FOREGOING meat and meat products is not the environmental panacea many would have us believe. And if taken to an extreme, it could also have harmful nutritional consequences.
That's the blunt message message from Dr Frank Mitloehner, a professor and air quality specialist in the Department of Animal Science at the University of California.
Speaking at the recent ONE: The Alltech Ideas Conference in Lexington, Kentucky, Dr Mitloehner debunked onging assertions that livestock were the largest source of greenhouse gases worldwide.
"Advocates urge the public to eat less meat to save the environment. Some activists have called for taxing meat to reduce consumption of it," Dr Mitloehner said.
"A key claim underlying these arguments holds that globally, meat production generates more greenhouse gases than the entire transportation sector. However, this claim is demonstrably wrong."
He said a 2009 analysis published by the US-based Worldwatch Institute asserted that 51pc of global green house gas emissions come from rearing and processing livestock.
However, he said according to the US Environmental Protection Agency, the largest sources of US GHG emissions in 2016 were electricity production (28pc of total emissions), transportation (28pc) and industry (22pc).
"All of agriculture accounted for a total of 9pc," Dr Mitloehner said.
"All of animal agriculture contributes less than half of this amount, representing 3.9pc of total US greenhouse gas emissions.
"That's very different from claiming livestock represents as much or more than transportation."
Dr Mitloehner said the misconception largely began in 2006 when the United Nations Food and Agriculture Organisation released its study Livestock's Long Shadow.
"It stated that livestock produced a staggering 18pc of the world's greenhouse gas emissions," Dr Mitloehner said.
"The agency drew a startling conclusion: Livestock was doing more to harm the climate than all modes of transportation combined."
However, Dr Mitloehner said for livestock, the FAO considered every factor associated with producing meat. This included emissions from fertiliser production, converting land from forests to pastures, growing feed, and direct emissions from animals (belching and manure) from birth to death.
"However, when they looked at transportation they only considered the exhaust emitted by finished cars, trucks, trains and planes."
Dr Mitloehner said to its credit, the FAO immediately owned up to its error in 2010.
"Unfortunately, the agency's initial claim that livestock was responsible for the lion's share of world greenhouse gas emissions had already received wide coverage" he said.
"To this day, we struggle to unring the bell."
In its most recent assessment report, the FAO estimated that livestock produces 14.5pc of global greenhouse gas emissions from human activities.
Dr Mitloehner said there was no comparable full life-cycle assessment for transportation.
"However, direct emissions from transportation versus livestock can be compared and amount to 14pc versus 5pc, respectively."
Dr Mitloehner also debunked claims that avoiding meat would make a significant difference to the climate.
"According to one recent study, even if Americans eliminated all animal protein from their diets, they would reduce US greenhouse gas emissions by only 2.6pc," he said.
"According to our research at the University of California, Davis, if the practice of Meatless Monday were to be adopted by all Americans, we'd see a reduction of only 0.5pc."
Dr Mitloehner said technological, genetic and management changes that have taken place in US agriculture during the past 70 years have made livestock production more efficient and less greenhouse gas-intensive.
FAO statistics show total direct greenhouse gas emissions from US livestock have declined 11.3 percent since 1961, while production of livestock meat has more than doubled.
Dr Mitloehner said there was no doubt removing animals from US agriculture would lower national greenhouse gas emissions to a small degree, but it would also make it harder to meet nutritional requirements.
"Many critics of animal agriculture are quick to point out that if farmers raised only plants, they could produce more pounds of food and more calories per person," he said. "
But humans also need many essential micro and macro-nutrients for good health."
Dr Mitloehner said not all plant parts are edible or desirable. Raising livestock is a way to add nutritional and economic value to plant agriculture.
As one example, the energy in plants that livestock consume is most often contained in cellulose, which is indigestible for humans and many other mammals. But cows, sheep and other ruminant animals can break cellulose down and release the solar energy contained in this vast resource, he said.
"According to the FAO, as much as 70 percent of all agricultural land globally is range land that can only be utilized as grazing land for ruminant livestock."
Dr Mitloehner said with the world population projected to reach 9.8 billion people by 2050, feeding people would raise immense challenges.
"Meat is more nutrient-dense per serving than vegetarian options, and ruminant animals largely thrive on feed that is not suitable for humans," he said.
"Raising livestock also offers much-needed income for small-scale farmers in developing nations. Worldwide, livestock provides a livelihood for 1 billion people."
Dr Mitloehner said climate change demanded urgent attention, and the livestock industry had a large overall environmental footprint that affected air, water and land. These, combined with a rapidly rising world population, meant there were many compelling reasons to continue to work for greater efficiencies in animal agriculture.
"I believe the place to start is with science-based facts," he said.
- Mark Phelps traveled to Lexington as a guest of Alltech Lienert.