Hans von Storch Institute of Coastal Research, Helmholtz Zentrum Geesthacht and KlimaCampus Hamburg Germany. Research on Climate Impacts in Hamburg and Schleswig Holstein.
Hans von Storch
Institute of Coastal Research, Helmholtz ZentrumGeesthacht
and KlimaCampus Hamburg
Many thanks to Jacobus Hofstede, Heinke Schlünzen, Benno Hain, Insa Meinke, Jörg Knieling, Grit Martinez and Olaf Müller for helpful comments.
Technology oriented: offshore operations (marine/coastal) transport
National climate service: CSC, DWD
Regional climate service: [email protected]
BSH, DWD (SWA), BAW
Max-Planck Society: MPI of Meteorology
Helmholtz Association: HZ Geesthacht, Kiel; Bremerh.
Hamburg (UHH, HCU, TUHH) CAU Kiel
In the last decade, CO2 emissions are not only continuing to increase, but accelerating.
Also the growth of CO2 concentations in the atmosphere is acceleratimg.
A tendency towards limiting the rate of increase does not exist at this time.
Chances for reaching the 2o-goal are small; a goal below 2o is unrealistic.
2o goal and adaptation
A robust expectation
Global air temperature will increase in 2100 at least by 2oC.
The effects of man-made climate change will become more distinct and more consequential in the next decades.
The need for adapting to the non-avoidable change will grow – the more the less effective a global climate protection policy will become.
GISS estimate, 2011
Future anthropogenic climate change, or Global Warming, is described by scenarios.
Alternative scenarios about economic and social developments in the coming 100 years are made; from these assumptions emissions of greenhouse gases are estimated; the climatic effect of these are assessed by running climate models.
The resulting knowledge are not predictions, but projections conditional upon certain emission scenarios.
If, however, all scenarios point to the same development, then they collectively become predictions – namely that temperatures as well as sea level will rise.
IPCC SRES scenarios
Are present changes indicators of future changes?
To do so, one may compare the change in the past, say, 30 years with the change envisaged by the scenario calculations.
This has not often been done systematically - one case being temperature and precipitation in the Baltic Sea catchment.
It is found that the ongoing temperature change is broadly consistent with the future expectation, but that the consistency is limited for precipitation.
Bhend, pers. comm, 2011
Christmas flood 1717
For the low-lying Northern Germany, storm surges represent the greatest geophysical hazard
In the past, very strong storm surges have breached coastal defense, with many dead and much damage.
However, after the 1962 flood, the hazard seems mostly checked by an efficient coastal defense, even if a remaining (albeit small) risk prevails
Which effect will climate change have on this hazard?
Hamburg flood, 1962
Graphik: Michael Schrenk
Storm surges are a threat for the low-lying areas along the (not only) German coasts (both North Sea and Baltic Sea)
Climate Change as well as the improvement of waterways and of coastal defense are associated with changes of the storm surge hazard.
The North Sea is one of the best observed marginal seas. Here, an accelerated increase in sea level has not (yet?) been identified in the observed data; also storm activity remains mostly stationary, albeit undulated by decadal variation.
For the future, changes are to be expected. Chiefly for mean sea level (until 2100: 20-80 cm), to a lesser extent for storms (until 2100: up to 30 cm).
A need for further improving coastal defense will emerge after 2030; until then, planning and discussion about options as well as maintaining the present levels of protection is needed. Building structures, which allow additional fortification at a later time is prudently done already now.
Differences of storm surge heights in Cuxhaven (mout of Elbe) and Hamburg (St. Pauli) since 1900
Options for adaptation
Graphik: Michael Schrenk
Pasche et al., 2008
How strongly do you employ the following sources of information, for deciding about issues related to climate adaptation?
Survey among regional administrators in German Baltic Sea coastal regions.
Bray, 2011, pers. comm.
The medial-cultural constructed mental model of climate change
Mankind is changing climate, mostly by excessive use of fossil energy, but also locally by deforestation.
The weather is less reliable than previously, the seasons are more erratic, storms more violent. Weather extremes have become catastrophic to an extent never seen before.
Almost all contemporary weather extremes are related to man-made global warming.
The cause of all this is „human greed“ and “stupidity“, the mechanism is „revenge of nature“. Damaging extremes are a warning for humankind.
Regional Climate Service