Critics fear the climate deal may have been undermined by compromises
The European Parliament has backed a package of measures to combat global warming - seen as a key EU initiative.
The plan, agreed by EU leaders last week, sets out how the 27 member states will cut carbon emissions by 20% by 2020, compared with 1990 levels.
With the backing of MEPs, the package - hailed by French President Nicolas Sarkozy as "historic" - becomes law.
But critics say concessions made to some industrial sectors will lessen the package's long-term impact.
Scientists say carbon dioxide emissions need to be cut by 25-40% by 2020 for there to be a reasonable chance of avoiding dangerous climate change.
'Most ambitious proposals'
"We have sealed the climate package," European Parliament President Hans-Gert Poettering said after Wednesday's vote in Strasbourg. The package - first presented by the European Commission in January - went through by a large majority.
The vote followed a year of tough talks between EU member states to secure the agreement.
At last week's summit in Brussels, EU leaders approved the so-called "20/20/20" package to tackle climate change, including concessions to limit its impact on struggling industries.
The measures commit the bloc to cutting carbon dioxide (CO2) emissions by 20% by 2020.
The EU must also raise renewable sources to 20% of total energy use and achieve a 20% cut in energy consumption.
EU Commission President Jose Manuel Barroso said in Brussels that the plans were "the most ambitious proposals anywhere in the world" to tackle global warming.
A central role in reaching the EU's targets is to be played by the Emissions Trading Scheme (ETS), a system for trading CO2 allowances, first launched in 2005. It covers heavy industry and big power plants, but gradually more sectors will be included.
The parliament's chief negotiator on the ETS, Avril Doyle, said the agreement reached with EU governments was "a balanced outcome between preserving the environmental integrity of the proposal and ensuring a level playing field for European industry".
CO2 emissions from sectors outside the ETS, such as road and sea transport, buildings, services and agriculture, currently account for about 60% of all EU greenhouse gas emissions.
The package sets binding national targets for emissions from non-ETS sectors, with an overall target of cutting these emissions by 10% in the period 2013-2020.
Satu Hassi, a Green MEP who took part in the climate negotiations, said agreement on the targets was "a historical achievement", but she cautioned that "the deal allows outsourcing of over half of EU emissions reductions to other countries".
The Conservatives' environment spokesman in the parliament, John Bowis MEP, said it was "disappointing that the ETS has been watered down in key areas, such as the amount of emission allowances to be allocated by auctioning and the complex methodology agreed for allocating free allowances".
"We give two cheers for the climate and energy package," he added.
The Labour group's spokeswoman for climate change, Linda McAvan MEP, described the package as "the first steps on a long road to a low-carbon society".
She said the "concessions" made did not threaten the "environmental effectiveness" of the package.
International aid groups and environmentalists have accused the EU of bowing to the interests of powerful industrial lobbies.
The head of Oxfam's EU office, Elise Ford, said auctioning CO2 permits "is one of the main ways that the EU could have raised enough money to help poor countries adapt to climate change".
"Instead, gifting permits to big business not only evades the responsibility for them creating emissions but takes money directly from the hands of poor people, who have done least to create the problem," she said last week.