The agreement came at the end of the Climate Change Conference in Bonn. But environment groups accused several countries of undermining the talks by looking for loopholes behind the scenes.

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A 1997 deal, reached in the Japanese city of Kyoto, commits the industrialised world to an overall 5% cut in greenhouse gas emissions from 1990 levels by the year 2012.

Germany's environment minister Juergen Trittin said that despite objections from Saudi Arabia and other key oil exporters, the majority of participating countries wanted the agreement to take effect in the next three years.

"For those who want to delay the Kyoto protocol entering into force, we say to you: 'You can stay out of this process if you want, but you can no longer stop it'."

Both Europe and Japan said for the first time they would ratify the Kyoto protocol by 2002. But the US, the world's biggest polluter, said it would not go along with the deadline. The US Congress wants more action from developing countries.

Meanwhile, the Worldwide Fund for Nature, has accused the US and Australia, Japan and Canada of political schizophrenia.

It said that while their ministers were calling for progress in tackling global warming, their civil servants were trying to widen a loophole allowing them to measure emissions in a different way, thus appearing to reduce them without actually doing so.

Fish are dying

Most scientists agree that greenhouse gases - from car exhausts or burning coal, for instance - are to blame for the warming of the Earth's surface.

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They warn that this will lead to flooding in coastal areas, devastating drought in dry areas and disruption of fragile ecosystems.

Low-lying and small island countries which stand to suffer most from global warming said they were disappointed by the lack of progress.

The government representative from the Caribbean island of St Lucia said the delegates were fiddling while the world burned.

Cyclones are increasing in frequency and intensity in the Caribbean, according to government representatives.

They say the fishing industry is also suffering as bacteria harmful to fish are starting to thrive in warmer ocean temperatures.

Officials from the 173 nations at the Bonn conference agreed to meet in a year's time in the Hague in the Netherlands.