Does more than a month that the Mediterranean Sea is immersed in an unprecedented heat wave. The last week of June, the sea thermometers began to mark an increase in surface temperature and, since then, the temperature continues to rise. The records indicate that in these weeks the water has become five to seven degrees warmer than usual for this time of year. In recent days, in addition, extremes of up to 30 degrees have been recorded in some regions: a figure record that, according to several experts consulted by this newspaper, was not expected to be achieved for a few decades.
The heat wave seawater that floods the Mediterranean is being one of the longest and most intense since there are records. The average temperature recorded during the month of July is highest eighth of the last 40 years. If the forecasts are confirmed, and the temperatures also remain this high during the month of August, the extreme and prolonged heat could have devastating consequences for the Mediterranean. Biologists glimpse possible mass mortality episodes of marine species and ecosystems towards the end of summer. Meteorologists, for their part, warn that increases the risk that next fall we have heaviest torrential rain.
Hotspot
The Mediterranean already stands out as one of the hot spots of the climate crisis. The water in this region is heating three times faster than the other oceans of the globe. “From 1980 until now, the temperature of the Mediterranean has increased by 1.1 degrees on average. Just as it happens on land, in the sea too some points are more affected than others but, in general, we see that global warming also affects large parts of the coastline”, explains samira khodayarcoordinator of the Meteorology and Climatology program of the Center for Environmental Studies of the Mediterranean (CEAM).
“Marine heat waves in the Mediterranean are becoming more frequent, extensive and of greater magnitude”
Joaquim Garrabou
While, on the one hand, the average temperature of the waters rises, on the other, an increase in extreme weather episodes is also observed. “Marine heat waves in the Mediterranean are more and more frequent, extensive and of greater magnitude. What were previously exceptional episodes are unfortunately becoming in a new normal“, comments Joaquim Garrabou, researcher at the Institute of Marine Sciences (ICM-CSIC) in Barcelona. The same heat waves that once occurred every 10 years now, with the advancement of the climate crisis, occur continuously. Especially in the last decades.
Mass mortality episodes
The marine heat waveslike the one experienced in recent weeks, are causing an increase in the temperature of the both surface and deep water. In fact, according to the records, temperature increases can be observed up to 50 meters deep. “Temperature extremes and prolonged heat are producing mass mortality episodes in dozens of species and marine ecosystems of the Mediterranean”, says Garrabou, also responsible for the network T-MEDNet on the study of marine heating.
“Temperature extremes and prolonged heat are producing episodes of mass mortality”
A recent study published in the journal ‘Global Change Biology’ highlights that the increase in marine heat waves in the Mediterranean has caused episodes of mass mortality in at least 50 different species. From corals to native sponges, passing through molluscs as iconic as the nacra (now critically endangered). In some cases, extreme heat has affected Between 50% and 80% of individuals of the species most vulnerable to high temperatures.
dowhat will happen now that the Mediterranean records temperature records? According to Garrabou it is still early to take stock. “We will have to wait until the end of summer to see the consequences of this heat wave. From September and October we will begin to see the real impact of the extreme heat of these weeksexplains the marine scientist. “I hope I’m wrong, but there could be more than 90 species affected. And this could be just the tip of the iceberg of much more serious problems”, says the expert.
Risk of cold drop
The rising temperatures in the Mediterraneanbeyond the effect it may have on the waters, it could also affect the next fall weather forecast. Although, according to the experts, the cause-effect relationship is not so direct. Not so immediate. “For an episode of torrential rains to occur, they have to give several conditions. One is the high temperature of the sea, another is the high presence of water vapor in the atmosphere and another is the arrival of a atmospheric instability situation“Khodayar explains.
A clear example to understand this process, explains the scientist, were the torrential rains of 2018. The same ones that caused countless material and human damage in Mallorca. According to an analysis carried out by the Center for Environmental Studies of the Mediterranean, that episode was driven by the conjunction of three factors. In the days leading up to the storm, the water in the Mediterranean warmed up. Water vapor levels rose above normal. And there was a moment of atmospheric instability. The combination of all this was what, finally, triggered torrential rains.
Related news
Will the same thing happen this fall after more than a month of heat wave in the Mediterranean? The high temperatures recorded at the sea surface increase, at least in part, the risk of torrential rain for the next few months. But the final balance is still not clear. “The climate system is complex and it depends on the interaction of many factors“, clarifies Khodayar. Even so, despite this nuance of caution, the expert recalls that, according to countless studies, the advance of the climate crisis exposes us to more and more extreme weather events. Either on land, at sea or in the air.
“It is urgent to propose solutions to protect the health of people, species and ecosystems”
samira khodayar
“The climate crisis confronts us with a big and complex challenge, ranging from the loss of biodiversity to the increase in extreme weather events. We need to roll out concrete plans to adapt to these phenomena and mitigate the effects of this crisis“, claims Garrabou. “It is urgent to understand and raise awareness of the seriousness of the problem and propose solutions to protect the health of people, species and ecosystems. We are going towards a future where this will go to more, not to less”, settles Khodayar.