- Several large storm surge events have caused loss of life and damage to property in Europe during the past century. The most notable event occurred in 1953 when more than 2 000 people were killed, and there was massive damage to property around the coastline of the southern North Sea.
- There is strong evidence that extreme coastal water levels have increased at many locations around the European coastline. However, this appears to be predominantly due to increases in time mean local sea level at most locations rather than to changes in storm activity.
- Large natural variability in extreme coastal sea levels makes detecting long-term changes in trends difficult in the absence of good quality long observational records.
- Multi-decadal projections of changes in storms and storm surges for the European region continue to have high uncertainty. The most recent studies indicate that increases in extreme coastal water levels will likely be dominated by increases in local relative mean sea level, with changes in the meteorologically-driven surge component being less important at most locations.
What is the trend in storm surges and extreme sea levels across European seas?
Producing a clear picture of either past changes or future projections of storm surges for the entire European coast line is a challenging task because of the impact of local topographical features on the surge events. Whilst there are numerous studies for the North Sea coastline, fewer are available for the Mediterranean and Baltic Seas, although this situation is starting to improve.
The most comprehensive global studies of trends in extreme coastal sea level and storm surges examined trends from hourly tide gauge records at least for the period since 1970, and for earlier periods of the 20th century for some locations [i]. The results show that changes in extreme water levels tend to be dominated by the change in the time mean local sea level. In the north-west European region there is clear evidence of widespread increase in sea level extremes since 1970, but much less evidence of such a trend over the entire 20th century. When the contribution from time mean local sea level changes and variations in tide are removed from the recent trends, the remaining signals due to changes in storminess are much smaller or even no longer detectable.
Additional studies are available for some European coastal locations, but typically focus on more limited spatial scales. A study that examined the trend in water levels at 18 sites around the English Channel found that the rates of change in extreme water levels were similar to the rates observed for mean sea level change [ii]. However, the study also noted sizeable variations in storm surge heights, with the largest surge intensity occurring in the late 1950s. This large natural variability makes it difficult to detect changes in the rate of change in water level extremes. A similar conclusion, that the change in annual maximum sea levels are increasing at a rate not significantly different from the observed increase in mean sea level, was found in separate analyses for Newlyn in the UK for the period 1915–2005 [iii] and for 73 tide gauges along the Atlantic and Mediterranean coastlines in southern Europe [iv]. In contrast, significant increases in storm surge height during the 20th century were found along the Estonian coast of the Baltic Sea [v].
In conclusion, whilst there have been detectable changes in extreme water levels around the European coast line, most of these are dominated by changes in time mean local sea level. The contribution from changes in storminess is currently small in most European locations and there is little evidence that any trends can be separated from long-period natural variability [vi].
Future projections in storm surges can be made using either dynamic or statistical modelling of storm surge behaviour driven by the output of general circulation climate models [vii]. The uncertainty in future projections of storm surges remains high and is ultimately linked to the uncertainty in future mid-latitude storminess changes. This is an area where current scientific understanding is advancing quickly as climate model representations of aspects of northern hemisphere storm track behaviour are showing improvements associated with, for instance, greater ocean and atmosphere resolution [viii]. However, the newest global climate models have not yet, typically, been downscaled to suitably fine scales and used in studies of future storm surges.
Several climate modelling studies have projected changes in storm surge height and frequency for the 21st century. The limited number of studies that separate out any long-term climate change signal from multi-decadal climate variability suggests that changes in atmospheric storminess are likely to be less important than increases in mean local sea level. Based on the RCP4.5 scenario, recent studies estimate increases in the frequency of flooding events by more than a factor of 10 at many European locations and reaching between 100 and 1000 at some European locations [ix]. These numbers should be considered with caution because in many cases, and from a protection perspective, it is more instructive to look at the change in the height of a given return period event rather than the change in frequency of a given height of event. Large changes in flood frequency mean that what is an extreme event today may become the norm by the end of the century at some locations. However, for any particular location it is important to look in detail at the change in protection height that might be required. Where the flood frequency curve is very flat the increases might be modest. Where the flood frequency curve is steeper larger increases in protection height or alternative adaptations might be needed.
Two recent studies on future changes in surge magnitude in the North Sea region addressed some of the deficiencies in earlier studies by using ensemble simulations of climate models to drive a surge model of the North Sea for the period 1950–2100. One study found no significant change in the 1 in 10 000 year return values of storm surges along the Dutch coastline during the 21st century [x]. The other study projected small changes in storm surge heights for the 21st century around much of the UK coastline. Most of these changes were positive but they were typically much less than the expected increase in time mean local sea level over the same time period [xi]. However, larger increases in storm surge for this region during the 21st century cannot yet be ruled out.
