CMI Letter #8, June 2011
Natural hazards and climate change in coastal cities: The World Bank sounds the alarm
According to the Intergovernmental Panel on Climate Change (IPCC), North Africa is the second most vulnerable area to climate risks in the world. The World Bank has just published a study on adaptation to climate change and preparedness for natural disasters in the coastal cities of North Africa which was recently presented within the framework of the programmes of the Centre for Mediterranean Integration (CMI).
The report was written under the direction of senior urban specialist Anthony Bigio, lead author and member of the Intergovernmental Panel on Climate Change (IPCC), and with the help of a team of climatologists, experts in hazard and disaster management and a group of companies led by Egis International. The World Bank study on adaptation to climate change and preparedness for natural disasters in the coastal cities of North Africa was presented to the CMI at a regional seminar on May 30-31. Faced with the threat climate change poses to Mediterranean countries, in particular countries along the southern rim, the World Bank has for a number of years been concerned with the potential effects of natural disasters on large coastal towns and cities.
During the seminar, Franck Bousquet, sector manager, urban and social development at the World Bank, stressed “the importance of the voice and accountability agenda, especially following the recent Arab spring, which could translate in many cases, into stronger local-level institutions as citizen participation typically needs local intermediaries”. He also emphasized “the impetus given to urban development in the region, where the urban share of total population will grow from 56% in 2005 to 65% by 2030. Urbanization needs to be well managed to avoid informality and poverty”.
These rapidly-growing cities face specific threats that will become more acute in the coming decades as the impacts of climate change become stronger. The MENA region (Middle East and North Africa) has already seen an increase in the occurrence of natural disasters: the average number of natural disasters per year in the region rose from 3 in the 1980s to 15 in 2006. Of the 276 natural disasters recorded in the region during the period 1980-2006, 120 took place in the last five years*.
The study analyses three cities (Alexandria, Casablanca and Tunis) and the Bouregreg valley in Morocco, just outside Rabat. The inhabited wadi in the Bouregreg valley is the focus of a vast urban development project. The study includes a table describing these four sites in their present condition and their expected state in 2030, and analyses the extent of their exposure to natural disasters, extreme weather events and the influence of climate change on these phenomena. The results from the two year study mean that it is now possible to evaluate the risks and costs of potential losses, as well as plan for adaptation and investment that will allow cities to protect their populations.
Apply the rules
The study shows the importance of developing new urban development regulations that reflect risks by assessing urban growth projects. States must direct urbanisation towards safe areas, in particular in expansive cities such as Tunis, Casablanca and Alexandria. The role of government is to assess current risks and reflect the advice of local urban planners by reviewing plans for highly vulnerable zones, such as the areas north of Tunis and near its southern lake.
The situation faced by Tunis is replicated across the southern rim of the Mediterranean, due to intense pressure from growth in urban areas. In 2010, coastal cities in the region had a combined population of around 60 million. By 2030, this number is projected to exceed 100 million, exposing an increasing number of people and economic activities to risk. Alexandria, Casablanca and Tunis, which had populations of around 10 million in 2010, will have around 15 million residents in 2030**.
+ 20 cm in 2030
The authors of the study are working with a basis of 20 cm sea level rise due to climate change between now and 2030, as well as more violent storm activity***. Tunis, the most vulnerable city studied, will see the risk of soil instability and marine flooding increase from average to high, and the risk of coastal erosion and flooding will increase from high to very high. The main threat to Casablanca is coastal erosion and flooding, while Alexandria is most threatened by marine flooding, water shortages and coastal erosion. The warning indicators for marine flooding and flooding in the Bouregreg valley will increase on the colour index from orange or red. In total, between 2010 and 2030 each of these three cities will be exposed to potential economic losses well in excess of one billion dollars, while the housing project in Morocco’s Bouregreg valley will put the lives of its inhabitants at risk if action is not taken to mitigate the identified risks. The scenario is of even greater concern as all of the scientific data projects a significant increase in the consequences of climate change for 2050 and beyond. The situation will only get worse.
