NOAA Warns Pacific Ocean Heatwave Will Grow

A marine heatwave is a long period when ocean water is much warmer than usual. The current Pacific event is unusual for its size and how long it has lasted. Scientists say the warm water weakens upwelling, the process that brings cold, nutrient-rich water to the surface. When upwelling slows, small fish and krill swim to deeper, cooler layers. This forces seabirds and other hunters to work much harder for food. Researchers compare today's conditions to "the Blob" of 2014–2018, which killed about one million seabirds. At the same time, El Niño is forming. Forecasters say there is a greater than two-in-three chance of a "strong" or "extreme" El Niño later this year.

Warning signs are already appearing. Scientists walking California beaches have counted dozens of dead seabirds. Brown pelicans left their nests in Mexico and flew north weeks early. A great white shark was recorded for the first time in British Columbia waters. On land, the linked weather pattern brought the warmest winter on record to the western United States. In March, temperatures rose more than 30°F above normal in states like Minnesota and Colorado. With record-low snow, worsening drought, and El Niño coming, scientists fear a serious wildfire season and more damage to fisheries.