World economy faces 'perfect storm'

People had been living beyond their means through the overuse of natural resources and financial credit, he said in the pamphlet Living Within Our Means.

Mr Porritt claims there is a unique opportunity for politicians to simultaneously tackle both the economic and environmental crises the world faces.

"The shock to the system from the near-collapse of our global banking industry has been traumatic - and it's going to get a lot worse before it gets better. Even so, that is nothing compared to the near-imminent collapse of the ecological systems on which we depend - particularly a stable climate," he said. "The best way to get us out of this recession is by putting in place the measures to help us avoid the ultimate recession."

These measures include a Green New Deal, with investment in energy efficiency, renewables and technology such as smart grids, he urged. There also needs to be reform of the economy, with re-regulation of financial markets, green taxes and an end to unsustainable pursuit of growth as an end in itself.

And in the longer term there has to be reinvestment in the world's natural capital, to rebuild and preserve assets such as forests on which humans rely and which have been badly damaged in recent years.

In the pamphlet he warned that despite the UK's Climate Change Act, there was no "serious indicator" that the Government was using the current crisis for a radical rethink of the way we live. But he said there was cause of optimism, not least in the recovery packages put forward by governments which contain measures to promote renewables, energy efficiency and other low carbon technologies.

And although he was critical of corporate social responsibility measures by businesses as a "fig-leaf" to cover up financial and environmental damage, he also said some major companies had made large and serious commitments to cutting emissions.

A new global deal on cutting greenhouse gas emissions, which it is hoped will be agreed in Copenhagen in December, is "absolutely fundamental, it's a prerequisite to anything happening", he said.

But while he said the fears that the recession would drive climate change off the agenda altogether had not be realised, he said there were still concerns that people would be less ambitious and put a higher priority on conventional economic recovery.