Climate change and wildland fire

Wildland fire is an important environmental disturbance that shapes Canadian ecosystems. It alters the air, land and water. Natural fire cycles and reburn intervals vary across the country and over time. Global climate shifts are reflected in changes to the frequency, intensity, seasonality and extent of wildland fire.

Patterns associated with fire weather, fire regime, fire behaviour are changing. Warmer and drier conditions make the landscape more conducive to ignition and spread as fuels are more flammable and quicker to ignite. Wildland fire is increasing in some regions that historically saw less burning, including Arctic and sub-Arctic tundra, and parts of Atlantic Canada. Research by scientists at the Canadian Forest Service shows that Canada’s fire season is lengthening. Forests, grasslands and peatlands experience fires earlier in the spring and ending later into the fall. Emissions from large wildland fires are fuelling hotter and drier meteorological conditions, which in turn accelerate fire frequency and extent through a positive self-reinforcing climate-fire feedback loop.

Two key climatic factors influencing fire activity are temperature and moisture. These factors also impact forest pest outbreaks and extreme weather events, both of which increase the amount of damaged or dead vegetation to the fuel load. Changes to climate, combined with other factors such as expansion into the wildland-urban interface, historic fire suppression tactics and increased lightning strikes are leading to a larger number of ignitions, larger areas burned, and greater socio-economic and ecological impacts than historical averages.

Given the consequences, comprehensive and integrated fire management strategies emphasize a whole-of-society approach to prevention, mitigation, preparedness, response and recovery.

Climate-driven shifts to fire weather

Canada is warming at twice the global average rate due to its northern location. Rising temperatures, increasing evapotranspiration, and more frequent and severe fire weather conditions are causing more wildland fires to:

• ignite
• spread quicker
• burn hotter
• persist
• affect larger areas and more people

The frequency and intensity of wildland fires are influenced by various factors including:

• atmospheric stability
• temperature
• moisture (humidity, rain, snowpack, drought)
• cause of ignition (lightning vs human activities)
• wind
• vegetation (fuel type, load, availability)
• topography
• land-use
• other forest disturbances (disease / pest infestations)
• forest and fire management practices

Climate-driven shifts to fire regime

Climate change is transforming Canada’s fire regime because of:

• lengthy periods of drought
• altered precipitation patterns
• dried out vegetation
• fluctuating wind patterns
• extreme weather events (e.g., record breaking high temperatures, low precipitation, thunderstorms)

Changes in fire regime can have significant impacts on Canada’s forests, forest industry and inhabitants.

Analyses show that Canada’s wildland fire season has become longer. For example, in 2023, the annual fire season extended from mid-April to late October. By early April, a significant moisture deficit was occurring across the country. Prolonged drought and early snowmelt coincided with record-breaking heat. Coast-to-coast fire activity resulted in 14.6 million hectares (National Burned Area Composite, 2023) of forest area burning, which is four times the 10 year national average. Projections suggest that by 2100, Canada’s fire season may lengthen by more than a month in certain forest regions such as central and eastern Quebec and northern British Columbia. Forecasted changes in spring and fall temperatures will strongly influence fire season length, particularly in areas with reduced winter precipitation and early snowmelt.

Wildland fire emissions

Forests, grasslands and peatlands in Canada are vital for capturing and storing large amounts of atmospheric carbon. When these areas burn, a complex mixture of particulates, water vapour and gases is released into the atmosphere. Following a wildland fire, greenhouse gases (GHGs) continue to be emitted through the process of decomposition. As fires in the boreal forest increase in scale and severity, corresponding emissions will also rise.

The type and amount of GHGs released from wildland fire are estimated by modelling how different components (branches, trunks, roots, litter) burn. Canada’s annual National Inventory Report details emissions from human activities on managed land. Estimates from forest pest outbreaks and wildland fires are reported separately to clarify trends and account for annual variability in naturally caused emissions.

As forests regenerate their ability to store carbon is lower than older-aged stands. Post-fire GHG removal through natural regeneration is not reported until the stand reaches commercial maturity. Canada’s forest carbon reporting system is internationally recognized and used in many countries to estimate and understand forest emissions and removals. As the scale and severity of wildland fires have steadily increased, largely due to climate change, so has their impact on global GHG emissions.

Adapting to wildland fire

Preventing and reducing the risk of wildland fire is a key component of climate change adaptation. Equally important is reducing GHG emissions, which contribute to climate change. Proactive forest management has the potential to decrease fire intensity and/or fire risk by altering fuel load type and quantity.

Tools such as strategic spatial forest management planning models and landscape-level fire risk assessments may identify strategies that could affect wildland fire risk, such as:

• strategically harvesting stands with high fire risk
• planting broadleaf species for more fire and drought resilient forests
• considering the amounts of fuel on a landscape level when planning shorter-term treatments such as prescribed fire, cultural fire practices, fire breaks, or forest thinning and pruning

The CFS is advancing wildland fire research and activities to accelerate innovative adaptive forestry practices that reduce GHG emissions from wildland fires and support the forest sector as outlined in Canada’s National Adaptation Strategy.

Find out more

• Wildland fire monitoring and reporting tools
• Forest carbon
• Forest fires and climate change (Climate Atlas of Canada)
• Canada’s National Adaptation Strategy (Environment and Climate Change Canada)

Canadian Forest Service Publications

• Canadian wildland fire prevention and mitigation strategy: taking action together (2024)
• Blueprint for forest carbon science in Canada (2024)
• How does Canada report greenhouse gas emissions from wildland fire (2024)
• Fire-regime changes in Canada over the last half century (2019)