Friday, April 13, 2012

How Much CO2 Do Internet Searches Generate?



Many of you would have heard a public service announcement on radio claiming that “performing two Google searches from a desktop computer can generate about the same amount of carbon dioxide as boiling a kettle of water” or about 7 grams of CO2 per second.


We are happy to report, upon researching online, that the above does not refer to a one-hit Google search taking less than a second to complete, which Google says produces only about 0.2g of CO2.

It is only when a Google or other Internet search engine search takes several attempts to find the object being sought, and which may last for several minutes, that the CO2 emission rises. Various experts put forward carbon emission estimates for such a search of 1g-10g depending on the time involved and the equipment used.


“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.”

A recent report by Gartner, the industry analysts, said the global IT industry generated as much greenhouse gas as the world’s airlines - about 2% of global CO2 emissions. “Data centres are among the most energy-intensive facilities imaginable,” said Evan Mills, a scientist at the Lawrence Berkeley National Laboratory in California. Banks of servers storing billions of web pages require power.

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. Google’s infrastructure sends you data from whichever produces the answer fastest. The system minimises delays but raises energy consumption. Google has servers in the US, Europe, Japan and China.


Researchers have also calculated the CO2 emissions caused by individual use of the internet. Alex Wissner-Gross’ research indicates that viewing a simple web page generates about 0.02g of CO2 per second. This rises tenfold to about 0.2g of CO2 a second when viewing a website with complex images, animations or videos.

A separate estimate from John Buckley, managing director of, a British environmental consultancy, puts the CO2 emissions of a Google search at between 1g and 10g, depending on whether you have to start your PC or not. Simply running a PC generates between 40g and 80g per hour, he says. Chris Goodall, author of “Ten Technologies to Save the Planet”, estimates the carbon emissions of a Google search at 7g to 10g (assuming 15 minutes’ computer use).

Nicholas Carr, author of “The Big Switch, Rewiring the World”, has calculated that maintaining a character (known as an avatar) in the ‘Second Life’ virtual reality game, requires 1,752 kilowatt hours of electricity per year.

Though energy consumption by computers is growing - and the rate of growth is increasing - Newcombe argues that what matters most is the type of usage.

If your internet use is in place of more energy-intensive activities, such as driving your car to the shops, that’s good. But if it is adding activities and energy consumption that would not otherwise happen, that may pose problems.


1. Limit the amount of time you spend surfing the Internet and viewing unnecessary websites such as entertainment websites or playing online games.

2. Do not generate, forward or transmit spam. Use a spam filter to reduce the amount of time you spend online deleting unwanted mail. BCC (Blind Carbon Copy) the names and e-mail addresses of your e-mail recipients to reduce the chances of their names being ‘harvested’ from your e-mails by spammers.

3. Use the Internet as a substitute for activities that would otherwise use more fuel, energy and resources, such as paying your bills at a bank, going shopping, purchasing newspapers and magazines or sending snail-mail.

4. Do not conduct unnecessary Google searches, such as looking up your own name or your friends’ names!

5. If you have a blog, social networking page or Facebook page, reduce the number of applications and animations you have. Keep it basic. If it’s taking too much time to load your page, chances are, it’s using up more energy and releasing more CO2 than it should.

(Source: Extracted and compiled from

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