Transcript Regionalkonferenz der Metropolregion Hamburg

Regional climate services –
the case of Hamburg and the
Elbe estuary
Hans von Storch
Institut of Coastal Research, Helmholtz Zentrum Geesthacht
Germany
1
Knowledge market
• 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forms of knowledge (pre-scientific, outdated;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.
2
Two different construction of „climate change“ –
scientific and cultural – which is more powerful?
Cultural: „Klimakatastrophe“
Temperature
Scientific: man-made change is
real, can be mitigated to some
extent but not completely avoided
Lund and Stockholm
Storms
3
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!
4
Hamburg – storm surges
5
Sturmfluten in der Elbe
Vergangenheit
Differenz Scheitelhöhen Hamburg Cuxhaven
Storm surges in Hamburg
elevated because of modifying
the river Elbe – both coastal
defense and shipping channel
deepening
6
Case of German Bight
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.
7
Summary of knowlede about
change of storm surge heights
Significant drivers of
changing storm surge
heights
Recent changes
1967-2008
Possible
changes until
2030
Possible
changes until
2100
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
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
Global mean sea level rise
waves
See: GKSS, 2009 : Nordseesturmfluten im Klimawandel .GKSS Wissenschaftler
fassen aktuellen Forschungsstand zusammen.
8
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“)
Options for adaptation
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.
10