Pond hockey and ice skating have been a classic part of childhood for so many of us here in Canada. After all, one of the biggest upsides of an early-season cold snap is the rapid buildup of thick, human-bearing ice. But as the climate warms, what will this mean for the fate of the ice-coverage season? 

Ponds and lakes across Canada are experiencing shorter ice cover durations as a result of later freeze-over in the fall and earlier breakups and melting in the spring. For example, Lake Superior has lost more than 60 days of ice coverage since 1857. Thinning ice is a serious risk to human health and safety—particularly to children. Studies have shown that more people are dying from drowning as a result of unstable ice conditions and that children and youth are the most vulnerable. This problem is especially serious for Inuit communities in the North who frequently use snowmobiles to travel across the icy landscape making traditional hunting practices increasingly dangerous. Alongside these more serious consequences, reductions in ice cover threaten winter sports including ice fishing, skating, and more. This can prove to be economically and socially damaging to many communities. 

While the consequences of thinning ice on human communities are obvious, its effects on aquatic ecosystems are far less understood by the general public. Increasing air temperatures reduce the duration of ice cover on lakes and rivers which alters water quality, ecology, and biodiversity. Aquatic ecosystems rely on consistent seasonal heating and cooling patterns to regulate nutrient cycles and water mixing, as the stratification of the water temperature inverts between the warmer and colder months. Moreover, with a decrease in ice duration, the period in which photosynthesis can occur in the lakes and rivers extends longer into the fall season and starts sooner in the spring. This promotes an increase in microinvertebrate populations such as zooplankton and phytoplankton which has implications for other creatures in the water column. In some cases, it may increase the risk of toxic or damaging algal blooms, decreasing light penetration into the water which decreases photosynthesis in aquatic plant species and therefore causing hypoxic (lack of oxygen) conditions which can harm and even cause death of aquatic animals like fish.  

Harmful algal bloom in Lake Erie. Photo by European Space Agency (ESA). https://www.noaa.gov/media-release/noaa-partners-predict-large-summer-harmful-algal-bloom-for-western-lake-erie 

Another example of another harmful algal bloom in New Brunswick. https://globalnews.ca/news/9020375/new-brunswick-blue-green-algae-high-temperatures-rain/

Ice reductions are the obvious result of a warming climate. Climate change can be an incredibly overwhelming topic and it can be hard to stay optimistic. If you want to help make a difference, urge local, provincial, and federal governments to take bold, ambitious climate action— after all, Canada is the only G7 nation whose emissions have increased since the Paris Agreement was signed. Support Indigenous-led climate action. Support public transportation initiatives and divestment. Easiest of all, start a conversation (people often trust loved ones more than faceless scientists and dense academic journals)! 

To be entered in our giveaway, post a winter sports picture (ice skating, pond hockey, ice fishing, etc), tag us and use #25watershedmoments.  

CBC News. (2021). Northern lakes losing ice coverage due to climate change, finds study | CBC News. CBC. https://www.cbc.ca/news/canada/sudbury/northern-lakes-ice-coverage-climate-change-1.6221787 

Lake Erie Foundation. (2023). Algae. Lake Erie Foundation.  https://lakeeriefoundation.org/issues/nutrientsharmful-algae/ 

National Oceanic and Atmospheric Administration. (2019). NOAA, partners predict large summer harmful algal bloom for western Lake Erie | https://www.noaa.gov/media-release/noaa-partners-predict-large-summer-harmful-algal-bloom-for-western-lake-erie 

US EPA, O. (2016). Climate Change Indicators: Lake Ice [Reports and Assessments]. https://www.epa.gov/climate-indicators/climate-change-indicators-lake-ice 

Walsh, M. (2021). Canada’s emissions record worst in the G7, federal Environment Commissioner says. The Globe and Mail. https://www.theglobeandmail.com/politics/article-contradictory-spending-slow-pace-trouble-trudeau-governments-emissions/