How much is Canada’s beef and dairy herd currently contributing to global warming? The answer may come as a surprise: over the last dozen years the herd’s direct impact on the planet has been one of slight cooling!

Yes, beef cattle and dairy cows emit lots of methane; and yes, methane is far more powerful than carbon dioxide in terms of its ability to trap heat in our atmosphere. However, methane is more fleeting than carbon dioxide. On average the former breaks down after about 10 years; the latter persists for hundreds of years before most of it is absorbed by land or sea. This means the warming impact of methane is largely determined by changes in the rate of increase or decrease in emissions.

Since Canada’s emissions from “enteric fermentation” — the digestion process through which cows burp out methane — have declined by 21 percent over the past 12 years, the sink has outweighed the source: that is, more methane is breaking down than being emitted. This trend helps to cool, not warm, the planet — for as long as it can be sustained. (Emissions from livestock manure in Canada, made up of methane and nitrous oxide, have also declined over this period, by 10 percent.)

Now, before you go out and slam down a victory burger and shake, it is worth considering why emissions have declined and whether these trends are likely to continue. One reason for the decline is efficiency gains from technological and genetic improvements. The Canadian dairy sector is a prime example: although the typical dairy cow in Canada now emits 20 percent more methane than the typical dairy cow in 1990, it produces 46 percent more milk. The sector’s net change in methane emissions over that time has been a decline of 17 percent.

However, another major driver of reduced emissions, perhaps the main driver, is a reduction in the overall size of the herd. The dairy cow population has declined by 31 percent since 1990, and the beef cattle population has declined by 28 percent since 2005, thanks in large part to a drop in market prices after the BSE outbreak. While efficiency gains have helped reduce the total herd, so has reduced demand for beef and dairy. Domestic per capita demand for red meat has declined from its peak in the early 1980s, driven by dietary shifts toward more moderate consumption (changing demographics, tastes and attempts to avoid saturated fats are more responsible for the drop than increases in the number of vegetarians or vegans who avoid meat entirely). Meanwhile, total commercial sales of milk in Canada peaked in 2009, while in per capita terms milk availability peaked in 1979.

This leads to a rather paradoxical outcome, where the two leading contributors to making Canada’s beef and dairy herd a net source of global cooling are producers of beef and dairy improving their management practices, on the one hand, and people who have reduced the share of beef and dairy in their diet, on the other.

Are these trends likely to continue? All signs point to yes. A number of transformative technologies are currently being tested that could significantly reduce methane emissions from cattle.

Feed supplements for cattle have shown very promising results during testing, in some cases reducing methane by upwards of 25 percent. Other firms are testing devices that can be worn by cows, sitting above the nose and quietly oxidizing 85 percent of the emitted methane. In the dairy sector, biogas digesters are becoming far more common; these capture methane from manure and convert it into carbon-neutral electricity. Meanwhile, there is growing interest in adopting new grazing management practices that maximize the amount of carbon dioxide that is sequestered into the soil (thus helping offset the net warming impact of emissions above ground). Beef and dairy producers across Canada, both large and small, are clearly taking steps to tackle climate change in various ways.

Changing consumption trends also indicate that Canadian consumers are switching out a portion of their beef and dairy for plant-based alternatives, and it’s likely this trend will also continue. Again, this is mostly driven by people who eat meat and dairy, but who have expressed interest in reducing their overall consumption of animal-sourced foods for one reason or another. From a global climate equity point of view, this is arguably a positive development: Canadians consume about twice as much beef and dairy as the world average.

We know that the Earth can sustain a significant number of large methane-belching ruminants (consider the massive herds of tens of millions of bison that once grazed the great plains of North America, sustainably managed by Indigenous peoples for millennia). However, the number of domesticated livestock around the world today is orders of magnitude larger than the number of wild animals before industrialization. Despite declining cattle numbers in OECD countries and transitioning economies in recent years, the total number of cattle globally continues to grow — and that trend is not sustainable.

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With some 46 million hectares of arable land (about 3.3 percent of the world total), Canada should aim to produce enough food to feed a similar portion of the global population. This means producing enough food to feed its own population seven times over — all while bringing the sector’s carbon dioxide emissions to zero and reducing methane and nitrous oxide emissions to more sustainable levels. By consuming more moderate amounts of beef and dairy (meaning a bit less than the current average of 18 kilograms of beef per year and 66 litres of milk per year), Canadians can help to reduce some of the pressures on agricultural land, while also freeing up more beef and dairy for export to help reduce the need for ruminant production abroad.

At the same time, it would be unwise to ditch beef and dairy altogether, and it’s worth thinking carefully about which protein alternatives are being consumed in its place. Aside from the economic, cultural and nutritional benefits of beef and dairy, cattle production in Canada can do good for the planet. In the same way that bison fertilized the prairie soil in times past, supporting carbon storage, nutrient cycling, water retention and biodiversity, properly managed cattle today are in some respects helping to protect Canada’s endangered grassland ecosystems.

A portion of the land used for grain crops to produce feed for beef finishing and dairy could be shifted over to production of human-grade protein crops, but there are also limits to how much of a shift is advisable. Canada is already a major producer of plant-based-protein crops — legumes and pulses like soy, peas, lentils and chickpeas — and considerable energy and capital is being invested into increasing yields. These nitrogen-fixing crops offer a great natural way to fertilize the soil, but they are typically annual crops that work best as part of a larger crop rotation, planted once every few years, interspersed with cereal grains such as wheat or barley. Perennial agricultural production, which includes cattle grazing and crops that do not have to be changed each year, is a better way to keep carbon sequestered. The recent shift by many farmers to annual crop production has led to a major decrease in the carbon stored in Canada’s agricultural soils — which means an increase in carbon being released into the atmosphere.

In theory a reduction in the production of grain for animal feed could help reduce agricultural emissions. However, a certain portion of spoiled or damaged grain crops intended for human consumption will end up being diverted to the livestock supply chain anyway. Here and in other ways, livestock play an essential role in reducing food loss and waste, which itself is responsible for an astounding portion of global GHG emissions (the Intergovernmental Panel on Climate Change reports global food loss and waste contributes 8 to 10 percent of total anthropogenic emissions).

Of course, the decision about whether to consume meat and dairy is a personal one, and based on much more than just the environmental impacts of production. For a small portion of Canadians, the “use” of animals for human benefit — particularly in the dairy sector — is seen as unacceptable; whereas for others (a significant majority), humans have always benefited from animal foods and the idea of entirely giving up meat and dairy is equally unacceptable. For some Canadians the relatively high presence of saturated fats is enough to warrant lower consumption of meat and dairy, whereas for others it is seen as perfectly healthy if consumed in moderation. From an environmental point of view, it does make sense to reduce the share of animal proteins in the average Canadian diet. At the same time, there are good environmental reasons to keep ruminants in the agri-food system.

Arguments calling for people to cut out red meat and dairy for the sake of the climate are usually based on the global average GHG footprints for beef or milk, which are far higher than Canadian production averages, and are problematic in the way they equate methane with carbon dioxide equivalents.

Such arguments do tell a particular truth: that cattle are significant emitters of powerful greenhouse gases. But they omit some of the broader context that tempers that truth: that cattle play an important role in Canada’s agri-food system; that their emissions are on a declining trend; and that consumption of beef and dairy is falling too. Viewed holistically in this way, the environmental case for reduced but moderate beef and dairy consumption is compelling.

Photo: Shutterstock, by Joseph Holoien.