ABC News Online,
Carbon dioxide emissions, the main driver of global warming, could fall 3 per cent worldwide in 2009 due to the global economic crisis, the International Energy Agency (IEA) has said.
This would be the steepest drop in CO2 emissions for 40 years, chief IEA economist Fatih Birol said at a press conference in Bangkok, adding that the average annual growth in global carbon output until now has been 3 per cent.
Dr Birol said this silver-lining drop in carbon pollution was a "unique window of opportunity" for the world to put itself on a path to limit the increase in global temperatures to two degrees Celsius, the scientific threshold for dangerous global warming.
The recession-driven fall would lead to CO2 emissions in 2020 being 5 per cent lower than the IEA forecast from just a year ago, even if no further action is taken to curb global warming, he added.
The IEA estimate is part of its World Energy Outlook report, an excerpt of which was released at UN climate talks underway in the Thai capital.
It outlined how steeply countries would have to cut their carbon emissions over the next 20 years in order fix the concentration of CO2 in the atmosphere at a level that would ensure the two-degree threshold is not crossed.
That level, measured in parts per million, is 450 ppm, according to a benchmark scientific report issued in 2007 by the UN Intergovernmental Panel on Climate Change (IPCC).
"By reducing emissions, the financial and economic crisis has created a window of opportunity to transition the global energy system to a 450 ppm trajectory," said UN climate chief Yvo de Boer in a preface to the new IEA report.
"This gives us a chance to make real progress toward a clean energy future, but only if the right policies are put in place promptly," added IEA Executive Director Nobuo Tanaka in a statement.
"Every year of delay adds an extra $US500 billion ($563 billion) to the investment needed between 2010 and 2030 in the energy sector," he warned.
The climate talks under the UN Framework Convention on Climate Change (UNFCCC) have been stymied for months, and are running out of time to deliver a new global climate treaty at a December conference in Copenhagen.
Rich and poor nations are divided over how to share the burden of cutting greenhouse gases, and who is going to pay for it.
Developed nations are willing to take the lead, but expect emerging giants such as China, Brazil and India to commit to mitigation measures as well, pledges these countries have fiercely resisted.
Rich nations created the problem and should bear the brunt of the responsibility to fix it, the developing countries say.
Economist Dr Birol confirmed that China surpassed the United States as the world's top carbon polluter in 2007, adding that "it will be the same in the future".