CLIMATE EFFECTS OF MEAT AND DAIRY PRODUCTION
Climate effects of meat and dairy production
Dr John Lynch and Prof Ray Pierrehumbert
Agriculture is responsible for a significant and increasing proportion of anthropogenic greenhouse gas (GHG) emissions. Livestock farming is particularly emissions intensive, and concerns have been raised that the growing demand for animal products may prevent us from staying within our climate targets.
Livestock systems are associated with a range of GHG emissions, most importantly methane from enteric fermentation and animal manures, nitrous oxide from fertiliser and manures, and carbon dioxide from energy generation and land use changes. The metrics currently used to aggregate GHGs and report the total climate impact of different activities are ill-equipped to assess livestock farming, however. Different GHGs are typically expressed as ‘carbon dioxide equivalents’ using the 100-year Global Warming Potential metric, but this can obscure important differences between the warming effect and atmospheric lifespan of each gas. We use climate modelling approaches and alternative metrics to appraise the global warming caused by livestock, and test how changes to the food system might contribute to or mitigate climate change. Such approaches enable us to better measure and improve the sustainability of our food systems, and provide important insight into the consequences of livestock production.