Africa – Satellite observations over three decades revealed a dramatic speedup in sea-level rise around the continent’s extensive shorelines, driven largely by the influx of water from vanishing ice sheets.
Decades of Mounting Pressure
Decades of Mounting Pressure (Image Credits: Imgs.mongabay.com)
Researchers documented a total rise of 10.25 centimeters from 1993 to 2023 across Africa’s Large Marine Ecosystems. The overall trend stood at 3.31 millimeters per year, accompanied by an acceleration of 0.11 millimeters per year squared.
Conditions sharpened after 2010. Rates jumped from 0.96 millimeters per year in the 1993-2002 period to 4.34 millimeters per year between 2013 and 2023 – a 4.54-fold increase. The year 2023 marked a peak, with record-high levels across nearly 40 percent of the surrounding waters and anomalies reaching 16.24 centimeters in some areas.
This shift established a new baseline for coastal vulnerabilities, as detailed in a study published December 15, 2025, in Communications Earth & Environment.
Melting Ice and Warming Waters Fuel the Change
Ocean mass gains from melting ice sheets in Greenland and Antarctica, along with glaciers, explained 79 to 87 percent of the rise. These contributions stemmed from rapid ice loss exceeding 430 gigatons per year in recent times
Thermosteric expansion, caused by warming seawater, accounted for the rest in most regions, while salinity increases curbed rises in others through halosteric effects. Climate patterns such as El Niño amplified extremes, particularly in 2023.
- Mass-driven rise dominated at 2.61 millimeters per year.
- Thermosteric component averaged 0.49 millimeters per year.
- Halosteric effects subtracted 0.15 millimeters per year on average.
- Land water storage shifts and atmospheric vapor added to the mass influx.
- Upper ocean heat content hit unprecedented highs, boosting expansion.
Uneven Patterns Across Key Marine Zones
Seven Large Marine Ecosystems encircle Africa, each showing distinct trends. The Red Sea experienced the swiftest advance at 3.91 millimeters per year, followed closely by the Guinea Current at 3.41 millimeters per year.
Salinity buildup in the Mediterranean tempered its rate to 2.70 millimeters per year. Other areas, including the Somali Coastal Current and Canary Current, hovered around 3.3 millimeters per year.
| Region | Trend (mm/yr) |
|---|---|
| Red Sea | 3.91 ± 0.13 |
| Guinea Current | 3.41 ± 0.05 |
| Somali Coastal Current | 3.29 |
| Mediterranean | 2.70 ± 0.06 |
These disparities heightened risks in vulnerable spots, where subsidence in deltas compounded absolute rises into relative increases of 6 to 18 millimeters per year.
Threats to Lives, Lands, and Livelihoods
Over 250 million people live along Africa’s 40,000-kilometer coastline, with more than 50 million directly exposed to intensified flooding and erosion. Cities such as Lagos, Douala, Alexandria, and Dar es Salaam faced amplified dangers from saltwater intrusion and storm surges.
Mangroves withered under salinity stress, coral reefs bleached amid heatwaves, and fisheries faltered in upwelling zones like the Benguela and Canary currents. Events tied to the 2023 El Niño displaced over a million and affected millions more through cyclones.
Adaptation demands region-specific strategies to counter these compound hazards.
Key Takeaways
- Sea-level rise around Africa quadrupled since the 1990s, reaching 4.34 mm/yr post-2010.
- Ice melt drives over 80% of the surge, with thermal expansion filling the gap.
- 2023 records signal escalating perils for ecosystems and 50+ million residents.
As pressures mount, the study underscored the need for targeted defenses. What steps should African nations prioritize? Share your views in the comments.
