Extreme events

Climate change can influence a variety of factors in coastal areas, including sea level, waves, and storm surge. Sea level rise increases the frequency and intensity of coastal flooding, and the impact of extreme events.

Storms, flooding and extreme weather can also cause erosion and associated sediment transport. As sea ice decreases and large areas of ice-free water develop, winter storms will have more significant impacts on coastlines. These changes can impact coastal ecology and infrastructure, and also affect marine transportation and the need for dredging.

Climate change is likely to result in more extreme events in the future. Accurately assessing vulnerability to climate change is an important step to develop management plans and actions for reducing the impacts. You can access our completed research projects related to climate change, rising sea levels and declining sea ice.

Storms

Large waves and storm surges can cause water levels to rise well above high tide levels. In Canada, storm surges can reach heights of 1 m or more on all three coasts.

Research completed to date indicates that the storm tracks in Atlantic Canada will move slightly to the north as a result of climate change. This is a result of expected changes in the Northern Hemisphere Jet Stream.

Observations show increased extreme storminess on a global scale. The most significant impact of future storms will likely be in areas of Canada where winter sea ice decreases. This is because sea ice reduces the energy in ocean waves and provides protection for coastlines.

Wave damage

Ocean waves can be a significant factor in determining the impact of extreme events. Wave size and the length of the wave season in the Arctic have increased since 1970. They are very likely to continue to get larger this century because there is less sea ice. Canada's east coast will also likely experience larger waves in areas where there is currently sea ice in the winter. This is because sea ice dampens the wave energy before it can impact the coastline and associated infrastructure. Off the Pacific coast of Canada, wave heights have been observed to increase in the winter and decrease in the summer, and these trends are projected to continue into the future.

Sea level rise

Sea level rise increases the frequency and intensity of coastal flooding, and the impact of storms on coastal ecosystems and infrastructure.

Global sea level will continue to rise throughout this century as a result of climate change. The amount of this increase will depend on future greenhouse gas emissions.

Since sea level changes will differ across Canada, accurately assessing local vulnerability to climate change is an important step in addressing the issue.

The differences around Canada are primarily as a result of the Earth's crust moving upward or downward in response to changes since the last ice age (about 10,000 years ago). This process is called Glacial Isostatic Adjustment.

Along most of the Atlantic and Pacific coasts and the Beaufort coast in the Arctic, local sea level rise is greater than the global average because land is sinking. In contrast, local sea level in the eastern Arctic and Hudson Bay is projected to fall this century because upward land movement will be greater than global sea level rise.

Our scientists have created an Canadian Extreme Water Level Adaptation Tool (CAN-EWLAT). It provides information on future water level extremes to assess vulnerability and guide actions to help reduce climate change impacts.

Related links

• Canada's Changing Climate Report – Changes in Oceans Surrounding Canada
• Relative Sea-Level Change (Canadian Centre for Climate Services)