Climate Change in Georgian Bay – Part 1

Carling Thom Morrissey Photography

Since the Industrial Revolution, when we began burning coal and then oil, people have been changing the planet’s climate. According to NASA and the world’s scientists, burning fossil fuels and other human activities has increased the carbon dioxide (CO2) in the atmosphere from 280 parts per million to 400 parts per million in the last 150 years.

What does this mean? Our atmosphere has had to absorb more CO2 and other gases—and now we are seeing the effects. As these gases accumulate, more sunlight and heat are absorbed, increasing the overall global temperature and changing the climate that previous generations have known. We are responsible for raising the global temperature in just 50 years.

We have raised the global temperature “just” 2°C but that means arctic ice and glaciers melt, sea levels rise and floods occur, with more frequent and more extreme weather events here in Ontario. For example, last summer we saw Oastler Provincial Park area in Seguin Township hit with tornado-like winds. This phenomenon become more frequent – along with heavy precipitation and flooding. Next week, I’ll address some of the climate scenarios for the Parry Sound area based on the new Climate Atlas (

Unfortunately, global temperatures are warming faster every decade. Why? As global temperatures rise, polar ice melts, shrinking the white reflective area and expanding the dark surface area (of oceans, lakes and land) that absorbs the sun’s rays. Instead of a slow, progressive warming, these feedbacks accelerate warming faster each decade, with unpredictable weather patterns.

Catastrophic events, such as drought, food and water shortages, disease, refugee crises and war, are all likely scenarios if human activities continue at current rates of carbon emissions. Our grandchildren – in 2030 and in 2050 and beyond – will be the victims of our lifestyle and our consumption of unsustainable energy.

Also unfortunate is the ‘war on science’ that has been documented by Harvard University and others. Well-funded climate denial campaigns circulate in mainstream media – confusing the public about very simple facts: climate change is occurring right now; our current human activities are causing it; and we must act quickly to avoid catastrophic effects. In a review of over 52,000 independently-reviewed journal articles about climate science, 99.4% were consistent with these facts – making it not a “theory” as it was in the 1950s and 1960s – but an international scientific consensus.

Less Ice and Warmer Water in Georgian Bay

Sampling in Green Bay, Lake Michigan. February 2009.
Sampling in Green Bay, Lake Michigan. February 2009.

By looking at ice cover and water temperature data for Georgian Bay, we can see climate change happening in our region. The Canadian Ice Service has been recording water temperature and ice cover weekly since 1973. Similarly, weather stations, buoy monitoring and research labs combine data across the Great Lakes to measure the impacts of climate change.

You may live near a water body and also notice when the ice forms in the fall and melts in the spring—known as “ice on/off dates.” If ice on/off is recorded over decades, climate trends may be seen.

Notice that there is considerable variation in ice cover from year to year; this is common for most climate-related data. It is unpredictable year-to-year but shows long term trends of warming. Despite colder and warmer winter years, there is a clear long-term warming trend.

Results from summer surface-water temperatures show a similar warming trend to ice. Since 1970, the average water temperature in Lake Huron has increased at a rate of approximately 1°C per decade. A rise of 10°C in Lake Huron over this century is changing the ecosystem as we know it. This rate is even faster for some of the shallower Great Lakes.

The maximum annual ice coverage for Lake Huron, 1973 to 2016 (Canadian Ice Service). Bars indicate percentage of ice cover, and the sloped line represents (warming) downward trend for maximum ice cover over 43 years. Learn more at

David Bywater is the State of the Bay Project Manager for the Georgian Bay Biosphere Reserve, a not-for-profit dedicated to environmental and community well-being. He can be reached at [email protected].

[partner-profile name=”Muskoka Watershed Council” title=””]

The Muskoka Watershed Council created a unique report using the best available science to help predict the future climate of the Muskoka region. It examines the likely impacts of a mid-century climate on our lakes and waterways, forests, community infrastructure and way of life. These include precipitation and drought patterns, record-high summer temperatures, extreme weather events, water quality and stormwater management and other infrastructure-related issues. The report calls for prompt action by provincial agencies, district and municipal governments, local businesses, community groups and individual citizens.

While there will be a number of negative impacts on our environment and in our lives, we have sufficient scientific understanding of the causes and processes involved, plus the necessary skills to plan for, and implement, adaptive responses that will help us minimize and manage these impacts. With community-wide commitment to planning and timely action, we should be able to adapt effectively. Climate change is here, and we must act to manage the impacts responsibly.

Go to to learn more.


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