Format

Send to

Choose Destination
Proc Natl Acad Sci U S A. 2014 Aug 19;111(33):11996-2001. doi: 10.1073/pnas.1402183111. Epub 2014 Jul 21.

Land, irrigation water, greenhouse gas, and reactive nitrogen burdens of meat, eggs, and dairy production in the United States.

Author information

1
Physics Department, Bard College, Annandale-on-Hudson, NY 12504-5000; geshel@gmail.com ron.milo@weizmann.ac.il.
2
Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel; and.
3
Yale School of Forestry and Environmental Studies, New Haven, CT 06511.
4
Department of Plant Sciences, Weizmann Institute of Science, Rehovot 76100, Israel; and geshel@gmail.com ron.milo@weizmann.ac.il.

Abstract

Livestock production impacts air and water quality, ocean health, and greenhouse gas (GHG) emissions on regional to global scales and it is the largest use of land globally. Quantifying the environmental impacts of the various livestock categories, mostly arising from feed production, is thus a grand challenge of sustainability science. Here, we quantify land, irrigation water, and reactive nitrogen (Nr) impacts due to feed production, and recast published full life cycle GHG emission estimates, for each of the major animal-based categories in the US diet. Our calculations reveal that the environmental costs per consumed calorie of dairy, poultry, pork, and eggs are mutually comparable (to within a factor of 2), but strikingly lower than the impacts of beef. Beef production requires 28, 11, 5, and 6 times more land, irrigation water, GHG, and Nr, respectively, than the average of the other livestock categories. Preliminary analysis of three staple plant foods shows two- to sixfold lower land, GHG, and Nr requirements than those of the nonbeef animal-derived calories, whereas irrigation requirements are comparable. Our analysis is based on the best data currently available, but follow-up studies are necessary to improve parameter estimates and fill remaining knowledge gaps. Data imperfections notwithstanding, the key conclusion--that beef production demands about 1 order of magnitude more resources than alternative livestock categories--is robust under existing uncertainties. The study thus elucidates the multiple environmental benefits of potential, easy-to-implement dietary changes, and highlights the uniquely high resource demands of beef.

KEYWORDS:

food impact; foodprint; geophysics of agriculture; multimetric analysis

PMID:
25049416
PMCID:
PMC4143028
DOI:
10.1073/pnas.1402183111
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for HighWire Icon for PubMed Central
Loading ...
Support Center