Long before Delenn Kershaw ever heard the term eco-anxiety — feeling overwhelmed by the existential challenge of climate change — the 19-year-old Scarborough teen said she experienced it.

"I had no idea about it, but I felt it, I very much felt it," Kershaw told CBC News on Friday.

"I definitely felt it ... the fear of the future, what we might be losing, and feeling so small in such a global monster of an issue."

Inspired by teenage Swedish climate activist Greta Thunberg, Kershaw said she is now part of a global movement calling for action to combat climate change.

Kershaw has launched a local chapter in Scarborough of Fridays for Future — a youth-driven movement started after Thunberg skipped school and staged sit-ins on Fridays outside the Swedish Parliament.

"When the youth come out to these events I think it gives that face-to-face hope that they're not alone," Kershaw said.

"When they rally [at] climate strikes ... they're able to have that dialogue and figure out where they fit in this big issue, where they can have the most impact."

A just transition from fossil fuels

Kershaw was among hundreds of students who skipped school and took to the streets in Toronto on Friday to demand action on climate change.

That protest followed September's climate strike when tens of thousands of young people stayed away from classes to protest.

"In September, 7.5 million people around the world took to the streets. Tomorrow we're doing it again. Everyone's needed. Everyone's welcome," Thunberg posted on social media as she rallied young people to join the latest protest.

Hundreds of youth activists from across the GTA took part in a Fridays for Future protest at Nathan Phillips Square on Friday. (Martin Trainor/CBC)

Kershaw said her Fridays for Future Scarborough and other chapters in the GTA are focused on specific issues.

One is "a just transition" from oil and fossil fuels to clean energy.

"The key there is having jobs, promising jobs to the people that rely on that fossil fuel industry. That's a big point of contention in the prairies and that's something that can equally benefit us all," Kershaw said.

A global monster of an issue. - Delenn Kershaw

Another agenda item is "rights for Indigenous communities, because they're one of the most affected by climate change," Kershaw said.

"By highlighting that and getting some action there, I think it's really, really important, especially in the spirit of reconciliation."

Meanwhile, Yusur Al Sharqi and Malak Elassiutoi were also among the hundreds who gathered at the steps of the Ontario Legislature to send a message to lawmakers.

"Climate change affects everybody, not just marginalized groups. It affects people in power, even the rich," Al Sharqi said.

"So, this is an issue everybody should care about and we want our voices to be heard."

Malak Elassiutoi, left, and Yusur Al Sharqi. (Martin Trainor/CBC)

Elassiutoi said, initially, her mom was not on board with her skipping school, but eventually allowed her to "because she knows I'm passionate and she knows we're making a difference today."

She wants to send a direct, urgent message to politicians.

"We want people in government and in power to start making changes because we're not going to have a future if this is what it looks like," Elassiutoi told CBC News.

Jake Belman, another Fridays for Future organizer, said youth need Canada to achieve a net-zero carbon target by 2040.

"This means no fossil fuel projects. Keep it in the ground. That's going to require a lot of change," he said.

"A lot of jobs will be lost so we need a just transition for fossil fuel workers."

The young activists say that until they get their wish, they will continue to skip classes on Fridays to protest.

The United Nations climate change summit, COP25, will take place in Madrid from Dec. 2 to Dec. 13.