Google’s Carbon Footprint: Does a Harvard Prof’s Claims Put Google in Hot Water?

Harvard professor Alex Wissner-Gross made waves recently by suggesting that making a couple of Google searches are just as bad for the environment as the cup of tea you drink while you’re making them (he has since backed away from the claim ). Wissner-Gross’s study says that the energy needed to power Google’s servers and storage, combined with connecting to and running your own computer, creates about 7 grams (about 0.25 ounces) of carbon-dioxide emissions per search. At that rate, he says, two quick searches cause the same amount of carbon emissions as does creating enough energy to boil a kettle of water.

Google, on its official blog, quickly fired off a retort in defense of its greenness, saying 7 grams was “many times too high.” The true figure, they say, is more like 0.2 grams of greenhouse gases at most. How could the two figures be so disparate? For one thing, it depends what you include in your calculations, which presents a challenge because Google tends to be tight-lipped about the technical details of its operations. But just as important, attempts to quantify carbon emissions all the way from Google’s servers to your home computer leaves plenty of mathematical wiggle room.

For instance, consider Wissner-Gross’s own example of choice—the tea kettle. An average gas produces about 9000 Btu per hour and takes around 9 minutes to boil a full kettle, meaning that it uses 1350 Btu. Wissner-Gross used an electric kettle in his example, according to The Guardian. A 1500-watt kettle can boil your water in only 5 minutes, bringing down the energy usage to about 426 Btu, less than one-third of the gas total. But an electric kettle’s emissions could vary wildly depending what the local plant used as an energy source. The U.S. burns coal for half of its electricity, which produces more CO2 per Btu of energy released than the other major fuel sources. The other half comes largely from natural gas, which creates less CO2, and nuclear power, which produces negligible CO2 but creates nuclear waste, which poses a different environmental worry.

Those are some of the complications of calculating just a tea kettle’s emissions. Wissner-Gross’s study attempts compare an average kettle’s emissions to the whole gamut of a Google search—all the emissions caused by the company’s servers and storage facilities, your computer’s power needs, the power needs of your Internet provider and more. Thus, equating two Google searches to any amount of boiling kettles is an oversimplification.

However, the study raises a bigger point: Information technology contributes 2 to 3 percent of global carbon emissions, and its share stands to grow as more people go online and spend more of their day with a computer running. Determining the energy use of IT throughout the process, from Google’s servers to your desktop, may prove a herculean task of calculation, but it’s one that Google and its competitors grapple with as they try to go carbon-neutral while the Web boom continues throughout the world. —Andrew Moseman

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