In 25 years, the average surface temperature of the Mediterranean has risen by 1°C. The Mediterranean is getting warmer, not just at the surface. Even the deeper layers, down to 800 meters, show signs of overheating.
This is what emerges from the 100 campaigns conducted by Enea and INGV since 1999 in the Ligurian and Tyrrhenian Seas, during which around 3,000 probes were used to collect data.
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Mediterranean Getting Hotter, Peak in September 2023
What does the “thermal snapshot” of the Mediterranean reveal? The overall data shows that in a quarter of a century, the seas around Italy have warmed by approximately 1°C. The warming of the Mediterranean has not followed a linear trend. Between 2013 and 2016, the temperature increase exceeded 0.4°C. Then, there was a slight decrease. This phase was followed by a new period of warming, starting in 2021 and peaking in September 2023.
To induce the temperature increase measured in the Tyrrhenian Sea between 2015 and 2023 in the layer between 200 and 800 meters, Enea highlights that the amount of energy required would be tens of times the annual electricity consumption of Italy.
And Deeper?
The probes launched during the campaigns have confirmed that the average temperature increase also affects deeper layers. Between 100 and 450 meters, the increase is 0.4–0.6°C, while in the 450–800 meter range, it is 0.3–0.5°C.
The “Warm” Genoa-Palermo Route
The campaigns focused on the Ligurian and Tyrrhenian Seas, measuring water column temperatures up to 800 meters along the same routes. These are the routes followed by GNV ferries on the Genoa-Palermo route. The company, part of the MSC Group, collaborated with Enea and INGV.
“The historical temperature data series along the same route is crucial for climate studies because it allows us to assess the temporal evolution, highlighting possible variations, and thus understand whether there has been warming or cooling along the water column in the monitored area,” explain Enea researchers.
The researchers embark on GNV ferries, which take about 20 hours to travel the route, releasing a probe approximately every 30 minutes. These are expendable bathythermograph (XBT) probes. In the first campaigns, probes measured depths up to 450 meters; later, probes were used that could measure depths of up to about 800-850 meters. Today, four campaigns are conducted each year.