25 October 2009

The Hohenkammer Consensus on Climate Change and Disaster Losses

In 2006 I co-organized a major international workshop with Peter Höppe, of Munich Re, to focus on the role of climate change, including anthropogenic climate change due to greenhouse gases, in the increasing trend of global disaster losses. This workshop resulted in a set of consensus statements that were subsequently published in Science (PDF) and cited by the IPCC AR4 report. For those interested in what we concluded, in this post I have reproduced the Executive Summary of the meeting report (those wanting more can go here) as well as a list of the Workshop participants.

Comments and questions are welcomed. I believe that the workshop conclusions are as current now as then, and so too does my collaborator Peter Höppe who wrote (along with two other workshop participants) earlier this year that their work "confirm[s] the consensus reached in May 2006 at the international workshop in Hohenkammer attended by leading experts on climate change and natural catastrophe losses."

If you have questions about the Workshop, the consensus statements or research in this area, just ask.

Executive Summary of the Report of the Workshop on “Climate Change and Disaster Losses: Understanding and Attributing Trends and Projections”

25-26 May 2006
Hohenkammer, Germany

On the basis of collaboration between Peter Höppe, Munich Re, and Roger Pielke, Jr., University of Colorado, an international workshop on climate change and disaster loss trends was held in May 2006 in Hohenkammer, Germany with sponsorship from Munich Re, the U.S. National Science Foundation, GKSS Research Center, and the Tyndall Centre. In total 32 experts in the fields of climatology and disaster research from various parts of the world (13 countries) participated.

"White papers" from 25 participants were submitted in advance and formed the basis of the discussions. This Executive Summary reports 20 statements which each represent a consensus among participants on issues of research and policy as related to the workshop’s central organizing questions. A Workshop Summary Report follows which provides greater detail on the statements. The participant white papers, biographies, and workshop agenda are also included.1 The focus of the workshop was on two central questions:

• What factors account for increasing costs of weather related disasters in recent decades?
• What are the implications of these understandings, for both research and policy?

To be clear about terminology, we adopted the IPCC definition of climate change. According to the IPCC (2001) climate change is
“Climate change refers to a statistically significant variation in either the mean state of the climate or in its variability, persisting for an extended period (typically decades or longer). Climate change may be due to natural internal processes or external forcings, or to persistent anthropogenic changes in the composition of the atmosphere or in land use.”2
The IPCC also defines climate variability to be
“Climate variability refers to variations in the mean state and other statistics (such as standard deviations, the occurrence of extremes, etc.) of the climate on all temporal and spatial scales beyond that of individual weather events. Variability may be due to natural internal processes within the climate system (internal variability), or to variations in natural or anthropogenic external forcing (external variability).”3
We use the phrase anthropogenic climate change to refer to human-caused effects on climate.

Consensus (unanimous) statements of the workshop participants:
1. Climate change is real, and has a significant human component related to greenhouse gases.

2. Direct economic losses of global disasters have increased in recent decades with particularly large increases since the 1980s.

3. The increases in disaster losses primarily result from weather related events, in particular storms and floods.

4. Climate change and variability are factors which influence trends in disasters.

5. Although there are peer reviewed papers indicating trends in storms and floods there is still scientific debate over the attribution to anthropogenic climate change or natural climate variability. There is also concern over geophysical data quality.

6. IPCC (2001) did not achieve detection and attribution of trends in extreme events at the global level.

7. High quality long-term disaster loss records exist, some of which are suitable for research purposes, such as to identify the effects of climate and/or climate change on the loss records.

8. Analyses of long-term records of disaster losses indicate that societal change and economic development are the principal factors responsible for the documented increasing losses to date.

9. The vulnerability of communities to natural disasters is determined by their economic development and other social characteristics.

10. There is evidence that changing patterns of extreme events are drivers for recent increases in global losses.

11. Because of issues related to data quality, the stochastic nature of extreme event impacts, length of time series, and various societal factors present in the disaster loss record, it is still not possible to determine the portion of the increase in damages that might be attributed to climate change due to GHG emissions

12. For future decades the IPCC (2001) expects increases in the occurrence and/or intensity of some extreme events as a result of anthropogenic climate change. Such increases will further increase losses in the absence of disaster reduction measures.

