Wednesday, September 21, 2011

Fuzzy Science

It's a good rule of thumb, I think, always to be skeptical of scientific studies or discoveries which have political or metaphysical implications.

When, for example, fossilized single-celled organisms are claimed to have been found in meteorites, a discovery which would lend credence to the dogma that evolution of life is inevitable and will occur anywhere that conditions are right, it's wise to wait for further examination by experts to see if they concur that these really are fossilized organisms and not just inorganic artifacts. Likewise with any alleged discovery of remains of a putative link between homo sapiens and ape-like evolutionary ancestors.

Similarly, reports of alarming developments caused by climate change should be taken with a grain of salt until the reports have been subjected to the peer-review process. Often it'll be found that the assertions are either overblown or simply wrong. The case of the Himalayan melting glaciers last year is an example.

Another may be found in a story at NewScientist.com:
Erroneous data about how much ice is vanishing due to climate change are once more at the heart of an explosive controversy. This time, it's not the Intergovernmental Panel on Climate Change, but the venerable Times Comprehensive Atlas of the World that is in the line of fire.

Journalists across the UK received glossy press packs last week for the launch of a new edition. It included a press release declaring that: "For the first time, the new edition […] has had to erase 15 per cent of Greenland's once permanent ice cover – turning an area the size of the UK and Ireland 'green' and ice-free. This is concrete evidence of how climate change is altering the face of the planet forever."

Today glaciologists have been crying foul, saying that the 15 per cent figure is wildly inaccurate.

When New Scientist contacted the Times Atlas team last week to find out where they had obtained the number, they cited the National Snow and Ice Data Centre (NSIDC) in Boulder, Colorado, but were unable to be more precise.

Ted Scambos, the NSIDC's expert on the Greenland ice sheet, says neither he nor his colleagues were consulted in person. "Graduate students would not have made a mistake like this," he told New Scientist. "If what The Times has said were true, something like a meter of sea level rise would have occurred in the past decade."

That is nowhere near what measurements show. "Currently, Greenland is losing mass at about a rate of 150 billion tonnes per year, or about one-third of a millimetre of sea level rise per year," says Scambos. That means in the 12-year period from 1999 to 2011 that the Times Atlas analysed, meltwater from the Greenland ice sheet has contributed roughly 3 mm to global sea level rise – not 1 metre.

In total, the Greenland ice sheet holds enough ice to raise global sea level by about 7 metres, so the loss since 1999 has been less than 0.05 per cent.
Of course, a 3 mm rise in sea level in 12 years is not the same as zero rise, but it's hardly alarming. If the ice continues to melt at that rate then by the end of the century the oceans will be about an inch higher than they were at the beginning of the century. That doesn't seem all that alarming.