How bad is polar ice loss?

News reports everywhere are picking up the theme of 'alarm' over the extent of ice cover at the poles.

"‘What we’re seeing is very dramatic,’ said Andrew Fleming, remote sensing manager at the British Antarctic Survey. ‘It’s very worrying.’ Scientists believed the effects were linked to the ‘very strong warming’ at the poles, he said. The Antarctic peninsula has warmed by more than 3ºC in the past 50 years. ‘That’s a staggering rate of warming, and it’s still going up,’ said Mr Fleming." Extract from a report in today's Financial Times

But, as is often the case, the story looks much less alarming when you look at the data for yourself.

Fortunately that's not at all difficult to do. The US 'National Snow and Ice Data Center', supported by NASA and the US National Science Foundation, provides daily and monthly updates of the ice cover at the Poles using satellite microwave imagery. Plots of the data show that the North Polar ice cover trend line is about 4% below the 1979-2000 mean and falling at a rate of about 3% per decade over the period since 1980. The plot of the Southern Polar ice cover trend is, however, about 9% above the mean over the 1979-2000 period and rising at about 5% per decade.

There's no doubt the world has warmed since the 1970s. There's also plenty of evidence that the Northern Hemisphere has warmed more than the Southern. But nothing in the overall picture points to alarming trends. After all, we know that the North Pole has seen periods comparatively free of ice even in historical times. Nor is there any evidence here that the warming has a global character. These data suggest quite the opposite!

But what about the break-up of the ice on one edge of the Wilkins ice shelf that has even the Financial Times retailing alarm from funding-sensitive researchers? It's about one-pixel's worth of ice in the image of the Antarctic above (click the thumbnails). Completely insignificant except that it probably indicates the well-attested fact that the Antarctic peninsular (at the 'foot' of the Southern American cone) is the warmest place in a continent that is otherwise getting icier.

Tags for this entry: climate policy temperature hemisphere alarm antarctic arctic ice