Ruminants (mostly beef cattle) are blamed by environmental literature, the popular press and media and, increasingly, public for a significant portion of global warming. Extremists of this view believe that giving up beef will reduce the carbon footprint of mankind more than eliminating cars. Others believe that the sequestered carbon from pasture raised grass-fed beef can save the planet. The scientists tried to determine how much if any carbon is sequestered by grass-fed beef on net.
I should mention here that for decades what beef we eat is grass-fed. I started buying grass fed beef back in the 1990’s when I was doing environmental evaluations of farms, dairies and concentrated animal feed operations (CAFOs). I will not go into the details of that work that would shock most people; however, lets just say that my concerns for the animal welfare, mad cow disease, and environmental impact of CAFOs pushed me to buy my meat from the first sustainable farm I inspected. Today, in retirement, I continue to buy off the grid, sustainable, grass-fed beef from Polyface Farms here in Virginia.
Cattle that are grass-fed spend their entire lives grazing eating grass and forage that grows in the pasture. In addition, hay and silage which is just compacted grass are used to supplement in winter. Grass-fed beef require more land for pasturing as well as good management of the grazing to avoid over grazing the fields. This type of farm management protects our land and water resources. According to a study by Consumer Reports in 2015 found that conventional beef was twice as likely to be contaminated with these antibiotic resistant bacteria as more sustainably produced meat and three times more likely to be contaminated with the “superbug” bacteria as grass-fed organic meat.
Conventionally raised beef is where young cattle are shipped to feedlots where they are restricted in space and fed mostly corn and soybeans for several months to a year. They are also given antibiotics and other drugs to promote weight gain and prevent disease. In addition, they are sometimes feed other junk such as candy and feed that contains animal production waste. The animals in feedlots are crowded into pens; the average feedlot in the U.S. houses about 4,300 head of cattle, according to Food & Water Watch’s 2015 Factory Farm Nation Report.
Most academic studies have conclude that ruminant products, most commonly beef but also include goats, sheep, deer and others are the most emissions-intensive of all animal products, and within ruminant production systems, “conventionally raised” animals are the worst. However, that only measures greenhouse gas emission. Ruminant animals are actually rather miraculous and part of the planet’s ecology. Cattle and other ruminants can be raised on land unsuited to other food-producing purposes and on grain by-products from brewing and other food activities. In mixed a farming system the animals recycle nutrients and re-fertilize soils.
On the downside, ruminants emit large quantities of methane, use vast tracts of land, and are held responsible for a host of environmental ills, most notably deforestation and biodiversity loss, as well as the pollution of soils, air and water. Methane is a powerful greenhouse gas, but it has a shorter atmospheric life span than carbon dioxide (CO2). The effect of a given pulse of methane is temporary, unless replaced by another pulse. In contrast CO2’s warming effects are weak, but permanent. The next bit of CO2 emitted adds to the warming effects of all the CO2 emitted previously (except that absorbed by plants or other sequestered). So, because of their differing lifespans, a constant emission of methane from constantly replaced herd of cattle is therefore equivalent to one-off release of CO2.
The report , Grazed and Confused, found that the relationship between soil carbon sequestration and grazing intensity is complex. In soils that are not in equilibrium and where climate and other agro-ecological factors are right, light to moderate intensity grazing tends to promote sequestration of carbon overall. The scientists found some evidence to suggest that in some cases, grassland can store more carbon than forests. Thus, keeping ruminants on the land can achieve greater sequestration than removing them altogether and allowing woody vegetation to encroach.
However, the scientists state that on many lands, reversion to their natural wooded state would likely achieve higher levels of sequestration than would grazing although the loss of food from the grazing animals has to be compensated for elsewhere. The scientists also found that overgrazing damages soils, leads to soil carbon losses and undermines the organic matter in the soil and the soil overall health and fertility.
Overall the report found that grass-fed beef is not the magic bullet that will stop CO2 from building up in the atmosphere. However, as the scientists point out there are good reasons to build soil organic matter by pasturing livestock: soils rich in carbon foster soil fertility and health and a properly managed pasture with the livestock excluded from rivers and streams protects our waterways from contamination. The “conventional” livestock systems that operate today have caused an enormous amount environmental damage. Forests have been cleared, species driven to extinction, air and surface water polluted, and we have released vast quantities of greenhouse gases into the atmosphere.
Animal farming has also brought humanity huge benefits- It provides food that is highly nutrient dense, and very tasty. Farm animals can convert grass and silage that humans cannot eat into food that we can. When population densities were or still are sufficiently low and land abundant, livestock plays an important role in transferring nutrients from grasslands and onto cropland via their manure. The problem is there are over 7 billion people on earth none of whom want to be poorer or have less.
If you would like to watch the videos (which total more than an hour) here are the links: