Engineering Adaptation Strategies and Infrastructure Design Requirements to Deal with Climate Uncertainty –

Uncertainty, Certainty (and the Case of Coastal Defense)

Hans von StorchInstitute of Coastal Research

Helmholtz Zentrum Geesthachtund

Klimacampus Hamburg

6th International Conference on Water Resources and Environment Research (ICWRER) Koblenz, Germany, June 3–7 2013.

Climate – Knowledge Uncertainty

• Detectability of change• Characteristics of change: intensity, speed,

signal-to-noise ratio (conditional upon time)• Attributability of change (various drivers)• Intensity and effectivity of claimsmaking by

economic stakeholders and green ideology (post-normal science)

• Presence and emergence of other drivers

Certainties• Risks exist and may change, some will.• Climate (statistics of weather) is changing – as well as

associated probabilities of hazardous situations – due to elevated GHG levels.

• A new “stationary” state will hardly be reached; statistics are getting instationary.

• The level of adaptation to change depends on the success of limiting the change (Klimaschutz)

• Scientific skeptic is needed.• Overselling of claims-making is counterproductive on the

long run.

Certainties- the time dimension

• Learning in time – in 10 years we know more than today, in 20 years more than in 10 years.

• Societal values change in time• Technology changes – new, cheaper and more

flexible answers to challenges will be available.• Drivers of change will become more – some

gradually, some abrupt and surprising.• Success of limiting anthropogenic climate change

gradually becomes a “known”

Consequences for today

• Maintenance and regular modernization should consider perspective of future change and flexibility in responding to such change.

• Decision needed as to when new adaptation measures should be implemented.

• Consideration of change of all drivers.• Societal debate needed about options and timing.• Check of societal claims-making reflecting special

interests.

Research Needs

• Development of new or improved technology options for dealing with present and changing risk.

• Monitoring of environmental state, which allows detecting changing risks and attributing to causes.

Coastal Defense: Detection, Attribution

37 year trencs (2 x nodal tide) of regional sea level in the German Bight

black, green: two reconstruction methodsrot – Cuxhaven, Albrecht et al. 2011

Difference of maximum heights in Hamburg and Cuxhaven

Storm surges in Hamburg elevated because of modifying the river Elbe – both coastal defense and shipping channel deepening

Green ideology misleading the public

Claimed flooding associated with a sea level rise of 1 (?) m.

Area protected by contemporary coastal defense against “normal” high tide sea level.

Coastal DefenseAnalysis for Coastal Defense in Schleswig Holstein (Landtag, Kiel), in 2009

Fortification of dikes in Schleswig-Holstein

Significant 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

Niemeyer & Kaiser 2008, NLWKN

Currently overtopping tolerances: 3% of all – Lower Saxony 2 l/(m∙s) – Masterplan

Schleswig-Holstein 0,1-1,0 l/(m∙s) – The Netherlands

Results of overtopping test in Delfzijl/NL No damage up to 50 l / (m s)∙ No severe damage at 50 l (m ∙ s) after artificial damage still functioning

Technology: Dyke overtopping tolerance

Overall conclusion: Time!When adapting to and talking about climate change three major, often overseen issues are

- The issue is not new risk, but changing risk- Time is a key dimension – change occurs in time;

development is instationary.- Knowledge, drivers and options for adaptation

change in time.