1 Regional climate services – the case of Hamburg and the Elbe estuary Hans von Storch Institut of Coastal Research, Helmholtz Zentrum Geesthacht Germany

2 The science-policy/public interaction is not an issue of knowledge speaks to power. The problem is not that the public is stupid or uneducated. Consensus on scientifically generated knowledge is not sufficient to derive (culturally acceptable) political consensus. The linear model does not work. The problem is that the scientific knowledge is confronted on the explanation marked with other forms of knowledge (pre-scientific, outdated; traditional, morphed by different interests). Scientific knowledge does not necessarily win this competition. Knowledge market

3 Lund and Stockholm Two different construction of climate change – scientific and cultural – which is more powerful? Cultural: Klimakatastrophe Scientific: man-made change is real, can be mitigated to some extent but not completely avoided Storms Temperature

4 Typical misunderstanding: Climate change will make northern Germany uninhabitable Flooding of North Sea coast after 5 m sea level rise – if there would be no coastal defense!

5 Hamburg – storm surges

6 Differenz Scheitelhöhen Hamburg - Cuxhaven Storm surges in Hamburg elevated because of modifying the river Elbe – both coastal defense and shipping channel deepening Sturmfluten in der Elbe Vergangenheit

7 Temporal development of intra-seasonal 99%ile of high tide levels AFTER subtraction of annual mean high tide and mean annual high tide in Esbjerg (Denmark) and Den Helder (The Netherlands) until Case of German Bight

8 Summary of knowlede about change of storm surge heights Significant drivers of changing storm surge heights Recent changes Possible changes until 2030 Possible changes until 2100 Global mean sea level riseca. 2 dmca. 1 – 2 dmca. 2 – 8 dm Meteororological short term effects (storms) noneca. 0 – 1 dmca. 1 – 3 dm Regional and local sea level change ca. 2 dmSo far unknown wavesnoneSo far unknown tidesRegionally very different So far unknown bathymetryRegionally very different So far unknown See : GKSS, 2009 : Nordseesturmfluten im Klimawandel. GKSS Wissenschaftler fassen aktuellen Forschungsstand zusammen.

Regional Climate Service 1.Analysis of cultural construct, including common exaggeration in the media. -Determination of response options on the local and regional scale: mainly adaptation but also regional and local mitigation. -Dialogue of stakeholders and climate knowledge brokers in Klimabureaus. 2.Analysis of consensus on relevant issues (climate consensus reports). 3. Description of recent and present changes. 4 Projection of possible future changes, which are dynamically consistent and possible (scenarios)

10 Technological optimization of flood protection infrastructures Besides enforcing traditional measures of coastal defense, new adaptive options need to be developed. Candidates are constructing coastal defense measures such they may at a later time further be fortified. damping of tidal energy in estuaries (Tideelbeprojekt) improved design for constructing dykes (more effective clay cover layer; increased allowance for wave overtopping) building on warfts (e.g. HafenCity) Flood proof spatial planning; building codes, such as cascading zoning for the case of defense failure, but also retreat. Options for adaptation