European Commission president José Manuel Barroso has urged Nicolas Sarkozy to stick to his guns and force through the Commission's package of environmental targets and legislation during his upcoming stint as EU president.

Sarkozy takes up the presidency in July in the face of strengthening opposition to last month's proposals to cut carbon emissions by 20 per cent and ensure 20 per cent of energy comes from renewables by 2020, which the Commission would like to see formally adopted by early next year.

In an interview with the Financial Times at a meeting in Svalbard, Norway, Barroso said that Sarkozy would have a critical role to play in brokering agreement on the targets between member states.

"I have no doubts about the commitment of Mr Sarkozy," he said. "It will be his responsibility to get agreement among all member states: he will be chairman [of meetings where the targets are discussed]."

He also underlined that the EU's standing as a global leader in the fight against climate change would be at stake throughout the talks. "There are some negotiations going on but I am completely confident that at the end we will get agreement," he said. "The EU leaders unanimously approved [the proposal last March] and it will be respected – if not, it will be a blow to our credibility. "

But despite Barroso's optimism, Sarkozy is set to face a tough balancing act if he is to get all member states to agree to the targets without substantial changes.

Several governments, including Germany and some figures within Sarkozy's own government, have expressed opposition to the targets allocated under the Commission's plan.

Heavy emitting industries have also expressed concerns that the plans to expand the EU's carbon-trading scheme will have an impact on their global competitiveness, prompting strenuous lobbying in Brussels for a watering down of the scheme.