Leading scientists warned a US conference on climate change at the weekend that the rate of global warming has been seriously underestimated.
Christopher Field of the Carnegie Institution for Science told the annual meeting of the American Association for the Advancement of Science that carbon dioxide emissions have been growing at 3.5 per cent a year since 2000, up sharply from the 0.9 per cent per year in the 1990s.
'It is now outside the entire envelope of possibilities' considered in the 2007 report of the International Panel on Climate Change (IPCC), he said on Saturday.
The IPCC and former vice-president Al Gore received the Nobel prize for drawing attention to the dangers of climate change.
The largest factor in this increase is the widespread adoption of coal as an energy source, Mr Field said. 'Without aggressive attention, societies will continue to focus on the energy sources that are cheapest and that means coal.'
Past projections for declines in the emissions of greenhouse gases were too optimistic, he added. Nowhere had emissions declined between 2000 to 2008.
Carbon dioxide and other gases added to the air by industrial and other activities are blamed for rising global temperatures, increasing worries about possible major changes in weather and climate.
Anny Cazenave of France's National Centre for Space Studies told the meeting that improved satellite measurements show that sea levels are rising faster than had been expected, threatening low-lying regions.
She added that the problem was uneven, with the fastest rises measuring at about one centimetre per year in parts of the north Atlantic, western Pacific and the Southern Ocean surrounding Antarctica.
Other researchers said that currently favoured methods of curbing carbon emissions through the use of biofuels may even backfire.
Michael Coe of the Woods Hole Research Centre explained that demand for biologically based fuels has led to the growing of more corn in the United States, but that meant that farmland had been switched from soya beans to corn.
But there was no decline in the demand for soya, he said, meaning other countries, such as Brazil, increased their soya bean crops to make up for the deficit.
In turn, Brazil has created more soya-bean fields by destroying tropical forests, which tend to soak up carbon dioxide.
Instead, the forests were burned, releasing the gases into the air.