During El Niño, a swath of ocean stretching 6,000 miles (about 10,000 kilometers) westward off the coast of Ecuador warms for months on end, typically by 2 to 4 degrees Fahrenheit (about 1 to 2 degrees Celsius). A few degrees may not seem like much, but in that part of the world, it’s more than enough to completely reorganize wind, rainfall and temperature patterns all over the planet. White corals indicate bleaching from heat stress. Marine heat waves can trigger coral bleaching. Dillon Amaya is a climate scientist who studies the oceans. After three years of La Niña, he advises that it’s time to start preparing for what El Niño may have in store.