Warning over global food supply

Tackling climate change is central to preventing food insecurity - which could otherwise prove the "weak link" which destroys civilisation, an environmental expert has warned.

Lester Brown, who founded the Earth Policy Institute and the WorldWatch Institute, said the "bottom line" of climate talks in Copenhagen in December was about delivering food security for the global population.

He warned grain supplies were already under pressure from a growing world population, a growing demand for more meat products and a huge shift towards biofuels in the US.

Mr Brown said the impacts of water shortages and sea level rises on production in Asia could see China competing with the US for its grain harvest - pushing up prices at the till for consumers.

He said he was concerned that negotiators attempting to draw up a deal in Copenhagen on tackling climate change had "got lost in the intricacies" of the agreement and were not focusing on the central problems, such as food security.

"The idea we can invest in energy resources that last not only the next generation but all generations to come is really pretty exciting," he said.

But he warned that the market alone would not deliver the low-carbon revolution that is needed to combat climate change, unless taxes were altered to reduce income tax and increase the price of carbon to reflect the true cost of pollution.

A deal in Copenhagen was a necessary part of moving the world to a low carbon economy but, he warned, "we can't depend on Copenhagen to save civilisation".

Mr Brown is launching his latest book Plan B 4.0: Mobilizing to Save Civilization at Compassion in World Farming's Peter Roberts Memorial Lecture in London on Thursday night.

The book sets out a revolution in energy efficiency, increased tree cover and green energy which would help the world cut its emissions by 80% by 2020 - a figure which he acknowledged was not "politically popular" but would have a decent chance of preventing the melting of glaciers and ice sheets.