Turning down the heat on farming

Potato planting

12 April 2013 by Tom Marshall

Whether you're raising potatoes in Wisconsin, coffee in Kenya or cows in Cornwall, growing the world's food and drink has environmental costs before you even think about transporting it, processing it, keeping it cool and eventually cooking and serving it. Tom Marshall reports on a new web tool that's helping farmers understand their emissions.

Farms produce a lot of greenhouse gases (GHGs) - in 2011, the Carbon Disclosure Project estimated the agriculture sector was responsible for some 14 per cent of human global emissions. Like most people, farmers burn fossil fuels for lighting, heat and transport. But there's also methane from manure and composting, and nitrous oxide from nitrogen-based fertilisers.

Many farmers want to do better. And the big companies that buy their produce are often even keener; they now routinely plan for tightening regulations on greenhouse-gas emissions, and want to get ahead of the game. So they're leaning on farmers to cut their emissions.

But for farmers, acting on a desire to improve isn't always easy. There are hundreds of changes they could make around the farms, with varying costs, and it's not obvious which would bring most improvement for least money. What if they were to adopt a new mixture of crops? Change how they plough? Or should they invest in precision-fertilisation technology? (This lets them apply nutrients exactly where they're needed and nowhere else - it's costly, but can boost yields as well as saving chemical fertiliser and cutting emissions.)

For farmers without scientific training, evaluating the options can be near-impossible - scientific models of carbon emissions take specialised knowledge to use, and need to start with carefully-tailored parameters if they're to represent a particular situation accurately.

Strawberry picking

The Cool Farm Tool (CFT) aims to help. Launched last summer, it's already being adopted enthusiastically by farmers all over the world and is helping bring them together with food processors, scientists and environmentalists. It gives them a simple but accurate way to estimate a farm's GHG emissions. Farmers enter some simple information about their land, its soil type and what they do on it; they are then presented with a summary of emissions and potential steps to cut them.

The CFT doesn't just calculate total emissions; it breaks them down so the farmer can see where their emissions are greatest and where they can make the biggest difference most quickly. If it turns out that the main problem is carbon loss from the soil, there's not much point spending a fortune on fuel-efficient tractors. And while it's based on the best available information, it's designed to be used by non-specialists. It's early days yet, but so far the response has exceeded its creators' expectations - it's now being used by groups from Indian cotton growers to the Americans who produce the tomatoes that end up in Heinz soup. And their feedback is enthusiastic.

"The industry saw the need for a tool that was driven by real data from farms and that packages good science in a way farmers can access," says Dr Jonathan Hillier of the University of Aberdeen, the CFT's creator and a NERC Knowledge Exchange fellow. 'Before this, there wasn't much that was helpful for them; what's best for each farmer depends on what they are producing, where they are and how the costs and benefits balance out. It's all about trying to find the low-hanging fruit, and this will be different in each situation."

The project got started when the sustainability team at Unilever, the Anglo-Dutch consumer-goods giant, approached Hillier asking for something simple that could help its farmers understand their emissions and what they could do about them.

Since then, other big players in the food and drink industries have joined the project, including PepsiCo, Marks & Spencer, Tesco and Heineken. They have a common interest in emissions-cutting, which means working with the farmers who supply them - researchers think up to 80 per cent of the average fresh foodstuff's total emissions happen before it leaves the farm.

Everyone gains from using the CFT. Farmers and food companies get to cut emissions as efficiently and painlessly as possible. Scientists get to spread their knowledge about the most effective ways to do this, with big companies carrying the word to hundreds or thousands of small farmers and working with them to put theory into practice - something the researchers would struggle to do themselves. 'The great thing of being a big company with a short supply chain is that you can work directly with farmers to do this kind of thing," Hillier says.

Dairy cows

One such company is PepsiCo. It owns Walkers Crisps and has set a goal of halving the carbon emissions of its agricultural raw materials over five years. This means engaging directly with its contract growers – the farmers who produce potatoes for it, for example – to develop carbon-reduction targets. "When I first heard about that, I thought it was incredibly ambitious," Hillier admits. "But we've now shown this kind of collaboration works; it cuts emissions in a cost-effective way. So I now think the target is achievable."

Hillier's team is now using NERC funding to put together an extended version of the CFT that will go beyond GHG emissions to show other aspects of farms' performance, ranging from water quality to harder-to-quantify measures like biodiversity. The idea is to give farmers a better sense of the big picture and how different goals can conflict - so that in trying to cut GHG emissions they don't do something to harms rare birds living on their land, for instance. There's also a new web version of the tool on the way. At the moment it works in Excel; it does the job but is hardly a thing of beauty.

Hillier argues that this sort of collaboration between scientists and industry is vital if we're to cut emissions as much as we need to. Hearteningly, the industry now needs little persuading to get involved. "Many farmers are genuinely concerned about the environment, but without some external pressure the farming industry as a whole isn't likely to take much action," he says. "That pressure is now coming from big food companies like the ones we work with. For them, it's just long-term strategy; they see more policy, regulations and consumer pressure on the way, and they want to get in early and be seen as pioneers. We're not talking about some fluffy green mindset - it's in their interest to be prepared."

(This second paragraph of this story was edited on 16 April 2013 to clarify that agriculture accounts for 14 per cent of human greenhouse-gas emissions, not of all greenhouse-gas emissions including natural ones.)