Climate Change Impacts

Global warming, and the resulting climate change and extreme weather now appearing worldwide, is arguably the biggest and most challenging threat to the Great Lakes.

(Here is GBF's Commitment To You On Climate Change. This 2 page document was approved in June 2019 and added in September 2019)

The impacts do appear to be alarming. Economically, commercial navigation, recreational boating, recreational fishing, property values and hydropower have already experienced financial impacts due to unnatural extremes in water levels. Beyond our economic interest, scientists agree that there will be ongoing negative impacts from climate change for the health of ecosystems, biodiversity, and water quality.

Climate change can be tackled. Collaboratively, we all worked to reduce The Ozone Hole with scientists, governments, industry and the public. Acid rain was significantly decreased in the 1990s. We need to stop taking a wait and see approach, really fight cynicism, and look towards building climate resiliency and adaptive management for the issues we're already starting to experience, and work collectively to keep global warming from getting worse in the centuries ahead.

18 of the 19 hottest years ever recorded have occurred since the year 2001, including 2019.

Based on the General Circulation Model, climatologists have determined that the climate of the Great Lakes basin will increase by 2 to 4 degrees Celsius over the next 50 or so years. For more information on Global Circulation Models, go to this link.

With this warming trend comes a variety of other effects: warmer water and air temperatures, earlier and wetter springs, drier summers, later falls, and changing snow3. Over-all, there will be more severe weather events - more intense rainfalls over shorter periods of time, more protracted drought-like conditions, flashier storms with stronger wind gusts, longer ice-free periods on the lakes but more ice storms, and more evaporation.

World Temperature

The International Joint Commission (IJC) in its November 2017 newsletter noted these changes that are already occurring in the Great Lakes' climate:

  • "An increase in air temperature by 2 degrees F since 1900, particularly warmer nights; warmer winters with a 71 percent drop in Great Lakes ice coverage since 1973; and nine fewer days with frost since 1958, and resulting warmer water temperatures.
  • An 11 percent increase in precipitation since 1900, 37 percent increase in more extreme precipitation events since 1958, more extreme swings between drought and drench, and increased variability in lake levels
  • Changes in the distribution and vitality of cold-climate-dependent aquatic and terrestrial species."
  • That’s why we believe it is important to support ongoing research and science to help understand these impacts and work towards mitigation solutions that help the ecosystem and economy. But that only treats the symptoms. Our work is also focused on educating the public with a balanced view of the available science.

    Updates and summary of climate change effects

    From 2020: For a short overview of climate change effects and impacts in Georgian Bay, please watch this 13 minute video presented by GBF's Executive Director David Sweetnam.

    For futher studey: Interesting reference materials and updates from GBF in 2018:

  • If you want a great overview of impacts that are happening in the world, in Canada, In Ontario, in the Great Lakes, and Georgian Bay, please watch a 30 minute presentation by Dr. Carto, from the Office of the Environmental Commissioner of Ontario, who presented at Georgian Bay Forever's H2O October 2018 conference. Make sure you have WIFI. Click here to go to the 30 minute video, highly rated by attendees to the day conference.
  • Winter article:Impacts of Climate Change. Winter Tourism & Recreation in Ontario. This article was written for the Winter 2018 GBF newsletter issue by the Ontario Centre for Climate Change Impacts and Adaptation Resources, and is very relevant for Georgian Bay. Read the 2 page article at this link.
  • Impacts to water levels – increasing variability, more extremes

    There are different climate models, and these get updated as conditions change.

    The conclusions range. Even with much more to learn, there are two key takeaways, best expressed by research scientists Dr. Drew Gronewold and Dr. Richard Rood, “as researchers specializing in hydrology and climate science, we believe:

    1. Rapid transitions between extreme high and low water levels in the Great Lakes represent the ‘new normal’.
    2. And, more importantly that, “past conditions around the Great Lakes are not a reliable basis for decision-making that will carry into the future.”

    Warmer air temperatures affect lake levels by changing the nature and timing of precipitation and runoff (more intense rainfalls), decreasing ice coverage (71% decline over the past 40 years reported by NOAA) and increasingly changing the predictability of evaporation patterns from the lake surface.

