As the United Nations climate change summit drew to a close in Bali, environment secretary Hilary Benn stressed the need to secure a deal.

Ministers were on Friday discussing an agreement on reducing global emissions to replace the current Kyoto Protocol, which expires in 2012.

The EU wants binding emissions targets of 25 to 40 per cent by 2020, but the US has signalled a preference for voluntary reductions.

And Benn said: "The hard bargaining has begun. If the negotiation is to be successful, we need two things: we have to accept the science and we have to clear about what every country will contribute."

"There's real desire to get an agreement. The world will not forgive us if we don't."

He told BBC Radio 4's Today programme that "nobody is under any illusions about the importance of the task that we've got".

"And the need to secure a deal which would give us, for the very first time, all the countries of the world committing themselves to a negotiating process to end in 2009, to get a new agreement to replace the Kyoto Protocol.

"[This is] because the science is very, very clear and what we are doing currently is way short of what is needed to prevent dangerous climate change."

"As a world we are consuming the earth's resources as if we had another two spare planets tucked away in the cupboard. We don't, we just have the one," Benn added.

"Everyone's got to play their part - governments, business and each of us as individuals."

The US has been condemned by environmental groups for failing to accept firm cuts.

Friends of the Earth executive director Tony Juniper said: "The US are behaving like first class passengers on a jumbo jet who believe an emergency in economy class does not affect them.

"But if we go down, we go down together and the US needs to realise that very quickly."