She is the voice of a generation, of young people who are calling on their leaders to do more and do better.
Students have taken to the streets across the globe in the hundreds of thousands for a second wave of worldwide protests demanding swift action on climate change.
The protests were inspired by Swedish teenager Greta Thunberg, who spoke to world leaders this week at a United Nations summit in New York.
Friday's rallies kicked off in New Zealand, where young people marched on parliament in Wellington, holding one of the largest protests ever held there.
Schoolchildren
Organisers in the capital were forced to change their security plans to accommodate the crowds, while thousands more marched in Auckland and other parts of the country.
On the other side of the planet, more than 100,000 rallied in Italy's capital Rome, where protesters held up signs with slogans such as "Change the system, not the climate" or just the word "Future".
Marches took place in about 180 locations across Italy, including the financial hub of Milan where one banner read "How dare you!" - the accusation Greta, 16, levelled at world leaders during her UN speech in New York on Monday.
The Italian Education Ministry said students attending the event would not be penalised for missing school.
Fears about the impact of global warming on the younger generation were expressed by schoolchildren in Dharmsala, India. South Asia depends heavily on water from the Himalayan glaciers that are under threat from climate change.
Movement
In Berlin, activists from the Fridays for Future group braved persistent rain to protest against a package the German government recently agreed for cutting the country's greenhouse gas emissions.
Experts say the proposal falls far short of what is needed if the world's sixth biggest emitter is to meet the goal of the Paris climate accord.
Actor Javier Bardem joined dozens of young people in San Sebastian in one of several early demonstrations and rallies held across Spain on Friday morning, ahead of evening demonstrations in major towns and cities. They are expected to draw big crowds, especially in Madrid and Barcelona.
Bardem was in San Sebastian to promote a documentary he worked on with Greenpeace.
The youth climate movement has drawn criticism from some who accuse the students of overreacting and say they would be better off going to school, but the 16-year-old suggested people like her should take it as a compliment.
Leaders
In an apparent sarcastic jibe at Greta this week following her haranguing of world leaders, US President Donald Trump tweeted: "She seems like a very happy young girl looking forward to a bright and wonderful future. So nice to see!"
On Friday, she told a rally in Montreal: "I don't understand why grown-ups would choose to mock children and teenagers for just communicating and acting on the science when they could do something good instead.
She is the voice of a generation, of young people who are calling on their leaders to do more and do better.
"But I guess they feel like their world view or interests is threatened by us. That we should take as compliment, that we are having so much impact that people want to silence us. We've become too loud for people to handle so people want to silence us."
She earlier met Canadian prime minister Justin Trudeau, who praised her activism on climate change. "She is the voice of a generation, of young people who are calling on their leaders to do more and do better," he said. "And I am listening."
Greta indicated that she expects more, even of leaders who welcome the movement.
Listened
"He (Trudeau) is of course obviously not doing enough, but this is just a huge problem, this is a system that is wrong. My message to all the politicians is the same: just listen and act on the science."
In Wellington, 18-year-old university student Katherine Rivers said it was great to see young people taking action and personal responsibility by marching.
"We need to stop pandering to some of the people who are making money off climate change. The big oil companies, the dairy industry etc," she said. "And make a change for the future of these kids that are here."
While thousands of high school students elected to take time off school to protest, many adults also joined the marches. One of them was 83-year-old grandmother-of-three Violet McIntosh, who said: "It's not my future we're thinking about, adding that it was time politicians listened to young people like Greta.
Emissions
In the Netherlands, where thousands joined a protest in The Hague, some participants acknowledged that getting politicians to take action against global warming is only part of the story.
"It's also about then leading sustainable lives and making changes to make your life more sustainable," said Utrecht University student Beth Meadows.
German government spokesman Steffen Seibert said part of the government's plan is to encourage citizens to shift their behaviour.
"People, and businesses too, know that over the coming years, step by step, behaviour that harms the climate (and) causes a lot of emissions will have a higher price than before," he told reporters in Berlin.
This Author
Frank Jordans and Giada Zampano are reporters with Associated Press.