Scientists call Times World Atlas Greenland claims 'incorrect and misleading'

  • 19 Sep 2011, 13:39
  • Christian Hunt

With Arctic sea ice just past its annual summer minimum, interest in the Arctic has reached its annual peak. Perhaps timed to coincide with the sea ice minimum, the marketing effort accompanying the launch of the new edition of the Times World Atlas leaned heavily on the redrawn maps of Greenland featured in the atlas, which appear to show the ice cap in retreat.

But now scientists have raised questions about how the Atlas came to their conclusions about the ice cap, about the press release put out to mark the publication of the 13th edition of the definitive tome, and about the maps themselves.

The press release claimed:

For the first time, the new edition of The Times Comprehensive Atlas of the World, published on 15 September, has had to erase 15% of Greenland's once permanent ice cover - turning an area the size of the United Kingdom and Ireland 'green' and ice free… Cartographers of the atlas have sourced the latest evidence and referred to detailed maps and records to confirm that in the last 12 years, 15% of the permanent ice cover (around 300,000 sq km) of Greenland, the world's largest island, has melted away.

Needless to say, this story was widely picked up. ITN covered the story and interviewed the Atlas' editor, and it reached the Australian Daily Telegraph and the UK's Daily Express, while John Vidal writing in the Guardianrepeated the press release's claim:

The world's biggest physical changes in the past few years are mostly seen nearest the poles where climate change has been most extreme. Greenland appears considerably browner round the edges, having lost around 15%, or 300,000 sq km, of its permanent ice cover.

Research into the Greenland ice sheet confirms that it is losing ice as the Arctic region warms. But concerns were raised on Twitter when scientists contacted the Guardian suggesting that the figures they had quoted were questionable.

The BBC reports that scientists from the Scott Polar Research Institute, University of Cambridge, have written a letter to the Times taking issue with the erroneous 15% claim.

The problem with the 15% claim is that the Times Atlas maps seem to be at odds with in-situ and satellite measurements, showing areas of Greenland as ice-free when they are in reality covered by ice. The letter says:

"Recent satellite images of Greenland make it clear that there are in fact still numerous glaciers and permanent ice cover where the new Times Atlas shows ice-free conditions and the emergence of new lands...We do not know why this error has occurred, but it is regrettable that the claimed drastic reduction in the extent of ice in Greenland has created headline news around the world. There is to our knowledge no support for this claim in the published scientific literature."

The scientists note that the Greenland ice sheet is losing mass due to climate change, saying:

"We do not disagree with the statement that climate is changing and that the Greenland Ice Sheet is affected by this."

However, the Greenland ice loss is not anything like the rate claimed by the Times World Atlas team. In the letter to the Times, the scientists note:

"It is... crucial to report climate change and its impact accurately and to back bold statements with concrete and correct evidence"

The BBC reports that a HarperCollins spokesperson has suggested that the new map is based on information from the US National Snow and Ice Data Center (NSIDC). The NSIDC make numerous data sets available on their website , and it's not clear whether the Atlas team just meant that they based their work on NSIDC measurements. It seems fair to say that the reaction of UK polar scientists to the story suggests it's unlikely that the World Atlas team consulted closely with scientific experts.

It's unclear what methodology the Atlas team used to plot ice retreat, but scientists we spoke with speculated that the cartographers might have confused the thickness of the ice with its elevation. This would have led to mangled results, as the ground beneath the ice sheet is uneven, and in places the ice cap sits on top of mountain ranges.

We asked the Atlas team for more details of their methodology. We'll update the blog post when they respond.

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