CLIMATE CHANGE RISK ASSESSMENT
GUIDELINE
PURPOSE
Main Roads is proactively looking to protect our asset against the potential risks of climate change
and in doing so, ensure the future integrity of the road network into the future. This document
outlines what additional consideration should be given when planning, designing and maintaining
road and bridge infrastructure, to take account of the anticipated impacts of climate change.
Network managers, strategic and project planners and designers, will need to apply more extensive
probabilistic investment analyses and design approaches, in order to trade off the costs of making
the infrastructure solution more robust versus the economic costs of future disruption or failure.
Application
Who should use this document?
Those involved with the planning, design and maintenance of Main Roads’ infrastructure, including,
but not limited to:
 Road Planners;
 Road Designers
 Project Managers;
 Asset Managers; and
 Contract Managers.
Responsibilities
Project Managers are responsible for ensuring that the implications of a changing climate have
been assessed as part of project development and that the risks are both understood and have
been discussed with the relevant Asset Manager for their input.
Why should I use this document?
The use of this document manages corporate risk by assisting to identify climate change risks
relevant to a particular project leading to the development of appropriate treatments.
What does this document apply to?
Climate Change considerations are applicable to all stages of planning, developing, constructing
and maintaining a road project including associated works such as bridges, culverts, etc.
CURRENT SITUATION
There is strong scientific evidence to suggest that climate change is occurring. Scientists believe
that changes like sea level rise, changed weather patterns, and increasing temperatures are already
occurring globally and will accelerate. While changes in climate are set to continue throughout this
century and beyond, impacts are of concern in existing planning and design time-scales.
Climate change is predicted to have a significant impact on transportation, affecting the way we
plan, design, construct, operate, and maintain our infrastructure. Decisions taken today, related to
the redesign and retrofitting of existing infrastructure, or the location and design of new
infrastructure, will affect how well our network is able to adapt to climate change into the future.
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Focusing on the problem now will help reduce the likelihood of costly future investments and
disruptions to operations to accommodate climate change.
Main Roads is determined to play a lead role in responding to the challenges and opportunities
associated with climate change and will progressively review its Standards, Guidelines and Policies
to address these. Fundamentally our response will be to employ a ‘what if’ scenario approach to
decision making, to better appreciate risks that might be placed on current and future infrastructure,
and to incorporate greater flexibility to accommodate change where appropriate to do so.
KEY CLIMATE RISKS
We face four key climate change risks:
 generally higher temperatures, and more rainfall in the north and less rainfall in the south
 increases in the frequency, duration and magnitude of extreme heatwaves
 increased intensity of storms
 sea level rise.
These climate risks can impact our network in a number of ways:
 Inundation of coastal and estuarine assets
 Increased fatigue rates of pavement due to increasing temperature and moisture fluctuations
 Threat of asset failure i.e. due to material displacement by flooding
 Reductions in asset demand in drying areas such as the Wheatbelt
 Increases in asset demand in the areas getting wetter such as in the tropics
CURRENT STANDARDS
It is now a requirement that the implications of a 300mm sea level rise (450mm for structures) be
considered as part of planning, design and construction considerations for all rehabilitation and
expansion projects near coastal areas. These requirements are described in the Main Roads
internet site under Standards & Technical / Roads and Traffic Engineering / Climate Change. It is
now a requirement that this assessment be confirmed in all Design Reports.
That website also refers to the implications of Rising Temperatures in relation to bridge structures
and sprayed seals.
Not yet considered within our standards are the possible effects due to increases in frequency,
duration and magnitude of extreme heat waves; and increased intensity of storm events. Models to
help predict what can be expected are yet to be developed thus a risk management approach to
how these scenarios are considered for projects is to be adopted. It should be noted that the
Australian Rainfall & Runoff publication is currently being rewritten to include discussion in relation
to the uncertainties associated with emerging climate change affects. It is due for completion in
2013.
APPROACH TO CLIMATE CHANGE RISK ASSESSMENTS
The general approach to Climate Change Risk Assessment is to be as follows:
1. Determine environmental factors that influence project design and that are subject to climate
change
2. Assess the risk that these Environmental Factors present for design life of the asset and the
required Level of Service into the future
3. Determine adaptation treatment for project design
4. Secure funding for adaption treatment where this will require investment beyond the
previously approved funding limit.
