Introduction - Ontario

The social, economic, environmental and cultural health of Ontario has been shaped largely by the region's geography, its natural resources and its climate. Although most activities in the province are relatively well adapted to current climate conditions, extreme climate events can bring about considerable damage. Climate warming is, and will continue to be, manifested in changes to both average and extreme climate conditions in Ontario. Such recent climate events as drought, flooding, heat waves and warmer winters have resulted in a wide range of impacts in Ontario, including water shortages, forest fires, lower Great Lakes water levels, declines in agricultural production, power outages and outbreaks of water-borne diseases. These impacts have had substantial economic and social costs, raising questions about Ontario's vulnerability to future climate change. The impacts of greatest current concern, both at present and in the future, differ within the various subregions of the province.

The degree to which Ontario will be affected by climate change is strongly influenced by its adaptive capacity. The most commonly used indicators of adaptive capacity are: economic resources; availability of, and access to, technology, information and skills; and the degree of preparedness of its infrastructure and institutions (Smit et al., 2001; see Chapter 2). Based on these factors alone, it can be inferred that the potential for Ontario to adapt effectively to climate change is high. Whether that potential is realized will depend on individuals, industry, communities, institutions and government incorporating climate change, along with all other important factors, into their decision-making. However, there are significant differences in adaptive capacity between all subregions and sectors. It also is possible that some changes in climate may occur too rapidly for ecosystems, social systems and industry to adapt effectively. Unless adaptation planning decisions are well informed by an improved understanding of both current vulnerabilities and the magnitude and timing of future change, the potential exists for insufficient action or for maladaptation (actions that inadvertently increase vulnerability to climate change).

This chapter presents an assessment of the most significant issues expected in Ontario as a result of climate change. The chapter is presented in four sections. Following this ‘Introduction', Section 2 provides an overview of key current and future environmental, demographic and economic conditions that influence vulnerability to climate change. Section 3 presents what is known about climate sensitivities, impacts and adaptive capacity for three subregions of the province (Figure 1; described below), highlighting the risks and, where information is available, the opportunities presented by changing climate. Section 4 presents a synthesis of results across subregions, identifying potential areas of greatest concern. The discussion addresses the social, economic and environmental risks that residents of Ontario are facing from climate change impacts at the regional, sectoral and community scales. It also presents analysis of factors that could exacerbate vulnerability to future climate change, the role of institutions in enhancing adaptive capacity, and discusses the need to mainstream adaptation to climate change into long-term planning processes. Case studies are used to illustrate different aspects of managing climate risks.

Much of the literature published since the last national assessment, the Canada Country Study (see Chapter 1; Smith et al., 1998) has identified in the Canada Country Study remain, most notably for some sectors (e.g. mining), subregions (e.g. the north subregion), communities (e.g. First Nations communities) and extreme events (e.g. insured and uninsured costs). The overwhelming majority of research is focused on potential negative impacts of climate change. As a result, positive impacts (benefits) may not be well understood. Clearly, just as adaptation will be needed to minimize negative impacts, so too will adaptation be required to capitalize effectively on any opportunities climate change may bring to Ontario.

For the purposes of this assessment, Ontario has been divided into three subregions, based on physiographic, social and economic characteristics (Figure 1, Box 1). This structure is used to highlight the fact that both key impacts of concern and the capacity to adapt to those impacts differ among the three subregions of the province, and likely require adaptation measures tailored to each subregion's circumstances.

The south subregion extends from the southernmost tip of Canada eastward to the border with Quebec. It is bounded to the south and west by lakes Huron, Erie and Ontario, and the St. Lawrence River, and to the north by the Precambrian Shield of the central subregion. The south subregion is the most densely populated area in Canada, and contains eight of Canada's sixteen most populous metropolitan areas, including its largest city, Toronto. The topography ranges from extremely flat in the southwest and southeast to the rugged Niagara Escarpment, with much of the natural landscape having been modified for urban development, transportation networks and agriculture. Although the Great Lakes border both the south and central subregions, they are treated in this chapter as a single system and part of the south subregion.

The central subregion encompasses more than half of the province and is dominated by forested terrain underlain by the mineral-rich Precambrian Shield. It includes a number of medium-sized cities, such as Sudbury and Thunder Bay, but is characterized by huge areas with low population densities. Resource-based communities, dependent on forestry, mining and tourism, are located primarily along major transportation corridors. The vast majority of forestry- and mining-reliant communities in Ontario are located in this subregion. The central subregion contains two-thirds of Ontario's provincial highway system that, along with rail lines, provides critical transportation linkages between eastern and western Canada.

BOX 1

The north subregion extends from the northern boundary of the central subregion to the coasts of Hudson and James bays. It is sparsely populated, primarily by small Aboriginal communities affiliated with the Nishnawbe-Aski First Nation. Continuous and discontinuous permafrost is found throughout the more northerly areas of this subregion. Much of the landscape is low lying and poorly drained, providing critical habitat for migratory bird species. The subregion is highly dependent on more than 3000 km of winter roads to provide supplies to numerous remote communities for which air transport is the only means of yearround access.