Sea level is rising fastest along the western Gulf Coast of the United States, in Southeast Asian megacities like Bangkok and Jakarta, and across low-lying Pacific Island nations. While the global average has risen 8 to 9 inches since 1880, some of these regions are seeing rates several times higher, driven by a combination of rising oceans and sinking land.
The U.S. Gulf and Mid-Atlantic Coasts
Within the United States, the fastest sea level rise is happening along the Gulf Coast from the mouth of the Mississippi River westward, followed by the mid-Atlantic coast. The western Gulf region is projected to see 16 to 18 inches of rise above 2020 levels by 2050, nearly half a foot higher than the national average. Louisiana is a particular hotspot because the Mississippi River delta is naturally compacting, and decades of oil and groundwater pumping have accelerated the sinking.
The mid-Atlantic tells a similar story. Over the 20th century, coastal communities near Cape Hatteras, North Carolina, and along the Chesapeake Bay in Virginia experienced roughly a foot and a half of sea level rise. New York City and Miami saw about a foot, while Portland, Maine, saw only about half a foot. That dramatic variation along a single coastline comes down to geology, not just climate.
Why Some Coasts Sink While Oceans Rise
The single biggest factor creating regional differences along the U.S. East Coast is post-glacial rebound. During the last Ice Age, massive ice sheets pressed down on Canada and the northeastern U.S. like a weight on a trampoline. The land around the edges of those ice sheets, particularly the mid-Atlantic coast, bulged upward in response. When the ice melted, the process reversed: northern areas slowly bounced back up, while the mid-Atlantic began sinking. That see-saw effect is still happening today, thousands of years after the ice disappeared, and it adds inches of relative sea level rise on top of what the ocean itself is doing.
Land subsidence from human activity compounds the problem. More than 80 percent of identified land subsidence in the U.S. has been caused by groundwater extraction. When water is pumped from underground, fine-grained sediments compact and the ground surface drops permanently. This is why cities built on river deltas or soft coastal sediments are especially vulnerable.
Southeast Asia’s Sinking Megacities
Some of the most extreme relative sea level rise on Earth is happening in cities that are physically sinking into the ground. Bangkok and its surrounding provinces are subsiding at an average rate of about 7 millimeters per year, with some areas northeast of the city dropping more than 50 millimeters (about 2 inches) per year. Projections suggest subsidence rates across the region will increase beyond 9 millimeters per year in coming decades. For comparison, the global average ocean rise is currently about 3.6 millimeters per year, so the land in these areas is sinking far faster than the sea is climbing.
Jakarta faces a nearly identical situation. Parts of the city’s northern coast have sunk several meters over past decades due to relentless groundwater pumping for a population of more than 10 million. The combination of sinking land and rising seas has made flooding so severe that Indonesia is relocating its capital to higher ground on the island of Borneo. Mexico City, though not coastal, illustrates the same mechanism: centuries of groundwater extraction have caused the city to sink unevenly, cracking buildings and buckling roads.
Pacific Island Nations
Low-lying Pacific islands face a different kind of crisis. They aren’t sinking, but they sit so close to the waterline that even modest increases in sea level translate into dramatic changes in daily life. NASA’s sea level change team projects that nations like Tuvalu, Kiribati, and Fiji will experience at least 6 inches of additional rise in the next 30 years.
The practical impact is measured in flood days. Parts of Kiribati that currently see fewer than five high-tide flood events per year are projected to average 65 flood days annually by the 2050s. Areas of Tuvalu facing the same baseline could jump to 25 flood days per year. For communities where the highest ground may be only a few meters above sea level, that kind of shift threatens freshwater supplies, agriculture, and the physical habitability of entire islands.
Ocean Currents Play a Role Too
Rising seas aren’t just about melting ice and expanding warm water. Changes in ocean circulation redistribute where that water piles up. Along the U.S. East Coast, the Gulf Stream acts as a kind of barrier, and its strength directly influences coastal water levels. When the Gulf Stream weakens, water that would normally be pushed offshore instead builds up along the coast, raising local sea levels and increasing flood risk. This effect is coherent along the entire eastern seaboard, unlike wind-driven flooding, which varies from one stretch of coastline to the next.
How Fast Is the Global Rate Accelerating
The global average rate of sea level rise more than doubled from about 1.4 millimeters per year through most of the 20th century to 3.6 millimeters per year between 2006 and 2015. In 2024, NASA measured an even higher single-year rate of about 5.9 millimeters (0.23 inches), a pace that surprised researchers. That acceleration matters because it means projections based on older, slower trends underestimate what’s coming.
Under a high-emissions scenario, the IPCC projects global mean sea level could rise roughly 0.63 to 1.01 meters (about 2 to 3.3 feet) by the year 2100 relative to recent levels. If ice sheet processes that scientists have lower confidence in also contribute, the upper range stretches to 2.3 meters (7.5 feet). About 60 to 70 percent of the world’s coastline will track close to the global average, but the remaining stretch, the places already sinking or exposed to shifting currents, will see considerably more.
Which Places Face the Greatest Risk
The regions where sea level rise hits hardest share a common pattern: rising oceans meet sinking or low-lying land. River deltas are especially exposed because their soft sediments naturally compact and because they tend to attract large populations that pump groundwater. The Ganges-Brahmaputra delta in Bangladesh, the Mekong delta in Vietnam, the Nile delta in Egypt, and the Mississippi delta in Louisiana all fit this profile.
Small island developing states in the Pacific and Indian Oceans face existential risk not because their local rise rates are the highest in absolute terms, but because they have virtually no elevation buffer. A foot of rise that a city like New York can manage with seawalls and pumps can render an atoll uninhabitable. The combination of where the water is rising fastest and where people are least able to adapt is what makes sea level rise one of the most unevenly distributed consequences of a warming climate.