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March 31, 2010

Media Hype Masks Animal Agriculture's Climate Impact

Humane Society International

Numerous media outlets have recently published articles questioning the impact of animal agriculture on climate change, as well as the science behind human-induced climate change. These articles, based on misinterpretations of scientific reports and an over-exaggeration of minor errors, fail to discredit the vast body of scientific evidence pointing to human-induced climate change, animal agriculture's significant contribution to this problem, and our ability to mitigate those changes by making flexitarian, vegetarian, and vegan lifestyle choices. 

IPCC conclusions stand up to scrutiny

Minor errors in the Nobel-prize-winning Intergovernmental panel on Climate Change (IPCC)[1] Fourth Assessment Report: Climate Change 2007 (AR4)[2] have prompted an intense debate into the validity of the report, the continuing function of the IPCC, and even the validity of climate change science.[3]

In response, more than 250 scientists in the US have signed an open letter in support of the IPCC, stating, "None of the handful of mis-statements (out of hundreds and hundreds of unchallenged statements) remotely undermines the conclusion that 'warming of the climate system is unequivocal' and that most of the observed increase in global average temperatures since the mid-twentieth century is very likely due to observed increase in anthropogenic greenhouse gas concentrations."[4] A study published in March from the UK's Met Office reviewed studies published since the AR4 and concluded that the "only plausible explanation" for observed climate changes is human activity.[5]

How low can we go?

A report released by the World Wildlife Fund-UK (WWF-UK) in January confirmed the tremendous impact that animal agriculture has on the climate, and concluded that vegetarian diets can significantly mitigate this impact. However, the study warned that not all vegetarian foods are equal: diets overly dependent on imported and highly processed foods such as Quorn and tofu can also have a large carbon footprint.[6] This minor caveat was taken grossly out of context by numerous media outlets, which published headlines such as "Tofu can harm the environment more than meat, finds WWF study,"[7] and "How being vegetarian does more harm to the environment than eating meat."[8] These articles misconstrue the essential findings of this WWF study, "How Low Can We Go?," which lauds the benefits of eating lower on the food chain.

The report found, for example, that 58 percent of direct food production emissions come from animal products, and this figure would be even higher if it accounted for emissions from land use changes resulting from animal agriculture.[9] Further, the report found that switching to a vegetarian diet is the "most effective single measure" for reducing supply-chain emissions, with the potential to reduce emissions by 20 percent.[10] This increases to 38 percent when land use change emissions are included.[11]

Clearing the air?

The most recent media frenzy has come on the heels of a presentation on March 22nd by Frank Mitloehner, Ph.D., to the American Chemical Society.[12] Dr. Mitloehner's presentation was based on a 2009 paper, "Clearing the Air: Livestock's Contribution to Climate Change," [13] that was supported by a $26,000 research grant from the Beef Checkoff Program[14] and lacks a comparison of the carbon footprints of different diets.[15]

The paper takes issue with one statement from a 2006 Food and Agriculture Organization of the United Nations report, "Livestock's Long Shadow: Environmental Issues and Options (LLS)." [16] Specifically, the authors dispute the LLS conclusion that the livestock sector is responsible for a greater proportion of greenhouse gas emissions than transport.[17], [18] LLS authors used a more comprehensive methodology for calculating emissions from livestock than was used in calculating emissions from the transportation sector; however, this does not undermine the conclusion that a significant amount of global, human-induced greenhouse gas emissions are attributable to animal agriculture.[19]  As new methodologies for more accurately measuring GHG emissions are developed, more accurate estimates of animal agriculture's contribution to global GHG emissions will emerge.  However, it is clear that this sector is one of the largest contributors to climate change. 

Another argument in "Clearing the Air" is that the relative share of emissions from animal agriculture in developed countries is smaller than in developing countries because of much larger transportation and energy sectors.[20] "Clearing the Air" states that animal agriculture contributes less than 3 percent of US greenhouse gas emissions.[21] However, that calculation is based on EPA estimates of emissions from enteric fermentation and manure emissions, excluding emissions from other parts of the life cycle of animal products.[22] Furthermore, just based on these numbers, animal agriculture in the US was responsible for at least 197.7 million tones of carbon dioxide equivalent in 2007,[23] or more than the total human-induced emissions from Austria, Finland, and Denmark combined,[24] indicating that US animal agriculture is indeed a key contributor to global climate change.

So, while "Clearing the Air" has led to many misleading headlines, such as "Veggies are wrong and eating less meat will NOT save the planet,"[25] and "Go veggie to prevent warming? Bull,"[26] it fails to provide evidence to support these headlines. It also fails to discredit the LLS conclusion that "[t]he livestock sector emerges as one of the top two or three most significant contributors to the most serious environmental problems, at every scale from local to global."[27]

Incorporating environmentally sound and animal welfare-friendly practices into daily life, including adopting consumptive habits less reliant on meat, eggs, and dairy products, is necessary to slow the effects of climate change. For a more detailed explanation of animal agriculture's impact on climate change, please see An HSUS Report: The Impact of Animal Agriculture on Global Warming and Climate Change [PDF].


