The only way to meet international poverty targets is by a massive switch to renewable energy, such as solar power, a UK think-tank says.
The New Economics Foundation (Nef) says the cost of climate change and oil scarcity will otherwise scupper attempts to help the world's poorest.
It wants an end to subsidies for fossil fuel projects, and nuclear power.
Over the next decade, it says, two billion of the poorest people should be given access to clean energy.
In a report, The Price Of Power, Nef says: "Renewable energy is the great, barely-tapped solution to the two great challenges of the coming century - poverty and global warming."
It says the costs of natural disasters mostly linked to global warming reached $60bn last year, with the warming triggered by the burning of fossil fuels - coal, oil and gas.
The report says a single year's worth of World Bank spending on fossil fuel projects could be spent instead on small-scale solar installations in sub-Saharan Africa, providing electricity for 10 million people.
Reshaping our energy supply holds the secret to ending poverty and preventing global warming. Small-scale renewables remain the best answer for communities and the environment
Andrew Simms, Nef
And a year's worth of global fossil fuel subsidies could "comfortably" pay off sub-Saharan Africa's entire international debt burden, leaving billions of dollars to spare.
The report says these subsidies amount conservatively to about $235bn a year. It argues that they both distort the global economy and hold back the development of renewables.
This, Nef says, is worsened by the failure to factor into the price of fossil fuels the direct costs of damage caused by the emission of carbon dioxide, one of the main greenhouse gases.
The UK government estimates the cost at £50 to £200 pounds per tonne.
Andrew Simms of Nef said: "Around the world control of fossil fuels is linked to corruption and violence.
"Burning them causes climate change which in turn puts an impossible obstacle in the way of ending poverty.
"Reshaping our energy supply holds the secret to ending poverty and preventing global warming. Small-scale renewables remain the best answer for communities and the environment."
The report says governments should adopt several key targets for spreading the availability of renewable energy.
They include: Implementing the target of the G8 group of industrialised countries to provide at least one billion people with renewable energy by 2010, and increasing the target of access to clean energy by the poorest people to two billion over the next decade
Reforming international financial institutions to allow a "dramatic" increase in funding for renewable energy sources in developing countries
Phasing out World Bank group subsidies to fossil fuel projects by 2008, and all government subsidies for fossil fuels and nuclear energy.
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