Climate is changing… So the way we manage roads needs to change as well

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Photo: Christopher R. Bennett/World Bank
Few things are more depressing than seeing the damage caused by cyclones on transport infrastructure. Especially when it is a causeway that was only formally opened less than one month before the storm. That is what I found in early 2014 when participating in the Tonga Cyclone Ian Post Disaster Needs Assessment. The cyclone was a typical example of the heavy toll that climate change is taking on transport infrastructure, particularly in the most vulnerable countries.

Engineers are taught that water is the greatest enemy of transport infrastructure, and unfortunately climate change is leading to an increase in floods and storms, especially within the South-East Asia region. For example, the figure below shows the number of floods and storms for some Asian countries between 2000 and 2008. The significant increase in the number of floods is self-evident.

Number of flood and storm events in select South-East Asian countries in 2000 vs. 2008

Transport infrastructure faces two major types of climate related risks:
  • Long-term changes in the climate, particularly temperature and precipitation; and

  • “Shock events” such as flooding and landslides—which as shown above are occurring with increased frequency and intensity.
To address these challenges, countries need to adapt the way they operate, maintain, upgrade, and expand the many assets that make up a road network. Our new report, Integrating Climate Change into Road Asset Management, provides governments, road authorities, and development partners with practical guidance on how to navigate this process.

Long-term climate changes are less problematic for many assets such as pavements since their life cycle is relatively short, and certainly shorter than the time it takes for significant changes in temperature or precipitation to occur. The exception to this are bridges  and major drainage assets which have long service lives.

On the other hand, even the shorter lived road assets will likely face some extreme weather events within their life cycle. When designing road infrastructure, engineers normally account for such climate shocks, but work under the assumption that those will be rare and of limited magnitude. However, we are now seeing that infrastructure are being subjected to more frequent and extreme events within their design life. This leads to a shortening of the service life, and/or temporary loss of accessibility.

As part of the business-as-usual asset management practices within a road authority, there are a number of actions that can be taken to prepare for both long-term climate changes and increased shock events, including:
  • Identifying of key routes recognizing the many roads are also corridors for other essential infrastructure such as water, power etc.;

  • Defining what resilience means for different road categories and making residents and road users aware of how long they may be without transport access after events;

  • Agreeing in advance on how damage repairs from shock events will be funded and who will be entitled to financial support;

  • Having mechanisms in place to promptly respond to shock events when they do occur;

  • Developing models that predict the impacts of climate change events on the road network, including the collection of data to feed and calibrate these models;

  • Revising design guides to take into account the changing frequency of climatic events;

  • Retrofitting infrastructure that is found to be deficient; and

  • Trialling new materials that may better resist climate change.
The key is to: prepare in advance of the events; have in place mechanisms to respond during an event; after a major weather event, ensure we can “build back better” to make the network more resilient to future events. The actions are illustrated in the figure below.
View full flowchart

Now that we’ve laid out the fundamentals, what are the specific steps that are required to integrate climate change into the asset management process? The Intergovernmental Panel on Climate Change (IPCC) suggests that there are three broad strategies for adapting to climate change: protect, accommodate and retreat. Asset management addresses the first two strategies, and can influence decisions around when the third may be warranted.

The table below suggests actions across the full scope of asset management. Not all recommended actions will be applicable to all road authorities, although it is certainly advisable to at least consider each within the overall asset management improvement process.

One area that requires special attention is data collection. Better data and information assist in better decision making. Investing into the collection of relevant data and information is the first and foremost investment into climate adaptation.

For some highly vulnerable road networks, actions beyond those in the table may be necessary. In extreme cases, these steps may go as far as retreat, which is the abandonment of certain assets that cannot be reasonably protected from climate change. The IPCC particularly applied this concept in the context of coastal protection, but it can be generalized to all geographic locations.
View full table

Mobility is vital to the social and economic wellbeing of a country. It is critical that the resilience of transport infrastructure is enhanced in order to minimize the impacts from climate change. Formally integrating climate change considerations into an asset management program will provide the framework and mechanism to achieve this. This will help agencies with planning, protecting, and responding to the challenges of climate change.

Follow on work to consider how climate change risks should be incorporated into performance based contracts is currently under way with funding from PPIAF. This work is expected to be completed in late 2017.


Chris Bennett

Lead Transport Specialist

Theuns Henning

Senior Lecturer, University of Auckland, New Zealand

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