These cattle are on a diet. A small herd of 20 grazers in this field at Brook Hall Estate in Derry-Londonderry, Northern Ireland, don’t just have grass to eat – willow leaves are on the menu, too. And this silvery green foliage could help shrink their carbon footprint.
“Our willow leaves are full of condensed tannins, which will interrupt the formation of methane,” says John Gilliland, farmer, entrepreneur, honorary university professor and former president of the Ulster Farmers’ Union.
Methane, comprising carbon and hydrogen, is a greenhouse gas 26 times more potent than carbon dioxide – so it’s a significant driver of climate change. Research suggests that increasing the condensed tannins in a cow’s diet could reduce the amount of methane emitted when the animal belches or breaks wind.
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Such trials aim to measure the impact of this dietary change. It’s just one of various approaches Gilliland is testing in an effort to radically redefine the role of farms and farmers in the fight against climate change.
Livestock farming around the world is facing scrutiny because of its greenhouse gas emissions. Globally, the sector contributes somewhere between 11.1% and 19.6% of total emissions. Meat production is roughly twice as bad as the production of plant-based food, according to some analyses. And beef is the worst of all. Study after study has suggested that, in order to curtail the devastating effects of climate change, we ought to shift to a diet containing less meat – or even go vegetarian or vegan.
Can beef be environmentally-friendly?
Emissions from beef production are only half of the story, though. Gilliland argues that many cattle farms can be major carbon sinks, absorbing large quantities of CO2 from the atmosphere, potentially even enabling these farms to reach net-zero status – in other words, harmful emissions would be offset by atmospheric carbon absorbed, for example, through sequestration in soil or vegetation.
The idea of reduced-carbon or even climate-friendly beef is enticing to many meat eaters. Earlier this year, Argentina – the world’s fifth-largest beef producer – announced a new certification scheme for ‘carbon-neutral’ beef.
In the UK, meanwhile, agricultural researchers say that some livestock operations are less damaging to the environment than you might expect. So can we really go that bit further, as Gilliland suggests, and enjoy environmentally guilt-free beef?
How can tech help make cattle farming more ecofriendly
Willow trees have been grown on the gently sloping fields of Brook Hall Estate for more than 30 years. Latterly, they were used primarily to provide wood chips for biomass boilers. But when Northern Ireland’s Renewable Heat Incentive scheme was hit by scandal and collapsed in 2017, the market for Gilliland’s willow chips evaporated. He was forced to sell three-quarters of his land to pay debts. “It has absolutely crucified us,” he says. “This farm doesn’t make any money at the moment.”
In the years since, Gilliland has shifted his focus, working as an advisor on the environmental impacts of livestock farming. He leads the ARCZero project – a network of seven farms in Northern Ireland, including Brook Hall Estate, that have agreed to undergo detailed analysis of their carbon stocks.
To this end, Gilliland has championed the use of technology. Lidar – a remote laser-based sensing method – has helped to map and measure how well the farms are storing carbon, by quantifying the volume of above-ground vegetation.
It works like this: a small aircraft carrying a Lidar instrument flies repeatedly over a farm, taking 40 scans per square metre. Gilliland shows me the results on his laptop computer: a colourful image of Brook Hall Estate on which blobs of different colours indicate the varying heights of trees, allowing him to estimate the total amount of carbon stored in them.
How can soil be improved to store more carbon?
The really important bit, stresses Gilliland, is the soil. To assess the amount of carbon stored below ground on the seven ARCZero farms, a specialist firm, Agricarbon, analysed the soil on each site, testing at least 2.5 locations per hectare to a depth of one metre. In every case, the soil contained the vast majority of total carbon detected on these landscapes – 80–98%, depending on the farm.
The amount of carbon locked up in farmland soil can vary significantly. Gilliland and his collaborators hope to prove that they can store more carbon on these farms over time by changing management of the land – for example, by raising soil pH or by bringing cattle into a previously ungrazed field to deposit their dung, potentially improving organic content and microbial activity in the soil.
Though each of these methods is inspired by published research, it is not yet possible to measure the exact contribution of any specific tactic. But Gilliland points to a body of evidence from respected bodies such as Rothamsted Research, and adds that the ARCZero farms can now monitor changes in their carbon stocks over time. “At least now we’ve got a framework and a rigour,” says Gilliland, who proposes follow-up surveys every five years.
The ARCZero approach is not solely an attempt to balance emissions against sequestration. Gilliland also advocates increasing plant diversity – for example, by planting legumes. These help fix nitrogen in the soil, encouraging grasses to flourish. This in turn allows farmers to reduce their use of nitrogen-based artificial fertilisers – thereby cutting the emission of nitrous oxide, a greenhouse gas 270 times more potent than CO2.
