What's the carbon footprint of sending a text message? Leo Hickman at The Guardian has an answer. He's contacted Vodafone, who have calculated it's 0.000003 grams of CO². That's based on last year's energy consumption from Vodafone, which used 2,600 gigawatt hours of energy to carry 60,000 terabytes of data. A text message has a maximum length of 140 bytes, which would take an average 5 microwatts-hour to transmit. Mind you, this doesn't include the energy used by the mobile phone or the energy used outside Vodafone's network... or the energy involved in making the phone.