A few years ago, a group of teenagers in Washington state took on one of our most perplexing problems with a novel strategy: They sued the state government for failing to safeguard the climate for future generations. The tactic was new, the plaintiffs were young, and yet, they won. A superior court judge ruled in their favor in 2016. But then nothing much happened. Now they’re trying again, this time suing the federal government. Seventeen year-old Aji Piper has become one of the faces of this