An estimated 115 million hectares or 12% of Europe’s total land area are subject to water erosion, and 42 million hectares are affected by wind erosion. An estimated 45% of European soils have low organic matter content, principally in Southern Europe but also in areas of France, the UK and Germany (10). Soil degradation is already intense in parts of the Mediterranean and central-eastern Europe and, together with prolonged drought periods and fires, is already contributing to an increased risk of desertification (11).
Climatic conditions make the Mediterranean region one of the areas most severely affected by land degradation. 12 of the 27 European Union Member States declared themselves as affected countries under the 1992 United Nation Convention on Combating Desertification (UNCCD): in the Mediterranean: Cyprus, Greece, Italy, Malta, Portugal, Slovenia and Spain and in central and eastern Europe: Hungary, Latvia, Slovak Republic, Bulgaria and Romania (9).
Desertification is considered one of the most serious problems facing the Mediterranean region today. The area affected extends across northern Africa into the Near East and across large parts of Europe, including Greece, southern Italy, Sicily, Corsica, and the Iberian Peninsula (1).
Much desertification is attributed to human activities going back over millennia. Human impacts arise from overstocking, over-cultivation and deforestation and, to a lesser degree, irrigation and urbanisation. The potential for desertification is still further enhanced through the direct effects of climate change on erosion, soil quality, salinisation and fire hazard (2).
Key processes include the following (3):
- As soils dry they become more susceptible to wind erosion, especially where there is no vegetation cover or the area is cultivated - this could ultimately generate “dust bowl” conditions in some areas. The hazard of water erosion would also be made worse by any accompanying increase in rainfall intensity.
- Higher temperatures could result in a reduction in soil fertility due to higher rates of decomposition and losses of organic matter, and could affect nutrient cycling.
- A general decrease in precipitation or increase in evaporation will cause an increase in the area affected by saline conditions. Spain and Italy, in particular, could experience an increase in the area affected by low permeability, shrinking and swelling and waterlogging. Coastal areas could be more directly affected by salinisation due to the increased penetration of salt water into the groundwater.
- Increasing temperatures and drier conditions could give rise to more forest fires, although the extent to which land degradation results will vary.
There could also be important feedback effects. For example, a reduction in surface moisture or vegetative cover would increase temperatures and reduce rainfall as less energy is used in evapo-transipiration and less water is recycled. Where vegetation cover is lost completely, soil surfaces become sealed and encrusted, reducing water intake and resulting in a still drier environment (4).
Lately, an ever increasing area worldwide is being threatened by desertification, and an even wider one by soil degradation, resulting in the inability of the earth to provide plants and animals with water and nutritive components for them to grow and survive. The international concern has led to the ratification and entry into force of the Framework Convention of the United Nations for Combating Desertification (CCD). Greece has ratified CCD and has prepared a National Action Plan for Combating Desertification (2001) that addresses the urgent need to combat a discernable desertification trend in 35% of the land as well as to prevent on the onset of desertification in an additional 60% of the country’s area (5).
Climate change is expected to affect the desertification process by increasing the intensity of rainfall, which will accentuate water loss due to run-off and erosion; by increasing evapotranspiration, causing soil salinization; by increasing aridity, which will contribute to reducing concentrations of organic matter in the soil; and by increasing droughts, which will jeopardize many anthropic activities (6).
It is, however, impossible to quantify the combined impact of climate change on desertification. Much will depend not just on the climate change but also of coincident pressures arising from other human activities and the effectiveness of responses to the problem of desertification in general (2).
Poorer infiltration due to soil degradation would reduce aquifer recharge, while reservoirs could be seriously affected by an increase in sedimentation due to erosion. Such sedimentation problems are already anticipated in the Apollakia reservoir in Rhodes (7).
The National Action Plan for Combating Desertification (2001) sets as an objective to combat efficiently the desertification trends in the 35% of the whole Greek territory that is under direct threat and to prevent the desertification process elsewhere.The National Action Plan includes a critical analysis and assessment of the factors and processes that control desertification pressures in Greece as well as general and sector-specific measures.
The main issues in relation to agriculture are erosion of soils and drought problems. Means of addressing them include (5):
- Land Use Planning under sustainability criteria to protect soils from erosion by establishing clear criteria for inclusion of agricultural land, in planning scheme, by appropriate selection of anti-erosion measures and by improving cultivating techniques;
- Covering of land with crop residues, rocks and chemical amendments, (thus reducing the danger of erosion and simultaneously conserving the moisture of the soil) to combat drought and improve ground water conservation.
In Forestry, measures to reduce the frequency and decrease the spread of forest fires are under consideration. These measures include (5):
- Introduction of less flammable plants;
- Thinning, clearing and maintenance of forest structure;
- Ground cover clearing, thinning, disbudding, appropriate settlement or removal of residues and possibly, implementation of controlled grazing;
- Forest fire detection systems to facilitate quick response.
- In addition, measures to counter after-fire impacts and avoid soil erosion have been adopted which include prohibition of grazing in burned lands and soil support to allow for natural regeneration by not clearing burned trees and bushes or by planting appropriate trees, bushes and plants where rapid natural coverage of the ground is not ensured.
In the water resources sector, the suggested measures for water conservation are of particular interest as water shortage in a number of areas in now endemic. The rational management of water resources is important to provide security of supply to address a variety of needs, but also to protect the quality of aquifers and other groundwater reserves. The measures concern (5):
- Reduction of water loss through the improvement of irrigation efficiency (restoration of the networks structure, implementation of integrated management systems of irrigation water, recycling and reuse of water). It is expected that with the implementation of these measures the conservation achieved will vary from 10% to 50% of current use;
- Reduction of water losses and demand in urban and industrial use. The suggested measures are the upgrading of piping networks for the reduction of leaks and rapid leak tracing and restoration of the network damages, as well as the introduction of incentives for the construction of private tanks and collection of rain water;
- Increase of water supply through funding of programs for water recycling and reuse, studies for the risks associated with water shortage in threatening areas, restraint and storage of surface runoff water, transfer of surface water to areas threatened by desertification, management of forests ecosystems so as to limit rainwater losses through surface flow and implementation of systems for artificial concentration of ground water, re-injection of water surplus and replenishment of its reserves.
Besides, socio-economic measures are taken.Main objectives pursued are among others the sustainability in agricultural production and the protection of agricultural population through the supply of technical and information support to farmers, training and support of new farmers, implementation of the LEADER Community Initiative that supports farmers etc. (8).
The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Greece.
- UNEP (1992); Imeson and Emmer (1992), both in: Karas (2000)
- Karas (2000)
- Rosenzweig and Hillel (1993); Imeson and Emmer (1996), both in: Karas (2000)
- Bullock and Le Houérou (1996), in: Karas (2000)
- Hellenic Republic, Ministry for the Environment, Physical Planning and Public Works of Greece (2002)
- WHO (2007)
- Perissoratis et al. (1996), in: Karas (2000)
- Hellenic Republic, Ministry for the Environment, Physical Planning and Public Works of Greece (2006)
- EEA, JRC and WHO (2008)
- European Commission (DG Environment) (2007)
- IPCC (2014)