Climate change will have many environmental, public health and socioeconomic impacts. In Quebec, these impacts will differ depending on the particular sensitivities of each region. The extent and costs of climate change impacts will likely increase over time. Key findings include the following:
The extent and magnitude of climate change impacts depend largely on changes in demographic, socioeconomic and environmental conditions. Apart from climate change per se, an analysis of anticipated impacts must also include an analysis of the factors that will affect the vulnerability of each subregion. Accordingly, the following points should be considered:
- From 1960 to 2003, temperatures in southern Quebec increased by between 0.5°C and 1.2°C in the southwestern and south-central areas, and by less than 0.5°C in the southeastern part. In northern Quebec, a gradual cooling has been replaced by a sudden warming of about 2 °C since 1993.
- Despite uncertainties, the use of increasingly high-performance climate models makes it possible to produce detailed climate scenarios for several parameters and several regions, all of which point to major changes in climate trends.
- In Quebec, there is a slowing of population growth and an increasingly aging population, except among First Nations and Inuit communities. There has been a population shift from urban centres mainly to the outer edges of developed areas and suburban belts in southern Quebec, resulting in urban sprawl onto high-potential agricultural land.
- Although the general state of public health is improving, the future trend is uncertain due to several factors, including the fact that high-risk populations are becoming increasingly vulnerable.
- Quebec's growing economy is now based primarily on the tertiary (service) sector and is largely integrated into the North American and world economies. In contrast, infrastructure is aging and is largely exposed to the vagaries of the weather. In addition, many communities outside large urban centres are dependent on natural resources and are therefore also highly vulnerable to the vagaries of the weather.
The largest climate changes in absolute terms are anticipated to occur in the northern subregion. They will exacerbate the problems already being experienced in this region with respect to communities' high level of exposure to natural disasters and their dependence on critical infrastructure, access to resources and traditional ways of life that are closely related to the existing natural environment. Terrestrial and aquatic ecosystems have begun to change, specifically in terms of their structure, due to permafrost degradation, the formation of thermokarst lakes and ponds, the expansion of shrub communities and wildlife population displacements.
Climate change will result in alterations to the natural environment with potentially significant implicationsin areas where natural resource development is central to the economy. The landscape, hydrology and geomorphology of streams, the distribution of plant and animal life, and regional biodiversity could all undergo significant changes, particularly in areas already subject to a high level of human pressure. In contrast, this could have a certain beneficial effect, due to an anticipated increase in productivity in certain sectors, such as hydroelectricity and forestry. Nevertheless, these scenarios remain tinged with uncertainty for several reasons: lack of data, conflicting historical trends, poorly understood processes, uncertainties related to the tools used, and North American market effects.
In the maritime subregion, where the coast is highly exposed to the hydrosphere, there will likely be increased shoreline erosion along the Gulf of St. Lawrence and the St. Lawrence River estuary, the area where most of the subregion's socioeconomic activity is currently concentrated. The combination of sea-level rise, the gradual disappearance of surface ice, the geology of certain coastlines and possibly changing storm patterns all appear to result in an increase in the natural process of erosion, causing adverse effects on the built environment, tourist attractions and the quality of life for many communities in this subregion, which depends heavily on waterways for access.
In the south subregion, an increase in the frequency, intensity or duration of extreme weather events is believed to pose increased risks for the aging built environment, vulnerable populations and communities living in areas exposed to natural hazards. Historical meteorological events have shown the high degree of dependency of urban and rural communities on water, energy supply and transportation infrastructure, all of which are exposed to the vagaries of the weather. Milder winters and hotter, more humid summers would lead to increased evaporation of natural waters; this could exacerbate water-use conflicts and lead to further degradation and loss of wetlands that rely on flooding. Climate change also poses significant risks to a number of threatened species already subject to various other stresses; these species have a low migration capacity and their habitat has become degraded. However, in this subregion, climate change could also result in energy savings (reduced demand) and development opportunities (increased plant productivity), resulting in annual gains of several hundred million dollars.
Adaptation to climate change offers many possible solutions to significantly reduce its adverse impacts. Human societies have always demonstrated an ability to adapt to climate variability and seem once again capable of overcoming the obstacles to climate change adaptation, which is based on the following elements: identifying and understanding the priority issues; collecting and disseminating information and data needed by the stakeholders involved in climate change adaptation; developing and applying the optimal techniques and technologies; amending or adapting policies, standards and organizational structures; and considering emerging uncertainties when making decisions. Quebec has a high degree of adaptive capacity, due specifically to its increasingly diversified knowledge economy. As for the natural environment, it adapts spontaneously and autonomously, and human systems may be able to assist with its adaptation. Although adaptation appears to be increasingly inevitable, little is generally known about its costs and limitations, particularly in the long term. Climate change adaptation measures should therefore be accompanied by reductions in greenhouse gas emissions in order to tackle the source of the problem and to minimize the 'nasty' surprises that the weather may hold in store for the future.