CALF_News_August_September_2021

22 CALF News • August | September 2021 • www.calfnews.net C an beef cattle production in the United States be a solu- tion to global warming? Yes, says Frank Mitloehner, Ph.D., air quality specialist at the University of California Davis. How he arrived at that conclusion involves a combination of chemistry and common sense. First, the Chemistry There are three main chemical com- pounds that cause the atmosphere to warm. They are methane, carbon dioxide (CO2) and nitrous oxide (NO3). For beef producers, methane is the main concern because cattle produce enteric methane as a normal course of digesting roughages. Or more accurately, methane- producing microorganisms in the rumen produce the gas that cattle and other ruminants exhale. Manure and urine are also methane sources. In fact, methane is our No. 1 environ- mental issue, Mitloehner told members of the Colorado Livestock Association (CLA) at the group’s recent annual convention. While the data around global methane production have been misrepresented to show cattle as the No. 1 culprit in methane production, that’s not the only reason methane is a concern and an opportunity for beef producers. There are several reasons the data aren’t being reported correctly and are being misrepresented. The first is that methane production from cattle is often reported on a global scale. That misrepresents the amount of methane produced by cattle in the United States, Mitloehner said. “It’s estimated that 70 percent to 80 percent of all greenhouse gases from livestock globally stem from developing countries,” he said, adding that methane is the main greenhouse gas associated with livestock production. The reason for the imbalance is that cattle in developing countries are gener- ally on a much poorer diet nutrition- ally than cattle in developed countries, especially the United States. The lower the nutritional quality and the higher the roughage, the more methane cattle exhale, he said. Then there’s this: The methane emitted by cattle is recycled every 10 years. In the case of methane, radicals are the friends of beef producers. That’s because radicals in the atmosphere destroy methane. Globally, 558 teragrams of methane are produced, “and that’s where the media normally stops reporting,” he said. However, 548 teragrams are destroyed as a normal course of the carbon cycle, meaning methane production is essen- tially a zero sum process. Carbon dioxide stays in the atmo- sphere for 1,000 years, he said, and nitrous oxide hangs around for 100 years. “The lion’s share of greenhouse gases emitted by the United States are associated with the production and consumption of fossil fuels – oil, coal and gas,” he said. In short, we’re extract- ing carbon that has been stored under- ground, burning it and sending it back into the atmosphere. That means the CO2 is additive.When a soccer mom drives the kids to soccer practice, the gasoline she burns produces carbon dioxide, which goes into the atmo- sphere.When they go to the game, more CO2 is produced. But the CO2 from the earlier trip is still hanging around. It doesn’t go away. Methane produced by ruminants does go away. Then there’s carbon sequestration, which is nothing more than plants performing their daily photosynthe- sis workout. This carbon, taken from atmospheric CO2, remains in the soil as food for the soil microorganisms. That is, until the soil is disturbed, by tillage for instance. Then the carbon is released back into the atmosphere. Thus, the total greenhouse gas foot- print for U.S. agriculture is around 10 percent. Livestock account for 3 percent, Mitloehner said. Now the Common Sense For 20-plus years, a mathematical process called GWP100 has been used to estimate the amount of greenhouse Cattle and Climate Change The Rhetoric Around Cattle's Contribution to Global Warming Is Changing By Burt Rutherford Contributing Editor COVER STORY