We're all toast unless the world cuts carbon emissions to 1988 levels, says 'godfather of climate change'

James Hansen, who is dubbed the 'godfather of climate change', told the U.S. Congress that the world has long passed the 'dangerous level" for CO2 in the atmosphere and needs to get back to 1988 levels.

He said Earth's atmosphere can stay this loaded with man-made carbon dioxide only for a couple more decades without changes such as mass extinction, ecosystem collapse and dramatic sea level rises.

'We're toast if we don't get on a very different path,' said Prof Hansen, director of the Goddard Institute of Space Sciences. 'This is the last chance.'

The scientist first brought global warming home to the public in June 1988 during a Washington heat wave, saying global warming was already here.

Danger: Emmissions from coal-fired power stations needs to be drastically reduced

To mark the anniversary, he testified before the House Select Committee on Energy Independence and Global Warming, where he was called a prophet.

To cut emissions, he said coal-fired power plants that do not capture carbon dioxide emissions should not be used in the United States after 2025, and should be eliminated in the rest of the world by 2030.

That carbon capture technology is still being developed and not yet cost-efficient for power plants.

Burning fossil fuels like coal is the chief cause of manmade greenhouse gases. Hansen said the Earth's atmosphere has got to get back to a level of 350 parts of carbon dioxide per million.

Last month, it was 10 per cent higher: 386.7 parts per million.

Hansen vowed to testify on behalf of British protesters against new coal-fired power plants.

Warning: Jim Hansen, a leading researcher on global warming, waits to give a briefing on global warming

Protesters have chained themselves to gates and equipment at sites of several proposed coal plants in England.

'The thing that I think is most important is to block coal-fired power plants,' Hansen said.

'I'm not yet at the point of chaining myself, but we somehow have to draw attention to this.'

The year of Hansen's original testimony - 1988 - was the world's hottest year on record. Since then, 14 years have been hotter, according to the National Oceanic and Atmospheric Administration.

Two decades later, Hansen spent his time on the question of whether it is too late to do anything about it. His answer: There still is time to stop the worst, but not much time.

'We see a tipping point occurring right before our eyes,' Hansen said. 'The Arctic is the first tipping point, and it's occurring exactly the way we said it would.'

Hansen, echoing work by other scientists, said that in five to ten years, the Arctic will be free of sea ice in the summer.