London, Nov 9 : Rich nations must "contribute substantially" to funds that will help developing countries in the global fight against climate change, Finance Minister Pranab Mukherjee said.

"Developed countries will have to contribute substantially. It can be supplemented by carbon market, by private sector, but substantially it will have to come from the developed countries," Mukherjee told journalists Sunday after attending a meeting of finance chiefs from the Group of 20 nations.

"The appropriate forum [for decisions] is the UN Framework Convention on Climate Change," Mukherjee said.

The G20 meeting in St Andrews, Scotland, issued a communique Saturday saying finance ministers will "commit to take forward further work on climate change finance, to define financing options and institutional arrangements".

Richard Dixon, director of WWF Scotland, said: "The G20 finance ministers meeting turned out to be a mostly irrelevant side-show on the way to the talks in Copenhagen in a month's time."

Mukherjee said countries meeting in Copenhagen in December must not veer from "the basic principle of Common But Differentiated responsibility" in attempts to find a successor agreement to the Kyoto Protocol on climate change, whose first commitment period runs out in 2012.

Under this principle, wealthy developed countries, who are primarily responsible for causing climate change, are to pledge most of the funding needed to help developing countries fight climate change.

"Funding will be required to have access to clean technology at affordable cost," Mukherjee said.

"Another aspect is what will be the level of the finances, and over what period of time," Mukherjee said, adding the minimum figure mentioned by the World Bank is $80 billion per year with a five percent annual escalation until 2030.(IANS)