FIFTH INTERNATIONAL WORKSHOP ON TROPICAL CYCLONES
Topic 5 TROPICAL CYCLONE IMPACTS
Topic Chair: Rex Falls
11 Manly St
Birkdale, QLD 4159
Topic 5.1 Societal Impacts
Co-Rapporteurs: James C. Weyman (USA),
Linda Anderson-Berry (Australia)
Topic 5.2 Economic Analysis
Rapporteur: R. J. Murnane (USA)
Topic 5.3 Effective Warnings
Rapporteur: T. C. Lee (Hong Kong, China)
Human suffering and economic losses are the common result of tropical cyclone landfall, and their impacts can have major social and economic ramifications in the countries affected. Tropical cyclone warning systems linked with reliable response systems are the central mechanism for the protection of life, and the reduction of avoidable losses. Yet understanding of the societal vulnerabilities is incomplete, and quantification of the attendant risks is sketchy. Long term mitigation measures such as the assurance of the adequacy of domestic structures, and land use changes, are equally important, but can be very difficult to achieve.
The three Working Group (WG) reports represent overlapping areas of interest and analysis. This report highlights the main findings of the WGs. Progress since IWTC-IV is highlighted; along with areas for discussion that will lead to recommendations.
5.0.1 Societal Impacts
The 5.1 Societal Impacts WG noted the essential role of a "total warning system", comprising accurate and timely tropical cyclone forecasts and warnings, efficient communication mechanisms to transmit the warning messages, and public education encouraging appropriate disaster preparedness and defensive actions, in empowering citizens to reduce their vulnerability and build community resilience. Along with hazard-risk and community-vulnerability assessments and the application of a social protection system, this total warning system is absolutely required to achieve sustainable development and to lessen the human and economic impacts of tropical cyclones. There is an increasing trend to holistic risk management approaches in disaster management, and societal risk analysis is recognised as a key stepping-stone to more effective total warning systems.
Great differences in the nature of the societal risk exist in different countries as illustrated in the 5.1 WG report by examples drawn from Australia, India, Bangladesh, China and the United States. The societal vulnerabilities also differ widely within regions, depending on both socio-economic and geophysical factors. Readers are urged to refer to the report of WG 5.1 for a fuller appreciation of the factors involved.
Whilst the potential for tropical cyclone disasters exists in all of the affected countries, the capacity for response to and recovery from cyclone impacts is quite different between more developed or affluent, and less developed countries. In less-developed countries, the impacts can threaten the very existence of an area by denying the people the capability to obtain the basic necessities of life, food and water. In developed nations with large, expensive coastal communities, industries, and infrastructure, the societal impacts are reduced because of insurance protection and reserves to fall back on. However, the impacts to the economies of all countries can be substantial.
The question scientists and decision-makers must ask is: What actions can be taken to reduce community vulnerability to tropical cyclones?. The first step in answering this question is to determine qualitatively and quantitatively, if possible, the vulnerabilities that exist. The next step is to develop short-/medium-/long-term strategies and plans to reduce these vulnerabilities. This is not an easy or quick solution, but the only one that will work in the long-term. The pressure on the total cyclone warning system to work near-flawlessly will grow as populations migrate into risky areas or repeat past mistakes with inadequate shelter unless effective long-term mitigation measures are put in place.
An understanding of the vulnerabilities of affected communities and the response options available can assist tropical cyclone warning system managers in ensuring warnings are suited to the needs of different communities and areas. Warnings need to take into account such variables as ethnicity, literacy, an understanding of response patterns including the lead times required for evacuations and sheltering requirements, to secure fishing fleets, and so on. This adaption of warnings needs to be done as a consultative process.
Draft discussion items
The 5.1 WG identified several public policy applications and social measures to identify and mitigate societal vulnerabilities to TCs:
a) Provide both the general public and policy makers with a higher level of tropical cyclone awareness education and training.
b) Invoke both quantitative and qualitative research methods to investigate and determine societal tropical cyclones vulnerabilities and meteorological variability so policy and decision makers can make informed choices on the effects of climate change, variability, and extreme weather events. Conduct behavioral studies that identify realistic assumptions of how the public will respond to cyclone threats. Ensure research results are useful, relevant, and focused and linked to users needs. Establish good decisions as the goal of research rather than good predictions, good theories, or good models.
c) Each country that experiences landfalling tropical cyclones should conduct quantitative assessments of the impacts on society ensuring that: the impacts are measured correctly and accurately; factors are not overlooked because of reliance on available quantitative information; the interrelation of atmosphere and societal trends that condition temporal or spatial patterns in impacts are considered; and the needs and vulnerabilities of ethnic and other groups previously under-represented in social and environmental sciences are included. These assessments should then be collected to form a global database of societal and economic impacts and vulnerabilities.
d) Establish good communications and research cooperation in the international research community, especially between physical and social scientists. Establish good communications and cooperation between researchers and the users that can benefit from this research. Ensure the common task of making good decisions to reduce vulnerabilities and risk is an integrated, common goal for research, public, media, and private sector communities.
e) At a national level strengthen communications and sharing of information among departments and agencies. Institute plans, arrangements, and mechanisms for agencies to effectively work together in preparedness, to reduce vulnerabilities, and to respond to impacts. Develop partnerships among government, non-government, amateur radio, and media agencies to ensure integrated, non-duplication response and preparedness activities.
f) Shift focus of disaster management from relief and response to comprehensive risk management aimed at reducing social vulnerability.
g) Establish good short-/medium-/long-term social and economic policies and programs designed to improve societal and environmental resilience to tropical cyclones and reduce the level of vulnerability by providing social protection and addressing the structural causes of tropical cyclone vulnerabilities.
h) Invest in strengthening and diversifying the sources of livelihoods of people in tropical cyclone prone areas. Capitalize and nurture the inherent social and cultural support capacities of poor communities and families. Systematically integrate poverty reduction and vulnerability reduction programs so people get out of poverty and cope better with tropical cyclone risks.
