Please note: there was an error with the units for this dataset that was resolved on 17.10.2022

Sea level rise is the primary mechanism by which we expect coastal flood risk to change in the UK in the future. The amount of sea level rise depends on the location around the UK and increases with higher emissions scenarios. Here, we provide the extended exploratory time-mean sea level projections to 2300, i.e. the local sea level rise experienced at a particular location, produced as part of UKCP18.

These exploratory projections show sea levels continue to increase beyond 2100 even with large reductions in greenhouse gas emissions. It should be noted that these projections have a greater degree of uncertainty than the 21st Century Projections and should therefore be treated as illustrative of the potential future changes. They are designed to be used alongside the 21st Century projections for those interested in exploring post-2100 changes. Note, that we cannot rule out substantial additional sea level rise, as on these time horizons, the potential for additional sea level rise associated with dynamic ice discharge from the West Antarctic Ice Sheet is even more uncertain.

Data is presented as the projected change (or 'anomaly') in the time-mean sea level change relative to the average value for the period 1981-2000. Values are given in centimetres and are shown on a WGS84 grid (approximately 12km) around the UK coastline.

For each grid box the time-mean sea level change projections are provided for three Representative Concentration Pathways (RCP):

• RCP2.6
• RCP4.5
• RCP8.5

A number of percentiles:

• 5th percentile
• 50th percentile
• 95th percentile

And on decadal timescales from 2010 to 2300.

The data is supplied so that each row corresponds to the combination of a RCP emissions scenario and percentile value e.g. 'RCP45_50' is the RCP4.5 scenario and the 50th percentile. This can be viewed and filtered by the field 'RCP and Percentile'. The column (fields) corresponds to each decade, the fields are named by sea level anomaly at year x, e.g. ‘2150 seaLevelAnom'.

Data is not filtered by default. Use filters to select an RCP and percentile, and then 'change style' to set which year is displayed. Use 'show table' to view all values.

For a comprehensive description of the underpinning science, evaluation and results see the UKCP18 Marine Projections Report (Palmer et al, 2018).

What are the emission scenarios?

The extended exploratory time-mean sea level projections were produced using some of the future emissions scenarios used in IPCC AR5. These are RCP2.6, RCP4.5 and RCP8.5, which are based on the concentration of greenhouse gases and aerosols in the atmosphere. RCP2.6 is a low emissions pathway, where radiative forcing peaks early and begins to fall before 2100. RCP4.5 is an intermediate 'stabilisation' pathway, where radiative forcing peaks before 2100 and begins to stabilize. RCP8.5 is a high emission pathway, where radiative forcing continues to rise beyond 2100. Further information is available in the RCP Guidance on the UKCP18 website.

What are the percentiles?

The extended exploratory time-mean sea level projections correspond to the IPCC AR5 “likely range”, which can also be interpreted as the 5th to 95th percentiles. The 5th to 95th percentiles are based on the underlying model distributions. The 50th percentile represents the central estimate amongst model projections and the 5th to 95th percentiles represent the projection range amongst models. It should be noted that there may be a greater than 10% chance that the real-world response lies outside this range.

Data source:

seaLevelAnom_marine-sim_rcp26_ann_2007-2300.nc

seaLevelAnom_marine-sim_rcp45_ann_2007-2300.nc

seaLevelAnom_marine-sim_rcp85_ann_2007-2300.nc

UKCP18 v20190315 (downloaded 04/04/2022)