1. Scientific tools for public-science interaction
Hans von Storch
Institut für Küstenforschung, GKSS Forschungszentrum Geesthacht
clisap-Exzellenzzentrum, Klimacampus, Universität Hamburg
Etwas gekürzt im vergleich zu Bologna, Okt 2008

2. A few facts - 1
Climate change is a „constructed“ issue. People do not really experience „climate change“.
One construction is scientific, i.e. an „objective“ analysis of observations and interpretation by theories.
The other construction is cultural, in particular maintained and transformed by the public media.

3. 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
Lund and Stockholm
Stürme

4. The increase in damages related to extreme weather conditions is massive – but is it because the weather is getting worse?
Losses from Atlantic Hurricanes
Hardly
“Great Miami”, 1926, Florida, Alamaba – damages of 2005 usage - in 2005 money: 139 b$
Katrina, 2005: 81 b$
Pielke, Jr., R.A., Gratz, J., Landsea, C.W., Collins, D., Saunders, M., and Musulin, R., Normalized Hurricane Damages in the United States: Natural Hazards Review

5. A few facts - 2
Climate is changing on time scales of decades and centuries.
Presently climate is changing mainly because of elevated concentrations of greenhouse gases in the atmosphere.
This change is best detectable in temperature and related quantities, and will become visible during this century also in other variables, in particular related to the water cycle.
Climate change has an impact on social life and ecosystem functioning.

6. A framework to think about response strategies
(Hasselmann, 1990)

7. Possible Reponses to Anthropogenic Climate Change
In the interacting environment-and-society system, we have two classes of options for response:
trying to avoid man-made changes („mitigation“) – this has different dimensions, namely avoiding elevated levels of GHG concentrations by reduced emissions; by intensified sinks; by geo-engineering the global albedo, or regional and local conditions.
adapting to man-made changes („adaptations“) of climate.
In principle, limiting the cause of anthropogenic climate change (i.e., reduction of emissions) is preferable over adaptation, but complete mitigation seems impossible so that the best strategy is to mitigate as much as affordable and to minimize negative consequences by adaptation.

8. Is scientific knowledge driving the policy process?

9. 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.
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.
The social process „science“ is influenced by these other knowledge forms.
Science can not be objective but should nevertheless strive to be so.

10. Scientific needs
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.
Two-way interaction of stakeholders and climate knowledge brokers in „Klimabureaus“.
Analysis of consensus on relevant issues (climate consensus reports).
Description of of recent and present changes.
Projection of possible future changes, which are dynamically consistent and possible („scenarios“).

11. Northgerman Climate Bureau

12. Klimabüro für Polargebiete und Meeresspiegelanstieg - Polare Gebiete - Inlandeis - Meeresspiegel
Süddeutsches Klimabüro - Süddeutschland - Überschwemmungen - Starkniederschläge - Gewitter
Mitteldeutsches Klimabüro - Mitteldeutschland - Landnutzung - Wasserkreislauf - Biota

13. Requests for talks Total number of talks since 2006: 84
Average number of presentations per months.
Jan March 2007: 1,0
March 2007-Feb. 2008: 4,2
March 2008-Oct. 2008: 2,4
Regional level: 58%
National level: 30%
International level: 12%

14. Frequently asked questions
Climate variations are normal, why is the recent warming not normal?
How can we talk about future climate if we are not able to forecast the weather of tomorrow?
When do we expect the next ice age?
Will the gulf stream slow down?
Is there already an accelerated sea level rise?
How much will sea level rise in future?
Are our dikes high enough?
Will Hamburg be flooded?
Are there any advantages in climate change?
What can we do?

15. Expected changes in temperature, precipitation and strong winds
Scenarios A2, B2, different models

16. Expected changes in temperature, precipitation and strong winds
Scenarios A2, B2, different models

17. Changing storm surge heights in Cuxhaven und Hamburg
Without subsidence or coastal engineering modifications of the river Elbe.

18. A mitigation option: „regional geo-engineering“ to dampen tidal dynamics and cut storm surge peaks

19. A mitigation option: reversing (part of) the urban warming by „regional geo-engineering“
Gill et al.,2007

20. The Climate Change Assessment: Report for the Baltic Sea catchment - BACC
An effort to establish which scientifically legitimized knowledge about anthropogenic climate change is available for the Baltic Sea catchment.
Approximately 80 scientist from 10 countries have documented and assessed the published knowledge.
The assessment has been accepted by the inter- governmental HELCOM commission as a basis for its future deliberations.
In 2012 a second assessment report (BACC II) will be published.
45 min‘s

21. The BACC Project integrates available scientifically documented knowledge of historical, current and expected future climate change.
The unique feature of BACC is the combination of evidence on climate change and related impacts on marine, freshwater and terrestrial ecosystems in the Baltic Sea basin (catchment and water body).
It is the first systematic scientific effort for assessing climate change in the Baltic Sea region.
The results have not been influenced by either political or special interests.

