Raymond Pierrehumbert
Halley Professor in Atmospheric, Oceanic and Planetary Physics
University of Oxford, UK
Faculty of Science Honorary Doctor 2015

Is unrestricted beef production compatible with keeping global warming under 2C?

Time and place
Friday 25 September 2015, 11.15
Room C609, Arrhenius Labo0ratory, 6th floor

Agricultural activities have a profound adverse effect on the environment, not least via their contribution to the greenhouse gas emissions that cause anthropogenic global warming. Among agricultural activities, beef production stands out as one of the most consequential contributors to climate disruption. The question emerges as to whether some modes of beef production (e.g. “grass-fed” or pastured beef, as opposed to feedlot or dairy-associated beef) are more climate friendly than others. The different modes of beef production differ in the relative proportions of the major greenhouse gases — carbon dioxide, methane and nitrous oxide — that they emit.

In this talk, I analyze several modes of beef production, prevalent in North America and in Sweden, using simplified climate simulations and avoiding the use of aggregate metrics such as Global Warming Potentials. It is concluded that the best forms of pastured beef production (notably the Swedish Ranch System) can offer considerable advantages over feedlot systems, but that some forms of nominally grass-fed systems (especially those involving tropical deforestation) are worse than industrial feedlot systems by all metrics. However, even the most climate-friendly production systems, including feedlot systems employing carbon-neutral energy and fertilizer production, do not permit worldwide consumption at rates approaching the current North American levels, without making it virtually impossible to limit warming to 2C.