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 Summer 2012


UCS Supports Sustainably Grown Food

Smarter Ways to Keep the Planet Cool” (Spring 2012, p. 7) misleadingly warns against buying local food to combat global warming. Our nation’s current food production not only entails shipping long distances but also uses vast amounts of irrigation, petroleum-based fertilizers, herbicides, and pesticides, as well as carbon-intensive processing, packaging, and corn and soy feeds for concentrated animal feeding operations (CAFOs).

Robin Hoy
Bucks County Foodshed Alliance
Wycombe, PA

UCS responds:

UCS strongly advocates for local and sustainable food systems (see our August 2011 report Market Forces to learn about their many benefits) and we strongly urge consumers to purchase such food. We are, however, reluctant to tout organic agriculture as a major solution to reduce heat-trapping emissions, as the science is not definitive in this area. As we discuss in our new book, Cooler Smarter, sustainable organic practices discourage inputs and therefore are likely to have fewer input-related emissions, but agricultural systems are complex. Some studies, for example, have shown that increasing carbon storage in soil can increase heat-trapping nitrous oxide emissions. And as we noted in our article, transporting food from farm to store accounts for only 4 percent of food-related emissions on average.

When it comes to reducing your carbon “foodprint” the strategy with the largest payoff is to eat less meat—particularly beef, which is responsible for more than three times the heat-trapping emissions of fruits and vegetables, and 18 times the emissions of pasta, on average.

What about Mercury?

[In “Smarter Ways to Keep the Planet Cool,”] it makes little sense to tell everybody to switch to CFLs [compact fluorescent lightbulbs] when they still contain mercury and no safe, simple disposal method has been provided. I find this particularly ironic at a time when the government is going to extraordinary trouble to eliminate other sources of mercury in the atmosphere.

Katharine W. Rylaarsdam
Baltimore, MD

UCS responds:

CFLs do indeed use mercury—about four milligrams (mg) on average—to produce light. However, the biggest source of mercury exposure is coal-fired power plants. About 1 mg of mercury emissions is released into the air when generating electricity to run a 13-watt CFL over the bulb’s 8,000-hour lifetime, assuming coal supplies 40 percent of that electricity (close to the national average). Most of the CFL’s mercury is bound to the bulb and is therefore harmless; thus, even with improper disposal (i.e., the bulb breaks), total CFL-related mercury emissions are only about 1.4 mg. Under the same assumptions, about 4.4 mg of mercury are released from electricity production for a 60-watt incandescent bulb (comparable in brightness to a 13-watt CFL).