Scientists at the University of Washington were studying records of lightning strikes when they made a shocking discovery. Lightning occurs over cargo ship routes twice as often as it does over the surrounding ocean. Why? The ships aren’t attracting the lightning. They’re creating it!
Lightning forms when moisture latches onto particles, such as dust, creating ice crystals. When these crystals collide inside a cloud, they build up electric charges. Cargo ships release exhaust particles into the air. That leads to more ice crystals—and more lightning! “It’s a flashy example of how humans impact weather,” says study leader Joel Thornton.