    Understanding weather and climate. NOAA describes it this way: “Weather is what you might see outside on any given day, while climate is the average of that weather over a longer time period. Climate is what you expect, weather is what you get."5 Each year does not represent the climate, which is measured over decades. Below, you will note some specific examples of evaporation in a given year and the variability, but understand that many researchers conclude that evaporation levels will increase and will outpace any increases in precipitation in the long-term.

    Examples: Evaporation on the Great Lakes

    Cool winter, little ice

    For the Great Lakes, as huge bodies of open water, with Lake Michigan-Huron being the largest among them in terms of surface area, changes have serious consequences. As noted, ice cover on the Great Lakes during winter has been trending downward over the long-term, with a decline of over 70% over the past 40 years. A full third of the water Georgian Bay can be lost in the winter due to evaporation. When cold prevailing winds sweep from the north or northwest over the warmer water surface , they pick up a lot of moisture, only to drop it again as lake effect snow when they hit land on the other shore or beyond the watershed. This situation helped create some of the prolonged low annual water levels, some unprecedented, we experienced from about 2000 to 2013.

    We are in transition between old and new environmental stasis conditions.

    Cool winter, lots of ice

    In 2014, El Nino, changes in the Jet Stream and a southward shift of the North Polar vortex led to record low temperatures and high ice coverage. In the beginning of the year, an Arctic cold front including what some referred to as a nor'easter travelled across Canada and the United States, resulting in heavy snowfall.

    Little ice

    Warm winter, warm water and low ice

    In the last few winters (2015 and 2016) we've seen warmer winters combined with warmer water. This leads to little or no evaporation. Weather is weather, and in such years there simply isn't as much water loss in those years.

    For more scientific explanation about these last two conditions, please visit this page "Water levels, evaporation, ice coverage and thermodynamics"

    Climate and weather - a puzzling relationship.

    It's like doing a puzzle without a picture where the pieces can alter and change the puzzle as it progresses over time. It is clear that climate change is effecting weather patterns, but each weather event is a puzzle piece, not the whole puzzle.

    In general, water levels are driven by a variety of factors. Some are short term and some are long term. As noted earlier, NOAA describes it this way: “Weather is what you might see outside on any given day, while climate is the average of that weather over a longer time period. Climate is what you expect, weather is what you get."5

    For more information, please visit:

    The takeaway. We can't just pay attention to the weather.

    Remember, many researchers conclude that evaporation levels will increase and will outpace any increases in precipitation in the long-term. This means that Georgian Bay water levels will continue decline over the long term due to changes in the climate, while climate change driven weather will continue to become flashier in the short term and there will be increasing variability.

    Water Levels

    In its 2012 Upper Great Lakes study, the International Joint Commission determined that there are three main drivers impacting long term water levels in Georgian Bay and Lake Michigan-Huron: (1) climate changes; (2) previous dredging and unexpected erosion in the St. Clair River; and (3) glacial isostatic rebound. While all have contributed, it is currently climate change that was determined to be the main and ongoing driver of long term water levels declines, and extreme variability.

    At the same time, the economic consequences to property, infrastructure and ecosystems aren’t slowing down. New thinking, new policies, and new structures that build in climate resilience are needed! Even the investor community is starting to recognize this need that the insurance industry surely understands as illustrated in this article, “Extreme Weather is the New Normal”.

    There are solutions, but we need to act!

    To mitigate extreme water levels for the short term (the next 100 years), Georgian Bay Forever has been working with AECOM, a world renowned engineering firm, and successfully bringing attention to Increasing climate resilience including using adaptive structures for water levels to decision makers. Read more about climate resilient structural solutions in this report summary link.

    Each of us has a responsibility... at the same time, to help reduce carbon emissions to reach the goal of limiting global warming to 2 degrees Celsius, and prepare for weather extremes. These solutions must become ingrained – the goal can’t be done without making changes in our lives.

