The data are projected extreme sea levels at approximately 2 km spacing around the UK coastline, including England, Wales, Scotland, Northern Ireland, and Isle of Man. The data were produced by the Met Office, using estimates of present-day extreme sea levels at all open-coast Coastal Flood Boundary point locations, provided by the Environment Agency and projections of 21st Century time-mean sea level change prepared at the Met Office.

Projected extreme sea level values are described for 16 different annual probabilities of exceedance (return levels), ranging from 1:1 to 1:10,000, identified in the shapefile as ‘t1’ to ‘t10000’. Confidence levels relating to the 5% and 95% lower and upper bounds of confidence are included, identified in the shapefile with the prefix ‘c1_’ and ‘c3_’ respectively, as well as the 70% confidence level identified in the shapefile with the prefix ‘c2_’.

The data were produced to put the projected future mean sea level change in the context of the present-day extremes. The data were produced by combining the best estimates of present-day extreme sea levels with projections of mean sea level change. The data covers the period from 2020 to 2100 and is available for each decade (i.e., 2020, 2030... 2100).

Further information on this dataset and UKCP18 can be found in the documentation section.