At age 8, Greta Thunberg, who lives in Stockholm, Sweden, learned about climate change. By age 11, she had fallen into a deep depression because of the lack of global action to solve the climate crisis. A doctor diagnosed her with obsessive compulsive disorder (OCD), selective mute syndrome, and Asperger’s syndrome, which means she is on the autism spectrum. Being autistic, she said in a TEDx talk, means she sees the world in “black and white.” And for her, acting on climate change is a black and white issue: “We must stop carbon emissions from fossil fuels. We have to change.”

Beginning at age 15, Thunberg started channeling her frustration into being a dedicated climate activist, sitting in front of Sweden’s National Legislature every day, during school hours, demanding the Swedish government reduce carbon emissions by at least 15 percent each year. Thunberg decided on such a radical move…