Sea level rise map – which land lies below the water?

How much of a coast would be under water if the sea rose by one metre, or by five? This map answers that question visually for any coastline on Earth. Move the slider or press one of the quick buttons, and every piece of land that lies at or below the chosen level turns blue; land that is already below today's sea level, such as the polders of the Netherlands or the reclaimed land around some ports, is shown in a lighter blue so that the new flooding stands out. Search a town, use your location or click on a house or a field to read the ground height at that spot, and the panel says whether it lies above the water, below it, or so close to the line that the height model cannot tell. The level is measured from today's mean sea level, so a value of 1 m is the sea one metre higher than now; to think about a storm, add the height of a high tide or a storm surge at your coast to the long-term rise. The map is meant to show where low land is and how quickly the picture changes with each metre, not to decide whether a single house will flood. The link button saves the level and the point, so you can send exactly the same view to someone else.

How to use it

1. Choose a sea level rise with the slider or one of the quick buttons (0.5 to 10 m).
2. Search a town, press "Use my location" or zoom in on the coast you are interested in.
3. Click a house or a plot to see its ground height and whether it lies above or below the chosen level.
4. Copy the answer or share the link, which keeps the level and the point.

How accurate is it?

How exact the heights are

The heights come from Terrain Tiles, a mosaic of public height models: lidar-based models with 1–3 m vertical error in the USA and parts of Europe, and SRTM or similar radar models with typically 5–10 m error in much of the rest of the world. Radar models measure the tops of trees and buildings, so dense cities and forests look higher than the ground really is, and the slider will then show too little flooding. A point is called above or below only when the margin is more than 3 m; anything closer is shown as uncertain.

What the bathtub model leaves out

The map paints every pixel that is low enough, whether or not the sea can reach it. Dikes, sea walls, dunes and pumps keep large areas dry today, and an inland hollow far from the coast turns blue even though water would never get there; the Dead Sea basin and the Caspian depression are examples. It also ignores tides, waves, erosion, river flooding and the land itself rising or sinking, which in some deltas is faster than the sea level rise.

How much the sea is expected to rise

The IPCC's sixth assessment report (2021) gives a likely global rise by 2100, compared with 1995–2014, of about 0.3–0.6 m with low emissions and 0.6–1.0 m with very high emissions, and says a rise approaching 2 m by 2100 cannot be ruled out. Local rise differs from the global mean because land moves and ocean currents change, so national agencies publish their own figures; use those for planning.

Good to know

Forgetting the storms

Most damage happens in storms, not on calm days. A 100-year storm surge can add one to several metres on top of the mean sea level, so a house that stays dry with a 1 m rise may still flood in a storm. Add your coast's surge height to the long-term rise and look at that level too.

Reading the colour at street level

At the highest zoom each pixel of the height model is about 5 m across on lidar coasts and up to 30 m elsewhere, and the edge between blue and land is only as good as the height model. Use the map to see the pattern of low land, not to tell one side of a street from the other.

Mixing up height systems

Heights here are above mean sea level (the geoid), like the heights on topographic maps. The height a GPS or a phone shows is often above the ellipsoid and can differ by tens of metres, and local datums can differ from global mean sea level by up to a metre or so.