Up to a quarter of global food production could be lost by 2050 as a result of climate change, land degradation and loss, water scarcity and species infestation, warns the United Nations.
The scenario will strike just as 2 billion more people are added to the world's population, according to the UN Environment Programme, which says cereal yields have stagnated worldwide and fish catches are declining.
In its report, it said a 100-year trend of falling food costs could be at an end and that last year's sharp price rises had driven 110 million people into poverty.
Prices may have eased from those peaks in many areas, but experts say volatility - combined with the impact of the global economic downturn - has meant little respite for the poor.
"We need to deal with not only the way the world produces food but the way it is distributed, sold and consumed, and we need a revolution that boosts yields by working with rather than against nature," said UNEP executive director Achim Steiner.
More than half of the food produced worldwide today was either lost, wasted or thrown away due to inefficiencies, he said.
"There is evidence within the report that the world could feed the entire projected population growth alone by becoming more efficient while also ensuring the survival of wild animals, birds and fish on this planet," Mr Steiner said.
The report said world food prices were estimated to rise by between 30% and 50% in coming decades - while the global population is tipped to climb from 7 billion to more than 9 billion.
It suggested price regulations for commodities should be introduced and larger cereal stocks set aside to guard against price volatility. It also called for "safety nets" to be established for those most at risk from hunger.
It also said more than a third of the world's cereals were being used for animal feed, and that this proportion was expected to rise to a half by 2050. It proposed using recycled food waste as an environment-friendly alternative.
