Across the world, people will gather for a youth-led climate strike on Friday, Sept. 20, in what climate activists hope to be their biggest mobilization yet. West Marin is sending its own coalition of young activists to San Francisco to join in: Claire Hutkins Seda, a board member of the Environmental Action Committee, has organized local youth and allies who will bus to the city. The group, called West Marin Loves Earth, held an art…