Wwst African countries have been urged to ensure the sustainable management of its natural resources, particularly groundwater to prevent the land from sinking further.

They have also been reminded that coastal subsidence could have devastating effects on major cities such as Accra and Lagos where population and infrastructure continue to grow. 
Land subsidence is the gradual settling or sudden sinking of the earth’s surface.

The Chairperson of the Land Subsidence International Initiative (LASII) of the United Nations Educational, Scientific, and Cultural Organisation (UNESCO), Professor Pietro Teatini, added that the Gulf of Guinea’s low-lying regions also faced a risk if subsidence was left unchecked.

"Subsidence can reach impressive numbers, affecting deltas and megacities, especially in low-lying areas like the Volta Delta.

“People along the coast may observe the water rising and think it’s just sea level rise. However, land is also sinking," he said.

Prof. Teatini was speaking at the maiden West Africa International Workshop on coastal land subsidence at the University of Ghana, Accra.

The week-long workshop is on the theme: “Coastal land subsidence in Africa: The emerging trends.”

Among issues being discussed are the rollout of Engulf project, a research programme meant to fill the knowledge gap of coastal land subsidence and relative sea-level rise along the Gulf of Guinea.

In attendance are experts from across West Africa, Europe and Asia, who would share ideas on how to address the issue of sinking coastlines which threaten communities and ecosystems along the Gulf of Guinea. 

Impact

Prof. Teatini asserted that subsidence affected not only coastal cities but also inland regions, causing extensive damage to infrastructure.

He cited global cases, including parts of Asia and North America, where such phenomenon had led to cracks in buildings and forced communities to abandon homes.

“This is why we must carefully manage groundwater to avoid repeating these same problems in West Africa," the chairman said.

Prof. Teatini cautioned that without careful management, West Africa’s coastline could face “the same damages as some Asian megacities.”

Significance

Prof. Teatini said that the LASII project would help West African countries build resilience by sharing technical expertise and resources.

“UNESCO and LASII strongly endorse the Engulf project, recognising it as fundamental for raising awareness about subsidence in coastal areas facing the Gulf of Guinea,” he said.

The project also aims to prevent the destructive consequences already seen in other regions worldwide.

Prof. Teatini further explained that LASII was established by UNESCO to address subsidence concerns through scientific research and international collaboration.

He said they were now working closely with African countries to prevent widespread subsidence in the Gulf of Guinea through a structured approach such as monitoring, understanding mechanisms, modelling, developing mitigation strategies, and continually re-evaluating progress.

Research

For his part, a Co-Chair of the Engulf project, Dr Philip Minderhoud, said while research over the years indicated rising sea levels, it did not consider land subsidence which, he said, had a faster, compounding effect in many coastal areas.

The co-chair also warned that ignoring subsidence could lead to severe consequences for West Africa.

“Sea levels are rising around the world, and can sink coastal areas. We must plan effectively for future sea levels," he said.

Dr Minderhoud described West Africa as a “question mark” in global land subsidence research, with scant monitoring on groundwater use or vertical land movement.

"Due to this, we created the Engulf project to shed light and raise awareness of land subsidence in this region,” he said.

The project team has so far installed one of two Global Navigation Satellite System (GNSS) monitoring stations at the University of Ghana to measure changes in land elevation.

The team will install the other facility later this week to provide reliable baseline data on subsidence rates across the region.