Google CO2 claim: a load of hot air?

In Monday's IT Blogwatch, Richi Jennings watches environmentalists accuse Google of emitting quite a lot of carbon dioxide -- but have they got the math wrong? Not to mention more Error'd...

Jonathan Leake and Richard Woods report:

Google logo
Performing two Google searches from a desktop computer can generate about the same amount of carbon dioxide as [making] 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.


Though Google says it is in the forefront of green computing, its search engine generates high levels of CO2 because of the way it operates. When you type in a Google search for, say, “energy saving tips”, your request doesn’t go to just one server. It goes to several competing against each other. It may even be sent to servers thousands of miles apart.

Om Malik waits to exhale:

Did you know that breathing for about 12 minutes emits roughly 7 grams of carbon dioxide into the air? According to a recent study conducted by Alex Wissner-Gross, a Harvard University physicist, that’s the same amount of carbon dioxide that’s emitted when you type in a search on Google.


Seven grams of Co2 might not seem like much — after all, a small car emits .59 pounds (or about 268 grams) per person, per mile. But consider how often you do a Google search.

Harry McCracken wonders about the tea-making thing:

I’m not sure what to make of that stat–is it a given that making a cup of tea is a more worthy undertaking than doing two Google searches? (The article’s in a British publication, so maybe so.)


Why get uptight about the environmental impact of something so basically useful as Googling until we’ve shut down all ferris wheels, shoe-polishing machines, factories that produce whoopie cushions, and other power-hungry institutions that aren’t essential to humanity’s survival?

SydShamino criticizes the comparison:

Were there not a Google (or internet equivalent), I wouldn't sit back in my rocking chair, exclaim "Oh, well," and have a cup or two of tea. Instead, I'd get in my car and drive to the library to look whatever it was up in a reference book, or search the catalog for a book I could borrow on the topic.

Google's Urs Hölzle rolls his eyes:

This number is *many* times too high ... 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 ... so a Google search uses just about the same amount of energy that your body burns in ten seconds.

But LeDopore gets out the calculator:

250g water in a cup of tea. Specific heat of water = 4186 J/kg/(degree C). 80 Celsius degree change.


To boil a teacup's worth of water, therefore it takes ~80 kJ. For this to be twice the energy consumed with one search, that's ~40 kJ per search. If a search takes Google about 100 ms, that means Google would be using 400 kW while responding to your search.

That feels like it's about 3 orders of magnitude too high. It's possible that the original researchers got Calories and kCal confused.

And Christopher Betts smells a rodent:

I get ... or 1/6th of the author's estimate, or 1/40th of the true kettle figure.

I'd say that the author is overstating the case to make a political point - if I was cynical I'd point out the author has also just launched a business to 'green your web site' ... so it is in his interests to overestimate such usage.

More at Techmeme

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Richi Jennings is an independent analyst/adviser/consultant, specializing in blogging, email, and spam. A 23 year, cross-functional IT veteran, he is also an analyst at Ferris Research. You can follow him on Twitter, pretend to be Richi's friend on Facebook, or just use boring old email:

Previously in IT Blogwatch:

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