Study Examines Livestock, Global Warming Link

HALIFAX, Nova ScotiaNew research from the Dalhousie University examining how much individuals collectively consume and the environmental impacts of food choices raises questions about consumption and production in food systems, particularly in the livestock industry.

Focusing on the global livestock industry, the paper explored the relationships between projected growth in livestock production and worldwide sustainability thresholds for human activity as a whole. Published in the October 2010 edition of the Proceedings of the National Academy of Sciences, the paper focused on three domainsgreenhouse gas emissions, reactive nitrogen mobilization and appropriation of plant biomass.

The research focused on the 50-year period between 2000-2050. Using published data of the environmental impact of livestock production from the year 2000 and projections of livestock production and consumption from the United Nations Food and Agriculture Organization, the authors were able to estimate the potential environmental impacts in the 50-year period.

It is estimated that global production of livestock will double in the next 50 years, which will in turn, greatly increase the environmental impacts of the livestock industry. The researchers estimated the livestock industry alone will account for 72 percent of humanitys total safe operating space" for anthropogenic greenhouse gas emissions; 88 percent of safe operating space for biomass appropriation; and nearly 300 percent of the safe operating space for reactive nitrogen mobilization.

Nitrogen plays a pivotal role in both natural and agricultural ecosystems. An abundance of nitrogen can lead to ecosystem simplification and a loss of biodiversity as well as contribute to global warming, acid precipitation and eutrophication of bodies of water. Industrially-fixed nitrogen is a large component of commercial fertilizer but it is estimated that only 10 percent to 20 percent of the nitrogen applied to crops actually is consumed by humans. The remainder is lost to the environment. While reactive nitrogen is not directly used in livestock production, it is used to fertilize the crops and pastures that feed livestock.

It is estimated that nearly 60 percent of the biomass currently harvested annually to support all human activities is consumed by the livestock industry. This underscores the dependence of this industry on biological productivity and raises some serious questions about the sustainability of devoting such a large portion to the livestock industry.

The researchers noted

The researchers also examined similar environmental projections that explore the implications of a shift away from livestock production to a more low impact source of protein such as poultry or soybeans. The authors stressed a total switch to poultry or soybeans is unrealistic, even a marginal decrease in livestock production would help to reduce environmental impact.