    Here are some links to things that you can do to reduce the impacts of severe weather events and increased global warming:

    Climate change impacts more than water levels. The effects of climate change will continue to wreak havoc on the water levels of the Great Lakes and Georgian Bay. Doing nothing is too expensive! (See Low Water Blues Summary Report) . We need to pursue short-term mitigation measures for the next 100 years, while simultaneously working as individuals in tandem with all levels of government to ensure that global warming does not exceed 2 degrees Celsius. Because you care about water, please read on about climate change impacts to water quality, habitats and biodiversity.

    Impact to biodiversity and habitats – ecosystems

    Scientists estimate that climate change could lead to the loss of up to 30% to 60% habitat for cold water fish6, and wetland losses in certain areas already stressed by loss of habitat.

    Ecosystems are able to respond to a variety of stressors until they reach a tipping point and Georgian Bay Forever has been working for a number of years to understand the science surrounding this issue.

    There have been measurable trends in surface water temperatures increases of about 1°C per decade since the 1970s. Even minor temperature changes can have an impact on ecosystems, and that’s one reason why we are working with the University of Guelph to build a library of all aquatic species using DNA barcoding, so that they can be monitored, and results and impacts brought to appropriate decisions makers. More info on this project, at at this link.

    We’re concerned we are not doing this fast enough, and we appreciate all donations from supporters of Georgian Bay to help us build this conservation tool. For an example of how climate change impacts one species of fish, Lake Trout, read this article from Fishery Biologist John M. Plumb,PhD, from the United States Geological Survey from our Summer 2017 newsletter. Click here for the article .

    Impacts to wetlands: important habitat

    We also know from our work with NASA, that when water levels decline over a prolonged period of time, wetlands are impacted - particularly in the southeast part of Georgian Bay. That area is more populated, and wetlands have already been reduced due to development pressures. Further declines because of extreme lows driven by climate change, create even greater risk to fish populations that depend on wetlands as nurseries and places to forage for food. For more information, explore these links:

    Phragmites shows how climate change can further help invasive species

    Climate change creates better conditions for many invasive species that already reduce biodiversity and outcompete native species. One example is the invasive plant Phragmites. Non-native Phragmites are advancing into Georgian Bay from the South and taking hold in wetlands and developing into monocultures that outcompete native plants. They grow so densely that they do not provide good habitat for native creatures.

    Stop Phrag

    Phragmites will do well in the extreme water levels that exceed historical fluctuations that have been brought on by climate change. This plant thrives in exposed lakebeds due to low water in Georgian Bay, but also adapts well to fluctuating and higher water levels. Phragmites has developed an ability to both trap air on its roots surface and to pump air into its hollow rhizomes to allow it to survive extended submersion during high water or flooding periods. In Georgian Bay this means that Phragmites has been observed growing in 6 to 9 feet of water. With no natural predators, great spreading capability, poisoning its neighbours, and an ability to survive and thrive in the face of the newer climate impacts, Phragmites continue to pose great risk to the biodiversity in the wetlands we have left and the animals that depend on them.

    Furthermore, warm water improves habitat for an invasive that produce another toxin – botulinum toxin - that then kills our diving birds and native fish like Lake Sturgeon.

    Wetlands help mitigate climate change impacts

    Ultimately, the wetlands themselves are critical to mitigating some of the impacts of climate changes and their degradation and loss needs to be avoided. For more information on supporting Georgian Bay Forever’s efforts to rid our coastlines of this highly destructive invasive, please visit this link .

    Man made climate change is changing the habitat and environment for our native species very quickly, and it threatens so many of them. We need to all work together on quick and effective monitoring of these ecosystems as the impacts of climate change continue, so these results can be brought to decision-makers and policies enacted to protect against the more severe disruptions of the biodiversity of species in Georgian Bay.

    Effects on the water we drink and swim in, and on the living space of our aquatic animals

    The safeguards that we designed and built into storm water and sewage infrastructure to prevent pollution into our waterways decades ago, are simply not equipped to deal with the more extreme conditions brought on by climate change.

    Waste and Stormwater Overflows

    Our future promises flashier storms with shorter bursts of greater precipitation.

    Precipitation factors

    There has been 37 percent increase in more extreme precipitation events since 19587 . Wastewater and stormwater infrastructure designed and built 30 to 100 or more years ago did not predict this new unpredictability, or in some cases warnings were ignored. We are starting to feel the impacts.

