For related articles and more information, please visit OCA’s CAFO’s vs. Free Range page and our Health Issues page.

Late last year, US Department of Agriculture chief Tom Vilsack boasted that US agriculture exports had hit an all-time high in fiscal 2013, and hailed “historic work by the Obama Administration to break down barriers to US products and achieve new agreements to expand exports.” Underlying Vilsack’s glee is the idea that growing huge amounts of food here and selling a big chunk of it overseas bolsters the US economy and stabilizes rural America.

That kind of thinking has driven agriculture policy at least since the days when Richard Nixon’s ag secretary Earl Butz exhorted farmers to scale up operations and plant “fencerow to fencerow” in order to supply foreign markets.

But a new paper (PDF) from Harvard suggests massive ag exports might not be the economic boon imagined by USDA secretaries. The researchers looked at a single farm pollutant, ammonia (NH3), which makes its way into the air from fertilizer applied to farm fields and from the manure that accumulates on livestock farms. Once it enters the atmosphere, as Erik Stokstad explained in an excellent (pay-walled) news item in
Science, it “reacts with other air pollutants to create tiny particles that can lodge deep in the lungs, causing asthma attacks, bronchitis, and heart attacks.”       

The Harvard team found data on the ammonia emissions associated with various major crops and meat products between 2000 and 2009, calculated what percentage of each commodity goes to exports, and figured out what share of total ag-based ammonia emissions come from growing food for export.