This story was originally published by The Guardian and is reproduced here as part of the Climate Desk collaboration. Greta Thunberg cut a frail and lonely figure when she started a school strike for the climate outside the Swedish parliament building last August. Her parents tried to dissuade her. Classmates declined to join. Passersby expressed pity and bemusement at the sight of the then unknown 15-year-old sitting on the cobblestones with a hand-painted banner.