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Wildfire

Wildfires are any unplanned or uncontrolled fire affecting natural, cultural, industrial and residential landscapes (adapted from FAO, 2010).

Wildfires are not a major cause of death, but they can be very destructive. Many wildfires are caused by human activities, either accidentally or as a consequence of carelessness, or arson. These fires often get out of control and spread over vast areas extending to tens or hundreds of thousands of hectares.

Even after the flames are gone, the health impacts of wildfires can linger for months—or years.

Research shows that wildfires can cause a large increase in gaseous air pollutants such as carbon monoxide, nitrogen dioxide, acetaldehyde and formaldehyde (Finlay et al., 2012). Wood smoke has high levels of particulate matter and toxins, Adverse health consequences can occur as a result of short- or long-term exposure. Respiratory morbidity predominates, but cardiovascular, opthalmic and psychiatric problems can also result (HPI).

Wildfires represent a hazard that is primarily influenced by humans and thus to a degree can be predicted, controlled and, in many cases, prevented. Wildfire occurence, characteristics and impacts are closely linked to other hazards: droughts, heat waves and extreme weather events can influence fire intensity and severity and thus the duration, size and controllability of wildfires. The effects of wildfires on vegetation cover and soil stability may create secondary hazards/subsidiary perils, such as post-fire landslides, mudslides, flash floods, erosion and siltation.

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Wildfire risks cascading impacts
The cascading effects of wildfires

    Risk factors

    • Increasing demand for agricultural lands for food and the necessity to use fire for land-use change.
    • The expansion of residential areas/infrastructures built near fire-prone vegetation - the Wildland Urban Interface (WUI).
    • Extended periods of drought and extreme heat.
    • Wildfires cause more land degradation (soil erosion, loss of land productivity) and as a consequence create more flooding and landslides.
Costs of wildfires
The invisible costs of wildfires

Vulnerable areas

  • Agricultural and pasture lands in which fire is used for controlling weeds, bush encroachments, and for land clearing.
  • Fire-prone natural forest, bush land and grassland ecosystems with high occurrence of natural fires in the subtropics or northern latitudes.
  • Agricultural and forest plantations.
  • Residential areas or scattered houses/infrastructures nearest to fire-prone vegetation.
  • Residential areas or individual structures made of easily flammable materials.
  • Abandoned rural villages and human settlements with no one to manage, prevent or respond to wildfires.
How to reduce wildfire risk

Risk reduction measures

  • Limit development in high bushfire risk areas.
  • Clear the vegetation surrounding homes and other structures.
  • Build fire lanes or breaks between homes and any forested or bush land areas, if a natural firebreak does not exist.
  • Plant vegetation of low flammability.
  • Use fire-resistant building materials.
  • Use traditional and advanced methods of prescribed burning for sustainable agriculture and flora and fauna management.
  • Enact legislation and regulation at the appropriate jurisdictional levels.
  • Conduct community-based fire risk minimization activities during all stages of fire management.
  • Provide community alerts through fire danger rating systems.
  • Educate the community and raise public awareness about the risks of wildfires.
  • Develop firefighting capacities and public safety.

Explore 5 smart and proven ways to reduce wildfire risk before fires start.

Latest Wildfire additions in the Knowledge Base

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Update

Do you have the sense that summers feel different than when you were younger? That they start earlier, arrive quickly and remain intense until the fall?

Conversation Media Group, the
Grand Canyon National Park South Rim Landscape with North Rim wildfire, forming part of the Dragon Bravo mega fire of Summer 2025
Research briefs

ASU researchers turn to fungi as a cost-effective, sustainable way to stabilize land after a fire.

Arizona State University
Update

For the past five years, the Union of Concerned Scientists has been tracking the climate extremes of what we call “Danger Season”—the period between May and October when North America is hit hardest by extreme weather.

Union of Concerned Scientists
Climate, the environment and site management – overview thumbnail
Documents and publications

Site Management translates climate and environmental commitments into concrete, site-level action across multiple contexts.

Global Camp Coordination and Camp Management Cluster
Update

A therapist says many of his patients are still struggling with mental health consequences, three years after the disaster.

Yale Climate Connections
Research briefs

Artificial intelligence is beginning to transform climate science, not just by improving forecasts, but by helping researchers understand the physical forces shaping the planet’s future.

University of Virginia
Research briefs

Scientists found that low autumn snow levels in western Eurasia are associated with dry, warm winters in California, increasing the Golden State’s wildfire risk.

Eos - AGU
Effects of extreme events thumbnail
Documents and publications

In this Focus issue, we highlight the many and varied effects of extreme events on biodiversity, and how the increasing frequency of these events under climate change is threatening life on land and in water.

Nature Ecology & Evolution (Springer Nature)
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