On September 20, an estimated 4 million people in 161 countries took to the streets in the largest climate change demonstration in history.
At the helm of this Global Climate Strike was 16-year-old Greta Thunberg, who has entered the global spotlight over the last year as the leader of a youth movement that's pushing governments and corporations to address the climate crisis.
Thunberg launched the "Fridays For Future" movement — or School Strike for Climate (as it says in Swedish on her sign) — in 2018, encouraging students to skip school to demand action on climate change from their governments. In November, when she was a ninth grader, Thunberg staged a strike for two weeks outside the Swedish parliament, demanding that the government cut emissions by 15% a year.
Now Thunberg spends every Friday on strike.
On Monday, Thunberg gave an impassioned, tearful speech to world leaders at the UN Climate Action Summit.
"This is all wrong. I shouldn't be standing here. I should be back in school on the other side of the ocean," she said with tears in her eyes. "Yet you all come to me for hope? How dare you! You have stolen my dreams and my childhood with your empty words."
To get to the UN event, Thunberg sailed across the Atlantic on a zero-emissions boat to avoid the carbon emissions that would have come from flying.
On Monday, Thunberg joined two other youth activists in opening the UN Climate Action Summit. With tears in her eyes, she chastised world leaders: "You have stolen my dreams and my childhood with your empty words."
"This is all wrong. I shouldn't be standing here. I should be back in school on the other side of the ocean," she added. "Yet you all come to me for hope? How dare you!"
For four minutes, Thunberg held the room in thrall as she chastised leaders for talking about "money and fairy tales of eternal economic growth" while people suffer.
"People are dying. Entire ecosystems are collapsing," Thunberg said.
Thunberg has been thinking about climate change — and the lack of action to curb it — since age 8, when she first learned about the problem. She has said she didn't understand why adults weren't working to mitigate its effects.
By age 11, she said, she became depressed by the seemingly impossible task of saving the planet.
In May 2018, Thunberg won a climate-change essay competition for the Swedish newspaper Svenska Dagbladet. It was the genesis of her activism career. She started the School Strike for Climate effort three months later, and launched her first protest three months after that.
In an interview with BBC journalist Nick Robinson, Thunberg said that "being different is a gift." If she didn't have Asperger's, Thunberg added, she wouldn't have become such a passionate climate activist.
Thunberg has also tweeted about her condition, saying that having Asperger's is a "superpower."
In December, Thunberg spoke at the 2018 United Nations climate change conference in Katowice, Poland.
"This is the biggest crisis humanity has ever faced," she told UN secretary general António Guterres before the conference started. "First we have to realize this and then as fast as possible do something to stop the emissions and try to save what we can save."
Three months later, on March 15, 2019, Thunberg led more than 1 million students around the world to walk out of their Friday classes to protest inaction on climate change.
Young people in more than 123 countries skipped school to demand more robust climate policies and the reduction of greenhouse-gas emissions.
Thunberg spoke at the Stockholm demonstration during that global event. "We have only been born into this world, we are going to have to live with this crisis our whole lives," she said at the time.
"We are not going to accept this. We are striking because we want a future and we are going to carry on," she added,
according to Reuters.
Thunberg was nominated for the Nobel Peace Prize in March.
She "has launched a mass movement which I see as a major contribution to peace," Norwegian Socialist MP Freddy André Øvstegård told the Guardian. "We have proposed Greta Thunberg because if we do nothing to halt climate change it will be the cause of wars, conflict, and refugees."
Thunberg's fame has continued to grow since then. In April, she briefly spoke with Pope Francis during the weekly general audience at the Vatican.
The Pope has made it clear that he strongly supports action to curb climate change.
"Thank you for standing up for the climate and speaking the truth. It means a lot," Thunberg told him.
"God bless you, continue to work, continue. Go along, go ahead," he responded.
A week after that, Thunberg spoke to UK parliament leaders: "Many of you appear concerned that we are wasting valuable lesson time, but I assure you we will go back to school the moment you start listening to science and give us a future. Is that really too much to ask?"
