Many developing countries have been arguing for a "twin track" approach, whereby countries with existing targets under the Kyoto Protocol (all developed nations except the US) stay under that umbrella, with the US and major developing economies making their carbon pledges under a new protocol.

BBC: Copenhagen climate summit negotiations 'suspended'

Sweden, France, Germany and the UK are just about on track to achieve the 8 percent reduction to which the EU committed itself in the Protocol.

CNN: Kyoto: The next generation

Everywhere there are TVs with split screens showing the two tracks of negotiations: one track for everyone, and the other for those who signed up to the Kyoto Protocol 12 years ago.

BBC: Harrabin's Notes: Inside Copenhagen