Irin, Saturday Nation 22 May 09;
NAIROBI: Several large African cities are at risk from rising sea levels and intense storms, experts warn.
Poor neighbourhoods and slums in Bugama and Okrika in Nigeria, Freetown in Sierra Leone, Bathurst in the Gambia and Tanga in Tanzania, are especially vulnerable.
In such low-income urban centres, infrastructure is often non-existent or ill-maintained while storm-water drainage infrastructure is often outdated and inadequate, according to a World Bank report titled Sea level Rise and Storm Surges.
According to the Intergovernmental Panel on Climate Change (IPCC), a trend has emerged since the mid-1970s where storms tend to last longer and become more intense, with a strong correlation to the rise in tropical sea surface temperature.
In sub-Saharan Africa, storm surge zones are concentrated in Madagascar, Mauritania, Mozambique and Nigeria. These countries alone account for about half (53 per cent) of the total increase in the region’s surge zones resulting from sea level rise and intensified storms.
At least three cyclones struck Madagascar between January and April 2009, affecting thousands.
In Mozambique, one of the most vulnerable coastlines in Africa, 15 of the 56 tropical cyclones and tropical storms that entered the Mozambique Channel from 1980 to 2007 made landfall.
Tropical cyclones, also called typhoons and hurricanes, are powerful storms generated over tropical or sub-tropical waters whose impact includes extremely strong winds, torrential rains, high waves and damaging storm surges, leading to extensive flooding.
“Coastal flooding has started to be of concern in the last 10 to 15 years,” Pedro Tomo, director of the Mozambique National Institute for Disaster Management, told IRIN. “Now, a few times each year, there are people who wake up in water.”
In 50 years, Tomo said, some coastal towns will disappear if nothing is done.
Such a scenario would not just displace the population, but also damage economic infrastructure, said Michel Matera, an official of the UN Development Programme in Mozambique.
At least 2.5 million people live in Mozambique’s coastal areas, surviving on rain-fed farming and fishing. But migration to coastal towns is placing more people, infrastructure and services at risk, according to a study by the Mozambique institute.
Researchers project a 3-5 per cent increase in wind speed per degree Celsius increase of tropical sea surface temperatures. “The current understanding is that ocean warming plays a major role in intensified cyclone activity and heightened storm surges,” the study stated.
In a scenario of a high, non-linear sea-level rise due to polar ice melting, Beira (a coastal town) “will be cut off from the interior and will likely become an island...” Maputo’s port, its rail links and oil facilities, which are on an estuary, are also subject to flooding.
Studies show that Mozambique, Ghana and Togo may lose more than 50 per cent of their coastal gross domestic product (GDP), but losses would be highest in Nigeria (US$407.61 million).
Coastal agriculture, in terms of extent of croplands, will be affected 100 per cent in Nigeria, 66.67 per cent in Ghana, and 50 per cent in Togo and Equatorial Guinea.
Mauritania is experiencing the impact of a changing climate exemplified by a steadily creeping desert and other extreme weather events. It is one of the countries likely to be worst affected by intensified storm surges.
Mauritania relies mainly on sand dunes as a natural barrier to control coastal flooding. The dunes cover a 5km stretch into the capital, Nouakchott.
Much of the land in and around Nigeria’s commercial capital Lagos, is less than 2m above sea level so it, too, is expected to be affected by rising sea levels.
In Cotonou, Benin, the continued advance of the sea, coastal erosion and the rise in sea levels are already threatening vulnerable communities and disrupting the least-protected sensitive ecosystems.
Zanzibar is experiencing marine flooding, partly due to mangrove and coconut plantation felling, said Waride Jabu, director of the disaster management department.
Jabu said high tidal waves were increasing. “So far, no damage to infrastructure has been noted, but the sea seems to be slowly eating the shore.” The Zanzibari disaster department was encouraging reforestation along the coastline.
In Eritrea, trees are being planted on the 1,100km coastline, said Solomon Haile, the director of the planning and statistics division in the Ministry of Agriculture.
More than half the coastal population of Djibouti, Togo, Mozambique, Tanzania, and Sudan would be at risk from intensified storms and rising sea levels, experts say.
According to the Mozambique study, the re-insurance industry has also recognised the need to increase the probability of tropical cyclones making landfall on vulnerable coasts in its risk calculations.
An average 78 million people worldwide are exposed each year to tropical cyclone wind hazard and another 1.6 million to storm surges. In terms of economic exposure, an annual average of $1,284 billion in GDP is exposed to tropical cyclones, according to the 2009 Global Assessment Report on Disaster Risk Reduction.
“Currently 10 per cent of the world’s total population and 13 per cent of its urban population live on the 2 per cent of the world’s land area that is less than 10m above sea level,” it stated. “In Africa, 12 percent of the urban population lives in this area.”
