Disaster Risk Reduction Under Changing Climate Conditions: Roles
for the National Meteorological and Hydrological Services
Heather Auld
Adaptation and Impacts Research Division
Atmospheric Science and Technology Directorate
Environment Canada
Toronto, Canada
ABSTRACT
Evidence from around the world indicates that the costs of weather related disasters are increasing over
time, in spite of greater disaster awareness. The rising losses, even under current climate conditions,
point to a need for comprehensive disaster risk reduction actions for weather and climate hazards that
support all pillars of risk reduction. Effective management of disaster risks requires coordinated and
comprehensive integration over the four pillars of risk reduction: Risk Management actions consisting of
(1) disaster prevention or mitigation and (2) disaster preparedness, and Crises Management actions
through (3) emergency response and (4) recovery actions and plans.
The need for more comprehensive disaster risk reduction programs, products and services is likely to
grow as the climate changes. While changing climate and weather extremes add significant challenges to
this process of disaster risk management, adaptation steps taken today to reduce the impacts of hydrometeorological hazards also provide opportunities for regions to become better prepared for future
climate change.
INTRODUCTION
Evidence from around the world indicates that the
costs of weather related disasters are increasing
over time. Since the decades of the 1950s, the
annual direct losses from natural catastrophes in
the 1990s increased 14 times, rising from US$3.9
billion to US$40 billion a year using 1999 dollars
(Munich Re, 2005; IPCC, 2001), while population
grew only by 2.4-fold. In reality, these losses are
larger by a factor of two, when losses from less
severe weather-related events are included.
Of these rising losses, hydro-meteorological
hazards from weather, climate and water events
such as floods, droughts, tropical cyclones, heat
waves and severe storms account for the majority.
In fact, hydro-meteorological hazards accounted
for close to 90 per cent of the lives lost in natural
disasters during the last decade (WMO, 2004).
Over the last 30 years, the number of lives lost to
natural disasters declined and levelled off at about
80,000 per year, while the number of people
affected and the estimated economic losses have
been steadily increasing. While the debate
continues on whether increases in climate extremes
are contributing to the escalating disaster losses, it
is known that changing socioeconomic and
demographic trends have also contributed to the
rising trends and vulnerabilities (IPCC, 2001).
While it is normal to expect large year-to-year
variations in the number and intensity of natural
hazards, it is not normal for the costs of natural
hazards to continue rising over time. When a
natural hazard becomes a disaster, the result is as
much as function of the way that the community
does business or adapts to the hazard as it is of the
natural hazard itself. The fact that both insured and
uninsured losses have been rising rapidly in
constant monetary terms reflects a failure of
communities and society to adapt well enough to
current climate variability and extremes.
MEASURES TO MANAGE RISKS AND
VULNERABILITIES
National Meteorological and Hydrological
Services (NMHSs) have two windows to act in the
disaster risk management process: (i) before
disasters, through disaster prevention and
emergency preparedness (risk management); and
(ii) imminently before, during and after disasters in
support of disaster relief, recovery and
reconstruction (crises management). Effective endto-end management of disasters requires the
coordinated and comprehensive integration of the
four pillars of action, as shown in Figure 1: (1)
disaster
risk
mitigation,
(2)
emergency
preparedness, (3) emergency response and relief,
and (4) disaster recovery and rebuilding actions.
The combination tries to minimize existing
vulnerabilities, prevent adverse impacts and to
ensure that comprehensive plans are in place to
react to emergencies and recover from disaster
impacts (ISDR, 2002).
In most countries, natural hazard policies
traditionally focus on actions that minimize the
impacts during a disaster and provide immediate
relief and support to victims. Although disaster
response is important, it fails to address the causes
of disaster losses. The World Bank has estimated
that every dollar spent in preparing for a natural
Hazards; climatic
information
Forecasts;
Risk
guidance
disaster saves seven in response (World Bank,
2004). During the 1990s, for example, the World
Bank estimates that economic losses due to natural
disasters could have been cut by US$ 280 billion
through just US$ 40 billion of appropriate advance
spending.
NMHSs are well-placed to support all the pillars of
disaster risk management, including: provision of
hazards information for community risk impact
assessments and land use planning; improvements
to climatic design information for safer
infrastructure; development of environmental
prediction products and risk guidance so that
potential impacts and risks can be better
interpreted; monitoring to detect hazards and
emerging threats; dissemination of forecasts and
timely early warnings for operational emergency
response actions; assistance in risk management
education and community capacity building; and
provision of forecasts and risk guidance for
recovery operations, including changing climate
risks for rebuilding and recovery.
Risk
management
Crisis
management
Emergency
Planning;
Warnings
Forecast
support
Figure 1: NMHS’s riles in Disaster/Emergency Management Systems and its four
pillars: Prevention, Preparedness, Emergency Response and Recovery or Risk Management
and Crisis Management.
