Possible locations for adaptation to climate change by Canadian commercial navigation on the Great Lakes

Climate change is expected to bring about lower water levels and reduced depths in the Great Lakes, with consequent reductions in vessel cargo capacities and increases in shipping costs. Under the most severe conditions annual transportation costs for Great Lakes - St. Lawrence River commercial navigation could increase by 29 percent,- more moderate climate change could result in a 13 percent increase, based on current prices. The impacts vary between commodities and routes. Cost increases of this magnitude suggest that adaptation measures may be worthwhile. The most obvious form of adaptation, and likely the least expensive, is deepening or increasing water depths at harbours and other shallow water points. Depth improvements should be carried out where benefits are highest. A small number of ports and shallow water points are responsible for most of the cost increases. A method of determining the most beneficial depth improvements is proposed.