a toxic problem. The participant wondered how that “tipping point” could be factored into a true-cost accounting of the food system.

A challenge brought up in regard to meat production was how to design a different system that would produce the amount of meat equivalent to that produced by concentrated operations and in a safe manner. Presumably, the costs to the environment of a small animal production system versus a concentrated production system would be similar as long as the total amount of animals produced is the same. In this respect, a participant remarked one of the goals should be to raise fewer total animals. He said, “The epidemiological evidence is overwhelming that our high meat diet is unhealthy.”

John Antle identified loss of farmer income as a cost of small-scale animal production. Much of what is driving the trend toward large-scale farming, he said, is the desire to generate household incomes that are comparable to those earned by professionals in nonagricultural sectors. For example, a wheat farmer in Montana cannot generate an income greater than about $30,000-$40,000 a year without more than 3,000-4,000 acres of land. He said, “you have got to keep those factors in mind…. There are fundamental economics driving what we see in terms of the scale of production.” Some audience members agreed that economics are driving the trend toward large-scale production, that any policy changes aimed at reducing some of the external costs associated with large-scale production would need to be done very carefully, and that choices about trade-offs would be paramount.

An audience member observed that the export of finished meat products is another factor driving the trend toward large-scale production, and that the cost of global trade also needs to be considered when evaluating the trade-offs associated with small- versus large-scale production.

UNCERTAINTY ABOUT THE MAGNITUDE OF SOME EFFECTS

Another major overarching theme of the open discussions was the challenge of quantifying effects. Throughout the workshop, participants considered a range of methodologies for quantifying health, environmental, and other impacts. Some methodologies seem especially well suited for certain effects. For example, participants in one of the working groups described LCA as the tool of choice for examining GHG emissions. But for other effects, like the cost of antimicrobial use in food animals, varying opinions were expressed on whether risk assessment would be a feasible strategy for covering all antibiotics across every animal species. Some workshop participants opined that the greater challenge is not quantifying effects, rather it is quantifying them with certainty. Many participants noted that the level



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