13. In the near future the quantitative link (attribution) of trends in storm and flood losses to climate changes related to GHG emissions is unlikely to be answered unequivocally.

Policy implications identified by the workshop participants

14. Adaptation to extreme weather events should play a central role in reducing societal vulnerabilities to climate and climate change.

15. Mitigation of GHG emissions should also play a central role in response to anthropogenic climate change, though it does not have an effect for several decades on the hazard risk.

16. We recommend further research on different combinations of adaptation and mitigation policies.

17. We recommend the creation of an open-source disaster database according to agreed upon standards.

18. In addition to fundamental research on climate, research priorities should consider needs of decision makers in areas related to both adaptation and mitigation.

19. For improved understanding of loss trends, there is a need to continue to collect and improve long-term and homogenous datasets related to both climate parameters and disaster losses.

20. The community needs to agree upon peer reviewed procedures for normalizing economic loss data.
1 The views expressed in this report are those of the participating individuals. Institutional affiliations are only provided for identification purposes.
2 http://www.grida.no/climate/ipcc_tar/wg1/518.htm
3 http://www.grida.no/climate/ipcc_tar/wg1/518.htm

Workshop Participants (full bios here in PDF)

Christoph Bals

Laurens Bouwer
Institute for Environmental Studies, Vrije Universiteit

Rudolf Brázdil
Institute of Geography, Masaryk University

Harold Brooks
NOAA National Severe Storms Laboratory

Ian Burton
University of Toronto, Meteorological Service of Canada

Ryan Crompton
Risk Frontiers, Macquarie University

Andrew Dlugolecki
Andlug Consulting

Paul Epstein
Center for Health and the Global Environment, Harvard Medical School

Eberhard Faust
Climate Risks, Department of Geo Risks Research/Environmental Management
Munich Reinsurance Company

Indur Goklany
Science & Technology Policy, Office of Policy Analysis
Department of the Interior

Maryam Golnaraghi
Natural Disaster Prevention and Mitigation Programme
World Meteorological Organization (WMO)

Hervé Grenier
Risk modelling and weather derivatives
AXA Reinsurance

Bhola R. Gurjar
Indian Institute of Technology, Department of Civil Engineering

Armin Haas
Potsdam Institute for Climate Impact Research

Jaakko Helminen
Climate Service, Finnish Meteorological Institute

Peter Höppe
Department of Geo Risks Research/Environmental Management
Munich Reinsurance Company AG

Claudia Kemfert
DIW Berlin
Department Energy, Transport and Environment

Richard J.T. Klein
Stockholm Environment Institute

Thomas Knutson
Climate Dynamics and Prediction Group
Geophysical Fluid Dynamics Laboratory/NOAA

Thomas Loster
Munich Re Foundation

Robert Muir-Wood
Risk Management Solutions

Gunilla Öberg
Centre for Climate Science and Policy Research, Linköping University

Roger Pielke, Jr.
Center for Science and Technology Policy Research, University of Colorado

Silvio Schmidt
GeoRisks Research Department, Munich Reinsurance Company
German Institute for Economic Research (DIW) Berlin

Gerd Tetzlaff
Meteorology, Universität Leipzig, Institut für Meteorologie

Hans von Storch
Institute for Coastal Research, GKSS Research Center

Koko Warner
Institute of Environment and Human Security, United Nations University

Martin Weymann
Sustainability & Emerging Risk Management, Swiss Reinsurance Company

Angelika Wirtz
Department of Geo Risks Research/Environmental Management
Munich Reinsurance Company AG

Anita Wreford
School of Environmental Sciences
University of East Anglia

Qian Ye
Center for Capacity Building, National Center for Atmospheric Research

Ricardo Zapata-Marti
Focal Point for Disaster Evaluation, ECLAC
CEPAL/México - Naciones Unidas