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Sea level rise

'Sea level rise' describes the phenomenon of increases in the level of the world's seas and oceans. Sea levels do not rise by the same amount from one part of the world to another and are affected by a range of factors at the global, regional and local scales.

In detail

Increasing temperatures result in sea level rise by the thermal expansion of water and through the addition of water to the oceans from the melting of ice sheets.

There is some uncertainty about the rate of future ice sheet melt and its contribution to sea level rise. However the IPCC Fifth Assessment Report (AR5) states that "Global mean sea level will continue to rise during the 21st century.... the rate of sea level rise will very likely exceed that observed during 1971 to 2010 due to increased ocean warming and increased loss of mass from glaciers and ice sheets."

UKCP09 also provides a High++ scenario, which includes possible additional contributions to sea level rise from accelerated ice sheet dynamics. The upper end of the High++ scenario range provides a plausible but highly uncertain and very unlikely scenario for sea level rise. This High++ scenario should be used for worst case and long term contingency planning rather than day-to-day investment decision-making.

Find out more

 

  • The UKCP09 Marine & Coastal Projections report includes discussion of what determines sea level in section 3.1 and describes the approach adopted in UKCP09 in section 3.2.
  • Key findings about projections of sea level change are summarised in the UKCP09 Briefing report.
  • More details about the projections of absolute changes in sea level around the UK can be found in section 3.3 of the UKCP09 Marine & Coastal Projections report, including tables, figures and plume plots

Projections of relative sea level change are available for each UK capital city and are available in the Maps & key findings selector.

  • More details about the projections of relative changes in sea level around the UK can be found in section 3.5 of the UKCP09 Marine & Coastal Projections report, including a table, map and plume plots.
  • Case studies have been developed to examine how the UKCP09 Marine & Coastal Projections might be used. They should not be interpreted as a best practice method for using UKCP09, but as one way of using the outputs.
  • For an overview of the High++ scenario, go to section 6.2 of the UKCP09 Briefing report, with more detail provided in section 1.3 of the UKCP09 Marine & Coastal Projections report.
  • For a full description, go to section 3.2 of the UKCP09 Marine & Coastal Projections report. An example of an application of the High++ scenario is provided by the Thames Estuary 2100 case study in section 7 of the Marine & Coastal Projections report.