( dpa ) - They have promised to fight climate change, and now they have to deliver: that is the challenge the European Union's executive is set to present to its member states on Wednesday.
In March, the EU's 27 political leaders agreed to cut the bloc's emissions of the gases which create global warming to 20 per cent below 1990 levels by 2020, with legal penalties for those who fail to comply.
On Wednesday, the European Commission - the Brussels-based EU body which drafts the bloc's laws - is set to suggest how member states should meet that target and similarly binding goals for the use of renewable energy and plant-based bio-fuels.
But even before its launch, the so-called "climate and energy package" has provoked criticism from governments, industry and environmentalists alike.
On Tuesday, French President Nicolas Sarkozy warned that his state - one of the EU's heaviest users of nuclear power - "could not accept" any law obliging it to use more than 20 per cent of renewable energy, since it already had a relatively low level of emissions.
EU members are arguing about how much each member state should cut emissions and boost its use of renewable energy to meet the EU-wide targets.
Industry and trade unions have warned that the legislation could drive industry out of Europe to countries with less strict rules, and have called for an import tax to make such moves unattractive.
And environmental groups have warned that the drive to use more bio-fuels could lead to deforestation, unrest and rising food prices as farmers clear land and shift production from food to fuel crops.
The legislation at the centre of the storm is a set of proposals drawn up by the commission's environmental and energy departments.
The first calls for a gradual tightening of the rules of the EU's flagship emissions-trading scheme (ETS). It is aimed at making it progressively more expensive for major industries to emit greenhouse gases, thereby encouraging them to invest in "clean" technology.
The second proposal sets out how member states should act to make sure that 20 per cent of the energy they consume comes from renewable sources such as solar power by 2020, and that bio-fuels make up 10 per cent of the transport fuel they burn.
Finally, the commission is set to propose limits for individual member states on emissions not covered by the ETS, and say how those states should share the burden of fighting climate change.
Responding to some of the issues raised by critics, the proposals insist that bio-fuels be produced "sustainably" and say that the commission will analyse world markets in 2011 to make sure that EU firms do not feel unfair pressure from higher-emissions countries.
The package is not only a challenge to the EU's member states: it is also intended to challenge other major economies to follow the EU's lead in tackling climate issues.
EU leaders have already pledged that they would cut emissions by 30 per cent, not 20 per cent, before 2020 if other major economies were to make similar pledges.
While no such economies are directly named, the United States - which has so far resisted calls to impose binding emissions targets - is the most obvious target of this appeal.
Preliminary drafts also say that member states will only get credit for supporting emissions-reduction projects in less-developed countries if they do so in states which ratify an expected successor to the Kyoto Protocol on climate change.
That clause, if approved, would be likely to have an impact on China and India - both growing economies who have so far been key recipients of such support.
With the commission challenging member states to live up to their promise of March 2007, and other states to match the EU's efforts, the fight over the climate and energy package looks set to be a fierce one.