High seas: “No beaches Arab sinking”

Last century witnessed a rise in sea levels of 17 cm with an average of $ 1,75 mm per year.

The Fourth Assessment published in 2007(of the Intergovernmental Panel on Climate )IPCC ,predicts the rising sea levels up to 59 cm by the year 2100, excluding the effects of dynamic changes in the potential melting of the ice. Taking into account the extent «likely» full projected increases in temperature, the higher sea levels could swell to 1,4 meters by the year 2100. Other researchers predicted rising sea levels between 5 and 6 meters in the case of collapsed ice sheet in West Antarctic (Antarctic).

The Coastal zone in the Arab world is not an exception from the threat of rising sea levels. Like many parts of the world, the capitals and major cities in the Arab countries on the coast or on estuaries. Because the very rapid expansion, this cities are very vulnerable to the threat of rising sea levels.

To look more carefully on the impact of rising sea levels on coastal line, Arab countries are informed that there is a substantial risk that this is already happening, a simulation of rising sea levels was carried out using geographic information system (GIS) and data shuttle radar topography mission (SRTM). These data, which are widely used in many scientific investigations, is the best digital model (DEM), in tuned and accuracy, on a global scale in general under the scenario of rising sea level meters, simulations show that nearly 41,500 square kilometers of Arab countries territory will be directly affected by the high level of the sea. The heights calculated would lead to the displacement the fast growth of the population to areas more crowded. And at least 37 million people (11%) will be directly affected by one meter due the sea-level rise.

In the scenarios of two 3 and 4 meters of sea level rise, about 60,000 and 80.700 square kilometers and 100,800, respectively, in the coastal area will be affected seriously in the Arab region. In the extreme case, where the sea levels rise 5 meters, the impact would be in the highest degree, it is estimated that the flood waters of the sea about 113,000 square kilometers of coastal land.

But the expected impacts of rising sea levels are not evenly distributed across the Arab region. The impact of the rise will be particularly acute in some countries such as Egypt and Saudi Arabia, Algeria and Morocco, while will have less impact on countries such as Sudan, Syria and Jordan.

Egypt would be the country most affected in the Arab world. Not less than 12 million Egyptians will be displaced in one scenario of 5 meters of sea level raised. In fact, Egypt alone has nearly one third of the total Arab population. The UAE, Qatar and Bahrain will have the highest impact of rising sea levels according to the proportion of the population at risk with the total population in the country. Here, we expect to be affected by more than 50 percent of the population of each country at altitudes of sea level of 5 meters. The current analysis indicates that Bahrain and Qatar will be losing about 13,4 percent and 6,9 percent respectively of their territory , according to the scenario of rising sea levels of 5 meters.

Coastal and urban growth
There are natural and human factors may contribute to the impact of rising sea levels and strengthening. For example, for the most parts of the Arab world, civilian growth is rapid and uncontrolled widely along the vulnerable coastal areas. With the persistency to attract larger numbers of people to those areas dangerously low. As a result, it is likely to be higher sea levels a significant impact on people and on the development of infrastructure in coastal areas of the region.

And could be used to monitor historical changes in urban growth to identify future trends in the expansion of civil apart from climate change, and therefore can suggest places that will need to integrate climate risks better in planning processes. Based on studies of satellite imagery classification and the statement of changes analysis is estimated, for example, that statement of changes Dubai's Civil growth (including green areas) will increased the surface area about three times in less than 20 years (between 1984 and 2003). With the addition of the growth area in the draft new civil Islands «Palm» and «world» in Dubai, it gets bigger proportion of the population and infrastructure that are likely to be affected by coastal flooding or dumping.

To estimate the total area at risk from rising sea levels in more detail, was created a digital model of the rise of the coastal zone in Sharjah, Ajman, Umm Al Quwain, from topographic maps. The results show that a rise by one meter will flood approximately 8,1 percent of the Emirate of Ajman and 1,2 percent of the Emirate of Sharjah and 5,9 percent of the Emirate of Umm Al Quwain. With a rise of five meters, the submerged land will increase up to about 24 percent and 3,2 percent and 10 percent in the three emirates, respectively.

