Climate change in the Mediterranean region presents an unusual case: although it fits the trend of globally rising temperatures, it stands as a notable exception to the anticipated pattern of overall greater precipitation levels. In other words, countries around the Mediterranean are expected to become increasingly hot and dry, with severe repercussions for human safety and the environment, terrestrial and marine alike. Amplified risks of natural disasters, increased water stress, and a steady decline of natural biodiversity represent some of the most immediate effects of climate change in the Mediterranean. A region already under great strain, the Mediterranean basin has been described as a ‘climate change hot-spot’, requiring immediate attention and well-coordinated action in response.
The Mediterranean region is warming 20% faster than the global average – an alarming rate which could well mean that some of the warmest summers of the recent past might prove cooler than those to come [1].
With a mean temperature over 1.5°C higher than pre-industrial levels (an increase roughly 0.4°C greater than the equivalent global value), the Mediterranean region is at the maximum global threshold set by the COP21 Paris Agreement to mitigate climate change [2].
On every side of the Mediterranean temperatures are on the rise, with the increase being particularly notable in the summer temperatures of Spain, Lebanon, and Tunisia, all experiencing a difference greater than +1.7°C during 1991-2020 as compared to the period 1901-1930 [3].
Projections for the future vary depending on different climate scenarios, but general consensus points to a rise from 2 to 6°C degrees in the Mediterranean region by the end of the century [4].
Heatwaves & Wildfires
It has been argued that wildfires and climate change perpetuate a positive-feedback mechanism, whereby rising temperatures lead to longer and more severe heatwaves; these in turn condition the region for the outbreak of wildfires; and as these blaze, they release polluting greenhouse gases into the atmosphere, which drive further climate change, feeding an endless, self-perpetuating cycle [5].
According to the Copernicus Atmosphere Monitoring Service (CAMS), global wildfires in 2022 released about 1,455 megatons of carbon emissions [6]. The July 2023 wildfires of Greece alone emitted approximately 3.5 million tons of carbon dioxide [7]. The impact of wildfires is devastating for the environment (including natural biodiversity), and for human safety: it is estimated that over 120,000 people were affected by the 2023 summer wildfires in Greece, Italy, Algeria and Tunisia; and a total of 135,000 hectares (1,350 square kilometres) were burnt in the same regions [7]. Greece was exceptionally hard-hit, with its most severe wildfire, located in the northeast, burning over 94,000 hectares of land [8]. Moreover, to meet the threat, the largest ever evacuation to take place in Greece due to climate-related emergencies was undertaken with 30,000 people having to leave their homes on the islands of Rhodes, Evia, and Corfu [9].
Declining precipitation & Water scarcity
The East Mediterranean and the Middle East (EMME) has been identified as a region particularly vulnerable to the problem of water scarcity. Projected rainfall patterns are the principal reason for this: compared to the period from 1961 to 1990, annual precipitation is expected to decline by 5-25% between 2040-2069 and by 5-30% in the years 2070-2099. Steadily growing population numbers further exacerbate the problem, placing yet more strain on available resources with significant repercussions for human safety, agricultural production and general economic stability [1]. A study combining precipitation estimates with the UN’s population projections for the years 2040-2069 revealed that per capita water can be expected to reduce by almost 50% in Syria and by 67% in Cyprus and Jordan [1]. The vulnerability of the Mediterranean region is highlighted by assessments ranking water-stressed countries around the globe: based on a 2019 dataset by the World Resources Institute, out of the 25 countries identified as facing ‘extremely high’ baseline water stress, 9 (36%) are located in the Mediterranean region, with Cyprus ranked 2nd, Lebanon 4th, and Israel and Egypt 9th and 10th respectively [10].
Floods
Although overall precipitation levels are expected to decline, the threat of floods is not eliminated, as this would presume an even yearly distribution of rainfall.
Instead, it appears that ‘due to changes in the hydrologic cycle, the incidence of extreme precipitation in a warmer climate can possibly increase even in areas where mean precipitation is projected to decrease’ [11]. The torrential rainfalls that devastated countries around the Mediterranean in September 2023 following an exceptionally hot summer seem to empirically support the above assertion. Excessive rainfall resulted in severe floodings, submerging entire households in affected areas, leaving their inhabitants homeless, and causing the death of 6 people in Spain, 7 in Turkey, and 17 in Greece; but it was undoubtedly Libya that suffered the greatest damage, where in the city of Derna alone more than 3,950 casualties were reported. Researchers assessing the interplay between climate change and flood risk have argued that in the cases of Greece and Turkey, ‘human-induced climate change made an event as extreme as the one observed up to 10 times more likely and up to 40% more intense’; the respective values for the case of Libya reached 50 times more likely and 50% more intense [12].