    We noted with concern this headline in the Midland Mirror in the summer of 2017 “Excessive rain causing Midland to dump raw sewage into Georgian Bay”. The article mentions that over 1.3 million litres of raw sewage has ended up in Georgian Bay from the Town of Midland in the past four years. 8. Clearly, we don’t want to be swimming in sewage. To get a further sense, read the is 2 page article " Water Quality Issue: Sewage Overflows Into Georgian Bay" by Sara Carter, a member of our Communications Committee team.

    The Town of Midland is hardly alone - in fact, the Great Lakes Commission noted at the end of September that US Great Lakes states would need $271 billion to improve public water systems.9 As for Ontario, GBF has written this letter in support for Bill 141, which aims to make public all sewage overflows. While it has not been tabled by the current legislature, we feel public disclosure is important for Ontarians to truly understand the scale of this issue and the work needed to confront it. We would like to hear from you in this 2 minute survey as GBF works towards further action.

    Algal blooms

    Another impact on water quality from climate change is increasing risk of more algal blooms. While some algal blooms are natural and have been observed historically, there are places in Lake Erie that are experiencing greater outbreaks, some of which are toxic. Microcystin is a neurotoxin sometimes produced by blooms of freshwater algae. 10 In the summer of 2014, 500,000 people in the city of Toledo were left without drinking water because of toxins in their drinking water from a toxic algal bloom in Lake Erie. Large intense rainfalls produce a lot of untreated run off containing nutrients like phosphorus from fertilizers used agricultural lands and other pollution from hardened cityscapes the flows into our Lakes. Phosphorus entering the lake helps algal blooms to grow.

    It's bad for us, and it's bad for many species.

    Warm water reduces the cool water fishes environmental quality and improves habitats for invasive species which we talked about in the impact to ecosystem segment. Not only, are these impacts terrible, but reduction in water quality from stormwater run-offs and sewer overflows are clearly more hazardous to the aquatic creatures that have to live in the resulting pollution. Please see this article and video from Ecowatch; which shows a salmon struggling for life in a polluted stormwater run-off.


    Wetlands, that filter and purify water, are degraded by invasive species, lost due to extreme low water levels, and overwhelmed by extreme weather events. These impacts combined with increasing development, remove a significant ally in fighting water quality degrading climate changes. Wetlands help provide a natural buffer to reduce flooding and erosion that can occur, and they also act as an effective water filter helping to control and absorb excessive nutrients that can otherwise become pollutants. Critically, they act as important carbon sinks helping to absorb increasing carbon in the atmosphere. Research shows that freshwater wetlands are even more important for regional carbon sequestration than tidal saltwater wetlands.11 Protecting wetlands from invasive species like Phragmites and excessive human development, while simultaneously working to mitigate the adverse impacts to wetlands from climate change will be crucial to reducing the over-all harms brought on by global warming.

    Watch this 16 minute video for suggestions on how you can adapt your property to the new realities. Presented by GBF’s Executive Director David Sweetnam.

    We would also very much welcome any suggestions, or experiences you have had with making adaptation changes to your property. Please email

    There are solutions.

    The causes of climate change are big social issues and the impacts of climate change are life threatening. Such big problems can make us feel powerless. We aren’t. We can’t ignore the risks and the continued evidence and hope that it goes away. It won’t. Climate change impacts are already being felt and we need to mitigate their impacts. Let’s take heed from Albert Einstein’s, “ Three Rules of Work: Out of clutter find simplicity. From discord find harmony. In the middle of difficulty lies opportunity.”

    And remember - we've done it before. Collaboratively, we all worked to reduce The Ozone Hole with scientists, governments, industry and the public. Acid rain was significantly decreased in the 1990s.

