Memo on CMU study: “Energy use, blue water footprint, and greenhouse gas emissions for current food consumption patterns and dietary recommendations in the US” (Tom et al., 2015)

The World Resources Institute (WRI) argues that a CMU study underestimated the environmental benefits of low-meat diets because it failed to account for land-use change, grouped beef with more efficient meats like pork, and modeled 'healthy' scenarios that actually increased total animal-based food intake. WRI asserts that shifting to realistic vegetarian diets can reduce per capita land use and greenhouse gas emissions by approximately half.

• The CMU study's 'Scenario 3', which followed USDA dietary recommendations, actually increased overall animal-based food consumption by 13 percent in terms of calories, leading to a 6 percent increase in GHG emissions, a 10 percent increase in water use, and a 38 percent increase in energy use relative to the current US diet.
• The CMU study underestimated environmental impacts by grouping beef, lamb, and pork into a single 'meat' category, ignoring that beef and lamb are far less efficient converters of feed and produce more methane than pork.
• The CMU study failed to examine land-use consequences or greenhouse gases resulting from land-use change, which WRI identifies as the most significant environmental benefit of reducing meat consumption.
• When the CMU Scenario 3 was analyzed using the GlobAgri model—which accounts for land use and separates beef from pork—it resulted in a 7.5 percent decrease in total GHG emissions and a 7.4 percent reduction in overall land use compared to the current US diet.
• The CMU study's methodology of averaging life-cycle assessments (LCAs) from different authors with varying methods and boundaries creates a high risk of inconsistent and misleading results.
• The press release for the CMU study contained inaccurate claims, including the assertion that vegetarian diets could be more harmful to the environment, despite the study not modeling any actual vegetarian diets.
• Animal-based products accounted for approximately 85-90 percent of the land use and GHG emissions of the average American diet in 2009, with beef alone accounting for nearly half of these impacts.
• Transitioning the average American to a realistic vegetarian diet would reduce per capita greenhouse gas emissions and land use by approximately 50 percent.

APA

Waite, R., & Searchinger, T. (2016). Memo on CMU study: “Energy use, blue water footprint, and greenhouse gas emissions for current food consumption patterns and dietary recommendations in the US” (Tom et al., 2015). World Resources Institute. https://wriorg.s3.amazonaws.com/s3fs-public/uploads/Memo_on_CMU_study.pdf

Chicago

Waite, Richard, and Tim Searchinger. Memo on CMU study: “Energy use, blue water footprint, and greenhouse gas emissions for current food consumption patterns and dietary recommendations in the US” (Tom et al., 2015). World Resources Institute, 2016. https://wriorg.s3.amazonaws.com/s3fs-public/uploads/Memo_on_CMU_study.pdf.

Wikipedia

{{cite report |last1=Waite |first1=Richard |last2=Searchinger |first2=Tim |title=Memo on CMU study: “Energy use, blue water footprint, and greenhouse gas emissions for current food consumption patterns and dietary recommendations in the US” (Tom et al., 2015) |publisher=World Resources Institute |date=17 May 2016 |url=https://wriorg.s3.amazonaws.com/s3fs-public/uploads/Memo_on_CMU_study.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{waite2016memo, author = {Waite, Richard and Searchinger, Tim}, title = {{Memo on CMU study: “Energy use, blue water footprint, and greenhouse gas emissions for current food consumption patterns and dietary recommendations in the US” (Tom et al., 2015)}}, institution = {World Resources Institute}, year = {2016}, month = may, url = {https://wriorg.s3.amazonaws.com/s3fs-public/uploads/Memo_on_CMU_study.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }