The carbon footprint of meat and dairy proteins: A practical perspective to guide low carbon footprint dietary choices

摘要

Meat and dairy products in the food industry represent a significant portion of anthropogenic green house gas emissions. To meet the Intergovernmental Panel on Climate Change recommendations to limit global warming, these emissions should be reduced. Meat and dairy products are also responsible for the majority of our daily, vital, protein intake. Yet, meat and dairy products contain very different amounts of proteins, making it difficult in general to rationalize which protein source has the lowest carbon footprint. Here we present a practical and pedagogical review, comparing the carbon footprint of a variety of meat and dairy products with respect to their protein content. We investigate the carbon footprint of different dietary choices for several countries, by keeping the total number of meat and dairy proteins constant. Interestingly, we find that dairy-only diets are in general only a little less carbon intensive than current diets. However, 50% carbon footprint reduction may be obtained, throughout the world, with a "low CO2''-tailored diet including only small poultry, eggs and yogurt. Such a dietary pattern suggests easy to follow consumer guidelines for reduced carbon footprint. We report further on a number of consumer-oriented questions (local or imported? organic or not? cow or goat milk? hard or soft cheese?). Our methodology may be applied to broader questions, such as the carbon footprint of proteins in general (including fish and plant proteins). We hope our work will drive more studies focusing on consumer-oriented questions.