A wake-up call from the 2023 marine heatwaves

The marine heatwaves of 2023 , which were unprecedented in intensity, duration and geographic extent , may have sounded an alarm bell: according to the study published in the journal Science, they may have marked a fundamental shift in the dynamics involving the ocean and atmosphere, indicating that the Earth's climate is nearing a tipping point .

The research was led by the Oriental Institute of Technology in Ningbo, China. Marine heatwaves are intense and prolonged episodes of unusually high ocean temperatures, which pose a serious threat to marine ecosystems . It is now widely recognized that human-induced climate change is leading to a rapid increase in the frequency and intensity of these events, but the mechanisms behind them remain incompletely understood .

To shed light on the issue, researchers led by Tianyun Dong reanalyzed data for 2023, also using satellite observations . The results show that heatwaves set new records that year, lasting four times longer than the historical average and affecting 96% of the global ocean surface .

For example, in the North Atlantic the heat wave lasted 525 days, in the Southwest Pacific it reached a vast extent, and in the Eastern Pacific temperatures reached peaks of 1.63 degrees above average . The analysis also allowed us to identify several factors that contributed to the formation and persistence of these events: increased solar radiation due to reduced cloud cover , weaker winds , and anomalies recorded in ocean currents .