Coastal communities face a double challenge as not only do ocean levels rise due to climate change, but the ground beneath many coastal cities is sinking—sometimes nearly three times faster than the global average sea level rise.
- Coastal land sinking accelerates effective sea-level rise nearly 3x global average.
- Heavy groundwater pumping and urban development major subsidence drivers.
- Effective groundwater management can slow or stop sinking in some areas.
What happened
Researchers from the Technical University of Munich and Tulane University have found that many coastal cities are experiencing land subsidence, which when combined with rising ocean levels, leads to a much higher relative sea-level rise than previously estimated. Their study shows an average increase of about 6 millimeters per year in heavily populated coastal areas, significantly outpacing the global coastline average of 2.1 millimeters per year.
This accelerated sea level rise is primarily caused by the sinking ground beneath cities and towns, driven by factors including heavy groundwater pumping, oil and gas extraction, sediment compaction in river deltas, the weight of expanding urban infrastructure, and natural geological shifts such as tectonic movements and postglacial rebound.
Why it feels good
Understanding that land subsidence strongly influences local sea-level changes helps communities and policymakers respond more effectively to the threat of flooding and coastal damage. By recognizing the specific human activities that contribute to sinking ground, such as groundwater extraction, cities can take direct and actionable steps to reduce subsidence rates through better water management and regulation.
For example, Tokyo once suffered dramatic sinking but has managed to largely curb this through careful groundwater regulation, showing that positive change is possible. This knowledge empowers coastal populations to protect their homes and infrastructure, reducing risks and promoting sustainability.
What to enjoy or watch next
Keep an eye on initiatives and innovations in groundwater management and coastal urban planning aimed at mitigating subsidence and adapting to rising seas. Technologies and policies that improve aquifer recharge or establish stricter controls on water use will be critical in slowing down sinking ground in vulnerable cities worldwide.
Further scientific studies and updates from coastal research institutes will continue to shed light on local variations in subsidence and sea level rise, helping governments prioritize actions and investments. Watching the progress in cities like Jakarta, Bangkok, and others facing extreme rates of sinking can offer valuable lessons on effective coastal resilience.