WASHINGTON - As more than 100 nations gather at The Hague this week to hammer out the final details of the international treaty to reduce heat-trapping greenhouse gases, the convention faces a political quagmire that could prevent its successful implementation worldwide.

Unless countries resolve their differences and reach an agreement at the meeting in The Hague, November 13 to 25, scientists say the consequences could be disastrous. Most climate experts believe global warming is caused by mostly carbon-based gases emitted when fossil fuels, like oil, gas and coal are burned.

Already these gases have been blamed for heating the deep oceans, fracturing Antarctic ice shelves and fuelling more intense El Niños.

To deal with these threats industrialised nations - despite strong opposition from powerful oil, coal and gas industries fearing for their bottom-line - negotiated an international agreement in 1997, known as the Kyoto Protocol.

Named for the Japanese city where it was drawn up, the treaty requires that industrialised countries reduce their emission by five to seven percent below 1990 levels by 2008 to 2012.

The Protocol requires the ratification of at least 55 of the countries that signed the Convention, including the industrialised countries of the Organisation of Economic Co-operation and Development (OECD), which in 1990 accounted for more than half of carbon dioxide emissions, one of the main greenhouse gases.

Yet the agreement has yet to be ratified by most of the signatories. Since its inception, the treaty has been plagued by political resistance from the United States, the world's largest emitter of greenhouse gases.

While the administration of US President Bill Clinton signed the treaty, the US Senate refuses to ratify the Kyoto Protocol and has put language into appropriations bills that forbids the government from spending money to comply with the Kyoto Protocol.

In 1997 the Senate approved a resolution that the administration should not sign any climate change agreement that would ''result in serious harm to the economy of the United States.''

US lawmakers argue that the treaty is unfair because it does not require developing countries to commit to binding targets at this time. Despite the advice of most of the world's scientists, many US lawmakers are even saying they are not convinced that humans are responsible for global warming.

''The uncertainties and complexities of the climate change question have become more and more apparent as we look at it more scientifically,'' said Republican Senator Chuck Hagel from Nebraska in September.

A coalition of powerful oil and gas industries echoed this view in a multi-million dollar advertising campaign against the treaty.

But most of the developing economies of Latin America, Asia and Africa argue that the wealthy industrialised nations should make the first move toward reducing emissions since they are responsible for the bulk of the emissions already in the atmosphere.

Just before a conference on climate change was held in September in the French city of Lyon as a preparation for The Hague meeting, the Group of 77 plus China, made up of developing countries, restated their firm opposition to new commitments.

While the United States is not on track to meet the Kyoto targets, the European Union says it is on target to meet its commitment, if its member states do what they have promised in the fields of renewable energy - like wind and solar - and taxation on fossil fuels. However, several analysts stated in October that this was unlikely.

The Controversy

The contentious issues left to be hammered out at The Hague include the treaty's so-called ''flexible mechanisms'' - emissions trading, clean development and joint implementation - and whether there should be a limit to the extent they can be used to account for a country's Kyoto target.

While the European Union believes there should be a cap on trading, the US administration argues it should be able to use flexible mechanisms to meet all of its reductions.

Most international environmental groups, including Greenpeace and Friends of the Earth, view the flexible mechanisms as loopholes that will allow industrialised nations to meet their obligations without cutting their own emissions.

They argue that international carbon trading - either between industrialised nations or between industrial and developing nations - cannot work since carbon is emitted from millions of sources all over the world and is impossible to monitor.

Further complicating the situation is the variation in emissions trends since the 1990 base year. Owing to economic collapse, Russia's 1995 emissions were 29 percent below 1990 levels, and Ukraine's 1997 emissions were down by 49 percent. Meanwhile, in 1997 the European Union's emissions were only four percent below while US emissions were 11 percent above 1990 levels.

Because of these discrepancies, countries such as Russia and Ukraine under the Protocol have been granted carbon emission credits potentially worth billions of dollars annually. This then would allow the United States and other major emitters to meet most of their reduction commitment by purchasing credits from this region for reductions that have already taken place.

''Trading of 'hot-air' would undermine the legitimacy of this system, making it more an arena for political horse-trading than a market mechanism,'' argues Hillary French, vice-president of research at the Worldwatch Institute in Washington.

At The Hague, countries will also debate how to harness the ability of forests to absorb 'greenhouse' gases. The United States, Japan, Canada and Australia are pushing for the inclusion of emission credits from the forests or tree plantations.

But environmentalists point out there is no scientific precision in measuring the ability of forests to absorb carbon gases, and no way to know that preserving one forest area will not lead to the clear-cutting of another.

''By and large this storage of carbon in forests would happen anyway and if it is counted it would permit vast increases in fossil fuel use,'' says Bill Hare, climate policy director of Greenpeace International.

Environmentalists are also worried about another of the flexible mechanisms under Kyoto called the Clean Development Mechanism (CDM), which permits industrial nations to buy inexpensive reductions in developing countries.

A typical CDM plan might involve selling China technology to make its coal cleaner, or a US coal-burning utility could pay to expand or preserve carbon-absorbing forests in Costa Rica.

Ross Gelbspan, a long-time US-based author on climate change issues, says the CDM plan is inequitable since it would allow industrial nations to buy limitless amounts of cheap emission reductions in poor countries and to bank them indefinitely into the future.

This would mean that when developing nations eventually become obligated to cut their own emissions, they will be left with only the most expensive options, says Gelbspan.

"This clearly constitutes a form of environmental colonialism," he says.

In early October, more than 130 environmental organisations also criticised the US proposal for the CDM plan that would allow nuclear power plants to receive emission credits.

Groups, including Public Citizen, Greenpeace and Friends of the Earth, say the US stance amounts to the transfer of a harmful outdated technology to Asia, Latin America and Africa.

''Western nuclear companies, unable to get contracts at home due to safety, environmental and cost concerns, would be attempting to dump their unwanted and failing technology on developing countries,'' says a letter the organisations sent to US President Bill Clinton.

At the preliminary meeting in Lyon in September, several leaders from indigenous tribes, from Panama to the Philippines, urged industrialised nations to reduce their own emissions instead of relying on the flexible mechanisms.

By switching to renewable energy and reducing government subsidies and tax breaks for fossil fuels, many nations could meet or exceed their Kyoto commitments, they argue.

''What is needed is a fundamental change in philosophy,'' says Antonio Jacanamijoy, an indigenous leader from the Amazon region of Colombia.