Do Cows Cause Global Warming?

cows and climate change
Cows emit greenhouse gases. So does the fertilizer, deforested topsoil, and fuel that we use to irrigate and transport their feed.

“It takes 7 to 8 pounds of feed to produce a pound of beef and 5½ to 6 pounds of feed to produce a pound of pork,” says Robert Lawrence, professor of environmental health sciences, health policy, and international health at the Johns Hopkins Bloomberg School of Public Health in Baltimore.

In fact, most of U.S. farming is devoted to growing animal feed. “About 60 to 70 percent of soybeans and a slightly higher percentage of corn goes for animal feed rather than as feed for humans or other uses,” Lawrence notes. The water and fossil fuels needed to grow all that grain and the sheer number of animals consumed in the United States cause considerable damage:

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Water.

“It requires about 1,000 tons of water to produce a ton of grain,” explains Lawrence. “Worldwide, it’s estimated that 80 percent of groundwater from shallow and deep aquifers is used for agricultural purposes, and, increasingly, that purpose is irrigating crops for animal feed.” And it takes fuel to get that water.

“As we rely more and more on groundwater for irrigation in areas that aren’t getting enough natural rainfall, we need more and more energy to pump and distribute water to produce the feed.”

Methane.

“As ruminants, cattle digest the cellulose in feed in their rumens,” explains Lawrence. That produces methane gas that the cattle get rid of either by belching or passing wind. And methane is a potent greenhouse gas. “It has 23 times the heat-trapping capacity of carbon dioxide,” says Lawrence.

Nitrous oxide.

“Molecule for molecule, nitrous oxide has about 200 times the heat-trapping capacity of carbon dioxide,” says Lawrence. “Nitrous oxide comes from the intense application of nitrous fertilizers for the soy and corn being grown for animal feed.”

“But worse than that, the soil is exposed and often tilled to prepare it for seeding for pasture,” says Lawrence. “As soon as you begin to turn over soil to create pastureland, the organic material that’s trapped in the topsoil is exposed to the oxygen in the air and carbon dioxide is released.” And then comes fertilizer. “Particularly in tropical areas, the soil is lacking in nutrients, and when you start fertilizing that land, nitrous oxide is released.”

Solid waste.

“Big open cesspits can contain as much as three million gallons of urine and feces in a typical hog CAFO,” says Lawrence. (“CAFO” stands for concentrated animal feeding operation.) “A lot of anaerobic digestion goes on in the waste, which leads to methane production,” he adds. And using tarps to trap the methane “has been a big disappointment.”

It’s not just pigs. “The waste in big cattle feedlots can be properly composted, but it almost never is,” says Lawrence. “In a typical operation, the manure is just bulldozed into big mounds, so there’s a release of methane.”

Transportation.

“When animals in smaller numbers were grown on smaller farms, the feed was in the pasture or in the hay that was laid up for the winter,” says Lawrence. “Now we’ve moved animals into confinement, so we have to transport feed to them.” And that takes more fossil fuels.

Other reasons to save a cow:

8 Replies to “Do Cows Cause Global Warming?”

  1. What about grass fed beef? My understanding is that it is great for the cows health and our health. If cows are rotated through pastures and the pastures left alone inbetween visits by the cows the results are great: healthier cows, better quality meat, longer grass, moisture retention, carbon sequestration in the soil, nutrient recycling and less water usage (there are probably more benefits). Its available in the a lot of super markets; shouldn’t we be spreading the word? It also restores desertified land.

    Is my understanding incorrect? If not, shouldn’t this info be in the article? Thanks

    1. Karl,

      As you point out, it is really the human element that is creating these issues. The industrial farming methods we have developed to improve production are not environmentally sustainable.

      Thanks for the thoughtful addition.

  2. This is the second article I have read that seems to pin all our pollution problems on animal production or in particular cattle. I believe that scientifically there is a much larger polluter on earth called “mankind.” We still burn tons of coal in power plants and trillions of gallons of fossil fuels in inefficient automobiles. The article appears to be bias against the consumption of beef, chicken, and pork. While I do feel all mankind needs a diet rich in vegetables, fruits, grains, legumes, and yes some of that forbidden meat you speak of. What the article does not explain is; cattle production is down because our climate is becoming unconducive to sustaining cattle and other livestock due to severe drought in many areas of the US. You also don’t mention the economic trickle effects if we stop producing any livestock. Not only would we not have those food products available but most American Farmers would be out of work as would the many markets that supply them. There would be millions of items we would no longer have without livestock. I think your idea is far-fetched at best.

  3. Grass-fed cows actually produce 40 to 60 percent more methane gas than grain-fed cows and use more water and land, resulting in more greenhouse gases. Grass is harder to digest than grain and in part because grass-fed cattle are kept alive for a longer period of time, it results in more methane and respiratory emissions.

    There really is no responsible and sustainable way to farm animals for food. It’s an inefficient, broken, and archaic system that we no longer have a need for in our modern society. Not only would moving away from animal agriculture be better for the health of our planet, but also ourselves, and obviously the billions of animals bred, born, and raised every year for no other reason than to be cruelly slaughtered.

    Check out the documentary Cowspiracy for mind blowing information on the environmental impact of animal agriculture. http://www.cowspiracy.com

  4. lack of accuracy weakens article. why not request info from agricultural scientists (not a MD?)… cows and “deforested topsoil” – big problem in Brazil, not N. America. But – worldwide natural grasslands (not enough rainfall for tree’s) evolved as food source for grazing herbivores. European settlers destroyed the bison herds and late proceeded to destroy rich soils of the “great plains” by plowing and planting cereal grains, resulting in the dust storms of the ’30’s (and continuing distruction of natural ecological system. /Domesticated beef cows naturally have calves on pasture and raise calves to weights 500lb + (no grains fed). Cattle in feedlots require a large ration forage (hay, silage) component. Feed conversion (lb. feed/lb gain) include forage content – only a portion are cereal grains./ Soybeans processed to provide soybean oil (human use), only the byproduct “soybean meal.” (50%) fed to livestock, pigs, poultry./Wild and domestic (cattle, sheep…) herbivores evolved digestive system allowing microbial conversion of cellulose (not digested by omnivores) to energy sources we can utilize, and most important convert plant proteins (low quality – missing essential amino acids,eaa’s) to high quality proteins (milk, meat) necessary for proper human growth, pregnancy, lactation).
    Yes – too much beef consumed by many, grass-fed better, but let’s be accurate!
    Gene

  5. Take your education about beef production just a bit further than the worn out mantra above and read a little Alan Savory. You may actually find – as many are – that grass based protein production is the sustainable answer

  6. Karl, I suspect that grass fed cattle would be insufficient to meet the demand for their flesh. I’m not sure if I could be enticed to eat a “happy” cow, but the current reality is such that I am unlikely to ever have the opportunity.

  7. This post is the kind of material that can sink the effort to stop global warming, just as the tide is turning to regulate the by-far largest greenhouse gas, CO2. We need to stay on task and focus on stopping global warming now, not lose focus and bring in much less important topics like CH4 from cows!

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