World governments have pledged a total of up to $9.3 billion to fund climate adaptation and mitigation in developing countries.
The Green Climate Fund (GCF) was created as a vehicle for developed countries to provide developing nations with finance for projects to tackle climate change.
Organisers of the fund held its first "pledging conference" in Berlin today, to act as a forum for countries to announce their contributions. Some had already done so, including Japan, which promised $1.5 billion at the G20 talks last weekend.
Over 20 countries pledged up to $9.3 billion, including $3 billion from the US, $1 billion from Germany and $1 billion from France. The UK has pledged $1.1 billion (£720 million). The money will come from existing funds earmarked for international climate work under its commitment for 0.7% of gross national income to fund overseas development assistance.
Energy and climate change secretary Ed Davey said: "The poorest and most vulnerable on the planet are already suffering the effects of climate change and it's our moral duty to act."
The UK has a seat on the fund's governing board and its 24 members will decide on, and supervise, expenditure. The UK's pledge is dependent on the board confirming the accrediting bodies, which will receive the funds, and agreeing the criteria for investment.
The World Bank will manage the fund's assets as the interim trustee after the fund starts spending next year.
Mary Creagh MP, Labour's shadow international development secretary, criticised the UK's pledge for being a re-announcement of existing funds. The Guardian reported that the prime minister, David Cameron, was keen not to appear to be giving new money to overseas aid on the same day as the Rochester and Strood by-election in case it handed political ammunition to Ukip.
Creagh added: "As David Cameron braces himself for more Tory defectors to Ukip it has exposed how bitterly divided the Conservative party is on climate change.
Jonathan Grant, director of sustainability and climate change at consultants PwC, said: "While there is some debate whether the money would be better spent in the UK rather than abroad, it is clear from the IPCC's latest report that we will need to do both."
Climate impacts overseas, such as damage from extreme weather, can be much more significant for the UK economy than impacts at home, according to a report published last year by PwC.
Providing developing countries with sufficient financial resource to tackle climate change is critical to the intergovernmental negotiations on a new international agreement to curtail greenhouse-gas emissions, as developing countries have previously been reluctant to agree to reduce their emissions until they are convinced that industrialised nations will support them.
Hela Cheikhrouhou, executive director of the fund said: "The result of today's capitalisation of the GCF is foremost an unmistaken sign of trust-building."
The next round of negotiations of the United Nations Framework on Convention Climate Change begin in Lima, Peru in December.