Significant impacts on U.S. transportation planning are forecast in a new report about to be released by the Transportation Research Board, an arm of the National Academies of Science. TRB Special Report 290: Potential Impacts of Climate Change on U.S. Transportation concedes that "Little consensus exists among transportation professionals that climate change is occurring or warrants action now." But the report identifies "plausible future scenarios" which represent "significant challenges for transportation professionals." The committee "finds compelling scientific evidence that climate change is occurring, and that it will trigger new, extreme weather events."Special Report 290 identifies "five climate changes of particular importance to transportation and estimatedsthe probability of their occurrence during the twenty-first century." Included, as #4, is "Increases in intense precipitation events. It is highly likely (greater than 90 percent probability of occurrence) that intense precipitation events will continue to become more frequent in widespread areas of the United States." Louisiana being America's largest salt-producing state, the salt industry will be particularly interested in the report's prediction of increased coastal flooding, particularly of the Gulf coast and drier conditions in the upper Midwest "resulting in lower water levels and reduced capactiy to ship agricultural and other bulk commodities." Among the adaptive operational responses, the first example identified is "Snow and ice control accounts for about 40 percent of annual highway operating budgets in the northern U.S. states" and "operational responses are likely to become more routine and proactive than today's approach of treating severe weather on an ad hoc emergency basis." Roadway designers are encouraged to recognize the likelihood of more freeze-thaw cycles. In this, of course, snowfighting professionals are already well advanced in their "adaptation." The committee speculates that there will be "benefits for safety and reduced interruptions if frozen precipitation shifts to rainfall."

Canadian discussions and studies are more advanced than in the U.S. and also predict impacts on use of road salt for winter maintenance. In "Climate Change and Ontarios's Winter Roads: Trends and Impacts on Ontario Winter Road Maintainence Ops" and "Climate Change Impacts and Adaptation: A Canadian Perspective," experts agreed that salt usage in southern and western Ontario would be unchanged by global warming, but that salt usage would increase in northern and eastern parts of the province.