A European Union deal last week to step up a fight against global warming could break a deadlock and nudge other big greenhouse gas emitters such as the United States, China and India to do more, experts said.
"It's a very courageous move on the part of the EU," said Yvo de Boer, head of the UN Climate Change Secretariat in Bonn, which oversees stalled UN efforts to negotiate wider curbs on emissions of greenhouse gases beyond 2012.
"It's exactly what developing countries have been calling for. They have been calling on industrialised countries to take the lead" before discussing what they might do to slow their rising emissions, he said.
"It's a chicken and an egg situation. For many industrialised countries, including the US, meaningful engagement by developing countries is critical."
The 27-nation EU set unilateral goals for raising the share of renewable energies, such as hydro or wind power, to 20 per cent of energy use by 2020 from below seven now. The deal came in exchange for flexibility on national contributions.
Leaders at the Brussels summit also agreed last Friday to slash greenhouse gas emissions, mainly from burning fossil fuels, to 20 per cent below 1990 levels by 2020, or 30 per cent if other developed nations follow suit.
"The decision re-establishes Europe's legitimacy and credibility to play a key role facilitating and catalysing a global agreement on climate change," Achim Steiner, head of the UN Environment Programme, told Reuters.
"It shifts the focus onto the G8 summit and to some extent the United States," he said. Host Germany wants the June summit of eight leading industrial nations to focus on climate change.
US President George W. Bush has repeatedly said he will not drop opposition to caps on emissions under the UN's Kyoto Protocol for curbing global warming. He says Kyoto would damage the US economy and wrongly excludes goals for poor nations.
Mr Bush prefers big investments in new technologies such as hydrogen and biofuels. But many US Democrats and some states and cities favour tougher Kyoto-style caps.
"I am quite optimistic that America will join the bandwagon after 2008 because we will have a new president," said Hans Joachim Schellnhuber, head of the German Potsdam Institute for Climate Impact Research.
He said US wider participation was a pre-condition to get developing nations to sign up. The United States is the world's top emitter of greenhouse gases, ahead of China, the EU, Russia, India and Japan.
"In the end China and India will only come on board if the US demonstrates that they are willing to become partners in climate protection," he said, praising the EU deal. He said it would spur new low-polluting industries in the EU.
Mr De Boer estimated that, with the new targets, the EU might invest an extra $15 billion in renewable energies in developing nations by 2020 under a Kyoto deal allowing some emissions cuts to be made abroad.
"This is good news for developing nations," he said.
The EU deal was also the first sign that governments are acting after the world's top climate scientists last month said it was more than 90 per cent certain that human activities had caused most of the warming since the Industrial Revolution.
They predicted rising temperatures, more floods, storms, droughts and rising seas. A British report last year, the most detailed so far of the economics of climate change, said that it would be far cheaper to act now than suffer the consequences.
"The message has got through to the heads of state," said Jennifer Morgan, of the London-based environmental think-tank E3G. "This shows that taking climate change seriously is economically possible in an energy-insecure world."
Under the EU deal, national targets will be set with the consent of member states. EU president Germany added wording to win over states reliant on nuclear energy, led by France, or coal, such as Poland.