July 23, 2014
Beef production less sustainable than poultry, dairy, eggs or pork
Researchers estimate that livestock-based food production causes about one-fifth of all global greenhouse gas emissions and beef, in particular, releases five times more greenhouse gases compared to those other food sources.
In a new paper published in Proceedings of the National Academy of Sciences, researchers from Bard College, the Weizmann Institute of Science and Yale University broke down all of the various livestock categories in a standardised, whole-picture way to figure out each one's individual contribution to global warming. They focused on animals in the US food production system.
First, the researchers calculated the feed costs for each class of animal-beef, pork, chicken, laying hens and dairy cows. They did not include fish because data about resources used to raise those animals is limited, and fish only contributed about 2% of American's animal-based energy intake from 2000 to 2013.
They used data collected between 2000 to 2010 from the US Departments of Agriculture, Interior and Energy about land area, water and nitrogen fertiliser to determine the burden produced by feeding and raising all of those animals. Then, they standardised the data by calories contained in a given amount of milk, eggs, beef, pork or chicken.
The findings, while expected, are quite sobering. Pork, chicken, dairy and eggs are equivalent within a factor of two when it came to their environmental burdens, the authors determined. But beef requires far, far more resources than any of those other protein categories. The team calculated that beef requires 28 times more land, six times more fertiliser and 11 times more water compared to those other food sources. That adds up to about five times more greenhouse gas emissions.
The authors acknowledge that their calculations are not perfect, but say that they believe their results provide sound initial figures that consumers can use to help make decisions about their diet. "The key conclusion-that beef production demands about one order of magnitude more resources than alternative livestock categories-is robust under existing circumstances," the authors conclude.