“The oceans are entering uncharted territory.” That’s how meteorologist JJ González Alemán warned about the record sea water temperature measured by satellites on April 8. The ocean average rose to 21ºC, surpassing the previous record, set just seven years ago, in 2016.
Mediterranean suffers marine heat wave in mid-winter
It is the warmest sea water since there are satellite measurements, that is, at least in the last 45 years. The mix of global warming caused by greenhouse gases and the end of the La Niña phenomenon – which cools the waters of the equatorial Pacific – made the records jump.
“La Niña has been camouflaging global warming in recent years,” explains the spokesman for the State Meteorological Agency, Rubén del Campo. La Niña is a phenomenon of atmospheric interactions in the Pacific Ocean that causes a vast amount of water in a huge expanse of sea to be colder than normal.
“And that lowers the average temperature, not just of the oceans, but of the entire planet,” says Del Campo. “Camouflages the elevation that would match by the level of emission and accumulation of greenhouse gases in the atmosphere”.
In other words, as the gaseous crust created by the release of CO2 grew and trapped heat, La Niña cooled the surface of the Pacific. And this girl was also unusually prolonged: she strung together episodes for three years. However, this phenomenon is over. The same National Office of Oceanic and Atmospheric Administration (NOAA) considered in early March that La Niña had come to an end.
Once completed, Earth is in a transitional phase to the reverse situation. El Niño is brewing, which is warming the water. Therefore, this month of April there was no compensation and the effects of climate change are noticeable without this cushion.
“The ocean accumulates a large amount of heat and, although it warms up more slowly than the continents –because it costs more to heat a volume of water–, it is clear that the temperature of the seas is rising”, underlines the meteorologist.
The amount of heat that to swallow the sea every year goes from record to record. In 2022, the highest value of the entire historical series was measured, which surpassed the previous record of 2021, which, in turn, beat the peak of 2020. The values of 2019 and 2017 are next on the list. Scientists dedicated to these measurements have shown that the trend “is so continuous and robust that a record is set every year”.
“Forecasts indicate that El Niño could arrive after the summer” –informs Rubén del Campo–. “And, of course, if you have all that warmer-than-normal ocean mass, what you expect is the whole to be well above average, and on top of that, that large amount of warm water over a large area is going to push the temperature above average. the average of the planet.
The Mediterranean oven
In Spain, last year it was already an oven for the Mediterranean. In summer, it unleashed “unprecedented” waves of marine heat. “In the Balearic Sea it reached 30ºC in the water”, recalls the spokesman for Aemet. All regions of the western Mediterranean have experienced extreme events.
But with the passing of summer and the arrival of fall and winter, the heat has not subsided. The Mediterranean experienced heat waves in mid-January. The same area of the Balearic Islands had more than 230 days of heat waves, an unprecedented number, according to SOCIB researcher Mélanie Juza, told elDiario.es.
Warming seas is not just a matter of warm water. Temperature beyond limits causes deaths in marine species that cannot adapt or flee and influences the chain of ecosystems that drive much of the human diet.
In addition, some superheated waters feed coastal storms, cold spells and hurricanes: the accumulated heat is energy that, later, if the climatic conditions are favourable, is returned in the form of supercharged storms and winds.
March has been a very hot and very dry month in Spain. The month started with low temperatures, but since then it has been reinforcing the trend of a warmer world. In the end, it was the second warmest March of the 21st century and the third in the historical series (since 1961). At the same time, there was not much rain. The accumulation of precipitation was 21 mm for the peninsula, 7.8 in the Balearic Islands and 4 mm in the Canary Islands. They are the second worst data since 2000 and the sixth since 1961.
In fact, the rains barely reached a third of the expected average for this time of year. “The situation of meteorological drought continues throughout Spain, both for the indicators of the last 12 months and for those of the last 36 months, which means that the long-lasting drought that began at the end of December 2022 persists”, Aemet warned .