20 Cities Most at Risk From Rising Sea Levels

Built across low-lying alluvial marshes along the Savannah River, Georgia's oldest city faces increasingly frequent sunny-day tidal flooding. As of 2026, NOAA sensors at nearby Fort Pulaski track local sea levels rising at roughly 3.6 millimeters per year.

Operational since 1982, the Thames Barrier has closed more than 220 times to shield 1.4 million Londoners and 320 billion pounds of property from North Sea storm surges. Glacial isostatic adjustment causes southeastern Britain to sink about 1.5 millimeters annually.

Constructed over centuries of delta sedimentation and 20th-century land reclamation, western Osaka sits beneath the high-water mark of Osaka Bay. Typhoon Jebi in 2018 flooded Kansai International Airport with a 3.3-meter storm surge, leading Japan to reinforce its arched tsunami floodgates and coastal seawalls.

Founded on drained peat bogs and polders behind the North Sea Canal, Amsterdam relies on an intricate network of sluices, pumping stations, and IJsselmeer dikes. As of 2026, the Dutch Delta Programme invests over 1.5 billion euros annually to raise flood defenses against accelerating North Sea thermal expansion.

Located in the Ganges-Brahmaputra delta north of the Bay of Bengal, Kolkata depends on the Sundarbans mangrove forest to absorb cyclone energy. Rapid wetland loss and colonial-era drainage constraints leave low-lying wards exposed when severe storms like Cyclone Amphan and Cyclone Remal drive tidal water inland.

Home to more than 18 million people at the apex of the Pearl River Delta, Guangzhou sits where three major rivers meet tidal estuaries from the South China Sea. Economists estimate that without expanded sponge-city retention basins and tidal gates.

Hurricane Sandy in 2012 pushed a 14-foot storm surge into Lower Manhattan, flooding subway tunnels and cutting power to 2 million residents. As of 2026, the city is constructing the 1.45-billion-dollar East Side Coastal Resiliency floodwall system to protect vulnerable neighborhoods from projected 2050 sea rise.

Eighteenth- and nineteenth-century reclamation projects joined seven separate islands into modern Mumbai, leaving vast neighborhoods barely above Arabian Sea high tide. When summer monsoon downpours coincide with 4.5-meter spring tides along Marine Drive.

More than 21 million residents live across Lagos Island, Victoria Island, and mainland settlements bordering the Atlantic Ocean and Lagos Lagoon.Engineers built the 8.5-kilometer Great Wall of Lagos revetment using 100,000 five-ton concrete accropodes to shield the Eko Atlantic district.

Metro Manila sits on a narrow alluvial plain wedged between Manila Bay and Laguna de Bay. Satellite radar interferometry shows coastal municipalities like Navotas and Malabon subsiding nearly four times faster than global sea level rise, allowing Western Pacific typhoon surges to overtop neighborhood seawalls.

After the North Sea flood of 1953, the Netherlands built the Delta Works, anchored in Rotterdam by the Maeslantkering storm surge barrier. Its two hollow steel arms, each as long as the Eiffel Tower, swing shut automatically whenever North Sea water levels threaten to rise 3 meters above normal high tide.

Founded by Alexander the Great in 331 BC, Egypt's second-largest city sits on a narrow limestone ridge between the Mediterranean Sea and Lake Mariout. Upstream dams trap Nile silt that once replenished the coast, forcing authorities to ring the 15th-century Citadel of Qaitbay with thousands of concrete wave-breakers.

Built on timber pilings driven into mudbanks across the Venetian Lagoon, Venice has lost roughly 30 centimeters of elevation relative to the Adriatic Sea since 1897. Since entering service in 2020, the 6-billion-euro MOSE barrier system has repeatedly raised its yellow steel floodgates to keep St. Mark's Square dry.

Flanked by the Mississippi River, Lake Pontchartrain, and vanishing Gulf of Mexico wetlands, New Orleans loses natural storm buffer as Louisiana sheds a football field of coastal marsh every 100 minutes. A 14.5-billion-dollar perimeter of levees, floodwalls.

Sitting at the mouth of the Yangtze River on the East China Sea, Shanghai subsided by more than 2 meters during the 20th century before strict groundwater pumping caps and aquifer recharge wells slowed the sink rate. Today over 500 kilometers of concrete floodwalls line the Huangpu River along the Bund and Pudong.

Unlike cities that can block the ocean with seawalls alone, Greater Miami rests on honeycomb-like limestone that allows saltwater to seep beneath barriers during autumn King Tides. Miami Beach has invested over 500 million dollars elevating roads.

Woven around the Saigon River and Mekong Delta canals, Vietnam's economic hub is sinking by 1 to 2 centimeters per year due to heavy construction loads and aquifer depletion. High tides from the South China Sea regularly combine with monsoon runoff to flood urban districts home to over 9 million residents.

Located on the flat Chao Phraya River delta just north of the Gulf of Thailand, Bangkok sits an average of only 1.5 meters above mean sea level. After catastrophic floods in 2011, the city expanded giant underground drainage tunnels.

Surrounded by the Buriganga, Turag, and Balu rivers in the low-lying Bengal Delta, Dhaka absorbs both Himalayan snowmelt from upstream and displaced coastal families fleeing saltwater intrusion along the Bay of Bengal. Even a 50-centimeter sea level rise threatens to submerge 11 percent of Bangladesh's coastal land.

Nowhere on Earth faces a steeper combination of land subsidence and sea level rise than coastal Jakarta, where unregulated well pumping drops northern neighborhoods by up to 15 centimeters a year. Around 40 percent of the city sits below the Java Sea.