Greta Thunberg, one of the most recognizable young climate activists on the planet, is on the 251st week of her school strike protests, which call for immediate action to the growing climate crisis. She's also celebrating her high school graduation, marking the last school strike for the 20-year-old movement leader as a student.

On June 9, Thunberg shared her thoughts on the end of this personal era (including a call for continued protest) to Twitter, writing, "When I started striking in 2018 I could never have expected that it would lead to anything. After striking every day for three weeks, we were a small group of children who decided to continue doing this every Friday. And we did, which is how Fridays For Future was formed."

Thunberg's Fridays For Future effort is now a bonafide global movement, connecting striking students around the world and training future climate activists to make demands directly to their political representatives and international leaders. The organization leads a global climate strike every year on March 3, rallying millions of enthusiastic protesters over its four-year history.

"By clarifying an abstract danger with piercing outrage, Thunberg became the most compelling voice on the most important issue facing the planet," wrote TIME Magazine, awarding Thunberg the Person of the Year title in 2019.

A target of much political ire, Thunberg has used this momentum to speak at the United Nations and World Economic Forum, to protest at global climate conferences and on the frontlines of climate threats, and to take on the world's polluters directly. Now, she wants the focus expanded to other youth leaders — and climate movements — who are just as determined to make a difference.

"There are probably many of us who graduate who now wonder what kind of future it is that we are stepping into, even though we did not cause this crisis," Thunberg wrote. "We who can speak up have a duty to do so. In order to change everything, we need everyone."

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Read her full comments below:

School strike week 251. Today, I graduate from school, which means I’ll no longer be able to school strike for the climate. This is then the last school strike for me, so I guess I have to write something on this day.

When I started striking in 2018 I could never have expected that it would lead to anything. After striking every day for three weeks, we were a small group of children who decided to continue doing this every Friday. And we did, which is how Fridays For Future was formed.

Some more people joined, and quite suddenly this was a global movement growing every day. During 2019, millions of youth striked from school for the climate, flooding the streets in over 180 countries. When the pandemic started, we had to find new ways to protest.

With time, we started to get back on the streets again. We’re still here, and we aren’t planning on going anywhere. Much has changed since we started, and yet we have much further to go. We are still moving in the wrong direction, where those in power are allowed to sacrifice marginalised and affected people and the planet in the name of greed, profit and economic growth. They continue to destabilise the biosphere and our life supporting systems. We’re rapidly approaching potential nonlinear ecological and climatic tipping points beyond our control.

And in so many parts of the world, we are even speeding up the process. There are probably many of us who graduate who now wonder what kind of future it is that we are stepping into, even though we did not cause this crisis.

We who can speak up have a duty to do so. In order to change everything, we need everyone. I’ll continue to protest on Fridays, even though it’s not technically “school striking”. We simply have no other option than to do everything we possibly can. The fight has only just begun.