- Mean sea level around the UK has risen by about 12–16cm since 1900.
- When vertical land movement is included, the net rate of sea-level rise is slightly higher in the south of England and slightly lower in some parts of Scotland.
- At many locations, extreme sea levels that exceed critical flood-thresholds are being experienced more frequently than in the past, due to mean sea-level rise.
High evidence, high agreement
There is high confidence in observational evidence for mean sea levels and sea-level extremes. There is now firm evidence that the rate of sea level rise (both for the UK and globally) was higher overall in the 20th century than the 19th.
- For London, the central estimate projection of sea-level rise for 2100 ranges from 0.45–0.78m, depending on the greenhouse gas emissions scenario. Estimates for other capital cities are: Cardiff 0.43–0.76m; Belfast 0.26–0.58m and Edinburgh 0.23–0.54m.
- Increases in future extreme sea levels and flooding will be driven by mean sea-level changes, rather than changes in storm surges.
Medium evidence, high agreement
The UKCP18 sea level projections are a considerable improvement over previous outputs, with better representation of ice sheet processes, improved ‘downscaling’ for the UK, and a more reliable estimate of the pattern of sea-level change caused by the Earths’ elastic response to the last de-glaciation.
- Quantifying and constraining high-end scenarios through a better understanding of dynamic ice processes (and their controlling factors).
- Translating updated sea-level science into resilience planning (e.g., to ensure SMPs are realistic and sustainable in economic, social, and environmental terms).
- Understanding how the storm track (position, strength) and its influence on storm surges and extreme water levels will change, with coupling CMIP6 models to storm surge and wave models a priority.