Poznan, Poland  - Waiting for Obama is a prime pastime at this year's UN climate conference.

Until Barack Obama takes the US president's oath of office on January 20, work on a global deal to combat climate change is largely on hold. But his election is cheering negotiators working toward an accord due by next December.

"I am delighted to see that ... Obama is planning ambitious energy and climate policies," Danish Prime Minister Anders Fogh Rasmussen said as the two-week talks opened Monday.

With 190 nations attending and the Bush administration representing the United States one last time, Obama was the missing link at the talks in Poland.

He has vowed to throw out Bush's policies, pledging to bring US emissions of greenhouse gases back to 1990 levels by 2020 and reduce them 80 per cent by 2050.

He wants to slap binding limits on US emissions and emulate the European Union by launching a market in pollution permits to make dirty industries pay.

Matching the announced policy shift for the world's long-time biggest greenhouse-gas polluter is a change of tone.

Obama will not attend the climate talks, but in a shoutout during his first major speech on climate policy last month, he called the UN conference's work "vital to the planet."

For much of the rest of the world, Obama's impending arrival and eight years of strained relations with Bush led to an awkward situation at the talks.

"It's a complicated moment," French climate envoy Brice Lalonde told reporters. "We are lacking an important negotiating team."

"The only thing we try to do is to keep a place warm" for the new US administration, Lalonde said.

To be sure, Europe is calling for deeper, faster cuts in rich- country emissions. At issue are gases - mostly carbon dioxide from the burning of fossil fuels - that scientists say are warming Earth's atmosphere and changing the climate.

The EU has pledged to cut emissions to 20 per cent below 1990 levels by 2020 on its own and by 30 per cent as part of a global deal.

At home, Obama will face a tough range of demands from US states, business groups and lawmakers once he tries to turn his climate plans into reality.

Harlan Watson, the chief US climate negotiator, said a key challenge for Obama is to reach a "fair deal" between competing regional interests in the United States.

"It's not a partisan issue," he told reporters. "It is a difficult issue. I don't think anyone expects it to be done soon."

Some analysts predict that Obama will fail to win congressional approval for US emissions cuts by next December, the self-imposed deadline for an accord at the UN talks.

"That's what we've agreed to," Watson said. "It won't be easy." (dpa)