The 2023-2024 El Niño led to record-high sea surface temperatures (SST) in the Philippines, peaking at 30.45°C in June 2024. These temperatures exceeded those seen during previous El Niño events, including the 2015-2016 period, according to the University of the Philippines (UP) Marine Science Institute (MSI).
A new study by the UP MSI found that these elevated SSTs continued for three months after El Niño officially ended in May 2024, particularly from June to August 2024.
“Understanding how these extreme events evolve in a warming world is crucial, especially as marine ecosystems are already under stress,” the authors of the study said.
Researchers Rachel Francisco, Dr. Charina Lyn Amedo-Repollo and Chloie Ann Libatog from the Physical Oceanography and Observation Laboratory worked with Dr. Maria Vanessa Baria-Rodriguez of the Interactions of Marine Bionts and Benthic Ecosystems Laboratory to investigate marine heatwaves in the Philippines.
The study, “Evolution of Marine Heatwave in the Philippines During and After the 2023/24 El Niño,” was recently published in the journal IOP Conference Series: Earth and Environmental Science. It used data from the Global OSTIA NRT dataset to examine the spatiotemporal evolution of sea surface temperatures from March 2023 to August 2024. Two groups of marine heatwaves were identified.
The first group occurred from November 2023 to January 2024 in the northwest Philippines. While cooler waters are typically expected from the northeast monsoon (amihan), these winds were insufficient to counteract the heat from El Niño, the study said.
The second, more intense group of marine heatwaves took place from April to August 2024 in both the northwest and northeast Philippines. As El Niño receded, warm winds from the southwest monsoon (habagat) intensified the heat, leading to prolonged marine heatwaves that persisted even after the El Niño event concluded. In both groups, the marine heatwaves originated in the north and progressed southward over time.