A study on the Mediterranean region projected a reduction in both the number and frequency of storm surge events during the 21st century [xii]. A study on the Baltic Sea projected increases in extreme sea levels over the 21st century that were larger than the time mean local sea-level rise for some future scenarios simulated by some of the climate models used [xiii]. The largest changes in storm surge height were in the Gulf of Finland, Gulf of Riga and the north-eastern Bothnian Bay. A study on storm surges around the coast of Ireland projected an increase in surge events on the west and east coasts but not along the southern coast [xiv]. However, not all of the changes were found to have a high statistical significance.
At some locations, such as Hamburg, local changes in bathymetry caused by erosion, sedimentation and waterworks can have a much larger impact than climate change [xv]. Finally, recent work has shown that sea-level rise may also change extreme water levels by altering the tidal range. The tidal behaviour is particularly responsive in resonant areas of the Bristol Channel and Gulf of St. Malo (with large amplitude decreases) and in the southeastern German Bight and Dutch Wadden Sea (with large amplitude increases). These substantial future changes in the tides could have implications, for instance, for estimating requirements for flood defences [xvi].
[i] Philip L. Woodworth and David L. Blackman, “Evidence for Systematic Changes in Extreme High Waters since the Mid-1970s,” Journal of Climate 17, no. 6 (March 2004): 1190–97, doi:10.1175/1520-0442(2004)017<1190:EFSCIE>2.0.CO;2; Melisa Menéndez and Philip L. Woodworth, “Changes in Extreme High Water Levels Based on a Quasi-Global Tide-Gauge Data Set,” Journal of Geophysical Research 115, no. C10 (October 8, 2010), doi:10.1029/2009JC005997; Øystein Hov et al., Extreme Weather Events in Europe: Preparing for Climate Change Adaptation (Oslo: Norwegian Meteorological Institute, 2013), http://www.dnva.no/binfil/download.php?tid=58783.
[ii] Ivan Haigh, Robert Nicholls, and Neil Wells, “Assessing Changes in Extreme Sea Levels: Application to the English Channel, 1900–2006,” Continental Shelf Research 30, no. 9 (May 2010): 1042–55, doi:10.1016/j.csr.2010.02.002.
[iii] Isabel B. Araújo and David T. Pugh, “Sea Levels at Newlyn 1915–2005: Analysis of Trends for Future Flooding Risks,” Journal of Coastal Research 24 (July 2008): 203–12, doi:10.2112/06-0785.1.
[iv] Marta Marcos et al., “Changes in Storm Surges in Southern Europe from a Regional Model under Climate Change Scenarios,” Global and Planetary Change 77, no. 3–4 (June 2011): 116–28, doi:10.1016/j.gloplacha.2011.04.002.
[v] Ü. Suursaar, T. Kullas, and R. Szava-Kovats, “Wind and Wave Storms, Storm Surges and Sea Level Rise along the Estonian Coast of the Baltic Sea,” WIT Transactions on Ecology and Environment 127 (November 17, 2009): 149–60, doi:10.2495/RAV090131.
[vi] J. A. Church et al., “Sea-Level Change,” in Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change, ed. T. F. Stocker et al. (Cambridge, United Kingdom and New York, NY, USA: Cambridge University Press, 2013), Chapter 13, http://www.climatechange2013.org/report/full-report/.
[vii] Jason A. Lowe et al., “Past and Future Changes in Extreme Sea Levels and Waves,” in Understanding Sea-Level Rise and Variability, ed. John A. Church et al. (Oxford, UK: Wiley-Blackwell, 2010), 326–75, http://doi.wiley.com/10.1002/9781444323276.ch11.
[viii] Adam A. Scaife et al., “Climate Change Projections and Stratosphere–troposphere Interaction,” Climate Dynamics 38, no. 9–10 (May 27, 2011): 2089–97, doi:10.1007/s00382-011-1080-7; Hov et al., Extreme Weather Events in Europe: Preparing for Climate Change Adaptation.
[ix] Church et al., “Sea-Level Change.”
[x] A. Sterl et al., “An Ensemble Study of Extreme Storm Surge Related Water Levels in the North Sea in a Changing Climate,” Ocean Science 5, no. 3 (September 18, 2009): 369–78, doi:10.5194/os-5-369-2009.
