Special Report 290 identifies five future climate changes relevant to transportation infrastructure and operations:
Increases in very hot days and heat waves,
Increases in Arctic temperatures,
Rising sea levels,
Increases in intense precipitation events, and
Increases in hurricane intensity.
The committee that prepared the report emphasized that, contrary to the general perception that climate change will result in gradual changes in temperature and sea level rise in coming decades, the key concerns for transportation are temporary, abrupt, and unanticipated extremes of temperature, precipitation, and storm intensity that could occur at any time and that will become more frequent.
The committee that prepared Special Report 290 concluded that the greatest climate change impact on North American infrastructure will likely be flooding of coastal roads, railways, transit systems, and runways because of global rising sea levels coupled with storm surges, exacerbated in some locations by land subsidence. Roughly half of the U.S. population resides in coastal counties; hence, a substantial share of the nation’s population and infrastructure is at risk. Among the challenges posed in responding to climate change are deep uncertainties about its impacts as well as about the effectiveness of various adaptations (Dewar and Wachs 2006).
For example, climate change will alter weather patterns so that historical records will no longer be reliable guides to 100- and 500-year floods. Such rare events are the basis of designing facilities to withstand maximum likely storms. They will become more frequent than history suggests, but climate scientists are unable to forecast where and when such changes will occur at the temporal and spatial scales that planners, designers, and operators of infrastructure require. The limited ability to predict the location and frequency of more intense storms will result in higher degrees of uncertainty with regard to severe outcomes than trans-