By John Vidal / The Guardian

Arctic sea ice is set to reach its lowest ever recorded extent as early as this weekend, in “dramatic changes” signalling that man-made global warming is having a major impact on the polar region.

With the melt happening at an unprecedented rate of more than 100,000 sq km a day, and at least a week of further melt expected before it begins to reform ahead of the northern winter, satellites are expected to confirm the record – currently set in 2007 – within days.

“Unless something really unusual happens we will see the record broken in the next few days. It might happen this weekend, almost certainly next week,” Julienne Stroeve, a scientist at the US National Snow and Ice Data Centre in Boulder, Colorado, told the Guardian.

“In the last few days it has been losing 100,000 sq km a day, a record in itself for August. A storm has spread the ice pack out, opening up water, bringing up warmer water. Things are definitely changing quickly.”

Because ice thickness, volume, extent and area are all measured differently, it may be a week before there is unanimous agreement among the world’s cryologists (ice experts) that 2012 is a record year. Four out of the nine daily sea ice extent and area graphs kept by scientists in the US, Europe and Asia suggest that records have already been broken.

“The whole energy balance of the arctic is changing. There’s more heat up there. There’s been a change of climate and we are losing more seasonal ice. The rate of ice loss is faster than the models can capture [but] we can expect the arctic to be ice-free in summer by 2050,” said Stroeve.

“Only 15 years ago I didn’t expect to see such dramatic changes, no one did. The ice-free season is far longer now. Twenty years ago it was about a month. Now it’s three months. Temperatures last week in the arctic were 14C, which is pretty warm.”

Read more from The Guardian: http://www.guardian.co.uk/environment/2012/aug/23/arctic-sea-ice-record-low