Carbon Footprint of U.S. Beef vs. Global Beef and Understanding the U.S. Beef Water Footprint
by Sara E. Place, Ph.D., Oklahoma State University
As a major contributor in food production, beef production provides a key service to our economy that must be maintained. However, production of beef and the associated feed crops required to produce beef also impact our environment. Due to the complexity of beef sustainability and the issues it encompasses, partners in the beef value chain often have complex or tough questions that require balanced, objective, science-based responses. Although most of the attention has been given to carbon footprint, there are other environmental impacts that must be considered, like water use. Overall, the U.S. beef industry’s dedication to improvement and innovation has lowered its environmental footprint while improving its social and economic contributions to communities across the country.
Before we can begin a discussion on the carbon and water footprint of U.S. beef production, we must understand what we are referring to when we use the term “footprint.” Carbon footprints are a measure that quantify the greenhouse gas emissions resulting from production and are expressed as carbon dioxide (CO2) equivalent emissions to account for the different greenhouse gases’ potential to trap heat in the earth’s atmosphere. For beef production, a carbon footprint refers to CO2 equivalent emissions per unit of beef produced. Water use estimates, or water footprints are defined as the amount of water used per unit of beef produced.
Comparing the U.S. beef industry’s carbon footprint to other nations is challenging for two main reasons: 1) the methodologies used in different published studies to calculate carbon footprints within and across nations vary in ways that can influence their estimated carbon footprint, and 2) the efficiency of practices in how beef cattle are raised varies greatly across countries (i.e. productive use of resources to maximize the total amount of beef produced), and efficiency is a key driver of beef’s carbon footprint. To overcome these challenges, one can examine the results from individual studies that use the same methodology to estimate CO2 equivalent emissions across the wide range of beef production systems found in the world.
As with measuring the U.S. beef industry’s carbon footprint, measuring its water footprint also presents a challenge. When looking for an answer to the question, “How much water is required to produce beef?” one may find a variety of answers. Water use estimates, or water footprints, are available in the scientific literature and indicate that water footprints range from 317 (Scanlon et al., 2012) up to 23,965 (Pimentel et al., 1997) gallons per pound of boneless beef. Why is the range so large? The range in estimates is mostly due to the methodology used by researchers. For example, some have counted all precipitation that falls toward the total water use of beef while others have left out precipitation altogether. However, irrigation water use is always considered toward the total water use of beef.
In two recent analyses of global livestock systems (Opio et al., 2013; Herrero et al., 2013), North American beef production systems (including the U.S.) were found to have some of the lowest carbon footprints. As seen in Figure 1, when CO2 equivalent emissions are expressed per kg of protein, the U.S. and other developed nations have lower carbon footprints (10 to 50 times lower) as compared to many nations in sub-Saharan Africa and the Indian subcontinent (Herrero et al., 2013).
The lower CO2 equivalent emissions per kg of protein for beef production systems in the developed world are driven by higher-quality (more digestible) feeds, lower impacts of climate stress (heat) on animals, improved animal genetics, advancements in reproductive performance, and the reduced time required for an animal to reach its slaughter weight as compared to regions with higher carbon footprints (Opio et al., 2013; Herrero et al., 2013). Combined, all of the above mentioned factors drive improvements in the efficiency of beef production while decreasing the use of natural resources and production of environmental emissions per unit of beef produced. Furthermore, it is these factors that are responsible for reducing the U.S. carbon footprint of beef by an estimated 9-16 percent from the 1970’s to the present day (Capper, J.L. 2011; Rotz et al., 2013). Using management techniques and technologies developed through scientific research is key to achieving improvements in beef production efficiency and further reducing beef’s carbon footprint.
Figure 1. Greenhouse gas emissions from beef production expressed as kg of CO2 equivalents per gram of protein
Herrero et al., 2013 PNAS 110: 20888-20893
Regardless of methodology, the production of feed for cattle is the single largest source of water consumption in the beef value chain (~95 percent of the water used to produce a pound of beef). The relative importance of this water use is highly dependent on location, because unlike greenhouse gas emissions, water use and access is a highly regionalized environmental issue, thus one must be cautious about generalizing water footprints for beef or any other product on a national scale.
