Those ‘environmentally friendly’ candles that many participants light? They are a fossil fuel — and burn almost 100 times less efficiently than incandescent light bulbs. (That’s why you won’t ever find a modern hospital using them instead of electricity). Using one candle for each switched-off bulb actually cancels out even the theoretical CO2 reduction; using two candles means that you emit more CO2.
Amazing how many suckers fall for Earth Hour every year.