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Early Warning for Natural Hazard Mitigation
The Indian Ocean Disaster
of December 26, 2004 generated one of the strongest calls yet for early
warning systems for natural hazards. Despite the International Decade for
Natural Disaster Reduction and repeated calls for natural hazard warning
systems for all countries by 2000, disasters still occur without warning.
Constructing early warning systems, getting them working satisfactorily and
sustaining them at appropriate levels of operational efficiency and
effectiveness are unappreciated challenges. Even when scientific monitoring
and predictive capabilities exist, it may take up to several decades - and
huge dedication on the part of those responsible - to make warning systems
function well. And then the effort needs to be sustained.
Early warning systems consist of six main elements (Figure 1: Principal
components of natural hazard early warning systems) linked by
feedback loops (e.g. if a warning is not generating the desired response,
the warning needs altering). Design requires effective integration of
expertise from scientific and technical disciplines (e.g. meteorology,
geology), behavioral, sociological and organizational disciplines, and the
organizations which represent them. Where integration is poor, systems are
likely to under-perform. Mapping exposure of people and property to natural
events identifies those in need of warning. Investment in technical
monitoring, detection and forecasting capabilities extends warning lead
time. Building up the experience of those responsible for event detection
ensures that they recognize the conditions leading to unusually large
natural events.
Natural events often cross political and organizational boundaries and one
of the big challenges is effective sharing of environmental data. The
revolution in information and communication technologies (ICT) has opened up
an array of new methods, including the mobile telephone, for alerts and
warnings. The choice of ICT must be carefully matched to the levels and
types of technologies used in exposed communities and their socio-economic
characteristics.
Early warning systems will fail or under-perform without a high degree of
public awareness of hazards, hazard warnings and how to respond to warnings.
Creating and maintaining a high level of public awareness and responsiveness
through education is a huge task, especially where at-risk populations
include tourists with a limited understanding of local environmental risks.
A successful warning is one that is (a) sent (b) received and (c) recognized
and understood and acted on by the intended recipient. A frequent problem is
that senders believe their warnings are successful, when in fact warnings
are neither successfully received nor understood. Warning recipients bring
their own meanings and past experiences to the situation in which a warning
is received. Response is conditioned by present perceptions and past
experiences.
As an example, in February 1953, tidal flooding killed thousands in the
North Sea basin along the coastlines of Britain, The Netherlands and
Belgium. The flood struck in England several hours before it hit The
Netherlands and Belgium. If a warning system had existed, the English could
have warned the Dutch and Belgians as soon as they were flooded. This
example illustrates the potential of ‘in-event warning’ which could have
saved thousands of lives in the 2004 Indian Ocean earthquake and tsunami
disaster. In-event warnings must be developed as part of any natural hazard
warning system.
Reference
United Nations (2005) Draft Common Statement of the Special Session on the
Indian Ocean Disaster: Risk Reduction for a Safer Future, World Conference
on Disaster Reduction, Kobe, Hyogo, Japan 18-22 January.
Dr Dennis Parker is with the Flood Hazard Research Centre, Middlesex
University, London. He can be contacted at
D.Parker@mdx.ac.uk
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