Climate change in Ontario



Climate-related impacts on water resources, energy, agriculture and natural ecosystems could have profound implications for human health and for the economy of Ontario. Questions remain about whether enough is being done to put in place adaptation measures to blunt some of the worst and unavoidable impacts of climate change in Canada’s most populace province.

This fourth article in the GLOBE-Net series on the Natural Resources Canada report From Impacts to Adaptation: Canada in a Changing Climate, examines the impacts of climate change on Ontario.

The opening paragraphs of 'Go Green: Ontario’s Action Plan on Climate Change' states that the plan includes some of the most comprehensive, forward-looking steps on the environment that Ontario has ever contemplated.

The Plan focus largely on what has been done to make Ontario green and what must be done to reduce greenhouse gas emissions, because 'Faced with the challenge of climate change, the only way to have a strong economy is to go green. And the only way to go green is to have a strong economy.'

There is the inference throughout the Plan that if we do reduce greenhouse gas emissions and do all the many fine and desirable things to be more energy efficient, more responsible in about generating or recycling wastes, and more innovative in developing clean technologies to drive our industrial processes, etc., that the impacts climate change will be lessened or will go away.

Nothing could be further from the truth. Climate change is not going to go away and reducing greenhouse gas emissions - assuming that Ontario or any other province could actually achieve significant cuts in this regard - will not stem the inevitable impacts that will affect our forests, water systems, weather or air quality.

This does not suggest that the initiatives put forward in the Five Points of the Go Green Plan (Green Targets, MoveOntario 2020, Creating Jobs by Going Green, Green Power and Grow Green) are bad ideas or a waste of time. Indeed they are vitally important and should be pursued. What is at issue is whether these measures are enough in terms of adaptive strategies to prepare us for what is inevitable in terms of climate change impacts.

The Natural Resources Canada report From Impacts to Adaptation: Canada in a Changing Climate does not make for easy reading. But the implications of its findings are of profound importance to Ontario. These are some of the key points:

Water Systems Impacts

  • Ontario’s average annual temperature, which has risen by 1.4°C over the last 60 years, will continue to rise and the impacts of this increase which are already affecting the province’s freshwater systems will only get worse.
  • Ice cover on the Great Lakes has been shortened by up to two months, which has contributed to major ecosystem changes including extensive algae blooms and invasions of non-native species. Decreased summer precipitation and increased evaporation in the winter from reduced ice cover have caused a decrease in water levels in the Great Lakes, which in turn has impacted on Ontario’s shipping industry.
  • Most vessels using the Great Lakes-St. Lawrence River system are designed specifically for the seaway, and are operated to take advantage of maximum water depths in connecting channels and ports. Their usable capacity diminishes with decreased water levels; each 2.5 cm loss in water level translates into between 100 and 270 tonnes of lost carrying capacity. Projected increases in shipping costs to compensate for such losses could range from 8% to 29% by 2050.
  • Water level changes in the Great Lakes will also impact on hydroelectricity generation in Ontario. Water level changes have reduced hydroelectricity output by up to 26% at some stations, requiring the acquisition of additional supplies of electricity from other domestic or US sources during peak demand periods. In recent years, rising water temperatures in the Great Lakes have also impacted electricity generation from nuclear and coal-fired plants by reducing the efficiency of their cooling systems, and forcing cutbacks in energy production.

Extreme Weather

  • Increased frequency of extreme weather events has the potential to disrupt critical infrastructure in Ontario as well as the health of its residents. More frequent and intense rainfall events will increase the risks of summer floods, with implications for large urban drainage systems. In recent years, flooding associated with severe weather has disrupted transportation and communication lines, with damage costs exceeding $500 million.
  • These precipitation events have had an impact on public health as well, such as the May 2000 event that contributed to the E. coli outbreak in Walkerton, Ontario, which killed 7 people and made 2300 ill.
  • Extreme winter weather events such as ice storms, which occur in milder winters, have disrupted power transmission for months at a time in the province. During summer heat waves, precipitation is expected to be significantly reduced when the demand for water is the highest. Summer water shortages already have been documented in southern regions of the province and will become more frequent as summer temperatures and evaporation rates rise.
  • The annual average number of ‘hot days’ (1961-2000) with temperatures of 30°C or above was 8 each in Toronto and Ottawa and 15 in Windsor. These numbers are likely to triple in Windsor by 2050 and nearly quadruple in Toronto and Ottawa by the 2080s.
  • Extreme heat events will put additional stress on Ontario’s already stressed energy supply. Ontario’s installed generation capacity is approximately 30,000 megawatts and climate change is expected to increase peak demand beyond this level in the coming years.

Air Quality

  • Higher temperatures will also affect air quality in Ontario, significantly increasing photochemical smog formation. Ontario has reported statistically significant increases in the seasonal means for smog from 1980 to 2005. The Ontario Medical Association estimates that the annual illness costs of air pollution in Ontario include 5 800 premature deaths, more than 16 000 hospital admissions, almost 60,000 emergency room visits and 29 million minor illness days.
  • The number of premature deaths is expected to rise to about 7 500 by 2015, and may exceed 10,000 by 2026. The total number of minor illness days is projected to increase to more than 38 million annually by 2026.


  • Climate change is expected to produce conditions that encourage agricultural pests and diseases, which could negatively impact crop production and lead to substantial economic losses. Changing climate patterns will also alter the geographic distribution of plant diseases and the survival of pathogens. Increased heat stress will result in lower weight gains in beef cattle, lower milk production in dairy cattle, and substantial losses in poultry production.
  • Water supplies for livestock may be contaminated by run-off in watersheds where heavy rainfalls flush bacteria and parasites into water systems. In extreme drought conditions, the potential for water to become toxic from sulphur and Cyanobacteria (blue-green algae) creates serious problems for cattle production.
  • Increased frequency of forest fires and outbreaks of forest pests will adversely impact the health and economic base of communities dependent on the forest industry, particularly in the far northern parts of Ontario’s boreal forest.

Adapting to Climate Change

Ontario’s potential to adapt effectively to climate change is high. Whether that potential is realized will depend on whether individuals, industries, communities, academic institutions and government agencies adequately take climate change into their long-term decision-making.

Ontario’s climate change plan is in large measure an emissions reduction plan, and does not address fully the massive adjustments that will be needed in all of Ontario’s key industrial sectors to deal with the inevitable climate changes that are coming. Nor does it provide a comprehensive framework to mobilize the resources of all government to start this process.

Ontario needs a Climate Change Adaptation Plan that deals with all the impacts noted above in the Natural Resources Canada Climate Change Report.

The Ontario government pledged to create an Expert Panel on Adaptation to assess the vulnerability of Ontario to the effects of climate change and to make recommendations to address these threats. The panel is to include members from a range of sectors and communities - environmental non-government organizations and experts in the field of climate change adaptation, engineers and health specialists, as well as representatives of Ontario’s First Nations and northern communities.

We would urge the Government of Ontario to move quickly to mobilize this panel, because relative to the enormity of the impacts that climate change will have upon the economic, social and physical well being of Ontario, much, much more must be done to prepare adequate adaptation strategies and programs.

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