How much carbon dioxide (CO2) is put into the air during the production and distribution of orange juice? According to PepsiCo, the giant beverage manufacturer, each half-gallon carton of its orange juice results in the release of 3.75 pounds (1.7 kilograms) of CO2 into the atmosphere.

PepsiCo's Tropicana beverage division hired a team of experts to measure the carbon footprint of its orange juice supply chain. The Carbon Trust, a U.K.-based organization that addresses climate change, certified the accuracy of those results. It did so by mapping the product lifecycle; measuring the energy consumption at each stage of the lifecycle; converting that information into equivalent carbon dioxide emissions; and then adding the equivalent carbon dioxide emissions from each stage to estimate the product's greenhouse gas footprint.

Interestingly, the researchers discovered that neither manufacturing nor transportation was the biggest source of emissions. Instead, growing the oranges made the largest contribution to greenhouse gases. That's because citrus groves use a lot of nitrogenbased fertilizer, which requires natural gas for production. The fertilizer also breaks down and converts into greenhouse gases after it has been spread on the fields.

[Source: Pepsico and "How Green is My Orange?" Andrew Martin, The New York Times, Jan 21, 2009]