Dairy farming and climate change
The demand for animal products such as milk, is increasing globally, and in the future this need must be met by a higher production of milk and meat. At the same time farmers are faced with the challenge of finding ways to raise and keep their cattle in a sustainable and environmentally friendly way. So what problems are farmers facing in the cattle and the dairy cow sector?
Direct negative effects on the climate from dairy farming include the emission of enteric methane that arises from the digestion of plant material within the cow; or methane emission from manure, where similar fermentative processes continue even after the digestive process is complete (you will cover this topic in more detail later).
Ruminants only use a fraction of the nitrogen they ingest with their food; a lot of it is excreted in their faeces and urine, which is often transformed into nitrous oxide (N20) – a very potent climate gas. N20 is also released from plant fertilisers and the production of feed for ruminants is responsible for another large proportion of greenhouse gas (GHG) emissions. Often, the application of fertilisers or manure management are also responsible for the pollution of soil and water.
The dairy industry relies on a large variety of processes that consume fossil fuels, for example, harvesting and transporting feed, cooling milk, transporting milk, farm work using heavy machinery, and general use of electricity.
Another, often forgotten, aspect of dairy or cattle farming that has a big impact on GHG emissions, is the change of land-use. When a forest is cut down to make space for pastures or to plant feed for cattle and dairy cows, the potential of the land to take up and hold large amounts of CO2 and serve as a carbon storage is reduced and the land can turn from a GHG sink to a GHG source. This goes hand in hand with the severe degradation of land that is used for dairy or cattle farming or growing forages.
Livestock farming competes for land-use with other agricultural sectors. As a cow grows, only about 10% of the food she consumes is converted in to meat. She requires the same amount of land to produce nutrition for one human as it takes to provide sufficient food for ten vegetarian humans. Using land to plant crops can lead to a more efficient food output (although the nutrient composition needed for a balanced diet must be considered alongside the amount of food produced).
Having examined the problems, it’s clear that the dairy and cattle sector needs to change the way it currently farms. What solutions are there for this sector? We’ll be looking at possible solutions throughout this week.
References and further reading:
- Gerber, P.J., Steinfeld, H., Henderson, B., Mottet, A., Opio, C., Dijkman, J., Falcucci, A. & Tempio, G. (2013). Tackling climate change through livestock – A global assessment of emissions and mitigation opportunities. Food and Agriculture Organization of the United Nations (FAO), Rome.
- Morison, J. I. L. and Matthews, R. B. (eds.) (2016): Agriculture and Forestry Climate Change Impacts Summary Report, Living With Environmental Change. ISBN 978-0-9934074-0-6
© University of Reading