Have you seen the Earth Hour campaign? Seems incredibly stupid to me. Not only is the message the usual “ask the government to do more” (Isn’t it easy to fix the world’s big problems? Limit your own effort to an hour and ask someone else to solve the rest) but it also seems like a hugely wasteful and, actually, climate-damaging idea. Power plants are not made for coping with huge step changes in demand, and that this gimmick is likely to cause a lot of headache for power plant operators. Millions of people all turning off their lights and appliances at the same time, and then on again within minutes of each other, will put a lot of strain on the power system. Do something meaningful instead: hang your laundry to dry instead of using a tumble dryer, or use public transport instead of a car.