Drastic reduction of carbon emissions may not be enough to avert the damage caused by global warming, according to Rajendra Pachauri , Chief of Intergovernmental Panel on Climate Change (IPCC).
According to a report in The Times, Dr Pachauri proposed that new techniques should be applied to help to mop up atmospheric levels of carbon dioxide (CO2) that have been pumped into the atmosphere from the burning of fossil fuels.
"There are enough technologies in existence to allow for mitigation. At some point, we will have to cross over and start sucking some of those gases out of the atmosphere," he said.
Dr Pachauri raised the prospect of so-called geo-engineering, whereby CO2 is actively stripped from the atmosphere.
A range of techniques have been proposed, including seeding artificial clouds over oceans to reflect sunlight back into space, sowing the oceans with iron ore to boost plankton growth and using carbon capture and storage technology to fix emissions from power stations.
Speaking days before the start of the UN climate summit in Copenhagen, Dr Pachauri, who collected the 2007 Nobel Peace Prize on behalf of the IPCC with Al Gore, said that such a strategy needed to be pursued as a matter of urgency.
About 27 billion tonnes of pure CO2 are pumped into the atmosphere every year - equivalent to 7.3 billion tonnes of pure carbon.
Total atmospheric concentrations of CO2 are now at 387 parts per million, up from an historic average of 180 to 280 ppm.
Even if radical cuts were adopted by world governments in Copenhagen and adhered to, the lowest level at which they could be expected to stabilise is 450 ppm, according to scientists.
To prevent a further temperature rise of more than 2C, emissions would need to be stabilised around that level.