European leaders are expected to commit their countries to tough new emissions targets at a European Union summit focused on tackling global warming, BBC reports.
German Chancellor Angela Merkel, who will chair the summit, says Europe must lead the fight against climate change.
In Brussels, EU leaders are expected to commit to cutting carbon emissions by 20% by 2020 compared to 1990 levels.
But how this burden will be shared is still subject to argument, as are plans to set renewable energy targets.
In the space of little over a year, climate change and what to do about it has shot to the top of the EU's agenda, says the BBC's Jonny Dymond in Brussels.
Across Europe leaders have been stressing the urgency of action - but now they have to make good on all the talk, he says.
'Not easy'
Mrs Merkel said that if EU leaders approved ambitious targets, it would step up the pressure on other countries to follow their lead.
At a G8 summit later in the year, which she will lead, she said she would be able to say: "Europe has taken an important step of its own and now others - the USA, China, India and the major developing countries - naturally must follow."
It is thought EU leaders may agree to a deeper cut of 30% in emissions by 2020 if other developed and emerging nations, notably the US, India and China, join in.
"It won't be easy, but that's why the EU should make commitments now and take this pioneering position," Ms Merkel told Britain's Financial Times newspaper.
"The necessity to combat climate change and to reduce our energy dependency, coupled with the fact Kyoto is running out, have concentrated minds."
The Kyoto Protocol on greenhouse gas emissions is due to expire in 2012, and lead signatories want a new, tougher version to follow on.
Nuclear question
How a 20% or 30% cut will be achieved is likely to be the focus of lively debate in Brussels.
Poorer Eastern European countries, which are more dependent on heavy industry and carbon-heavy coal, say they will struggle to make the investment in wind farms and solar power necessary to meet the targets.
A European Commission proposal - that 20% of EU energy consumption should be met by renewable sources by 2020 - is therefore thought less likely to be adopted at the two-day summit.
France, which depends heavily on nuclear power, is opposed, saying that, too, should be considered a clean source of energy.
The EU was urged to take global leadership of the issue by the former US vice-president and environmental activist Al Gore, who was also in Brussels.
"I'm trying to get my country to change its policies, but in the meantime the European Union is absolutely key to helping the world make the changes it must," he said.
EU leaders will also consider how to secure and diversify the continent's energy supply in the future, and reduce demand.
(BBC News, 08/03/2007)