Copenhagen - Scientists are gloomy; economists are more upbeat. Such was the bottom line of an epic, three-day international congress of climate change experts that ended here yesterday.

At the congress, it seemed that all the scientists had to share with their peers was bad news, but a number of economists saw the climate crisis rather as an historic opportunity to reorganize the world economy and develop new, clean and job-creating activities.

At the opening of yesterday's session, Lord Nicholas Stern, former chief economist for the World Bank, added his own dose of gloom by saying that his now-famous report on the risks of global warming, written for the British government in 2006, had underestimated them. "The reason is that emissions are growing faster than we thought, the absorption capacity of the planet is less than we thought, the probability of high temperatures is likely higher than we thought, and some of the effects are coming faster than we thought," he explained.

Stern called for $400 billion in extra public funding -- 20 percent of a global package of $2 trillion -- to be made available for the 'green component' of the world stimulus over the next year or two.

Several other economists also sent messages of growth promotion via support for green investments. These included Terry Barker, director of the Centre for Climate Change Mitigation Research of the University of Cambridge. "The current global financial crisis must be seen as a timely stimulus to tackling climate change, not a hindrance," Barker said.

Obama's 'green New Deal' praised

"If all G-20 countries adopted a 'green New Deal' similar to the one proposed by President Obama, the world economy would be greatly strengthened, especially the sectors producing low-carbon technologies," he went on. "But global coordination is critical. Any single country's New Deal may fail if its extra demand for goods and services is met with imports. If we act together, everyone's exports will increase and we can recover employment much more quickly."

Barker went a step further, saying, "Where many current calculations get it wrong is in the assumption that more stringent [climate mitigation] measures will necessarily raise the overall cost, especially when there is substantial unemployment and underuse of capacity as there is today."

He added: "There is some evidence that harder greenhouse gas targets and regulation may actually increase benefits through improved innovation and distribution of low-carbon technologies and increased revenues from taxes or permits. These revenues can be spent to further support new technology and to lower other indirect taxes, ensuring the fiscal neutrality of these measures."

Stern and most of the economists at the conference strongly supported the cap-and-trade approach to reducing emissions. Stern said it "has many advantages -- including a much greater quantity and certainty than taxation would give you, and allows funds to cross borders in a way which couldn't happen through [carbon] taxes."

In an interview, Stern said he was impressed by the Obama administration's climate policy, though he noted that Europeans are questioning the credibility of Obama's proposed emissions reductions, which they believe push the more difficult cuts too far into the future.

"Barack Obama has said that, on the way to an 80 percent cut [in U.S greenhouse gas emissions] by 2050, he would aim at returning to 1990 levels by 2020. This would mean that the U.S. would accomplish its entire 80 percent in three decades instead of six. Is this credible? So that's the challenge. Europe has to recognize where the United States is and show some understanding, but the U.S. has to go a bit further."

'Major migrations' will be part of social disruptions

As the congress wound down, members produced a list of six key conclusions that will be included in a report to U.N. decision-makers prior to December's climate change protocol negotiations in Copenhagen.

On climate trends, the conference noted: "Given high rates of observed emissions, the worst-case IPCC scenario trajectories (or even worse) are becoming a reality. There is a significant risk that many of the trends will accelerate, leading to an increasing risk of abrupt or irreversible climatic shifts."

On social disruption, it said: "Societies are highly vulnerable to even modest levels of climate change, with poor nations and communities particularly at risk. Temperature rises above 2° C will be very difficult for contemporary societies to cope with, and will increase the level of climate disruption for the remainder of the century."

Major migrations will be part of these potential social disruptions. On this topic, one of the conference's key speakers, John Schellnhuber of the Potsdam Institute for Climate Impact and Research, proposed that rich countries accommodate future climate refugees on their soil according to their historical share of greenhouse gas emissions.

"So, if the USA produces 25 percent of emissions, it would have to accommodate 25 percent of the world's climate refugees," he said, to hearty applause from some conference participants.