Britain has pledged up to 720 million pounds ($1.13 billion) on Thursday to a United Nations fund to help poor nations cope with global warming, the government said.

The contribution is equivalent to around 12 percent of the Green Climate Fund (GCF), whose total funds currently stand at around $9 billion, based on pledges from 13 countries, it said.

At the weekend, the United States pledged $3 billion and Japan promised $1.5 billion. Germany and France have pledged $1 billion each.

Britain's contribution will come from existing funds earmarked for international climate work.

High-level fund donors are meeting in Berlin on Thursday. The U.N. has set an informal target of raising $10 billion this year.

Italy, Canada and Australia are among the major donors yet to announce pledges.

The cash is intended to help emerging economies curb their greenhouse gas emissions and adapt to changes such as heatwaves, mudslides and rising sea levels, widely seen as vital to unlock a U.N. climate deal meant to be agreed in late 2015 in Paris.

The GCF is a major part of a 2009 plan to increase financial flows from public and private sources to help developing nations tackle climate change to $100 billion a year by 2020.