This year, the world is witnessing one of the biggest youth-driven social movements of all time.

Tens of thousands of children and teenagers have already walked out of school in protest against the alarming lack of immediate action being taken against climate change.

And now, climate strikers have published an open letter in the Guardian pledging to “change the fate of humanity, whether you like it or not”—and it’s honestly spine-tinglingly powerful.

“We, the young, are deeply concerned about our future,” the letter begins. “Humanity is currently causing the sixth mass extinction of species and the global climate system is at the brink of a catastrophic crisis. Its devastating impacts are already felt by millions of people around the globe.

“Young people make up more than half of the global population,” it continues. “Our generation grew up with the climate crisis and we will have to deal with it for the rest of our lives. Despite that fact, most of us are not included in the local and global decision-making process. We are the voiceless future of humanity.

“We will no longer accept this injustice. We demand justice for all past, current, and future victims of the climate crisis, and so we are rising up.”

The next stage of this rise will come on March 15 — when the #FridaysforFuture school strike will come again on an unprecedented scale, with the letter vowing that “we will protest on every continent.”

Currently, according to the Guardian, there are about 500 marches planned for March 15, across 51 countries.

The global, uncentralised nature of the movement is making it almost impossible to properly chart, but it’s fair to say that it is literally sweeping across the world—with marches already planned across western Europe, the US, the UK, Brazil, Chile, Australia, Iran, India and Japan, to name a few.

The demands of the strikers are simple: urging world leaders to “treat the climate crisis as a crisis” and take action accordingly.

The letter echoes the call of 16-year-old Swedish climate activist Greta Thunberg, credited with having sparked the current movement, through her solo protests. Back in August, Thunberg decided that she wouldn’t go to school on Fridays, and would instead protest climate change outside the Swedish parliament buildings.

She then took the world by storm at the World Economic Forum in Davos in January, delivering a speech that went viral and piled pressure on world leaders to step up their action.

“Adults keep saying: ‘We owe it to the young people to give them hope.’ But I don’t want your hope,” she told the audience in Davos. “I don’t want you to be hopeful. I want you to panic. I want you to feel the fear I feel every day. And then I want you to act.

“I want you to act as you would in a crisis,” she continued. “I want you to act as if our house is on fire. Because it is.”

As the strikers point out in the letter, published on Friday, climate change is the “biggest threat in human history.”

“We will not accept a life in fear and devastation,” the letter continues. “We have the right to live our dreams and hopes. Climate change is already happening. People did die, are dying, and will die because of it, but we can and will stop this madness.

“United we will rise until we see climate justice,” it reads. “We demand the world’s decision-makers take responsibility and solve this crisis. You have failed us in the past. If you continue failing us in the future, we, the young people, will make change happen by ourselves.”

It finishes with this (and yes, we have goosebumps):

“The youth of this world has started to move and we will not rest again.”

(Imogen is content writer and editor at Global Citizen UK. )

Full Text of the Letter

We, the young, are deeply concerned about our future. Humanity is currently causing the sixth mass extinction of species and the global climate system is at the brink of a catastrophic crisis. Its devastating impacts are already felt by millions of people around the globe. Yet we are far from reaching the goals of the Paris agreement.

Young people make up more than half of the global population. Our generation grew up with the climate crisis and we will have to deal with it for the rest of our lives. Despite that fact, most of us are not included in the local and global decision-making process. We are the voiceless future of humanity.

We will no longer accept this injustice. We demand justice for all past, current and future victims of the climate crisis, and so we are rising up. Thousands of us have taken to the streets in the past weeks all around the world. Now we will make our voices heard. On 15 March, we will protest on every continent.

We finally need to treat the climate crisis as a crisis. It is the biggest threat in human history and we will not accept the world’s decision-makers’ inaction that threatens our entire civilisation. We will not accept a life in fear and devastation. We have the right to live our dreams and hopes. Climate change is already happening. People did die, are dying and will die because of it, but we can and will stop this madness.

We, the young, have started to move. We are going to change the fate of humanity, whether you like it or not. United we will rise until we see climate justice. We demand the world’s decision-makers take responsibility and solve this crisis.

You have failed us in the past. If you continue failing us in the future, we, the young people, will make change happen by ourselves. The youth of this world has started to move and we will not rest again.