A key assumption in planning is that weather and climate events may vary from year to year but climate remains stable over the long term and can be predicted on the basis of past return values. This assumption underpins most design standards, operations and maintenance programs, and planning for transportation projects and programs. However, climate change is altering the risk of many types of weather extremes, including the frequency, severity, or both, of high temperatures, heavy precipitation events, coastal flooding, and storms. This concept of non-stationarity (i.e., that future climate conditions and weather risks will differ from those in the past) challenges scientists and engineers to incorporate climate change into present-day planning when the future is manifestly uncertain. A general framework is presented for incorporating observed and projected future climate trends into infrastructure planning. The issues that remain to be resolved, including the challenges confronted in translating climate and weather-related extremes to information that is directly relevant to assessing potential impacts on infrastructure, are highlighted.
