The likely effects of climate change on the water resources of the eastern Mediterranean and Middle East region have been investigated using a high-resolution regional climate model (PRECIS) by comparing precipitation simulations of 2040–2069 and 2070–2099 with 1961–1990 (23). The projected change in internal water resources is assumed to be the same as the projected change in precipitation. According to the analysis of the PRECIS model results, Albania’s water resources will decline by 14%. With its population not expected to grow significantly and being generously endowed with water relative to its population, Albania should not experience significant socioeconomic impacts due to climate change reducing water availability.

Under the reduced surface water flow and increased evaporation, the storage of reservoirs will decrease, and that would affect the energy production by hydro power stations (5).

Because of the reduction of stream flows in the wetlands, the western part of Albania would experience both increasing demands for water and reduced supply of water, which would decrease wetland area (5).

The increase of the extreme events may lead an under designed reservoir or spillway with potential flood risk (5).

Other consequences of expected warming include not only changes in total water amount and levels, but also erosion of riverbeds, and modification of turbidity and sediment load (5).

The likely reduction of water resources would lead to less dilution flow in the stream. It might lead to degraded water quality or increased investments in waste water treatment, especially for the third horizon 2100, where the reduction of the river flow would be very high. Water quality is expected to degrade in Albania, not only due to the expected climate changes, but also due to new industrial and agricultural development. The main hot spots for this problem are the districts of Tirana, Fier, Korçë, Kavajë, Durres, Vlorë, Elbasan and Berat (5).

The ground water supply will be affected by decreased percolation of water, due to decrease in the amount of precipitation and stream flow and as well as losses of soil moisture from increased evapotranspiration. This can lead to the increase of pumping costs (5).

The predicted sea level rise of 20-24 cm by 2050 is not expected to have significant impact on ground water, whereas the sea level rise of 48-61 cm expected by 2100 will cause the increase in the salinity of aquifers especially for the coastal area. This effect will be more significant in Fushe Kuqe and Durresi plain. Fushe Kuqe has very important aquifers, because it supplies drinking water to the northern coastal cities as well as Durresi and Kavaja. The other areas that will be influenced, though less than Fushe Kuqe and Durresi plain, are Velipoja (Zadrima plain in Shkodra city) and Vlora plain (5).

Reduction in ground water supply in combination with the increase of salinity of the ground water supply will bring shortage of adequate quality of drinking water. Moreover, the demand for drinking water and water use for social and economic purposes may be expected to increase because of population growth (5).

In south-eastern Europe annual rainfall and river discharge have already begun to decrease in the past few decades (9).

Water stress will increase over central and southern Europe. The percentage area under high water stress is likely to increase from 19% today to 35% by the 2070s, and the additional number of people affected by the 2070s is expected to be between 16 million and 44 millions. The most affected regions are southern Europe and some parts of central and eastern Europe, where summer flows may be reduced by up to 80%. The hydropower potential of Europe is expected to decline on average by 6% but by 20 to 50% around the Mediterranean by the 2070s(10).

Annual average runoff in southern Europe (south of 47°N) decreases by 0 to 23% up to the 2020s and by 6 to 36% up to the 2070s, for the SRES A2 and B2 scenarios and climate scenarios from two different climate models (10). Summer low flow may decrease by up to 80% in some rivers in southern Europe (11,12). Other studies (1) indicate a decrease in annual average runoff of 20–30 % by the 2050s and of 40–50 % by the 2075s in southeastern Europe.

Climate change must be seen in the context of multi-decadal variability, which will lead to different amounts of water being available over different time periods even in the absence of climate change. … the average standard deviation in 30-year average annual runoff is typically under 6% of the mean, but up to 15% in dry regions (13).

Temperature rise and changing precipitation patterns may also lead to a reduction of groundwater recharge (14) and hence groundwater level. This would be most evident in southeastern Europe. Higher water temperature and low level of runoff, particularly in the summer, could lead to deterioration in water quality (15). Inland waters in southern Europe are likely to have lower volume and increased salinisation (16).

Most studies on water supply and demand conclude that annual water availability would generally increase in northern and northwestern Europe and decrease in southern and southeastern Europe (1). In the agricultural sector, irrigation water requirements would increase mainly in southern and southeastern Europe (17). The risk of drought increases mainly in southern Europe. For southern and eastern Europe the increasing risk from climate change would be amplified by an increase in water withdrawals (18).

Water shortages due to extended droughts will also affect tourism flows, especially in southeast Mediterranean where the maximum demand coincides with the minimum availability of water resources (4).

Deep, temperate lakes

Typical representatives of this class are e.g. Lakes Maggiore, Ohrid, Geneva and Constance with mean depths of 177, 164, 153 and 90 meters, respectively. Due to the great depth and relatively mild winters, there is usually no ice cover. The future climate change in Europe may suppress the turnover in deep lakes. This implies the enhancement of anoxic bottom conditions and an increased risk of eutrophication. The oxygen conditions can also be anticipated to deteriorate due to increased bacterial activity in deep waters and surficial bottom sediment.

