Earth Hour, here's why millions of people around the world are turning off their lights

Here's what you need to know ahead of the 16th annual Earth Hour celebration.

Earth Hour was launched in 2007 by the World Wildlife Fund and its partners in Sydney, Australia, according to a news release from the organization. The non-profit organization describes Earth Hour as "the largest global grassroots movement for the environment".

"Earth Hour aims to raise awareness and spark global conversations about protecting nature, tackling the climate crisis and working together to shape a brighter future for us all," WWF says on the Earth Hour website . Earth.

The Earth Hour campaign has led to other actions related to curbing climate change. WWF's Uganda chapter, for example, created the first "Earth Hour Forest" in 2013. In addition, Argentina used its 2013 Earth Hour campaign to help pass a Senate bill for an 8.4 million hectare area protected marine species in the country, according to WWF.

To participate, all you have to do is turn off the lights in your home between 8:30pm and 9:30pm in your local time zone on Saturday.

Iconic landmarks like the Empire State Building in New York, the Space Needle in Seattle and the Willis Tower in Chicago will recognize Earth Hour by going dark.

How does turning off the lights help the environment?

According to WWF, turning off the lights is a "symbolic" way to raise awareness about climate change.

"Dark Hour takes us out of the busyness of our daily routines and allows us to reflect on the one home we all share," the organization said in its news release. "In the face of accelerating biodiversity loss and climate change, there has never been a more important time to come together and take action for our collective future."

The Earth Hour website notes that the planet is on track to reach over 1.5 degrees Celsius of warming, “doing so risks irreversible environmental degradation and climate change that will affect all societies and our economies".

The organization encourages participants to use their off hours "doing something positive for our planet."