Flooding extremes – human sins and Global Warming Hans von Storch – climate scientist Institute for Coastal Research, GKSS, Germany (lead author IPCC TAR) Science and Politics of the Riverside: Steps Towards an Integrated Perspective on Highwaterlevels in the Netherlands and Germany Interdisciplinary Workshop on 11th of June 2003, Nijmegen

The 2002 Flooding in the German media – man made, self inflicted, just the beginning of ongoing catatrophe

Sächsische Zeitung 17.08.02 Zitat Nun ist die Flut also da, vor der eigenen Haustür. Das berührt, weil diese ‚Sintflut‘ so viel unerbittlicher als ferne Katastrophen die Frage nach dem Warum stellt, nach begangenen Sünden, nach deren Verursachern. Wir können heute auch ohne wissen-schaftlichen Beleg davon ausgehen: An der Erderwärmung sind nicht allein periodische kosmische Veränderungen schuld, (...) sie ist ebenso eine Folge unserer Lebensweise. Werner Krauß, 2003

HA 15.08.02 Trifft uns bald härter Werner Krauß, 2003

USA Index of extreme weather on US TV News Sheldon Ungar, 2003 MOST IMPORTANT PROBLEM FACING THE COUNTRY Economy, jobs 40% War, terrorism 15% Education 4% Family values 3% Health care 3% Poverty 3% CBS POLL, May 2003 Index of extreme weather on US TV News USA CLIMATE RESEARCH Clim Res Vol. 23: 263–274, 2003 Global warming versus ozone depletion: failure and success in North America Sheldon Ungar Inset: Environmental Defense Survey, 2000 Environmental Defense Survey, 2000 Sheldon Ungar, 2003 Annual Coverage of GW on US TV News

Scientific foundations: Anthropogenic climate change, the IPCC assessment

IPCC, 2001 Vergleich des Temperaturanstieges seit 1850 in Klima-modellsimulationen und in der Beobachtung

“SRES” Scenarios SRES = IPCC Special Report on Emissions Scenarios Institut für Küstenforschung I f K A world of rapid economic growth and rapid introduction of new and more efficient technology. A very heterogeneous world with an emphasis on family values and local traditions. A world of “dematerialization” and introduction of clean technologies. A world with an emphasis on local solutions to economic and environmental sustainability. “ business as usual ” scenario (1992). A1 A2 B1 B2 IS92a IPCC, 2001

Die Temperaturänderung für alle SRES Szenarien IPCC, 2001

Wahrscheinlichkeitsstufe beobachteter Veränderungen (zweite Hälfte des 20. Jahrhunderts) Wahrscheinlichkeitsstufe prognostizierter Veränderungen (während des 21. Jahrhunderts) Wahrscheinlich Höhere Maximum-Temperaturen und mehr heiße Tage in nahezu allen Landgebieten Sehr wahrscheinlich Höhere Minimum-Temperaturen, weniger kalte Tage und Frosttage in nahezu allen Landgebieten Reduzierter Unterschied zwischen Tagesmaxima und -minima in den meisten Landgebieten   Wahrscheinlich, in vielen Gebieten Höherer Hitze-Index in Landgebieten Sehr wahrscheinlich, in den meisten Gebieten Wahrscheinlich, in vielen Land- gebieten der mittleren und höheren Breiten d.Nordhalbkugel Häufigere Starkregen Wahrscheinlich, in wenigen Gebieten Zunahme kontinentaler Trockenheit und Dürrerisiken im Sommer Wahrscheinlich, in den meisten kontinentalen Gebieten der mittleren Breiten (Fehlen konsistenter Prognosen über andere Gebiete) In den wenigen vorliegenden Analysen nicht beobachtet Zunahme der Windgeschwindig- keitsspitzen in Hurrikanen Wahrscheinlich, in einigen Gebieten Zu wenige Daten für eine Beurteilung Zunahme der mittleren und extremen Niederschlagsstärken bei Hurrikanen  

Scenario for changing precipitation in summer at the end of the 2st century Christensen and Christensen, 2003, nature Change (%) in mean summer precipitation total in 99% quantile 5-daily precipitation amounts (rare events)

Discrimination between „rare, but normal“ and „beyond the range of normal events“ – detection and attribution

Institut für Küstenforschung I f K

Ausgewählte Hochwasserstände am Pegel Dresden Grünewald, 2003 Quelle: LfUG, 2002 19

