From 1985 to 1992, ABC aired a detective show, “MacGyver,” which followed the adventures of Angus MacGyver, a secret agent armed with remarkable scientific skills, solving problems in the field using any materials at hand.

The episode I liked best featured MacGyver hunkered down in a swamp, trying to outwit some criminals. He pointed out a bamboo shoot to his associate, asking him to saw about three feet of its stalk. (He just happened to have a small saw.) He then demonstrated how to shove this improvised pipe into the swampy mud. He explained that the methane (natural gas, lighter than air) would escape the muddy bog via the woody tube. With a lighter (which he also happened to have), he torched the natural gas quite explosively. Somehow, they collected enough methane to blow up the equipment needed by the bad guys to carry out their dastardly deed.

Fast forward to 2019, when UC-Davis published a study to help a national fast food chain find ways to reduce methane emissions produced by beef cattle destined to become hamburgers. Researchers determined that 60% of methane was emitted from their mouths and noses; 40% was released from the other end. These scientists determined that adding 100 grams of dried lemongrass leaflets to each cow’s daily ration reduced methane by 33% during the experiment. What goes on inside the cow’s rumen is fairly similar to what takes place in a stagnant swamp.

The swamp gas harnessed by MacGyver, aka marsh gas or bog gas, consists primarily of methane, smaller amounts of hydrogen sulfide and carbon dioxide. It’s produced naturally within many marshes and swamps. Importantly, it’s considered by atmospheric scientists to pose serious greenhouse gas (GHG) threats.

Bovine methane emissions were also addressed at the University of Vermont. Researchers determined that with the right pasture, and a winter feed that simulates pasture, some Vermont farmers saw an 18% methane emission reduction in their cattle. Achieved nationwide, that kind of GHG mitigation could achieve almost three-quarters of the goal of reducing dairy industry GHGs by 25% by 2030 – a goal set by USDA and the Innovation Center for U.S. Dairy.

Another benefit is that milk from pastured cows is commonly several times richer in omega-3 fatty acids than milk from dairy cattle in feedlots. Scientists working for France-based group Danone (makers of Dannon Yogurt) found that when cattle were on pasture in spring, they were healthier. When they added omega-3-rich grasses to their feed year-round, the cows not only released less methane, they also produced about 10% more milk.

Ruminants produce GHGs, particularly methane. But W. Richard Teague, Ph.D., a grasslands research ecologist at Texas A&M, and coworkers proposed that with appropriate regenerative crop and grazing management, ruminants reduce overall GHG emissions. Properly managed, these livestock can increase soil carbon sequestration, reducing environmental damage. These scientists tested their hypotheses by “examining biophysical impacts and the magnitude of all GHG emissions from pastoral-based agro-ecosystems.”

Teague’s crew showed that globally, GHG emissions from domestic animals represent 11.6% of total anthropogenic (human-associated) emissions. Here the predominant GHG was methane (CH4), the main gaseous byproduct of ruminant belching. This figure compares to cropping and soil-associated emissions contributing 13.7% of the grand total attributable to humankind. The primary source of this latter breakdown is soil erosion, which in the U.S. is estimated to be 1.9 gigatons of soil annually. (A gigaton is one billion tons.)

Permanent forage plant cover significantly reduces soil erosion, and ruminants consuming only grazed forages, under appropriate management, sequester more carbon than what they emit. Incorporating forages and ruminants into regeneratively managed agro-ecosystems elevates soil organic carbon. This type of pasture management counters soil ecological issues caused by tillage, chemical fertilizers and biocides. Keeping carbon in soil enhances biodiversity and wildlife habitat. Teague’s team concluded, “In order to ensure long-term sustainability and ecological resilience of agro-ecosystems, agricultural production should be guided by policies and regenerative management protocols that include ruminant grazing. Collectively, conservation agriculture supports ecologically healthy and resilient agro-ecosystems, simultaneously mitigating large quantities of anthropogenic GHG emissions.”

Intensified agriculture increases surface water runoff and soil erosion. Under the anaerobic conditions of anoxic (little or no oxygen) sediment deposits, emissions of CH4, nitrous oxide (N2O) and ammonia from water bodies collectively almost equals the quantity of emissions from cattle. The N2O and CH4 emissions generated by the disturbance of continued tillage, plus the erosion of soil organic carbon (SOC) from clay and silt clay loam soils, have been one of the primary sources of GHG emissions.

In addition to the negative impact of the increasingly industrialized crop production, there has been considerable degradation of rangelands, which comprise approximately 40% of Earth’s tillable land mass. With rangeland’s ecosystems comprising roughly 25% of potential carbon sequestration in our planet’s soils, their degradation elevates GHGs, reduces ecosystem services and increases desertification.

Many rangelands have been subjected to increasingly intense livestock grazing. Such mismanagement has depleted root biomass and carbohydrate reserves in selectively grazed plants plus reduced above-ground biomass productivity. Other negative effects of poor grazing management include impoverished herbaceous plant communities, more bare ground, lower SOC reserves and increased soil erosion and compaction.

Collectively, these changes contribute to lower surface water infiltration, increased runoff, downstream flooding and reduced water quality. As with tillage agriculture, the sediments from eroded grassland soils also emit GHG when organic matter in sediments enters anaerobic waterways. As the health of the land declines, so does the health of livestock and the people dependent on livestock.

What I find strangely ironic is that some learned faculty members preach that the use of synthetic growth hormones will increase milk production per cow, thus reducing the number of animals needed to meet the nation’s milk requirement. A smaller national dairy herd does mean less methane being belched and otherwise emitted. What these scientists, however, conveniently ignore is that most of these dairy mega-farms employ anaerobic manure systems. These, arguably, are some of the biggest GHG generators on the planet, seriously eclipsing MacGyver’s methane-emitting mud.