Scientists estimate that lake levels will drop dramatically – perhaps as much as 3 feet by the 2050s.1 Climate change impacts pose formidable challenges to the entire Great Lakes shipping industry, which regularly operates with minimal clearances. Shallow near-shore areas, including harbours and connecting rivers, will experience some of the most noticeable changes in depth and flow. For vessels operating on the Great Lakes and St. Lawrence River, the impact of lower lake levels on these critical areas will include restrictions in vessel draft and tonnages carried, forcing more frequent trips. This could raise transportation costs by as much as 22 per cent.2 Given this scenario, the entire industry has a pressing incentive to begin planning for change: its own survival.
Currently, the only options to adapt to lower water levels are to reduce cargo loads or to increase publicly-subsidized dredging. The first option may be economically unsustainable; the second, environmentally so.
There is a silver lining for the industry. The comparatively smaller carbon footprint of shipping relative to rail or truck gives this mode of transport a real advantage in the fight to slow climate change, but only if the industry can eliminate the environmental impacts addressed in this document. Adapting to climate change provides an opportunity to redefine an outdated industrial model in a way that aligns industry operations with restoration of the Great Lakes and St. Lawrence River.
- Develop environmentally friendly strategies to adapt to natural fluctuations and future water level scenarios. Options to explore include rerouting international cargo to deeper ports, and shifting the fleet of domestic vessels to shallow draft.
- Examine impacts of maintaining the authorized dredging depth under different water level scenarios, including the likelihood of wetland loss, excessive channelization, or accelerated water loss.
1 Great Lakes St. Lawrence Seaway Study. Transport Canada et al. /GLSLS%20finalreport%20Fall%202007.pdf> . Fall 2007.
2 "Global Climate Change and Great Lakes International Shipping" Dr. Frank Millerd, Wilfrid Laurier University, National Academy of Sciences Transportation Research Board Special Report 291, May 2007.