More than 90% of the excess heat trapped by greenhouse gas emissions is absorbed in the oceans. The records, starting in 1958, show an inexorable rise in ocean temperature, with an acceleration in warming after 1990.
Sea surface temperatures are a major influence on the world’s weather. Hotter oceans help supercharge extreme weather, leading to more intense hurricanes and typhoons and more moisture in the air, which brings more intense rains and flooding. Warmer water also expands, pushing up sea levels and endangering coastal cities.
Last year is expected to be the fourth or fifth hottest recorded for surface air temperatures when the final data is collated. During 2022, we saw the third La Niña event in a row, which is the cooler phase of an irregular climate cycle centred on the Pacific that affects global weather patterns. When El Niño returns, global air temperatures will be boosted even higher.