moraines, where winds erode the ice in topological depressions, exposing the rocks beneath. They analysed the moraine for beryllium isotopes produced by cosmic radiation, which accumulate in the rock when it is exposed. Sugden’s team found evidence that the moraines had been forming for at least 200,000 years, suggesting that ice has covered the area for at least that
l. sass/arctic photo
For daily news stories, visit www.NewScientist.com/news
nature08686) suggests sea levels were 8 to 9 metres higher than now during the last interglacial, in part due to the west Antarctic ice sheet melting. If Sugden’s team is correct, that amount of sea level rise would be unlikely. Working out who is right is a “frustrating and intriguing scientific riddle that we’d love to unravel”, says Richard Alley of Pennsylvania State University in University Park. Even if the central parts of the ice sheet can survive a warming –Staying solid for now– climate, melting is likely at the extremities, says Sugden. Tim long (Palaeogeography, Naish of Victoria University in Palaeoclimatology, Palaeoecology, Wellington, New Zealand, agrees. DOI: 10.1016/j.palaeo.2011.01.027), With melting at the edges and in and therefore survived the last Greenland, “we’re looking at a rise interglacial 125,000 years ago. of one metre plus or minus 0.5 Don’t expect this to be the final metres” by 2100, he says – double word on the matter. A recent the maximum predicted in 2007 study by Robert Kopp at Princeton by the Intergovernmental Panel University (Nature, DOI: 10.1038/ on Climate Change. n
Learning a language? Consider it child’s play. Think about how you learnt your native language as a child. The world was your classroom, but there were no lessons. You were an active participant in the process of learning, but it all seemed like fun and games. Like child’s play.
That’s the secret to Rosetta Stone ®. It unlocks your brain’s natural ability to learn a language. You’ll learn through engaging, interactive activities that encourage you to think in the new language. And just like a child, you won’t memorise or translate. You’ll have fun as you progress, and you’ll find it easy to achieve your language learning goals. OVER 30 LANGUAGES AVAILABLE
UP TO £50 OFF PLUS FREE DELIVERY Quote ‘NST3’
Call 0800 005 1630
RosettaStone.co.uk/NST3 OUR PROMISE IS YOUR
PEACE OF MIND
SIX-MONTH MONEY-BACK GUARANTEE
©2011 Rosetta Stone (UK) Ltd. All rights reserved. Patent rights pending. Offer cannot be combined with any other offer. *£50 off SRP when you buy Level 1, 2, 3, 4 & 5 Personal Edition box set direct from Rosetta Stone. £40 off SRP when you buy Level 1, 2 & 3 Personal Edition box set direct from Rosetta Stone. Plus free standard P&P within the UK. Offer expires 30th April 2011. Prices are subject to change without notice. Six-month money-back offer is limited to product purchase made directly from Rosetta Stone and does not include return P&P. This offer does not apply to Rosetta Stone Online or Audio Companion® purchased separately from the software product. All materials included with the product at the time of purchase must be returned together and undamaged to be eligible for any exchange or refund.
5 March 2011 | NewScientist | 11