warming treaty raises a hurdle that may snarl negotiations at the United Nations climate conference this week. The 27-nation bloc said it accounts for about 11 per cent of global emissions and that it can’t act alone on emissions blamed for damaging the environment. Limits under the Kyoto Protocol expire next year. Japan, Russia and Canada have ruled out more commitments under that pact.

“We would only be politically able to move ahead into a second commitment period of the Kyoto Protocol if there is at least a road map forward with others saying when they are going to come into the climate fight,” Artur Runge-Metzger, the European Commission’s lead negotiator, said on Sunday at a press briefing opening the talks in Durban. The comments, from Kyoto’s strongest supporter in the industrial world, mark the bloc’s biggest set of preconditions and complicate talks to rescue the only international treaty on cutting greenhouse gases.

Developing countries oppose binding targets for themselves and view the continuation of Kyoto’s goals for richer nations as the key to the fight against climate change — even without Japan, Russia and Canada onboard. They’re concerned the EU’s plan, calling for a treaty coming into force by 2020, as a way of delaying action.

The UN’s diplomat leading the talks said the question of Kyoto’s future is the most important one facing delegates, though she wouldn’t discuss where the EU position would drive the talks.

The US has signalled it opposes the EU plan. Todd Stern, the state department’s climate envoy, told reporters in a November 18 briefing that it’s “premature” to make promises about the legal form of a climate agreement before seeing its contents. US officials are scheduled to brief journalists in Durban on Monday.

The EU timeline may also jar with findings by the International Energy Agency and three UN bodies this month. IEA chief economist Fatih Birol had said that with current energy policies, the door is closing to a future in which temperature gains are constrained to 2 degrees Celsius (3.6 degrees Fahrenheit) since industrialisation, a goal adopted by UN envoys at last year’s talks in Cancun, Mexico.

The US says it won’t agree to a binding accord unless all emitters are included. China and India, which had no commitments under Kyoto, have become two of the world’s three top polluters since the pact was agreed in 1997.