Taking the Lid Off

0:00Exploring Science in the Sea. If you put a lid on a pot of boiling water, most of the heat stays inside the pot. But when you take the lid off, a lot of heat escapes, warming the air around the pot. The same thing has been happening in the Pacific Ocean. For several years, La Nina acted as a lid, trapping a lot of heat in the ocean. Then El Nino came along and took the lid off. That released huge amounts of heat into the atmosphere, helping

0:34to produce the hottest year ever recorded. From 2020 to 2023, there was a sequence of La Ninas, periods of especially cool surface waters in the eastern Pacific. They trapped the heat in the deeper ocean. The La Ninas were followed by a moderately strong El Nino, especially warm surface waters. That took the lid off the trapped heat. Research has shown that from July 2023 through June 2024, the average global temperature was about two-thirds of a degree

1:05Fahrenheit higher than during the previous 12 months. That's the largest single-year jump seen so far. Almost all of that rise was driven by the higher ocean surface temperatures produced by the transition from three years of La Nina to El Nino. Not all oceans contributed equally to the increase. Most of the heat came from tropical regions. The tropical Pacific Ocean, the Indian Ocean, and the tropical North Atlantic Ocean accounted for 80 percent of the bump.

1:36In all, they contributed about half a degree Fahrenheit to the average temperature around the entire planet. Science in the Sea is a production of the University of Texas Marine Science Institute and is on the web at scienceinthesea.org. I'm Holly Brawley.