African coastal cities under threat of rising sea levels 

MANY AFRICAN COUNTRIES may be looking at phenomenal and unrelenting sea-level rise as one of the distant outcomes of climate change. In reality, it is nearer than many could imagine. In fact, ignoring its impacts on a wider ramification of impacts could prove to be extremely expensive in economic and human terms in the immediate and long term. Trends in previous years, especially very recently, are a cause for alarm and call for urgent policy intervention on mitigating and remedial actions. Rise in sea-level undoubtedly shows a potential for coastal flooding —  especially in the low-lying areas — and damage to infrastructure, including seaports and airports, roads, rails, residential and commercial houses, offices, potentially disrupting trade and affecting the economy. Economic consequences can also be huge. 

Worldwide, cities on the coastline are increasingly coming under threat, warranting some desperate measures to arrest or slow down the incursion of water where feasible. In the US, for instance, New York City is one of those areas currently highly susceptible to flooding and which may lose some of its neighbourhoods to water anytime in the future. Manhattan is particularly at significant risk of increased flooding due to rising sea levels and storm surges. The low-lying coastal areas of New York City have already experienced sea level rise by about 12 inches since 1900, and are projected to rise by as much as 5.4 feet by 2100. Storms, intensified and combined with warming waters will lead to more frequent and powerful and increased coastal tidal flooding. It has been projected that, by the 2050s, 37 percent of buildings in Lower Manhattan will be at risk from storm surge, and almost 50 percent of buildings will be at risk from storm surge by 2100. By then, 20 percent of Lower Manhattan’s streets is projected to be at risk of daily flooding due to over six feet of predicted sea-level rise.

Florida’s case looks more pathetic and appears to be happening rather fast. Currently, not a few Florida cities are at risk of flooding as a result of rising sea levels and perennial storm surges. Many cities, including Miami Beach, and Fort Lauderdale, Pembroke Pines, Miramar, Plantation, Davie, St. Petersburg, Miami, and Tampa are facing significant risk of flooding due to their low elevation and proximity to the ocean. According to the Florida Economic and Demographic Research, several Florida counties, including Broward, Miami-Dade, and Pinellas, are considered to be at high risk of flooding due to sea level rise. Particularly pathetic is the case of parts of New Orleans which are already below sea level, facing the risk of being submerged. The coastal city is particularly vulnerable, sinking at a rate of two inches per year, while some areas are already 15 feet below sea level. Thus, a significant portion of the city could be underwater by 2100, according to a 2016 NASA study. Its location on a river delta increases its exposure to sea-level rise and flooding. 

Jakarta, Indonesia’s administrative capital, is already going underwater, with a lot of infrastructure becoming submerged. As at 2018, North Jakarta has sunk 2.5 metres in 10 years, continuing to sink by roughly 25 cm a year in some parts, a situation considered as more than double the global average for coastal megacities, with almost half the city now sitting below sea level. This has prompted the authorities to move the capital to another place, called Nusantara, located on the island of Borneo.

Africa’s major coastal cities include Durban and Cape Town in South Africa, Abidjan in Ivory Coast, Dakar in Senegal, Freetown in Sierra Leone, Cotonou in Benin Republic, Lomé in Togo, Accra in Ghana, Lagos in Nigeria and Luanda as Angola’s capital and Dar es Salaam in Tanzania. The physical and social stability of these coastal cities are key to their prosperity and economic survival of their respective countries. In Africa, it is particularly worrisome as many cities and administrative or commercial capitals are under the threat of ocean surge and sea-level rise. While some are slow and surreptitious, others are rapid and eventful. Mozambique’s Cyclone Idai of March 4, 2019 to March 21, 2019 destroyed some coastal cities. The cyclone Idai made landfall in Beira on the night of March. 14-15 2019, devastating Madagascar, Mozambique, Malawi and Zimbabwe. Cyclone Kenneth came a month later in April 21 to 29, 2019, causing significant destruction in coastal cities in Mozambique, particularly in Pemba and Ibo Island. The storm, which made landfall in Cabo Delgado on April 25, 2019, caused widespread damage, including the destruction of homes, roads, schools, and health centers, apart from the deaths and injuries it caused. Both Cyclones Idai and Kenneth caused widespread devastation in coastal areas of Mozambique, causing displacement, and loss of life, exacerbated by heavy rainfall, flooding, particularly in informal housing in low-lying areas. The coastal city of Beira was severely affected, with some reports suggesting up to 90 percent of its infrastructure was destroyed from infrequent high impact short term weather events in quick succession. 

