Friday's global climate strike involving students from 90 countries and more than 1,200 cities could be one of the largest environmental protests in history, according to CNN.
Thunberg said she's excited about the growing movement and explained to The Guardian how it started for her.
“I overthink. Some people can just let things go, but I can’t, especially if there’s something that worries me or makes me sad,” she said.
“I remember when I was younger, and in school, our teachers showed us films of plastic in the ocean, starving polar bears and so on. I cried through all the movies. My classmates were concerned when they watched the film, but when it stopped, they started thinking about other things. I couldn’t do that. Those pictures were stuck in my head.”
So, she took action, inspired by the Parkland school students who protested gun violence after a massacre at their high school.
Thunberg said world leaders are still resisting taking any action on the warming climate.
“They are desperately trying to change the subject whenever the school strikes come up. They know they can’t win this fight because they haven’t done anything.”
Thunberg is hoping that will change as more and more people join the movement.
Scientists around the world agree that climate change is already here. Since the early 1900s, the world’s climate has warmed by 1.8 degrees Fahrenheit.
A recent United Nations report determined that greenhouse gas emissions must be slashed in half by 2030 or the world could see a mass die-off of coral reefs, worsening water and food shortages and increased wildfires.