Cattle catalyzing climate change

Today, we’re talking burps and farts (no, not yours) as drivers of climate change

Apr 21, 2023

The alliteration 🤌

As a kid, bi-annual visits to relatives in Punjab (India) were a sacred recurrence. While parts of my family lived in the industrial towns of the state, some lived in the idyllic settings of the vast mustard fields [yeah, exactly what you visualized as you read Punjab in the last sentence - “mera pind, mere khet…” - , all thanks to Bollywood!].

Only less romantic and fragrant.

The only fragrance I felt embraced in was that of buffalo dung and urine, with whiffs of cattle belches and farts sweeping my olfactory senses away. Agriculture being the predominant purpose of life, cattle were like family members, each having a human name.

Little did I know then, my extended family was farting1 its way to heating the planet.

This was a big revelation to me since I never really thought about it. Burps and farts of cattle heat up the atmosphere.

These stinky excretions are not just mere odours but an explosion of methane (along with a few other gases in not-so-significant amounts). Methane a.k.a. CH₄ is a greenhouse gas (GHG) just like CO₂. Although CH₄concentration in the atmosphere is much lower than that of CO₂, what makes tackling CH₄ emissions important is its capacity to trap heat. Methane is estimated to trap 84x more heat than CO₂ over a 20 year period. Moreover, methane is much more short-lived in the atmosphere than CO₂. If CH₄ were a dog, CO₂ would be a tortoise - 9 to 12 years vs. >100 years! Hence, it makes sense to put some brains into reducing these emissions too while we can.

Trivia: The global warming potential (GWP) of a gas varies with the duration of its existence in the atmosphere. Since methane is relatively easily removed from the atmosphere, its GWP is ~25-30 times that of CO₂ over a 100 year period.

If CH₄emissions from animals is a thing, why focus only on cattle?

Cattle belong to a group of animals called ruminants. What distinguishes ruminants from any other animal is the architecture of their stomachs. Ruminant stomachs have four chambers while our stomachs have just one. One of the chambers of their stomachs, rumen, houses about 200 different microbes (bacteria, fungi, protozoa etc.) which help break down the ingested food into simpler forms. Methane is the largest gaseous by-product of this process which is mainly released while burping and some bits as farts and excretion.

Cattle’s rumen is the equivalent of fermentation tanks used to make beer.

If this process is common to all ruminants, which also include sheep, goat, giraffe, deer and antelopes, why do only cattle contribute to climate change?

Well, that’s just a number game. Cattle (especially cows) are bred & reared all over the world for meat, dairy and other agricultural purposes. As a consequence, the size of their global collective far exceeds the number of other ruminants, making methane emissions from the latter relatively insignificant. As per Statista, the worldwide cattle population stands at a whopping ~940 million. Some other sources cite this number to have already crossed 1 billion🧐. With India leading global milk production, it isn’t hard to guess that it’s home to ~1/3rd of the global cattle population - largest across the world.

The cow traffic on Indian roads makes much more sense now 🥴

Trivia: If cows were a country, The Sovereign Republic of Cattle would rank as the world's sixth-largest emitter, ahead of Brazil, Japan and Germany.2

Can these gaseous emissions be manipulated?

Methane production in cattle has a direct relation to the kind of food they feed on. Foods which are less digestible produce more methane than easy to digest foods do. For example, a hay & grass feed produces more CH₄ than a corn feed. In that sense, methane released is lost energy (upto 12% of total energy intake), which could have otherwise powered the cattle. Given this understanding of the problem, multiple experiments are going on to alter cattle feed and cattle’s digestive chemistry to slash their CH₄ emissions or say, increase their energy efficiency.

Mootral, a British-Swiss company, has come up with a pellet shaped feed supplement primarily made of garlic & citrus extract, which when added to cattle feed reduces cattle’s CH4 emissions by more than 30%.

Pellets from Mootral; Source: The New York Times

Companies like Rumin8, Volta Greentech and Symbrosia are working on using seaweed as a feed additive to achieve the same goal. Seaweed seems to have the potential to inhibit an enzyme in the cow’s stomach which produces CH₄. However, cows don’t seem to devour the salty taste of seaweed - their human chefs better whip up dishes that appeal to cow-ly taste buds.

Bezoar Laboratories and its likes are researching probiotics which can either be added to cattle feed or sprayed on grazing lands to reduce ruminant CH₄emissions by upto 50%.

Where’s the quantification?

If you observed, I haven’t quantified the GHG emissions from livestock anywhere in this piece yet. What we’ve explored until now are only direct cattle emissions, i.e., when you consider cattle a source, not a product (meat and dairy). However, to understand overall emissions from livestock, indirect emissions merit equal consideration. Activities like

changing land usage from forests / food crops to grazing lands / cropland for growing animal feed;
energy consumption in the production & supply of livestock feed as well as in running animal farms; and
slaughtering livestock for meat (yes, this too!) and processing & packaging thereof.

are other significant GHG emitting sources which directly tie in with the breeding and rearing of livestock.

Estimates of annual livestock GHG emissions range from 5 to 8 gigatonnes, with latest FAO reports citing livestock to contribute ~11% of global CO₂e emissions based on data from 2015.

Cattle rearing is a vicious cycle fueled by the economics of demand-supply. If the human population were to keep growing without a downward trend in the consumption of meat and dairy, it is easy to predict that the population of livestock will have to increase to fulfill the demand (unless there’s a breakthrough in sourcing the same products from a sustainable source). And that wouldn’t be cool, quite literally.

Leaving you with something worth pondering and some ideas worth considering -

Phase out meat consumption, especially red meat;
Switch to plant based proteins or alternate meats (Impossible Foods and its likes);
Going vegan, afterall, isn’t a fad; it’s logical.

Make your contribution count 🙂