Chris Mooney is a Pulitzer Prize-winning journalist and a CNN Climate contributor. He is currently a professor of practice in the Environmental Institute at the University of Virginia.Bathtubs and pools mislead us about the ocean: Its surface is anything but flat.Seas pile up in some spots, pushed by trade winds or pulled by gravity toward big things like ice sheets. Amid it all, at the western end of large ocean basins, the fastest surface currents — veins of warm water — race toward the poles, causing additional slopes at the surface.AdvertisementAdvertisementAdvertisementAdvertisementThe ocean is uneven to begin with, and its unevenness is also changing. Maps of recent changes show intricate patterns of watery hills and valleys, but also call attention to one extraordinary location. Off the coast of Japan, one region of the ocean has been rising by nearly an inch every year, right next to another where it has been falling even faster.It’s the fingerprint of one of those surface currents changing its location, an event that has had dramatic repercussions. The Kuroshio, or “Black Current,” is one of the largest streams of water anywhere in the world, and its recent movement has triggered record-warm ocean temperatures and upended fisheries, an indelible staple of Japanese culture. Scientists say the warm waters have even amplified heatwaves on land and driven extreme rainfall.And while there are signs some of the changes are now waning, fishing communities say they aren’t yet back to normal. Meanwhile, scientists worry it could be a sign of more volatility to come.The position of the current could keep fluctuating, said Bo Qiu, a le …