HAZARD AND VULNERABILITY
ASSESSMENTS
There is a saying: “forewarned is forearmed. When
we know the threats we face, we are better able to
prepare for them” (Dr. Klaus Töpfer - UNEP
Executive Director). Although natural disasters
are not always predictable, they are most often
foreseeable and can be planned or risk managed
ahead of a disaster. Many natural hazards can be
foreseen, or anticipated using past experience,
climatological analyses of atmospheric hazards,
analysis of vulnerabilities including current land
uses and forensic analyses.
2
A very critical part of a disaster risk management
strategy is the completion of a Vulnerability or
Hazards Identification and Risk Assessment
Process (HIRA) that integrates the probability of
hazards in a region with critical infrastructure
vulnerability and risk assessments. As illustration,
two provinces in Canada have passed legislation
requiring that all municipal and regional
governments adopt emergency management
assessment and planning (Auld et al, 2006). The
province of Ontario passed its provincial
Emergency Management and Civil Protection Act
legislation in April 2003, requiring all municipal
and regional governments in the province to
identify and assess various hazards and risks to
public safety that may give rise to an emergency
situation (Government of Ontario, 2003). The Act
requires that a HIRA process be completed and all
priority hazards be assessed, that vulnerable
groups, infrastructure and likely risks be
prioritized, potential interventions be identified and
comprehensive disaster management planning
adopted (Auld et al, 2006).
The risk assessment process is needed to determine
how often and how severe the impacts to public
safety could become and relies heavily on hydrometeorological information and tools. In response
to municipal demands for hazards information to
meet this HIRA process, Canada’s Meteorological
Service and its provincial government partner,
Emergency Management Ontario, developed a web
site (www.hazards.ca) and publication on
atmospheric hazards that allows regional
emergency managers to access climatological
hazards information, customize atmospheric maps
for their localities and to overlay regional
combinations of hazards maps (Auld et al, 2002).
The website and publications contain peerreviewed or “defensible” maps of various hydrometeorological hazards and climatological trends,
Weather Warning criteria and guidance on
potential impacts of specific hazards, including
extreme heat and cold, drought, extreme rainfall,
blizzards, hurricanes, ice storms, tornadoes, wind
storms, smog, UV radiation, etc (Auld et al,
2006a). The website highlights the probability of
occurrence of each hazard and compares the
relative frequency of these hazards across various
regions of Ontario. The web site also includes a
feature allowing users to assess multi-hazard risks
using co-recognition software and “stacking" maps
together in order to align places on the different
maps, even though maps might have different
scales and projections.
All maps included in the Hazards collection used
for Ontario needed to be scientifically defensible
(e.g. journal publications, data meeting WMO
requirements for weather data archiving and
analyses). Ideally, these maps, graphs and
information should be assembled, assessed by
theme and accompanied by documentation
describing its information holdings, the data used
to develop the mapped fields, methodologies,
uncertainties and limitations for use of the maps
and references.
New and evolving threats (e.g. changing climate
hazards, pandemics) also needed to be considered
in the HIRA process. Where trends existed, the
record and analyses from the past 15 years was not
considered sufficient for the risk assessment. For
these cases, historical trends as well as climate
change scenarios were developed to highlight
hydro-meteorological
variables
where
the
frequency and risks from specific hazards were
known to be increasing.
The Canadian experience showed the importance
of having hazards information that meets the
emergency and disaster management planning
needs of a wide variety of users. A significant
challenge remains the need to communicate
scientific information on hazards simply to all
users, including the non-technical users responsible
for emergency planning, and to ensure that the
information remains scientifically defensible.
FAILURE OF INFRASTRUCTURE AND
DISASTER RISK REDUCTION
It has been said that “the house is the first line of
defense against hazards”1. In future, better early
warnings of impending disasters may benefit from
links to critical thresholds for infrastructure failure.
Structural failures can result when climate
extremes approach their design values and the
engineering performance of the structure
1
4th World Water Forum, Dec 10, 2005;
Framework theme 5
3
encroaches or exceeds uncertainty limits (Auld et
al, 2006b). Forensic studies have shown that,
above critical thresholds, small increases in
weather and climate extremes have the potential to
bring large increases in damage to existing
infrastructure. These studies indicate that damage
from extreme weather events tends to increase
dramatically above critical thresholds, even though
the high impact storms associated with these
damages may not be much more severe than the
type of storm intensity that occurs regularly each
year (Munich Re., 1997; Swiss Re., 1997;
Coleman, 2002). In many cases, it is likely that the
critical thresholds reflect storm intensities that
exceed average design conditions for a variety of
infrastructure of varying ages and condition.
