By Richard Black
Environment correspondent, BBC News website
China's plan aims to re-heat the economy with green flames
Economic stimulus packages being drawn up around the world show governments are taking the environment seriously, the UN's top climate official believes.
Yvo de Boer, executive secretary of the UN climate convention, cited plans to boost growth by investing in renewable energy and public transport.
He said leaders "could not afford to fail" on climate change.
Other speakers at a Globe International meeting in London suggested the packages needed to be much bolder.
Some observers have suggested that the world's financial troubles would reduce the chances that governments would invest in measures that could lower carbon emissions, such as renewable energy, energy efficiency and public transport.
But China's 10-point plan, unveiled in November, will target more than $100bn at increasing efficiency, expanding rail networks and "environmental improvements".
US President Barack Obama's plan, scheduled for a Congressional vote this week, will aim to double capacity for alternative sources of energy like wind, solar, and biofuels over the next three years.
Speaking at the Globe meeting, former UK environment minister Elliott Morley said that if European governments followed these leads, that could mean a total of $1.5 trillion being targeted at green reforms.
The economic crisis could be "just the thing" to galvanise governments into making the deep radical changes to set the world's economies on a more environmentally sustainable track, he added.
Mr de Boer, who heads negotiations within the UN climate convention, said developments in Beijing and Washington were signs that governments were using the economic troubles as a window of opportunity for reforming their economies.
"The high emissions, debt-driven, resource intensive model is dying," he said.
"The impacts of climate change would put the final nail in its coffin."
Limits to growth
Other speakers at the Globe event were less impressed by the stimulus packages rolled out across the world.
Anders Wijkman, a Swedish MEP, said they were not bold enough to drive the transition to a green economy.
Yvo de Boer is leading moves to reach a new climate pact in December
He cited the dilution of the EU's climate and energy package during December's European Council summit as an example.
"Half of the 20% (reduction in greenhouse gas emissions by 2020) can be done through offsetting," he said.
"If the ultimate goal is to bring emissions down to zero, then this just postpones the day of action."
Mr Wijkman said the world's economic and environmental crises were linked, with both stemming from the unsustainable, unthinking rush to use resources - a theme taken up by other speakers.
"Unlimited growth on a planet with finite resources cannot go on forever," said Eberhard von Koerber, co-president of the Club of Rome.
Reforming economies along sustainable lines, he said, "does not imply a reduction in the rate of growth - only that the growth will be achieved differently".
In the 1930s depression, Mr de Boer related, Franklin D Roosevelt had used his inauguration speech to proclaim that "the only thing we have to fear is fear itself".
That was not the case now, he said.
"The shadow of climate change grows darker each year. But the only thing we have to fear now is the fear to act."
Governments are aiming to agree a new global deal on climate change at the next UN climate convention summit in Copenhagen in December.
Globe - Global Legislators for a Balanced Environment - is a group of parliamentarians which supports "ambitious political leadership" on issues of environment and energy.
It convened this meeting in preparation for the G20 summit in April, which the UK will chair.
Including many of the world's larger and more influential developing nations, speakers said the grouping could play a vital role in achieving a new deal within the UNFCCC.