ON the last Saturday of March each year, millions of people and businesses all over the world switch off lights, appliances and equipment for just one hour, to celebrate sustainability and show support for strategies that will help solve the problem of global warming.Earth Hour was co-ordinated by the WWF and other volunteer organisations 10 years ago, and started in Sydney, Australia. To quote from its website: “Earth Hour is more than an event, it is a movement. “Over the past 10 years, we have achieved a massive environmental impact. With your support, we’re helping change laws, lives and our planet. How great is that?”This year, Earth Hour will fall on Saturday, March 24, from 8.30 pm to 9.30 pm. — Supplied.