Hey, Computer User, What's the Carbon Footprint of the Internet?

Sal holds a political science degree from the George Washington University. He's written about all things environment since 2007.
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Internet surfing at what carbon cost? (Photo: Stringer Shanghai / Reuters)

For myriad reasons, determining the carbon footprint of the Web is a challenge.

How many hundreds of millions (or is it billions) of computers are online on a daily basis?

How much energy do those countless computers consume?

How much energy do offline Internet jobs—like, say, data entry into a Microsoft Excel document—require?

Despite this mountain of maybes, The Guardian found a way to measure the CO2 output of the Internet.

It’s 300 million tons per year, give or take.

Given the computational uncertainties, how exactly did the Guardian arrive at a carbon footprint that’s equivalent to every person in the United Kingdom flying to the United States and back twice over?

They used a step-by-step process.

Step One: Establish a foundational baseline. In this case, they looked to data centers. According to a study conducted in 1997 by Gartner, data centers—facilities used to warehouse ranks of powerful computers—accounted for 25 percent of energy consumed and carbon emitted by the information and communication technology (ICT) sector.

Step Two: Establish another foundational baseline. This time, they looked to the world’s PCs and monitors, which combine to constitute 40 percent of ICT energy demand.

Step Three: Take a leap of faith. For arguments’ sake, the Guardian decided that half of the emissions from Step Two were caused by Internet activity.

Step Four: Add the number from Step Two to the number from Step Three.

Doing all of that got The Answer: the Internet accounts for approximately 1 percent of worldwide C02 emissions.

Turns out, the Guardian's fuzzy math may actually be quite clear.

Another study, conducted by the U.K.'s market transformation program, ascertained that ICT accounted for 343 million tons of C02 in 2005, or roughly 1.2 percent.

The real question, of course, is that while the Internet might be a small percentage of worldwide C02 emissions now, will advancements in clean computer technology outpace the exponential expected growth of the Internet worldwide?

Stay tuned.

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