Climate factors behind record-breaking ocean temperatures in 2023

Map of recent marine heat. Credit: NOAA

A new study describes the confluence of factors behind the 2023 record-high global sea surface temperatures. This work advances efforts to predict and prepare for marine heatwaves, which pose severe risks to marine ecosystems, coastal communities, and global weather patterns. In 2023, global sea surface temperatures (SSTs) reached unprecedented levels, setting multiple records from March through August. NOAA’s Daily Optimum Interpolation Sea Surface Temperature (DOISST) data highlights a link between these record-high SSTs and widespread marine heatwaves. In the new study, published in Geophysical Research Letters, scientists discovered that these extreme conditions were due to a combination of long-term global warming, a natural climate pattern called the Pacific-Atlantic-Arctic (PAA) mode, and the transition from cooler La Niña conditions to warmer El Niño conditions.