Standing Senate Committee on Transport and Communications Impacts of climate change on transportation infrastructure in the Great Lakes and the St. Lawrence Seaway. February 27, 2024 Opening Statement by Robin Davidson-Arnott, Professor Emeritus, University of Guelph I will begin with a few remarks about who I am, my research background, expertise, and experience that is relevant to the Great Lakes. I will follow this with

summary points on key effects of climate change on factors that may affect shipping in the Great Lakes and St. Lawrence River. Finally, I will note some factors that act to limit the impact of climate change, and others not related to climate, but which need to be considered. I grew up in Trinidad (West Indies) and came to Canada in on a student visa to do an undergraduate degree in Physical Geography at the University of Toronto. I stayed on to complete a Ph.D. carrying out research on the dynamics of coastal sand bars in what is now Kouchibouguac National Park, NB.

Much of my work involved the use of SCUBA both for sampling and for the installation of instruments. I joined the Department of Geography at the University of Guelph in 1976, retired as Professor in 2009, and have continued to carry out research as an Emeritus Professor to the present. My research in the Great Lakes has focussed on field studies of coastal processes responsible for the erosion, transport and deposition of sediments on sandy beach and dune systems, as well as on the underwater erosion of cohesive bluff shorelines. I have worked on all the Canadian Great Lakes except for Lake Superior.

In there were record damages along the Canadian and US shorelines of the Great Lakes due to flooding and storm wave erosion associated with record high lake levels. Following this, I was appointed to the International Joint Commission (Canada/USA) Great Lakes Water Levels Reference Study Phase 1, 1987-89, as a Canadian Member of the Technical Working Group. I filled a similar role for the IJC Upper Great Lakes Reference Study, 2008-2011.

Also, in response to the effects of high lake levels and storms in 1985, I was seconded to the Ontario Ministry of Natural Resources full time in 1992-93 and part-time 1993- 1995 as one of members of the working group that developed the Ontario Shoreline Management Policy and the 900-page Technical Guidelines for its implementation by Conservation Authorities and the Ministry. I have continued working up to the present with CAs, government and non-government agencies, and with public groups on issues related to coastal processes and coastal management.

There has been considerable research into the effects of Global Warming on the climate of the Great Lakes region over the past two decades. There is general agreement that temperatures will continue to get warmer, that the increase will be greater than the average for global temperatures, and that winter temperatures will warm more than summer temperatures. It is expected that there will be an increase in the average intensity of Fall and Winter storms but there is much uncertainty as to whether the number of storms will increase.

Early predictions were that there would be a decrease in precipitation leading to a significant decrease in average lake levels. However, recent modelling predicts that increased evaporation will be offset by increased rainfall and that average lake levels will not change significantly. The most important effect of increasing winter temperatures for transportation is that the extent and duration of winter ice cover on the lakes and the St. Lawrence Seaway will continue to diminish. This can be seen already, for example, in the average number of days in the winter with >20% ice cover.

Between and this decreased from to in Lake Erie and from to in Lake Huron. This ongoing change has the potential to increase the duration of the shipping season both in the Fall and in the Spring. Ultimately it may allow for year-round shipping, as there are now many more years where the ice cover never exceeds 20%.

Potential increases in the severity of storms – giving rise to stronger winds and larger waves – are constrained by the restricted fetch lengths for wave generation in the lakes and the potential impacts on shipping are mitigated by the improvements in forecasting over the past 3-4 decades, thus providing the opportunity for ships to seek shelter when necessary. Responsibility for managing Great Lakes water levels and flows in the connecting channels is carried out by the International Joint Commission under binational treaties between the United States and Canada.

These treaties govern the operation of the two control structures in the system – the locks at Sault Ste. Marie and the dam at Cornwall and there and the protocols for their operation are well-established. There is some ability to control the timing and volume of flows so as to reduce both the peaks and lows in lakes Ontario and Superior, and to a lesser extent in Lake Michigan-Huron and Lake Erie.

While shipping is a major factor in the protocol for managing these two structures, the requirements of hydro-electric power generation, recreational boating, flooding of infrastructure, and the preservation of wetlands, are taken into consideration. In the event that decadal scale fluctuations in lake level exceed past extremes it is doubtful that the impact of this on shipping could be significantly mitigated through adjustments to the operation of the control structures.

Additionally, ongoing isostatic uplift of the outlets of Lake Superior, Lake Michigan- Huron and Lake Ontario continues to produce drowning of the US coast of Lake Superior (Duluth) and the south coast of Lake Michigan (Chicago) and to a lesser extent the west end of Lake Ontario. The communities along the lakeshore in these areas are highly sensitive to any manipulation of levels that increases the potential for flooding.

Communities on the north shore of Lake Superior (Thunder Bay) and of Georgian Bay (Collingwood, Parry Sound) are being uplifted, leading to reduced depth in navigating channels over time and these communities are highly sensitive to any manipulation that reduces the level in the lake. Finally, it is worth noting that both the IJC and the Ontario Government play important roles in managing the response to Climate Change in the Great Lakes and that the US plays a significant role in monitoring climate and climate change in the region.

A useful and readable reference on the potential impacts of Climate Change on the Great Lakes is: An Assessment of the Impacts of Climate Change on the Great Lakes by Scientists and Experts from Universities and Institutions in the Great Lakes Area. Report prepared for the Environmental Law and Policy Centre, University of Chicago, March 2019, 60 pp.