Overview

"Climate Adaptation" has been defined as, "Actions by individuals or systems to avoid, withstand, or take advantage of current and projected climate changes and impacts. Adaptation decreases a system's vulnerability, or increases its resilience to impacts."

Adaptation contrasts with the other main climate change emphasis area - greenhouse gas mitigation - which entails reducing greenhouse gas emissions in order to reduce, or "mitigate," the impact of climate change.

Among climate scientists, there is overwhelming evidence and consensus that climate change is already occurring and that it will intensify in coming decades, even if significant steps are taken to reduce GHG emissions. Current and future climate impacts include higher temperatures, rising sea levels, more severe storms, increased precipitation in some areas and decreased precipitation in other areas, higher risk of drought and wildfires in the West, stress on ecosystems, acidification of the ocean, damage to coral reefs, impacts on agriculture, and greater risk of flooding. While the most obvious risks are to coastal areas, there are also significant climate risks and changes for inland areas.

In 2008, the Transportation Research Board of the National Academy of Sciences reviewed the evidence on climate change and issued Special Report 290, "Potential Impact of Climate Change on U.S. Transportation," with the following key findings and conclusions:

• Climate change will affect every mode of transportation and every region in the United States, and the challenges to infrastructure providers will be new and often unfamiliar.
• State and local governments and private infrastructure providers will need to incorporate adjustments for climate change into long-term capital improvement plans, facility designs, maintenance practices, operations, and emergency response plans.
• Design standards will need to be re-evaluated and new standards developed as progress is made in understanding future climate conditions and the options for addressing them.
• Transportation planners will need to consider climate change and its effects on infrastructure investments. Planning timeframes may need to extend beyond the next 20 or 30 years.
• Institutional arrangements for transportation planning and operations will need to be changed to incorporate cross-jurisdictional and regional cooperation.

For state DOTs, adaptation planning is in the early stages, with much more research and work to be done. Many state and federal agencies are conducting research on climate change to identify local and regional vulnerabilities in facilities and systems, ascertain risks, and prioritize adaptation efforts. Some state DOTs are engaged in adaptation planning, and others are planning to focus on adaptation needs, including the need for design changes, retrofit of vulnerable facilities, revision of drainage systems, and revisiting emergency evacuation planning.

It is likely that the understanding of climate risks and risk-based adaptation planning will evolve significantly over time. For those seeking a better understanding of climate adaptation for the transportation sector, the 2008 TRB Special Report 290, Potential Impact of Climate Change on U.S. Transportation is an excellent starting point.

This section of the AASHTO Transportation and Climate Change Resource Center website provides links to a wide range of international, national, regional, and state reports and resources on climate adaptation for transportation.