'Global warming' and 'climate change' have become familiar household terms. However much
confusion prevails over the role of livestock in these issues where an incomplete
evidential foundation is often influenced by politics as much as by science. Climate change has
entered the public debate globally. It is having severe social, economic and environmental
effects through rising sea levels, changing weather patterns, temperature rises and changes
in disease and vector distributionthat will challenge society through compromised food
production and water availability. International policy aims to lower the greenhouse gas
(GHG) emissions that are thought to be responsible for climate change. Adaptation of
our agricultural systems to adapt to the experiences of climate change will
be needed.
Livestock activities have the potential to impact virtually all aspects of the environment,
including air and climate change, land and soil, water and biodiversity.
Climate change
Livestock farming is responsible for around 3.5% of total UK GHG emissions and the sector has
been tasked with reducing emissions in line with national and international agreements. A failure to reduce emissions
would require larger cuts to be made in other areas, which is unlikely to be acceptable to governments
and those industries involved. Cattle farming results in the production of three of the four
principal gases with global warming potential (GWP): carbon dioxide (CO2), methane (CH4) and nitrous
oxide (N2O).
The most significant sources of GHG are the methane produced during enteric fermentation which is
released when animals eructate and the methane and nitrous oxide released from mineral fertilizers,
slurry and manure (both when stored and spread). However, emissions are also generated from fuel and
electricity produced from fossil fuels used for equipment and machinery on farm, and the
production and transport of inputs and milk and milk products.
Soil
The banks of water courses, ponds, lakes and canals become poached and eroded over time if animals
have direct access. This reduces water quality by adding silt and faecal contamination and has the
potential to increase phosphorus levels. Land degradation involves similar poaching of grazing land,
feeding areas, gateways and tracks. Consequences include loss of organic matter, nutrient
leakage, reduced fertility and erosion.
Water
Both ground and surface water may become contaminated either by a single accidental event e.g. slurry discharging
into a river, or from the cumulative unintended consequence of agricultural activity over a prolonged time period.
A range of different pollutants can potentially contaminate water; most commonly nitrogen and phosphorus but
there is also a need for the careful management of agrichemicals such as veterinary medicines,
dairy chemicals, disinfectants, pesticides, herbicides and fuels. Water and soil pollution can be linked to
antimicrobial resistance (AMR) as cross-resistance occurs with heavy metals and disinfectants.
Biodiversity
Farming practices may have a huge impact on biodiversity as, almost by definition, most agricultural
practices are trying to selectively exclude growth of other plants and pests.
A variety of methods that can result in a reduction in the impact of livestock farming on
the environment include:
- Resource efficiency
- Nutritional management
- Improving health and welfare (through reducing the waste of disease)
- Genetics and reproductive efficiency
Public good
Livestock farming contributes to the public good, as farmers actively and selectively
manage natural landscapes, and their livestock convert natural resources into a
valuable source of proteins, minerals and vitamins for human health and wellbeing as
part of a balanced diet. Livestock farming also strengthens rural communities and
provides employment and societal cohesion in often marginal and under-developed parts of
countries globally. They key here is for regenerative and sustainable farming practices
to work in tandem with the careful stewardship of natural resources.