New York  - The so-called green economy is booming across the globe and the market for environmental products and services is likely to double by 2020, according to a UN study released Wednesday.

Efforts to combat climate change have already created millions of new "green jobs" and opened up fresh sectors for economic growth as countries around the world invest in new technologies. UN officials urged governments to keep going despite a global economic crisis.

"The world will spend hundreds of billions of dollars in the next 12 months on stabilizing the global economy. Imagine for a moment if some of the stimulus packages could be targeted towards ... investing in the new economy of the 21st century," Achim Steiner, head of the UN Environment Programme, told reporters.

The UN report, released on the sidelines of an annual UN summit marking a new year for the General Assembly, projected the global market for "green" products and services would double to 2.74 billion dollars by 2020.

The study also warns that many poorer countries, who have suffered most from the effects of climate change, are being left out of the boom. Shifting developing economies from dirty to clean industries is as crucial for reducing global warming as it is for pulling many developing regions out of poverty, the UN said.

In a separate move on global warming Wednesday, the UN launched a new initiative to help developing countries combat deforestation, which contributes about 20 per cent of greenhouse-gases entering the atmosphere.

Nine countries, including Indonesia, Congo and Vietnam have agreed to take part. Norway has pledged 35 million dollars to start off the programme. (dpa)