Including the UK’s contribution, the fund now stands at $9bn with 13 countries on board including the USA ($3bn), Japan ($1.5bn) and France ($1bn).
Energy 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.
“From protecting low-lying islands and coastal settlements from the impact of rising sea levels to helping farmers struggling with lower crop yields caused by the weather effects of climate change – British aid can save lives.
“Along with the UK, other major economies such as the US, Japan, Germany and France have made substantial pledges and I urge other countries to be equally ambitious.”