Mediterranean Sea and sea-level rise
The Mediterranean Sea, bordered by Europe, Africa, and Asia, is a semi-enclosed body of water with unique ecological and geographical characteristics. Spanning approximately 2.5 million square kilometers, it plays a crucial role in the climate and economy of the surrounding regions. However, the Mediterranean is facing significant challenges due to climate change, particularly rising sea levels. Between 2000 and 2018, sea levels increased by about 7 centimeters, and projections suggest they may rise by over a meter by 2100, threatening coastal communities and agricultural areas, especially in the vulnerable Nile Delta.
In addition to rising water levels, the Mediterranean region is likely to experience increased temperatures and more intense weather events, including droughts and extreme heat, which could reach as high as 50 degrees Celsius. These changes jeopardize freshwater supplies, exacerbate water shortages, and lead to salinization of arable land. The region's biodiversity is also at risk, with native species threatened by warmer, saltier waters and the introduction of non-native species. As these environmental stresses increase, they may disrupt tourism, a vital economic sector, further complicating the challenges faced by this culturally rich and diverse region.
Subject Terms
Mediterranean Sea and sea-level rise
Definition
Bounded by Africa to the south, Asia to the east, and Europe to the north and west, the Mediterranean Sea is virtually landlocked. It is approximately 2,510,000 square kilometers in area, has an average depth of 1,501 meters, and reaches a maximum depth of 5,092 meters. It is believed that the Mediterranean was created as a result of interactions over millions of years between the Eurasian and African continental plates.
The major source of the Mediterranean’s water is a surface current flowing inward from the Atlantic Ocean at the Strait of Gibraltar in the west. This current increases in salinity as it progresses, eventually sinking in the eastern Mediterranean and reversing course to flow outward along the seabed through the strait. Other important sources of water are the Black Sea (considered by some to be an arm of the Mediterranean) to the northeast, several large rivers (including the Nile), and rainfall. Because of its semi-landlocked nature, the Mediterranean has limited tides, and its high rate of evaporation makes it saltier than the Atlantic. The narrow, human-made Suez Canal links the Mediterranean to the even saltier Red Sea in the southeast.
In general, the Mediterranean region is dry and hot during the summer and wet and cool during the winter. It is positioned between rainy, temperate Central Europe and arid North Africa and is sensitive to variations in these regions’ normal weather patterns.
Significance for Climate Change
Climatologists and meteorologists predict that global warming will have a marked negative effect on the Mediterranean Sea and the countries lying on its shores. Existing problems such as flooding, heat extremes, water shortages, and are likely to grow worse. Studies showed that Mediterranean Sea levels are rising at a significant rate, increasing roughly 7 cm between 2000 and 2018.
Because of global climate disruptions, the level of the Mediterranean Sea may rise by one meter or more by 2100, covering beaches and inundating coastal communities that are home to millions. The low-lying, rapidly eroding Nile Delta, a major crop-growing region in which more than 90 percent of Egypt’s population lived as of 2023, is in particular danger, as up to one-third of the delta could be submerged and saltier water could prevent agricultural activity in the future. Some have suggested that the Mediterranean could grow stagnant, and that the flow of surface water through the Strait of Gibraltar might even reverse. The sea’s resources are already threatened by overfishing, and warmer, saltier water threatens other native species such as corals and sponges, while favoring that have entered the Mediterranean from the Red Sea by way of the Suez Canal.
According to the United Nations’ Intergovernmental Panel on Climate Change (IPCC), annual mean temperatures will probably increase throughout Europe, and the Mediterranean region is expected to experience hotter summers. This increase could have particularly serious consequences along the coast of North Africa. Heatwaves are likely to increase in number and intensity, though not necessarily in length. Extreme high temperatures could rise by as much as 8 degrees Celsius over historic records, with heatwaves of 50 degrees Celsius (122 degrees Fahrenheit) possible. Rising temperatures will probably also result in increasingly intense storms, and although hurricanes rarely touch Europe, a 2007 study suggests that heat-induced atmospheric instability coupled with warmer sea temperatures could lead to tropical storms forming in the Mediterranean.
Annual precipitation is likely to decrease over the Mediterranean region, particularly the southern areas of Portugal, Spain, and France and parts of the Balkans and Turkey. Summers in particular are expected to be drier. Only in the areas dominated by mountain ranges such as the Alps is runoff likely to rise substantially, and those areas may lose a greater proportion of moisture due to higher temperatures. The Italian and French Mediterranean and Balkan coasts may be at higher risk of flooding. Droughts are likely to increase in frequency and severity, especially in the western Mediterranean.
Water usage in the Mediterranean region doubled in the second half of the twentieth century, and lack of water, already a serious problem in many parts of North Africa and the Middle East because of growing populations, is expected to intensify. Rising sea levels will likely result in the salinization of freshwater needed for agriculture and human consumption.
Historically, the lands of the Mediterranean region have suffered from anthropogenic deforestation, and the resulting desertification is likely to spread in many areas. The increase in the number of forest fires forecast by the European Spatial Planning Observation Network in 2006 will add to the severity of the problem and will contribute to a loss of biodiversity. By the 2020s, the annual number of forest fires in the Mediterranean basin had reached twice that of the 1970s.
Under conditions of global warming, death rates in the Mediterranean region from storms, heat stroke, air pollution, lack of water, and even malaria can be expected to rise. Many Mediterranean destinations will likely become too hot for tourists, at least during traditional peak summer months, potentially undermining one of the region’s major sources of revenue.
Bibliography
Conniff, Richard. "The Vanishing Nile: A Great River Faces a Multitude of Threats." Yale E360, 6 Apr. 2018, e360.yale.edu/features/vanishing-nile-a-great-river-faces-a-multitude-of-threats-egypt-dam. Accessed 21 Dec. 2024.
Giorgi, Filippo, and Piero Lionello. “Climate Change Projections for the Mediterranean Region.” Global and Planetary Change 63 (2008): 90-104.
Hughes, J. Donald. The Mediterranean: An Environmental History. Santa Barbara, Calif.: ABC-CLIO, 2005.
Jacob, Daniela, et al. "Climate Impacts in Europe under +1.5°C Global Warming." Earth's Future, vol 6, no. 2, 2018, pp. 264–85. American Geophysical Union, doi:10.1002/2017ef000710. Accessed 21 Dec. 2024.
Marquina Barrio, Antonio, ed. Environmental Challenges in the Mediterranean, 2000-2050. Boston: Kluwer, 2004.
"Staggering Sea-Level Rise in the Mediterranean Sea Revealed by New Study." National Oceanography Centre, 31 Oct. 2022, noc.ac.uk/news/staggering-sea-level-rise-mediterranean-sea-revealed-new-study. Accessed 21 Dec. 2024.
Ulbrich, U., et al. “The Mediterranean Climate Change under Global Warming.” In Mediterranean Climate Variability, edited by Piero Lionello, Paola Malanotte-Rizzoli, and R. Boscolo. Oxford, England: Elsevier, 2006.