Global warming? No, actually we're cooling

There has been a 60% increase into the amount of ocean covered with ice compared to this time last year, the equivalent of almost 1.6-million square kilometres.

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 has led some scientists to claim 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. Several years ago the BBC predicted that the Arctic would be ice-free by 2013. Despite the original forecasts, major climate research centres now accept there has been a "pause" in global warming since 1997.

The original predictions led to billions being invested in green measures to combat the effects of climate change. The changing predictions have led to the UN's climate change's body holding a crisis meeting, and the IPCC is due to report on the situation in October.

But the leaked report is said to show that the governments that fund the IPCC are demanding 1500 changes to the Fifth Assessment Report - a three-volume study issued every six or seven years - as they claim its current draft does not properly explain the pause.

The extent to which temperatures will rise with carbon dioxide levels and how much of the warming over the past 150 years, a total of 0.8C, is down to human greenhouse gas emissions are key issues in the debate.

The IPCC is "95% confident" that global warming has been caused by humans - up from 90% in 2007 - according to the draft report.

However, US climate expert Professor Judith Curry has questioned how this can be true as rather than increasing 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.

Professor Anastasios Tsonis, of the University of Wisconsin, said: "We are already in a cooling trend, which I think will continue for the next 15 years at least. There is no doubt the warming of the 1980s and 1990s has stopped."

The IPCC maintains its climate change models suggest a pause of 15 years can be expected. Other experts agree that natural cycles cannot explain all the recorded warming.