The assumption that climate change will hit the poorest people hardest has been shaken by new research from Stanford University suggesting that the worst-case global warming scenario predicted by the United Nations over the next 20 years could actually lift millions of people out of poverty.

The Copenhagen climate conference agreed that the developed countries would establish a fund to help poorer countries to adapt to the worst effects of climate change, such as flooding and drought. The new research by David Lobell of Stanford University’s Program on Food Security and the Environment gives an idea of where some of that money ought to go.

Rising temperatures have a generally detrimental effect on plant growth. Lobell and his colleagues used predicted global temperature rises from the Intergovernmental Panel on Climate Change and extrapolated from them the likely increase or decrease in crop yields. That data was fed into a computer model developed by Purdue University agricultural economist Thomas Hertel which can predict the impact of yields on food prices and poverty by 2030 in 15 Asian, African and Latin American developing nations.

The results make for interesting reading. Under the IPCC’s ‘most likely’ scenario, that of a 1C temperature rise by 2030, there was no overall change in poverty levels.

But there are two less likely scenarios, which have a five per cent probability of coming to pass: a 0.5C rise and a 1.5C rise. These seemingly tiny differences in temperature will have very different effects on crop yields and poverty.

A 1.5C temperature rise would reduce crop yields and increase the price of wheat, rice and maize by 10-60 per cent. Although it would increase poverty overall in the 15 countries by three per cent, farmers who owned their own land would enjoy a bonanza: as food prices soar, they could sell their crops for a premium.