For decision-makers in government, the challenge is to analyse the cost/benefit ratio when making difficult financial choices between investment in projects and financing necessary levels of protection against natural hazards
Reducing risk exposure requires that three types of action be taken. First of all, climate change must be taken into account in urban planning decisions. Secondly, improvements must be made in public information, rapid warning and communications systems, as well as the operations of institutions responsible for these systems. Finally, urban protection and drainage infrastructure must be put in place. The first two measures will be the most effective and require the least investment; the third requires significant levels of investment. The costs associated with these undertakings can be greater than the damage they are intended to prevent. “However, these measures can be justified, for example, in terms of the value of the heritage found in the areas in question”, according to the study.
The study was conducted in collaboration with national authorities in the countries studied. The results and priority recommendations for action resulting from these studies and the two day workshop will be shared with other countries and cities in the Mediterranean as part of the programme of activities of the CMI.
Alexandria under threat from floods and drought
Tsunamis, coastal erosion and water shortages could be the three plagues of Alexandria for the next 20 years.
Alexandria was devastated by two tsunamis in the past, one in 365 A.D. and another in 1303 A.D., with waves measuring one to three meters in height. Statistically, this type of disaster happens every hundred years. Therefore, sooner or later the inhabitants of this city of 4.1 million people, with an expectation of 6.8 million inhabitants by the year 2030, should expect to feel the effects of seismic activity in Greece.
The cumulative potential damage from natural disasters and climate change impacts is estimated to be $1.72 billion in Net Present Value for the period 2010-2030****.
The city is growing extremely rapidly, leading to the urbanization of new land, with the poorest populations settling on land in coastal areas that is often below sea level. Sea level rise- a critical climate change risk for coastal cities- is an important unknown but is assumed in the study to be 20 cm by the year 2030. The higher seas would compound storm surges, increasing the risks for marine inundation and coastal erosion*****.
Coastal areas close to Abu Qir are directly threatened by flooding from the sea. The Mohammed Ali Dam could give way during a major earthquake or tsunami, and the areas below sea level would be at risk of flooding.
The recent rebuilding of the Corniche road magnifies exposure to natural hazards. It has heightened the existing phenomena of coastal erosion and storm surges by accentuating the slope of the seabed.
With greater urbanization, the overall ground area will become increasingly impermeable, adding to runoff and drainage problems.
While the city will see the risk of flooding increase over the next few years, it will also suffer from water shortages at the same time. The sharp rise in population growth in Egypt and an ever-increasing industrial demand will probably result in water shortages”. Demand for water has increased 50% over the past decade.
The study also examines the people who will be impacted by natural disasters. In Alexandria, the study notes that the current system coordinate relief efforts after disasters, but does not have any early warning capacity. The study encourages Egyptian decision-makers to focus on preventive actions. Improving early warning systems is seen as a particularly wise investment. A system of “smart buoys” along the coast could provide real-time information.
Prevention also means urban planning to redirect the expansion of the city areas away from areas identified as most at risk, and to establish a land-use program with rules for densities, building heights and open space ratios taking into account future climate scenarios.
These control and prevention measures are relatively modest investments as compared to the cost of building coastal defense infrastructure.
The full contents of the study can be found in “North African Coastal Cities: Address Natural Disasters and Climate Change”. Summary of the regional study, June 2011, World Bank/CMI.
*“North African Coastal Cities Address Natural Disasters and Climate Change”. Summary of the Regional Study, June 2011, World Bank/CMI, p.1.
**“North African Coastal Cities Address Natural Disasters and Climate Change”. Summary of the Regional Study, June 2011, World Bank/CMI, p.2.
***“North African Coastal Cities Address Natural Disasters and Climate Change”. Summary of the Regional Study, June 2011, World Bank/CMI, p.17-18.
**** “North African Coastal Cities: Address Natural Disasters and Climate Change”. Summary of the regional study, June 2011, World Bank/CMI, p.9.
***** “North African Coastal Cities: Address Natural Disasters and Climate Change”. Summary of the regional study, June 2011, World Bank/CMI, p.3.