Counting sheep, and their burps, may help lower global methane emissions
In the English countryside, researchers are on a mission to shepherd in a climate-friendly flock
Every child learns at a very young age that sheep go "baaa," but much less appreciated is how much they burp too.
In fact, sheep are among the world's most prolific belchers — spewing a collective seven million tonnes of planet-warming methane into the atmosphere every year.
Reducing the greenhouse gas footprint of the world's agricultural sector is one of the key aims of the UN Climate Summit, COP28, which is now underway in Dubai — and some important work going into that is happening at farms around southern England this fall and winter.
Teams of British researchers are rounding up as many of the country's 33 million sheep as they can, to try to determine which ones are the gassiest and which are the most-climate friendly.
"We all know that methane is going to have to be reduced... and by trying to measure the methane of the sheep, [we are] looking at improving the overall efficiency of the flock and, in turn, that's going to reduce the environmental impact," said Emma Dodds, with Innovis, a livestock company focused on sheep breeding.
The Innovis team is towing a trailer with 12 sheep-sized, sealed chambers to farms around the country. Known as a Portable Accumulation Chamber, each one is equipped to measure how much methane each sheep produces during the hour they're kept isolated.
"There's definitely a lot of variation within the flocks that we've looked at so far," said Dodds.
Sheep, like cows, are ruminants, meaning they repeatedly chew and regurgitate their food as part of the digestion process. That means they produce much more methane than, say pigs, whose stomachs work more like those of humans.
While sheep also pass gas out of the, er, other end, it's what goes through the mouth and nostrils that researchers are mostly interested in.
Scientists already know that the variation in methane production between animals has a lot to do with genetics — some sheep lines are simply more gassy than others — but other factors such as diet can also make a difference.
"The estimate is that we could make cumulative changes of about one to two per cent per year by breeding over 20 years, and that could have a big impact on the industry," said Nicola Lambe, a sheep geneticist from Scotland Central College who is supervising the sheep methane studies.
A recent report by Scotland's government concluded that by breeding greener, more climate-friendly sheep, emissions could be cut by roughly 30 per cent in that country — or a third of a tonne of methane every year, significant for a relatively small place like Scotland, says Lambe.
However, scientists are also learning that producing a more climate-friendly sheep might mean trade-offs in other areas.
"If we were only going to select animals for low-methane emissions, we could make really quite fast progress," said Lambe.
"But we can't do that if it's going to have negative impacts on their health or their growth or their ability to produce lamb meat, which is why they're being kept in the first place."
Tim White, who farms the flock our CBC News team observed in the testing chambers, said the metrics gathered by the methane testers will help farmers not only breed out the biggest belchers, but, when combined with other genetic data, could help him produce a sheep that excels in other areas too.
"The better the growth rate, then the faster they're going to get to being eaten, and the fewer days they're on the planet and the less methane they will emit," said White.
"So we're looking for those animals that are producing [meat] really well, and also produce less methane."
Cattle, given their size, produce up to six times the amount of methane per animal — and contribute the lions' share of the emissions by farm animals to global warming. But sheep have the advantage of being easier to monitor.
While it can take days to gather data about cow emissions, Lambe says by using the portable chambers vast amounts of data about sheep can be gathered in days rather than months and translated into breeding programs much faster.
In Canada, some farmers have begun similar experiments with genetics on their cattle aimed at reducing methane, although the practice is still in its infancy.
New Zealand — which famously has the highest sheep-to-human population ratio anywhere in the world, at roughly five to one — is arguably leading the race to refine the perfect sheep.
Its scientists have been studying the impact of methane emissions the longest, and they built the measuring chamber now being driven around southern England.
New Zealand's government has also said it intends to introduce a targeted carbon tax on the gases that farm animals produce, requiring farmers to monitor their emissions and pay a levy on their animals, likely starting at the end of 2024.
The scheme is controversial as many farmers fear it will raise their costs and make them less competitive internationally.
Canada's patchwork system of national and provincial carbon taxes does not include emissions produced by farm animals, and farmers are currently exempted from paying the tax on fuels used on their farms.
In the U.K., many farm groups believe the methane monitoring program — funded with a £2.9 million ($5 million Cdn) government grant — will be the first step in a similar tax scheme.
At COP26, which was held in Glasgow in 2021, over 100 countries signed a global pledge to cut methane emissions by 30 per cent by 2030. However, very few provided details on how they intend to get there.
Methane is the second most plentiful, human-made greenhouse gas after carbon dioxide but its ability to trap and hold heat is up to 80 times greater. It also stays in the atmosphere longer, so shearing emissions by even a little bit can have a significant impact.
Sheep veterinarian Emily Gascoigne, who was also at the farm during CBC's visit, said she believes the end result for farmers and the public of lower emissions could lead to better, cheaper food.
"There are benefits for sheep health, and welfare benefits for the profitability of the farm, but there are also these gifts in terms of environmental efficiency as well," she said.
"So when one is thriving, you can have success with the other."
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