A cold Arctic summer has led to a record increase in the ice cap, leading experts to predict a period of global cooling.

There has been a 60 percent increase in the amount of ocean covered with ice compared to this time last year, they

equivalent of almost a million square miles.

In a rebound from 2012’s record low an unbroken ice sheet more than half the size of Europe already stretches from the Canadian islands to Russia's northern shores, days before the annual refreeze is even set to begin.

The Northwest Passage from the Atlantic to the Pacific has remained blocked by pack-ice all year, forcing some ships to change their routes.

A leaked report to the UN Intergovernmental Panel on Climate Change (IPCC) seen by the Mail yesterday, has led some scientists to claim that the world is heading for a period of cooling that will not end until the middle of this century.

If correct, it would contradict computer forecasts of imminent catastrophic warming. The news comes several years after it was predicted that the arctic would be ice-free by 2013.

Despite the original forecasts, major climate research centres now accept that there has been a "pause" in global warming since 1997.

The leaked documents show that governments who fund the IPCC are demanding 1,500 changes to the Fifth Assessment Report as they claim its current draft does not properly explain the pause.

The IPCC says it is “95 percent confident" that global warming has been caused by humans - up from 90 percent in 2007 - accord-ingto the draft report.

However, US climate expert Prof Judith Curry has questioned how this can be true as that rather than increasing in confidence, "uncertainty is getting bigger" within the academic community.

Long-term cycles in ocean temperature, she said, suggest the world may be approaching a period similar to that from 1965 to 1975, when there was a clear cooling trend.