Physical characteristics
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Temperature
Rising temperatures can have enormous ripple effects on lake ecosystems, shorelines and more.
Hotter weather can affect overall water temperature, ice cover, the timing of seasonal mixing of lake waters, evaporation and precipitation.
As the air has been warming,
so has the temperature of Lake Huron.
Throughout 2021, the average surface temperature of Lake Huron was 10.13 °C, an increase of 1.21 °C over the long-term average of 8.92 °C. (measured from 1995-2020) [1]
How do we know how the air will affect the water?
One 2022 study used a sophisticated model that considers:
atmospheric temperature
3-dimensional dynamics
ice
cover
The study looked at two climate change scenarios:
less warming
(also known as RCP 4.5)
more warming
(also known as RCP 8.5)
They also looked at two different time periods: mid-century (2030-2049) and late century (2080-2099). [2]
In mid-century, the surface temperature of Lake Huron is predicted to rise by an average of
1-1.3 °C. By late century, it could be 1.8-3.9 °C warmer.
Slide to see the difference. Find out more about what each scenario means here.
Likewise, a 2021 study showed that the surface temperature on inland lakes in southern Ontario were likely to increase by between approximately 2-4 °C by 2050, with smaller lakes showing more potential for warming. [3]
The increases may sound small, but they can have big effects on the rest of the lake environment, including on the aquatic life within it.
You can view the temperature (and water currents and wind speed) of the Great Lakes in real time with Seagull, run by the Great Lakes Observing System.
Ice cover
The amount and duration of ice cover on a lake affects more than just whether it becomes a great place to play hockey or ice fish in the winter.
The presence of ice changes the way heat and moisture transfer between the air above the lake and the water within it. A lake with less ice cover has more water available to evaporate, which can lower the overall water level of the lake.
The amount of ice also affects how much sunlight penetrates into the water, which in turn can change the ecosystem of flora and fauna in the lake. For major bodies of water such as the Great Lakes, less ice cover can also have positive effects such as increasing the length of shipping season
for transporting goods.
Canadian and American scientific agencies have been making detailed observations of ice cover on the Great Lakes since 1973.
Between 1973 and 2018, ice cover on all Great Lakes has seen a general decrease, with Superior, Huron, and Erie losing ice cover more quickly than Ontario and Michigan. The number of days per winter with ice coverage has also declined since the start of the record in 1973 for all Great Lakes. [4]
EOSDIS Worldview (nasa.gov) (Feb 18, 2014)
EOSDIS Worldview (nasa.gov) (Feb 22, 2020)
In 2021, Lake Huron had 48.3% ice cover, compared to the long-term average of 64.6% (from 1973 -2020).
A 2022 study has shown that ice cover on Lake Huron may drop to between 9% and 20% by the end of the century, depending on overall atmospheric warming.
Reduced ice cover can also lead to more snowfall in areas along the shores of the lake, as the warm, unfrozen lake is more easily evaporated into clouds. Considering how much snow areas like Saugeen-Bruce already receive, this could mean much more shoveling in the winter!
Did you know?
Lake Huron and Lake Michigan are
joined together through the
Straits of Mackinac?
This eight-kilometre-wide stretch allows water to flow in both directions between the lakes, keeping their water levels in equilibrium. This means that Huron and Michigan are functionally one giant lake. Researchers often refer to it as Lake Michigan-Huron, especially when talking about the lake’s water levels.
The Straits of Mackinac are a crucial waterway for commercial shipping. The currents in the Straits are complex. Overall, water flows from Lake Michigan to Lake Huron. However, NOAA GLERL researchers have shown that about once every day and a half, winds cause the currents to change direction. The surface and deeper waters can also flow in opposite directions. These variable currents have repercussions on how various substances can be dispersed and transported within the Straits.
Water levels
Up or down, rise or fall—as the climate grows hotter, how would you expect lake levels to change?
Ontario’s climate is projected to get warmer and wetter. Will higher temperatures cause more evaporation, lowering the water levels of the lake? Or will increased precipitation cause lake levels to rise?
Both factors (and others, such as the amount of run-off that enters a lake from the surrounding land) are at play, which makes it a challenge to predict the future of
lake water levels.
Source: Tristan Schmurr
To figure out the future levels, researchers start by looking at past trends.
Water quality
H20, or H20hno?
Status of the Great Lakes 2022 Report
The Government of Canada and the U.S. Environmental Protection Agency released an overview of the status and trends of the Great Lakes ecosystem including nine indicators of ecosystem health.
Indicators related to the Great Lakes:
Drinking water
Beach water quality
Toxic chemicals
Groundwater
Nutrients & algae
Indicators were measured for each lake and assessed on a scale of good, fair, poor or undetermined. Trends were also assessed to determine whether indicators were improving, unchanging or deteriorating.
Approximately 60% of the population of Ontario gets their drinking water from the Great Lakes, and in 2020, 99.8% of municipal residential treated water met Ontario’s standards. The quality of treated drinking water from all the Great Lakes is ranked as “Good”, and based on Ontario data, that trend appears to be stable.
Climate change “is very likely to have significant negative effects on source water quality that will put great stress on drinking water infrastructure.”
The ELPC notes:
An increased number of intense rain events have the potential to increase levels of bacteria and nutrients like nitrogen and phosphorus from agricultural runoff, leading to an uptick in harmful algal blooms. [8][9]
Blooms that are dominated by cyanobacteria are particularly harmful, as they create additional toxins with a number of exposure mechanisms including ingestion through recreation, contaminated drinking water, or contaminated seafood and vegetables.
