Sunday, September 25, 2011

Global warming

From this week's New Scientist:

Last week the Times Atlas announced that "For the first time, the new edition… has had to erase 15 per cent of Greenland's once permanent ice cover. This is concrete evidence of how climate change is altering the face of the planet forever.”

Glaciologists cried foul, saying the ice is definitely receding, but the 15 per cent figure is wildly inaccurate.

If what The Times Atlas has said were true, something like a metre of sea level rise would have occurred in the past decade. In fact, Greenland has contributed roughly 3 millimetres to sea level in that time.

So what went wrong? The Times Atlas team say they mapped the ice sheet from ice thickness data on the National Snow and Ice Data Center (NSIDC) in Boulder, Colorado website. But NSIDC says its scientists were not consulted. The data are complex and thickness maps are not intended to show the edge of the ice sheet, so it is possible the cartographers misinterpreted the data.

It is interesting how various media sources handled this piece of information. The Daily Mail assured us that the whole publication would have to be pulped, whereas the BBC passed it off as a trivial error with only the statement having to be withdrawn. The truth is somewhere in between. Publisher Harper Collins apologised for not consulting scientists and retracted the 15 per cent figure, but stood by its map, for now. A spokesperson said it may be modified in annual reprints.

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