Transcript North Sea Storm Surges and climate change

SWIM 23rd SaltWater Intrusion Meeting June 16-20 2014, Husum
Science, policy, decision making and public participation the challenge of climate change at the coast
Hans von Storch and Norddeutsches Klimabüro
June 16, 2014
…from a global to a regional perspective:
The Northern German Climate Office
Aim: to construct methods making decision relevant climate knowledge for in Northern Germany
available for stakeholders in climate sensitive fields. This requires the establishment of a dialogue
between research and stakeholders.
The tools of North German Climate Office comprise various tailored information products on
climate change in Northern Germany. These products serve as scientific basis for adaptation
strategies for example in coastal protection, agriculture, fishing and tourism.
Some tools are developed together with the German Weather Service.
Dialogue-based: The experiences achieved from an intensive long-term stakeholder dialogue help
to prepare research results in an understandable and tailored manner.
Research based: As part of the Institute of Coastal Research at the Helmholtz-Zentrum Geesthacht
and of the KlimaCampus Hamburg the information is based on the current state of research.
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Outline
Weather, Climate, Climate Change
Climate change during the past 100 years
- Global climate change
- Regional climate change in Northern Germany
- North Sea storm surges in recent climate change
Possible future climate change until 2100
Regional Climate Servicing
- Effects of climate change at the lower Elbe river and on groundwater quality in the Elbe marshes
- North Sea storm surges and coastal protection in future climate change
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What is weather?
 Weather is the timed sequence of atmospheric states (events) – such as three days of sunshine, or a
storm, on a specific date.
 Weather is predicted by determining the present state and then deriving how this state may develop in
the coming days.
 Weather forecasting beyond 10 days, or so, is in principle impossible.
 The future weather may be seen as the outcome of a random events – for forecasts times of more than
10, or so, days – like rolling a dice.
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Definition of climate and climate change
 Climate is the statistics of weather, such as the frequency of three days of sunshine in December in
Husum, or the probability of a storm.
 Climate is quantified by determining how often which weather events take place, and then deriving
characteristic numbers, such as the maximum wind, the mean temperature, correlations etc.
 Predicting weather beyond 10 days is like forecasting the next outcome of rolling a dice, predicting
climate is like describing the frequencies of the different outcomes of rolling a dice.
 Problem: In general, we can not really predict the future influence conditions, so that we can say only
what the climatic consequence may be if the influence conditions are changing in some way. We can
construct “scenarios” or “projections” but cannot “predict” climate.
 But we can estimate “What happened, if…”. These estimates take the form of condition predictions, and
are named “scenarios” or “projections”
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Recent global climate change –
Key findings of IPCC 2013
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Temperature anomaly (°C) relative to 1961–1990
Recent global climate change – Temperature
© IPCC 2013
 Earth surface temperature has been successively warmer in the last three
decades than in any previous decade since 1850.
 1983–2012 was the warmest 30-year period of the last 150 years.
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Recent global climate change –
human influence
The recent global climate change can
not be explained without human
influence regarding:
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Temperature (land and ocean surface)
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Northern hemisphere sea ice extent
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Ocean Heat Content (OHC)
© IPCC 2013
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Recent regional climate change
in Northern Germany
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Northern German Climate Monitor
As part of the implementation of the German adaptation strategy a regional climate
monitoring system is needed. Therefore, the Northern German Climate Office and the
Regional Climate Office Hamburg of the German Weather Service (DWD) have
developed the Northern German Climate Monitor :
www.norddeutscher-klimamonitor.de
Previous development of the average annual temperature in northern Germany
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Product on recent regional climate change:
Northern German Climate Monitor
The Northern German Climate Monitor provides
information on climate in Northern Germany in the last
60 years (1951-2010).
recent climate
 Recent climate, recent climate change and consistency
with scenarios of change.
 Data of 22 stations of the DWD (German Weather
Service) monitoring network have been included.
 In addition, the Northern German Climate Monitor is
based on various comprehensive model datasets
including the coastDat dataset of the HZG.
