Rising sea levels and surges from intensifying storms pose a growing threat to the nation's roads, railways, harbors and airports, according to a new report from the National Research Council. The federally funded study calls on government and industry planners to start factoring climate change into transportation system design.

One hundred thousand kilometers of U.S. coastal highways are occasionally flooded. More severe weather could make these roads impassable, a major problem since many of them are also designated as public evacuation routes during natural disasters.

"The time is now for the transportation community to understand the implications of and address climate change as an important consideration in developing and maintaining the transportation that works in our country," says nationally recognized civil engineer Henry Schwartz, chairman of the National Research Council committee that wrote the report. He says the chaos caused by such transport bottlenecks would be costly in human and economic terms.

The report's authors support the findings of the United Nations Intergovernmental Panel on Climate Change, which conclude that global warming is real and caused by human activities.

The climate threats identified in the report include increases in very hot days and heat waves, higher Arctic temperatures, sea level rise, an increase in more intense precipitation and more severe hurricanes.

The U.S. transportation system was designed and built for local weather and climate conditions based on conventional climate models and forecasts. Schwartz says those predictions may be less reliable, especially in light of the weather and climate extremes in recent decades. "So we have to adjust. The one-in-100-year storm may become the one-in-50-year storm."

He says design adjustments must be made to the infrastructure to account for the changes.

Local managers already face day-to-day problems, such as the rising cost of transportation because of higher fuel prices and worsening traffic congestion.

Schwartz says they have paid little attention to the impact global warming may have on transportation. He suggests governmental agenices take inventory of their transportation infrastructure "to understand what assets are at risk."

Just such an inventory will be getting underway in the northeastern state of Massachusetts later this year according to Luisa Paiewonsky, commissioner of the Massachusetts Highway Department. "[We will be] inventorying our critical low-lying and coastal highway infrastructure to assess the vulnerability of it to events caused by climate."

The National Research Council report also calls for the creation of a clearinghouse to consolidate information on climate science and transportation, better communications among transport agencies and establishment of new engineering standards. Schwartz says local, state and federal governments and the private sector must work together to adapt.

Schwartz says taking actions to prepare for climate change now could help avoid costly future disruptions ? and even more costly repairs to the nation's vital transportation network.