Vegetarians and vegans often point out that cows’ methane-filled burps are bad for the planet. But some supporters of organic and free-range farming argue that cows’ emissions can be offset by allowing them to graze – which encourages grass to grow and thus helps lock, or “sequester”, atmospheric carbon back into the soil.
So do free-range cows cause more climate change than they prevent? Field experts think they have the answer.
A collaborative report by the Food Climate Research Network has analysed the available studies – and concluded that grass-fed animals are, like their more intensively-reared cousins, still net contributors to the climate problem.
Speaking in a webinar this week, the report’s lead author, Dr Tara Garnett, made the following observation: “Sequestration really doesn’t do very much to address the question of livestock related emissions”. In fact, its impact is “miniscule”, she said.
When it come to mitigating agriculture’s contribution to climate change, the only reliable answer is to eat less. “People shouldn’t assume that their grass-fed steak is a climate change-free lunch. It isn’t,” Garnett said in a press statement.
Grazing can help extract carbon from the atmosphere by encouraging grass to grow and put down deep roots, which can eventually transform into a form of carbon that stays buried beneath the ground. But the report found there are many factors that can interrupt and limit this process: from excessive rainfall and drought, to thin or insufficiently fertile soil, to a high density of livestock.
All these conditions can reduce grazing’s ability to sequester carbon, the report argues. And while some research – such as that conducted by proponents of Allan Savory’s “carbon ranching” – show high levels of carbon sequestration in grazed land, these results are not supported by the peer-reviewed studies. In fact, non peer-reviewed work often fails to factor in the animals’ own emission contributions, Garnett says.
Ultimately, it just doesn’t look like it is possible to meet present global demand for meat and dairy in a way that is environmentally sustainable. Even if we limit livestock production to land unsuited to cropping or feed animals only on food-waste products, Garnett suggests, that still wouldn’t provide anywhere near enough protein to meet current consumption levels. In fact it would only provide around 13g of animal protein per person per day – which falls far short of the 57g currently consumed by people in high income countries.
But this doesn’t mean that grassfed options should be shunned. For while the report addressed the question of grazing livestocks’ net contribution to greenhouse emissions, they did not compare these to emissions from animals raised in more intensively-farmed, feedlot systems.
This means it is still difficult for those consumers who want to continue eating animal products, to know which production system is best for the planet.
Intensive systems, for instance, demand more crops to be grown to feed the livestock. This encourages the conversion of grassland or forest to cropland, and releases carbon straight into the atmosphere when the soil is exposed to the air at harvest.
The Food Climate Research Network hope to clarify this comparison with a future report looking at grazing’s impact on biodiversity. The authors also stress that there may be other reasons why grassfed is the preferable ethical choice – from considerations of people’s livelihoods and jobs, to animal welfare, biodiversity, food security and nutritional value.
Further comparative research on emissions is also required. For while there may be no such thing as a “climate change-free steak”, consumers still need better guidance from government in navigating the emissions balances that are being struck by different farming systems. Anything less would be a cow-ardly retreat from the climate change challenge.