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Extreme events

The most significant impact of future storms will likely be in areas of Canada where winter sea ice decreases. Copyright: Shutterstock.

The most significant impact of future storms will likely be in areas of Canada where winter sea ice decreases. © Shutterstock.

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

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 in mitigating these impacts. Our scientists have created an adaptation planning tool for coastal infrastructure related to future water level extremes. We also have completed research projects related to climate change, rising sea levels and declining sea ice.

Flooding

Global average sea level will continue to rise throughout this century. Future changes in relative sea level along Canada’s coastline will vary with location. In Southern Atlantic Canada, sea level rise may be even greater than the global rate. Whereas, in Hudson Bay, sea level is projected to fall because the Earth’s crust is still rising, following the last ice age.

In areas of rising sea levels, the frequency of flooding and its associated impacts will increase. This may impact parts of the Quebec coastline, the northern Beaufort coast, and the Atlantic and Pacific regions. Increased flooding is likely to damage infrastructure and erode coastlines, putting communities at risk.

Storms

Large waves and storm surges, created by low pressure and high winds at the centre of a storm, 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.

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