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Grassfed Beef and Greenhouse Gases Lawrence E. Widman, MD PhD
March 2019 (updated March 2020) The popular press asserts that the process of raising cattle for production of beef worsens anthropogenic global warming by increasing greenhouse gases. The short version of this article ("TL;DR" for the cognoscenti) is that the process of raising grassfed beef turns out to be so good for carbon sequestration that several organizations ( here (detail here) and here (detail here)) are starting up programs to pay farmers and ranchers for doing exactly what we are doing! Here is an article at CNN describing how this works. A scholarly review by Professor Richard Teague and colleagues here entitled "The role of ruminants in reducing agriculture’s carbon footprint in North America." appeared in the Journal of Soil and Water Converstation. March/April 2016; vol. 71, no. 2, pages 156-164, doi:10.2489/jswc.71.2.156, concluded "to ensure long-term sustainability and ecological resilience of agroecosystems, agricultural production should be guided by policies and regenerative management protocols that include ruminant grazing. Collectively, conservation agriculture supports ecologically healthy, resilient agroecosystems and simultaneously mitigates large quantities of anthropogenic GHG emissions." Other papers by Professor Teague include include Teague, Provenza, et al. 2013 and Teague, Provenza, Kreuter, Steffens, and Barnes 2013 discuss the advantages of multipaddock (high intensity) grazing and why prior studies may not have shown benefit from this method of carbon sequestration. A handy CO2 usage calculator at Indigo Ag lets you calculate your household's estimated CO2 production and then lets you make a contribution on the basis that each acre of grass can sequester about 2.5 tons of CO2 per year. Their suggested contribution is $20 per ton so they can pay farmers to do what we are doing. We have about 250 acres of grass and raise about 10 animals for sale each year (with a herd of about 60 animals). So if you buy two sides of our beef, you are supporting 25 acres of grassland. Indigo Ag estimates that the average household emits 50 tons of CO2 annually and needs to suppport 22 acres of regenerative agriculture to offset this. Therefore, you can offset your entire estimated output of CO2 (if you have an "average" household) just by buying two sides of our beef! There are two types of beef production. All cattle start by eating grass after they are weaned from their mother's milk. The difference is how they are raised to the weight at which they are slaughtered. The "feedlot" method involves putting many cattle into a small area and feeding them grains such as corn so that they gain weight rapidly. This method is very efficient, but requires that vast amounts of cropland be used to grow the grains, and this leads to release of greenhouse gases. The other method keeps the cattle on grass for their entire lives. This method takes longer, produces animals that weigh less and have less meat as a percentage of animal weight, but does not require grains. Careful studies show that when the most efficient method, "adaptive multipaddock" (AMP) grazing is used, the pastures sequester so much carbon that that the cattle produce less carbon dioxide than is put back into soil organic carbon. On balance, the AMP method sequesters even more carbon dioxide than the feedlot method produces. Regarding methane, Dr. Frank Mitloehner, UC-Davis, says science tells us with stable cow herds, we are not adding to climate warming. The reason is that methane is broken down into CO2 over about 10 years and then returns to the plants from which it came. If the number of cows burping methane is constant, the amount they burp is constant, and the level in the atmosphere is therefore constant (assuming stable rate of degradation back to CO2). In future versions of this article, I plan review the science of the greenhouse gases associated with raising beef, the new data that are available, and the conclusions that may be considered based on the new data. For now, consider the fact that farmers and ranchers are being paid, to benefit the environment, to do the kind of cattle raising that we are going because it sequesters so much carbon that it reduces overall green house gases. While this article is being fleshed out, here are some interesting pictures and graphs that illustrate the difference between the huge root systems of established pasture grasses and the less substantial ones of corn and annual crops. This is important because bigger root systems sequester more carbon from the atmosphere. |
