European Union leaders have agreed on a common negotiating position for the United Nations climate summit in Copenhagen in December.
They say developing nations would need 100 billion ($US148 billion) per year by 2020 and would pay their "fair share", conditional on other nations.
This is expected to be 22 - 50 billion per year for the EU. The BBC reports details will be sorted out later by a working group. Initial funding will be voluntary.
Nine poorer members of the EU have threatened to block the deal unless richer nations contributed more to the overall sum.