Is urban agriculture a sustainable food production prospect?

Lead University: The University of Manchester

Dr Laurence Stamford, Marcella Septyameidiana

Summary

To feed the world’s population by 2050, farmers will have to increase total food production by 70% (FAO, 2009). Simultaneously, The World Bank estimates that the global population living in cities will increase by 50% to 6 billion by 2045 (World Bank, 2015). Consequently, there is an opportunity to exploit urban agriculture methods, such as rooftop greenhouses, which could reduce food transport distances and share energy and water resources synergistically with the buildings on which they sit.

The potential environmental impacts of these systems are not well established at present. Therefore this project aims to analyse the life cycle environmental impacts and energy requirements of vegetable production, focusing on tomato and lettuce, in rooftop greenhouses. The specific objectives of the project are:

  • To conduct a life cycle assessment of vegetable production via rooftop greenhouse methods and the equivalent conventional methods;
  • To analyse hotspots in the environmental impacts of the rooftop methods from cradle-to-grave;
  • To compare energy use and other environmental impacts of conventional methods to those of rooftop greenhouse methods; and
  • To suggest potential improvements for future rooftop greenhouse developers in order to minimise environmental impacts and energy use.

Highlights

Preliminary findings include the following:

  • Environmental impacts of rooftop greenhouses (RTGs) are highly dependent on yield.
  • Carbon footprint is broadly comparable to conventional greenhouses.
  • Polycarbonate and perlite are the major contributors to all impacts assessed.
  • If heating is needed, RTGs should have lower impacts due to waste heat utilisation.
  • The benefits of reduced food transportation are currently being investigated.

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