On March 31, we hope every home on your street goes dark. And wouldn’t it make your Saturday night out even more romantic if the restaurant served your dinner by candlelight? Plus your yard won’t think anything of it if you switch off the landscape lights for one measly little hour.

On an early spring evening in Sydney in 2006, Australians first answered World Wildlife Fund-Australia’s call for an hour without lights. Now it’s gone global.

WWF’s Earth Hour is a call for cities, business and individuals to switch off their lights for one hour at 8:30 p.m. local time the last Saturday in March. It’s a viral event—first dubbed “The Big Flick”—created to drum up support and awareness for lasting climate change action. The Saturday night blackout inspires people of every culture to become proactive about halting climate change.

Fundraising is an important part of effecting positive social change. But WWF’s Earth Hour is a great example of how working together and sacrificing a little convenience can make a difference without costing money.

Last year, over 5,000 cities and towns across the world switched off their lights to send a message about climate change. In fact, people’s enthusiasm for defending the planet by participating in Earth Hour has helped the event “Go Beyond the Hour.” Now Earth Hour is only the beginning. Consider turning your lights off on March 31 the first step in a lifelong commitment to sustainability.

As WWF points out, Earth Hour relies heavily on social media channels like blogging and Facebook to spread the word about this worldwide, world-changing event. Nonprofits and their supporters can spread good ideas with social media. And the more we share great ideas and activities such as Earth Hour, the better our world (and our climate).

Can you spare an hour of electricity this Saturday? In doing so you’ll participate in an international movement that’s found increasing success by raising awareness about climate change. One dark hour can make one big change—all you have to do is participate. Better still, recruit friends and family members to participate along with you.

Earth Hour is an event every person and every organization can get behind. WWF’s Earth Hour is your call to be proactive about stopping climate change. Will you answer it?