AECID - Agencia Española de Cooperación Internacional para el Desarrollo

Texto

The Mediterranean, cradle of civilizations, has been the axis around which a significant part of the history of humankind has developed. The “sea at the centre of the Earth” was the first to be explored and, historically, its shores have been the site of important human settlements.

The total population of the countries around the Mediterranean rim in 2000 was almost 430 million, whereas in 1970 it was 280 million, in other words an increase of over 50% over the last thirty years. It is estimated that by 2025 the number of inhabitants of the Mediterranean basin will have reached 520 million. Even though this is a clear sign of the slowing down of population growth in the area, this will still mean an increase in environmental pressure in the immediate future, especially because this rise in population will be mainly concentrated in the countries in the southern and eastern Mediterranean.

At present, some 180 million people live in countries of the northern rim of the Mediterranean, while those in the south and east are home to some 200 million. Taking into account that the population growth rate in developed countries is stable and below 1% per year, and that the countries in the south and east may have corresponding values exceeding 6.5%, it is evident that the latter countries will undergo greatest imbalances in the coming years due to the increasing demographic pressure to which the Mediterranean area will be subjected.

Indeed, the coast surrounding the Mediterranean contains more than 100 cities with a population of 100,000 or more. In most of the countries in the southern and eastern Mediterranean, the most important urban centres are sited in coastal regions, which, moreover, tend to be the most fertile areas. Urban population is growing rapidly and the growth of these cities is frequently ungoverned. High rates of population growth, together with internal flows of population, are creating severe effects on the environment.

It should be noted that population, its flows and its distribution in the territory, constitute the main factor for environmental change in the countries within the Mediterranean Basin, and lead to an intensification of urbanization levels and the modification of land use in general, increased consumption of all types of resources, and the ensuing production of waste.

The important level of human activity in coastal areas is leading to serious pollution problems, caused by the large quantities of industrial and urban waste that are produced, in a sea with a low capacity for self-decontamination and a slow water renewal cycle. The quality problem is further aggravated by the over-exploitation of fishing resources, compounded by the fact that this is a relatively unproductive sea. The Mediterranean is the world’s leading tourist destination. The tourist industry, fundamentally based on a massive occupation of the coastline, has led to dramatic changes in the landscape and to the natural resources of the coasts, with the building of infrastructures, population overload, seasonal pressure, etc.

The Mediterranean is almost entirely enclosed and a relatively small sea. It comprises just 0.7% of the total surface area of the seas and oceans on Earth. It has a maximum depth of 5,100 m off the southern coast of Greece, but in general it is a shallow sea, with an average depth of only 1,500 m. The circumference of the sea measures 46,000 km, with a maximum nautical length and breadth of 4,000 and 850 km, respectively.

The water balance of the Mediterranean is negative: more water evaporates than is contributed by rainfall and by the inflow from rivers. Nevertheless, this water deficit is compensated for by the positive interchange of water entering from the Atlantic via the Strait of Gibraltar, which is 15 km wide and some 300 m deep. Lesser contributions are also received from the Black Sea, via the Bosphorus. In this respect, it should be noted that the water renewal cycle in the Mediterranean is completed approximately once every hundred years.

The Mediterranean climate appears to the west of large continental land masses that are at a latitude of 30-45º north of the equator. This climate is characterized by relatively wet winters and dry summers. Rainfall is scant, and the dry period lasts from three to five months during summer. Over 90% of precipitations take place between September and March; torrential rainfall may occur, especially in autumn. On the other hand, temperatures remain relatively mild both in winter and in summer, with little variation (around 15º) during the year. The land relief, thus, is of decisive importance in the specific type of climate found in each zone.

The geographic location of the Southern Mediterranean, with its low level of rainfall as a result of global atmospheric circulation, and where temperatures are constantly high, creates a north-south aridity gradient which reaches the Sahara desert, with evident problems of desertification in the transition areas.

The relief of the area, together with the large number of islands in the Mediterranean, have shaped a wide variety of landscapes and geomorphological situations throughout the basin. There is a predominance of rugged, inaccessible coastlines, although there are also long stretches of smoothly undulating beaches, mainly related to river courses and their outflow into the sea.

Water is vital in the Mediterranean basin, both for the survival of ecosystems and for human development. However, water resources in the region are fragile and very insufficient; moreover, they are unequally distributed both in the region as a whole and within individual countries.

The per capita availability of water is highly unbalanced between the countries to the North, where water supplies are relatively abundant, and those to the South and East, which are poor or extremely poor as regards access to water resources. On the contrary, demand increases unremittingly, due to population increase and the intensification of human activity, especially because of industry, tourism and agriculture dependent on irrigation. In many countries to the South, water consumption exceeds natural renewal mechanisms, leading to the exhaustion of available resources.

The above mentioned scarcity is often accompanied by low water quality, especially in the South, where water is often highly saline. This situation is aggravated by overpumping in some coastal areas, which has led to phenomena of marine intrusion into the aquifers, and also by salt and nitrate contamination from agricultural practices and from urban areas.

Thus, the Mediterranean basin is characterised by its great heterogeneity, due to wide variations in climate, the diversity in the composition and arrangement of the materials that constitute it and the many different types of land and soil to be found. In consequence, the Mediterranean is the second-richest area in the world in endemic species, after the Andes, providing a native habitat to about 20% of all the vascular plants to be found on Earth, or some 30,000 species, of which 13,000 grow exclusively in countries around the shores of the Mediterranean.

Furthermore, a great variety of reptiles, amphibians and mammals inhabit the area, some of these being in serious danger of extinction. In addition, the waters of the Mediterranean contain 56% of all known marine species, and so this region contains the highest proportion of endemic marine life on the planet, and the second highest number of species, after the tropical seas.