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Determine environmental factors that influence project design and that are subject to climate
change
Consider the various environmental factors that may change over time and how these may affect
the design and operation of the asset. For example:
Environmental Factor
Temperature
Wind
Rainfall intensity
Rainfall
Sea Level
Waves
Water Table
Design Element
Expansion joints, sprayed seal, revegetation
Street light poles, Signs
Floodways, Bridges, Abutments, Drainage
Revegetation
Alignment, Bridges, Walls, Base, Sub-base
Abutments, Seawalls
Base, Sub-base, Drainage
Assess the risk that these Environmental Factors present for the design life of the asset and
the overall Level of Service
This step will help to identify when (a) the level of service is likely to fall below acceptable economic
limits; and (b) when the asset could be expected to incur significant damage due to changes in the
climate. The likely consequence from Climate Change on different design elements will help to
determine the most suitable treatment initially, and highlight future (staged?) provisions that may be
required in the future.
LIKELIHOOD OF ENVIRONMENTAL FACTOR CHANGING
BEYOND DESIGN TOLERANCES
1 – Rare, 2 – Unlikely, 3 – Moderate, 4 – Likely, 5 – Almost Certain
Consequences
5 – Catastrophic
4 – Major
3 – Moderate
2 – Minor
1 – Insignificant
1
2
3
4
5
5
H
H
H
VH
VH
4
M
H
H
H
VH
3
M
M
M
H
H
2
L
L
M
H
H
1
L
L
L
M
M
Risk Rankings
VH
LEVEL
DESCRIPTOR
FREQUENCY
Very High
1
Rare
Less than once in 20 years, <1%
H
High
2
Unlikely
At least once in 10 years, 5%
M
Moderate
3
Moderate
At least once in 3 years, 50%
L
Low
4
Likely
At least once per 1 year, 95%
5
Almost certain
More than once per year, >99%
Guide for consequence rating for asset
Infrastructure
Degree of damage
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Economic
cost
Disruption of
service
Social value
Safety
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extreme
economic cost
service completely
stopped until asset
is replaced
medium to long term loss of
access, amenity, aesthetics
and/or cultural value to or of
asset eg loss of access to
communities and services
chance of death or
severe irreversible
disability to a
person
major damage of the
asset, significant
repairs required
high economic
cost
major disruption of
service until asset is
repaired
short term loss of access,
amenity, aesthetics and/or
cultural value to or of asset
associated with necessary
activities
chance of
irreversible injury
MODERATE
(score = 3)
moderate damage of
the asset, repairs
required
average
economic cost
some disruption of
service until asset is
repaired
short term loss of access,
amenity, aesthetics and/or
cultural value to or of asset
associated with regular
activities
chance of
moderate,
reversible injury
MINOR
(score = 2)
minor damage of the
asset, monitoring
required to ensure it
does not worsen
low economic
cost
little disruption of
service
short term loss of access,
amenity, aesthetics and/or
cultural value to or of asset
associated with occasional
activities
chance of minor,
reversible injury
INSIGNIFICANT
(score = 1)
negligible damage
negligible cost
no disruption of
service
short term difficulty/decrease
in access, amenity,
aesthetics and/or cultural
value to or of asset
negligible safety
issue
CATASTROPHIC
(score = 5)
total and permanent
loss or damage,
replacement required
MAJOR
(score = 4)
Determine adaptation treatment for project design
These are treatments that can generally be considered as being additional to conventional
treatments:
1.
2.
3.
4.
Build for end of design life scenario
Planned adaptation
Progressive Modification
No Adaptation or Redundancy
Adaptation
Treatment
Build for end
of design life
scenario
Description
Planned
adaptation
Plan an upgrade program to
progressively adapt the
infrastructure as climate
change occurs. Initial design
considers predicted climate
changes and provides
functionality to adapt the
infrastructure at another time.
Consultation with program and
Build to maintain standards and
level of service for the climate
change scenario expected at
end of life
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Expected Financial
Implication
Potentially High
Upfront Costs,
although no further
costs for adaptation
are required. Provides
a higher level of
service for entire
design life. Risk that
actual climate change
will exceed prediction
Moderate Upfront
Costs expected,
although further
investment is required
during infrastructure
life cycle. Provides
some increase in level
of service.
Example
Culvert is designed
and constructed with
capacity for climate
change.
Culvert is designed
and constructed for
mid-life span climate
change conditions but
considerations made in
current design for an
upgrade in capacity ie
second culvert can be
installed in parallel.
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Progressive
Modification
(existing
asset)
No Adaptation
/ Redundancy
asset managers required to
secure investment program.
