About Mediterranean Region
Where is it?
The Mediterranean region is defined as countries bordering the Mediterranean Sea (plus Portugal) between about 27° to 47°N and 10°W to 37°E. The Mediterranean, which literally means the “sea between lands”, offers favourable environmental conditions, such as climate, biological diversity and natural resources. Since earliest times, different people from faraway lands have chosen its shores to settle and it is the birthplace of some of the oldest, most deeply rooted cultures and civilisations of our planet (Egyptian, Greek, Roman and Arab), and of three of the most influential global religions: Christianity, Islam and Judaism.
The Mediterranean Sea is the largest of the semi-enclosed European seas. It is surrounded by 18 countries and has shores on three continents (Europe, Africa and Asia) with a combined population of 129 million people in the catchment draining into sea, and sharing a coastline of 46 000 km. It is one of the leading tourist areas in the world, hosting 100 million visitors every year. This influx of people increases the waste discharges from domestic and industrial sources.
The Mediterranean Sea has an average depth of 1.5 km, though more than 20 per cent of the total area is covered by water less than 200 m deep. The sea consists of two major basins, the eastern and the western. There are also smaller regional seas within the Mediterranean: the Ligurian, Tyrrhenian, Adriatic and Aegean seas. It is linked to the Atlantic by the Strait of Gibraltar, with the Black Sea and Sea of Azov by the Dardanelles, the Sea of Marmara and the Bosporus, and with the Red Sea by the Suez Canal. The Mediterranean Sea is characterised by low precipitation, high evaporation, high salinity, low tidal action and relatively low nutrient concentrations outside the inner coastal zone and parts of some regional seas.
The coasts of the northwestern Mediterranean are the most affected by pollution because of the concentration of urban populations, industrial activities and discharges of major rivers including the Ebro and the Rhone. The Adriatic receives the discharge of the River Po. The North African coast, in contrast, is for most part arid with little urbanisation or industrialisation. Pressures on the marine environment therefore vary widely depending on the local or regional situation.
The Mediterranean is also a sea of communication and trade, as well as cradle of democracy, the welfare state and the most important periods of freedom that humanity has ever enjoyed. Its climate is characterised by mild, wet winters and hot, dry summers. Speciality crops of the region include olives, citrus fruits, grapes, and cork. However, tourism is a major source of income for many of the countries bordering the Mediterranean.
The region includes the Northern countries such as: Albania, Bosnia-Hergovina, Croatia, France, Greece, Italy, Malta, Monaco, Serbia-Montenegro, Slovenia, Spain; and the South-Eastern Countries such as: Algeria, Cyprus, Egypt, Israel, Lebanon, Morocco, Libya, Palestinian Authority, Syria, Tunisia, and Turkey.
The countries of the Mediterranean region cover 8,759 million km2 and presently hold 427 million people. The population of the northern-rim nations will grow from 192 million in 2000 to 196 million in 2025; the population of the southern- and eastern-rim nations will grow from 235 million to 327 million.
The Mediterranean component of the CLIMAGRI project (CLIMAGRIMED) refers to partnership among Italy and some developing countries in the Mediterranean region such as: Algeria, Cyprus, Egypt, Lebanon, Morocco, Libya, Syria, and Turkey.
The climate change issue has emerged as the major environmental. The current and future levels of energy use from burning of fossil fuels and clearing of forests for cultivation can have profound effects on the global environment, and on key economic sectors in the present century. Global warming presents a challenge to understand what is at stake and to manage future development in a sustainable way.
Several Global Circulation Models (GCMs) have been developed by atmospheric scientists in various research groups and have been used to project the effects of greenhouse gas increases.
The main problem faced when using GCMs is the spatial resolution, which is too coarse (about 5°x5°) to work out impacts analysis at a regional scale, especially over such complex areas as the Mediterranean region. As a consequence, downscaling techniques have to be applied to GCM results in order to get higher resolution results. This can be achieved using a statistical model based upon regression techniques.
Results from these simulations show a mean global warming in the range of 1.5 to 4.5°C by the end of the next century. When the effects of sulfate aerosols are included in the projections, the best estimate for 2100 is a temperature increase in the range of 1.0 to 3.5°C. These projections are somewhat cooler since sulfate aerosols from industrial pollution tend to cool the earth.s atmosphere. GCMs also predict that an increase in mean global precipitation ranging from about 5 to 15%. GCMs further predict that:
Sea-level rise is one of the major impacts projected under global warming. Other factors that are directly affected by climate include river flow, runoff, soil characteristics (including salinization), erosion and water quality.
- The high latitudes are likely to experience greater warming than the global mean and warming, especially in winter.
- The hydrological cycle is likely to intensify, bringing more floods and more droughts.
Observed climatic changes in Mediterranean
The analysis of the studies, which have dealt with the climatic changes in Mediterranean and especially in Greece, shows poor agreement even conflicts among the results. Even thought the observed trend of climatic elements could be attributed to human activities, the extent of the variations is such that probably falls in the range of the natural climatic variability. However, specific findings are summarised below:
Detection of climate change on this scale is extremely difficult as the high variability in local climates masks trends in the 'noise' of natural fluctuations. Moreover, the short period of observations makes the identification of clear trendsdifficult and creates uncertainty over the scale of natural variability.
