Our water
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The Great Lakes
The Great Lakes play a vital role in the social and economic well being of Ontario. Climate affects both the quantity and quality of water in the Great Lakes. At the same time, the Great Lakes have a significant influence on Ontario's climate. As a result of their influence, instead of having a climate similar to that of the Prairies, Ontario's climate has less extremes in temperatures and greater precipitation.
As the climate changes so too does the balance of these elements
What the models tell us...
GCM results suggest that by 2050, lake levels will be lower than they are now and perhaps by more than one metre. Models also suggest a smaller and earlier spring runoff. This could have a significant impact on fisheries and existing biological systems.
A lesson from the past
The Great Lakes
Because of their sensitivity to climate, the Great Lakes have not always looked the way they do now. Scientists have recently found evidence of submerged beaches that suggest the water level in the lakes (represented by the yellow lines) was below the level of their outlets (represented by the red lines) due to warmer and drier conditions about 7500 years ago. For reference, the current shorelines are shown in white.
Macy's Bay on Georgian Bay, May 15, 2000
Low water levels like these are likely to happen more often and for longer periods.
Did you know?
The Great Lakes system is the largest system of fresh, surface water on Earth. Only 1% of the Great Lakes volume is renewed on an annual basis. In other words, using more than 1% of the volume in a year will reduce the lake levels beyond natural renewal.
Who will be affected?
Hydro power: Lower levels and flows will result in less hydro power production.
Shipping: Lower water levels will increase shipping costs as ships will have to make more trips with light loads.
Shoreline properties: Over the short-term, lower levels will result in less flooding and erosion damage to shoreline properties.
Recreational boating: Lower water levels create problems for launching, hauling out, or operating boats in shallow areas.
Environment: Low lake levels for extended periods could have negative impacts on fish access to wetlands and other critical habitats.
Water supply: Lower levels can affect the ability of intakes to draw water. Higher wter temperatures create a more favourable environment for microbes and algal blooms, reducing water quality.
Did you know?The Great Lakes region is home to 25% of Canada's population, 45% of Canada's industries and provides the foundation for $150 billion in annual Canada/U.S. trade.
Inland lakes, rivers, and streams
Water is an intricate and vital part of the climate system. Water is also critical to every aspect of our lives including our health, energy production, industry, and transportation. Change the air temperature and the rate of evaporation and precipitation changes, altering the balance of the entire system and everything that depends on it.
As the climate gets warmer and drier, demand for water used for irrigation of farms and watering household lawns and gardens will increase. This, combined with greater levels of evaporation, will reduce the amount of water in streams and lower the water table, leaving less and warmer water for us to use. Warmer water may be great for swimming, but will likely lead to problems with water quality - microbes and algal blooms like warmer water too.
The hydrological cycle
Did you know?
Canada's per capita water use is the second highest in the world. In 1996, households in Ontario used 270 litres of water per person per day.
Water use in the home
References
Government of Canada and U.S. Environmental Protection Agency, 1995: The Great Lakes: an environment atlas and resource book; Environment Canada.
Smith, J.V. , Lavender, B., Auld, H., Broadhurst, D., and Bullock, T., 1998: Adapting to climate variability and change in Ontario; in Volume IV of the Canada Country Study: Climate Impacts and Adaptation; Environment Canada, 117 p.
Turner, R.J.W. and Clague, J.J., 1999: Temperature rising: climate change in southwestern British Columbia; Geological Survey of Canada, Miscellaneous Report 67.