ACROSS AMERICA — Fifty-three years ago Saturday, planet warriors staged the first Earth Day, a celebration of eco-consciousness that now takes place in more than 190 countries and has grown to become the most widely observed nonreligious holiday in history.

There are plenty of ways to observe Earth Day, from parades and parties to cleanups, rallies and workshops.

The modern environmental movement that began 53 years ago has brought about a sea change in how Americans view climate change, and many now regard it as an existential crisis. This year’s theme is “Invest In Our Planet,” a prod to governments, businesses, institutions and the 1 billion Earth Day participant to devote their resources to fighting climate change.

Earth Week officially kicked off Friday. A live series continuing through the week touches on a variety of urgent issues, from climate restoration, regenerative agriculture, environment and social justice, supply chain resilience, plastic pollution, resource scarcity, food security, the green economy, biodiversity restoration, universal climate literacy, and others.

Panelists range from public and private sector leaders to activists, scientists, influencers and beyond. Here is the schedule for the Earth Day live events scheduled to take place during Earth Week:

Local Earth Day celebrations are planned widely in the United States and around the world. Flagship U.S. Earth Day events include:

Here are some things you can do on your own:

Did you know that parking the car and walking or biking to where you need to get would significantly reduce your carbon footprint?

That’s according to an Imperial College London study published in the journal Global Environmental Change. The study, the first to look at how lifestyle changes can reduce carbon emissions, found that was the case even in European cities where many people already walk and cycle to their destinations.

If every person joined with billions of others and planted a tree, an area the size of the United States could be reforested, increasing the world’s tree canopy by a third without disrupting agriculture or city development, and blotting out about 100 years of carbon emissions.

That’s according to “The global tree restoration potential,” the first study ever to look at how many trees the planet can support.

“Our study clearly shows that forest reforestation is the best climate change solution available today,” lead author of the study, ETH Zürich researcher Tom Crowther, said in a statement to National Geographic.

However, National Geographic said it could take more than 100 years to add enough mature forest to achieve significant carbon reduction, especially as about 40 billion tons of carbon dioxide — the result of burning fossil fuels — are added to the atmosphere every year, Glen Peters, research director at Norway’s Center for International Climate Research, told National Geographic.

The average American discards 80 pounds of clothing a year, and 85 percent of it ends up in landfills, where the material used to make it produces methane. Although carbon dioxide has a longer lasting effect on climate change, methane has more than 80 times the warming power of carbon dioxide during the first 20 years after it reaches the atmosphere, according to the Environmental Defense Fund.

One way to offset that is to stop buying cheap, trendy fashion that goes out of style quickly, according to Columbia Climate School at Columbia University. It’s often shipped from low-wage countries overseas, so the use of fossil fuels to get it here also adds to a person’s individual carbon footprint.

A more sustainable approach is to buy higher-quality, U.S.-manufactured clothing. Or even better, Columbia Climate School advises, buy vintage or recycled clothing at thrift and consignment stores or upcycle unwanted clothing in some other way.