UK-wide exposure at each scenario

Of UK postcodes with elevation data, this many would fall at or below each sea level threshold:

Important caveats

This tool is elevation-based only. It tells you whether a postcode's elevation sits below a given threshold, not whether it will actually flood or be inundated. Real flood risk depends on many things this tool doesn't know about:

  • Coastal defences (sea walls, managed realignment, tidal barriers like the Thames Barrier)
  • River and drainage networks (a postcode 50 m above sea level can still flood from a river)
  • Local geology and soil (clay, chalk, peat all behave very differently)
  • Tide and storm surge (which add metres above baseline sea level in extreme events)

For authoritative UK flood risk data, use the Environment Agency's long-term flood risk service (England) or the equivalent for Scotland, Wales and Northern Ireland.

About the sea level rise scenarios

The thresholds in this tool (0.5 m, 1 m, 2 m, 5 m, 10 m) span from already likely by 2100 (around 0.5–1 m under moderate emissions scenarios per the IPCC AR6 report) through to long-term multi-century scenarios of 5–10 m or more if polar ice sheets destabilise. The 10 m figure is a useful upper bound but wouldn't happen within most lifetimes.

Why this still useful

Elevation is the single most important factor in long-term sea level exposure. A postcode at 2 m is structurally more exposed than one at 30 m, regardless of defences. This tool gives you an honest first-pass view based on the one piece of the puzzle we can measure precisely for every postcode in the country.