A world plan to fight global warming goes into force on Wednesday, feted by its backers but rejected as an economic millstone by the US and Australia.

After years of delays, the 141-nation Kyoto protocol formally starts at midnight New York time (0500 GMT) with celebrations in the ancient Japanese city of Kyoto where it was signed in 1997.

The pact is the first legally binding plan to tackle climate change, building on a scheme launched at an Earth Summit to stabilise greenhouse gas emissions at 1990 levels by 2000, a goal that was not met.

But it excludes until at least 2012 major developing nations India, China and Brazil, which comprise more than a third of the world's population.

Kyoto aims to put brakes on rising temperatures widely blamed on human emissions of heat-trapping gases that may spur ever more hurricanes, floods and droughts and could drive thousands of species of animals and plants to extinction by 2100.

Sea levels are also expected to rise, threatening low-lying islands and coastal cities.

Some environmental groups were planning protests outside US embassies during the day to underscore Washington's isolation on climate policy.

Kyoto backers say rich nations are probably the main cause of a 0.6C rise in world temperature since the Industrial Revolution and so should take the lead by cutting use of fossil fuels and shifting to cleaner energy such as wind and solar.

PHOTO CAPTION

Japanese wear polar bear costumes on a street in Tokyo to rejoice that the Kyoto Protocol has come into effect, February 16, 2005. (REUTERS)