The analysis of the surface air temperature averaged all over the basin, indicates an evolution similar to that one recorded either on the global or the hemispheric scale; namely a cooling during the period 1955-1975 and a strong warming during the 1980s and the first half of the 1990s. However, the east-west Mediterranean difference in air and sea surface temperature trends is distinctive.
Sea surface temperature records for the Mediterranean region, especially the eastern Mediterranean, show a rapid cooling in 1970s while warming was resumed in the late 1970s. The cooling in the east of the region during the 1970s was much more marked than in the west.
Most of the results of the studies concerning air temperature in Mediterranean agree that there has been a positive trend in west Mediterranean and a negative trend in east Mediterranean for the periods 1950-1990 and 1975-1990. Cold period of the year appears to contribute mostly in this observed cooling of the east Mediterranean.
Air temperature in east Mediterranean presents a negative trend from the 1960s to the minimum of the 1970s; ever since the temperature is rising. The year 1999 was considerably warm for east Mediterranean with regard to the 1961-90 average, similarly to the global scale. This is due to the high summer and autumn temperatures.
The mean temperature in the central-west Mediterranean for the 20th century shows an increase of about 0.8°C/100 year.
Since 1900, precipitation decreased by over 5% over much of the land bordering the Mediterranean Sea, with the exception of the stretch from Tunisia through to Libya where it increased slightly.
In particular, a negative trend is likely to be present from early 1960s to 1990; ever since this trend is turning over.
A general drying is evident over most of southeastern Mediterranean and Greece up to the early 1990s. However, it should be noticed the increased precipitation during the recent years. A precipitation decrease has been observed as well during the last 50 years in the central-west Mediterranean.
Future changes of climatic parameters in Mediterranean
Confidence in local and regional climate predictions, as in the case of Mediterranean and Greece, is lower due to the weakness of models in predicting the regional and local effects of climate change. Projections vary widely depending on the model and the test area. In order to estimate climatic changes on this scale, a better knowledge of many complex processes is required.
Global temperatures are expected to increase about 0.2°C/decade and climb by between 1.7 and 4°C by the year 2100. A number of models indicate that precipitation will increase in mid and high latitudes, especially in winter, and decrease in subtropical zone.
All model simulations for Europe aggree that on the average the range of temperature rise is expected to be higher in North Europe in comparison to the Mediterranean areas. Despite that the prediction of the temperature change varies widely, most of the models suggest that the winter temperature will increase more over North Europe while in summer the increase will be higher over South Europe. Moreover, the winter temperature increase over North Europe will be higher than the increase in summer whereas the summer temperature increase over South Europe will be slightly higher than the increase in winter.
Concerning precipitation, most of the models aggree in winter increase over North Europe and give some indications for increase in summer precipitation. These results could be positevely correlated with the obseved general increase over North Europe in 20th century. On the contrary, all models suggest that the summer temperature over South Europe will be declined whereas there are only some indications for an increase in the summer precipitation.
Models offer conflicting evidence over how climate may change on average over the Mediterranean region and particularly over Greece; thus it is very difficult to distinguish possible future climatic changes on this scale. All model simulations, however, have one common feature: temperature will increase considerably during the next decades.
However, specific findings are summarised below:
Temperatures over Mediterranean may increase to as high as 3.5°C by the year 2050 assuming a doubling of the CO2 concentration. The estimation of warming range over Mediterranean presents a considerably high variation (2.0 to 6.0°C by the year 2100). A lower temperature increase is expected over the sea and the coastal regions compared to the inland Mediterranean areas. The regions presenting the maximum temperature increase and sensibility are over the southern part of the Mediterranean.
Summer temperature increase over Mediterranean is substantially higher than the one over North Europe. Concerning the seasonal differences, warming over Mediterranean in winter is of the same order (or it is slightly lower) with the corresponding warming in summer.
Most projections point to significantly less precipitation in summer over the region as a whole. On the contrary, several models suggest an overall increase in winter precipitation mainly over the north part of the Mediterranean region; this increase however is quite less than the one in North Europe.
In general, the prospects for precipitation over the Mediterranean region in a warmer world are still highly uncertain due to the general weakness of general circulation models (GCMs) in predicting regional precipitation. Most models offer conflicting evidence over how precipitation may change on average over the Mediterranean region. A common feature, however, of many projections is that the increase of annual precipitation over much of the Mediterranean region north of 40 or 45° N is more likely, whereas to the south of this projections point to less precipitation.
Extreme weather events
Despite the uncertainties over exactly how climate variability and extremes will change in the Mediterranean region, the overall picture does suggest an increase in the frequency of extreme events and, in particular, of droughts in the western Mediterranean.In general, warmer conditions over the Mediterranean region should lead to an increase in the occurrence of extremely high temperatures and a decrease in extremely low temperature events.In areas experiencing a general decrease in precipitation, droughts are likely to become more frequent as the probability of dry days and the length of dry spells increases.
