How Lake Ontario is at Risk from Climate Change: Essential Lessons from the Little Ice Age for Our Future Adaptation

Lake Ontario has always been significant to people living nearby. For ages, it has supported the local economy by providing resources for trade, food, and industry. However, with climate change on the rise, our relationship with this Great Lake is changing.

In my book, The Lives of Lake Ontario: An Environmental History, I explore how climate shifts have affected our use of the lake over time. For instance, during the Little Ice Age (from the 14th to the 19th century), both Indigenous peoples and settlers had to adjust to the colder environment around Lake Ontario.

Today, as we confront similar climate challenges, we can learn from how people adapted in the past. These lessons remind us of the importance of changing our interactions with Lake Ontario.

Before the Little Ice Age began, various Indigenous groups, including the Haudenosaunee and the Anishinaabeg, lived harmoniously with Lake Ontario. They hunted, gathered, and traded resources and were in tune with the climate, tailoring their farming methods to the changing seasons.

However, the Little Ice Age brought chilling temperatures, lowering average heat by about 1-2°C. This shift caused unpredictable seasons, making it harder for communities to rely on crops. Summers were sometimes marked by drought, while heavy winter snowfall disrupted hunting. These changes contributed to a decline in Indigenous populations in the region.

The climate also influenced the fur trade, as European demand increased due to changes in animal pelts and local resources. The cooler climate affected military strategies too. For instance, during the War of 1812, American warships faced disasters due to sudden weather changes, making it clear that respect for the environment was crucial for success.

While the climate presented challenges, it also opened new doors. It encouraged settlers to diversify their agriculture by introducing hardier wheat varieties and altering land use to create more farmland. Surprisingly, thicker ice on Lake Ontario even made winter transportation easier, allowing for new ways to traverse the landscape.

As winter temperatures eased in the 19th century, more settlers moved to the Lake Ontario basin, influenced by the milder climate. This migration changed the local economy and culture significantly.

Over the years, the relationship between Lake Ontario and the local population has evolved dramatically. The region’s growth, especially in Toronto, relied heavily on the lake’s resources.

But this development has come with costs. In the 19th century, excessive deforestation and pollution began to harm the lake. The 20th century saw an increase in these negative impacts, including urban sprawl, invasive species, and chemical runoff. Today, Lake Ontario struggles with pollution, harming its ecosystems and water quality.

The ongoing strain from climate change adds to these problems, making it harder for the lake to recover from our past actions.

Climate change is also altering water levels dramatically. Recently recorded high levels have led to shoreline erosion, threatening homes, infrastructure, and essential services like septic systems and power plants.

Despite these challenges, Lake Ontario has shown remarkable resilience, but it’s under significant pressure. Now is the time to adapt our practices and improve our relationship with the lake. While the Little Ice Age taught people to adapt to cooler conditions, we need to find ways to cope with our warmer climate today.

To protect Lake Ontario, we must stop harmful practices that contribute to pollution and climate change. This means rethinking how we use resources, shifting our economic systems, and reducing our reliance on fossil fuels.