The plan would cut greenhouse gases by less than half the amount set in the climate treaty, the Kyoto Protocol.

We think it is better to settle for a bad deal now than to have to accept something still worse a few months on

John Lanchbery, RSPB

And key participants accept it only because they believe any possible alternative would be even worse.

One UK official said: "In some respects, this draft may be slightly less good than the deal the European Union rejected at the last round of negotiations in The Hague last November.

To some degree, it is a political fix. Lots of things present us with difficulties, but we are prepared to go along with it as a package."

The talks are a resumption of the failed Hague negotiations, and are intended to finalise the workings of the Kyoto Protocol.

That requires industrialised countries to cut their emissions of six main greenhouse gases by an average of 5.2% below their 1990 levels by 2012.

But the compromise proposal, drafted by the conference president, Jan Pronk, would deliver far less than that.

Rally outside Bonn talks

John Lanchbery, of the UK's Royal Society for the Protection of Birds, has followed the climate talks for years.

He told BBC News Online: "This won't lead to 5% cuts - it will mean reductions of barely 2%."

Modest targets

Many climate scientists say the protocol's targets are themselves so modest that they amount to little more than a declaration of intent by the world to get round to tackling climate change at some future date.

They say cuts in emissions of 60-70% will be needed in the course of this century, and perhaps by its mid-point, in order to avoid very serious destabilisation of the climate.

So cuts of about 2%, now the subject of line-by-line negotiation on this last day of the conference, seem barely worth arguing about.

The reason why the European Union and other groups here are prepared to sign up, despite their real misgivings, lies elsewhere: in Washington DC.

Morocco next

President Bush announced in March that the US would not ratify Kyoto, but would come up with counter-proposals of its own.

Those are now expected before the next round of climate talks, to be held in late October in Morocco.

And it is the conviction that the US proposals would wipe Kyoto off the map and replace it with something even worse (from their point of view) that is driving the EU and its allies to give assent - through gritted teeth - to Mr Pronk's plan.

The US, present here but not negotiating, is to them the spectre at the feast.

Mr Lanchbery said in June: "I think there is a good chance of an agreement in Bonn.

Whether it will be good for the environment is another matter."

On Sunday, he told BBC News Online: "This is not a good proposal for the environment, and if it is agreed we certainly won't be happy with it.

But the more time passes, the worse things get.

We think it's better to settle for a bad deal now than to have to accept something still worse a few months on, driven by the Americans."

It is far from certain the Pronk compromise will finally win acceptance.

If it fails, it will probably serve as a muted elegy to the Kyoto Protocol.