J.Boex, C. Fogwill, S. Harrison, N.F. Glasser, A. Hein, C. Schnabel and S. Xu. Rapid thinning of the Late Pleistocene Patagonian Ice Sheet followed migration of the Southern Westerlies. Scientific Reports 3: 2118, p. 1-6
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The Patagonian Ice Sheet
Patagonian mountains east of the North Patagonian Icefield. Credit: Stephan Harrison
This recent open-access paper in the new journal Science Communications, which is part of the Nature group, has demonstrated that the during the deglacial period (~19,000 years ago), the Patagonian Ice Sheet in South America responded rapidly in response to changing precipitation patterns and warming during the last deglaciation. The fact that the Patagonian Ice Sheet responded so quickly to changes in precipitation and temperature has vivid implications for the current, and future, behaviour of the current North Patagonian Icefield and South Patagonian Icefield. We already know that the shrinkage of the North and South Patagonian ice fields was faster over the last decade or so than at any point in the last couple of centuries. Understanding on a broader scale how these sensitive, high-latitude ice masses are dependent on small changes in atmospheric circulation means that we will better be able to predict the future behaviour of these ice sheets. Reconstructing rates of ice-sheet decay since the Last Glacial Maximum means that we can better assess the mechanisms of climate change (including changing wind patterns) during a major climate transition. Continue reading
Sea ice and ice shelves
What is sea ice? Sea ice is frozen sea water; it perennially expands and contracts during each year’s winter and summer. Amongst the sea ice are icebergs calved from tidewater glaciers and ice shelves. Melting sea ice does not contribute directly to sea level rise (ice floats and displaces the same volume of water), but sea ice is important because it enhances climate warming. It changes the reflectivity of the sea water, reflecting lots of sunlight back (it has a high albedo), and is therefore an important component of the climate and cryospheric (icey) system.
A new paper in Nature Climate Change by Bamber and Aspinall attempts to untangle the thorny problem of how quickly and how much the ice sheets of the world will melt. The rate at which ice sheets melt is difficult to understand, because there are many processes that occur. Continue reading
How much ice is there in Antarctica? And if it were to melt, how much would global sea levels rise, and how quickly? Continue reading
The Arctic’s sea ice extent reached an all-time low in September 2012, with the smallest recorded extent since satellite observations began. At 3.42 million square kilometres, it may still sound large, but this small extent of Arctic sea ice could have profound long-term consequences, and it follows a long trend of low sea ice conditions. Sea ice extent has been decreasing over the past 4-5 decades (Kinnard et al., 2011), and sea ice extent is now about 2 million square kilometres less than it was during the late twentieth century. Continue reading
In this new website, www.greenlandmelting.com, you can browse maps of the surface melt on Greenland in each year from 1979. You can also look at years with extreme melt events, such as 2010 and 2011.
Proving Climate Change
When reading the New Scientists’ focus on Climate Change, I was struck by the number of comments along the lines of, ‘This is theory, we won’t believe it until you prove it’. Two things came to my attention. Firstly, that climate change has been accorded almost myth or religious-like status, and has become something that you can either ‘believe’ or ‘disbelieve’. Secondly, that many people are profoundly naive about the way in which science works. And so I was motivated to write a brief piece about scientific research design. Stay with me now – I’ll make it as interesting as possible! Continue reading