What’s wrong with cow gas?

by Sally Colby

Reports of cow flatulence leading to global warming are rampant, with some sectors of the public demanding moves such as “Meatless Monday” to curb the problem.

U.C. Davis researcher, air quality specialist and professor Dr. Frank Mitloehner wants to set the record straight. When he learned that “Livestock’s Long Shadow,” a 2006 report by the Food and Agriculture Organization (FAO) of the U.N., claimed livestock have a major impact on the environment, Mitloehner was determined to find the truth.

Mitloehner spoke recently at the Dairy Summit held in Lancaster, PA, to explain his work debunking the FAO report stating that agriculture is a major contributor to greenhouse gasses (GHG) and climate change.

The role of livestock and global warming has received extensive media coverage, with frightening articles titled “Livestock causes 18 percent of all human-caused GHG,” “Livestock produces more GHG than the entire global transportation sector” and “Livestock occupies 70 percent of agricultural land.” The message is that if you must consume animal products, only eat animals from grazing systems and not conventional systems.

While Mitloehner was disturbed by these claims, he doesn’t deny climate change. “Climate change is happening,” he said, adding that heating and cooling is an ongoing process. “The question is not whether climate change happens, but whether human activity is the main driver – whether global warming is affected by human activity.”

Mitloehner explained how GHG affect Earth’s temperature. “The sun radiates down on Earth, and without GHG, solar beams would be reflected up and go back into space,” he said. “But because of the presence of these so-called GHG (carbon dioxide, methane and nitrous oxide) the radiant heat from the sun does not go back into space but is trapped by gas molecules.” Mitloehner further explained that CO2, methane and nitrous oxide differ in their ability to trap heat – a key factor in the explanation.

Methane is short-lived and breaks down after about 10 years. CO2 and nitrous oxide are long-lived and remain in the atmosphere for at least 1,000 years. “CO2 is cumulative and adds up over time,” said Mitloehner. “The same is true for nitrous oxide. Once that gas is in the atmosphere, it stays there for a long time.”

All methane emissions from fossil fuel production, agriculture, biomass burning, wetlands and other sources contribute 560 teragrams to the atmosphere every year. However, normal oxidation in the atmosphere “attacks” methane and converts it to CO2, destroying or sequestering 550 teragrams in the process. That process results in a minimal level of methane in the atmosphere.

Back to the U.N. FAO report “Livestock’s Long Shadow”: “This organization said in its executive summary that the livestock sector is a major player responsible for 18 percent of all greenhouse gasses, a greater share than transportation,” said Mitloehner. “When I read this for the first time, I was shocked.”

Here’s what matters. When Mitloehner and his team analyzed the report, they found critical mistakes. “They used what’s called the ‘life cycle assessment’ or LCA for livestock, meaning they looked at everything from soil emissions, crop emissions, emissions from feed and animals, emissions from manure,” said Mitloehner. “Then they added transportation like to a creamery or distribution center, restaurants, consumers and refrigeration. They went from the soil to putting food in our mouths – a cradle to grave assessment. They used that for livestock, but they didn’t do the same for transportation. For transportation they didn’t look into the production of trucks, cars, trains, planes, ships, harbors, airports, refining oil or transporting fuel. They only looked at the burning of gasoline to get from A to B. So with livestock they looked at everything but transportation they only looked at tailpipe emissions.”

When Mitloehner presented his findings at the American Chemical Society, an Associated Press reporter who was not a scientist interviewed him after his talk, then interviewed the FAO in Rome. “Then he wrote an AP wire news release that went to every news station in the world,” said Mitloehner. “After he hit the ‘send’ button, my life became a living hell. Everybody who had previously reported how bad livestock is to the environment now wanted to know why this U.C. Davis professor is the attacking force, and they wanted explanations.”

Mitloehner said the BBC said, “I must say he [Mitloehner] has a point. We’ve factored in everything for meat emissions and didn’t do the same thing with transportation.” In short, the authors of “Livestock’s Long Shadow” who said livestock were worse for the environment than the entire global transportation sector agreed with Mitloehner’s criticism. They retracted their statement and named Mitloehner the chair of a follow-up project called LEAP (Livestock Environmental Assessment and Performance) that established global gold standards to benchmark and quantify the impact of livestock on the environment. These guidelines are now available to the public on the LEAP web page.

The FAO’s major error in scientific method and subsequent reporting is a good example of what often happens when information is released and the general public believes it without seeking further clarification. However, Mitloehner said farmers also have a responsibility to gather accurate information and discuss issues with the public.

What does the EPA say in respect to livestock’s contribution to GHG? Mitloehner said the agency calculated approximate breakdowns for GHG contributors: 30 percent from power production, 26 percent from transportation, 21 percent from industry, 12 percent from commercial and residential and 9 percent from agriculture. He pointed out the agriculture sector represents all agriculture and is split between livestock and other production factors such as fuel and transportation for ag commodities. “According to the EPA, animal agriculture alone produces 3.9 percent of GHG,” he said. “So approximately 4 percent percent of GHG comes from livestock, versus about 26 percent from transportation.”

Farmers tend to be private people and don’t want to engage with the public at a level that Mitloehner said is increasingly important. Mitloehner was reluctant to engage on Twitter, but after using it, he realized how important it was. He also believes it’s important to let the public know that farmers have learned to use four important tools to reduce emissions: improved reproductive rates, an improved veterinary sector (healthcare and disease prevention), genetics and energy-dense diets.

“In 1950, we had 25 million dairy cows,” he said. “Today we have nine million. With a much smaller number, we produce 60 percent more milk, and we have shrunk the carbon footprint of a glass of milk by two-thirds.”

Mitloehner said believing in climate change (or not) isn’t as important as farmers’ awareness that their industry contributes to GHG. “If it matters to society, you should know what that contribution is,” he said. “You should also know that your industry has committed to 25 percent further reduction of GHG in the years to come, and that’s a lot. So own it, tell people we are aware of the challenge, we have quantified the challenge and we have made a commitment to further reduce. That’s a positive message you can share.”

Leave A Comment