Earth Hour 2013: World To Dim The Lights On Saturday, March 23

A record 7,000 cities in 152 countries are expected to turn off the lights for an hour on Saturday night for Earth Hour 2013.

Some of the world’s most famous landmarks — including the Empire State Building, Big Ben, the Sydney Opera House and the Burj Khalifa — will go dark from 8:30 to 9:30 p.m. local time during the seventh annual Earth Hour. The event started inSydney, Australia in 2007 when 2.2 million people turned off all non-essential lighting.

The initiative, led by the World Wildlife Fund, is meant to raise global awareness about climate change and extend beyond the hour-long event.

“The hour itself is symbolic,” Andy Ridley, executive director of Earth Hour, wrote in a blog entry on HuffPost. “It signifies their concern for the future of this planet, but it doesn’t mean an hour-long lights off is the one action they are committed to.”

One of the biggest changes to the program this year is an expansion of the ‘I Will If You Will’ challenge. Someone makes a promise to complete an action if enough people pledge to perform a green act, like plant a tree or walk to work (like this incredible video of a women pledging to get a tattoo of a happy panda if 10,000 people start recycling).

Critics of Earth Hour have downplayed its symbolic message and criticized its relatively minor impact on emissions. Yet, as HuffPost’s Tom Zeller Jr. notes, Earth Hour isn’t meant to “demonize electricity,” but rather “raise awareness about resource use, resource constraints and the looming consequences of doing precisely nothing to address climate change.”