Niederschlags-geschehen „Dreißigjährige Hochwasser- und Schadensbilanz Osterzgebirge“ Datum Niederschlags-geschehen materielle Schäden Tote 29./30. Juli 1897 140 mm in 24 h in Kammlagen des Erzgebirges zerstörte Eisenbahnstrecken und Ortschaften in den Tälern der Gottleuba, Müglitz und Roten Weißeritz, aber auch im Muldetal und in der Chemnitz mind. 8 08./09. Juli 1927 in wenigen Stunden 200 mm; im Zentrum von 44 km² in 25 min rund 100 mm 110 Brücken zerstört, 160 Brücken beschädigt, 188 Gebäude zerstört 70 Mio. Reichsmark Schaden 152 22./23. Juli 1957 Starkniederschläge mit Zentrum Obere Gottleuba, > 150 mm in 24 h direkte Sachschäden: 67 Mio. Mark Gesamtschäden: 100 Mio. Mark Grünewald, 2003 2. Alle dreißig Jahre im (sächsischen) Osterzgebirge eine „hochwasserbedingte Katastrophe“ ? 20

Bergießhübel 1927 – Die Flut war so hoch wie der als Ramme wirkende Baumstamm Grünewald, 2003 2. Alle dreißig Jahre im (sächsischen) Osterzgebirge eine „hochwasserbedingte Katastrophe“ ? 21

Häufigkeit von Vb Wetterlagen mit schweren Niederschlägen, 1897-2000 Brázdil, 2000

Extremereignisse treten nicht isoliert auf, sondern in Schüben. Extreme Überschwemmungen in den alpinen Einzugsgebieten der Rhone, der Reuss/Linth, des Ticino und des Rheins sowie Hochstände des Lago Maggiore in den vergangenen fünfhundert Jahren. Aus Pfister, 1999 Extremereignisse treten nicht isoliert auf, sondern in Schüben.

Scenario for changing precipitation in summer at the end of the 2st century Christensen and Christensen, 2003, nature According to the scenario, extreme events may be increased by 40% at the end of the 21 century – the expected effect in 2010 at this time would be 1/10 or less, i.e. we may expect an increase of the extreme event by at most 4% at this time due to the emerging anthropogenic signal. Such a signal is hardly detectable.

Discussion

Anthropogenic climate change is real, and it will accelerate in future. Societies are vulnerable to weather extremes. Contemporary weather extremes (floods, storms) are falsely attributed to climate change. In principle, there are two strategies to respond to anthropogenic climate change: Adaptation – to existing and changing weather patterns. Mitigation – by reducing the emission of radiatively active gases and substances (greenhosue gases and aerosols)

In Germany, and other European countries (e. g In Germany, and other European countries (e.g., DK, S) only the option of „mitigation“ is considered. It is believed that the implementation of the Kyoto-protocol would lead to a significant mitigation. However, Kyoto will at best cause a minor reduction of emissions. A robust expectation is: If no effective emission regulations are implemented, then we will have a quadrupling of greenhouse gas concentrations in the atmosphere at the end of the 21st century, with severe repercussions of the climate system. If a regulation is adopted, then we may end up at the end of the 21st century with a doubling of greenhouse gas concentrations, with less significant changes in the weather patterns. In both cases significant efforts to deal with adaptations are needed. In fact, reducing the vulnerability of societies to weather extremes is a win-win strategy. First, it is reduces contemporary risks, and, if some extremes are really getting worse in future because of elevated greenhouse gas concentration levels, it helps to alleviate some of the dangers of a possible future climate. Thus, a meaningful climate policy should address both aspects, reduction of emissions and reduction of vulnerability. However, the climate policy, engraved in the Framework Convention process, deals only with mitigation.

Why the limitation to mitigation (reduction of emissions)? Cultural reasons – managing the consequences of the evil (anthropogenic climate change) means to support the evil – the morally only acceptable effort is to fight against the evil, i.e., to reduce the emissions. talk about adaptation will cause people to believe that anthropogenic climate change is not that bad, that it can be dealt with. Talk about adaptation is sinful. Political reasons - In developing countries, adaptation measures can hardly be separated from general development. It would need investments in the Third World, not into the own technological development.

Consequences: In Germany, weather extremes are understood as being caused by somebody. Thus, the adequate response is to policy the perpetrator. The best protection against the dangers of flooding is perceived to be a Klimaschutzpolitik. Previously, in 1962 and 1953, the disastrous storm surges in the Netherlands and in Germany were understood as a signal to improve coastal defense; this was done successfully, and the even higher storm surge of 1976 in Hamburg did not cause significant damages. The present perception, and interpretation by politicians and scientists in the media, causes people to no longer follow the 1953/1962 example, but to simply continue as before while requesting financial help for rebuilding and an active Klimaschutzpolitik. Thus, the disregard of measures to reduce the vulnerability, to better adapt to the risks of weather extremes, is not only stupid but has significant adverse effects for people living today.