More and more evidence is accumulating that a clean and green economy is most likely to deliver a more secure, prosperous and less tumultuous future for humanity, according to World Wildlife Fund.

WWF International Director General Jim Leape was commenting on?the release of the major United Nations Environment Program (UNEP) report Towards a Green Economy which shows that appropriate policies and relatively modest redirections of global investment flows could grow the global economy at equivalent or greater levels than current forecasts.

The more sustainable economy would also be less affected by scarcities and disruption than the existing, resource-depleting, high carbon "brown" economy, the report said.

"UNEP's report demonstrates that a clean and green development path can produce growth and employment while cutting costs and reducing the risks associated with business as usual," Mr Leape said.

"Conventional economic thinking, GDP measures of growth and conventional corporate accounting will take us crashing headlong into the Earth's limits.

"We need to move now to recognize the fundamental importance of the natural capital upon which the entire economy depends, and ensure that conservation of that capital is brought into the heart of public and corporate decisionmaking."

"The way of the future is now being shown by the countries and companies that are now moving strongly to invest in renewable energy sources and better stewardship of forests, fisheries, and other resources."

Mr Leape noted that the UNEP report identified greening energy supplies as the area needing the largest level of investment. That mirrors findings of WWF's recent Energy Report which found that it was both possible and imperative to switch to a 100 per cent renewably powered world by 2050.