Young people from around the globe are striking from school on Sept. 20 in a global call for action, and asking adults to join them.

From the U.S. to Sweden and Germany to Japan and Hong Kong and more than 150 countries, roughly 2,500 coordinated protests will take place around the world. The goal is to make Friday the largest climate mobilization in world history — and to push government leaders to actually do something about it when they meet for the United Nation's Climate Summit in New York next week.

Friday's march will be followed by a second worldwide march on Sept. 27 marking the end of the global summit in New York and a window to the next chapter, when the U.N. General Assembly meets to discuss their plans to curb greenhouse gases under the 2015 Paris climate agreement.

It started with a single person

woman holds sign with a sketch of Greta Thunberg to demand climate action A woman holds a sign with a sketch of Greta Thunberg during a strike to demand action be taken on climate change outside the White House on Sept. 13 in Washington, D.C. Teenage Swedish climate activist Greta Thunberg joined the group as part of a six-day visit to Washington ahead of the Global Climate Strike scheduled for Sept. 20. (Photo: Sarah Silbiger/Getty Images)

Swedish teenager Greta Thunberg, who turned 16 in January, started striking in August 2018, following a series of heat waves and wildfires in Sweden. Each day for two weeks in the lead-up to that country's Sept. 9 election, she camped outside the country's parliament in Stockholm and handed out leaflets that read "I am doing this because you adults are [expletive]ing on my future."

When asked why she wasn't in school, Thunberg would retort, "I have my books here. But also I am thinking: What am I missing? What am I going to learn in school? Facts don't matter any more, politicians aren't listening to the scientists, so why should I learn?"

Logically, the argument may not flow, but rhetorically, it soars. And since then, she has been offering more advice to any interviewer or politician who dares to ask: In a nutshell, stop talking and do something.

Greta Thunberg holds a microphone during a Fridays for Future protest in Hamburg Greta Thunberg, seen here at a Fridays for Future protest in Hamburg, Germany, in March, started the student protest movement. (Photo: Adam Berry/Getty Images)

Following the election, Thunberg returned to school except on Fridays. On Fridays, she returned to the parliament building to continue her protest. Those weekly protests have evolved into the Fridays for Future movement. Students from the United Kingdom, Uganda, France, Poland, Thailand, Colombia and other countries organized their own Friday protests, skipping classes to march and to protest government inaction regarding climate change. That movement generated massive protests in March and May.

The popularity of the movement made Thunberg something of a celebrity activist. She gave a short but searing speech in January at the World Economic Forum, the annual meeting of industrial, financial and political titans rubbing elbows in Davos, Switzerland, in which she told the upper crust elites, "I want you to panic. I want you to feel the fear I feel every day. And then I want you to act."

Hong Kong Fridays for Future Students in Hong Kong protest on March 15, when thousands of young people marched through cities in Asia and around the globe. The March rally was one of the first to show how many people were prepared to march. (Photo: Anthony Wallace/AFP/Getty Images)

Thunberg has also been nominated for the Nobel Peace Prize. "We have proposed Greta Thunberg because if we do nothing to halt climate change it will be the cause of wars, conflict and refugees," Norwegian Socialist MP Freddy André Øvstegård told The Guardian. "Greta Thunberg has launched a mass movement which I see as a major contribution to peace."

Are adults paying attention?

A protest sign from the Global Climate Strike on Sept 20 says: In loving memory of Earth. She was only 4.5 billion years old. The signs run the gamut of emotions from sorrowful like this one to downright angry. (Photo: Maja Hitij/Getty Images)

Demanding that adults act is the only recourse some younger people have. They're not allowed to vote — a lowered voting age is one of the protesters requests, and who can blame them? They're not treated with a great deal of respect when they try and make their voices heard.

Then-British Prime Minister Theresa May's office dismissed the British protests earlier this year. "Everybody wants young people to be engaged in the issues that affect them most, so that we can build a brighter future for all of us," a spokesperson for May said. "But it is important to emphasize that disruption increases teachers' workloads and wastes lesson time that teachers have carefully prepared for. That time is crucial for young people, precisely so they can develop into the top scientists, engineers and advocates we need to help tackle this problem."

But it's hard to swallow that sort of "Children are our future (but only if they behave)" response when scientists tell us we only have 12 years to save the planet.

Since then, May has left office, some school officials have softened their stance on students missing school and many more people — young and old — have started paying attention. It's a key moment.

"This shouldn't be the children's responsibility. Now the adults need to help us," Thunberg says in a Global Climate Strike video. " ... If it's not you who should do it, then who else? If not now, then when?"

Why kids are striking for the planet
Inspired by Swedish activist Greta Thunberg, kids and teens around the world are protesting to get adults to act on climate change.