The Kelp Diet: Mitigating Methane from Agriculture

Author’s note: this post overviews a potentially ground-breaking strategy for reducing methane emissions from agriculture. In the broader context of agriculture and climate change, my personal views remain in full support of the human population moving towards eating as little animal meat as possible, for both ethical and climate change-related reasons. Also important to note that the kelp diet discussed below will be used for dairy cows as well as meat livestock. Vegetarianism is certainly on the rise, but the world is not likely to stop consuming dairy any time soon. I for one have a hard time imagining a world without cheese!

Can seaweed help stop climate change?

In the context of groundbreaking climate solutions, it may seem strange to compare seaweed with, for example, wind turbines- each of which carry a staggering 164 tonnes of weight to generate power from the wind. However, dive deeper into the world of kelp and you’ll learn of its many miraculous properties, one of which could help neutralize a dangerous and potent greenhouse gas emitted into our atmosphere: methane.

Livestock such as cattle, pigs and sheep are responsible for 44% of all human-caused methane emissions. Put in other words, by burping, livestock release almost as much methane into the atmosphere per year as the entire European Union. How does this happen? Well, these animals have complex microbial digestion systems that break down whatever comes down the pipe to meet their needs. This process creates beneficial byproducts for the cow- but it also creates a waste product, methane, which the animals burp out.

So why is methane such a problem for climate change?


Image source: BC Farms and Food

The Global Warming Potential of various greenhouse gases like carbon dioxide and methane is determined by two factors: how long they remain in the atmosphere, and their ability to absorb energy. Methane’s lifetime in the atmosphere is much shorter than that of carbon dioxide, which is why CO2 poses such a threat to our climate. Moreover, methane from animal agriculture also only comprises 5% of the total greenhouse gases emitted by the United States. Much, much more comes from CO2. However, when looking at just a 20-year time period, studies from the IPCC have found that methane is in fact 86 times more potent than CO2. Meaning, in the short term, methane has the ability to warm our earth by 86 times as much as CO2!

Notably, the main component of ruminants diet, grass, is considered actually relatively inefficient for the animals to digest. This results in more methane burps than alternative diets. This fact is well known by scientists, and thus for years scientists and policymakers have been looking at different ways to alter the diet of ruminants to lower the methane they produce. However, the great challenge has been how to do this in an ethical and sustainable way, that doesn’t alter milk or meat quality.

Up to 12% of what cows eat is lost to methane production.”

Asparagopsis Taxiformis

Asparagopsis taxiformis. Image Source: ABC

 In 2015, scientists in Australia encountered a breakthrough in ruminants’ diets by experimenting with a type of tropical seaweed called Asparagopsis taxiformis. Known to be a favorite seaweed of the Hawaiian diet, Asparagopsis is grown on reef edges where water is consistently in motion The scientists discovered that this form of algae had the capacity to lower the production of methane by 99%. However, this initial research was done in a lab- and therefore needed to be applied to animals to ensure efficacy in methane reductions. Just a year later in 2016, Australian scientists did just that, and soon discovered

The addition of dried seaweed to just 2% of sheep and cattle feed could lower methane emissions by over 70%”.

What exactly is the relationship between Asparagopsis taxiformis and the methane produced by cows’ digestive systems? This type of seaweed produces a compound named bromoform, which prohibits the production of methane by reacting with Vitamin B12 during digestion.

This was a brilliant scientific discovery and has the potential to fundamentally alter the link between livestock and methane emissions. And yet thinking about the 1.2 billion cows currently being raised as livestock globally, that is a lot- and I mean a lot- of kelp needed to have a real effect on methane burps. How to grow and cultivate this much kelp remains the key challenge to scaling up this groundbreaking strategy for mitigating methane emissions. Scientists such as Alexander Hristov point out that “to be used as a feed additive on a large scale, the seaweed would have to be cultivated in aquaculture operations- harvesting wild seaweed is not an option because soon we would deplete the oceans and cause an ecological problem.”

However, most experts are still confident the kelp diet is possible and could be a significant breakthrough for mitigating methane. According to Future Feed, an Australian research team focused on Asparagopsis taxiformis, “millions of tons of seaweed are already cultivated and harvested each year, so it should be possible to grow this seaweed as well.”

Image Source: Washington Post (Original Image: Sea Forest)

Another challenge is longevity: in an interview with OnPasture and Alexander Hristov, dairy nutrition expert at Penn State, Hristov commented that adding seaweed to ruminant’s diets has been proven effective in the short term, but there is still much uncertainty about long-term effects. For instance, many cow feed additives in the past have been adapted to by their digestive microbes and effectiveness just disappears. Therefore, more longer-term studies on the kelp diet are needed.

In an interview with the Washington Post, Ana Wegner, one of the team continuing this important and exciting work at the University of the Sunshine Coast in Australia says- “We know the chemical composition of Asparagopsis and we know the chemical compounds that actually reduce methane production in cows, so now we want to maximise the concentration of that chemical so we can use less seaweed for the same effect.”

In addition to building massive machines of steel and silicon (and don’t get me wrong, we absolutely need wind and solar!), wouldn’t it be quite something if we could harness the great power of seaweed to help fight climate change? I for one can’t wait to see what science further uncovers for this climate solution- while allowing us the great privilege of enjoying that gruyere.


Watch this excellent video on the kelp diet from CBC News:

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