Griffith Review

By Andrea Koch

Working in sustainable food and agriculture means confronting some of the biggest wicked problems of our time: climate change, declining fresh water, a projected global population of nine billion people, and the planet's ability to supply their needs for food, fibre and energy. Solutions to any one raises problems in solving the others at the nexus of water, energy and food production.

For some time I have had a hunch that remedies lie in things that grow, that come from the soil: things of an agrarian nature. Can we harness the prolific and continuous energy from the sun, through nature's mechanism of photosynthesis, to meet our needs for food, fibre and energy? Can the planet support a healthy population half as big again? Biomass for green energy production, algae for oil, closed-loop agricultural systems for the production of nutritious food and fibre – these are the kind of things-that-grow scenarios with which I am preoccupied.

In early 2011 I participated in an extraordinary meeting of twenty of the world's leading soil and plant scientists. The scientists came to Sydney from North America, the United Kingdom, Europe and Australasia for the inaugural Soil Carbon Summit to deliberate the science of soil carbon sequestration and its potential in improving soil function, abating climate change, and girding water, food and energy security. What made this meeting unique was the calibre of the people in the room: six centuries of combined experience, the very top minds in soil science in the world. This esteemed group very quickly established consensus on the state of the science of soil, and concluded that soil carbon sequestration has the potential to secure the future of the world's soils.

This is the story of what emerged: the conclusions reached and the message of hope that it produced. We can solve these big wicked problems. This is the story of soil.

Most of us now know that too much carbon in the atmosphere is a bad thing, but few realise that the reverse is true in the case of soil: carbon in soil is a good thing. Carbon in soil is essential for life. The carbon in soil holds it together. Without carbon, soil is dirt that grows nothing. Carbon in soil powers the nutrient cycle, nutrients in dead organic matter turning back into a form that promotes the growth of food and fibre. The carbohydrates we eat in various forms every day depend on how the soil in which they are grown interacts with carbon and the plant. The other terrestrial foods in our diet also rely on soil carbon: without it, it is impossible to grow protein and fats – meat, plants or dairy.

Carbon in soil is a great indicator of the fertility and resilience of the soil. Soil that is high in carbon retains more water, is resistant to erosion and produces more food. Carbon in soil is unambiguously a good thing.

This is an extract from the full essay published in Griffith Review (Edition 32).