Global warming could lead to a 4C rise in temperatures in this generation if it remains unchecked, according to a new study from British scientists.

The study, prepared for the Department of Energy and Climate Change (DECC ) by the Met Office, claims that climate change is an imminent threat.

Unveiled today at Oxford University, it says that if greenhouse gas emissions are not cut then there could be a 4C rise by 2060, some areas such as the Arctic and western and southern Africa seeing leaps of 10C.

Richard Betts from the Met Office Hadley Centre said: 'We've always talked about these very severe impacts only affecting future generations, but people alive today could live to see a 4C rise.

A spokesman for the DECC said: 'The Met Office Hadley Centre research shows that if emissions continue to rise unchecked, it is likely that global warming could exceed 4C by the end of this century.

'A rise of this scale would have serious consequences for the global community with food security, water availability and health all being adversely affected.

'This report illustrates why it imperative for the world to reach an ambitious climate deal at Copenhagen which keeps the global temperature increase to below 2 degrees'.

The study updates a 2007 report by the Intergovernmental Panel on Climate Change (IPCC), which predicted the globe could warm by 4C at the turn of the century if greenhouse gas emissions continue to rise.

But a more severe scenario, with emissions and temperatures rising further because of more intensive fossil fuel burning, was also listed by the IPCC, although this was not considered realistic.

'People will say it's an extreme scenario, and it is an extreme scenario, but it's also a plausible scenario', he said.

'That scenario was downplayed because we were more conservative a few years ago. But the way we are going, the most severe scenario is looking more plausible', Mr Betts told the Guardian.

He added: 'It's important to stress it's not a doomsday scenario, we do have time to stop it happening if we cut greenhouse gas emissions soon'.

A 4C rise in pre-industrial levels could threaten the water supply of half the world's population, swamp low coasts, and wipe out up to half of animal and plant species, and according to scientists.

The Met Office report warns a 4C average would mask more severe local impacts: the Arctic and western and southern Africa could experience warming up to 10C.

New satellite pictures released last week revealed huge ice sheets in Greenland and Antarctica are shrinking faster than scientists predicted and in some areas are in runaway melt mode.

Scientists calculated the changes in the height of the vulnerable but massive ice sheets and found them especially worse at their edges.

In some parts of Antarctica, ice sheets have been losing 30ft a year in thickness since 2003, according to the paper published in the journal Nature.

Some of those areas are about a mile thick so still have plenty of ice to burn through. But the drop in thickness is speeding up.

In parts of Antarctica, the yearly rate of thinning from 2003 to 2007 was 50 per cent higher than it was from 1995 to 2003.

The new measurements are based on 50 million laser readings from a Nasa satellite.

The research found that 81 of the 111 Greenland glaciers surveyed are thinning at an accelerating self-feeding pace. The more the ice melts, the more water surrounds and eats away at the remaining ice.