Mobile phones to track carbon footprint Keeping track of your carbon footprint could become as simple as slipping a mobile phone in your pocket: a London-based start-up company has developed software for mobile phones that uses global positioning satellites to work out automatically whether you are walking, driving or flying and then calculate your impact on the environment. Carbon Diem's inventors claim that, by using GPS to measure the speed and pattern of movement, their algorithm can identify the mode of transport being used. It can therefore calculate the amount of carbon dioxide that a journey has emitted into the atmosphere – without any need for input from the traveller. The system's inventor, Andreas Zachariah, a graduate student of the Royal College of Art in London and chief executive of the Carbon Hero company, said that Carbon Diem is the world's first automated carbon calculator. Because it keeps a constantly updated diary of a person's carbon emissions, Zachariah said that a user can easily track their environmental impact and, if they choose, modify their behaviour to lower-carbon alternatives....