Soot from the burning of fossil fuels contributes far more to global warming than has been thought. But, unlike carbon dioxide (CO2), soot lingers only a few weeks in the air, so cutting emissions could have a significant and rapid impact on the climate.

If soot emissions were eliminated, more than 1.5 million premature deaths from soot inhalation could be prevented worldwide each year, reports the Journal of Geophysical Research.

According to a new study led by Mark Z. Jacobson of Stanford University in the US, the quickest, best way to slow the rapid melting of Arctic sea ice is to reduce soot emissions from the burning of fossil fuel, wood and dung.

His analysis shows that soot is second only to CO2 in contributing to global warming.

But climate models to date have mischaracterised the effects of soot in the atmosphere, he said, according to a Stanford release.

'Because of that, soot's contribution to global warming has been ignored in national and international global warming policy legislation,' said Jacobson, director of Stanford's atmosphere/energy programme.

'Controlling soot may be the only method of significantly slowing Arctic warming within the next two decades,' he added.

Reducing soot output would start slowing the pace of global warming almost immediately, the study concluded.