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Regional climate services – the case of Hamburg and

the Elbe estuary

Hans von StorchInstitut of Coastal Research, Helmholtz Zentrum Geesthacht

Germany

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• 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that the scientific knowledge is confronted on the „explanation marked“ with other forms of knowledge (pre-scientific, outdated; traditional, morphed by different interests).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

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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

StormsTem

pera

tur

e

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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!

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Hamburg – storm surges

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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 ElbeVergangenheit

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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 1995.

Case of German Bight

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Summary of knowlede about change of storm

surge heightsSignificant drivers of changing storm surge heights

Recent changes 1967-2008

Possible changes until 2030

Possible changes until 2100

Global mean sea level rise ca. 2 dm ca. 1 – 2 dm ca. 2 – 8 dm

Meteororological short term effects (storms)

none ca. 0 – 1 dm ca. 1 – 3 dm

Regional and local sea level change

ca. 2 dm So far unknown So far unknown

waves none So far unknown So far unknown

tides Regionally very different

So far unknown So far unknown

bathymetry Regionally very different

So far unknown 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“)

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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