The Effect of the Canadian Wildfires on Trees and our Climate

Canada wildfires are burning out of control this summer as a result of intensifying climate change. According to data from the Canadian Interagency Forest Fire Center, around 1.3 million hectares (3.2 million acres) have burned so far compared to the average 55,050 hectares seen for the past twenty years. Canada is accustomed to wildfires, however, this wildfire season has been particularly fierce and longer than previous ones. This creates a dangerous climate threatening human health and ecosystems.

Wildfires can be a beneficial, natural process for ecosystems. Fire can help replenish forests by clearing out dead organic material, spreading seeds, and killing invasive species. For example, pine tree seeds are found within pinecones which must be melted by fire for the seeds to be released. Many species of plants and animals in fire-prone areas have adapted to these natural phenomena unlike invasive species not native to the area. However, when fires persist and are out of control– as seen this season– they can cause more harm than good. If ecosystems do not have enough time to recover from the fire, biodiversity can be harmed as species face extinction. Wildfires can also negatively impact infrastructure and humans in the surrounding areas due to the large amounts of smoke.

Three factors combine to start wildfires: fuel, an ignition source, and optimal wildfire weather. Dry grass, shrubs, or trees can be fuel for wildfires. The drier the vegetation and soil, the easier wildfires will spread. The ignition source of a wildfire can be natural such as a lightning strike or the Sun’s heat, however, 85% of the time it is caused by humans. Things like discarded cigarettes or campfires can be sources for wildfires. Also, the weather in the region is important in determining how far a wildfire will spread. Dry, hot, windy weather is optimal for quickly spreading wildfires. Wind helps spread fires and provides oxygen that helps sustain them.

Canada’s wildfire season usually occurs during the warmer months of the year, however, this season started earlier than usual and in a larger geographical region. Wildfires are common in Western Canada but they are exhibiting an increased frequency in the eastern parts of the country. The unusual nature of these wildfires can be attributed largely to climate change.

Because of global warming, temperatures in Canada are higher than previous years. The climate has also been particularly dry, with 50% less precipitation this spring. The recent vapor pressure deficit, which measures the atmosphere’s ability to pull moisture from vegetation, can be linked to climate change. The larger this deficit is, the greater the risk of wildfires. Research shows that the vapor pressure deficit has increased in recent decades as climate change has worsened. As climate change and global warming continue, more wildfires can be expected.

Paradoxically, climate change is accelerated as a result of these wildfires. Forests are carbon sinks, storing large amounts of carbon dioxide and producing oxygen. As trees burn down, this carbon is released into the atmosphere as carbon dioxide. Carbon dioxide is a greenhouse gas that traps outgoing heat in the atmosphere and contributes to global warming.

Human health is also impacted by wildfire smoke. Wildfire smoke is made up of particulate matter (a combination of solid particles and liquid droplets like dirt, dust, or soot). Various health effects can occur from both short and long term exposure to these air pollutants. Larger particles can cause eye, nose or throat irritation and smaller particles less than 2.5 micrometers (PM 2.5 or smaller) are an even greater concern. The small size of these particles enables them to penetrate the bloodstream and lodge deep in the lungs. By 2050, the health effects of air pollution are expected to cause 1,000 to 4,300 additional premature deaths nationally per year. An uptick in respiratory infections, heart disease, and lung cancer are expected as well. Scientists believe that wildfire smoke is even more toxic than a cigarette.

Wildfires are a result of climate change but, importantly, they are also an accelerant of climate change. One way to reverse this global climate impact is by replenishing the burned forests. By planting more trees, carbon dioxide can be taken out of the atmosphere, preventing global warming. Charities such as One Tree Planted are currently taking donations to help replant Canadian forests.