Climate change in Canada

Climate change in Canada is a complex issue. While some researchers say that Canada may be among the countries least negatively affected by global climate change, others predict a less positive future. Although by some estimates farming and recreation industries might see benefits, forestry and timber production would likely see tremendous losses. Furthermore, the disruptions to the supply chain caused by extreme weather events have far-reaching consequences for many areas of the economy and the quality of life in Canada.

The effects of global climate change have been evident for decades and have a significant effect on the northern regions of the globe. Because almost 40 percent of Canada’s landmass is Arctic and Northern, a great deal of evidence indicates that global climate change will have a considerable impact on the country and continent overall. Canada released its first national climate plan, the Pan-Canadian Framework on Clean Growth and Climate Change, in 2016. Canada ratified the Paris Agreement, an international plan to reduce greenhouse gas emissions, that same year.

Background

Earth’s atmosphere is a bubble of gases and water vapor that extends about 62 miles from the surface. It shields the planet from ultraviolet solar radiation that can be dangerous to life. The work of many scientists led to a greater understanding of how this takes place and how changes to the atmosphere affect life on the planet.

In the 1820s, French mathematician and physicist Joseph Fourier wondered what was responsible for Earth’s average temperature and why the energy from the sun does not heat the planet until it is as hot as the sun. He concluded that invisible infrared energy carries the heat energy away from Earth into space. In 1824, he calculated that without an atmosphere, the planet would be much colder, so he concluded the atmosphere prevents some heat energy from escaping. In trying to explain his ideas about this delicate balance, he referred to a common experiment involving a box with a glass cover and sunlight. The sunlight warms the air inside the box, but the heat cannot escape. Although this is not precisely how the atmosphere works, people understood the air inside greenhouses was warmed in the same way and eventually people described it as the greenhouse effect.

American amateur scientist Eunice Foote conducted experiments in a similar vein in the mid-nineteenth century. She compared temperatures in glass cylinders filled with various gases. She discovered that water vapor combined with carbon dioxide, or carbonic acid gas, raised the temperature. Geologists at that time were discovering that the atmosphere contained much higher levels of carbon dioxide long ago when coal deposits were forming. Foote hypothesized that if carbon dioxide levels were higher in the past, Earth would have been much warmer. Her paper on the subject was published in 1856 in the American Journal of Science and Arts.

Three years after Foote reached her conclusions, Irish physicist John Tyndall conducted more sophisticated experiments. These enabled him to understand that the greenhouse gas effect was caused not by visible sunlight. Instead, he found that water vapor, carbon dioxide, and other gases absorb and emit thermal infrared energy.

Other scientists enhanced the previous understanding of the effects of carbon dioxide in the atmosphere on global climate. In the 1950s, Gilbert Plass developed the carbon dioxide theory of climate change. He calculated that the planet would warm more than 6 degrees Fahrenheit should the carbon dioxide in the atmosphere double. He also predicted that carbon dioxide levels would increase 30 percent over the twentieth century.

Climate science in modern times examines the effects of hydroxyl radical (OH). This highly reactive gas is formed from a reaction of water vapor and excited atomic oxygen. It helps control concentrations of carbon monoxide, higher hydrocarbons, hydrogen sulfide, methane, and sulfur dioxide through oxidation. The concentration of OH seems to track across the globe because it is evident in the atmosphere above whichever part of the planet is receiving direct sunlight. Higher levels of OH are measured above populated land areas and likely indicate pollutants commonly emitted by automobiles and industrial facilities. OH removes some of these chemicals from the atmosphere, but methane consumes OH, so less is available to improve the air quality. Scientists are working to understand how quickly it happens and OH’s effectiveness changes over time.

Overview

Climate change is having a significant impact on Canada. The Arctic is warming three times faster than the rest of the globe, which has implications for the planet’s climate and ecosystems in the region. According to Canada's government in 2024, the temperature in Canada has increased roughly twice as much as most other countries. From 1948 to 2023, the temperature increased 35.6 degrees Fahrenheit (2 degrees Celsius). This increase was greatest in northern Canada. Human activity was responsible for more than half of the warming. The rapid climate change in Canada is part of a cycle of change. Warming global temperatures have caused snow and sea ice loss. This, in turn, causes surfaces to absorb more solar radiation, which further increases surface warming and ice and snow melt. Climate change may impact the country’s agriculture, land, economy, and health, among other effects.

Thawing Permafrost

Permafrost is ground that remains frozen for at least a two-year period and, in many cases, has remained frozen for hundreds of thousands of years. During warmer months the top layer thaws, and in modern times thawing occurs at a greater depth than in the past. Bacteria then break down the biomass, causing the release of carbon dioxide and methane. Researchers are working to understand how much of these greenhouse gases will be released due to this thawing and what impact it will have. Furthermore, the loss of permafrost is destabilizing structures. Entire communities in the Arctic that have existed on coastal sites for thousands of years are collapsing into the ocean.