An investigation of claims by the Insurance
Australia Group (IAG), as shown in Figure 2,
indicates that a 25% increase in peak wind gust
strength above a critical threshold can generate a
650% increase in building claims (Coleman, 2002).
Similar studies indicate that once wind gusts reach
or exceed a certain level, entire roof sections of
buildings often are blown off, or additional
damages are caused by falling trees. Typically,
minimal damages are reported below this threshold
(Munich Re., 1997; Swiss Re., 1997; Freeman and
Warner, 2001; Coleman, 2002). Similar results
have been obtained for flood and hailstone
damages. This information on thresholds for
widespread infrastructure failure needs to be
incorporated into weather warning criteria and
considered in updates to climatic design values
used in construction codes and standards.
Climatic design values that are used for the design
of reliable and economical infrastructure include
quantities like the 10, 50, or 100 year return period
“worst storm” wind speed, rainfall or snow
conditions that are typically derived from historical
climate data. Almost all of today’s infrastructure
has been designed using climatic design values that
have been calculated using historical climate data
and assuming that the average and extreme
conditions of the past will represent conditions
over the future lifespan of the structure. While this
assumption has worked in the past, it will hold less
as the climate changes.
The climatic design
values used in codes and standards of today need
to reflect these changing climate conditions and
need to be assessed regularly against regional
climate trends to determine whether existing
margins of safety for structures have any
remaining tolerances to accommodate increases in
climate loadings.
IMPROVING WEATHER WARNINGS
FOR EMERGENCY RESPONSE:
MOVING FROM WEATHER
PREDICTION TO RISK AND IMPACTS
PREDICTION
One of the most effective measures for disaster
readiness and emergency response is a wellfunctioning early warning system that delivers
accurate information dependably and on-time.
Warnings buy the critical time needed in response
to hazards to evacuate populations, reinforce
infrastructure, reduce potential damages or prepare
for emergency response.
All too often, warnings are issued without the
NMHSs having an appreciation of the relative
severity and potential impacts of the forecast
severe weather event. As a result, warnings can,
and frequently do fail for any of four primary
reasons (UNISDR, 2001). These include: (1) a
failure of forecasting, such as an inability to
understand a hazard or a failure to locate it
properly, in time or space; (2) an ignorance of
prevailing conditions of vulnerability, determined
by physical, social, or economic inadequacies; (3)
a failure to communicate the threat accurately or in
sufficient time; and finally, (4) a failure by the
recipients of a warning to understand it, to believe
it or to take suitable action.
The success of an early warning depends on the
extent to which it triggers effective response
measures. Warning messages need to suggest the
appropriate actions that those at risk should take.
This is difficult when information is incomplete,
when there are conflicting recommendations or
when the liability of the NMHS is of concern.
Because emergency responders often are unable to
translate the scientific information on atmospheric
and hydrological hazards in warnings into risk
levels and thresholds for response, future work is
needed that can identify the most dangerous
impacts, consider the contribution of cumulative
and sequential events to risks (e.g. antecedent
4
Figure 2. Building claims as a function of peak gust speed (Australia).
Source: (Coleman, 2002).
rainfall accumulations) and determine the
meteorological thresholds linked to risks for
infrastructure, communities and disaster response.
These shortfalls are leading some NMHSs to
consider Environmental Prediction Programs to
move weather and hydrological forecasts towards
impacts and risk forecasts. This step requires a
greater investment in the science of impacts in
order to translate the intensity of forecast
meteorological parameters into potential risk
levels. The incorporation of breaking points for
infrastructure into warning systems, for example,
could be used to highlight differences between
weather events that could prove disruptive
compared to those likely to require widespread
emergency response actions.
Several NMHSs are investigating tiered or
escalating warning systems to differentiate
potential impacts, to varying degrees. For example,
MeteoFrance is investing in a Meteorological
Vigilance system that works with four levels of
hazard warning and has resulted in new hazards
being added to their system (e.g. heat wave
warnings).
The
European
Multi-services
Meteorological Awareness (EMMA) Program is
based on MeteoFrance’s Meteorological Vigilance
system and uses a similar four-colour code, using a
corresponding risk awareness level to highlight the
most dangerous events (Gérard, 2002). China uses
a colour-coded warning system for 11 extreme
weather conditions including typhoons, rainstorms,
heat and cold waves, fog, sandstorms, lightning
storms, gales, hailstorms, snowstorms and road
icing. Here, warnings are labelled blue, yellow,
orange and red in an ascending order matching
national standards of seriousness. The increasing
levels of warning severity require escalating
actions. For example, shops are to remain closed
and classes suspended if typhoon warnings change
from orange to red. A red warning for rainfall
intensity means emergency squads must be ready
for rescue operations as rainfalls are expected to
reach 100 millimeters or higher in 3 hours, creating
the possibility of floods. In the United States,
NOAA is piloting a project in Florida to present
daily hazards forecasts in graphical format by
relative “degree of threat” (Sharp et al, 2000).
