1. Detailed projections of coastal climate change until 2100 in N Europe ESSP conference, Beijing, 12. November 2006 Parallel 37: Sea level rise, vulnerability and impacts Hans von Storch, Katja Woth, Ralf Weisse, Burkhardt Rockel and Lidia Gaslikova GKSS Research Center, Geesthacht, Germany

2. Detailed projections of coastal climate change until 2100 in N Europe Hans von Storch, Katja Woth, Ralf Weisse, Burkhardt Rockel, and Lidia Gaslikova In a concerted effort of a series of quasi-realistic models of the regional atmosphere, the hydrodynamics of the North Sea and of the wave conditions, global climate change scenarios prepared for IPCC are downscaled to a high- resolution grid presentation of storminess, currents, water levels and wave heights in Northern Europe and particularly in the North Sea area. In this way, possible and plausible future developments are derived with an hourly time increment. The analysis of the changing conditions indicates that for most parts of Northern Europe, storminess will increase at least in the domain of the North Sea. Maximum wind speeds may increase by about 10% accordingly, storm surge heights may rise by some 20 cm in the German Bight. Adding these increases to the expected mean sea level rise, higher storm water levels in Hamburg of 60 and more cm are plausible for the end of the 21st century. In this scenario, high waves in the German Bight may grow by another 20 cm. With such expectations for the end of the century, it appears unlikely that any man-made changes in the wind conditions and related effects in coastal zones can be detected within the next couple of decades. The resulting hourly, high-resolution data set forms another of two major components of the data set COASTDAT, which is provided by the Institute for Coastal Research at GKSS to a variety of clients dealing mainly with coastal defence.

3. Overview Downscaling cascade to describe regional and local weather related variability n past decades. Usage of the same cascade to construct consistent scenarios of possible future regional and local climate conditions. Outlook

4. Katja Woth Globales Geschehen Dynamisches Downscaling Hydrodynamisches Modell der Nordseezirkulation Empirisches Downscaling Pegel St. Pauli Zusammenarbeit u. a. mit BAW, BSH, ALR Husum, FSK Norderney, Hamburg Port Authority u.a. Aber wie sieht es regional und lokal aus?

5. Extreme wind speeds over sea – simulated and recorded simuliert Beobachtet

6. Trends of annual percentiles of surge heights Weisse & Plüß, 2005 50%iles 90%iles 1958-2002

7. Changing significant waveheight, 1958-2002 wind waves

8. EU-Project PRUDENCE (Prediction of Regional scenarios and Uncertainties for Defining EuropeaN Climate change risks and Effects) Impact scenarios today scenario GCM today scenario RCMs scale globallocal Impactmodel Storm Surge Model for the North Sea: - TRIM 3D Regional Climate Models: - CLM - REMO - HIRHAM - RCAO Global Climate Model (HadAM3) IPCC A2 SRES Scenario (1961-1990 / 2071-2100)

9. RCAOHIRHAM CLM REMO5 A2 - CTL: changes in 99 % - iles of wind speed (6 hourly, DJF): west wind sector selected (247.5 to 292.5 deg)

10. Changes of annual 99-percentile wave heights averaged across a series of simulations using different models and scenarios (in m). Colouring indicates areas where signals from all models and scenarios have the same sign; red- positive, blue-negative. Weisse und Grabemann, 2006

11. Projections for the future / surge meteorological forcing: HIRHAM / RCA Differences in inter-annual percentiles of surge / A2 - CTL: HIRHAM Differences in inter-annual percentiles of surge / A2 - CTL: RCA

12. “Localisation”: From the coast into the estuary St Pauli

14. Scenarios 2030, 2085 Only the effect of changing weather conditions is considered, not the effect of water works such as dredging the shipping channel.

15. Outlook Similar challenges with assessing changes of other storms – tropical typhoons (SE Asia) and extra-tropical polar lows (N Atlantic) “Detection and Attribution” Dataset CoastDat Storms and damage New efforts underway at GKSS

16. The CoastDat-effort at the Institute for Coastal Research at GKSS (ICR@gkss)  Long-term, high-resolution reconstuctions (50 years) of present and recent developments of weather related phenomena in coastal regions as well as scenarios of future developments (100 years)  Northeast Atlantic and northern Europe  “Standard” model systems (“frozen”)  Assessment of changes in storms, ocean waves, storm surges, currents and regional transport of anthropogenic substances.  Data freely available. Applications  many authorities with responsibilities for different aspects of the German coasts  economic applications by engineering companies (off-shore wind potentials and risks) and shipbuilding company  Public information  www.coastdat.de

17. Damages and storms (Meeting of scientists and re-insurances; with Munich Re; Hohenkammer, May 2006) Consensus statement: „1. Climate change is real, and has a significant human component related to greenhouse gases. 2.Direct economic losses of global disasters have increased in recent decades with particularly large increases since the 1980s. 8.Analyses of long-term records of disaster losses indicate that societal change and economic development are the principal factors responsible for the documented increasing losses to date. 9.The vulnerability of communities to natural disasters is determined by their economic development and other social characteristics. 10.There is evidence that changing patterns of extreme events are drivers for recent increases in global losses. 13.In the near future the quantitative link (attribution) of trends in storm and flood losses to climate changes related to GHG emissions is unlikely to be answered unequivocally.“