What food really means

Water pump

Water pump

19 April 2013 by Tim Benton

Food is not just something we eat. Its fluctuating price and availability mean it will be one of the main ways many of us will interact with the environmental issues of our time: climate change and competition for water, land and energy. Tim Benton explains why.

By the middle of the century, global demand for food is projected to grow by about 60 per cent, as population rises, and the burgeoning global middle class develops more sophisticated tastes and devotes more money to satisfying them. But how easy will it be to increase supply? Climate change is already affecting crop yields, through an increase in extreme weather, and this is only likely to get worse. Even if conditions were more favourable, most of the land available for agriculture is already in use; at about five billion hectares, agriculture effectively covers most land not occupied by rainforests and deserts.

Land availability isn't the only constraint. Agriculture already uses about 70 per cent of the world's available fresh water resources: with other demands on water likely to grow too, this means we have to find a way to meet the projected increase in demand for food using the same amount of water. Energy is another big issue, affecting the costs of food transport, fuel availability for agricultural processes and the production of synthetic fertilisers.

How do we considerably increase food production, using less land, less water, less fertiliser and in the face of climate change? And, at the same time, how do we reduce its environmental impact?

Nitrogen fertiliser being scattered

Nitrogen fertiliser being scattered across the land by tractor.

Globally, agriculture has probably the greatest environmental impact of any human activity. Some 25 per cent of global greenhouse gas emissions are associated with agriculture and the conversion of land to it; up to a quarter of the soils used for agriculture around the world are degraded, and over 12 million hectares have to be abandoned every year because the soil can no longer support crops. And the loss of global biodiversity, with all the benefits it brings us, is probably incalculable. In our eagerness to turn the world over to agriculture over the last 50 years, we have not paid due regard to the natural resources that are critical both for agriculture and for our survival.

With no more land available to meet increasing demand for agricultural produce, our only option is to produce more food on the land we do have. But if we are going to intensify agriculture in this way, we have to ensure we do it with the minimum environmental impact. We need intensification, but we also need to improve and protect ecosystem services - we need 'sustainable intensification', with equal emphasis on both. But intensification here is not a clarion call for greater industrialisation of farming: sustainably producing more food can come about by increasing our knowledge, labour or technological inputs. An allotment gardener or smallholder can produce far greater yields per unit area than large-scale agriculture, by applying their knowledge of the land and more labour-intensive land management (constant weeding, dynamic pest control).

Intense, but sustainable

One important change that is already happening is in the scale of our thinking about ecology and landscape management. An agricultural landscape is not just a collection of individual farms: the pollinators a farmer relies on for one field of crops don't come from that field, but from the population of pollinators supported in the wider landscape. So the sustainable intensification challenge is not to think about sustainable agriculture per se, but the sustainable management of whole landscapes that provide many, connected, ecosystem services.

An agricultural landscape produces food but it also provides water, requires biodiversity to underpin soil function, pollination and other useful services, and also has value to society in terms of aesthetics and recreation. Rather than think about fields producing food, and the rest of the land producing everything else, we need to think about managing integrated, multifunctional, landscapes.

Paddy fields

Paddy fields

It's a neat idea but what does it really mean? How, in practice, can we manage the trade-offs between the different things we want from the land: food, water, biodiversity, recreational value? What is the best way to maintain biodiversity and other services in agricultural landscapes, whilst recognising that there is a growing demand for food? How should the non-cropped land, the hedgerows, the field margins, the coppices, the water courses, be laid out and managed to create the best connected network allowing animals and plants space to live and move? How should the best management vary from place to place? And how do we encourage land managers to put all this in place?

As well as these local considerations we must also recognise the wider context of the agricultural market. The market is a mechanism which connects changes in land use across the globe. If less food is being produced in one place (because land has been set aside to regenerate biodiversity, for example) the market signals the need to replace the 'lost' yield - as prices for that commodity rise and farmers elsewhere increase their own production of it to take advantage.

We've seen the potential for this to happen in Europe, with the spread of wildlife-friendly practices like organic farming. These more sustainable practices produce lower yields, and when demand is growing that shortfall has to be made up by increasing food imports. The overall effect is therefore to shift some of the environmental costs of our food elsewhere - or perhaps even to increase it if it contributes to intensification in the more biodiverse tropics. This doesn't mean organic food is a bad thing - it simply shows the huge challenge of understanding how decisions taken in one place can have global consequences, and of working out how to manage the whole system to get the balance as good as it can be.

Climate change makes this need all the more pressing. The impact of extreme weather on global food production is increasingly creating shortfalls in supply, raising food prices and sending short-term signals to further intensify production. So we must also understand the links between climate, weather, production, environment and economics - the entire food system - and how changes to any of those variables affect the whole system. Only by understanding how changing production practices in one place works through the market and impacts land-use in another place, will we really be able develop truly sustainable food systems.

This is a real interdisciplinary challenge, spanning the biological, environmental and social sciences at least. Collaborative research like the Rural Economy and Land Use (RELU) programme and Biodiversity and Ecosystem Service Sustainability (BESS) have made considerable progress in working out how we can better organise our agricultural landscapes. Meeting the global challenge of sustainable intensification of agriculture will call on even broader partnerships, of which the Global Food Security programme is one.

More information
Tim Benton is the champion for the UK's Global Food Security programme. He is also Professor of Population Ecology at the University of Leeds.