Clean energy investment needs to more than triple to $515bn a year to prevent the proportion of greenhouse gases in the atmosphere reaching levels considered by scientists to risk runaway heating of the planet, the World Economic Forum has said in a report prepared by research group New Energy Finance .

The enormous investments that are required in renewable energy sectors such as solar and wind energy – $515bn is estimated in the report – need to be made between now and 2030. Clean energy investments were $155bn in 2008, up $30bn on 2004 but still far below the level needed to combat climate change.

“Clean energy opportunities have the potential to generate significant economic returns,” the World Economic Forum said in a statement accompanying the report.

Climate change experts including Yvo de Boer of the United Nations Framework Convention on Climate Change haveurged governments to use part of the fiscal stimulus packages currently being prepared to invest in clean energy.

Representatives of all the conerned world governments will meet in Copenhagen later this year to try to reach a deal to dreate the next stage of the Kyoto process, which sets targets for cutting carbon dioxide emissions.