Sea surface temperatures (SSTs) reached a record high on March 16, alarming many meteorologists and climate scientists.
According to an analysis by the National Oceanic and Atmospheric Administration (NOAA), The previous record was set in 2016 after an El Niño: this would be more normal as SSTs across the central Pacific are warmer than average and therefore have time to build warmth at the ocean surface.
The March 16 temperature reading is particularly surprising as it occurred after three years of La Niña, where SST anomalies across the central and eastern Pacific tend to be cooler than normal.
The Guardian is reporting that according to NOAA, this means a particularly intense El Niño year or a long period of Pacific Ocean warming is no longer necessary to achieve record-high global SSTs.
The data suggests, at least, that the planet, already beset with extreme warmth, is entering an expected stretch of accelerating heat.
The ocean data comes from a network of buoys, ships, and satellites from which the National Oceanic and Atmospheric Administration collect daily data on the first few meters of ocean depth. The database — known as the NOAA 1/4° Daily Optimum Interpolation Sea Surface Temperature — shows a steady warming trend in sea surface water since the 1980s, with each of the past several years of data ranking well above all older data.
And it looks like 2023 is on pace at least to be yet another year among the warmest on record for the oceans, reports the Washington Post.
“Global sea surface temperatures just reached uncharted territory in modern records and likely much longer,” Mika Rantanen, a researcher at the Finnish Meteorological Institute, wrote on Twitter.
What does all this mean?
Sea surface temperatures are predicted to rise further, at least in the Pacific Ocean, as forecast models suggest El Niño is more likely than not by late summer or early fall. Keep in mind that El nino is associated with higher-than-average sea surface temperatures in the equatorial Pacific.
And El nino tends to accelerate the rise in global temperatures because those warm Pacific waters translate to increased evaporation, which leads to increased cloud cover, which blocks sunlight from reaching Earth’s surface and encourages the trapping of heat in the atmosphere.
The recent trend of rising ocean temperature is “probably the beginning of” a transition to El Niño from the relative cooling influence of La Niña, said Gavin Schmidt, a climatologist and the director of the NASA Goddard Institute for Space Studies
But Boyin Huang, a NOAA oceanographer who focuses on sea surface temperature analysis, said that even if El Niño brings warmer Pacific waters, other oceans can counterbalance that trend. That means it’s too early to draw any conclusions about record sea surface warmth.
“I wouldn’t necessarily expect that this means 2023 will be a record-breaking year,” Schmidt said, although he added that it will “obviously be in the top 10” for sea surface warmth.
If “a fully-fledged El Niño” arrives this year, however, climate scientists expect that a record-setting 2024 could follow.
