My goal in writing this is not to simply disprove the naive notion that cow farts contribute significantly to global warming. I plan to show that large herbivores, far from being detrimental to the planet's ecology, actually play a critical role in improving soil, sequestering carbon and helping maintain a stable ecosystem.
First, a little about why meat farming in general, and beef in particular, has been given a bad name. The notion that cattle contribute to climate change due to methane produced in their digestive process is only part of the picture. That notion is easily disproven but first I'd like to point out that the problem is not the cattle themselves. Rather, the problem is the modern trend of industrial agriculture, including the use of CAFO's, which is unsustainable. Intensive rotation is often confused with overgrazing, which, like CAFO's, is unsustainable. The key difference is the time factor. That and the fact that intensive rotation (which mimics nature) can steadily increase carbon sequestration by building up root structure beneath the soil's surface. Overgrazing, on the other hand, kills the sod and much of the roots. Decomposition then releases the carbon into the air (mostly as carbon dioxide).
American bison are estimated to have numbered between 30 and 70 million at the time that white settlers first arrived in North America. Nobody was doing any accurate counting back then. Of course, these ruminants were free-ranging. They traveled in massive herds for protection from predators and kept on the move to find good grazing land. These herds impacted the grassland but only briefly, because they were on the move. The impact of these herds improved not only the quality of the native grasses, but also their ability to sequester carbon. This is because at least half of the carbon in a grassland is underground, in the root system of the native grasses. A lot of emphasis, today, is on planting trees as a remedy for climate change. This is a good thing. Properly managing pasture land is an even better thing. Why is this? Picture two areas of equal size. One is a well managed forest and the other a poorly managed grassland. Both are destroyed by fire. The carbon above ground is mostly released to the atmosphere in both cases. The grassland will recover the very next season. The forest begins a long process of recovery and regrowth and will take many years to catch up to the grassland's ability to sequester carbon.
Two of the best names in proving the importance of large herbivores in land management strategy are Allan Savory and Joel Salatin. Both are controversial. Both have excellent track records and a growing number of students. Links are provided for more on their work.
If you are still worried about the impact of bovine flatulence on climate change, ask yourself this: What happens to the grass that isn't eaten by cows? If it burns, it adds to atmospheric carbon. If it rots, it adds to atmospheric carbon. If it is sequestered underground for millions of years, then maybe one day a future civilization will dig it up as coal and burn that, in which case it will then add to atmospheric carbon. The point is, the cow is one more step in the carbon cycle (as are humans, in case you were wondering). None of these examples create carbon, they merely move it along to the next step in the cycle. Problems arise when billions of tons of sequestered carbon that were stored underground for millions of years get harvested and added to the carbon cycle in only a bit over a hundred years. It isn't the cow farts. Or at least that's my opinion.
Joel Salatin "Let's talk about Grass" - under 8 minutes
How to green the world's deserts and reverse climate change - Allan Savory - a bit over 22 minutes
1870 - Bison skulls pile (image)