When is Earth Day 2020 and what is it about?

This week marks the 50th anniversary of Earth Day, when millions of people around the world are expected to mobilise to protect the planet.

But with the majority of the globe in lockdown, 2020 will be slightly different with organisers asking people to rally online instead for the first ever Digital Earth Day.

Instead of filling parks, stadiums and the streets, people are instead being encouraged to use their "voices to drive action online rather than in person".

What is World Earth Day about?

Earth Day was first launched in 1970, when millions of people in America took to the streets to protest for environmental reform.

The brainchild of US Senator Gaylord Nelson, it was founded in the aftermath of the 1969 oil spill in Santa Barbara, California and led to the creation of landmark environmental laws and the Environmental Protection Agency.

Soon after the first Earth Day, the US passed the Clean Air Act, Clean Water Act and the Endangered Species Act.

First launched as a way to teach environmentalism and protest against the negative aspects of industrialisation, and set against the backdrop of rising public concern about the environment, Earth Day soon grew to become a global environmental movement.

More than a billion people worldwide now take part in marches, petitions and clean-ups to protect the environment - making it the largest civic observance in the world.

People all around the world are encouraged to do things to benefit the environment, from recycling and planting trees to reducing our carbon footprints.

However, this year will be slightly different with people encouraged to protest virtually, in order to prevent the spread of coronavirus.

Kathleen Rogers, president of Earth Day Network, said: "At Earth Day Network, the health and safety of volunteers and participants in Earth Day events is our top concern. Amid the recent outbreak, we encourage people to rise up but to do so safely and responsibly — in many cases, that means using our voices to drive action online rather than in person."

It means the 50th anniversary of the day will be the first ever Digital Earth Day, in which participants are encouraged to share the hashtags #EarthDay2020 and #EARTHRISE "in a collective call for transformative action for our planet".

Earth Day Network will provide live coverage of the "global digital mobilisations" online, and other digital events include virtual protests, social media campaigns, online teach-ins and more. Find out more at earthday.org.

"Whether it be coronavirus or our global climate crisis, we cannot shut down,” said Rogers. "Instead, we must shift our energies and efforts to new ways to mobilize the world to action."​

Each year, Earth Day has a different theme.

And the theme for 2020 is climate action.

Bosses say the "enormous challenge — but also the vast opportunities — of action on climate change have distinguished the issue as the most pressing topic for the 50th anniversary".