Two targets are on the table at the contentious summit on environmental issues – that by 2020 sources such as solar and wind power should account for 20 percent of EU consumption, and that biofuels should make up 10 percent – but whether to set the goals in concrete is a source of deep friction between member states.

With EU leaders meeting March 8, the commission has put its political cards on the table and called for national governments to do the same.

"From Moscow to Washington, they will be watching us to see if we are really credible," said commission president Jose Manuel Barroso. "It is much more credible to have a binding target than an indicative target."

Some member states -- France and several central and eastern European countries -- are opposed to mandatory targets. Paris is seen as key for an agreement, but its compromise of higher targets on low-carbon energy while including nuclear energy is opposed by non-nuclear countries like Ireland and Austria.

Mr Barroso said EU member states should commit to cutting greenhouse emissions by 20 percent by 2020, rising to 30 percent if other developed countries come on board.