365 Days of Climate Awareness 237 – Lagos, and other sinking cities

Nigeria’s Hydrological Services Agency (NIHSA), among other functions, tracks and predicts river levels in the country and has regularly predicted flooding in the commercial capital Lagos in recent years. In fact the city is sinking, due to ground water removal as well as sea level rise. This makes Lagos one of several cities worldwide in increasing danger of inundation due to the combined influence of global warming-related ocean level rise. In Lagos’ case specifically, rapid development and removal of sand without consideration for subsidence and erosion have made the threat from river flooding worse.

Following is a list, per the World Economic Forum, of the eleven cities at greatest risk of being lost:

• Jakarta, Indonesia (-17 cm/6.7 in per year due to groundwater pumping): northern zone could be underwater by 2050
• Lagos, Nigeria (coastal erosion due to rapid development and sand mining): could be uninhabitable by 2100
• Houston, Texas (-5.1 cm/2 in per year due to groundwater pumping)
• Dhaka, Bangladesh: 18% of the entire country of Bangladesh could be underwater by 2050
• Venice, Italy (-0.2 cm/0.08 in per year): city is partly underwater already
• Virginia Beach, Virginia: fastest sea-level rise on US east coast, possible 3.7 m/12 foot increase by 2100
• Bangkok, Thailand (-1 cm/0.39 in per year): could be below sea level by 2030
• New Orleans, Louisiana (-5.1 cm/2 in per year): could be underwater by 2100 (parts are already below sea level)
• Rotterdam, the Netherlands: 90% of the city is below sea level already
• Alexandria, Egypt: predicted sea level rise in eastern Mediterranean of 61 cm/2 ft by 2100
• Miami, Florida: predicted to be underwater by 2100

Houston during Hurricane Harvey, 2017.

Miami under a king tide.

Venice flooded.

The seawall of Rotterdam.

The MOSE barrier at Venice.

Each of these cities faces individual challenges in terms of causes of local sea-level rise (groundwater or otherwise), available resources and political will. In the case of Lagos, improved dredging of local river channels to reduce flooding is one helpful, and comparatively simple, remediation. In the cases of Jakarta and Houston, reducing groundwater use appears to be unlikely. A large seawall exists in Rotterdam, and one is being built, slowly, around Venice. In most cases, however, remediation might be difficult or impossible.

Tomorrow: introduction to Morocco.

Be brave, and be well.