Projected changes in climate are expected to bring a range of challenges and benefits to Canada. Our economic and social well-being are greatly influenced by the health and sustainability of our natural resources, including water, forestry, fisheries and agriculture, and the reliability of our transportation and health care systems.

To date, the majority of impacts and adaptation research has focused on the biophysical impacts of climate change. Much of this research suggests that the most significant challenges would result from increases in the frequency and intensity of extreme climate events, such as floods, droughts and storms. Extreme events, as well as rapid climate change, can cause critical thresholds to be exceeded, often with severe or catastrophic consequences. In contrast, given appropriate adjustments, many systems should be able to cope with, and at times even benefit from, gradual temperature warming of limited magnitude. For example, in some regions, higher temperatures could enhance plant growth rates, decrease road maintenance costs and reduce deaths from extreme cold.

A recurring issue in the field of climate change impacts and adaptation is uncertainty. There is uncertainty in climate change projections (degree and rate of change in temperature, precipitation and other climate factors), imperfect understanding of how systems would respond, uncertainty concerning how people would adapt, and difficulties involved in predicting future changes in supply and demand. Given the complexity of these systems, uncertainty is unavoidable, and is especially pronounced at the local and regional levels where many adaptation decisions tend to be made. Nonetheless, there are ways to deal with uncertainty in a risk management context, and most experts agree that present uncertainties do not preclude our ability to initiate adaptation.

In all sectors, adaptation has the potential to reduce the magnitude of negative impacts and take advantage of possible benefits. Researchers recommend focusing on actions that enhance our capacity to adapt and improve our understanding of key vulnerabilities. These strategies work best when climate change is integrated into larger decision-making frameworks.

The following sections examine potential impacts of climate change and adaptation options for key sectors in Canada, as reflected in scientific papers and reports published since 1997. It must be emphasized that these sectors are both interrelated and interdependent, in that adaptation decisions undertaken within one sector could have significant implications for other sectors. It is therefore important to coordinate adaptation activities between sectors.