The impact of rising seas on the Nile Delta

Nile delta, with sea level rises of 1 meter (dark blue) and 2 meters (light blue), along with population density (lighter to darker browns) and urban areas (hatching). The inset shows the distribution of farmlands.

Low places that are occupied in the Arab region, such as the plains of estuaries (Delta), will face more serious problems due to rising sea levels. And deltas are particularly vulnerable, because the sea-level rise and land subsidence, exacerbated by human intervention, such as sediment retention because of dams. In the Arab world, Delta Co regions are the Nile Delta in Egypt and the Delta of the Tigris and Euphrates in Iraq. These areas are the most densely populated agricultural land in the Territory. As is clear from rising sea levels calculated, these regional districts are most affected. In fact, the effects will be much greater when you take into account an increase in the occurrence of extreme climatic events in the low-lying areas.

From The total area of Egypt, a little more than a million square kilometers, the climate is mostly dry to excessive drought. The desert occupies almost 94 percent of the land mass in Egypt. An approximate 81 million people live on less than 6 percent of total land area in the country.

This area, which is located in the Nile Delta and Nile Valley, contains the most productive agricultural land, and thus constitute a food source for the country as a whole. And the Nile Delta, an area of 24,900 square kilometers, accounting for only about 65 percent of agricultural land in Egypt.

Nile delta river

The Delta, which in the past, used to be the largest site for sediments in the Mediterranean basin, is an extreme example of a low flat area that is very vulnerable to the threat of rising sea levels.

And Delta is currently down by the accelerated deterioration of the coastline. This was generally attributed to human factors and natural. The creation of the Aswan Dam (1962) and the sequestration of a large quantity of sediments in Lake Nasser, are the main actors in the erosion of the Nile Delta. The retention amount of other significant sediment from the Nile because of the irrigation network and drainage channels are dense, and in the wetlands north of Delta, also contributed significantly to the erosion of the delta. At the present time, moving only a small amount of sediments of the River Nile towards the sea to fill the shortage in the Delta on the coast of northern edge. Even a very small portion of the remaining delta sediments, which currently stands to the Mediterranean sea currents remove them eastward.

In addition to this , the sinking of the delta between mm and 5 mm per year, as a result of natural causes and extraction of heavy groundwater, affecting the coastal erosion beyond the border. This effect appears in the satellite images, where coastal erosion can be seen clearly near vertical Rosetta and Damietta. An analysis of satellite images that the head Rashid, in particular, has lost 9,5 square kilometers of coastal area that the plan fell 3 km inland in 30 years (1972, 2003). This means that this part of the Delta decline at an alarming rate of about 100 meters per year.

The Nile Delta will lose more under scenarios of rising sea levels, from forever. Classified analysis of remote sensing and geographic information system some areas in the Nile Delta are at risk of rising sea levels by one meter and the maximum case scenario for sea level rise of 5 meters. Based on this picture, it is estimated that the height of one meter will only inundate much of the Nile Delta, and sprayed about a third (34% ) land, making an important coastal cities such as Alexandria, Edco, Port Said and Damietta in great danger. In this case, it is estimated that about 8,5 percent of the country's population (7 million) will be displaced.

In the extreme case scenario of rising sea levels 5 meters, more than half (58% ) of the Nile Delta will face devastating effects, which would threaten the 10 major cities at least (including Alexandria and Damanhur, Kafr El-Sheikh, Damietta, Mansoura, Port Said), bathing the productive agricultural land , and forcing about 14 percent of the country's population(11.5 million) to move to areas more densely populated south of the Nile Delta region, which contributes to making the standard of living worse than what it is now.

* A research professor at the Center for Space Science at Boston University.