NEW YORK/SHENYANG, China (Reuters) - A keen reader of graphic novels, nine-year-old Zayne Cowie has a bookshelf laden with tales of the struggles of imaginary superheroes. Now, a real-life role model has inspired him to join a battle for his own planet's future.

Kept awake some nights by fears that rising seas will devastate his native Brooklyn, Cowie came across a news story about Greta Thunberg, a Swedish teen who was walking out of class on Fridays to protest government inaction over climate change.