Unlike the similarly named Earth Day, Earth Hour is just that: one hour in length. First conceived in 2007 by the World Wide Fund for Nature (WWF) and The Sydney Morning Herald, Earth Hour is a time when households and businesses are encouraged to shut off their non-essential lighting to raise awareness about the need to act on global climate change.
In 2007, 2.2 million residents of Sydney, Australia participated in the first event by turning off all their non-essential lights. Following the lead of Sydney, many other cities around the world adopted the event in 2008. Earth Hour 2012 will take place on March 31, 2012 from 8:30 p.m. to 9:30 p.m., at the participant's local time.
Already, as the Earth spins beneath humankind and time changes across the planet, iconic monuments to humanity have gone dark.
Sydney's iconic Harbor Bridge and Opera House already have gone dark for an hour on Saturday.
Hundreds of other landmarks across the globe, including Washington's National Cathedral, London's Big Ben clock tower, the Great Wall of China and Tokyo Tower are being dimmed --- not necessarily turned off completely --- at 8:30 p.m. local time.
Andy Ridley, co-founder and executive director of Earth Hour said,
"We are living beyond our means. That is not sustainable. We want to unite people around the world to build a sustainable future."
The number of people and countries participating in the event has increased annually. Ridley, however, is concerned that things are still not moving quickly enough.
"We need to move a lot further, faster and as soon as possible. That is the big challenge, that we all move and that the economies can adapt to the change."