This weekend UK prime minister Tony Blair will call for the G8 group of industrialised nations to admit five developing nations to the group in order to tackle climate change and other global issues.

Leaders of the five nations -- Brazil, China, India, Mexico and South Africa - will attend part of this weekend's G8 summit in St Petersburg, Russia.

Blair's government warned on Thursday that climate change could devastate much of Africa, negating any benefits from aid packages agreed at last July's G8 meeting in Scotland.

But it remains to be seen what prominence climate change will have at this year's summit, whose agenda is set to be dominated by energy security, global health, trade and Iran's nuclear ambitions.

Blair says a 'G13' would be more effective at negotiating a successor to the Kyoto Protocol on climate change than the considerably larger UN Framework Convention on Climate Change, which counts 189 parties.

"There is no way we can deal with climate change unless we get an agreement that binds in the US, China and India," Blair told The Guardian newspaper. "We have got to get an agreement with a binding framework."

"There is no point in thinking (the United States) is going to enter a binding commitment to change the structure of the US economy without China and India being part of the deal.”

But according to Saleemul Huq and Camilla Toulmin of the International Institute for Environment and Development, the 13 nations must realise that their efforts to tackle climate change have "been woefully small in relation to the scale of the problem".

"This global issue cannot be left to the leaders of a handful of countries to decide behind closed doors, however powerful or populous they may be," they said in an article published this week by OpenDemocracy. "It must involve citizens and civil-society groups from countries around the world."

Saleemul Huq chairs SciDev.Net's advisory panel on climate change.