Boreal Forest Wildfires

Forest fires are a normal part of the natural cycle. However, due to global climate change, Canada is seeing more frequent and destructive boreal forest wildfires. These are particularly devastating in the Northwest Territories. Fires typically leave charcoal in their wake, but intense wildfires are burning into the organic materials that carpet the forest floors. This puts carbon that was locked in the soil into the atmosphere.

Forests typically offset carbon emissions because trees use carbon dioxide in the photosynthesis process. Trees in a forest become storehouses of carbon. Forest fires not only release stored carbon, but also reduce the number of trees available to store more carbon.

Coastal Concerns

Rising sea levels are predicted to affect communities around the globe. The sea-level rise is caused in part by glacial and ice sheet melt. Thermal expansion is another factor because water expands as it warms. Nearly half of sea level rise since the 1990s is due to thermal expansion.

Canada has more than 150,000 miles of coast. Some estimates indicate that sea levels could rise from about 10 inches (26 centimeters) to about a yard (1 meter) by 2100. This could have a dramatic effect on the coastline, pushing it farther inland. Large population centers could be inundated and structures lost. The economic and human toll of loss of these lands would be significant. For example, more than 20 percent of the land of Surrey in British Columbia is within the coastal floodplain area.

Less obvious perhaps is the impact that rising sea levels would have on wetlands and marshes. These areas protect the coast by slowing ocean waves, buffering the land against storms, and reducing erosion. Rising seas would push saltwater into these areas, killing water plants and burying many wetlands. Another impact would be on waterfowl and other wildlife. Many birds nest in wetlands and marshes. They feed on small fish and birds that in turn feed on crustaceans and invertebrates. Young salmon on the Pacific Coast take refuge in salt marshes; salmon are a primary food source of killer whales. Loss of healthy wetlands reduces species diversity.

As saltwater pushes inland, it encounters hills and similar higher terrain unsuited for wetlands. As groundwater becomes increasingly salty, trees find it more difficult to pull in water. Many will die.

Effects on Wildlife and Biomes

Many early reports on the effects of climate change focused on polar bears and their struggle to hunt seals as sea ice became fractured. This forced them to swim long distances and frequently move onto land. The fasting period when food is scarce has grown longer, and females often do not have fat reserves sufficient to feed their cubs. Some data suggests that most polar bears will be gone by the end of the twenty-first century if steps to address climate change are not taken; even if some emissions reduction is achieved, some populations would likely disappear.

Animals are also affected by climate change, notably changes in weather patterns such as winter rain. Caribou break through snow cover to forage for food. When rain falls on snow, it forms a layer of ice that the animals cannot punch through. Ice over snow also makes travel more difficult for many animals looking for food. Such events were rare, happening at most once a decade, but in the twenty-first century they happen almost annually. Wet, icy snow is also a problem because it slows down caribou, while smaller predators such as wolves can run them down on top of the ice. While the Peary caribou population was more than 40,000 in 1961, according to the Government of Canada in 2022, it had dropped to about 13,200. Much of this loss is linked to an increase in the number of days with temperatures above freezing.

The Canadian High Arctic Tundra is Canada’s northernmost ecoregion. It is characterized by permafrost that is hundreds of yards deep and very cold, dry conditions. The northernmost areas see the lowest precipitation in Canada. These dry conditions support sparse vegetation mostly consisting of lichens and mosses, although some plant species such as arctic willows and herbs grow in some lower elevations. However, in modern times researchers report many shrubs growing in areas where they were not previously found.

Economic Concerns

Agriculture stands to be considerably affected by climate change. Farmland would be lost to rising waters. Metro Vancouver could lose 10 percent of its agricultural land at a cost of more than $100 million in annual revenue. If climate change is not slowed, by 2100 the risk of extreme flooding in this area is projected to be 50 percent.

Population centers have invested considerable funding in protecting shorelines. For example, cities have upgraded dikes and replaced or repaired sea dams. Other communities have built riverfront nature areas and parks designed to reduce the impact of flooding. Among these methods is the establishment of channels and overland flow pathways to allow water to easily flow to the ocean, rivers, and other bodies of water.

Health

Evidence indicates that climate change is affecting human health in Canada. Indigenous populations, particularly in the North, have experienced increased food insecurity. Indigenous peoples also are threatened because travel via ice is increasingly risky. These and other issues affect mental health.

Heat waves have increased in number and duration and been linked to more cases of heat stroke and heat-related death. Pollution from wildfires has affected individuals with respiratory issues. Rising temperatures increase ticks, mosquitoes, and other transmitters of disease.

Anxiety and other mental health issues are another concern. Greater threat of fires and flooding increases stress and disrupts services. Many people affected by extreme weather events, fires, and floods experience post-traumatic stress disorder (PTSD).

Bibliography

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"Temperature Change in Canada." Government of Canada, 25 July 2024, www.canada.ca/en/environment-climate-change/services/environmental-indicators/temperature-change.html. Accessed 15 Nov. 2024.