G7 leaders in their joint communique reaffirmed the collective developed countries goal to jointly mobilise $100 billion a year from public and private sources, through to 2025.
The Group of Seven nations have agreed to increase their climate finance contributions and meet an overdue spending pledge of $100 billion a year to help poorer countries, calling on other developed countries to join the effort.
In a copy of a joint communique following a weekend meeting of the world's seven largest advanced economies, the G7 said: "We reaffirm the collective developed countries goal to jointly mobilise $100 billion/year from public and private sources, through to 2025, in the context of meaningful mitigation actions and transparency on implementation."
"Towards this end, we commit to each increase and improve our overall international public climate finance contributions for this period and call on other developed countries to join and enhance their contributions to this effort."
Tackling the climate challange
British environmentalist David Attenborough told G7 leaders on Sunday that tackling climate change was now as much a political challenge as it was a scientific one.
"We know in detail what is happening to our planet, and we know many of the things we need to do during this decade," he said in a recorded video address.
"Tackling climate change is now as much a political and communications challenge as it is a scientific or technological one. We have the skills to address it in time, all we need is the global will to do so."
'Protecting our planet'
"Protecting our planet is the most important thing we as leaders can do for our people," Johnson said on Sunday in a statement.
"As democratic nations, we have a responsibility to help developing countries reap the benefits of clean growth through a fair and transparent system. The G7 has an unprecedented opportunity to drive a global Green Industrial Revolution, with the potential to transform the way we live."
It gave no details or numbers for the new commitments.
2009 plan derailed by pandemic
Developed countries agreed at the United Nations in 2009 to together contribute $100 billion each year by 2020 in climate finance to poorer countries, many of whom are grappling with rising seas, storms and droughts made worse by climate change.
That target was not met, derailed in part by the coronavirus pandemic which forced the British government to postpone the United Nations' Climate Change Conference (COP26) until this year.
G7 leaders are also expected to set out action to cut carbon emissions, including measures such as ending almost all direct government support for the fossil fuel energy sector overseas and phasing out petrol and diesel cars.
"The natural world today is greatly diminished. That is undeniable. Our climate is warming fast. That is beyond doubt. Our societies and nations are unequal and that is sadly is plain to see," said British naturalist David Attenborough, the people's advocate for COP26.
Attenborough will address leaders via video message on Sunday.
He said the question for 2021 was whether the world was on the verge of destabilising the planet.
"If that is so, then the decisions we make this decade - in particular the decisions made by the most economically advanced nations - are the most important in human history."
Greenpeace UK's executive director, John Sauven, described the track record of rich nations in honouring their commitments as "dismal" and Johnson of failing to take "real action to tackle the climate and nature emergency".
"While commitments to provide more support to developing nations are absolutely vital, until they cough up the cash, we're taking nothing for granted," he said in a statement.