Climate change and impacts in the eastern Mediterranean and the Middle East
The Eastern Mediterranean and the Middle East is made up of 24 countries. After a lot of years of intense industrialization, rapid population growth and extensive land conversion the EMME is now a global climate change "hot spot ".
PRESENT CLIMATE CONDITIONS
The crossroad that EMME finds of global climate patterns gives a convergence over the region, extensive adjacent land masses transporting continental air and extreme differences in topographical features.
One of the most prominent is the north Atlantic Oscillation (a large-scale of atmospheric air masses). The El Nino/Southern Oscillation also influence the EMME'S climate, as El Ninion brings dry conditions.
Apart from the remote and indirect climate effects NAO and ENSO bring, the EMME'S weather is directly by the Red Sea through, tropical intrusions and dust storms from the Sahara desert. Is also impacted by the massive South Asian monsoon that is creates large-scale subsidence over the central and eastern Mediterranean reducing converting and producing clear skies.
The current climate is already fairly extreme with temperature and precipitation changing rapidly across the region. The northern EMME had a climate with warm and hot dry summers, occasional droughts and mild, relatively wet winters. The southern EMME there is a little rainfall (encounter an arid and hot desert-like climate). There is much concern in the EMME region (will have disproportional effects compared to other areas)
Climate of the past half millennium: A history of change
The seasonality of rainfall is major importance to the pre-1960.There is an obvious northwest-southeast gradient in the amount of winter precipitation. In the pre-20 century period can also be identified wetter and dry period.
The early 20 Century is characterized by a strong increase in summer mean temperature until around the 1950s when a cooler period began.
The annual mean temperature in the EMME region since 1960 ranges from about 0C in mountainous areas to about 15-17 C in northern coastal parts except the southern part of the region that has a notably different regime with a mean temperature range of 18 to 28 C. Exceptionally strong warming period started at the mid-1970s (hottest summer 2003)
The large north-south contrast is evident in both annual and seasonal rainfall pattern. In the northern EMME the average total annual precipitation between 1961 and 1990 ranges from approximately 500mm in the east to more than 1000 mm in the west.
Rainfall deficits and summer dryness are commonplace in the southern part of EMME. The dominance of differences in topography is evident from the localized high winter precipitation levels(drying trend starting 1960s , lowest precipitation 1990s).
Future projections of climate change: A hot dry
Research predicts that the temperature is likely to increase between 2-4 C in winter and 2-6 in summer over the coming century. The warming will be gradual. Ranging next three decades :1-3C, in the mid21 century:3-5 C, end of the century : 3.5-7 C
Overall rainfall is predicted to increase by 20-30% throughout the EMME over the course of the 21 Century and more severe droughts are expected in the Mediterranean. Precipitation may significantly decrease in winter along the eastern Mediterranean coast by between 30-50 %, although elsewhere in the south-eastern Middle East there may be increases though modest in absolute terms considering the small annual rainfall. In summer, the EMME drying is also significant.
Reds and oranges highlight lands around the Mediterranean that experienced significantly drier winters during 1971-2010 than the comparison period of 1902-2010.
In the future we can wait a remarkably large increase in the number of hot days per year with the biggest increase appears over the Levant and along the North African coast. Hot nights will gradually increase with hot nights warmer than 25C by more than two months per year.
The heat waves has major implications for human health, energy use and economic activity. The Middle East has been identified as the first region worldwide to effectively run out of fresh water and access to drinking water will become a critical issue as parts of the EMME essentially dry out.
Air pollution and desert dust: Changes to air quality
High levels of air pollution in the EMME region (natural, anthropogenic origin). The fine aerosol particles are mostly composed of sulphates and particulate organic matter, whereas the coarser particles are dominated by desert dust. The levels of fine aerosol particles in the EMME region are expected to rise substantially during the mid-21 Century due to increasing emissions of sulphur dioxide and nitrogen oxides.
