Grass-fed beef is bad for the planet and causes climate change

Prince Charles is wrong to support grass-fed beef. The idea that beef from cows raised on bucolic pastures is good for the environment, and that we can therefore eat as much meat as we want, doesn’t add up. New calculations suggest cattle pastures contribute to climate change.

“Sadly, though it would be nice if the pro-grazers were right, they aren’t,” says lead author Tara Garnett of the University of Oxford’s Food Climate Research Network. “The truth is, we cannot eat as much meat as we like and save the planet.”

Many meat eaters have long felt guilty that the beef steaks they love are bringing environmental disaster.

A key problem is that microorganisms in the guts of cattle emit millions of tonnes of methane every year. A typical cow releases 100 kilograms of methane a year and the world has about a billion of them. Since methane is a greenhouse gas, this exacerbates global warming.

Meanwhile, feeding the beasts destroys forests by taking land for pasture or to grow feed – and this deforestation also contributes to greenhouse gas emissions.

But a counter-view has gained currency. First popularised by Zimbabwean ecologist and livestock farmer Allan Savory, and supported by organic farmers like Prince Charles, it argues that grazing cattle on pastures is actually good for the climate.

The idea is that plants on pastures capture carbon from the air, especially when fertilised by manure. Pastures should also reduce our need for food crops grown on land that releases carbon when ploughed.

Doing the sums

Confused by conflicting claims, Garnett and her colleagues calculated the flow of greenhouse gases into and out of pastures. She found that “in some circumstances, you can get carbon capture, but not always and the effect is small. You cannot extrapolate from a nicely run Dorset farm to a global food strategy.”

At best, carbon capture only offsets 20 to 60 per cent of greenhouse gas emissions from grazing, mostly the methane from cattle. “And the carbon capture stops after a few decades,” says Garnett, when the carbon-enriched soils reach equilibrium with the air. “Meanwhile, the cattle continue to belch methane.”

Her findings are published in a report, Grazed and Confused?

The analysis is more comprehensive than past studies, says Tim Benton at the University of Leeds, UK. “It asks, if we are to eat meat, is there a better way to grow it? The answer is: not really.”

Less meat

Supporters of cattle grazing aren’t giving up just yet, though. Some say cattle have simply replaced wild ruminants, which also release methane. But Garnett points out that many cattle, especially in the tropics, graze on former forest land. In places such as the Brazilian Amazon, clearing trees for cattle causes massive greenhouse gas emissions.

At low densities of around one animal per hectare, carbon capture in soils could still exceed methane emissions, says Richard Young of the Sustainable Food Trust in Bristol, UK, which supports cattle grazing. However, he concedes that this isn’t true at higher densities.

Garnett’s conclusion is supported by a study published on 29 September, which found that methane emissions from cattle are 11 per cent larger than older methods would suggest, and thus a bigger contributor to global warming (Carbon Balance and Management, doi.org/cdpz).

“We need to reduce emissions from livestock,” says Benton. “That needs to come from dietary change.”