Climate change will push food prices even higher and trigger “hotspots of hunger” among the world’s poorest people, UN experts warned yesterday.

“We’re facing the spectre of reduced yields in the key crops that feed humanity,” said Intergovernmental Panel on Climate Change (IPCC) chairman Rajendra Pachauri.

A hotter planet with higher levels of carbon dioxide will produce less food than a world without global warming, the IPCC said.

The panel’s previous report in 2007 said it was too early to tell about climate change’s effect on agriculture.

But since then scientists have overwhelmingly shown the negative effects, said Chris Field of the Carnegie Institution of Science.

In some places global warming has undercut improvements in farming techniques, reducing the increase in crop yield.

And such techniques are only effective in irrigated areas — not countries such as India, where 800 million rely on rainfall to water crops, warned Mr Pachauri.

“Increasing magnitudes of warming increase the likelihood of severe, pervasive and irreversible impacts.

“Nobody on this planet is going to be untouched by the impacts of climate change.”

Although changes in rainfall hurt, mostly the problem will be too much heat, said David Lobell of Stanford University. “No place is immune.”

Food prices are likely to rise by up to 84 per cent by 2050 just because of climate change, the IPCC said.

“In a world where a billion people are already going hungry, this makes it harder for more people to feed their families,” warned Tim Gore of Oxfam International.

While some crops may do slightly better, staples such as wheat and corn will be hurt.

And warmer and more acidic oceans are causing fish to move around, making them harder to catch and hurting people who rely on seafood, Mr Pachauri added.