Barack Obama 'vows major greenhouse gas emissions cuts'

Mr Obama will collect his Nobel prize on 10 December

President Barack Obama is to pledge to cut greenhouse gas emissions in the US in several stages, including a 42% cut by 2030, US officials say.

The offer will be made at December's UN climate talks in Copenhagen, which Mr Obama will attend. He does not plan to be there for the crucial last days.

The talks will try to draw up a new global climate treaty to supplant the 1997 Kyoto Protocol.

UN climate chief Yvo de Boer said his attendance could be vital for a deal.

"It's critical that President Obama attends the climate change summit in Copenhagen," he told journalists.

So far more than 60 world leaders have said they will attend the summit.

Observers say the attendance of such figures as Mr Obama will raise hopes for action on climate change, although the talks are not expected to result in a new treaty.

Mr Obama will be in the Danish capital on 9 December en route to Oslo to pick up his Nobel Peace Prize, but does not plan to return for the key last stages of the summit, which runs from 7-18 December.

The decision, which is expected to be formally announced later in the day, follows intense speculation about whether the US president would go to Copenhagen.

Climate bill stuck

Officials said the US would pledge a 17% cut in emissions by 2020, 30% by 2025 and 42% by 2030.

Delegations from 192 countries will be attending the summit.

Leaders saying they will attend include UK Prime Minister Gordon Brown, French President Nicolas Sarkozy and Brazilian President Luis Inacio Lula da Silva.

Hu Jintao, president of the world's largest polluter, China, is yet to commit to attending.

The US is the second largest polluter after China.

Mr Obama has made climate change a major priority for his administration, but a bill to cut US emissions is currently stuck in the Senate and is not expected to pass before the end of the year.

Correspondents say most nations have given up hope of a legally binding treaty because of uncertainty about the US position.