 The Northern German Climate Monitor provides
information on parameters like wind, humidity, cloudiness
and sunshine duration additional to the usual parameters
such as air temperature and precipitation. The user can
select different regions, seasons and time periods.
www.norddeutscher-klimamonitor.de
recent climate change
Previous development of the average annual temperature in northern Germany
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North German temperature: annual mean
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Recent temperature increase
All regional scenarios points towards a
warming
The recent warming is within the range of
expected changes caused by elevated
greenhouse gas concentrations
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North German intensity of storms in winter (DJF)
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Very slight recent increase of
storm intensity
Regional scenarios agree on a
weak intensification until the end
of the century
Models anticipate an
intensification larger than the
linear extrapolation of present
intensification
Model changes inconsistent with
observed changes (maybe
because of reduced regional
aerosol load)
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North German precip amounts in summer (JJA)
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Increase in summer precipitation
amount
Regional scenarios agree on
reduction until the end of the
century
Models anticipate an reduction,
while the present trend is towards
more summer rain
Model changes inconsistent with
observed changes (maybe
because of reduced regional
aerosol load)
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North German precip amounts in winter (DJF)
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Increase in winter precipitation
amount
Regional scenarios agree on
increase until the end of the
century
Model changes of winter
precipitation consistent with
observed changes, thus observed
changes could be explained by
increased GHG concentrations
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North German strong rain events in summer (JJA)
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Number of days with more than
20 mm precipitation in summer
Recent increase in number of
summer heavy rain days
Regional scenarios show small
changes, both negative and
positive
Model changes inconsistent with
observed changes (maybe
because of reduced regional
aerosol load)
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North sea storm surges and recent
climate change
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North Sea Storm Surges and climate change:
Global sea level rise
 Global average sea level has increased about 20 cm during the last century.
© IPCC 2013
 The sea level rise varies regionally.
Source: Geographic distribution of long-term linear trends in mean
sea level (mm yr–1) for 1955 to 2003 based on the past sea level
reconstruction with tide gauges and altimetry data
(updated from Church et al., 2004)
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North Sea Storm Surges and climate change:
Sea level rise in the North Sea
 In the North Sea, sea level has risen about 20 cm during the last century.
Regional sea level (Deviation from the reference period)
 So far, in the North Sea the increase shows no extraordinary acceleration.
Source: Albrecht et al. 2010
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North sea storm surges and climate change:
Intensity of North Sea storms
 Looking at the last 125 years North Sea storms have not yet become more intense.
wind speed
annual means
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Source: Rosenhagen 2008
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North sea storm surges and climate change:
Effect of wind on water levels
 Today, wind storms increase water levels no more than in the past…
…but sea level:
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North Sea Storm Surges:
Storm surge heights in Hamburg
 Storm surges in Hamburg have increased in height and frequency since 1963
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North Sea Storm Surges:
Storm surge heights in Hamburg
 Water engineering measures have increased storm surges in Hamburg
Differences of the storm surge heights Hamburg - Cuxhaven
Source: Storch et al. 2008
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Possible future climate change
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Global future climate change – Temperature
© IPCC 2013
 Global surface temperature change may exceed 1.5°C relative to 1850 to 1900 for all RCP scenarios
except RCP2.6.
 It is likely to exceed 2°C for RCP6.0 and RCP8.5, and more likely than not to exceed 2°C for RCP4.5.
 Under all RCP scenarios except RCP2.6. warming will continue beyond 2100.
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Global future climate change –
Mean sea level rise
 Due to increased ocean warming
and increased loss of mass from
glaciers and ice sheets global mean
sea level will continue to rise during
the 21st century.
 Under all RCP scenarios sea level
rise accelerates compared to 1971 to
2010.
 The range of expected sea level rise
until the end of the century is
between 20 and 80 cm.
 The increase of sea level will
continue beyond 2100.
© IPCC 2013
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Product on possible regional future climate change:
Northern German Climate Atlas
As part of the German Adaptation Strategy (DAS) from 2008
the Northern German Climate Atlas was designed.
