If every glacier and ice sheet on Earth melted completely, global sea level would rise by more than 195 feet (60 meters). That’s enough to submerge most coastal cities and redraw the world’s coastlines dramatically. This scenario won’t happen overnight, but understanding where all that water is locked up helps put current sea level trends into perspective.
Where the Ice Is and How Much Each Source Holds
Not all ice contributes equally. The vast majority of the world’s frozen water sits in just two places: Antarctica and Greenland. Everything else, from Alpine glaciers to Arctic ice caps, adds a relatively small share on top.
Antarctica is the heavyweight. The continent holds enough ice to raise sea levels by roughly 190 feet (58 meters) if it all melted. Within Antarctica, the West Antarctic Ice Sheet is the portion scientists worry about most. It sits on bedrock below sea level, making it vulnerable to warming ocean water that can erode it from underneath. The West Antarctic Ice Sheet alone contains enough water to raise seas by about 16 feet (5 meters).
Greenland’s ice sheet is the second largest reservoir. A complete melt there would add approximately 23 feet (7 meters) to global sea level. Greenland is already losing ice faster than Antarctica in absolute terms, partly because it sits at lower latitudes where temperatures are warmer.
Mountain glaciers and smaller ice caps around the world, from the Himalayas to Patagonia to Alaska, collectively hold enough ice to raise seas by roughly 1 to 2 feet (about 0.3 to 0.5 meters). That sounds modest next to the ice sheets, but it’s enough to threaten low-lying islands and coastlines, and these smaller glaciers are melting much faster relative to their size.
Why Melting Sea Ice Doesn’t Add Much
A common point of confusion: the Arctic sea ice that makes headlines every summer floats on the ocean. A floating object already displaces its own weight in water, so when it melts, it mostly fills the same volume it was already displacing. This is the same principle as ice cubes melting in a glass without overflowing it.
There is a small twist, though. Sea ice is made of fresh water, which is less dense than the salty ocean beneath it. When that fresh ice melts into saltwater, the resulting liquid takes up slightly more volume than the saltwater it was displacing as ice. The effect is real but minor compared to land ice. A massive glacier sliding off a continent into the sea raises levels far more than a floating ice shelf melting in place.
Thermal Expansion Adds to the Total
Melting ice isn’t the only factor. As ocean water warms, it physically expands. This thermal expansion has actually accounted for about 56% of the sea level rise observed in recent decades. A 1°C increase in average ocean temperature would, on its own, raise global sea level by nearly 3 feet (0.89 meters) purely from expansion, with no additional ice melt at all.
So the 195-foot figure from melting all ice is a floor, not a ceiling. Warmer oceans in a world with no ice would sit even higher than that number suggests.
How Fast Seas Are Rising Now
The current rate of global sea level rise is about 4.5 millimeters per year as of 2024. That’s roughly a fifth of an inch annually, which sounds small but represents a dramatic acceleration. In 1993, when satellite measurements began, the rate was about 2.1 millimeters per year. It has more than doubled in three decades.
At the current pace, seas would rise roughly 18 inches over a century. But the rate is accelerating, not holding steady. Ice loss from Greenland and Antarctica is speeding up, and ocean warming continues to compound the effect. Under high-emission scenarios, projections for Antarctica alone range from 2 to 10 feet of sea level contribution by the year 2300. The long-term consequences of high emissions extend well beyond the next century because ice sheets respond slowly. Once large-scale collapse begins, it continues for hundreds to thousands of years even if warming stops.
What a Warmer Past Tells Us
Earth has been warmer before. During the early Pliocene epoch, roughly 3 to 5 million years ago, atmospheric CO2 levels were similar to today’s concentrations. Sea levels during that period sat around 57 feet (17.5 meters) higher than present, with Antarctic ice holding substantially less volume than it does now. That era offers a rough preview of where equilibrium sea levels could eventually settle if current CO2 levels persist for millennia.
The Pliocene didn’t reach the full 195-foot scenario because not all ice melted. But it shows that even partial ice loss, sustained over long periods at CO2 levels we’ve already reached, produces sea level rise measured in tens of feet rather than inches.
What the Land Does After Ice Disappears
One counterintuitive wrinkle: when a massive ice sheet melts, the land underneath it rises. Ice sheets are extraordinarily heavy, pressing the Earth’s crust downward. Remove that weight, and the crust slowly rebounds upward, like a mattress springing back after you stand up.
This rebound doesn’t cancel out sea level rise globally. In fact, it slightly amplifies it. As the crust rises in places like West Antarctica, it pushes water out of the space the bedrock previously occupied, redistributing it into the open ocean. After a West Antarctic collapse, this crustal rebound could add roughly 3 feet (about 1 meter) of additional global sea level rise beyond the meltwater itself. Near the former ice sheet, though, local sea levels actually drop dramatically because the land rises so much and the gravitational pull of the ice mass disappears. The effects of ice loss are not spread evenly around the planet.
What 195 Feet Would Actually Look Like
A world with no ice would be unrecognizable. Florida would vanish entirely. So would Bangladesh, the Netherlands, and most of Denmark. London, Shanghai, New York, Mumbai, Tokyo, and nearly every major coastal city would be underwater. The Amazon Basin would become a massive inlet. New coastlines would form hundreds of miles inland from where they sit today.
This full scenario would take thousands of years to unfold, even under the most extreme warming. But smaller increments of that total, measured in feet rather than hundreds of feet, are plausible within centuries and would still displace hundreds of millions of people. The loss of glaciers feeding major rivers like the Ganges, Yangtze, and Indus would simultaneously create freshwater crises for billions, compounding the damage from rising seas.