In 2023, unprecedented marine heatwaves affected 96% of the ocean surface, potentially pushing the world's oceans into a new, hotter state with serious consequences for climate regulation, marine life, and weather patterns, driven by factors like reduced cloud cover and weaker winds, raising concerns about a fundamental shift in ocean dynamics and the need for urgent research and mitigation efforts.
Researchers have identified localized ocean processes during the 2015-16 El Niño that provided much-needed sustenance to the coral reefs on the Central Pacific island of Palmyra, allowing them not only to survive, but to thrive. The eastward-flowing North Equatorial Counter Current, which hits Palmyra's western shores, was significantly strengthened during the 2015-16 El Niño, driving an upward movement of cooler plankton-rich waters to the island's coral reefs. Identifying coral reefs that have a greater chance of survival during extreme events is critical to understanding the future of coral reef ecosystems.
Scientists at NOAA have found evidence of marine heatwaves at the bottom of the ocean, which last longer, can cause more drastic heating, and sometimes occur with little or no evidence of warming at the surface. The world’s oceans are responsible for absorbing about 90 percent of the excess heat generated by man-made carbon emissions, and as such, it’s warming faster than the planet average, increasing in temperature by about 1.5°C (2.7°F) over the past century – with marine heatwaves becoming around 50 percent more frequent in the last decade alone. Increased temperatures at the bottom of the ocean have been linked to a whole host of ecological problems, and with these new data collection methods, the researchers hope to develop real-time monitoring capabilities that can alert marine resource managers to deep ocean conditions.