22. Past and current climate change
Air temperatures in the Baltic Sea basin already have risen over the past century (time series since 1871), increasing by approximately 1ºC in the northern areas of the Baltic Sea basin and by around 0.7ºC in the southern areas.
Most pronounced warming in spring.
Related observed changes in winter runoff, ice duration and snow.
More precipitation in the 2nd half of the 20th century with major regional variations.
No systematic change in windiness found.
No clear long-term trends in Baltic Sea salinity.

23. Air-temperature
Note – time series has been „cleaned“; instrumental inhomogeneities and local effects (such as growing cities) have been taken out.

24. Ongoing changes in regional ecosystems
Associated changes in terrestrial ecosystems include - earlier spring phenological phase, - northward species shift, and - increased growth and vigour of vegetation.
Robust assessments of changes in marine ecosystems related to climate change are hardly possible at this time.
Further research is needed to discriminate between climate change and other anthropogenic drivers such as over-fishing, euthrophication, air pollution and land use changes.

25. Terrestrial ecosystems
Mean rate of change (days/year) of date of leaf unfolding in birch,

26. Scenarios of future climate …
… constructed by feeding assumed emissions of greenhouse gases and aerosols into quasi-realistic models of the climate system.
Future emissions can not be predicted; only plausible and consistent visions of the future (i.e., scenarios; projections) are possible.
Scenarios provide a frame for decision makers to explore the range of policy options to deal with the reality of anthropogenic climate change.
Scenarios are no predictions.

27. Scenarios of future regional climate change
Increasing temperatures very likely during the entire 21st century: air temperatures could rise by 4º–6ºC in northern areas such as Sweden, Finland, and western Russia and by 3º–5ºC in southern areas such as Poland and northern Germany until the end of this century.
Precipitation is expected to change as well, with possible increases of 20–75% during the winter season over the entire basin. During summer, the northern areas would experience a slight increase (-5% to +35%), while a strong decrease of up to 45% is expected for the southern areas.
No clear projection for wind speed and storms.

28. Mean number of ice days in a present day simulation (top) and two scenarios of 2070-2100 (bottom)

29. Projections of future climate impacts on marine ecosystems
No detailed, comprehensive analysis available –projections are more ad-hoc and uncertain.
Effect of other changing influences hardly predictable.
Possible Baltic Sea salinity decrease would have major effect on marine fauna.
Expected changes in precipitation and river runoff may have additional detrimental effects on the problem of eutrophication.

30. Climate assessment for the metropolitan region of Hamburg
In a climate assessment report about the scientifically documented knowledge of climate change in the region of Hamburg will be prepared. This is an activity of the Climate Center of Excellence CLISAP at the University of Hamburg, jointly operated with GKSS and MPI.
The effort is supported by the Senate of Hamburg and by the Environmental Ministry of Schleswig Holstein.

31. Regional and local conditions – in the recent past and next century?
Simulation with barotropic model of Noth Sea
Globale development (NCEP)
Dynamical Downscaling REMO or CLM
Pegel St. Pauli
Cooperation with a variety of governmental agencies and with a number of private companies
Empirical Downscaling

32. Piecewise linear trends
(Weisse et al. 2005)

33. Scenarios for 2085 A2 - CTL: changes in 99 %iles of wind speed ;
6 hourly, DJF; west wind sector selected
HIRHAM
RCAO
Scenarios for 2085
Woth, personal communication

34. How did wind-storm impact on storm surges and ocean waves develop in the past decades, and what may happen in the expected course of anthropogenic climate change?
In the recent decades, , an increase of marine storminess was recorded – simultaneous with an intensification of the NAO (North Atlantic Oscillation);
Since 1995 this trend has reversed in most marine areas.
Scenario simulations with regional models – and subsequent simulations with storm surge and ocean wave models – point to an increase of marine storminess in the Southern North Sea in the course of emerging anthropogenic climate change. Expected increases of strong winds are of the order of 10% for the end of the 21st century.
Storm surge heights are expected to rise along the German North Sea coast by about 70 cm (with less than half due to changing storminess) at the end of the 21st century. For high waves, the increase may be of the order of 30 cm’s.

35. www.coastdat.de The CoastDat data set:
Long (50 years) and high-resolution reconstructions of recent offshore and coastal conditions mainly in terms of wind, storms, waves, surges and currents and other variables in N Europe
Scenarios (100 years) of possible consistent futures of coastal and offshore conditions
extension – ecological variables, Baltic Sea, E Asia, Laptev Sea
Clients:
Governmental: various coastal agencies dealing with coastal defense and coastal traffic
Companies: assessments of risks (ship and offshore building and operations) and opportunities (wind energy)
General public / media: explanations of causes of change; perspectives and options of change
GKSS in Geesthacht

36. Final comment: science, policy and responsibility
(Geophysical, ecological) Science should not formulate policy, but prepare the factual basis for decision makers, who consider apart of geophysical and ecological facts also other, in particular normative arguments.
Climate change is real and mostly caused by human emissions. Society wants to avoid such a change; thus, reductions of emissions are needed („mitigation“).
Any conceivable mitigation policy will not lead to an ending or even reversal of global warming; thus the need for adaptation emerges.
Mitigation should be the main issue for policy at national and European level; adaptation should be chiefly considered on the regional and local level.