Gilliland also encourages nurturing herbs such as chicory within pasture to provide a varied diet for cattle and to increase biodiversity. Chicory’s long taproots also help the land soak up heavy rainfall more quickly. That could reduce runoff, which can spread phosphates and other pollutants into farm-adjacent waterways. Assessing the effects of such innovations through Lidar and soil organic carbon measurements at scale could transform views of the impacts of agriculture in the UK, he suggests. It’s worth noting that opinions currently differ about the extent to which agricultural management practices can influence carbon sequestration. Even so, it is worth trying, Gilliland says.
What are the true environmental costs of cattle and farming?
When weighing up the environmental impact of meat production, one key metric is the quantity of greenhouse gases – or carbon dioxide equivalents (CO2e) – emitted per kilogram of meat taken off the farm.
Estimates of emissions from beef production worldwide, including methane, typically use figures stating that, on average, beef has a carbon footprint of 100kg CO2e per 1kg of meat produced. That’s more than 30 times the size of the footprint of tofu, and more than 100 times that of most vegetables.
Gilliland insists that these figures – which refer to gross emissions and don’t account for carbon sequestration on farms – are misleading. Besides, global averages are unlikely to reflect the reality of meat production at the farm just along the road from where you live.
Gilliland and the other ARCZero participants have used a carbon accounting tool called Agrecalc to estimate gross emissions associated with farm produce. Using that method, the beef from one farm in County Fermanagh had a footprint of 25.6kg CO2e per kg in 2023 – a figure that’s fallen since 2021 thanks to changes in farm management practices.
Even without taking sequestration into account, some farms perform much better than the global average. Another study, the UK-wide PRISM 2030 project – which does not yet factor in carbon sequestration – found that, though the majority of farms emit 30kg CO2e per kg of beef, a handful produce less than 15kg CO2e per kg.
Gilliland says we will get an even better idea of farms’ actual impact once they begin measuring their own carbon stocks more accurately.
Should everyone go vegan?
Though emissions from UK beef farms seem to be much lower than the global average, some argue that more detailed data – including analysis of carbon sequestration on farms – is unlikely to change our broader understanding of how meat-based food production contributes to climate change.
A study published last year, based on global averages, suggested that reducing meat consumption, or cutting meat from our diet entirely, could significantly reduce greenhouse-gas emissions and impacts on biodiversity and water use.
However, lead author Peter Scarborough, professor of population health at the University of Oxford, notes that the study was not designed to specifically assess the impact of meat sold in the UK. The idea of everyone going vegan is “completely unrealistic”, Scarborough adds. Even when considering the impact of reduced-carbon beef, though, the takeaway message of his paper is: the lower the amount of meat you eat, the smaller the environmental impacts.
Another expert exploring the impacts of farming is Margaret Gill, emeritus professor in biological sciences at the University of Aberdeen, who has spent decades studying livestock production. She says we don’t have any time to lose: the world must slash emissions rapidly. The deadline for hitting many targets designed to limit the catastrophic effects of climate change is 2030 – only six years away. “We’ve got to really make a significant impact on greenhouse gases,” she says.
Gill’s stance is that accurate carbon accounting on farms is challenging. That said, she praises the work of Gilliland, and calls ARCZero a “great project”. And, though she observes that it may be difficult to determine with precision emissions figures for beef that account for all inputs and outputs – and also that we should take such numbers with a pinch of salt – she argues they prompt a discussion about how livestock farming could improve to reduce overall emissions.
Can farming ever be net zero?
Gilliland, for his part, remains optimistic, insisting that livestock producers “…can get their system quite close to net zero, or even beyond net zero”.
He describes diets that are 100% plant-based or 100% meat-based as “extremism”. “My view is that people do need a balanced diet,” he adds. However, he supports the recommendation issued by Food Standards Scotland that people who eat large quantities of red and processed meat should cut their consumption back to an average of 70g or less per day.
Gilliland makes another point regarding the role of farmers more broadly. They are fed up, he asserts, of being made to feel like pariahs in discussions about climate change, when they could instead be part of the journey towards reduced emissions. “We need people to get better,” he says. “To get behavioural change, we need enough sophistication in our measurements,” adding that farmers are more motivated when they get to see their own results.
Everyone should be pushing for more carbon-efficient systems, agrees Gill, because the climate-change clock is ticking ever louder: “Unless some action is taken, it’s rather like going over a cliff edge.”
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