Actually, anyone that knows how turning off a large load unevenly and turning a large load back on affects the electricity grid knows perfectly well that doing

Actually, anyone that knows how turning off a large load unevenly and turning a large load back on affects the electricity grid knows perfectly well that doing that necessitates increasing energy production. The short explanation is that large simultaneous changes in the electricity grid will create shocks which make it difficult to maintain the voltage at every point of the grid. Changing electricity distribution is not actually that fast country-wide, so the electricity company must put the largest possible load into the grid. When it is randomly reducing that is the load that was on the grid before the reduction, when the load is increasing that is a certain percentage above the point it's increasing to, generally ~20% more. Get it wrong and large amounts of electrical equipment will be confronted with a way too low, or way too high voltage on the sockets. Low is bad (stuff doesn't start, washers get "stuck", ...), equipment gets damaged because it can't be kept operating, which may cause fast on-off cycles that destroy electrical motors pretty quickly. Too high is VERY bad, for obvious reasons. The way to compensate for that is to put more energy in the grid so that every distribution box is capable of getting the local lines up to 240V, and destroy the excess at local distribution stations. If the load is very predictable that energy destruction can be kept to very low values, if it's not, you have to raise them. So to make the farce of earth hour complete, electricity companies prepare for earth hour in Australia (earth hour's home turf) by ... increasing the output of local coal power plants, the worst offender for global warming ... Granted, the difference is probably small, but earth hour is definitely making things worse, not better. You just can't make this up. Earth hour is a publicity stunt, meant to channel money and attention into it's parent publication, nothing more. It should be treated like any other pop-up ad.