American scientists are calling for the rapid development of so-called “vertical farms” – giant multi-storey greenhouses in urban centres – if mankind is to stave off starvation in the next 50 years.

A report by Professor Dickson Despommier from Columbia University, New York explains that, even applying the most conservative estimates, the human population will increase by 3bn people by 2050. Feeding them using conventional agricultural techniques will require another 10bn ha – an area 20% more than the size of Brazil.

Instead, Prof Despommier is recommending the scaling up of indoor farming techniques in urban centres. “If successfully implemented, they offer the promise of urban renewal, sustainable production of safe and varied food and the eventual repair of the ecosystems that have been sacrificed for horizontal farming,” he says.

Among the advantages, he points out that vertical farms could offer year-round production of organic food, using recycled water with no weather-related crop failures and reduced use of fossil fuels.

He estimates that it takes approximately 300 square feet of intensively farmed indoor space to produce enough food for one person for one year. “On these calculations, one vertical farm with an architectural foot print of one square city block and rising to 30 stories could provide enough nutrition to comfortably accommodate the needs of 10,000 people employing technologies currently available.”

Increasing yields further will require additional research in many areas, including hydrobiology, waste management, urban planning and plant and animal genetics. But, while he admits that the vertical farm is “a theorectical construct”, Prof Despommier insists that its time has arrived.

“The time is at hand for us to learn how to safely grow our food inside environmentally controlled multi-storey buildings,” he says. “If we do not, then in just another 50 years, the next 3bn people will surely go hungry.”