Most influential was a study commissioned by the British government and conducted by former World Bank Chief Economist Nicholas Stern. Its estimates on the economic toll of global warming were so eye-poppingly high that even those once skeptical of doom and gloom tales are paying heed.

"I'd be considerably less dismissive of this sort of study today than I might have been 10 or 20 years ago," said David Simpson, an environmental economist who has worked at the US Environmental Protection Agency.

"There have been scary environmental and resource stories for centuries, but it seems to me that prudence is dictating that we pay more attention," said Simpson, also a professor at Johns Hopkins University.

Simpson's change of heart is not uncommon. Jeremy Siegel, a famously conservative economist and professor of finance at the University of Pennsylvania's Wharton School of Business, recently summarized his shifting perception.

"For years, I believed that 'Global Warming' was an issue where the science was contradictory and the consequences were far enough in the future to have little or no impact on current markets," he admitted. "Not anymore."

Still, many experts are hopeful nature could bounce back with a little help from its human friends.

"I think nature is so fundamentally resilient that if we can turn around the harm that we're doing, things can and will return to normal," said Mark Spalding, president of the Ocean Foundation, a Washington-based conservation group.

But time is of the essence.

Doing something about global warming now may seem costly, but the expense grows exponentially the longer the problem is allowed to fester. The Stern report estimates the net future benefits of taking strong action against climate change this year alone could add up to a massive US$2.5 trillion.

Unfettered, temperature shifts could cost more than World War Two, and take a greater toll on the economy than the Great Depression, according to Stern's findings.

Another recent report from the WWF conservation group said by 2050 humanity would need two planets' worth of natural resources every year if current consumption trends held.

"If every other economy consumed at the same level that California or the United States does, we wouldn't have enough planet to go around," Spalding said.

BUSINESS AS USUAL?

Despite these stark assessments, the United States has declined to rejoin the Kyoto Protocol, which obliges 35 rich nations to cut carbon emissions. President Bush pulled the United States from the agreement in 2001, citing fears that it could hurt economic growth.

However, many economists are beginning to look more critically at how to make growth more sustainable, and some see a role for government to make up for what Stern called "the greatest market failure the world has seen."

"The current 'price' of the environment does not reflect the fact that many of the natural resources are scarce and finite," said Norbert Walter, chief economist at Deutsche Bank. "As long as the market does not provide these price signals, the state has to regulate, using its environmental instruments."

In that vein, there has been a significant push to make corporations accountable for any environmental destruction they cause. One effort, known as environmental accounting, would force firms to account for their use of natural resources.

Under this arrangement, a tree chopped down by a lumber company would not simply be a capital gain for the firm, but also a liability for its stock of natural resources.

While such "sustainability reporting" is growing in acceptance among large firms like General Electric Co. and Wal-Mart Stores Inc., critics say the mechanism lacks the sort of specific goals that could help mitigate risks to the natural world.

"Although around two-thirds of companies report some interaction with investors on sustainability matters, many reports still lack the hard targets and forward-looking information that makes required reading for analysts," according to a report published on Thursday by the United Nations Environment Program and Standard and Poor's.

Another green corporate initiative is carbon trading, where firms buy and sell credits for reducing emissions, thereby generating a financial incentive to cap pollutants.

But frustration with existing conservation efforts has prompted some specialists to question the growth imperative altogether, blaming the world's ills on an obsession with ever greater material gain.