Thunberg is 16 but looks 12. She usually wears her light brown hair pulled into two braids, parted in the middle. She has Asperger’s syndrome, which means she doesn’t operate on the same emotional register as many of the people she meets. She dislikes crowds; ignores small talk; and speaks in direct, uncomplicated sentences. She cannot be flattered or distracted. She is not impressed by other people’s celebrity, nor does she seem to have interest in her own growing fame. But these very qualities have helped make her a global sensation. Where others smile to cut the tension, Thunberg is withering. Where others speak the language of hope, Thunberg repeats the unassailable science: Oceans will rise. Cities will flood. Millions of people will suffer.