Meeting in Brussels for a two-day gathering, EU heads of state and government will seek to hammer out a united energy strategy aimed at diversifying sources while reducing pollution.

In the run-up to the meeting, EU leaders have cranked up the rhetoric about the need for tough action to tackle global warming, although some environmentalists say that proposed targets do not go far enough.

German Chancellor Angela Merkel, who will host European leaders for the first time under Germany's EU presidency, stressed the urgency of their task by warning that Europe was at an "important crossroads."

"If we act decisively now, we have a chance of effectively counteracting the dangers of climate change," she said in her invitation to the summit.

Merkel told the British Financial Times newspaper on Wednesday that she wanted "Europe to take a 'pioneering lead' on meaningful green initiatives."

Merkel was seconded by former US Vice President, Al Gore who recently picked up an Oscar for his documentary on the ravages of global warming.

Speaking to reporters on a visit to Brussels to address a conference on biofuels, Gore said a European lead on the issue was vital.

"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 change it must," he said.

Securing energy supplies

British Prime Minister Tony Blair said that Europe should not only show leadership on combating climate change, but also beef up the security of energy supplies while opening the market to more competition.

"I think there is the real possibility of showing how Europe can lead the debate on climate change, on energy security, and on deregulation in the interest of a more competitive European economy," Blair said on Tuesday in London.

EU leaders are expected to endorse plans to cut carbon dioxide (CO2) emissions by 20 percent by 2020, from 1990 levels, and by 30 percent if other developed and emerging economies, particularly China and India, join them.

The European Union produces about 14 percent of the world's
greenhouse gas emissions while the United States, the world's
largest polluter, produces some 25 percent.

Although the summit is expected to provide a show of unity, tensions are brewing under the surface over the role of nuclear energy and the use of renewable energy sources.

One of the liveliest debates is expected on whether to set a binding target of renewable energy sources meeting 20 percent of Europe's energy needs by 2020, after foreign ministers failed to reach an agreement on Monday.

Environmentalists: "It's not enough"

Although Europe is leading efforts to combat climate change, some environmentalists warned that the EU leaders are not aiming high enough.

"The EU's energy action plan ... will fall a long way short in making Europe's energy more sustainable unless targets for both renewable share and reducing greenhouse gases are raised and tightened," said Friends of the Earth climate campaigner Jan Kowalzig.

Energy policy has climbed to the top of the EU political agenda over the last year as oil price spikes and cuts in gas and oil supplies from Russia have spurred the bloc to forge a common strategy to meeting their needs.

However, despite the growing importance attached to energy, the EU has struggled to hammer out a common approach, with member countries often putting national interests first, much to the frustration of the European Commission.

Increasing competition

Such is the case with a European Commission idea to inject greater competition into the EU energy market with plans to make large, integrated gas and power companies split their generating and distribution networks.

Leaders are likely to send the plan back to the drawing board with France and to a lesser extent Germany opposed to the idea, which could cause a major shake-up of French and German energy groups.

The summit comes amid a shifting European political landscape with Italian Prime Minister Romano Prodi emerging shaken from a recent crisis, British Prime Minister Tony Blair increasingly a lame duck, and looming French presidential elections in April and May.

It will also be French President Jacques Chirac's last chance to leave his mark on EU policy-making after nearly 12 years in office fiercely defending French interests during meetings with EU leaders.

Looking ahead as Germany chairs the Group of Eight industrial nations this year, Merkel will likely want to take the conclusions of this week's meetings into the G8 summit in Heiligendamm, Germany in June.