Earth Hour was started in 2007 in Sydney, Australia with great results. Earth Hour 2008 spread to cities all over the world, including Chicago which had impressive results. The Chicagoland region reported an electricity savings of 7% which is the carbon emissions equivalent of taking 1 million cars off the road for one hour or planting 158 acres of trees.
What’s really awesome about this day is that there are a ton of restaurants/bars who are having a special events to coincide with Earth Hour so don’t stay in and wait for the hour to be done with, go out and enjoy it!
Even Google will turn the lights off on their homepage by changing their trademark bright white screen to black in order to save energy on everyone’s computer.

Chicago's Earth Hour 2008

Sydney's Earth Hour 2008
