A UK government-commissioned study into food security has called for urgent action to avert global hunger.
The Foresight Report on Food and Farming Futures says the current system is unsustainable and will fail to end hunger unless radically redesigned.
It is the first study across a range of disciplines deemed to have put such fears on a firm analytical footing.
The report is the culmination of a two-year study, involving 400 experts from 35 countries.
According to the government's chief scientific adviser, Professor Sir John Beddington, the study provides compelling evidence for governments to act now.
The report emphasises changes to farming, to ensure that increasing yields does not come at the expense of sustainability and to provide incentives to the agricultural sector that address malnutrition.
It also recommends that the most resource-intensive types of food are curbed and that waste is minimised in food production.
"We know in the next 20 years the world population will increase to something like 8.3 billion people," he told BBC News.
"We know that urbanisation is going to be a driver and that something of the order of 65-70% of the world's population will be living in cities at that time.
"We know that the world is getting more prosperous and that the demand for basic commodities - food, water and energy - will be rising as that prosperity increases, increasing at the same time as the population."
He warned: "We have 20 years to arguably deliver something of the order of 40% more food; 30% more available fresh water and of the order of 50% more energy.
"We can't wait 20 years or 10 years indeed - this is really urgent."
Professor Beddington commissioned the study and was among the first to warn of "a perfect storm" of a growing population, climate change and diminishing resources for food production.
The Foresight report says that the food production system will need to be radically changed, not just to produce more food but to produce it sustainably.
"There is an urgency in taking what may be very difficult policy decisions," the authors say.
"(But) 925 million people suffer hunger and perhaps a further billion lack micronutrients. The task is difficult because the food system is working for the majority of people but those at risk of hunger have least influence on decision-making."
Professor Beddington also said he viewed the billion people who overeat and are therefore obese as another symptom of the failure of the food production system to deliver good health and well-being to the world's growing population.
The report says that "piecemeal" changes are not an option: "Nothing less is required than a redesign of the whole food system to bring sustainability to the fore."
The authors are calling for food and agriculture to move up the political agenda and be co-ordinated with efforts to tackle the impact of climate change, water and energy supplies and the loss of farm land.
They also warn that there is no "silver bullet" that will solve the problem but concerted action is needed on many fronts.
Professor Beddington said: "We've got to actually face up to the fact that this is a complicated problem which involves vastly different levels of society and we need to be persuading policy makers not to think about food in isolation, not to think about climate change in isolation, not to think about water in isolation, not to think about energy in isolation. All of them are intimately related."
The report adds that new research can play an important role. It also says that the use of any particular technology, such as genetic modification, cloning and nanotechnology should not be ruled out. But it acknowledges that there is resistance to the application of controversial technologies.
"Achieving a strong evidence base (of the safety or otherwise) in controversial areas is not enough. Genuine public debate needs to play a crucial role," the report says.
However, by assessing 40 success stories from Africa the report authors say the spread of existing best-practice could treble food production.
"Ending hunger is one of the greatest challenges to be considered by this project," the report observes.
It calls for protection of the poorest from sharp price increases through government intervention and greater liberalisation of the trade in food in order to offset market volatility.
They also note that China has invested heavily in agriculture and is consequently one of the few countries to have met the Millenium Development Goal (MDG) of halving hunger.
The report also calls for new measures to hold governments and food producers to account. This would involve developing objective measures on how well they are doing to reduce hunger, combat climate change and environmental degradation and boosting food production.