The impact of livestock on climate change is a topic of interest and concern for ranchers. Research over the past several years has developed ways to mitigate the impacts.

According to a paper released this year by UC Davis John Muir Institute of the Environment, there are opportunities for farmers to focus on mitigation of greenhouse gases. In particular, agricultural ‘waste’ products could be used to increase renewable energy. Specifically, the integration of methane digesters could play a significant role in renewable energy production from carbon-based agricultural ‘waste’ material.

Among the contributors to the paper is Frank Mitloehner, U.C. Davis Professor of Animal Science and Air Quality Extension Specialist.

Livermore rancher Darrel Sweet said of climate change, “Local cattlemen care about their impact on the environment, and there is reputable, scientific information to share with the public.”

Sweet, the former president of the California Cattlemen’s Association, stated, “We want our consumers and legislators to have accurate and trustworthy information on which to base their decisions."

Sheila Barry, the U.C. Cooperative Extension Natural Resources Advisor for Alameda County, has co-authored an article using comments by Mitloehner. She and co-author Theresa Becchetti, a Farm Adviser with the U.C. Cooperative Extension from San Joaquin County, wrote "Livestock's Impact on Greenhouse Gasses and California's Rangelands". The article uses data from, “Livestock’s Long Shadow”, a 2006 United Nations Report released by the Food and Agriculture Organization (FAO). The FAO revised its estimates of agriculture emissions in 2013, taking into consideration the comments of scientists such as Mitloehner, who served as Chairman of the FAO’s Partnership Project for the Benchmarking of Environmental Impacts of the Global Livestock Supply Chains from 2012-2015.

The Barry and Becchetti article includes an explanation of the source of pollution, as well as efforts to lessen them: "The emissions from cows is often mistakenly called ‘cow farts.’ However, methane emissions from cows come primarily from “belching”. Ruminant animals including cattle, sheep, goats, deer, bison, elk etc. have billions of microbes in their rumens, which operate like a large fermentation vat in their digestive system.

Data reported in the 2016 California Statewide Greenhouse Gas Inventory indicate, “ 8% of the state’s greenhouse gas (GHG) emissions come from agriculture (livestock and crops); residential and commercial activities generate 12%, while 80% of emissions are from transportation, electricity, and industry, with 1% unidentified. Of the 8% from state agriculture, half is from all of livestock production. Other researchers (White and Hall 2017) have calculated that even if everyone living in the U.S. became vegan (consuming no meat, no dairy, no eggs, no fish), we would reduce our total GHG emissions by only 2.6%. Dr. Mitloehner points out that the greenhouse emissions saved by one person eating a vegan diet for one year is equivalent to cancelling a one-way flight from San Francisco to London.

"Meat producers are very efficient in the US and California, and have continually made improvements in pounds of production per animal, improved breeding, improved health, etc. The US produces more beef with less GHG emissions than any other country.

"The impact of livestock production on greenhouse emissions is a simplistic view of a much more complex environmental picture. Livestock production, especially in California, provides a vital role in many ecosystem services. Cattle grazing on rangelands can help sequester carbon on grazed lands. Manure is often used in organic farming as the main fertilizer. Livestock plays a vital role in upcycling by-products from other ag sectors, such as almond hulls, tomato pumice, rice bran, cottonseed and distiller’s grain.

"Cattle grazing, the number one land use in California, reduces fire fuel loads by consuming grass, can minimize greenhouse gas emissions from catastrophic wildfires, and supports habitat for many of California’s threatened and endangered species (Bartolome et al. 2014, Germano et al. 2012, Marty 2005, Weiss 1999). The research shows that it is too simplistic to suggest that reducing meat consumption is a climate smart strategy."

Recent postings online point out efforts to mitigate the impacts of the methane produced by livestock.

A 2013 report, “Tackling climate change through livestock”, from the FAO noted that an important emitter of greenhouse gases (GHG), the livestock sector, also has a large potential to reduce its emissions.

"Beef and cattle milk production account for the majority of emissions, respectively contributing 41 and 19 percent of the sector’s emissions, while pig meat and poultry meat, and eggs contribute respectively 9 percent and 8 percent to the sector's emissions.

"The main sources of emissions are: feed production and processing (45 percent of the total – with 9 percent attributable to the expansion of pasture and feed crops into forests), enteric fermentation from ruminants (39 percent), and manure decomposition (10 percent). The remainder is attributable to the processing and transportation of animal products.

"Possible interventions to reduce emissions are mainly based on technologies and practices that improve production efficiency at animal and herd levels. They include better feeding practices, animal husbandry and health management.

"Manure management practices that ensure the recovery and recycling of nutrients and energy contained in manure, and energy savings and recycling along supply chains, are further mitigation options."

“Methane pollution causes one quarter of the global warming that we’re experiencing right now,” says Fred Krupp of the Environmental Defense Fund in his TED talk.

He described efforts to deal with the production of methane. “Feeding cows seaweed, onions or probiotics could cut their methane emissions. A Texas lab is experimenting with giving cows probiotics in their feed and water, which has led to a 50 percent reduction in methane emissions. In California, feeding cows a mixture of dried seaweed and molasses has shown promising results, while in Spain, giving them small amounts of the chemical compound in onions has done the same. In India, a national program is optimizing cows’ diets to reduce methane emissions and help them produce more milk. "

Krupp mentions the use of manure in environmentally friendly ways. "All over the world, farmers are investing in methane digester systems to capture the methane that builds up in their manure tanks. (The manure is later used for fertilizer). This methane can be used to fuel their operations, or be sold to power companies." Watch Krupp’s TED talk, “Let’s Launch a Satellite to Track a Threatening Greenhouse Gas,” at www.ideas.ted.com.