INDIANAPOLIS, Ind. — Since the 2006 United Nations (UN) report on Livestock’s Long Shadow by its Food and Agriculture Organization (FAO), livestock producers have reaped a grim outlook from environmentalists around the world.

The report stated livestock is responsible for 18 percent of greenhouse gas (GHG) emissions measured in carbon dioxide worldwide, more than emissions from all transportation systems. The Worldwatch Institute claims the number is closer to 51 percent.

The information permeated culture. In Sweden, customers can order sandwiches based on the carbon footprint it created during production.

Enter Frank Mitloehner, PhD, associate professor and air quality specialist with the Department of Animal Science at the University of California-Davis. His team studies the claims made by such reports, to prove them true or false. “It’s my job to be the watchdog,” Mitloehner said.

His group’s research was instrumental in refuting the report and clearing the air for the media last year, affirming that consumption of meat and dairy products is not linked to global warming. But the FAO report’s “long shadow” formed a cloud over the U.S. livestock industry.

The world’s livestock by far is concentrated in China and India, and rather than the 18 percent GHG with which those areas contend, the United States has only 3.4. Still, the fear factor is played on the American public, Mitloehner said.

“We have 3.4 percent GHG in the U.S., but we get confronted with 18 all the time,” Mitloehner said. “So the liberal groups continue to push ‘Meatless Mondays.’ Those groups are usually absent at our international conferences, and I wonder why that is.”

He said the worldwide percentage also includes land use issues in developing countries such as deforestation, which inflates the number by as much as one- third. Livestock production in developed countries is a model for the rest of the world because of its efficiencies.

Livestock production is a lifecycle, in which soil produces a crop to feed the herd and the herd produces manure to fertilize the soil. The comparison to transportation is not appropriate, he said.

“When livestock production is compared to transportation, which is not a lifecycle, it is a pure ‘apples to oranges’ comparison,” Mitloehner opined. “Livestock in developed countries has relatively small GHG contribution dwarfed by large transportation, energy and industry.”

In developing countries livestock can be the dominant contributor to GHG due to deforestation and to their relatively smaller transportation and energy sectors. Mitloehner said efficiency in the American livestock production system actually lowers GHG.

In the dairy industry, for example, dairy cow numbers have dropped since World War II from 25 million to 9 million. But milk production nationally has increased 60 percent because of efficient practices of dairy farmers. “So the carbon footprint of a glass of milk today is two-thirds smaller than it was 70 years ago,” he said.

Since Mitloehner’s response to the FAO report, the UN took a second look at the statistics in 2011. Its follow-up study looked at the dairy industry and agreed that the more milk produced per cow in efficient operations, the less methane and waste is produced.

In “shrinking the shadow,” Mitloehner said, the key is intensification, technological change and a realignment of incentives for developing countries.