Environment ministers from 180 countries are taking part in the final stage of an international conference in Argentina to try to push for agreement on ways to combat global warming.

Reports from the conference suggest that key differences remain.

Groups of experts and officials have spent the last 10 days in Buenos Aires trying to work out how to reduce the world's emissions of greenhouse gases, thought to be a major contributor to climate change.

Britain's Deputy Prime Minister, John Prescott, said the negotiations would have to be taken slowly if they were to succeed.

Differences emerge

At issue is the implementation of the 1997 Kyoto protocol, which would enforce strict limits on emissions of carbon dioxide and other greenhouse gases.

Differences have emerged between industrialised and developing nations over the best way forward.

Large developed nations such as the United States have said they want voluntary commitments from developing countries to cut their greenhouse gases, as well as flexibility on implementation before pushing for ratification of the Kyoto protocol.

There are also arguments over implementing a US-backed plan to let industrialised countries trade in allowances to emit greenhouse gases so that they can meet their targets.

The US fears that having to make significant cuts in its emissions will have an adverse impact on the economy, leading to job losses.

It has so far refused to ratify the Kyoto accord, under which industrialised countries agreed to cut their production of greenhouse gases to 5.2% below their 1990 level by 2008-2012.

Climate protocol 'dead on arrival'

Opponents of the Kyoto protocol in the US Congress have warned that there is no chance of it being approved unless significant changes are made.

"As this treaty stands now, it will not be ratified by the US Senate. It's dead on arrival," said Republican James Sensenbrenner.

Environmental activists are seriously concerned at the lack of progress in efforts to tackle global warming.

"People are concerned that the meeting is back to the old dynamic that occurred in Kyoto between the north and south," says Michael Oppenheimer of the Environmental Defence Fund.

The Buenos Aires conference is due to end on Friday.