The relatively intense solar radiation promotes the formation of ozone, as in the summer the EMME is largely cloud-free. The Mediterranean ozone levels are the highest in the world. It is likely that ozone levels will continue to increase with especially high levels around the Persian Gulf.
Since population growth and urbanization in the southern and eastern parts of the EMME will likely continue, the situation of poor air quality is expected to aggravate until appropriate measures are implemented.
Overall emission controls are considered to have a stronger influence on air quality than climate and land-use changes. In future the expected increases in warming and drying will be conducive for ozone formation especially during heat spells.
Human health concerns
Children and elderly suffer disproportional from extreme temperatures and the heat waves can also increase air pollution concentrations. It's probably tha its become more common in the EMME. The increase of hot nights in the southern EMME will exacerbated the heat stress and the associated health issues.
After several decades of steady decline in vector-borne parasitic and viral diseases throughout the EMME region, a recent upsurge of these diseases has occurred. Vector-borne diseases are now spreading northward from Africa and have become an emerging threat in the EMME.
Malaria: This is considered to be a highly climate-sensitive tropical disease. West Nile Fever: The occurrence of this virus is connected to climatic factors particularly where heat stress is enhanced by high humidity. Leishmaniasis: This is the only tropical disease that has been endemic to southern Europe for decades, and studies indicate that the disease is emerging.
Crimean-Congo Hemorrhagic Fever: The optimum conditions are increasingly fulfilled in the EMME region.
Land ecosystems and agriculture
Overall the future effects of climate change on crop production are expected to be negative, at least for the major crops grown in the EMME.
Climate change can affect agriculture directly though the meteorological conditions that influence crop growth and yield. By the mid-21 Century the length of the EMME growing season may increase by about one month per year in the northern EMME. As an example we can see in the below graph the areas which are switable for grapes now and the areas which will be suitable on 2050.
Most importantly for crop cultivation, the occurrence of very hot days will increase by two to four weeks per year by mid-century.
In the northern part of EMME heavy precipitation will increase by several days per year and decrease in southern parts. Also we have the increase of evapotranspiration and the decrease of soil moisture in dry areas.
The Mediterranean region of the EMME is among the world's highest plant biodiversity areas and is expected to suffer the greatest decrease as a result of climate change. In the EMME the vegetation at the rim of its natural distribution is expected to be most sensitive. The increased, intensity and duration may critically disrupt the balance between pathogens and vegetation.
The Mediterranean Sea: Changes to marine ecosystems
Marine biodiversity in the Eastern Mediterranean Sea is thought to be particularly susceptible to this, with impacts predicted to become exacerbated even within the next 10 years.
An observed abrupt change in the eastern Mediterranean Sea circulation during the 1990s is attributed to increased salt content from less rain, reduced outflow, less river runoff, cooling from severe winters and changes in wind stress.
Oxygen utilization rates in the bottom and intermediate waters of the Eastern Mediterranean basin increased twofold following the change to circulation patterns, probably due to greater availability of dissolved organic carbon at these depths. Mesozooplankton biomass nearly doubled and species previously found only in the northern most margins of the Mediterranean Sea suddenly became abundant.
By the end of this century the warming will continue to dominate throughout the 21s Century with a sea surface temperature increase of 2.5-3 C. Mediterranean sea surface and deep waters they have increases in salt content about 1.3-2.5 cm per decade.
Circulation patterns and sea level are anticipated to significantly affect ecosystem function in the Mediterranean Sea. Higher water temperatures, reduction in nutrient delivery to the surface waters and overall warming of the Mediterranean Sea ecosystems.
There will also be movement of alien species from outside the Mediterranean Sea ecosystems as circulation changes and temperatures rise.
