An ice-free Arctic Ocean has happened before
By Paul Homewood
A bit of common sense from Matt Ridley:
When the Arctic loses all its sea ice one summer, will it matter?
My Times column on how the Arctic sea ice has melted in late summer before, between 10,000 and 6,000 years ago:
The sea ice in the Arctic Ocean is approaching its annual nadir. By early September each year about two thirds of the ice cap has melted, then the sea begins to freeze again. This year looks unlikely to set a record for melting, with more than four million square kilometres of ice remaining, less than the average in the 1980s and 1990s, but more than in the record low years of 2007 and 2012. (The amount of sea ice around Antarctica has been increasing in recent years, contrary to predictions.)
This will disappoint some. An expedition led by David Hempleman-Adams to circumnavigate the North Pole through the Northeast and Northwest passages, intending to demonstrate “that the Arctic sea ice coverage shrinks back so far now in the summer months that sea that was permanently locked up now can allow passage through”, was recently held up for weeks north of Siberia by, um, ice. They have only just reached halfway.
Meanwhile, the habit of some scientists of predicting when the ice will disappear completely keeps getting them into trouble. A Nasa climate scientist, Jay Zwally, told the Associated Press in 2007: “At this rate, the Arctic Ocean could be nearly ice-free at the end of summer by 2012.” Two years later Al Gore quoted another scientist that “there is a 75 per cent chance that the entire north polar ice cap, during the summer months, could be completely ice-free within five to seven years” — that is, by now.
This year Professor Peter Wadhams of Cambridge University has a new book out called Farewell to Ice, which gives a “greater than even chance” that the Arctic Ocean will be ice-free next month. Not likely.
He added: “Next year or the year after that, I think it will be free of ice in summer . . . You will be able to cross over the North Pole by ship.” The temptation to predict a total melt of the Arctic ice cap, and thereby get a headline, has been counterproductive, according to other scientists. Crying wolf does not help the cause of global warming; it only gives amusement to sceptics.
Read the full article here.