Changing ecosystems
The Mediterranean Sea is remarkable for its biodiversity, hosting between 4 and 18% of the world’s known marine species, despite its surface area comprising a mere 0.8% of the global oceanic surface [13]. With a record surface temperature of 28.7°C during July [9], the rapidly warming waters are driving a transformation of the Mediterranean marine ecosystem: cold-water species are reducing, even becoming extinct, while warm-water species are becoming increasingly abundant. Indeed, favoured by the warmer aquatic environment, more than 900 non-indigenous species have been recorded in the Mediterranean Sea, most entering from the Red Sea through the Suez Canal. One such example is the Fistularia commersonii: first recorded in the Mediterranean Sea in 2000 near Israel, this fish has since spread across eastern and central Mediterranean coasts, reaching as far as the Strait of Gibraltar [14]. Regarded as one of the most successful invasive species to enter the Mediterranean, Fistularia commersonii preys upon commercially valuable fish like the bogue (Boops boops) or the red mullet (Mullus barbatus), raising concerns over food web dynamics and overall ecosystem stability [14]. Although the presence of non-native species may temporarily increase biodiversity in the Mediterranean, studies have shown that in the long-term this interferes with the structural balance of native marine populations, disturbing established food web patterns, and potentially jeopardizing ecosystem functioning more broadly [14].
The land around the Mediterranean Sea is also undergoing a steady transformation due to climate change and other human-driven factors like urbanisation and overexploitation of resources. Given the anticipated changes in temperature and precipitation levels, deserts are likely to expand in southern Spain and Portugal, as well as in northern Morocco, Algeria, and Tunisia amongst others [11]. Just as the changing marine habitat drives a shift in native fish composition and distribution, so the transforming terrestrial landscape affects the biodiversity of native terrestrial species. Mediterranean forests comprise only 1.8% of the global forest area; and yet, the region hosts about 290 woody species – more than the total number of woody species in non-Mediterranean Europe [11]. A comprehensive study on the future of terrestrial mammals in the Mediterranean revealed that positive and negative changes could occur, as a transforming habitat would favour some species at the expense of others. For example, Rhinopomatidae (mouse-tailed bats) are projected to thrive under climate change; on the other hand, Talpidae (desmans, moles) and Cervidae (deer) show the heaviest losses in future population estimates. Depending on the climate scenario, up to 16 different species could become extinct – with Sorex arunchi identified as likely to become totally extinct under every climate change scenario examined. For special Protected Areas (PAs) in northern Africa and the Middle East a decrease in biodiversity from 25% to 37% could occur; the respective values for southern Europe range between 29% and 43%, mainly in Spain. As the researchers of the study conclude, ‘a substantial number of Mediterranean mammals will be severely threatened by future climate change’ warning that ‘the extinction risk for many species is going to increase’ [15].
Conclusion
Climate change is driving an all-encompassing transformation of the Mediterranean region. Steadily increasing temperatures and gradually reducing precipitation levels are expected to exacerbate existing vulnerabilities, particularly water stress. Climate change disturbs the natural habitat of many species, causing overall biodiversity levels to decline, and potentially jeopardizing general ecosystem functioning.
In addition to enduring modifications which transform the very baseline of the Mediterranean, climate change acts as a multiplying force which increases the risk and intensity of natural hazards like wildfires and floods. Such extreme phenomena present a direct threat both to human safety and to the environment.
They, however, only represent a fraction of what climate change might lead to. The far-reaching repercussions of climate change are presented in the second part of Climate Change and the Future of the Mediterranean Region, including key challenges for the agricultural and fishing industries, the anticipated effects of climate change on tourism, and the future of cultural heritage located in coastal zones.
References
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[10] S. Kuzma, L. Saccoccia, and M. Chertock, ‘25 Countries, Housing One-quarter of the Population, Face Extremely High Water Stress’, World Research Institute, Aug. 2023, [Online]. Available: https://www.wri.org/insights/highest-water-stressed-countries
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[15] L. Maiorano et al., ‘The future of terrestrial mammals in the Mediterranean basin under climate change’, Philosophical Transactions of the Royal Society B: Biological Sciences, vol. 366, no. 1578, pp. 2681–2692, Sep. 2011.
