Originally published in The Environmental Magazine
Methane is a key contributor to climate change. In fact, scientists estimate that 20% of the planet’s warming since the industrial revolution has been driven by this common gas.
A significant driver of increasing atmospheric methane levels is cattle.This isn’t all that surprising, given that there are over a billion cattle in the world, who each release approximately 380 pounds of methane into the atmosphere per year. All in all, estimates suggest that the methane emitted by cows and other varieties of livestock accounts for around 14.5% of global greenhouse gas emissions. This is a big deal, especially seeing as methane is twenty times more potent a greenhouse gas than carbon dioxide. That said, the former gas stays in the atmosphere for a significantly shorter period of time than the latter. Therefore, reductions in methane emissions can have an immediate effect on the rate at which Earth’s temperature is rising.
Unfortunately, despite the rise of vegetarianism and veganism in developed countries, the world’s cattle population has remained approximately steady for the past several years. This is largely due to an increasing demand for milk and meat in countries where large numbers of the populace are rising out of poverty. It’s tough to predict whether this trend will continue into the future. Assuming it does, we will be in desperate need of a strategy for reducing the amount of impact the world’s cattle are having on the climate. One such strategy might be to feed them seaweed.
Recent studies have shown shown that adding a small amount of the seaweed Asparagopsis taxiformis to the feed of lactating dairy cows can reduce their methane emissions by up to 80%. This is a pretty impressive reduction, and clearly points to the need for future research into this relatively simple method for combating cattle-fueled climate change.
However, putting seaweed into cattle feed is by no means guaranteed to be a silver bullet. The effectiveness and practicality of this technique are far from proven. All the studies (of which there are few) on seaweed-enhanced feed, have been short term. The question of whether these 80% reductions will persist in cows after an extended period spent eating a seaweed-enhanced diet, is currently unanswered. It is also unclear whether the meat and milk that these cows produce will taste the same as their equivalents from cows fed an unmodified diet. If there is any noticeable reduction in the palatability of the aforementioned products, it’s tough to imagine seaweed introduction being a viable option.
Further complicating this issue is the fact that growing enough seaweed to make a noticeable dent in cattle related methane emissions would require a herculean effort, and a tremendous amount of coastline. Despite the fact that we could achieve 80% reductions by giving cows feed consisting of only 0.5% seaweed, the billions of cows in the world require quite a lot of feed. Therefore, it might turn out that the environmental impacts of growing this additive outweigh the benefits.
The one conclusion we can come to is that further research is both warranted and needed. Determining whether farmers can factor seaweed into cattle feed over an extended period of time, without the practice losing its efficacy, will probably be the first step in this process. If that is the case, the creation and testing of various cultivation methods for Asparagopsis taxiformis will be necessary to assess the environmental impacts of its large scale production.
In the meantime, we can all take immediate action to combat climate change by reducing the amount of beef and milk we incorporate into our diets. Even replacing beef with chicken can have a significant positive effect, as chickens convert feed into meat far more efficiently than cows, and release significantly less methane into the atmosphere. Even more preferable would be abstaining from meat entirely, or during certain days of the week.