5.0.2 Economic Analysis
The 5.2 Economic Analysis WG examined a number of issues related to losses from TC landfall as one stop in a long-term effort to ameliorate the effects of tropical cyclones. Accurate estimates of economic losses from TCs and other natural disasters would help emergency management, planners, governments, and businesses to plan and cope with TCs and other natural disasters. Further, a knowledge of the costs and benefits of disaster mitigation options is required to support these efforts. Specifically, a knowledge of the costs of preparations, and the losses avoidable through response to warnings, is of immediate interest to tropical cyclone warning and response authorities.
Progress since IWTC-IV:
a) Trends and methodology
The group referred to studies in the United States on the normalisation of historic costs and losses to present day values and populations. In Australia, there has been an increase in risk studies that may potentially be used for economic assessments, and a very limited number of economic assessments. A Natural Disasters Risk Management Studies Program has been established supported by the three levels of government. A manual "Disaster Loss Assessment Guidelines" has been issued. A project is also underway to develop a new data base system about typhoon activity, disasters, and social impacts in Japan.
The WG provided a number of useful definitions: economic losses, economic costs, cost normalisation, direct and indirect losses, avoidable and unavoidable losses.
b) International Data Base on Losses and Costs of Natural Disasters.
This recommendation has not been acted on, although work underway in some countries could ultimately provide input to such a data base, if established.
c) Literature review.
A final recommendation of the group was the establishment of a working group of experts to review the international and national literature on the economic and social aspects of tropical cyclones worldwide. The working group would use the historical data to predict future economic and social losses and costs and assess the ability of tropical cyclone warning and information systems to reduce damage. This recommendation has not been acted on.
International Data Base on Losses and Costs of Natural Disasters and Expenses of Mitigation
It is important to gauge the economic value of tropical cyclone warning and information systems. A cost-benefit analysis will need accurate statistics on the costs and losses of past events as well as the expenses for tropical cyclone warning and information services and for mitigation efforts. The losses and costs of past events will need to be normalized to account for changes in population, wealth, and inflation.
We encourage the WMO to promote the development of an international data base that would track the losses and costs of tropical cyclones as well as the expenses associated with tropical cyclone warning and information services and mitigation efforts.
Enhanced Tropical Cyclone Best-Track Data Sets
Best track data sets provide basic input to risk models. Additional storm characteristics such as the radius of maximum winds, maximum gusts, and rainfall would improve the depiction of tropical cyclones in risk models. Such a best-track data set has been produced for the Atlantic after a reconstruction of many historical storms. At the 34th Session of the ESCAP/WMO Typhoon Committee a small Working Group was formed to produce a detailed proposal for the development of a unified Northwestern Pacific Tropical Cyclone Best-Track Data Set. The plan would be submitted to the Typhoon Committee at their 35th Session for their consideration. We encourage the extension of this effort to all regions subject to tropical cyclones.
Parametric Wind Field Model
Parametric wind models form the basis of the tropical cyclone hazard component of many risk models. Recent wind field observations collected with Global Positioning System (GPS) dropsondes have many characteristics that are not represented by standard parametric models.
The Analysis sub-group of the Tropical Cyclone Prediction Group from IWTC-IV encouraged the development and testing of parametric models. We agree with this and also encourage the development and testing of next-generation parametric wind models.
5.0.3 Effective Warnings
An effective TC warning system requires the warnings and information prepared by the National Meteorological Services/Tropical Cyclone Warning Centres to be accurate, disseminated to the designated users in a timely and comprehensive manner, and responded to in the most effective manner by the emergency organizations and communities at risk. This end-to-end approach is called a "total warning system." The WG considered factors affecting the effectiveness of a TC warning system under four main areas:
a) Forecast Accuracy and Reliability
There has been considerable progress in TC track forecasting, with ensemble approaches showing promise of further improvements. Critical short-range forecasts for the 12h period prior to landfall are still prone to unacceptable errors as illustrated by examples provided for Hong Kong.
The 5.3 WG strongly encouraged special efforts to improve the track forecasting of land-falling TCs by taking full advantage of new sources of remotely sensed data.
There is a continuing need for improvements in TC intensity prediction, and the WG strongly encouraged special efforts to improve intensity predictions, particularly in the critical hours before landfall.
b) Warning Dissemination and Presentation
The advances and proliferation of internet and mobile communication technology in several countries has very considerable beneficial impact on warning dissemination and information exchange in several countries. Graphical products that improve public understanding have been developed, and are very popular.
Although the internet is growing fast, there is still a large population without internet access. Care must be taken to ensure that the quality of TC warnings is not polarized into those who have access to the internet and those who do not. Further, the internet is flooded with information from many different sources, and it is a non-trivial task to ensure official warnings are conveyed to the public without the confusion of conflicting opinions.
c) Warning Response, Public Education and Disaster Preparedness
Many NMSs are consciously putting more effort into user-oriented approaches alongside of their strong science traditions. Nurturing partnerships with the media and emergency services is seen as an integral part of this outward looking strategy. As a consequence, the NWS involvement with multi-disciplinary approaches to cyclone risk assessment and management mechanisms is becoming more common-place.
d) International and Regional Cooperation
The WMO system provides indispensable unifying linkages between countries, which facilitate co-operation and exchange of information. Specifically, the WMO Global Telecommunications System continues to play a very important role in the exchange of warning information.