London, April 14: According to the most optimistic predictions about global warming the world’s temperature is set to rise by 3 degrees Celsius, putting up to 400 million people at risk of hunger, the British government’s chief scientist has warned.

Prof Sir David King said that even by the most optimistic assessments carbon dioxide levels were set to rise to double what they were at the time of the industrial revolution.

“If you ask me where do we feel the temperature is likely to end up if move to a level of carbon dioxide of 500 parts per million ? which is roughly twice the pre-industrial level and the level at which we would be optimistically hoping we could settle ? the temperature rise could well be in excess of 3 degrees Celsius and yet we are saying 500 parts per million in the atmosphere is probably the best we can achieve through global agreement,” he said.

If no steps were taken to manage the change, few eco-systems would be able to adapt and up to 400 million people could go hungry as between 20 million to 400 million tonnes of cereal production was lost.

Prof. King warned that even if international agreement could be reached on limiting emissions, climate change was inevitable.

He said that situation would be even worse if temperature rises went beyond 3 degrees Celsius. “If we go beyond 500 parts per million we reach levels of temperature increase and sea level rise in terms of the coming century,” he said.