This weekend's tragic rail disaster in Lac Megantic, Quebec should serve as a reminder that there is no completely safe method of transporting oil, gas and other volatile substances. There are just magnitudes of risk. Canada and, especially, the U.S., need to curb carbon emissions and step away from their addiction to fossil fuels. But will blocking new pipelines in the U.S. or across Canada lead to a faster end to this addiction? Or will it simply lead to the substitution of rail transport -- by most measures relatively safe, but statistically not as safe as pipelines? These are valid questions on both sides of the border and ones brought into sharp focus by Lac Megantic.