There's an amusing anecdote about an old lady who put saucers under her mains sockets in case the electricity leaked out on the carpet. But most of the rest of us are equally unaware of what really happens the other side of the socket - and what that might mean, not just for our carpets, but for our whole way of life. Most people know that we waste a lot of energy - and that producing it generates pollution. But for most people that's all rather abstract. As long as it runs the heating system, lights and video, who cares - especially as it's now quite cheap. However, we may have to start caring, since the way energy is generated and used could soon have a serious impact on our lifestyle. Most of our electricity comes from burning coal and gas - fossil fuels that won't last for ever and which create carbon dioxide gas when they are burnt in power stations. This gas is also produced by vehicle engines. Along with other so-called greenhouse gases like methane, it travels to the upper atmosphere and acts like the glass in a greenhouse, trapping the sun's heat. The result is global warming - a gradual rise in average global temperatures.