    Here is what you can do:

    a) Support mega climate resilient solutions and infrastructure in Georgian Bay and places you care about. By donating to Georgian Bay Forever, you are supporting the adoption of climate resilient structural solutions for adaptively managing extreme water levels.

    b) Make your properties more climate resilient, and decrease your contribution to global warming. AS noted above, in 2020, GBFs Executive Director presented some ideas for your property. See this 16 minute video by clicking here. There are a number of initiatives below that you can undertake and more that you can find on your own. Here are a few examples: drive cars that are electric or a hybrid, put more native plants in your landscaping, naturalize shorelines of properties instead of planting green grass down to the water, don’t throw “flushable” baby wipes down the toilet – they absorb fats and block sewage pipes and cause raw sewage overflows (More info ) , encourage your local municipality to move away from so much impermeable concrete and create more permeable surfaces and retention infrastructure, work to remove one-time use/ throw away items (especially plastics, straws for example) from your lifestyle, and consider reducing the importance of purchasing more and more inanimate stuff in your life.

    c) Volunteer in projects that protect the natural world. We spend so much of our time taking what nature provides for us and quite a bit of energy in denying the adverse consequences of those choices. By working to restore nature ecosystems, like volunteering for a Phragmites cut to protect water filtering wetlands or removing plastic litter from shorelines to reduce absorption of toxins into the food web as examples - the rebalance of connection with nature begins to be restored. You’ll also be happier for it!

    Ideas from GBF's David Sweetnam. 16 minute video originally presented in summer 2020
    Click here to get the video.

    Eat for human and planetary health

    (Update Jan 2019). Donna Mitchell writes a blog post: choosing to eat more plants and less meat, and to waste less food, is one of the most effective ways to reduce your carbon footprint while also improving personal health.
    Click here to read the article.

    Last updated: December 2017


    1The Weather Network

    2 National Aeronautics and Space Administration (NASA), National Oceanic and Atmospheric Administration (NOAA) and a number of other foreign research centres
    3GLISA. "Snow in the Great Lakes: Past and Future". Retrieved December 2017.
    4Quinn, F. and B.M. Lofgren. 2000. "The Influence of Potential Greenhouse Warming on Great Lakes Hydrology, Water Levels, and Water Management."
    5National Oceanic and Atmospheric Administration, “What is the difference between weather and climate?” [] December 7, 2015.
    6Some of the more recent materials we are looking at include the EPA's Climate Change and Risks Analysis Report(2).This report places US number at 61% loss of cold water fish habitat (without mitigation). The 28% GBF reported based on coastal wetland inventory changes modelled in is well within those bounds. The World Wildlife Fund currently is reporting between 45 and 30% of habitat loss for cold water fish (retrieved Feb 2016).
    7From IJC newsletter Nov 15, 2017 “IJC Presents Findings for Climate Change, Crude Oil Transport, Water Quantity and Quality at Healing Our Waters Conference”. From the IJC Great Lakes Water Quality Board summary of findings.
    8Mendler, Andrew. Excessive rain causing Midland to dump raw sewage into Georgian Bay. Midland Mirror. Retrieved Sept 27th, 2017 at
    9Leaders: $271B Needed for Creaky Great Lakes Water Systems. AP, US.News. Best States. Sept. 21, 2017. Retrieved at
    Nahlik, A.M. and FEnnessy M.S. "Carbon storage in US Wetlands." December 2016. Retrieved in October 2017.

    Other references:
    • From IJC newsletter Nov 15, 2017 “IJC Presents Findings for Climate Change, Crude Oil Transport, Water Quantity and Quality at Healing Our Waters Conference”. From the IJC Great Lakes Water Quality Board summary of findings.
    • Moudrak, Natlia." Extreme Weather is the New Normal". Oct.5, 2017. Retrieved December 2017.
    • Salmon struggling. Retrieved December 2017.
    • The Associated Press. "U.K. engineers launch ‘sewer war’ against giant fat blob" Sept 12, 1017. Retrieved December 2017
  • Dr. Drew Gronewold, Associate Professor of Environment and Sustainability, University of Michigan, Dr. Richard B. Rood, Professor of Climate and Space Sciences and Engineering, University of Michigan.
  • Note - We try to bring together information to help understand this topic. We do use sources to provide information and visuals. We do our best to attribute properly and try very hard to get it right. If we have made an inadvertent mistake around recognizing someone’s work or misinterpreting the work, please contact us and we will correct.