Redesign and reconstruct as
required and as possible in
response to verified climate
change as part of existing
maintenance regime or project
upgrades. Future verified
climate changes will be
captured in investigatory
criteria of audits.
No adaptation or making the
overall asset redundant as
there are suitable alternatives
or the asset is not required
Moderate upfront costs
expected. Further
climate changes will
force re-design. Higher
costs to adapt asset in
long term. Maintains
level of service.
Culvert is constructed
according to current
climatic conditions
(assume standards
may not be current).
Culvert will be
upgraded if needed in
future.
No extra investment
required.
Culvert is not
constructed at all or
not replaced when it
fails.
Network Managers, strategic and project planners and designers, will need to apply more extensive
probabilistic investment analyses and design approaches, in order to trade off the costs of making
the infrastructure more robust versus the economic costs of disruption or failure.
Accordingly, consideration also needs to be given to a No Adaptation scenario whereby the asset
owner would accept current standards for design and accept the risk of future damage due to
climate variability. This would potentially reduce the initial cost but may result in much higher future
costs due to community disruption and the difficulties of implementing improvements under future
traffic and climatic conditions.
Secure funding for adaption treatment where this will require investment beyond the
previously approved funding limit
The final step of the Climate Change adaptation process involves assessing the adaptation
treatments available to the project, as determined in the previous step. The project manager, in
consultation with the project team, asset managers, key decision makers and external stakeholders
assess the proposed treatments against life cycle cost, value for money, budgetary constraints and
social and environmental factors. It is here that treatment is decided for the project. In general the
principle of ‘as low as reasonably practicable’ for risk control should be applied. If necessary,
additional funding may need to be secured.
PROCEDURE FOR CLIMATE CHANGE RISK ASSESSMENT
A two tiered approach to risk assessment is to be adopted:
1. An initial assessment identifies the more obvious potential risks within each project to allow
for simple treatment planning and implementation. All projects should undergo an initial
assessment
2. A detailed analysis is used where more complex assessment (and external stakeholder
input) is needed to determine what precise form of treatment to adopt.
Initial Assessment
1. Has a risk assessment already been conducted by another project in the region?
2. If yes, consider relevance and timing of assessment and use to determine treatments.
3. If no, conduct an initial assessment
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Establish the context by:
 Defining the project to be assessed and the scope of the assessment
 Clarifying explicitly the objectives of the project
 Identifying the stakeholders (regional managers, asset managers) and their objectives and
concerns
 Establishing success criteria against which risks to the project objectives can be evaluated
(e.g. level of service; initial versus whole of life costs)
 Developing key elements of project (ie design elements) as a means of structuring the
assessment
 Determine relevant climate change scenarios for the assessment
Identify the risks by:
 Describing and listing how climate changes impact on each key element of the project
(design elements)
Analyse the risk by:
 Reviewing the controls, management regimes and responses already in place to deal with
each specific risk ie standards, or existing risk assessment treatments
 Assess the consequence of each risk against the project objectives and success criteria,
taking into account the extent and effectiveness of existing controls
 Forming a judgement about the likelihood of each identified risk leading to the consequence
identified
 Consider the risks in conjunction with the risks assessed for adjacent road sections or other
structures on the link under construction
 Determine the level of risk to the project for each of the climate change scenario used in the
analysis.
Evaluate the risks by:
 Re-affirming the judgements and estimates
 Ranking the risks in terms of their severity
 Screening out the minor risks that can be set aside and which would otherwise distract the
attention of decision makers and stakeholders
 Identify those risks for which more detailed analysis is recommended
Treat the risks by:
 Identifying relevant treatments to manage or adapt to the risks and their consequences
 Selecting the best options, incorporating these into forward plans and implementing them
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Detailed Analysis
1. Adopt this level of assessment for Major Projects and target scope for a broader context than
just the project ie regional context.
2. Follow the steps of the initial assessment but seek additional data density and/or broaden
collaboration to external stakeholders to the project (local government, utilities, land owners
etc) in reaching a solution both immediate and long-term.
FURTHER SUPPORT
Question relating to…
Risk Management
Procedure
Climate Change
Sea Level Rise
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Contact
Manager Legal and
Commercial Services, or
Manager Business
Performance
Manager Road Traffic
Engineering, or Project
Officer Sustainability
Manager Road Traffic
Engineering
Intranet site / TRIM document
Online Documents
Sustainability
D11#301668
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