Dozens of young people who dropped to the ground for a "die-in" protest in downtown Vancouver marched through city streets, joining millions of other activists across the globe in a mass climate demonstration.

Teens, children and their parents gathered at the base of the Vancouver Art Gallery steps late Friday morning, with a girl as young as seven holding her own cardboard sign with a plea for pollution to stop. Adults stood alongside the younger generation, carrying signs praising the activism.

"I've been really scared for my future because of the climate crisis and I really needed to do something about it," said Grade 10 student Lilah Williamson, speaking outside the gallery as peers cheered around her.

"I'm not old enough to vote, I'm not an adult yet, but this is a really great way to share my voice and show this is something that needs to happen, now."

Millions of students and workers abandoned schools and offices on Friday to demand urgent action from global leaders to stop climate change as part of a worldwide strike inspired by 16-year-old Swedish activist Greta Thunberg.

A large crowd of climate activists marches along West Georgia Street in Vancouver. (Maggie MacPherson/CBC)

The Vancouver protesters moved into Pacific Centre, a mall across the street from the gallery, and dropped to the centre's tile floor in unison for the die-in portion of the demonstration. Some lay quietly with their eyes closed, pretending to be dead, and others stared blankly at the ceiling.

Passing shoppers stepped around the bodies. Diners in the food court stopped eating and watched as the protesters lay on the floor for 11 minutes — one minute for every year left before 2040, when scientists believe the climate crisis could be irreversible without drastic action now.

Next, they moved on to the offices of mining company Teck Resources on Burrard Street.

A die-in is a non-violent form of protest in which participants lie on the ground, feigning death, to symbolize what will happen — or what has happened — because of leaders' inaction or action.

A student lies on the floor at Pacific Centre mall in Vancouver as part of a global climate strike on Sept. 20, 2019. (Maggie MacPherson/CBC)

Worldwide, demonstrations that started in the Pacific islands followed the rising sun across Australia, Japan, Southeast Asia and then on to Europe, Africa, the Middle East and the Americas. Crowds gathered in Europe, the Middle East and Africa, including London, Paris, Brussels, Berlin, Warsaw, Stockholm, Helsinki, Beirut, Nairobi and Cape Town.

Demonstrators in Antarctica stood huddled with signs sending "love and hope" from the world's southernmost continent. Three million people had participated worldwide as of midday ET.

Thunberg has staged weekly demonstrations over the past year under the heading "Fridays for Future," calling on world leaders to step up their efforts against climate change.

An activist stands in front of the Vancouver Art Gallery on Sept. 20, 2019, taking part in one of dozens of demonstrations around the world as part of a global climate strike. Millions of students and workers abandoned schools and offices on Friday to demand urgent action to stop global warming. (Maggie MacPherson/CBC)

The strike will culminate Monday in New York when Thunberg, who has been nominated for a Nobel Peace Prize for her climate activism, will spearhead a rally at the United Nations headquarters.

The Fridays For Future website lists more than 100 climate strikes planned across Canada.

Students at the University of British Columbia and young people in Surrey were also expected to participate in their own events Friday.

"It is so important that people take a stand. Governments say they recognize this but they're not moving fast enough. The science is clear that we need to move very urgently," said Allison Richardson, who has organized a demonstration at Surrey's Holland Park.

A teen activist with Sustainabiliteens lies on the floor at Pacific Centre mall in Vancouver as part of a global climate strike on Sept. 20, 2019. (Maggie MacPherson/CBC)

Some Canadian boards and administrations are supporting the global call to action and moving to allow — or even encourage — students to miss class for the cause. UBC is advising students taking part in the walkout to discuss possible accommodations with their instructors.

Many elementary and high school students were already out of class Friday for the first Pro-D day of the year.

Young activists stand in front of the Vancouver Art Gallery on Sept. 20, 2019, taking part in one of dozens of demonstrations around the world as part of a global climate strike. Millions of students and workers abandoned schools and offices on Friday to demand urgent action to stop global warming. (Maggie MacPherson/CBC)

A CBC Vancouver original podcast, 2050: Degrees of Change, explores how our world and lives will adapt to climate change within the next 30 years. Listen on Apple Podcasts, iTunes, the CBC Listen app or cbc.ca/podcasts.