Product’s Carbon Footprint Found Tough to Compute

Companies looking to calculate their products’ carbon footprints — the greenhouse gasses contributing to climate change — may find taking those measurements more difficult than they anticipated. A recent study by Carnegie Mellon University’s (CMU’s) Christopher Weber found that the calculation of carbon footprints for products is fraught with large uncertainties, particularly related to the use of electronic goods.

Weber is an adjunct professor of civil and environmental engineering at CMU in Pittsburgh, Pennsylvania and a research staff member at the Science & Technology Policy Institute in Washington, D.C. He focused, as a case study, on the carbon footprint of an IBM computer server, accounting for the production, delivery, and use of the server.

Because of a server’s relatively long lifetime, the use phase accounted for nearly all, about 94 percent, of its total carbon footprint. But Weber found that the use phase of an electronic  product like a server is where much of the uncertainty arises in making these calculations.

While the product design can make the server’s use of electric power more efficient, the various ways of generating electric power — from fossil fuels like coal to renewable fuels such as wind or hydro — create huge uncertainties in estimating potential greenhouse gas.  Weber estimates the carbon footprint computations for a product’s use can vary up to 50 percent.

Production and delivery account for only a small portion of the total product footprint, but are somewhat more reliable, according to Weber’s calculations, with variances of 15 and 25 percent respectively. The use of air freight for delivery, and distances from factory to customer add much of the delivery variations.

Photo: ezioman/Flickr

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