The European Commission President, Jose Manuel Barroso, said there must be a common European response to climate change.
He also said new policies were needed 'to face a new reality' to make Europeans' energy supplies more secure.
The commission called on developed nations around the world to cut emissions of gases blamed for global warming by 30% by 2020, saying the EU would go beyond its unilateral target if others followed suit.
The EU's new target is more ambitious than an existing one for an 8% cut in emissions in the 2008-2012 period adopted by the 15 members of the EU before its 2004 enlargement.
However, several countries are already struggling to meet that original target.
The commission also said 20% of EU power should come from renewable sources, such as wind, by 2020.
That compares with an existing target of 12% by 2010, which the union is likely to miss.
Today's proposals must be approved by EU governments.
An EU official said the commission was likely to approve a proposal that biofuels should account for 10% of fuel used by vehicles by 2020.
