Great Lakes: A climate haven?

A view of Toronto skyline with Lake Ontario on the front at night

Written by Abel

Abel is the founder of Esper’Ance In Action. He is a Sustainability & social impact practitioner for 12+ years. Value driven, Abel loves to build community, engage and solve complex problems with empathy and compassion.

January 6, 2023

Following the blizzard 2022, time to set some facts straight: I often hear that the Great Lakes region will not be affected by climate change and that we are lucky to be in this region. If it is true that the Great Lakes will fare somewhat better than other regions regarding climate change, they will certainly not be spared. 

As we are witnessing once again the power of lake effect and still counting the victims (60+ in total) of the latest “one in a generation” disastrous weather event, i.e. the 2022 blizzard, it is time for me to write about one of my biggest pet peeve.

When talking about climate change in Ontario, I am often served with a “meh, we’re lucky to be in the Great Lakes, we have so much water, good weather, soil, etc. Climate change won’t affect us much and if anything, everyone will want to immigrate here, that’s the main issue. We are fine, this region is a climate haven”.

I could just snap when I hear this.

  • First: gross! How is immigration an issue? I hope we are able to accept climate refugees and we should get prepared for that.
  • Second: wrong! The Great Lakes are not a climate haven and we won’t be fine.
  • Third: do you not see what is happening and how many disaster events we are seeing here?

So. Let’s break it down, shall we. Will the climate catastrophe spare the Great Lakes and can we just all return to drink a Caesar or is there a bit more to it?

I created an infographic to summarize all this, which is in image format below or downloadable in pdf here.


Scroll below the infographic to read the detailed explanation and article.

1.       What are the Great Lakes

The Great lakes are a series of five interconnected lakes (Superior, Michigan, Huron, Erie, Ontario) spreading along the Canada-USA border and connected to the Atlantic Ocean through the Saint Lawrence River. Their surface is as big as the United Kingdom.

They are the largest area of freshwater by surface on the earth and the second one by volume, containing 21% of the world’s surface freshwater (representing 5,439 cubic miles or 22,671 km3).

They formed around 14,000 years ago following the retreat of ice sheets and being filled up by melt waters.


2.       Importance of the Great Lakes

30 million people live in the Great Lake Region: approximately 30% of Canadians and 10% of Americans and more than 107 million in the extended region.

Economically, the region generates US$ 6 Trillion GDP and would be the third world economy if on its own, representing 30% of the US and Canada’s economy. The area is home to 51 million jobs.

The Great Lakes are known for their biodiversity, ecology, and fertile soils, representing 25% of Canada’s agriculture and 7% of US’s agriculture.

The region is also a massive connection and logistical hub with about 50% of the US / Canada trade happening in the area and with more than 200 million tons of cargo shipped annually.

Needless to say, this region is of massive importance for both the US and Canada and its popularity has kept growing over the years.


3.       The Great Lakes: a climate change haven?

At first, the Great Lakes seem like the perfect region to avoid climate change:

  • There is tons of water to keep life going even when temperature rise and drought happen
  • The Region sits 600 feet above sea level so there is no risk for it to disappear
  • Weather is pretty decent, in fact, a few degrees more wouldn’t hurt for these long winters
  • The area is super fertile and there is lots of possibility for agriculture

On paper, that all works. In reality though, this is a different story.


4.       Impact of Climate Change on the Great Lakes

The Great lakes are a fragile ecosystem whose balance is already being disturbed. There are a lot of studies showing that climate change is already happening and will have many impacts for the population living here and the ecosystems it hosts.


a.       General climate change impact:

Temperatures in the Great Lakes region are increasing, and this is accelerating in the last decade creating impacts for biodiversity, ecosystems and more;

Annual precipitations are also increasing, about 10% in the Great lakes between 1901 and 2015, compared to 4% overall in the USA. Not only precipitations have increased but intensity too with larger, wetter and longer events being observed, creating flood events and other catastrophes.