Beef cattle can, however, play a role in water conservation. For example, in the High Plains of Texas, an integrated beef cattle and crop system used 23 percent less irrigation water than a system with crops only (Allen et al., 2005). The increase in irrigation water use efficiency was mostly due to the incorporation of perennial warm season grass into the farming system (Allen et al., 2005). Perennial grasses would not be as valuable to sustainable farming systems without cattle that have the ability to digest such grasses because humans cannot directly consume and digest grass.
Though the U.S. beef industry reduced its water use by 3 percent from 2005 to 2011 (Battagliese et al., 2013), many opportunities exist to further improve water use across the beef value chain (Figure 2). One area that is often overlooked and is important to all aspects of sustainability, not just water use, is reducing food waste. Reducing food waste can help reduce the water footprint of beef and all other foods.
Figure 2. Examples of opportunities to reduce the water footprint of beef throughout the beef value chain.*
*Photos by USDA, USDA NRCS and USDA ARS
The U.S. beef industry has one of the lowest carbon footprints in the world due to cattle genetics, the quality of cattle feeds, animal management techniques and the use of technology. A number of studies have determined the carbon footprint of beef production, with most values ranging from 10 to 15 pound CO2e/lb BW (Rotz et al., 2013). The estimated water required for beef production greatly depends on the methodology used in scientific calculations, especially when considering whether or not precipitation water is included in water footprints. U.S. specific estimates put beef water use at 317 (Capper, J.L. 2011), 441 (Becket and Oltjen, 1993) and 808 (Rotz et al., 2013) gallons per pound of boneless beef when precipitation water is not accounted for in calculations.
As with all food production, reducing food waste and efficiently utilizing irrigation water, particularly in water-stressed regions, as well as continuing to improve production efficiency is an important aspect of beef sustainability. The production of beef results in emissions of greenhouse gases and requires consumptive water use; therefore, it is crucial that U.S. beef’s carbon and water footprint continue to be evaluated for opportunities to minimize their impact in order to increase overall beef value chain sustainability.
- How does the carbon footprint of U.S. beef compare to global beef?
- Does Beef Really Use That Much Water?
- Allen, V. G., C. P. Brown, R. Kellison, E. Segarra, T. Wheeler, P. A. Dotray, J. C. Conkwright, C. J. Green, and V. Acosta-Martinez. 2005. Integrating cotton and beef production to reduce water withdrawal from the Ogallala aquifer in the Southern High Plains. J. Agron. 97: 556-567.
- Battagliese, T., J. Andrade, I. Schulze, B. Uhlman, C. Barcan. 2013. More sustainable beef optimization project: Phase 1 final report. BASF Corporation. Florham Park, NJ.
- Beckett, J.L. and J.W. Oltjen. 1993. Estimation of the water requirement for beef production in the United States. J. Anim. Sci. 71:818-826.
- Capper, J.L. 2011. The environmental impact of beef production in the United States: 1977 compared with 2007. J. Anim. Sci. 89:4249-4261.
- Herrero, M., P. Havlík, H. Valin, A. Notenbaert, M.C. Rufino, P. K. Thornton, M. Blümmel, F. Weiss, D. Grace, and M. Obersteiner. 2013. Biomass use, production, feed efficiencies, and greenhouse gas emissions from global livestock systems. Proc. Natl. Acad. Sci. 110: 20888-20893.
- Opio, C., P. Gerber, A. Mottet, A. Falcucci, G. Tempio, M. MacLeod, T. Vellinga, B. Henderson, and H. Steinfeld. 2013. Greenhouse gas emissions from ruminant supply chains – A global life cycle assessment. Food and Agriculture Organization of the United Nations (FAO), Rome.
- Pimentel, D. J. Houser, E. Preiss, O. White, H. Fang, L. Mesnick, T. Barsky, S. Tariche, J. Schreck, and S. Alpert. 1997. Water resources: Agriculture, the environment, and society. BioSci. 47: 97-106.
- Rotz, C.A., B.J. Isenberg, K.R. Stackhouse-Lawson, and E.J. Pollak. 2013. A simulation-based approach for evaluating and comparing the environmental footprints of beef production systems. J. Anim. Sci. 91(11):5427-5437.
- Scanlon, B.R., C. C. Faunt, L. Longuevergne, R. C. Reedy, W. M. Alley, V.L. McGuire, and P.B. McMahon. 2012. Groundwater depletion and sustainability of irrigation in the US High Plains and Central Valley. Proc. Natl. Aca. Sci. 109: 9320-9325.
Tags: Beef Issues Quarterly, Fall 2015, Issues Updates
September 22, 2015