In Kenya, the port city of Mombasa has been hit with slow, but long term weather events of high impact. The city of great economic status and a major source of Kenya’s revenues is endangered. Studies predict significant economic losses due to sea-level rise in Mombasa, potentially reaching millions of dollars per year. An estimated 190,000 people and $470 million in assets are vulnerable under the current exposure to a 1:100 year extreme water level for the whole of Mombasa district. According to estimates,  a 0.3-meter rise in sea level could submerge 17 percent of Mombasa City, an event that would result in devastation, rendering part of Mombasa uninhabitable. 

In Senegal, Dakar — the capital city — is not used to much rain. However, Dakar was inundated in August 2022 after it was significantly flooded in the aftermath of heavy rains that dumped 156 mm of water in two hours. That event led to widespread damage. The 2022 heavy rainfall resulted in almost 500 mm of rain over five days, causing flooding and infrastructure damage.

In the United Arab Emirates (UAE), rainfall has been a rare event. And to induce rain, Dubai’s authorities have spent $20 million — officially acknowledged — on “cloud seeding” to cause rain. Part of the “seed” invested was harvested on Tuesday, April 16, 2024. In a historic weather event, the UAE witnessed its heaviest rainfall on record in the past 75 years then, as over a year’s worth of rain fell in just a single day, within 24 hours, creating a deluge that submerged cities in the Gulf region. The heavy precipitation dominated the northern coastal strip near Dubai, Sharjah, and Abu Dhabi, reaching up to 250 mm. The record-breaking precipitation event surpasses the country’s annual average precipitation of about 100 mm. In the aftermath, with Dubai International Airport recording 164 mm of rain, the widespread flooding and significant disruption impacted infrastructure, transportation, and socio-economic activities. The damage, including disruptions at Dubai International Airport and road closures, continued into the following days. 

The flooding further raises the spectre of concerns in Dubai’s sea reclamation projects, like Palm Jumeirah as it faces several risks, including structural instability, environmental damage, and potential impacts from climate change. Reclaimed land — it has been argued — can sink or become susceptible to liquefaction during earthquakes. Moreover, when built on dredged sediments, reclaimed land is particularly less stable than natural land and can sink over time. Earthquakes can also trigger liquefaction, where the once-solid sediments turn into a fluid-like substance, causing further instability and damage to buildings and infrastructure. According to reports, the famous Palm Jumeirah, one of Dubai’s largest reclamation projects, is already actually sinking. 

Since normal coastal cities worldwide are under threat of flooding due to rising ocean level, the risks for reclaimed land are higher. This is both a fact and a reality. Fighting back water is as futile as it is foolhardy. It comes with repercussions. In the coastal area of the southwestern Nigeria, a town called Okun Alfa in Lagos State, was a thriving tourism centre until recently. Okun Alfa, formerly a popular coastal community and tourist destination known as Alpha Beach, is facing an existential threat due to rising sea levels and coastal erosion encroaching on the community. The relentless ocean surges, washing away homes, businesses, and infrastructure, are forcing residents to evacuate or repeatedly move their homes further and further back from the shoreline, as floods and sea tidal waves are constantly pounding those homes. The community’s economy, once reliant on tourism, is collapsing as the sea gradually consumes the land, which is half gone as part of it is already washed into the ocean and the entire community may soon be submerged due to the encroaching waters of the Atlantic Ocean. 

The “wonders” of land reclamation not too far from Okun Alfa, just behind the Victoria Island, is now like an extension of Victoria Island into the sea, creating one of the biggest artificial peninsulas anywhere in Africa, as well as one of the potential disaster areas of the future. Such an ambitious project is now a haven for prized estates springing up in an area very prone to boisterous sea and also to sea level rise. Incurable optimists who ignore red flags are likely to dismiss the threats to those places, arguing that the Atlantic City is immune to extreme weather events. But if Jumeirah Palm estate on a quieter sea is now sinking, how much faster will Atlantic City sink or be overrun by rising Atlantic Ocean waters? Only time will tell.

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