[1] Nobel Foundation. Nobel Prize Awarded Organizations. http://nobelprize.org/nobel_prizes/lists/organizations.html
Accessed March 24, 2010.

[2] Available at http://www.ipcc.ch/publications_and_data/publications_and_data_reports.htm#1.

[3] Eilperin J and Fahrenthold DA.  2010. Series of missteps by climate scientists threatens climate-change agenda. 
Washington Post, February 15, A01. http://www.washingtonpost.com/wp-dyn/content/article/2010/02/14/AR2010021404283.html.

[4] Open letter from U.S. scientists on the IPCC. March 10, 2010. http://www.openletterfromscientists.com/. Accessed March 24, 2010.

[5] Met Office.  2010. Climate change and human influence. Press release issued March 5. 
http://www.metoffice.gov.uk/corporate/pressoffice/2010/pr20100305.html. Accessed March 24, 2010.

[6] Audsley E, Brander M, Chatterton J, Murphy-Bokern D, Webster C, and Williams A.  2009. How low can we go? 
An assessment of greenhouse gas emissions from the UK food system and the scope to reduce them by 2050.  (WWF-UK, p. 6).  http://assets.wwf.org.uk/downloads/how_low_report_1.pdf.

[7] Webster B.  2010. Tofu can harm the environment more than meat, study finds. Times Online, February 12.  http://www.timesonline.co.uk/tol/news/environment/article7023809.ece.  Accessed March 24, 2010.

[8] Macrae F.  2010. How being vegetarian does more harm to the environment than eating meat. Mail Online. February 13.
http://www.dailymail.co.uk/health/article-1250532/Being-vegetarian-does-harm-environment-eating-meat.html. Accessed March 24, 2010.

[9] Audsley E, Brander M, Chatterton J, Murphy-Bokern D, Webster C, and Williams A.  2009.  How low can we go? 
An assessment of greenhouse gas emissions from the UK food system and the scope to reduce them by 2050.  (WWF-UK, pp. 4–5).  http://assets.wwf.org.uk/downloads/how_low_report_1.pdf.

[10] Id. at pp. 67–68.

[11] Id. at p. 68.

[12] American Chemical Society. 2010. Eating less meat and dairy products won't have major impact on global warming.
Press release issued March 22.  http://portal.acs.org:80/portal/acs/corg/content?_nfpb=true&_pageLabel=PP_ARTICLEMAIN&
node_id=222&content_id=CNBP_024345&use_sec=true&sec_url_var=region1&__uuid=9edcc5a4-e02a-4725-96fe-9e92d40319f1

Accessed March 24, 2010.

[13] Keefe LM.  2010. UC Davis prof refutes livestock-GHG connection. Meatingplace, March 23.

[14] UC Davis News Service.  2009.  Don't blame cows for climate change. Press release issued December 7.
http://www.news.ucdavis.edu/search/news_detail.lasso?id=9336.  Accessed March 24, 2010.

[15] Pitesky ME, Stackhouse KR, and Mitloehner FM.  2009. Clearing the air: livestock's contribution to climate change. Advances in Agronomy 103:1–40.

[16] Ibid.

[17] Id. at pp. 33–34.

[18] Steinfeld H, Gerber P, Wassenaar T, Castel V, Rosales M, and de Haan C.  2006. 
Livestock's long shadow: Environmental issues and options.  Food and Agriculture Organization of the United Nations.  p. xxi.
http://www.fao.org/docrep/010/a0701e/a0701e00.HTM.

[19] See id. at p. 113.

[20] Pitesky ME, Stackhouse KR, and Mitloehner FM.  2009.  Clearing the air: livestock's contribution to climate change. 
Advances in Agronomy 103:1–40, at pp. 33–34.

[21] Id. at p. 33.

[22] Id. at pp. 1, 4–5.

[23] U.S. Environmental Protection Agency.  2009.  Inventory of U.S. Greenhouse Gas Emissions and Sinks:1990–2007.  pp. 6-2, 6-8 table 6-6.  http://www.epa.gov/climatechange/emissions/downloads09/GHG2007entire_report-508.pdf.

[24] United Nations Framework Convention on Climate Change.  2009.  National greenhouse gas inventory data for the period 1990–2007. 
p. 17 table 5. (calculated from 2007 data).  http://unfccc.int/resource/docs/2009/sbi/eng/12.pdf

[25] Derbyshire D.  2010.  Veggies are wrong and eating less meat will NOT save the planet. Mail Online, March 22.
http://www.dailymail.co.uk/news/article-1259867/Veggies-wrong-eating-meat-NOT-save-planet.html. Accessed March 24, 2010.

[26] Maday J.  2010.  Go veggie to prevent global warming?  Bull.  Drovers,  March 23. 
http://www.drovers.com/news_editorial.asp?pgID=675&ed_id=7081&news_id=19665.  Accessed March 24, 2010.

[27] Steinfeld H, Gerber P, Wassenaar T, Castel V, Rosales M, and de Haan C.  2006. Livestock's long shadow: environmental issues and options. 
Food and Agriculture Organization of the United Nations.  p. xx.  http://www.fao.org/docrep/010/a0701e/a0701e00.HTM.