A story in the UK's Times Online set the green blogosphere ablaze with a simple statistic: Physicist Alex Wissner-Gross said that a single Google search emitted seven grams of CO2. Like many other bloggers, I wrote about the findings, and included a few eco-friendly search alternatives.
Google has since disputed the claim. According to the Google blog, one google search releases 0.2 grams of CO2, instead - a huge difference. Here's what Google has to say:
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.
So, how could Wissner-Gross' calculations have been so wrong? Well, he's now claiming he never made them in the first place - though the Times has not posted a correction on the story.
"For some reason, in their story on the study, the Times had an ax to grind with Google," Wissner-Gross told TechNewsWorld. "Our work has nothing to do with Google. Our focus was exclusively on the Web overall, and we found that it takes on average about 20 milligrams of CO2 per second to visit a Web site."
And the example involving tea kettles? "They did that. I have no idea where they got those statistics," Wissner-Gross said.
Another story about the dispute says that Wissner-Gross said he did discuss Google with the paper, but only in broad generalizations.
Readers also pointed out to me that the study's numbers seemed impossibly high. One reader, noting the eco-friendly search alternatives listed, however, had a succinct opinion. From John of Indiana:
"Either continue to use a search engine that (regardless of whether or not the contribution is significant) does release carbon, or use a similar search engine AND help contribute to improving our state of existence on this planet."