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Coastal — relative sea level

Page Last modified 19 Nov 2021
3 min read
More than one third of the European population lives in coastal regions. Low-lying countries, islands and communities know from experience that rising sea levels are a major climate hazard. Higher relative sea levels and corresponding storm surges threaten property, infrastructure and lives. They can lead to coastal erosion and make surface water and groundwater unusable through saltwater intrusion, with knock-on effects for agriculture and coastal and land ecosystems. Local sea level rise can be strongly affected by human activities, such as groundwater extraction or soil compaction from buildings. Understanding all this is crucial not only for coastal planning, ecosystem management and protection but also for putting in place measures to protect transport, energy and other infrastructure.

Key messages


  • Globally, mean sea levels — the height of sea water relative to land — have been rising for more than a century, with accelerating rates in recent decades due to warming oceans and melting glaciers and ice sheets.
  • The relative sea level of Europe’s seas will continue to rise throughout this century under all emissions scenarios. Under a high-emissions scenario, the rise is expected to be greater than 0.60 m along most of the European coastline (with the exception of the northern Baltic Sea and the northern Atlantic coasts).

Relative sea level rise 

Definition

The relative sea level rise index represents the changes in the height of sea water relative to land with respect to the average conditions over a reference period. The index includes geophysical sources that drive long-term changes, such as ice components, ocean-related components, land water storage and glacial isostatic adjustment, but it does not account for local subsidence due to human activities. The index can be calculated from the sea level height derived from global and regional climate models, including ocean, atmosphere, land and cryosphere components.

Index factsheet (ETC/CCA Technical Paper): Relative sea level rise

Relevance

The index provides crucial information for adaptation planning in coastal areas, including regional and urban planning, transport, energy and other infrastructure planning, and ecosystem management and protection.

Past and projected changes

Most European coastal regions have experienced increases in relative sea levels as measured by tide gauges, but with substantial regional differences. However, sea levels relative to land along the northern Baltic Sea coast and, to a lesser extent, the northern Atlantic coast are decreasing because land levels are still rising as a result of post-glacial rebound since the last ice age.

The relative sea level of European seas is projected to increase further under all emissions scenarios. The median increase of relative sea level by 2100 under the high-emissions scenario (representative concentration pathway (RCP)8.5) is expected to be greater than 0.60 m with respect to the current level along most of the European coastline. The main exceptions are the northern Baltic Sea and the northern Atlantic coasts, where sea level relative to land is expected to rise more slowly than elsewhere or even to decrease.

Note that the application of this index at the regional and local levels requires the integration of index information with regional information on land subsidence and coastal protection infrastructure.

Further information (European Climate Data Explorer): Mean relative sea level, 2070-2100

Further information (EEA indicator assessment): Global and European sea level rise

Past trends and projected changes for global mean sea level

Time series sea level

Notes:   The left panel depicts the rise in global mean sea level from 1880 to 2019 based on two data sources, relative to the average level for the period 1993-2012. The grey line shows sea level anomalies from 1900 to 2015 based on a hybrid sea level reconstruction, whereas the black line shows the filtered sea level anomalies from 1993 to 2019 based on satellite observations. The right panel shows projections of global mean sea level until 2100 (relative to the period 1986-2005) for the low-, medium- and high-emissions scenarios (RCP2.6, RCP4.5 and RCP8.5).

Sources: Time Series of Mean Sea Level Trends over Global Ocean; An ensemble approach to quantify global mean sea-level rise over the 20th century from tide gauge reconstructions; IPCC AR6 Sea-Level Rise Projections

Past trends and projected changes in relative sea level across Europe

Past trend sea level

Notes:   The arrows show the trends in relative sea level at selected European tide gauge stations since 1970. The background colours show the median of model projections of European sea level change for 2081-2100 for the high-emissions scenario (RCP8.5).

Sources: Permanent service for mean sea level (PSMSL); IPCC AR6 Sea-Level Rise Projections 

   

Chapters of the Europe's changing climate hazards report

  1. Heat and cold

  2. Wet and dry

  3. Wind

  4. Snow and ice

  5. Coastal

  6. Open ocean

                                                                               

Back to main page of the report

Related content

Related briefings

Briefing Europe’s changing climate hazards — about the report Europe’s changing climate hazards report lets users explore the latest data on 32 climate hazard indices. It provides the big picture and also the detailed information needed for smarter decision-making to prevent the worst impacts of climate change from affecting communities and regions across Europe. Here, we show how information can help Europe tackle the hazards created by man-made climate change.
Briefing What will the future bring when it comes to climate hazards? - Overview A carefully selected set of indices covering the main climate-related hazards for Europe has been put together from available data sources by experts in the field. These 32 indices are organised according to 16 hazards and are grouped into six categories consistent with the ‘climatic impact drivers’ adopted in the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report. These categories and the key take-home messages from the EEA’s interactive report on Europe’s changing climate hazards are found below.

Related data

External Data Spec Time Series of Mean Sea Level Trends over Global Ocean The sea level ocean monitoring indicator is derived from the DUACS delayed-time (DT-2018 version) altimeter gridded maps of sea level anomalies based on a stable number of altimeters (two) in the satellite constellation. These products are distributed by the Copernicus Climate Change Service and are also available in the CMEMS catalogue (SEALEVEL_GLO_PHY_CLIMATE_L4_REP_OBSERVATIONS_008_057). The mean sea level evolution estimated in the global ocean is derived from the average of the gridded sea level maps weighted by the cosine of the latitude. The annual and semi-annual periodic signals are adjusted and the time series is low-pass filtered. The curve is corrected for the effect of the Glacial Isostatic Adjustment using the ICE5G-VM2 GIA model (Peltier, 2004).
External Data Spec IPCC SROCC data on sea level rise This data archive comprises all data underlying figures and maps in Chapter 4 (Sea Level Rise and Implications for Low Lying Islands, Coasts and Communities) of the Special Report on the Ocean and Cryosphere in a Changing Climate published in 2019.

Related publications

See also

Page National and transnational climate atlases in Europe Many European countries have developed national ‘climate atlases’ (or ‘climate portals’) with spatially explicit information on past and projected climate change. These atlases inform the development and implementation of climate change adaptation plans and strategies, and provide complementary information to pan-European sources, including the indices presented in the Europe’s changing climate hazards report and the European Climate Data Explorer. The national atlases often use more detailed models and observations, and they can contextualise information on the changing climate in terms of regional environmental and socio-economic conditions in the local language(s).
Folder Open ocean From this page you can access all the indices related to Open ocean.
Folder Coastal From this page, you can access all indices related to coastal hazards.
Folder Snow and ice From this page, you can access all the indices related to snow and ice hazards.
Folder Wind From this page, you can access all indices related to wind hazards.
Folder Wet and dry From this page, you can access all indices related to wet and dry hazards.
Folder Heat and cold From this page, you can access all indices on Heat and cold hazards.
Organisation Permanent service for mean sea level (PSMSL) PSMSL is the global data bank for long term sea level change information from tide gauges and bottom pressure recorders.

Permalinks

Geographic coverage

Temporal coverage

For references, please go to https://www.eea.europa.eu/publications/europes-changing-climate-hazards-1/coastal/coastal-relative-sea-level or scan the QR code.

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