It's a stark statistic that organisers hope the nation keeps in mind as it joins the global Earth Hour movement, in which people are encouraged to turn their lights off for 60 minutes.

On Saturday, Earth Hour is hoping to shine a light on the positive contributions Australians can make to slow deforestation.

Trees provide animals with crucial food and shelter, help cool urban areas and remove carbon dioxide from the atmosphere, Earth Hour CEO Dermot O'Gorman said.

On average, two trees are destroyed every second across the country - equating to 70 million each year - with devastating consequences for the environment.

"Trees are the lungs of our planet," Mr O'Gorman said.

"If we want to secure a healthy future for people and nature, then we need to act with urgency to reverse the loss of nature and combat climate change by 2030."

Earth Hour is an opportunity to reflect on the actions needed to tackle the crises the environment faces, WWF Australia spokeswoman Kerri Major told AAP.

She hopes raising awareness of the benefits nature brings to communities and people's physical and mental wellbeing will encourage individuals to preserve the trees in their own backyards.

"Everybody can make a start somewhere," she said.

"Whether it is a decision to plant your own tree or not cut down a tree, you have that choice."

Critics argue the benefits of pushing for more climate change awareness are limited as there are few people in 2023 who do not know about the threat of global warming and environmental destruction.

But it is still important to keep talking about the issue so individuals feel empowered to make a difference, Ms Major stresses.

"The problem can seem really big and overwhelming, but we really want to reinforce the small, simple actions that people can take within their personal spheres of influence," she said.

"Collectively is where we start to see that bigger things can grow."

Although the novelty of the Australian-born Earth Hour initiative has worn off somewhat after 17 years, momentum around the world is still growing, Ms Major says. This year, 190 countries will take part.

The Sydney Opera House and Harbour Bridge will join landmarks around the world in going dark from 8.30pm AEDT Saturday.

Australian Associated Press