The ocean continues to warm, new record in 2023:here are the risks

The progressive warming of marine waters has direct consequences both on meteorological phenomena (which become more violent) and on marine animal and plant life

ROME – The 'ocean fever' is still rising. In 2023 temperatures increased, setting a new record in water warming, with an increase in heat content, stratification and salinity.This is what emerges from the New Record Ocean temperatures and related climate indicators in 2023 study, published in the journal Advances in Atmospheric Science and conducted by an international team, coordinated by Iap-Cas (Institute of Atmospheric Physics of the Chinese Academy of Sciences) and composed of US scientists from the Ncei-NOAA (National Centers for Environmental Information of the National Oceanic and Atmospheric Administration), New Zealanders, French and, for Italy, by Simona Simoncelli of the National Institute of Geophysics and Volcanology (INGV) and Franco Reseghetti of the National Agency for new technologies, energy and sustainable economic development (ENEA).

In 2023, the temperature of ocean waters, which cover 70% of the planet and absorb about 90% of the heat caused by global warming, increased by a value between 8 (according to NOAA calculation) and 15 (IAP-CAS calculation) ZettaJoule compared to 2022 in the layer between 0 and 2000 meters deep:to give you an idea, one ZettaJoule is equivalent to double the amount of energy that powers the world economy every year.The different results seem to be mainly attributable to the different data quality control procedures and calculation methodologies.

THE WATER ALSO HEATS ON THE SURFACE

In addition to the general warming of the waters, Very strong anomalies were also found in ocean surface temperatures, with unexpected values ​​attributable in this case not only to global warming, but also to the short-term thermal fluctuations of the Pacific Ocean due to the transition of the La Niña and El Niño phenomena, starting from May 2023.

CONSEQUENCES ON WEATHER BUT ALSO ON ANIMAL AND PLANT LIFE IN THE OCEAN

The overall warmer waters produced by the combination of these factors can change weather patterns worldwide.In particular, the variation in atmospheric precipitation and the evaporation of surface waters alter the salinity of the ocean, so salty areas continue to become saltier and areas with fresher water continue to decrease in salinity, with direct consequences on marine life, ocean currents and interactions with the atmosphere.
Less dense, warmer and less salty waters tend to remain at the surface and are unable to transport heat, carbon dioxide and oxygen to deeper waters, with serious consequences for animal and plant life in the ocean.In this case we are talking about “stratified” waters:according to the study just published, in the last year stratification has also increased further compared to 2022.

WARMER OCEAN RESULTS FROM MORE VIOLENT STORMS AND WINDS

Due to warmer ocean waters, excess heat and moisture enter the atmosphere due to the evaporation of surface water, making storms more violent, with rain and stronger winds and, therefore, with a greater risk of flooding, even on Italian territory.

THE MEDITERRANEAN SEA

In this global scenario, the Mediterranean Sea in 2023 confirmed itself as the fastest warming basin among those analyzed in the study, reaching the highest thermal value since the beginning of modern recordings.“In 2023, Ingv and Enea continued, as part of the Macmap project financed by Ingv, to collect data on the temperature of Mediterranean waters on a seasonal basis, in particular Ligurian and Tyrrhenian Seas along the Genoa-Palermo route, thanks to the collaboration with the shipping company Grandi Navi Veloci (Gnv) - explains Simona Simoncelli, Ingv researcher and co-author of the study - The analysis of these temperature data, as well as those collected at 400 meters deep from the Cnr-Ismar buoy in the Sicilian Channel, he indicates starting from 2013 a clear warming in the water layer between 150 and 450 meters deep, which then extended to deeper (up to 700 meters) and more northern waters.In this case between 2013 and 2016 the warming was above 0.4 °C, followed by a slight decrease and a stationary period. Water temperatures have started to increase again since 2021, reaching its record, for the moment, in September 2023."

“Continuing to systematically monitor the seas, specifically the Mediterranean Sea, by measuring the values ​​of some parameters such as temperature, salinity, PH and oxygen, remains the only way to consolidate knowledge on the subject and improve the reliability of the forecasts that at the at the moment they are not as accurate as necessary and desired, even if there is a clear trend of increasing temperatures", adds Franco Reseghetti, Enea researcher and co-author of the study.

“The Mediterranean strongly influences life in the countries bordering it:from agriculture, to fishing, to hydrology, to weather evolution, to the health of populations. Continuing to monitor it is key to helping us learn about the effects of global warming, raise awareness in society of this emergency and stimulate the adoption of necessary adaptation and mitigation measures.We must always keep in mind that due to this phenomenon enormous material damage is recorded every year all over the world, often accompanied by the loss of human lives", conclude the researchers.