More frequent heavy rainfalls in the western half of the state have increased the volume and velocity of water in rivers and streams, undermining the foundations of bridges. Rising sea levels are eroding coastal roads. In the drier eastern half of the state, more frequent wildfires have forced road maintenance crews to change their methods in an effort to prevent sparks that might cause a blaze.
"Each time you replace a bridge, states have to be thinking about not just what kind of traffic demand there is, but how do I make sure this is a bridge that will withstand the future given the erratic weather patterns and climate change we're seeing," Hammond said. "It's a new layer of analysis."
About half the states have taken some steps toward assessing their most critical vulnerabilities, experts said. But few have gone to the next step of making preparations. New York was an exception. Not only had transit officials made detailed assessments of the potential effects of climate change, but they'd started to put protections in place. Subway entrances and ventilation grates were raised in low-lying areas to reduce flooding, but that effort was overwhelmed by Sandy.
"They got hit with what was even worse than even their worst-case scenario," said Deron Lovaas, a transportation expert with the Natural Resources Defense Council, an environmental group. "This was an active test of ... climate preparedness, and they failed."
While more than 97 percent of the scientists who publish peer-reviewed research say that global warming is real and man-made, the issue remains highly charged. In conservative states, the term "climate change" is often associated with left-leaning politics.
Planning for weather extremes is hampered by reluctance among many officials to discuss anything labeled "climate change," Horsley said.
"In the Northeast, you can call it climate change. ... That's an acceptable term in that region of the country," he said. "Elsewhere, in the South and the (Mountain) West, it's still not an acceptable term because of ideology or whatever you want to call it."
For example, Horsley said, in North Dakota, where there has been severe flooding in recent years, state officials avoid bringing up global warming, preferring to couch their discussions on how to shore up infrastructure as flood preparation.
The Obama administration has also shied away from talking publicly about adaptation to climate change. Transportation Secretary Ray LaHood's office refused to allow any department officials to be interviewed by The Associated Press about the agency's efforts to help states adapt. The Transportation Department and other federal agencies are involved in preparing a national assessment of climate change impacts and adaptations that may be needed. Their report is expected to be finished in the next few months.
Steve Winkelman, director of transportation and adaptation programs at the Center for Clean Air Policy, said he uses terms like "hazard mitigation" and "emergency preparedness" rather than climate change when talking to state and local officials.
"This is about my basement flooding, not the polar bear — what I call inconvenient sewer overflow," Winkelman said. "It makes it real."
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American Association of State Highway and Transportation Officials http://www.transportation.org