You’re used to swiping your credit card at the gas pump, but would you also like having to swipe a card for your personal carbon units? While that may sound like a strange idea, a proposal to make every citizen carry a “Domestic Tradable Quota” card is actually being discussed in the UK. Under this radical plan, people would be given a certain number of carbon units annually, and would have to draw on those energy points every time they bought fuel or electricity. With such an energy spending limit, those who don’t use much energy could sell their credits to higher users, and the government would thus be able to oversee everyone’s personal energy use. Sounds like one credit-card offer best sent to the recycling bin.