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UKCP18 21st century time-mean sea level projections around the UK for 2007-2100

Update Frequency: As Needed
Latest Data Update: 2023-03-14
Status: Ongoing
Online Status: ONLINE
Publication State: Published
Publication Date: 2018-11-26
Download Stats: last 12 months
Dataset Size: 9 Files | 458MB


The UKCP18 21st century sea level projections are provided as spatially a continuous dataset around the UK coastline. The projections are rooted in CMIP5 climate model simulations and the process-based methods described in IPCC AR5 (Church et al, 2013). The data consist of annual time series of the projected change in the time-mean coastal water level relative to the average value for the period 1981-2000. Projections are available for the RCP2.6, RCP4.5 and RCP8.5 climate change scenarios (Meinshausen et al, 2011). Nine percentiles are provided to characterise the projection uncertainty. The 5th, 50th and 95th percentiles are equivalent to the IPCC AR5 lower, central, and upper estimate of projected sea level change, based on underlying modelling uncertainty.

This dataset was updated in March 2023 to correct a minor processing error in the earlier version of the UKCP18 site-specific sea level projections relating to the adjustment applied to convert from the IPCC AR5 baseline of 1986-2005 to the baseline period of 1981-2000. The update results in about a 1 cm increase compared to the original data release for all UKCP18 site-specific sea level projections at all timescales. Further details can be found in the accompanying technical note.

Citable as:  Met Office Hadley Centre (2018): UKCP18 21st century time-mean sea level projections around the UK for 2007-2100. Centre for Environmental Data Analysis, date of citation.
Abbreviation: Not defined
Keywords: Not defined


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Data lineage:

Data provided by the UK Met Office

File Format:
Data are NetCDF formatted

Process overview

This dataset was generated by the computation detailed below.

UKCP18 regional time-mean sea level projections for the 21st Century


The UKCP18 21st Century regional time-mean sea level projections are based on CMIP5 climate model simulations of global ocean thermal expansion and global average surface temperature (GST) change. Global contributions from ice sheet surface mass balance and glaciers are related to GST following methods described in IPCC AR5 WG1 Chapter 13 (Church et al, 2013). Global sea level contributions for dynamic ice discharge for Greenland and Antarctica are based on IPCC AR5 and Levermann et al (2014), respectively. Estimates of land water storage changes follow those reported in IPCC AR5. These global components are regionalised for the UK through use of: (i) sea level fingerprints for mass components provided by Aimee Slangen and Giorgio Spada; (ii) regression relationships around the UK and across CMIP5 models for the oceanographic component; (iii) an ensemble of estimates of the relative sea level change from glacial isostatic adjustment from the NERC BRITICE_CHRONO project. Following the approach of Church et al (2013), a 100,000 sample Monte Carlo is used to provide uncertainties for regional sea level change based on the 5th and 95th percentiles of the Monte Carlo sample. Please refer to UKCP18 documentation for detailed methods.

Input Description


Output Description


Software Reference


  • units: m
  • long_name: Local time-mean relative sea level anomaly
  • var_id: seaLevelAnom
  • names: Local time-mean relative sea level anomaly
  • var_id: percentile
  • long_name: percentile
  • names: percentile

Co-ordinate Variables

  • standard_name: time
  • var_id: time
  • long_name: Time
  • names: time, Time
  • units: degrees_north
  • standard_name: latitude
  • var_id: latitude
  • names: latitude
  • units: degrees_east
  • standard_name: longitude
  • var_id: longitude
  • names: longitude
Temporal Range
Start time:
End time:
Geographic Extent

Related parties
Principal Investigators (1)