Does surfing and searching Google generate CO2?

Google's response to Sunday Times story about its search and greenhouse gases (12 January, 2009)

Our sister paper the Sunday Times has caused something of a storm by publishing a story based on the research from a Harvard physicist who claimed that every Google search generates about 7g of CO2.

Here's the top of the story:

Performing two Google searches from a desktop computer can generate about the same amount of carbon dioxide as boiling a kettle for a cup of tea, according to new research. While millions of people tap into Google without considering the environment, a typical search generates about 7g of CO2.

Boiling a kettle generates about 15g. “Google operates huge data centres around the world that consume a great deal of power,” said Alex Wissner-Gross, a Harvard University physicist whose research on the environmental impact of computing is due out soon. “A Google search has a definite environmental impact.”

Google has been moved to respond on its official blog, saying that this estimate is *many* times too high. Here is the link to the blog. And here is the meat of the Google response:

In fact, in the time it takes to do a Google search, your own personal computer will use more energy than Google uses to answer your query.

Recently, though, others have used much higher estimates, claiming that a typical search uses "half the energy as boiling a kettle of water" and produces 7 grams of CO2. We thought it would be helpful to explain why this number is *many* times too high. Google is fast — a typical search returns results in less than 0.2 seconds. Queries vary in degree of difficulty, but for the average query, the servers it touches each work on it for just a few thousandths of a second. Together with other work performed before your search even starts (such as building the search index) this amounts to 0.0003 kWh of energy per search, or 1 kJ. For comparison, the average adult needs about 8000 kJ a day of energy from food, so a Google search uses just about the same amount of energy that your body burns in ten seconds.

In terms of greenhouse gases, one Google search is equivalent to about 0.2 grams of CO2.

What do you think? (http://timesonline.typepad.com/technology/2009/01/googles-respons.html)