Shallow, temperate lakes

Balaton (600 km2, 3 m) in Hungary and Müritz (114 km2, 8 m) in Germany belong to this class. Increasing water temperatures may result in intensified primary production and bacterial composition. The probability of harmful extreme events, e.g. mass production of blue-green algae, will increase. The impacts may extend to fish life; changes in species composition and reduced fish catches will be anticipated. The use of the expression 'thermal pollution' is well justified for these lakes.

Boreal lakes

Ladoga (17 670 km2, 51 m), Onega (9670 km2, 30 m) and Vänern (5670 km2, 27 m) are the largest in this class, being also the three largest lakes in Europe. This group includes about 120 lakes with an area exceeding 100 km2. Most lakes of the boreal zone mix from top to bottom during two mixing periods each year. Shortening of the ice cover period will be the most obvious consequence of climate change in these lakes. This could improve the oxygen conditions in winter and spring.

Arctic lakes

These are mainly small water bodies in northern Scandinavian mountains and in the tundra region. Arctic lakes are generally considered to be particularly sensitive to environmental changes. Melting permafrost may seriously threaten the ecosystems of arctic lakes. In some cases the whole lake may disappear as a consequence of ground thaw and enhanced evaporation.

Mountain lakes

To this class belong all high altitude lakes in central Europe and also those located in southern Scandinavia. Even if mountain lakes were connected by channels, physical and ecological constraints limit species migration between them. In a warming climate, there is no escape route; the only possibility for survival is adaptation.

The Mediterranean sub region

In today's climate the mean temperature varies in January between +10 and -2°C, in July it is generally 20 - 25°C. This sub region covers the narrow coastal area on the Adriatic Sea, most of the Greek territory and the lowlands on the southwest side of the Black Sea.

Only the smallest lakes have short ice cover season every winter in today's climate, in the future climate ice will be almost non-existent. Summertime water temperatures will get very high, leading to algal and water quality problems. Water balance will be negatively affected by climate change; evaporation will increase and inflows tend to decrease. The use of lakes as water sources, e.g. for rising needs of irrigation, will be limited.

In today's climate, the runoff in the Adriatic part of this sub region is generally over 1000 mm, while it ranges between 30 and 200 mm in the vicinity of the Black Sea. The difference of lake precipitation and lake evaporation is 200 - 600 mm in the former area, whereas it is between -200 and -400 mm in the latter. In the climate of 2050, shallow lakes in the latter area will become intermittent and reservoirs will have considerably high water losses.

Northern lowlands

Mean temperature in January is between -5 and -2°C, in July around 20°C. This sub region covers large parts of Hungary, eastern Croatia, central parts of Serbia, southern and eastern Romania, and Moldova. As to the runoff, this is the driest area in south-eastern Europe; in Hungary and on the Black Sea coast annual runoff is locally less than 20 mm. The difference of lake precipitation and lake evaporation is between 0 and -300 mm.

In today's climate most lakes in this sub region mix from top to bottom during two mixing periods each year and have an ice cover for 1-3 months. They may still freeze in 2050, but the possibility of ice-free winters will increase. Adverse water balance changes may affect many lakes; intermittency and increased salinity can be anticipated.

Mountaineous regions

South-eastern Europe is topographically one of the most diverse regions in the world. In addition to two main mountain ranges, Carpathians and Dinaric Alps, there are numerous other ridges and plateaus. At highest elevations, mean temperature in January can be as low as -10°C and extremes below -30°C have been recorded. In July typical mean temperatures are between 10 and 20°C. Precipitation is generally abundant but very variable even at small scale.

Most lakes are located in river valleys, but smaller ones occur also at high plateaus and depressions. Ice cover season may be as long as 5-6 months, snow on lakes further reduces the penetration of radiation into the water mass. Some of the highest lakes mix once a year but mixing twice a yearis much more common.

Climate change may not cause very harmful changes in water balance of these lakes. Increased erosion by intense precipitation may lead to sedimentation and degradation of water quality. At lower elevations, the occurrence of ice cover may become uncertain. For water supply, the mountain lakes and river basins will probably be very important in south-eastern Europe in the future, because run-off may considerably decrease at lower altitudes.

Underground (karstic) lakes

This is a special type of lakes. Due to the karstic geology, there are underground lakes in the Balkan region. They are not immune to the impacts of climate change; in fact their water balance and ecology may be sensitive to changes of the quantity and quality of inflowing waters.

Adaptation measures include (5):

• Modification of existing physical infrastructure, a.o.Modification of existing reservoirs; Removal of sediments from reservoirs for more storage; Modification of existing irrigation systems; Modification of the coastal infrastructure;
• Construction of new infrastructure. In river basins, where full development is not occurring yet, new projects could be developed to adopt the change runoff and water demand conditions like: Construction of new reservoirs; Construction of the new hydro power plants; Construction of new thermo power plants;
• Water pollution control;
• Improvement of the monitoring and forecasting system for flood and drought;
• Drafting and approval of new legislation for water use;
• Setting a real water consumption fee. In Albania, the water supply enterprises charge the consumer with a modest fee, which however do not fully cover the cost. Thus, in the circumstances of reducing drinking water due to climate changes, the real price for water consumption is a measure that should be taken into consideration;
• Implementation of the Integrated Coastal Zone Management Plan: Short-term and long-term measures could help the development of the coastal zone, taking into consideration climate changes.