A sequel to "Livestock's Long Shadow," scientific opinion

Dec 27, 2013

New international opinion points finger at livestock again in climate change


Anyone in the world of livestock production should be familiar with the United Nations’ 2006 report, “Livestock’s Long Shadow.” The report’s shocking statistics that greenhouse gas emissions from livestock outstrip those of the entire transportation sector and account for roughly 18 percent of all greenhouse gas emissions have been widely quoted in the U.S.

And also thoroughly debunked, but more on that later.

A new opinion piece, running in a professional journal on climate change, is reigniting the heated conversation over climate change and again leveling hefty amounts of blame on livestock production. The opinion piece—“Ruminants, Climate Change, and Climate Policy,” running in the most recent issue of Nature Climate Change—comes from an international research team and posits that not enough attention has been paid to non-carbon dioxide (CO 2 ) greenhouse gasses such as methane.

“Because the Earth’s climate may be near a tipping point to major climate change, multiple approaches are needed for mitigation,” said William Ripple, a professor in the College of Forestry at Oregon State University and one of the several authors of the commentary.

“We clearly need to reduce the burning of fossil fuels to cut CO 2 emissions. But that addresses only part of the problem. We also need to reduce non- CO 2 greenhouse gases to lessen the likelihood of us crossing this climatic threshold.”

The commentary— which is described as an “opinion commentary” in the official Oregon State University announcement and described as “a synthesis of scientific knowledge on greenhouse gases, climate change and food and environmental issues”— then moves to a potential means of curbing the emission of methane: reduce the number of cattle and other ruminant livestock, and tax meat.

The authors, who hail from universities in the U.S., Scotland, Austria, Germany and Australia, as well as a member from the Union of Concerned Scientists—a nonprofit out of Washington D.C. with stated positions counter to modern agriculture—contend that global domestic ruminants number around 3.6 billion, a population that has reportedly grown by 50 percent in the past 50 years. They also point out that methane is a vastly more potent greenhouse gas than CO 2 and is produced in much higher amounts per pound of food produced in the form of animal protein than in the production of plant-based proteins.

Livestock’s laughable shadow

Though still widely parroted in many areas of the media, the livestock-related statistics presented in Livestock’s Long Shadow were quickly debunked after the report’s release.

One of the primary issues it faced was an “apples to oranges” scenario in its famous livestock vs. transportation comparison.

“The comparison of livestock and transportation with respect to global [greenhouse gas] contributions was misleading because different methods were used to assess impacts,” explained Dr.

Frank Mitloehner, Associate Professor and Air Quality Specialist at University of California, Davis’ Cooperative Extension, and one of the U.S. scientists who tackled many of the questionable statistics put forth by “Livestock’s Long Shadow.”

Effectively, the report had compared the environmental impact of the entire livestock supply chain—the resources needed to grow the feed and supply the infrastructure of livestock production, in addition to the environmental impact of the animals themselves— to the single element of transportation emissions. If the environmental impact of the entire supply chain of global transportation had been considered, the comparison would have been on a more equal footing and looked very different.

Another “debunked” element of “Livestock’s Long Shadow,” which applies equally to the new climate change opinion piece, “Ruminants, Climate Change, and Climate Policy,” is that it discusses global averages, yet those statistics are inappropriately applied to specific countries, namely the U.S. While it is not the fault of the publications how groups or individuals misuse them, either maliciously or through ignorance, it is an important detail to keep in mind that both publications spoke about global averages, not U.S.-specific statistics.

According to a U.S. Environmental Protection Agency (EPA) 2011 report, the whole of American agriculture accounts for 6.9 percent of total U.S. greenhouse gas emissions. When a more segmented view is taken, livestock account for only 3.1 percent of total U.S. greenhouse gas emissions. If methane is the focus specifically, methane produced from all livestock is 2.8 percent of the total, and for beef cattle specifically it is just 1.5 percent of total U.S. greenhouse gas emissions.

By comparison, other contributors to total U.S. greenhouse gas emissions are fairly high, according to the EPA:

• Electricity generation, 33 percent;

• Transportation, 26 percent;

• Industrial use, 11 percent; and

• Residential and commercial use, 8 percent.

Other countries, however, are not nearly as efficient in their livestock and agricultural environmental impact as is the U.S. As a large portion of the world’s population live in developing countries where subsistence or nearsubsistence agriculture is the norm, efficiency of agriculture is hard to improve.

Mitloehner once pointed out when interviewed about “Livestock’s Long Shadow” that a U.S. dairy cow in California produces five times as much milk as a Mexican dairy cow. Similarly, the land needs of South American beef cattle are many times greater than in the U.S.

“The only way we can feed 9.3 billion people is to implement what we have learned in the developed countries with respect to improvements in efficiencies and apply these practices in the developing world, as well,” said Mitloehner.

The improved sustainability of the U.S. beef industry is well-documented and an ongoing effort. As can be seen in the infographic above, some laudable accomplishments in improved sustainability have been achieved in just six years, and all of this with historically low herd numbers.

Cutting herds and taxing meat

Despite the vast efficiency differences between livestock production in the U.S. and other first world nations compared to the developing nations, the authors of the new commentary recommend global herd reductions and taxing meat to shift consumer behavior.

“Reducing demand for ruminant products could help to achieve substantial greenhouse gas reductions in the near-term,” said opinion co-author Helmut Haberl of the Institute of Social Ecology in Austria.

The authors claim that reducing global herd sizes and consumer demand for meat from ruminants “offers greater greenhouse gas reduction potential than do other steps such as increasing livestock feeding efficiency or crop yields per acre.”

“Cutting the number of ruminant livestock could have additional benefits for food security, human health and environmental conservation involving water quality, wildlife habitat and biodiversity,” added co-author Pete Smith of the University of Aberdeen in Scotland. — Kerry Halladay, WLJ Editor