Thunberg initiated the school climate strikes and public talks that have made her an internationally renowned climate campaigner in August of 2018. In an interview with Amy Goodman of Democracy Now!, she stated that she conceived the concept of a climate strike after the February 2018 school shootings in the United States prompted numerous students to refuse to return to class. These students from Marjory Stoneman Douglas High School in Parkland, Florida, organized the March for Our Lives in support of stricter gun regulation. In May of 2018, Thunberg won an essay contest on climate change hosted by the Swedish daily Svenska Dagbladet. Partially, she wrote “I want to feel safe. How can I feel safe when I know we are in the greatest crisis in human history?”
Following the publication of her piece, she was approached by Bo Thorén of Fossil Free Dalsland, an organization interested in combating climate change. Thunberg participated in several of their meetings. Thorén suggested at one of them that students may strike for climate change. Thunberg attempted to get other young people to join the strike, but “no one was really interested,” so she ultimately opted to proceed alone.
On August 20, 2018, Thunberg, who had just begun ninth grade, resolved not to attend school until the 2018 Swedish general election on September 9; her protest began following heat waves and wildfires during Sweden’s warmest summer in at least 268 years. Her requests were that the Swedish government cut carbon emissions in accordance with the Paris Agreement, and she demonstrated this by sitting outside the Riksdag during school hours every day for three weeks with the sign Skolstrejk för klimatet (School strike for climate).
Thunberg said her teachers were divided in their views about her missing class to make her point. She says: “As people, they think what I am doing is good, but as teachers, they say I should stop.”