Increasingly, studies are highlighting the risks
from less “traditional” weather events. These
events or “creeping hazards” often result from
cumulative or sequential multi-hazard events that
also enhance vulnerabilities to disasters (e.g.
drought, waterborne disease potential). For
example, flooding events can result from smaller
rainfall events if amounts have been preceded by
five days of antecedent rainfall and saturated
ground conditions. As a result, specific criteria for
issuing rainfall warnings benefit when antecedent
rainfall and ground conditions are considered
before deciding to issue a warning.
Whether addressing fast or slow onset hazards,
more effective early warning systems must provide
adequate lead times for the activation of
emergency response plans and identification of the
most significant risks. The U.K. Meteorological
Office, for example, currently provides Early
Warnings of potentially disastrous weather events
to emergency responders up to five days in
advance so they can be prepared for the effects of
potentially high impact weather. Because
prediction of severe weather at this range in any
detail is difficult, these Early Warnings are
expressed in terms of probabilities, with warnings
issued when the probability of disruption due to
severe weather somewhere in the UK is 60% or
more (U.K. Meteorological Office, 2004).
CLIMATE CHANGE
The climate is changing globally and regionally
and will continue to do so, even with the most
ambitious of mitigation successes. One of the most
threatening aspects of global climate change is the
likelihood that extreme weather events will
become more variable, more intense and more
frequent as storm tracks shift and storm
frequencies and intensities increase regionally. A
report by the United Nations Environment
Programme’s (UNEP) financial services initiative
anticipates that the global cost of natural disasters
will top US$300 by the year 2050 (ISDR, 2004) if
the likely impacts of the changing climate are not
countered with aggressive disaster reduction
measures.
Adaptation steps taken today to reduce the impacts
of weather hazards will provide opportunities for
regions to become better prepared for future
climate change challenges. As a first step to
reducing climate change disaster risks, a “no
regrets approach” that reduces vulnerability to
existing hazards becomes an even more effective
strategy for reducing future risks. The barriers to
managing the risks associated with current climate
variability are the same barriers that will inhibit
regions and nations in addressing the future
increases in the complexity and uncertainty of risk
due to climate change (UNDP, 2004).
THE FUTURE
The implementation of disaster reduction strategies
poses global challenges today and for the future.
While the 1990-1999 UN International Decade for
Natural Disaster Reduction (IDNDR) was
dedicated to promoting solutions to reduce risk
from natural hazards, the decade ended with more
disasters, involving greater economic losses and
more human dislocation and suffering than when it
began (ISDR, 2004). As a successor to the
IDNDR, the UN General Assembly founded the
International Strategy for Disaster Reduction
(ISDR) in 2000 to continue the promotion of work
and commitment in disaster reduction. The ISDR
has worked to shift its primary focus from hazards
and their physical consequences to greater
emphasis on the processes involved in
incorporating physical and socio-economic
dimensions of vulnerability into the wider
understanding, assessment and management of
disaster risks (ISDR, 2004).
The WMO supports the achievement of the
international Millennium Development Goals to
“halve the loss of life associated with natural
disasters of meteorological, hydrological and
climatic origin” and accordingly, has set a target to
reduce by 50 per cent over the next 15 years the
10-year average fatalities (relative to 1994-2003)
from all natural disasters related to weather,
climate and water (WMO, 2005). WMO and its
NMHSs have the capability to develop and deliver
critical products and services to the entire disaster
risk management decision process. These include
the multidisciplinary science to understand the
vulnerability of communities to weather-, climateand water-related hazards using historical records,
climatic design values and climate projections
from NMHS. Similarly, WMO's early warning
systems can provide communities with the
information needed to activate disaster plans in
time to protect life and minimize economic losses.
These systems need to operate alongside
educational and capacity-building services that
help ensure nations can move decisively to better
protect lives and property against natural hazards.
Without the existing preventative services through
NMHSs, it is sobering to think that the disaster
statistics on loss of life and property during the
6
International Decade for Natural Disaster
Reduction likely would have been even higher than
the current values show (Golnaraghi, 2004). But, in
future, changing climate conditions will likely
translate into more frequent occurrences of
extreme weather in one form or another. Without
aggressive disaster management actions, it is likely
that new and unexpected vulnerabilities will arise
from unfamiliar hazards. In the end, surprise has
the potential to become the biggest killer. Prudent
planning for disaster risk management should
therefore factor in current and future risk reduction
adaptation actions to current and evolving hazards
and risks.
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