To feed the world we need agricultural systems that are not only productive, but also sustainable and equitable

Global food crisis: Losetta Mathew and Jacob Chabane with their goats in Uganda. The world needs sustainable and equitable answers to tackle the problem. Photograph: Graeme Robertson for the Guardian
People tell me I’m an optimist. But right now this optimist is scared. We are facing some formidable challenges: 1 billion people chronically hungry, recurring food price spikes, extreme climate change impacts, and feeding more than 9 billion people by 2050 with no additional arable land. As John Beddington, the UK’s chief scientific adviser, has said, we risk “a perfect storm” of crises that will cause major social and political upheaval.
In 1997, I published a book called The Doubly Green Revolution: Food for All in the 21st Century. In it I argue that to feed the world we need agricultural systems that are not only productive, but also sustainable and equitable. I am convinced that this quest for a “doubly green” approach is more important than ever today. So how might we achieve a doubly green world?
I believe we should draw on all technical tools available to us for food production: conventional technologies such as fertilisers and pesticides, but used with precision; intermediate technologies such as improved treadle pumps; traditional technologies such as rainwater harvesting techniques; and new platforms for innovation based on scientific advances such as genetically modified crops for drought, pest and disease resilience.