The climate system consists of a series of fluxes and transformations of energy (radiation, heat, and momentum), as well as transports and changes in the state of matter (e.g., air, water, and aerosols). Received solar radiation is the major energy source that powers the entire system. The flows and transports occur between and within the main components of the system: the atmosphere, oceans, land, biota, and cryosphere (the domain of ice and snow). The system varies regularly due to the shape of the earth’s orbit, its angle, and daily rotation, but also irregularly because the atmosphere and the oceans are both fluids subject to internal movements associated with random turbulence, as energy is transported and transformed through the climate system. These latter variations result in climate extremes.
Climate is defined as the prevalent pattern of the weather observed over a prolonged period of time. Climate variables (e.g., temperature, precipitation, wind speed) can be time-average on a daily, monthly, yearly, or longer basis. Associated with the average states of climate variables are indications of their oscillations or variations about their mean values. The term climate change refers to an overall alteration of mean climate conditions, whereas climate variability refers to fluctuations about the mean. The changing climate will bring changes in climate variability, and may already be doing so.
Through burning fossil fuels and eradication of forests, human activity has caused the carbon dioxide (CO2) concentration of the atmosphere to increase by some 25% since the industrial revolution, and that increase continues. Measurements made on Mauna Loa in Hawaii since 1956 reveal the recent CO2 trend.
CO2 plays an important role in inhibiting the escape of the heat radiated by the earth. The sun beams short-wave radiation to the earth, which sends long-wave radiation back to space. Greenhouse gases in the earth.s atmosphere (carbon dioxide, water vapor, methane, nitrous oxide, and the chlorofluorocarbons) absorb the outgoing radiation, thereby holding heat near our planet. This process occurs naturally: without the natural greenhouse effect, our planet would be near freezing. Instead, this process warms the earth to its current mean temperature of about 15°C.
Climate Change and Agriculture
While agriculture is a complex sector, the system is still dependent on climate, because heat, light, and water are the main drivers of crop growth. Plant diseases and pest infestations, as well as the supply of and demand for irrigation water are also dependent on climate. There is now concern that the effects of climate variability on food production and costs will be exacerbated due to global warming with its potential for affecting the climatic regimes of entire regions. Furthermore, such shifts in climate in different nations may have different effects on agricultural productivity and costs.
World food production varies by several per cent from year to year, largely as a result of weather conditions such as the inter-annual climatic variability in the Mediterranean and Sahel regions. But agriculture in some regions is more sensitive than in others. Typically, sensitivity to weather is greatest firstly in developing countries, where technological buffering to droughts and floods is less advanced, and secondly in those regions where the main physical factors affecting production (soils, terrain and climate) are less suited to farming. A key task facing those concerned with conducting climate impact assessments is to identify those regions likely to be most vulnerable to climate change, so that impacts can be avoided (or at least reduced) through implementation of appropriate measures of adaptation. The key questions for vulnerability/adaptation assessment are likely to be:
- Will climate change significantly affect domestic agricultural production?
- Will climate change cause food shortages and lead to an increase in hunger?
- Will climate change threaten exports?
- Will climate change affect key government policies such as agricultural pricing,
- support, research and development?
- Will climate change increase food prices to consumers?
- Will climate change, acting through agriculture, place greater stress on natural resources or contribute to environmental degradation (e.g., through land-use change, soil degradation, changes in water supply and water quality, pesticide use, etc.)?
While for the national policy maker the primary questions are likely to include:
- What components of the farming system are particularly vulnerable, and may thus require special attention?
- Can the water/irrigation systems meet the stress of changes in water supply/demand?
- What policies and programmes exist to protect populations from hunger/financial
- distress and how will they operate under climate change?
- Is the agricultural research/extension system capable of providing adaptation advice to farmers? What technological options should be investigated? Does the country have access to potentially useful options developed in other countries?
- Should domestic agricultural policies be reformed?
- Are the natural resource management programmes adequate?
- If domestic production is threatened, will the country be able to import food, and (if so) at what cost?
A well structured framework to analyse the impact of climate change to Italian agricultural sector and water resources is reflected in the various research themes of the CLIMAGRI project.
CLIMATIC CHANGE: EFFECTS IN THE AGRICULTURE OF THE MEDITERRANEAN REGION
Summary Points from Presentations by Ana Iglesias, Mediterranean Agronomic Institute of Zaragoza- IAMZ-CIHEAM (Mediterranean Agronomic Institute of Zaragoza of the International Centre for Advanced Mediterranean Agronomic Studies)., Zaragoza, Seminar on Climatic Change: Effects on Agriculture in the Mediterranean Region. Zaragoza, 25-29 September 2000.
CLIMATIC CHANGES IN MEDITERRANEAN
National Observatory of Athens, Lofos Nimfon, 11810 Thession, Athens, Greece
STATUS OF KNOWLEDGE ON GLOBAL CLIMATE CHANGE: REGIONAL ASPECTS AND IMPACTS IN THE MEDITERRANEAN BASIN, A scientific and strategic report to Blue Plan
Blue Plan Regional Activity Center, Sophia Antipolis, December 2001
MEDIAS/GB/db/2001-200 Toulouse, December 7th, 2001