No matter what it is called, climate change, climate chaos, global warming, or greenhouse effect, the dramatic warming of the earth represents a long term risk to State Departments of Transportation (DOTs). Many transportation professionals feel that this risk is non-existent or insignificant, since it is gradual and the effects are subtle and random. The two significant snow storms in Washington D.C. in the winter of 2009-2010 demonstrate the chaotic and episodic nature to our climate. These events had a significant impact on the momentum of climate change management in the US from a political and public point of view.

Regardless of the politics and industrial lobbying, significant scientific evidence has demonstrated that climate/chaos, regardless if it is due to natural or anthropogenic sources, is real and the long term impacts need to be managed for future generations.  If certain types of biological and chemical thresholds are exceeded, there is no time for mitigation and recovery within the human timeframe.

It is important to note that there has been more emphasis on how to reduce greenhouse gas emissions and less focus on how to manage and adapt to climate chaos.  Even if greenhouse gas emissions were eliminated or stabilized today, the effects of global climate change/chaos would still be experienced for the next 50 years and beyond.

Transportation systems are at some risk within the United States including Colorado and the Intermountain West.  In the long term, climate chaos impacts have a probability of impacting the levels of service, safety and the integrity of the transportation system infrastructures. Existing highway system design criteria that are based upon current climate patterns and statistical data will become outdated and ineffective. This system ineffectiveness could lead to: 1) structural failure 2) safety risk to the traveling public, and 3) significant impact to the environment.

The long term cost to maintain transportation system integrity and level of service could be significant, if potential climate chaos impacts are ignored; therefore, an understanding of the potential impacts, mitigation and an identification of vulnerable areas within State DOTs is critical in order to effectively manage climate chaos risk.

As an example, high intensity storms may become more intense and frequent within Colorado, thus making highway drainage design criteria out-dated; 50 year storm events may now be  10 year storm events due to the higher intensity and episodic nature of storm events. Existing highway drainage capabilities may become ineffective over time and thus pose a safety hazard to the traveling public caused by hydroplaning or colliding with deep standing water in below grade structural areas (below bridges).

Intermountain West Perspective

Climate chaos impacts realized in the Intermountain west will be based upon numerous variables such as geographical location, land form characteristics, wind patterns, elevation, and distance from tropical disturbances.  Intermountain states like Colorado, are not likely to directly experience climate chaos impacts associated with the increase in Arctic temperatures, rising sea levels and increase in hurricane intensity; however, there is a probability that western states will be impacted by increases in hot days and heat waves, and increases in intense precipitation storm events. These weather impacts will eventually have an impact on the transportation systems.

It is very possible that the design criteria that has been used in past will not be applicable to the new climatic conditions of the next 50 years and beyond.  There will be some existing transportation infrastructure that may be at risk and may require retrofitting or monitoring to ensure that the level of service, structural integrity and environmental safety is protected and maintained.  

To address these risk management issues, direct and indirect climate chaos impacts that have a probability of impacting highway infrastructure should be defined and better understood.  Direct impacts are those felt directly from physical climate chaos factors such as temperature, wind, snow and rainfall events.  Indirect impacts are more environmental and behavioral in nature such as biological responses to climate chaos that may influence transportation patterns, habits or safety. The infestation of bark beetle has killed millions of trees in Colorado due to stressors aggravated by climate chaos.  These trees represent a significant risk to the regional transportation system and residents. Wildfire conditions may occur in heavily infested areas where residents and wildlife are unable to safely evacuate the area and landslides may be experienced due to vegetative cover loss.

The following are some examples of potential climate chaos impacts that need to be better understood by Intermountain West DOTs:

High Temperatures

• Pavement buckling
• Increased traffic congestion due to vehicle overheating
• Pavement rutting due to surface softening
• Wildfire evacuations
• Temporary loss of the movement of goods and services from wildfires

Precipitation Extremes

• Increased rain accumulation and drainage
• Undersized drainage systems
• Undersized water quality structural controls
• Increased erosion from construction sites
• Increased road closures from high snowfall events-need for traveling public shelters
• Proximity to stream systems during intense storm events
• High risk watersheds
• Road and bridge wash outs and failures
• Increased accidents due to increased standing water in low areas
• Temporary loss of the movement of goods and services from flooding or structure failure
• Change in floodplain delineations that may impact bridge integrity
• Increased usage of traction sand and/or deicing chemicals from high intensity snowfall events

To maintain the level of service to Intermountain West DOTs’ transportation systems and maintain the public safety, Intermountain states need to investigate the long term risk associated with potential climate chaos.  In order to manage the climate chaos risk, DOTs should identify and understand probable impacts that may occur in the next 50 years and beyond until greenhouse gas emissions stabilize. The following are the DOT benefits gained from this type of risk management study:

• Provide DOT management an awareness and understanding of potential climate chaos impacts and the need to develop risk assessment strategies.
• Maintain safety to the driving public by identifying high risk infrastructure problems and improving evacuation routes and shelters for wildfire and extreme weather events.
• Anticipate significant long term costs and risks by identifying suspect design criteria that may become ineffective due to parameter changes.
• Anticipate additional costs associated with new highway design criteria, retrofits and highway maintenance activities due to weather extremes.
• Save financial resources by identifying and preventing infrastructure failure for highways adjacent to streams and bridges within high risk watersheds and within new floodplain delineations.
• Save maintenance costs by identifying highway materials that are more sustainable under extreme weather conditions.
• Increase public relations and education on climate chaos impacts to the transportation system; the DOT will be seen as a proactive leader that is looking ahead in managing public safety and managing future financial risks.