Headlines such as ‘cow burps are warming the planet’ have dominated the media recently, bringing livestock farming, and - in particular - methane produced by ruminants, to the forefront of the global warming crisis.
Cattle farming is cited as a major contributor to climate change through impacts on global warming and the environment. But how bad is it?
Although it's clear that livestock agriculture is contributing to the climate crisis, global warming is a highly complex and multi-faceted issue needing holistic and considered solutions, says veterinary surgeons Hannah Davies and David Black from Vet Sustain.
With a growing global population, now reaching over eight billion, it's important that we consider how farmers, as custodians of the land and integral to our global food systems, can be part of regenerative and sustainable solutions.
Why is cattle farming so bad for the environment?
Since the end of the Second World War, schemes to industrialise agriculture in a bid to produce cheaper food have had a significant impact on the environment.
Farming on a greater scale, promoting monoculture, increasing the use of pesticides and fertilisers, and removal of hedgerows and other wildlife habitats have understandably contributed to a decline in biomass and diversity (Raven and Wagner, 2021).
This intensification of cattle farming has resulted in larger farms with more cows - and as we know, more cows means more methane.
What is methane?
Methane, along with carbon dioxide, nitrous oxide and F-gases are known as greenhouse gases. These gases contribute directly to climate change through global warming, as they act to trap heat in the earth’s atmosphere.
Methane, made up of 1 carbon atom and 4 hydrogen atoms, has many sources including extraction and burning of fossil fuels, agriculture, wetlands and decomposition of landfill waste.
Methane from ruminant agriculture is cited as the major contributor to global warming and climate change, responsible for 40-45% of global greenhouse gas emissions (Meale et al, 2012) and 47% of UK methane emissions (DEFRA, 2022).
How does methane compare to other greenhouse gases?
It's challenging to compare the direct impact that these different greenhouse gases have on global warming as they all behave differently when emitted into the environment.
How long does methane last in the atmosphere?
Methane is a potent greenhouse gas, 28 times more potent than carbon dioxide over a 100 year period. However, importantly, the warming effect of methane is short-lived, degrading in the atmosphere within 12 years compared to carbon dioxide, which remains for centuries.
This means that increases in methane will have a rapid, significant effect on global warming, but a reducing methane output will, conversely, quickly contribute to global cooling; a decline of any methane source at a rate of more than 0.3% per year is all that it would take.
The UN wants a shift away from outsized meat and dairy industries, especially in high-income countries.
How can cattle farmers reduce methane?
Per gram of protein, ruminant meat has the highest average global carbon footprint, many times greater than plant-based foods.
Therefore, a gradual reduction of total global livestock numbers alongside improved health, welfare, lifespan and productivity are important. This, alongside sustainable farming with a regenerative mindset, 'sinking' carbon back into trees, crops and soils, means that farmers are instrumental in reversing climate change.
Per gram of protein, ruminant meat has the highest average global carbon footprint, many times greater than plant-based foods.
However, global GHG emission averages can mislead and do not represent the impact of local agriculture – for example, the carbon footprint of UK milk production is less than half the global average.
Carbon footprint varies greatly depending on location and production system used, and comparing the carbon footprint of different foodstuffs is complex due to their varying nutritional composition and health benefits (e.g. a beef burger has a very different protein and amino acid profile to a plant-based burger).
How do cows produce methane?
Cattle, sheep, goats, deer and camels are ruminant animals. Ruminants are characterised by their digestive system, which consists of four stomachs, allowing them to ferment their food.
This fermentation process creates methane, which is then belched out or excreted with their faeces. The methane produced from agriculture is largely from this enteric fermentation process. However, it is important to note that this source of methane is part of the biogenic carbon cycle, and is not adding ‘new’ carbon to the atmosphere, unlike fossil fuels, which are.
Could we feed cows differently to reduce methane?
Feeding and nutrition are important to minimise methane without impacting health or production. There are feed additives such as saponins, condensed tannins or essential oils that can reduce methane production.
A commercial product is becoming widely available across Europe named Bovaer, which contains a compound called 3-NOP, which targets one of the key enzyme pathways in the rumen. There is also optimism for the addition of red seaweed in cattle diets with trials indicating reductions of between 60 and 98% – research is ongoing.
Most recently, scientists have proposed that genetically modifying the rumen microbes themselves using CRISPR technology could be another angle to reduce methane production.
What can farmers do to help the environment and biodiversity?
As demand for meat and milk protein increases, driven largely by aspiring developing countries, farming has a fundamental role in future food security.
Farmers, as custodians of our rural land spaces, are integral to this through employing efficient, sustainable and regenerative farming methods.
'Regenerative Agriculture’ is a commonly used term, referring to a mindset based on six core principles:
- Know your farm context and goals
- Minimise soil disturbance
- Keep soil covered at all times
- Maintain healthy root systems
- Maximise diversity of organisms
- Integrate livestock
By choosing the appropriate type of farming for the location and conditions, and employing regenerative principles to improve environmental outcomes, animal welfare and human wellbeing, farmers can be part of the solution to the global climate crisis we are currently facing.
Sustainable farming systems play an essential role in tackling the climate and ecological crises, and as members of the vet-led team involved in animal agriculture, we are in a unique position to take action and inspire others.
To achieve a reduction in emissions from livestock farming, we must take a multi-pronged approach supporting initiatives such as the BVA [British Veterinary Association] UK Sustainable Animal Agriculture Policy, which states that “The veterinary profession should promote the concept of 'less and better', in which people reduce their consumption of animal-derived products whilst maintaining proportional spend to buy better, higher quality goods.”
What can you do?
Members of the public, as the end consumer, also have an important role here through taking an interest in how their food is produced and where it is coming from. It is likely that the future of farming will start to look different as we continue to face climate change and farmers will need to be prepared to engage with sustainable and regenerative farming principles.
Consumers are a powerful voice for driving these changes, choosing food that is of high welfare, locally produced, seasonal and from farms who are paving the way for a more sustainable future.
Top image @ David Black
