The 2013 Urban Agriculture Summit, held this week in Linköping, Sweden looked at the challenges of growing food for an increasingly urbanised global population whilst reducing impact on the environment.

By 2050 the Earth's population will have risen to an estimated 9 billion. 80 percent of these people will live in cities. The ways in which cities are expanding is also providing new challenges for food distribution, meaning new sustainable solutions need to be found. However, this week's summit in Sweden was only the second such meeting; the first being held in Washington, DC in 2011.

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Already, over the half the world's population lives in a city. There is widespread concern that, as the population expands, so too will the area used to grow food; there is a growing threat that production increases will convert more 'natural ecosystems' such as forests and savannas, which often support low-impact small-holder agriculture run by local communities, to large-scale commercial farming.

Delegates at the conference form part of a movement which suggests food production should shift to the areas where most people live, to avoid the worst impacts of production and distribution and allow regeneration of more natural parts of the world.

According to Danielle Nierenberg of US policy organisation Worldwatch, who spoke at the symposium on Tuesday, at least 800 million people worldwide already participate in some form of urban food production. However, she said the practice must be encouraged on a policy level, adding "Finding better ways for farmers and food entrepreneurs to grow food, raise livestock, and process and manufacture food in cities is more important than ever before."

Nierenberg gave examples of diverse urban growing projects in North America, from community-based initiatives in New York, San Francisco and Milwaukee, to more entrepreneurial local food networks developing in Chicago, where the Every Last Morsel project is digitally mapping small-scale food production to connect urban growers. She said these models should be supported and rolled out.

The UN Food and Agriculture Organisaion suggests the urban agriculture movement is growing worldwide; focusing its work on areas where urbanisation is increasing rapidly, FAO launched the Growing Greener Cities in Africa initiative, to ensure rapidly expanding cities have a good supply of fresh local food, produced in a network of market gardens.

Agricultural research organisation CGIAR, has also launched an initiative which aims to promote the role of urban agriculture in policy decisions, particularly in tackling poverty.

High tech approach: World's first industrial-scale vertical farm

However, the Summit's organisers are championing a high-tech approach to urban growing. In the run up to the summit, plans were unveiled for the ‘Plantagon’ urban agriculture project in Linköping; a vertical greenhouse in which more food can be produced at lower cost to growers and consumers alike.

The project is a joint venture between the Swedish government, research institutes and industry. Hans Hassle, CEO of Plantagon International said the project is a means of "Trying to find technical solutions to feeding the future huge mega-cities of the world."

Hassle said the vertical farming approach maximises production, whilst minimising stress on land and water, and reducing the energy used to grow food, by growing food in multi-story greenhouses to make the most of space in cities. The project in Linköping is expected to begin producing food by the end of 2013, though construction has not yet begun.

Plantagon CEO Hassle added the 'vertical farm' will have a production capacity of 300-500 tonnes of vegetables a year, with a land footprint of just 400 m2. The system will use a combination of hydroponics and volcanic stone, to give a similar taste and nutritional balance to growing in soil.

By marketing the produce direct to consumers, the team behind Plantagon hope to provide benefits for themselves and their customers.

Having identified problems facing large-scale urban growers, including poorer air quality in cities and distribution issues relating to centralised production in a large city, Hassle said the farm's location had to be carefully taken into account and added, "In a dirty city environment you need to grow things in a closed system, or at least a semi-closed system… to protect it from having to use pesticides and other things."

He said the building will be crafted to make the most of space; a glass outer and a helical (spiral) interior would allow for optimal sunlight to enter the building. The revolutionary design will also move crops around within the building, which Hassle said increases efficiency.