Climate change is set to push up food prices, increase hunger and reduce the quality of food, campaigners have warned.
With one in eight people in the world going hungry, the effect of rising temperatures and extreme weather events on production means fewer people will be able to afford enough to eat, Oxfam said.
Those at risk of hunger could rise by up to 20 per cent by 2050 compared to a world where the climate was not changing, the aid agency added.
Oxfam estimates that the average price of staple foods could more than double in the next 20 years – compared to 2010 prices – with up to half the increase as a result of climate change.
In a report ahead of a major global assessment of climate-change science due to be published on Friday, Oxfam said yields were already being hit by global warming and some of the poorest parts of the world could see reductions of between 10 and 20 per cent by 2050.
Global yields of maize over the past three decades were 3.8 per cent below what they would have been without climate change and wheat was 5.5 per cent lower. Food production will be negatively affected in most parts of the world by rising temperatures and shifting weather patterns, while extremes such as droughts and floods will damage crops and kill livestock.
Agricultural disasters such as the 2012 US drought in the Midwest, which cut maize crops by a quarter and sent global prices rising by 40 per cent, are likely to become more frequent, the report said.
In the UK, 2012 was the second wettest year on record, causing wheat yields to fall to their lowest levels in 20 years, meaning Britain had to import 2.5 million tonnes of wheat.
In a separate study, Unicef UK warned that two million children already die each year because they could not get enough to eat and a further 165 million suffered from malnutrition, a situation which was going to deteriorate due to climate change.
Tim Gore, head of policy for Oxfam’s Grow campaign, said: “Leaders listening to the latest findings from climate scientists this week must remember that a hot world is a hungry world.
“They must take urgent action to slash emissions and direct more resources to building a sustainable food system.”
Children fear for the future
British children are worried about the impacts of climate change, according to research.
Children will be dramatically affected by the changing climate and will “carry the burden of our delays and inaction” on tackling the problem, Unicef UK warned.
The warning came as a poll found that three-quarters of children aged 11 to 16 were worried about how climate change will affect the future of the planet
The survey of 1,001 UK children, was part of a report by Unicef UK into the impacts of climate change