The effects of climate change in the Mediterranean basin are clearly evident in our country, one of the most affected by all the possible consequences due to its central position and relative proximity to the coast of the entire territory: the persistence of dry seasons, Record summer temperatures and the violence of storms even out of season often make the headlines in newspapers and online publications. negative effects of the increase in temperatures are however different and sometimes less evident: the increase in the average temperature of sea water and the more acidity pushes the decline of local animal species (native) and the spread of those invasive (allochthonous), while the‘sea level rise leads to the disappearance of coastal territory. The naturalistic and social importance of the Mediterranean areas makes these effects particularly critical, because they are able to influence the economie of the countries that overlook it and promote phenomena such as the depopulation of some areas and the mass migration. But what exactly is the situation of our sea today?
What’s happening in the Mediterranean: the variation in average temperatures
To say that the‘Mediterranean area is one of the areas most affected by global warming is not entirely correct: the areas that see increase average temperatures more rapidly are in fact those closest to the poles, such as Siberia. The area has actually warmed more than the global average, by about +1.5 C° compared to the global average of +1° since the pre-industrial era, but this happens to most of the landmasses compared to the “coldest” oceans.
But if we focus on the sea, the The Mediterranean has warmed more than the oceansup to +0.4 °C every 10 years compared to +0.2 °C: this is mainly due to the shallow depth and low recirculation of its waters due to the narrow passages of Gibraltar to the Atlantic and the artificial Suez Canal to the Red Sea and the Indian Ocean.
Other factors make it a special subject to observation: the increase in water temperature, already dangerous for native species, is added to theacidification of water (which absorb part of the CO2 atmospheric, forming carbonic acid H2CO3): a problem felt by species such as corals or molluscswhich struggle to develop shells and protective structures due to the acidic environment.
Particularly critical are the increases in summer temperatures, which added to the high pollution air pollution is a growing health risk for citizens of large cities, from Barcelona and Marseille to Cairo. It is estimated that days with temperatures above 37 °C could double by 2050, going from the current 30 to 60 days a year in tourist or densely populated areas such as Spain, Egypt or Turchia.
Other consequences of warming in the Mediterranean
Many major cities are coastal, and therefore particularly vulnerable to sea level rise: already risen by approximately 5 cm in the last 10 yearsdepending on the trend of emissions, the level could settle between +40 and +120 cm by 2100. Soil loss can cause damage to agriculture, the local economy and cultural heritage, but above all it can cause mass migrations from the most affected and impoverished areas.
The increase in average temperatures also leads to a decrease in precipitationespecially in the warmer months, with the simultaneous occurrence of more intense events locally. Some climate models hypothesize a reduction of -4% of annual precipitation for each degree of atmospheric warming: a worrying scenario especially for the southern and eastern areas of the basin, already characterized by arid climates and inhabited by 3/4 of the Mediterranean population.
Warmer climates are also linked to big fires, favored by the dry seasons, and to the spread of diseases like the West Nile Virus, already present in various areas of Italy.
The risks for the economies bordering the Mediterranean
The economies of the Mediterranean are very linked to tourism and agriculturetwo sectors that could suffer heavy consequences from the changes underway.
As for theagriculturea mix of fewer water resources, less and more violent rainfall and higher temperatures can have a strong impact on some crops: an example of this is screwan important product for the economies of Spain and Italy (11 and 16% of revenues from the agricultural sector) and fundamental for the French economy (36% of revenues). Grapes are particularly sensitive to climatic and water stress, as well as intense rainfall, and for this reason some varieties may no longer be suitable for cultivation in the areas historically used, such as Bordeaux or the Langhe.
As for the tourismthe Mediterranean area welcomes about 30% of world tourism every year, mainly in the summer months: high temperatures could discourage the influx, while the need to respond to peaks in water demand during the driest months already puts the water systems of the most popular locations into crisis. Even the air quality in large tourist cities it can suffer from increased traffic, precisely in the months when the heat already puts the most vulnerable people, such as the elderly, in difficulty.
The negative effects can be addressed with appropriate countermeasures, from a more careful management of freshwater reserves at the maintenance of forest areas to avoid the increasingly frequent summer fires: only time will tell if, finally, the institutions will be able to follow the right paths and help our countries to face the consequences of global warming.