 This interactive internet tool provides users with
understandable maps and short explanations on ranges of
expected future climate change in Northern Germany.
 Additional to the usual parameters such as air temperature and
precipitation the Northern German Climate Atlas
also provides information on parameters like wind, humidity,
cloudiness and sunshine duration.
www.norddeutscher-klimaatlas.de
in english: www.coastalatlas.org
 Users can select different regions, seasons and time periods.
How may temperature change in
Northern Germany in future?
Is winter rain fall increasing in my
region?
Do we have to expect more storms in
winter?
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Northern German Climate Atlas
Future climate change in Northern Germany
Annual mean temperature
Possible mean change of the annual mean temperature until the end of the 21st century (2071-2100) compared to
today (1961-1990): Increase
In Northern Germany all implemented (12) regional climate scenarios agree in 100 % of the area (orange).
They show a higher mean temperature. This increase may lie between +2.0 and +4.7°C.
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Northern German Climate Atlas
Future climate change in Northern Germany
Precipitation: Summer
Possible change of precipitation in summer until the end of the 21st century (2071-2100) compared to today (19611990): Decrease
In Northern Germany all implemented (12) regional climate scenarios agree in 86 % of the region (orange).
They show less precipitation in summer. This decrease may lie between -8 and -40%.
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Northern German Climate Atlas
Future climate change in Northern Germany
Precipitation: Winter
Possible change of precipitation in winter until the end of the 21st century (2071-2100) compared to today (19611990): Increase
In Northern Germany all available regional climate scenarios agree in 100 % of the region (blue).
They show more precipitation in winter. This increase may lie between +11 and +41%.
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Regional climate servicing:
Making knowledge useful
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Product on the need for coastal protection:
www.kuestenschutzbedarf.de
Protected area today – at normal flood (yellow) and at storm surge (light green)  ~ 11.000 km
Gelb: normales Tidenhochwasser,
Hellgrün: 16. Feb. 1962
Dunkelgrün: 16. Feb 1962 + 1,10 m
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
How strongly do you employ the
following sources of information,
for deciding about issues related to
climate adaptation?
Regional administrators in German
Baltic Sea coastal regions.
Bray, 2011, pers. comm.
Regional Climate service comprises …
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 and dissensus on relevant
issues (climate consensus reports).
3. Description of recent and present changes.
- Projection of possible future changes, which are
dynamically consistent and possible („scenarios“)
Product: Assessment report of climate change in the
metropolitan region of Hamburg
The “Climate report for the metropolitan region of Hamburg” is an IPCClike assessment of the scientific knowledge on regional climate, climate
change and climate impact. The region covers the larger Hamburg area
and the west coast of Schleswig-Holstein. The assessment was prepared
by the center of excellence clisap at Hamburg University, and was
coordinated by the Northern German Climate Office.
 Scientists of different scientific disciplines made an inventory of scientific
knowledge and discussed contested results.
 Many applied issues have not been sufficiently studied for the regional
considered.
www.klimabericht-hamburg.de
 The findings were documented in an assessment report, which has been
peer-reviewed and published as a book “Klimabericht für die Metropolregion
Hamburg” (Climate assessment for the metropolitan region of Hamburg).
 For stakeholders working in climate sensitive fields like coastal protection,
agriculture or tourism this assessment report represents a legitimate
scientific basis on which adaptation strategies on climate change in the
metropolitan region of Hamburg can be developed.
 This assessment report was published in 2010.
 New results have likely generated by now, in particular within the framework
of KLIMAZUG-NORD.
Main findings of the book summarized
in an understandable booklet
Effects of climate change on the lower Elbe river
and the groundwater quality in the Elbe marshes
 Upstream relocation of the brackish water zone / turbidity zone due to
1) sea level rise,
2) a seasonal reduction of inflow from the upstream part of the Elbe river
3) water engineering measures.
 Increased salinity …
- leads to limited access to fresh water for example for frost protection
irrigation in the orchards of Altes Land – the largest contiguous
fruit-growing area in Germany - or as process water in industry.
