Butter Is Toast

. . .  in an environmental showdown with margarine

My father-in-law was in the dairy business for over 40 years, and—as might be expected—he had nothing good to say about margarine. He called it a synthetic product of the chemical industry. Butter, of course, was natural and therefore better. I mischievously delighted in pointing out to him the purported health benefits of margarine over butter. If it had been available at the time, a recent life cycle assessment (LCA) comparing butter to margarine in the U.K., Germany, and France could have helped me make an even stronger case for margarine—this time from an environmental standpoint. (1) The comparative LCA found that margarine has a significantly lower environmental impact than butter in four important areas: global warming potential (GWP; i.e., carbon footprint), eutrophication potential, acidification potential, and land impact. Butter has a smaller environmental impact than margarine only with respect to its photochemical ozone creation potential, POCP. Margarine’s POCP is higher because hexane, which facilitates the formation of ozone in the lower atmosphere, is used in the vegetable oil–extraction process used to make margarine. Making margarine from vegetable oil is undeniably an industrial chemical process!

What makes the results of this comparative LCA so striking is that the impact differences between butter and margarine are so large. The carbon footprint of butter is over four times that of margarine. The large GWP for butter is attributable primarily to methane from dairy cows’ digestive systems, emissions from manure, and the production of feed for the cows. For the eutrophication and acidification impacts, the footprint of butter is at least twice that of margarine. Finally, land use for butter is about twice that of margarine because more land is needed to produce the feed for dairy cows than is needed to grow the crops for vegetable oil used to make margarine.

Overall, this is not one of those comparative LCAs where the differences between the two products are slight and the results might change depending on a small improvement here or there. The researchers had no hesitation in decisively concluding that margarine beats butter by most environmental measures.

—David Tyler

(1)  Nilsson, K. et al. 2010. International Journal of Life Cycle Assessment doi:10:1007/s11367-010-0220-3.

David Tyler is the Charles J. and M. Monteith Jacobs Professor of Chemistry at the University of Oregon.