Sea temperatures around the Fiji Islands in the southwestern Pacific Ocean have reached their highest levels in the last 600 years. According to a study published in Science Advances, the ocean hasn't been this warm in centuries.
The findings provide "further evidence of unprecedented warming in the western Pacific," said researchers at Johannes Gutenberg University Mainz (JGU) in Germany, who participated in the study.
Peering into the climatic past was made possible thanks to the boulder coral (Diploastrea heliopora), which can live for a very long time and grows an average of 3-6 millimeters per year. According to JGU, climate changes of past centuries are stored in the skeletons of such corals.
In particular, researchers studied a two-meter-long coral core, paying special attention to the ratio of strontium to calcium.The age of each layer was determined using the uranium-thorium dating method.
Essentially, scientists look at how much the contained uranium isotopes have undergone radioactive decay and transformed into thorium, which allows them to infer the age.
An assessment of coral data from 1370 to 1997, supplemented by 26 years of water temperature measurements, showed that 2022 was the warmest year in the Pacific region since 1370.
