We are exponentially growing our computing power and we’re filling it up with our videos, texts and tweets. All of our digital lifestyles have a physical presence out there and that physical presence has to be powered by non-renewable energy resources. The paradox is that the more efficient you make it to communicate with people and to send things, the more you’re going to do it. So instead of consuming less you actually consume more. And: A key part of this is something called “the rebound effect,” whereby you have a lower carbon technology but you actually have a higher C02 output, simply because you’re using it more. An email is 1/60th the carbon footprint of a letter, but when was the last time you sent a letter?