Carbon dioxide is the most significant contributor to human-induced climate change but methane is a close second, according to the UN’s Intergovernmental Panel on Climate Change (IPCC).
While it lasts in the atmosphere for less time than carbon dioxide, methane is about 28 times more potent at trapping heat. Cutting methane emissions can therefore be one of the quickest and most effective ways to limit greenhouse gases in the short term.
Some 40 per cent of the world’s annual methane emissions come from agriculture, the bulk of which is from livestock. Cows are by far the biggest culprits, emitting the gas largely through their burps — rather than flatulence, as commonly thought. Administering methane inhibitors to cows can help clean up bovine burps and thereby reduce emissions — without the need to make drastic cuts to livestock production and beef consumption.
Cows and other ruminants produce methane during digestion, in a process known as enteric fermentation. Inhibitors, which disrupt methane production in the gut, are now proving a promising technology for addressing the climate impact.
How does it work?
Ruminant animals, such as cattle and sheep, have a pre-stomach or rumen, in which trillions of microbes ferment the animals’ food into molecules that can be absorbed as a source of energy and nutrients. A specific group of these microbes, known as methanogens, produce methane, using hydrogen and carbon dioxide, in a process that makes digestion more efficient. But this methane is not absorbed. Instead, the animals burp it out into the atmosphere. Inhibitors work by disrupting the methane production process, or methanogenesis.
These inhibitors can come in various forms, such as feed additives or vaccines. Feed additives, including 3-NOP (3-nitrooxypropanol) and red seaweed, are mixed into the cow’s diet and interfere with the enzymes that facilitate methane production. Vaccines, still largely in development, are designed to stimulate the cow’s immune system to reduce the population of methanogenic microbes in the stomach.
What are the pros and cons?
Reducing the amount of methane cows belch into the atmosphere has the potential to significantly curb emissions of the gas, thus mitigating human-induced climate change. Some studies also suggest that methane inhibitors can also improve feed efficiency, meaning cows convert feed into body mass more effectively.
Perhaps the biggest appeal of methane inhibitors, though, is that they reduce emissions while avoiding any great upheaval for the meat industry and meat eaters. But this convenience is offset by a gamut of other issues.
Even the most promising inhibitors — red seaweed and 3-NOP, marketed as Bovaer — produce variable results. Test tube studies looking at Asparagopsis, a specific type of seaweed, have found that it can reduce emissions by up to 99 per cent. But, in a study carried out by Meat and Livestock Australia on Wagyu cows, emissions were cut by only 28 per cent. The synthetic feed supplement 3-NOP similarly reduces the amount of methane produced by about 30 per cent. The breed of the cow and the rest of its diet will determine how effective inhibitors are.
Both forms of inhibitor also pose regulatory problems. The methane-inhibiting compound in Asparagopsis, called bromoform, is an animal and potential human carcinogen. Studies suggest 3-NOP could be carcinogenic, too. Current trials show no significant traces in meat or milk produced from cows receiving the supplements. But, in order for these to meet regulatory standards, “you need super extensive testing . . . you need way longer trials than what we have now”, says Mario Herrero, professor of sustainable food systems and global change at Cornell University, and lead author of the IPCC special report on climate change, food security and land.
Farming seaweed to produce additives for feed is expensive, as well — a cost that will ultimately fall on farmers, according to Herrero. Made in a lab, 3-NOP is simpler to produce, he says — but it is still pricey and trials suggest it becomes less effective over time.
“The rumen adapts,” explains Herrero. “If you feed it some nasty thing that prevents it from functioning in the way that you want, it starts adapting with time.”
Will it save the planet?
Given that livestock farming accounts for 32 per cent of human-induced methane emissions, according to the UN, these inhibitors can make a meaningful difference. However, they are not a silver bullet. Other changes are needed, says Herrero. For example, livestock in poorer countries are currently woefully underproductive. With demand for animal protein growing as populations increase and incomes rise, this needs to change in order to make the global food system more sustainable, says Herrero. Producing six litres of milk from one cow instead of two would help to reduce emissions.
Has it arrived yet?
The 3-NOP supplement has approval for commercial use in Brazil, Chile, Australia, the UK, and the EU, and is already used by dairy producers such as Bel Group, Valio, and Arla Foods. However, many potential solutions, especially vaccines, are still in the research and development phase.
Who are the winners and losers?
As new regulations oblige agricultural and food companies to pay for the indirect ‘Scope 3’ emissions in their supply chains, products such as methane inhibitors will become increasingly essential tools. That could prove lucrative for the biotech and agricultural companies that come up with the most effective, commercially viable solutions.
Meat-eating consumers may also be able to dodge the pressure to change their diets if methane inhibitors prove effective — despite increased scrutiny of the livestock industry for its environmental damage, and calls for less meat consumption.
However, traditional livestock feed suppliers that do not adapt to the new demand for methane inhibitors may lose market share. Even in rich countries, small-scale farmers may struggle to pay the high costs associated with the new technologies. In other parts of the world, farmers simply will not have access to them.
Who is investing in it?
Universities and research centres are at the forefront of studying and developing new methane-inhibiting technologies, while governments are funding research and providing incentives for sustainable agricultural practice.
But the big investment now, and in the future, will come from biotech and agricultural companies such as DSM and Cargill, which stand to gain most from slashing emissions from livestock without slashing meat production.
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