Mapping the Polar Regions
Published 9th October 2014 by The Times Atlas
New maps of the polar regions reveal unseen world beneath the ice and highlight dramatic decline in Arctic sea ice cover
New maps of the sub-ice features in Antarctica and the Arctic, featured in the new edition of The Times Comprehensive Atlas of the World reveal an unseen world of canyons, lakes, trenches and mountains. The 14th edition of the Atlas also includes a new double page map of the Arctic Ocean, which highlights the dramatic long-term decline of Arctic sea ice cover.
The sub-ice maps draw on bedrock data to show physical features which are obscured by ice cover. In the Antarctic, one of the most striking features is the Gamburtsev Subglacial Mountains, which are as large as the Alps but are currently completely covered by ice.
Also featured are the deep subglacial trenches such as the Thiel Trough and the Bentley Subglacial Trench, the latter reaching a depth of 2496 m, one of the deepest points on the continent. The map shows the location of Lake Vostok and Recovery Lakes which exist beneath the ice, and the East and West Lambert Rifts from which ice flows into the Amery Basin, draining the largest glacier system in Antarctica. The Astrolabe Subglacial Trench, which contains the thickest ice in the world is also named on the map.
In the Arctic, Greenland’s ‘mega canyon’ of record length, over 750 km long and 800 m deep, discovered under the Greenland Ice Sheet in 2013 is clearly visible on the map running from south to north. The canyon, which is thought to predate the overlying ice sheet, remains unnamed although Greenland's ‘Grand Canyon’ or ‘Grand Canyon of Greenland’ have been put forward as tentative name suggestions. The maps show the current elevation of features beneath the ice. If the weight of ice covering was reduced the land would very gradually rebound or rise up.
Peter Fretwell of the British Antarctic Survey said:
“It is very important to know how much ice there is and what the topography of the bed looks like, as this is one of the main controls on how quickly ice sheets melt with climate change.”
Listen to Peter Fretwell on the BBC's Science in Action programme.
In addition to maps of sub-ice features, the new edition of The Times Comprehensive Atlas of the World also includes a new map of the Arctic Ocean which provides a comprehensive picture of long-term trends in Arctic sea ice cover. The map shows the average summer sea ice extent from 1981 to 2010 as well as the 2012 record-low summer ice extent, which was 45 per cent lower than the 30 year average. The map also shows the minimum extent of summer 2013, 18 per cent lower than the 30 year average.
Arctic sea ice cover grows each winter and shrinks each summer, reaching its minimum extent in September. It is considered by many scientists to be a sensitive climate indicator and they track this minimum extent every year to see if any trends emerge. The National Snow and Ice Data Center (NSIDC), our data source for Arctic sea ice extent, defines it as the area of the ocean having at least 15 per cent sea ice cover.
Walt Meier, research scientist at the Cryospheric Science Branch, NASA Goddard Space Flight Center, said:
“End of summer sea ice extent averages 40 per cent less than it used to be in the early 1980s. The ice is also substantially thinner, about half the thickness on average than during the 1980s. The loss of sea ice results in more energy being absorbed in the Arctic, contributing to amplified warming compared to the rest of the globe.”
The new, completely revised and updated, edition of The Times Comprehensive Atlas of the World contains 320 pages of maps and illustrations which show the scale of the world’s physical features, states and territories in exceptional detail, unconstrained by the limits of a screen.
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