Source:  Tom Johnston, MEATINGPLACE.COM, 10/6/10

People need to begin limiting the amount of meat they eat to curb greenhouse gas emissions, nitrate pollution and habitat destruction, according to a new study by Canada’s Dalhousie University.

The study, titled “Forecasting potential global environmental costs of livestock production 2000-2050,” projects that the livestock industry alone would exceed global thresholds for climate change and habitat destruction by mid-century. The authors, Nathan Pelletier and Peter Tyedmers, call for worldwide cuts of average per-capita meat consumption of 19 to 42 percent by 1950.

Published Monday in the journal Proceedings of the National Academy, the article fans the flames of an intensifying debate about the true extent of the livestock production’s contributions to global warming. Questions also abound regarding the industry’s sustainability amid projections that meat production will have to double by 2050 to feed a population that will grow by 2.2 billion people in the next 40 years.

Meat-industry advocates are doing research of their own. A recent review by the International Meat Secretariat, details of which were discussed last week at the World Meat Congress in Argentina, acknowledges that agriculture is a major contributor of greenhouse gas emissions and needs to improve its environmental sustainability. But its precise contribution to environmental woes is unknown amid a wide variation in methods of measurement between different livestock production systems and species.

Doing the math

Cledwin Thomas, one of the authors of the IMS review, said in his presentation that there have been many new studies since the Food and Agriculture Organization estimated in 2006 that the livestock sector accounts for 18 percent of the world’s greenhouse gas emissions. Some of the newer studies estimate the number to be higher, and some project it to be lower, he said.

“One of the causes of this variation…firstly there’s the inherent errors and uncertainties in the metrics we use to calculate greenhouse gases,” he said. “In some areas we’re more precise than others. We’re much better at predicting methane losses from rumens than we are nitrous oxide from lamb, which have very high errors of prediction.”

The IMS research acknowledges the potential hazards of intensifying production. It calls for increased efficiency through the use of several available technologies, including improved capture of nutrients from manures, versus producing more animals.

“We have very many conflicting outputs,” Thomas said later in a press conference. “We have systems that produce very high ecological benefits, but they also produce high levels of greenhouse gasses. This is a big dilemma: How do we rationalize good contributions and environmental benefits in one direction with a bad effect in another?”

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