Earth Hour dilemma: When the ‘Like’ button harms the planet
Green groups around the world are turning to social networking to drive their campaign for Earth Hour tomorow, when lights are turned off for an hour to signal concern about global warming.
But here’s the irony. With every email, every tweet, every appeal watched on YouTube or “liked“ on Facebook, environmentalists are stoking the very problem they want to resolve.
Each time we network, we emit carbon dioxide through the fossil fuels that are burned to power our computers and the servers and databanks that store or relay our message. That poses a small dilemma for the Australian-led campaign for Saturday’s switch-off.
In 130 countries around the world, people are being urged to turn off the lights for one hour at 8:30 p.m. local time as a show of concern about climate change. In emails alone, the typical office worker is responsible for 13.6 tons of CO2 or its equivalent per year, a French government agency for energy efficiency, ADEME, calculated last year.
That figure is based on a French company of 100 people who work 220 days a year and each receive 58 mails a day and send 33 per day, with an average mail size of one megabyte.That's 91 emails a day for 220 days = 20020 emails a year per person, and it's apparently responsible for a staggering 13.6 tons of CO2, or 679 grams of CO2 per email.
That seemed a lot of CO2 to send or receive a few dozen lines of text. 1 megabyte also seemed rather large for an average email, as I've rarely sent or received one larger than 100kb in size, but we'll let that pass, perhaps French office workers send lots of pictures as attachments.
How much electricity does 679 grams of CO2 represent? The EPA says that a gas-powered station produces 1135 lbs CO2 per MWh (megawatt-hour). One pound is 453.6 grams, so 1 MWh produces 514826.92 grams, therefore I calculate 0.758 KWh per email. That's around 3 desktop computers running for an hour, the equivalent of a one-bar electric fire for 45.5 minutes, to send or receive a one megabyte email?
Every time I come across this type of claim, the maths doesn't support the claim, not just a little bit out, but often whole orders of magnitude.
Feel free to comment, safe in the knowledge you're not fuelling irreversible climate change (but stop breathing out CO2, just in case).