- upstream has an effect on upstream fresh water ecosystems and
species (for example on spawning areas of protected fish species).
- may also lead to groundwater quality changes due to increased
penetration of brackish water into the aquifer. The effect of saltwater
intrusion will increase downriver.
Status 2009
 In more wet winters with higher discharges the problem of an upstream
displacement of the turbidity zone upstream may be less significant. At
the same time, an increased inflow of pollutants from the Elbe catchment
area into the estuary may take place.
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Products of the North German Climate Office:
Brochure „North Sea Storm Surges and Climate Change“
On the occasion of a hearing in the parliament of SchleswigHolstein in 2009, the North German Climate Office summarized the
results on the impact of climate change on storm surges in the North
Sea and placed the findings into the regional context.
 Until now anthropogenic climate change has only little effect on North
Sea storm surges. Until 2030 the current coastal protection is
considered to be almost as effective as today.
 However, until 2100 there might be a need for additional coastal
protection strategies since storm surge heights may increase by about
30 to 110 centimetres compared to today (1961-1990).
 The impact of coastal climate change on tides, sedimentation and the
interaction of coastal engineering measures with water levels in the
German Bight is currently subject of research.
The brochure can be ordered at the
North German Climate Office:
www.norddeutsches-klimabüro.de
A format
to deal with changing coastal flooding risk
1) Recognize that climate is changing, mostly caused by ongoing emissions of
greenhouse gases.
2) Sea level is and will continue to rise in the future. A new stationary state is
not in sight.
3) The strength of the future rise is only inaccurately known at this time. Many
more years are needed to reach accuracy.
4) Storm surges will become higher in future; this is mostly due to sea level rise,
and only, if any, due to stronger storms
5) Any decision in the foreseeable future will have to deal with this incomplete
knowledge
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A format to deal with the changing
coastal flooding risk
1) Recognize that climate is changing, mostly caused by ongoing emissions of greenhouse gases.
2) Sea level is and will continue to rise in the future. A new stationary state is not in sight.
3) The strength of the future rise is only inaccurately known at this time. Many more years are
needed to reach accuracy.
4) Storm surges will become higher in future; this is mostly due to sea level rise, and only, if any,
due to stronger storms
5) Any decision in the foreseeable future will have to deal with this incomplete knowledge
6) Adopt two different time horizons, say 2030 and 2080.
7) The increase in risk will be small until 2030.
8) The increase in risk may become large, even very large in 2080.
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A format to deal with the changing
coastal flooding risk
1) Recognize that climate is changing, mostly caused by ongoing emissions of greenhouse gases.
2) Sea level is and will continue to rise in the future. A new stationary state is not in sight.
3) The strength of the future rise is only inaccurately known at this time. Many more years are
needed to reach accuracy.
4) Storm surges will become higher in future; this is mostly due to sea level rise, and only, if any,
due to stronger storms
5) Any decision in the foreseeable future will have to deal with this incomplete knowledge
6) Adopt two different time horizons, say 2030 and 2080.
7) The increase in risk will be small until 2030.
8) The increase in risk may become large, even very large in 2080.
9) First decisions are needed now.
10) New measures do not need to be built NOW, but maybe later.
11) The ongoing maintenance and routine modernization should be done such
that future fortifications are possible.
12) The range of options for future strategies should be enlarged.
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A format to deal with the changing
coastal flooding risk
9) First decisions are needed now.
10) New measures do not need to be built NOW, but maybe later.
11) The ongoing maintenance and routine modernization should be done such
that future fortifications are possible.
12) The range of options for future strategies should be enlarged.
13) The development of sea level and storminess needs to be monitored, so
that different scenarios of possible development can be assessed as more or
less realistic
14) Present coastal defense should be designed so that it can be heightened at
a later time. (e.g., 50 cm Klimazuschlag)
15) Discussions with stakeholders (population) different response strategies will
be helpful for planning and future decision making
16) New technology for, e.g., dikes (e.g., overtopping tolerance) should be
developed
17) Possible measures may be combined with other political goals.
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Thanks for your attention!
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