[xi] J. A. Lowe et al., UK Climate Projections Science Report: Marine and Coastal Projections (Exeter, UK: Met Office Hadley Centre, 2009), http://ukclimateprojections.defra.gov.uk/media.jsp?mediaid=87905&filetype=pdf.
[xii] Marcos et al., “Changes in Storm Surges in Southern Europe from a Regional Model under Climate Change Scenarios.”
[xiii] H. E. Markus Meier, “Baltic Sea Climate in the Late Twenty-First Century: A Dynamical Downscaling Approach Using Two Global Models and Two Emission Scenarios,” Climate Dynamics 27, no. 1 (April 11, 2006): 39–68, doi:10.1007/s00382-006-0124-x.
[xiv] Shiyu Wang et al., “The Impact of Climate Change on Storm Surges over Irish Waters,” Ocean Modelling 25, no. 1–2 (2008): 83–94, doi:10.1016/j.ocemod.2008.06.009.
[xv] Hans von Storch and Katja Woth, “Storm Surges: Perspectives and Options,” Sustainability Science 3, no. 1 (2008): 33–43, doi:10.1007/s11625-008-0044-2.
[xvi] M.D. Pickering et al., “The Impact of Future Sea-Level Rise on the European Shelf Tides,” Continental Shelf Research 35 (March 2012): 1–15, doi:10.1016/j.csr.2011.11.011.
Indicator specification and metadata
- Surge height
- metre (m)
Policy context and targets
In April 2013 the European Commission presented the EU Adaptation Strategy Package (http://ec.europa.eu/clima/policies/adaptation/what/documentation_en.htm). This package consists of the EU Strategy on adaptation to climate change /* COM/2013/0216 final */ and a number of supporting documents. One of the objectives of the EU Adaptation Strategy is Better informed decision-making, which should occur through Bridging the knowledge gap and Further developing Climate-ADAPT as the ‘one-stop shop’ for adaptation information in Europe. Further objectives include Promoting action by Member States and Climate-proofing EU action: promoting adaptation in key vulnerable sectors. Many EU Member States have already taken action, such as by adopting national adaptation strategies, and several have also prepared action plans on climate change adaptation.
The European Commission and the European Environment Agency have developed the European Climate Adaptation Platform (Climate-ADAPT, http://climate-adapt.eea.europa.eu/) to share knowledge on observed and projected climate change and its impacts on environmental and social systems and on human health; on relevant research; on EU, national and subnational adaptation strategies and plans; and on adaptation case studies.
No targets have been specified.
Related policy documents
Climate-ADAPT: Mainstreaming adaptation in EU sector policies
Overview of EU sector policies in which mainstreaming of adaptation to climate change is ongoing or explored
Climate-ADAPT: National adaptation strategies
Overview of activities of EEA member countries in preparing, developing and implementing adaptation strategies
DG CLIMA: Adaptation to climate change
Adaptation means anticipating the adverse effects of climate change and taking appropriate action to prevent or minimise the damage they can cause, or taking advantage of opportunities that may arise. It has been shown that well planned, early adaptation action saves money and lives in the future. This web portal provides information on all adaptation activities of the European Commission.
EU Adaptation Strategy Package
In April 2013, the European Commission adopted an EU strategy on adaptation to climate change, which has been welcomed by the EU Member States. The strategy aims to make Europe more climate-resilient. By taking a coherent approach and providing for improved coordination, it enhances the preparedness and capacity of all governance levels to respond to the impacts of climate change.
Methodology for indicator calculation
Trends in extreme sea level and storm surges are available at many coastal locations from hourly tide gauge records.
Methodology for gap filling
No methodology references available.
Data sets uncertainty
Producing a clear picture of either past changes or future projections of storm surges for the entire European coast line is a challenging task because of the impact of local topographical features on the surge events. Whilst there are numerous studies for the North Sea coastline, fewer are available for the Mediterranean and Baltic Seas, although this situation is starting to improve. The uncertainty in future projections of storm surges remains high and is ultimately linked to the uncertainty in future mid-latitude storminess changes. This is an area where current scientific understanding is advancing quickly.
No uncertainty has been specified
No stable data source identified
provided by Unspecified
Typology: Descriptive indicator (Type A - What is happening to the environment and to humans?)
- CLIM 045
Contacts and ownership
EEA Contact InfoHans-Martin Füssel
EEA Management Plan2013 2.0.1 (note: EEA internal system)
Frequency of updates
For references, please go to http://www.eea.europa.eu/data-and-maps/indicators/storms-and-storm-surges-in-europe-1/assessment-1 or scan the QR code.
PDF generated on 24 Apr 2017, 09:58 PM