European Union leaders have agreed an offer to put on the table at global climate talks in Copenhagen in December after healing a rift over how to split the bill.
Developing countries will need €100 billion a year by 2020 to battle climate change, and up to €50 billion of this will have to come from the public purse in rich countries worldwide, rather than industry, leaders said.
The two-day EU summit secured a complex negotiating mandate for the Copenhagen talks to find a successor to the Kyoto Protocol, which expires in 2012.
"We managed to reach an agreement on climate finance," Swedish prime minister Fredrik Reinfeldt said. "The EU now has a strong position in view of Copenhagen."
Success in Copenhagen is likely to hinge on money. Developing countries say they will not sign up to tackling climate change without enough funds from rich nations, which bear most of the responsibility for damaging the atmosphere by fuelling their industries with oil and coal over decades.
Developing countries might use such funds to adapt their agriculture or find new sources of water in drought zones.
A formula will be calculated that "takes fully into account the ability to pay", the text of the agreement said. Leaders fell short of agreeing a concrete formula now and handed that job to a new working party.
"I think this is a breakthrough that takes us forward to Copenhagen," British prime minister Gordon Brown told reporters.
The EU pledged to strengthen planned emissions cuts to 30 per cent below 1990 levels by 2020 if other countries made similar commitments. But they put on hold earlier plans to come up with "fast start" financing for developing nations in the three years before any new climate deal takes effect.
East European countries said the summit had settled a rift over how to split the EU's portion of the bill in a way that would not hurt their economies as they recover from crisis.
"We consider this a success for Poland," said the Polish minister for Europe, Mikolaj Dowgielewicz. "We want to develop quickly. We don't want to become the museum of folklore of eastern Europe."
The main achievement on the first day of the summit yesterday was an agreement opening the way to ratification of the Lisbon Treaty.
Under the deal, the leaders accepted Czech president Vaclav Klaus's demands for an opt-out from a rights charter attached to the Lisbon Treaty to shield the Czech Republic from property claims by ethnic Germans expelled after the second World War.
An aide said Mr Klaus was satisfied with the decision, which met his condition for signing the treaty. Ratification by the Czech Republic, the only EU state holding out against signing, now depends on its constitutional court rejecting a legal challenge in a ruling expected next week. "The road to ratification now stands open," Swedish prime minister Fredrik Reinfeldt said.
The leaders said they did not discuss who would be the EU president, but former British prime minister Tony Blair's hopes faded when his candidacy failed to secure the blessing of European socialists who are his ruling Labour Party's allies.
The post is now more likely to go to a centre-right leader, especially as centre-right parties dominate the European Parliament and form a majority among EU leaders.
No front-runner has emerged but possible contenders include Dutch prime minister Jan Peter Balkenende, former Finnish prime minister Paavo Lipponen and Luxembourg prime minister Jean-Claude Juncker. Former Fine Gael taoiseach John Bruton has also thrown his hat in the ring.