Change in the dairy industry is vital for cutting emissions, but what are the proposed solutions?

Methane reduction from the dairy industry remains imperative for global action on climate change and for the UK to follow through on its promises made in the Global Methane Pledge. The good news is that many solutions exist and are already being acted upon.

Published

July 12, 2023

Animal agriculture has come under speculation in recent years for its environmental impact

Over a third of man-made greenhouse gas emissions come from our food production, with animal-based products contributing to 57%[i]. Some of our previous Insights have discussed the environmental challenges of animal agriculture in more detail, such as the impact of beef and leather production on deforestation and the positives of a plant-based diet.

After beef and rice, cow’s milk produces the largest amount of greenhouse gas (GHG) emissions in the food production sector at 8%[ii]. Methane, in particular, is a significant GHG emission for the dairy industry. Cattle produce methane in two ways. Firstly, the anaerobic decomposition of cow manure, when stored as a liquid, produces a significant amount of the gas[iii]. Secondly, methane is produced by ruminant livestock through enteric fermentation during their digestive process. Carbon from feeds is broken down by microorganisms in the rumen without oxygen, leading to the production of methane gas, which is subsequently burped out (eructation)[iv]. Methane has 80 times the warming power of carbon dioxide in the first 20 years after emission, and methane from all human activity contributes to at least a quarter of global warming[v].

There have been attempts to tackle this issue, for example, the Global Methane Pledge, which promises to reduce methane emissions by 30% by 2030[vi]. However, despite signing this pledge at COP26, the UK does not yet have a clear plan to achieve this goal.

Figure one: UK methane emissions (Million tonnes carbon dioxide equivalent)

Source: Department for Business, Energy & Industrial Strategy

So, what are the solutions?

One solution Green Alliance suggests in their ‘Methane Matters’ report, launched in November 2022, is shifting to a more plant-based diet. Switching from processed dairy and meat to alternative proteins, in line with the recommendations of the National Food Strategy, would reduce agricultural methane emissions by 8%[vii]. Green Alliance suggests that with investment, the UK could become an industry leader in the production of alternative proteins.

A reduction in milk consumption is, of course, not the preferred solution of the dairy industry. It is expected that by 2050, the global demand for food will have doubled[viii]. Dairy products are seen as important contributors to global food security and a reduction in poverty[ix]. Despite growth in the consumption of alternative kinds of milk[x], over 80% of the global population regularly consumes dairy products[xi]. Women own or manage about 25% of the cows in cattle-keeping households, meaning the dairy industry is a significant contributor to women’s social mobility[xii]. Improving efficiencies is one sustainability solution being heavily focused on by the industry.

About 80% of global dairy emissions come from countries with emerging dairy markets[xiii]. This is because feed quality, herd structure, and animal health and welfare impact milk yields. Lower-yielding dairies emit more GHGs than high-yielding ones[xiv]. To address this, the Pathways to Dairy Net Zero Scheme (P2DNZ) was set up in 2021 to develop sustainability pathways for dairy systems[xv]. P2DNZ is collaborating with the Global Methane Pledge and the UN Food and Agriculture Organisation (FAO) to invite ten countries with emerging dairy markets to join the scheme[xvi]. Tanzania, Kenya, Rwanda, Uganda, Uruguay, Costa Rica, Colombia, Pakistan, and Vietnam have all signed on to the programme, whilst discussions with India are ongoing. Together, these ten countries amount to over 30% of the dairy industry’s global GHG emissions[xvii]. The plan is to use a three-step process to reduce their emissions: changing the existing dairy practices used, scaling existing and emerging technologies, and long-term research.

Another way to reduce methane emissions is better management of slurry. ‘Slurry’ is the dairy industry term for manure. For example, in the UK, Green Alliance estimates that two slurry management techniques could reduce at least 4% of agricultural methane emissions[xviii]. The first is adding acid to slurry, which can cut the methane emissions of this source by over 80%[xix]. This technique also leads to the creation of improved fertiliser. The second technique is capturing methane from slurry pits and converting it to biogas to use as energy on the farm or sell as another source of revenue. These techniques will also help to reduce nitrogen pollution in rivers, which can lead to eutrophication. Eutrophication occurs when an overabundance of nutrients, such as nitrogen, leads to algae blooms that block sunlight, preventing plants from being able to photosynthesise. The number of microbes increases to decompose the dead plants, which reduces the water's oxygen levels, leading to dead zones.

There are a range of methane-reducing supplements that can be fed to cattle. Bovaer/3-NOP has been assessed by the Climate Change Committee and deemed as a cost-effective measure that could cut 40% of methane emissions produced by dairy cows[xx]. It would only cost the average consumer an additional 33 pence per year ($0.42 USD) if the supplement were used across the UK herd[xxi]. However, Bovaer has not yet been approved by the Food Standards Agency. Seaweed is another strategy that has been tested to reduce methane emitted by cattle in recent years. In 2018, the first research was conducted that fed seaweed to live cattle rather than in a lab. They found that seaweed does not affect the taste of milk[xxii]. More recent research has found that feeding a small quantity of seaweed to cattle over five months leads to an 82% reduction in methane that they belch out[xxiii].