Extreme weather events are also increasing. In particular, lake effect snow activity has also increased in the snow belts around the Great Lakes, creating massive disruptions and disasters for inhabitants affected. Heat waves, cold days, are set to increase creating their lots of issues such as summer storms, wind events, etc.


b.       Impacts due to the warming of lake waters

Algae-blooms: Great lakes waters are getting warmer, especially in lake Huron with an increase of 5.2 F between 1968 and 2002 for its surface summer waters. Increase in water temperatures, air temperatures, combined with greater precipitations, longer agricultural seasons, lead to a higher risk of blue-green and toxic algae blooms in the lakes, affecting biodiversity, fisheries, habitats, drinkability and expanding the risk of invasive species.

Ice cover: in the 1970s, Great Lakes were on average 67% covered by ice in the winter, but this fell to 40% between 2003 and 2012. It is estimated that between 1973 and 2010, ice cover on the lakes declined on average by 71%, bringing its lot of issues. Combined with more storms, the lack of ice on the shores during winter increases the risk for erosion and flooding and could be harmful to the lakes’ ecosystems.

Destratification: lake levels are set to be impacted by climate change, although it is not clear at which scale (i.e. how much change). In addition, higher water temperatures impact another important event on the lakes, destratification. This event happens twice a year, in the spring and the fall, when surface waters reach 39 F, their higher density. In the fall, these waters will sink to the bottom and in the spring, the contrary happens.

Destratification is very important as it allows an exchange of oxygen from the top of the lake and nutrients from the bottom, triggering the aquatic growing season in the spring. Climate change projections indicate that these exchanges might happen earlier in the spring and later in the fall, disturbing the whole cycle and potentially leading to the decline of biodiversity populations in the lakes both at the surface and at depth.


c.       Impact on human activities

Agriculture might be a loser of these changes over the Great Lakes region. Wetter springs mean later planting and more extreme weather means loss of harvest. Hot temperatures might also affect yields and what can be grown in the area. It is not impossible to see corn and soy bean production move northward from the great lakes region in the future.

Other economic activities will be affected by these changes: power generation, dependent on lake levels, shipping, recreation, fisheries, infrastructures damages and pollution, shorelines activities and destruction, there is a lot at risk.


d.       Impact on biodiversity and ecosystems

As we know, ecosystems are fragile and a fine-tuned balance of evolution. With all the changes coming to the Great Lakes because of climate change, there might be disastrous effects coming. First, the risk to have invasive species flourishing in the lakes, from bacteria levels to bigger species, which could decimate native populations. Fish populations will also be affected, some moving north, some not being able to cope with changes and being replaced by other species. Wildlife in general will also be affected, having to move or being subject to new diseases, which could decimate populations. Furthermore, the change in climate will affect plant species growing in the region, changing food sources for animals. Contamination of lake waters will also affect negatively biodiversity in the area.


5.       So what?

In general, with climate change, a good rule of thumb is to never assume that any area will be spared. This goes for the Great Lakes as well. There are many studies showing the impacts climate change will have in the area and although some of the effects are still unknown or not well quantified, we cannot dismiss them.

At your scale, what you can do is to help with conservation efforts around the Great Lakes, call for more climate action and also fight against unbridled urban sprawl and poor urban planning. In Ontario, in particular, call the Provincial Government to not open the Greenbelt for development as it acts as our first defense against climate change and helps supporting the Great Lakes ecosystem.


Sources and to learn more about the effects of climate change on the Great Lakes:


The Nature Conservancy

The Great Lakes Region is not a climate refuge – Bloomberg article

Great Lakes Integrated Sciences and Assessments – NOAA team

Warmer, wetter, wilder: 38 million people in the Great Lakes region are threatened by climate change – The Conversation article

Lake Ontario water levels – the Narwhal article

US Resilience Toolkit – Great Lakes

Environment Protection Agency – Climate indicators – Great Lakes

Government Canada – State of the Great Lakes 2022 report

Great Lakes and St Lawrence Cities initiatives – Climate adaptation – climate impact

Council of the Great Lakes Region – Great Lakes economy infographics

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