Yesterday's announcement by the Department of Energy & Climate Change comes ahead of UN talks on the issue in Paris in December.
Christian Aid's Chief Executive Loretta Minghella said: "We know that without tackling climate change, poverty will be permanent.
"The UK's substantial, multi-year commitment of funds will also help build trust with developing countries in the run up to the climate talks in Paris - trust that has been lacking in previous negotiations."
Announced at the UN's General Assembly in New York, the UK's pledge is to increase its spending by at least 50% to a further £5.8bn of funding from April 2016 to March 2021.
It is designed to help millions of people cope with the impacts of climate change and increase access to clean energy, while supporting global efforts to tackle the emissions that cause climate change.
Energy and Climate Change Secretary, Amber Rudd said: "As well as helping vulnerable countries to reduce their emissions, finance can also help them better adapt to weather extremes and rising temperatures associated with climate change.
"This can increase their resilience, alleviating pressures on natural resources such as land, water and forests, which could lead people to sell their property or migrate."
Ms Minghella added: "This kind of finance is a win-win: it has the potential to bring clean, renewable energy to some of the poorest people in the world and also reduce global carbon emissions.
She also believes the UK's commitment is a challenge to the rest of the world.
"We hope that other countries will follow suit over the coming weeks, ahead of the Paris Summit.
"At those talks, world leaders should also agree on global revenue-raising mechanisms to deliver the new, additional and predictable climate finance that we know will be necessary in the years to come."