Saturday, January 17, 2009

Google's Storm in a Teacup

googlekettle

The UK Times recently ran a story on the environmental impact of Google searches. The article asserted that two Google desktop searches (at 7g of CO2 each) had about the same carbon footprint as boiling a kettle for a cup of tea (at 15g of CO2). Following the link to the original story now shows that the article has been clarified - I would like to say corrected after a flurry of criticism, but its not that simple.

Google quickly replied that their estimated cost of a search query was 0.2g of CO2, considerably less than the 7g given by the Times. The authors state that driving an average car for one kilometre produces as many greenhouse gases as a thousand Google searches, under the current regime for EU standard for tailpipe emissions. The Times has later clarified that by search they meant an activity lasting several minutes, and not simply a single Google query. Other people have also produced CO2 estimates for search in the 1g - 10g range, but upon inspection, these estimates also assume search to be an activity that the user performs for 10 to 15 minutes rather than a service provided by Google. Your computer has a 40g - 80g footprint per hour simply due to being turned on and surfing around a bit.

Gartner has remarked that for the first time in 2007 greenhouse gases produced to power the Internet have surpassed the total emissions of the global airline industry. This is quite ominous since we normally don't think of airlines as being particularly clean or the Internet as being particularly dirty. But its all about power consumption produced by burning fossil fuels. Power is mainly used by personal computers, the network and data centres. The largest power consumer here are personal devices, and there is some debate over the order of second and third places. I think the network.

Part of the controversy of the original story was that the 7g search cost was attributed to young Harvard physicist Alex Wissner-Gross. The clarification to the Times article now includes a link to a new article by Wissner-Gross where he gives some opinions on CO2 emissions, but actually few details. Apparently his main work on Internet CO2 consumption is being reviewed by academic referees before formal publication, so we must wait for his detailed analysis. Oddly enough Wissner-Gross, who took umbrage at being attributed as the source for the 7g Google estimate, now openly states that the correct figure is 5g - 10g.

The original statements of the Times, and perhaps even those of Wissner-Gross, can be traced back to the work of Rolf Kersten, who presented a talk called Your CO2 Footprint when using the Internet at a German Ebay conference in 2007. His findings are summarized in the table below.

Web Service

CO2 Emission

One Google search

6.8 g

One EBAY auction

55 g

One blog post on blogs.sun.com

850 g

A SecondLife avatar, 24hrs „alive“ for one year

332 kgs

Yes that is kilograms for the SecondLife avatar! Hr. Kersten has recently changed his estimates in light of the recent events and technology improvements, and stated that he overestimated by a factor of 35:

I was wrong. Very wrong. Wrong by a factor of 35. Wrong even when you take into account that Moore's Law and Google engineers had 20 months to increase efficiency since my first guesstimate.

So now we have it: One Google Search produces as much CO2 as 10 seconds of breathing!

You can review the details of the calculation in a latter article. Hr. Kersten is now in agreement with the 0.2g figure given by Google.

So in the end its just more than 70 Google queries to consume the same energy boiling a a kettle.

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