A week ago, Proceedings of the National Academy of Sciences published “Land, irrigation, water, greenhouse gas, and reactive nitrogen burdens of meat, eggs, and dairy production in the United States”.

The authors, a physicist from Bard College in New York, a physicist and a graduate student from Weizmann Institute of Science in Israel, and a Yale graduate student with a master’s degree in political science, looked at lifecycle assessments (LCA’s) for livestock. An LCA tries to estimate environmental impacts by looking at the inputs used (e.g. energy, feed, fertilizer, water, etc.) and outputs generated (e.g. greenhouse gases, smog, manure, fertilizer runoff, etc.) when meat, milk or eggs are produced, processed, transported, distributed, consumed, and recycled.

The authors of this study noted that regional variations in production systems and environments are important: “the results of an LCA conducted in Iowa, for example, are unlikely to represent Vermont or Colorado”. A key challenge, they said, “is Continue reading →