Updated: Copenhagen could enter extra time

The Copenhagen Summit could go into extra time as world leaders continue to push for a compromise deal to curb global carbon emissions.

European Union environment commissioner Stavros Dimas told reporters that the UN organisers had asked world leaders to plan to stay overnight in Copenhagen and attempt to secure a deal over the weekend.

"The Secretary-General of the United Nations (Ban Ki-moon) has asked people not to leave tonight," Dimas told reporters, adding that he remained confident a workable agreement could be reached. "I cannot imagine 120 leaders going back to their countries with empty hands. Everyone expressed commitment to fight climate change. OK, do it."

However, British officials refused to confirm whether they had been asked to stay at the talks and a spokeswoman for the UN said that no request for leaders to remain in Copenhagen had been made. Danish newspaper Berlingske Tidende also reported that the talks will have to be wrapped up be early evening.

It remains to be seen how many leaders will stay beyond the scheduled close. Many leaders are meant to leave Copenhagen early this evening and White House officials have long insisted that president Obama will depart today to begin his holiday in Hawaii.

Venezualan president Hugo Chavez said earlier today that he would not sign a deal that had been forced on poorer nations and was leaving. Other developing countries had also been pushing for a firm deadline to the talks amid fears that their position would be weakened by late-night arm twisting by richer nations.

Confusion also continued to surround the current state of the negotiations this afternoon with conflicting reports on the liklihood of a compromise deal being reached.

Associated Press reported that president Obama was holding a meeting with leaders from the UK, Australia, France, Germany and Japan, fuelling speculation that rich nations were continuing to push for a compromise deal to be reached. Separate reports claimed that virtually all the parties involved were united in pushing China for it to shift its position.

Meanwhile, Reuters reported it had obtained a leaked draft of a so-called "Copenhagen Accord", which contained a pledge that "increase in temperatures should be below 2 degrees", but appeared to drop any commitment that a binding treaty should be signed next year.

Green groups responded angrily to the leaked text with Joss Garman of Greenpeace condemning it as "so weak as to be meaningless".

"It's more like a G8 communique than the legally binding agreement we need," he added. "It doesn't even include a timeline to give it legal standing or an explicit temperature target. It's hard to imagine our leaders will try to present this document to the world and keep a straight face."

Despite the dire state of negotiations, some optimism remained that a compromise deal could be brokered after US president Barack Obama and Chinese premier Wen Jiabao met for around an hour and reportedly made progress towards an agreement on key issues.

Mark Kenber, international policy director at think tank the Climate Group, said that a "deal is still there to be had".

"We've seen there's genuine commitment to an agreement, with countries reiterating their most ambitious national pledges," he said. "If these can be brought together, I think a political agreement is possible, perhaps in the next few hours. The dividing issues now appear to be more procedural than substantive."

There was also some good news for green businesses in the series of speeches this morning from Obama, Wen, and Indian prime minister Manmohan Singh.

Each of the addresses were regarded as disappointing by many observers at the summit, who criticised them for containing no new substantive commitments. But in a move that will serve to boost investor confidence in clean technologies, each leader reiterated that their domestic commitments to curb emissions and transition to a lower carbon economy was unconditional and would continue regardless of whether an international deal is reached or not.