Mitigating climate change: the role of domestic livestock

Abstract

Livestock contribute directly (i.e. as methane and nitrous oxide (N 2 O)) to about 9% of global anthropogenic greenhouse gas (GHG) emissions and around 3% of UK emissions. If all parts of the livestock production lifecycle are included (fossil fuels used to produce mineral fertilizers used in feed production and N 2 O emissions from fertilizer use; methane release from the breakdown of fertilizers and from animal manure; land-use changes for feed production and for grazing; land degradation; fossil fuel use during feed and animal production; fossil fuel use in production and transport of processed and refrigerated animal products), livestock are estimated to account for 18% of global anthropogenic emissions, but less than 8% in the UK. In terms of GHG emissions per unit of livestock product, monogastric livestock are more efficient than ruminants; thus in the UK, while sheep and cattle accounted for 32% of meat production in 2006, they accounted for , 48% of GHG emissions associated with meat production. More efficient management of grazing lands and of manure can have a direct impact in decreasing emissions. Improving efficiency of livestock production through better breeding, health interventions or improving fertility can also decrease GHG emissions through decreasing the number of livestock required per unit product. Increasing the energy density of the diet has a dual effect, decreasing both direct emissions and the numbers of livestock per unit product, but, as the demands for food increase in response to increasing human population and a better diet in some developing countries, there is increasing competition for land for food v. energy-dense feed crops. Recalculating efficiencies of energy and protein production on the basis of human-edible food produced per unit of human-edible feed consumed gave higher efficiencies for ruminants than for monogastric animals. The policy community thus have difficult decisions to make in balancing the negative contribution of livestock to the environment against the positive benefit in terms of food security. The animal science community have a responsibility to provide an evidence base which is objective and holistic with respect to these two competing challenges.

Adaptation to climate change – exploring the potential of locally adapted breeds

“…However, when considering GHG emissions from enteric fermentation, account should be taken not only of the gross efficiency of converting feed inputs to human food, but also of differences in species' ability to use forages and by-products that cannot otherwise be used by humans. Gill and Smith (2008) propose using 'human edible return' as another indicator to assess livestock efficiency. Recalculating efficiencies on the basis of human-edible protein balance indicate higher efficiencies for ruminants and grassland-based systems than for monogastric animals or concentrate-based systems (Council for Agricultural Science and Technology (CAST) 1999; Gill et al, 2010; FAO, 2011a).…”

“…Gill and Smith (2008) propose using 'human edible return' as another indicator to assess livestock efficiency. Recalculating efficiencies on the basis of human-edible protein balance indicate higher efficiencies for ruminants and grassland-based systems than for monogastric animals or concentrate-based systems (Council for Agricultural Science and Technology (CAST) 1999; Gill et al, 2010; FAO, 2011a). More research also needs to be done on the role ecosystem services play in improving or restoring agricultural production systems or where possible 'tipping points' of ecosystem functions may occur.…”

Policy options in addressing livestock’s contribution to climate change

“…Technical options are also available to mitigate gaseous emissions of intensive systems (UNFCCC, 2008;Gill et al, 2009), which are mostly related to manure management (pig, dairy and feedlots) and enteric fermentation (dairy and feedlots). Anaerobic digestion allows CH 4 emissions from animal storage to be reduced whereas at the same time producing biogas that can substitute for fossil fuel energy.…”

“…For example, as stated in a report from the Second European Climate Change Programme (European Commission, 2005): 'The GHGs emission trends observed are for the most part due to the side-effect of structural changes or Common Agricultural Policy or the implementation of water protection legislation, and not to specific climate change measures in the agricultural policy area. ' There is a substantial potential to reduce the sector's contribution to climate change through policies that foster the adoption of a wide range of technologies and management -E-mail: pierre.gerber@fao.org practices that are available to reduce emissions from livestock farming and to increase carbon sequestration in agro-pastoral systems (Gill et al, 2009). However, a widespread adoption of these technologies faces a number of challenges stemming from the large number of livestock holders often owning a small number of animals, the great diversity of livestock production systems, each requiring adapted technical packages and policy instruments, and the wide variation in agro-ecosystems.…”

Animal health aspects of adaptation to climate change: beating the heat and parasites in a warming Europe

“…Livestock are also central to the Food Security and 'Sustainable Intensification' agendas (Beddington, 2011), that is, the requirement for increased food production, with less waste and environmental impact to feed a growing world population, estimated to reach 9 billion by the 2050s. Demand for meat and dairy products, in particular, is projected to increase markedly as the developing world becomes more affluent (Gill et al, 2010;Thornton, 2010).…”