"I can confirm that the objectives remain the same, the calendar remains the same, now it's up to [us] to find solutions for those countries that expressed concerns.

Jose Manuel Barroso, the president of the European Commission (EC), said: "We are not going to let up on the battle against climate change, no question of choosing against combating the financial crisis and climate change."

Sarkozy's remarks follows concerns expressed by environmental groups that France might use the financial crisis as an excuse to water down the EC proposal on climate change.

EU's targets

Failing banks, plunging stock markets and warnings of recession have pushed climate change down the agenda of the two-day summit, which began on Wednesday, but no one challenged the key commitment to reduce 20 per cent of greenhouse gas emissions by 2020 from 1990 levels.

The EC also wants the EU to have 20 per cent of renewables in the energy mix and having 20 per cent of energy savings.

The 27-nation EU bloc aims to lead the world in battling global warming, mindful of UN predictions of more extreme weather and rising sea levels.

But Eastern European countries and some of Europe's traditional industries say the plan is too costly in light of the crisis.

Some members were defensive, calling in a joint letter to leaders backing Sarkozy's move, to recognise their economic difficulties.

Veto threats

On Wedensday, Donald Tusk, the Polish prime minister, threatened to use his veto unless more was done to shield his country's coal-based economy from the impact of the measures.

Some EU leaders said their economies could not afford to tackle climate issues [GALLO/GETTY]
"If there is no other solution, we will use the possibility of a veto," he said.

"The stakes are high. But the determination of Poland and eight other countries is starting to have its effects."

His Italian counterpart, Silvio Berlusconi, also wielded a veto threat to demand more time and fewer burdens on industry, calling the whole idea of trading in the right to pollute as "ridiculous".

"I am ready to use our veto powers," he told reporters.

But there were some leaders at the summit who linked the climate change battle to efforts to reduce the bloc's dependence on oil and gas imports, saying that rescuing the economy could go hand in hand with saving the environment.

Gordon Brown, the British prime minister, said Europe's move to a low-carbon economy would help reduce costly and volatile oil imports and protect it from sudden disruptions to supply.

"If the last year showed anything, it is that we must deal with the climate change problem, because oil is less affordable than it was, because energy security is more important than it was," he said.