While that one hour does not really do much, it's more a symbolism thing, to show awareness. They were talking on the radio today how lot of the mines participate in this stuff, but they go further, such as take employee suggestions on way to cut pollution/energy use and they will actually practice those new things on a day to day basis after. So THAT is what makes a difference. If it takes something like Earth hour to raise awareness I think it did it's job. Though, electricity use does not really cause climate change given most of it comes from hydro dams here, the biggest impact is gasoline use, natural gas use, etc.