But, observed Dr Pachauri, economic incentives are needed to drive any technological transformation.
"Technology alone will not be enough," he told BBC News, "and in any case, technology has a clear connection with government policy.
"Incentives... must come from taxes or a carbon price."
Catherine Pearce, international climate campaigner with Friends of the Earth UK, said there was now no economic excuse for inaction.
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"This report shows that many affordable technologies and effective policies are readily available to tackle climate change," she said.
"By introducing measures and investment that will stimulate sustainable renewable energies and energy efficiency, governments can help to achieve cuts in global emissions by 50% by 2050. Without this, we face devastating consequences."
Reuters/Financial Times:UN says global warming halt affordable
By Reuters May 04 08:56:36
Humans need to make sweeping cuts in greenhouse gas emissions over the next 50 years to keep global warming in check, but it need cost only a tiny fraction of world output, a major UN climate change report said on Friday.
The Intergovernmental Panel on Climate Change (IPCC), in the third of a series of reports, said keeping the rise in temperatures to within 2 degrees Centigrade would cost only 0.12 per cent of annual gross domestic product.
”It’s a low premium to pay to reduce the risk of major climate damage,” Bill Hare, a Greenpeace adviser who co-authored the report, told Reuters after the culmination of the marathon talks which ran over their four-day schedule.
”It’s a great report and it’s very strong and it shows that it’s economically and technically feasible to make deep emission reductions sufficient to limit warming to 2 degrees,” he said. ”It shows that the costs of doing this are quite modest.”
To keep within the 2 degree threshold which scientists say is needed to stave off disastrous changes to the world’s climate, emissions of carbon dioxide need to drop between 50 and 85 per cent by 2050, the report said.
However, technological advances – particularly in producing and using energy more efficiently – meant that such targets were within reach, the report said.