Predicted biodiversity changes in the Mediterranean Sea
The Mediterranean ecosystem
The Mediterranean Sea has a relatively high species diversity, largely due to its long evolutionary history and the prehistoric introduction of many Atlantic species into the Mediterranean. The present-day high species richness is due to spatial coexistence of warm water species (thriving in the summer) and cold-water species (thriving in the winter). This seasonal change in species activity is a buffer against the effects of environmental variation, because a varied set of species is more likely to adjust to environmental change.
Since the 1980s, the Mediterranean marine biota have experienced rapid, dramatic changes, illustrated by alteration of food webs, mass mortalities, and population explosions such as jellyfish outbreaks. These changes are caused by intense anthropogenic activities, but also by climate change.
The advance of warm-water species represented the first evidence of a linkage between climate change and distribution patterns in the Mediterranean Sea. This phenomenon is particularly evident in fish, where over 30 native (warm-water) species have already spread into northern areas. Almost all of the 100 fish species newly recorded in the Mediterranean are of warm-water affinity. At the same time, the physical properties of the basin have changed and temperatures have increased.
Endemic native species with cold-water affinity, common in the northern part of the Mediterranean, will probably decline and eventually be lost. A decline in their occurrence has been reported already. It is also possible that some of these species might become adapted to the new conditions, after periods of stress.
The seaweed Fucus virsoides, an endemic flagship species of the Northern Adriatic (the coldest portion of the Mediterranean Sea), appeared to suffer severe stress in former years, whereas it is now particularly abundant, for example in Venice. In general, the recent warming has facilitated the establishment and distribution of tropical, exotic species that have been introduced either via the Suez Canal or by maritime transport. This process is fast advancing, and more than 500 non-indigenous species have already been recorded in the Mediterranean. Some undoubtedly raise some concern, such as the jellyfish Rhopilema nomadica – which even shut down a nuclear power plant by clogging its cooling system – whereas others are becoming a resource for fisheries. Entire replicas of tropical communities from the Red Sea have already been recorded from a few Mediterranean locations.
From this it can be concluded that if the Mediterranean continues to warm at the same rate, all its sub-regional, biological peculiarities may rapidly disappear, to be replaced by a more homogeneous, tropical-like ecosystem.
Changes to freshwater resources
Countries in the EMME region are already notorious for water scarcity,and the demands from population growth and economic development are increasing.
This figure shows the rate of change of the ‘water balance’. The map provides an estimate increase (red in map) or decrease (blue in map) of the volume of water required from irrigation assuming that all other factors are unchanged and given that there is an irrigation demand.
This figure shows the relative change in water availability for irrigation as projected under the A1B emission scenario by the HIRHAM (DMI) regional climate model for 2071-2100 relative to 1961-1990. Light yellow areas indicate no change in water availability.
The mean annual precipitation in the EMME will probably decline between 10-50% during the 21s Century. As a result the average annual river discharge of the Euphrates, Tigris and Jordan rivers could decline by between 10-22% by the mid-21 Century.
Population projections combined with the predicted internal water resource availability suggest that by the mid-21 Century, water shortages will worsen in all countries which are currently water scarce; the changes will necessity major adaptation in the agricultural sectors of countries.
Despite the potentially costly nature of this solution extensive desalination is considered to be required even the most basic water needs. The climate change effects on water resources will be significant and some countries may struggle with the costs of providing fresh water through desalination
By the end of the 21s Century most of the northern Mediterranean coast an additional 2-3 weeks per year and in North Africa it is expected that more than one additional month per year of heavy air cooling will be required. These major impact climate change will have on energy demand.
The decrease is most evident in the northern continental parts, given the high temperature condition in the southern EMME the heating requirements are minor. Also small decreases in the winter temperature are projected in North Africa and the Middle East.
The additional energy happens to coincide with a deficit in water supply which also reduces energy production by hydroelectric plants in the northern EMME, at the same time will occur as a growing demand for desalinated water. In EMME countries with limited resources, there is expected to be an increasing disparity in power supply and a growing need for innovative solutions. Changes in demand for heating they are unlikely to help over the growing problems with energy supply.