Grassfed Beef and Greenhouse Gases
Grassfed Beef and Greenhouse Gases

Lawrence E. Widman, MD PhD
March 2019

Table of Contents

Why are we talking about this? (Introduction)

The popular press asserts that the process of raising cattle for production of beef worsens anthropogenic global warming by increasing greenhouse gases. Dispassionate analysis shows that 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. In this article, I 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.
The audience for this review is the intelligent layman who wishes to understand the issues better. For this reader, citations to the primary and secondary literature are provided to facilitate further reading.
Constructive comments and questions may be directed to review-article at


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.

Jerry Glover, a soil scientist, shows off a perennial wheatgrass plant's long roots, which grow deeper than annual plants' roots, improving soil structure and reducing erosion. His mission is to encourage use of perennial crops by farmers to improve soil health, reduce erosion and polution by fertilizer runoff, and improve the efficiency of crop production.


Corn Has a Less Dense Root System

Fig. 85.--Mature root system of corn.