• scenic view of trees in a forest during a wildfire

Wildfires

Wildfires are uncontrolled fires that occur in nature and can be caused by humans or intensified by adverse weather conditions.

The causes of wildfires are varied. Among the most common are human activities, such as land burning for agriculture and illegal logging, as well as adverse weather conditions, such as prolonged droughts and high temperatures. Long periods of drought, characterized by a lack of precipitation and soil moisture deficit, significantly affect the hydrological balance and increase evaporation. These conditions can be further aggravated by heatwaves, which intensify the overall impacts and elevate the risk of wildfires. Other factors, such as wind, vegetation, topography, and forest management practices, also contribute to this risk.

The combination of these various factors can increase both the frequency and intensity of wildfires. Additionally, besides climate change, the growing urbanization of rural areas also contributes to extending the wildfire season.

 

Situation in the Region of the Americas

Globally, these events are becoming more extreme in terms of hectares burned, duration, and intensity. In the Americas, there has been an increase in the frequency, severity, and duration of wildfires, which intensifies the need to understand their effects on public health. According to a recent report, in 2022, the population was exposed to average ambient temperatures 0.38°C higher than in the period 1986-2005. Paraguay experienced the highest anomaly (+1.9°C), followed by Argentina (+1.2°C) and Uruguay (+0.9°C). Additionally, between 2000-2009 and 2013-2022, there was a 140% increase in heat-related mortality.

2024 was particularly devastating due to the impact of the El Niño phenomenon, which has worsened drought in many regions, amplifying conditions that favor the spread of wildfires. Several South American countries experienced a notable increase in the intensity of fires during August and early September, due to prolonged drought characterized by a lack of rainfall and soil moisture deficit.

Access the daily Natural Hazards Monitoring reports for updates on extreme weather events in the region, including wildfires.

 

Impact of Wildfires

Health Impact: In terms of health, inhalation and exposure to smoke and ash can cause various conditions ranging from skin irritation to exacerbation of chronic respiratory or cardiac conditions. The direct risks of wildfires include burns, physical injuries, heatstroke, and in extreme cases, death. Additionally, wildfires can disrupt the supply of medications and healthcare services due to damage to infrastructure and service outages.

Some effects of wildfires can last for years. The loss of property and forced displacement can have severe mental health consequences, causing post-traumatic stress, depression, and insomnia.

Wildfires can also lead to indirect consequences, such as food shortages due to the destruction of crops.

Environmental Impact: Wildfires can have devastating consequences for ecosystems. The smoke from wildfires releases large amounts of carbon dioxide and other greenhouse gases into the atmosphere, contributing to the climate change cycle and affecting air quality.

Socioeconomic Impact: Wildfires near populated areas can have a significant impact on the environment, human health, animal health, and the economy. These events affect city infrastructure and can cause disruptions in transportation, communications, water supply, and energy services.

The extent of the impact of these events depends on the size, speed, and proximity of the fire, as well as the issuance of early warnings for evacuation. Therefore, risk communication and community engagement play an important role in both preparedness and response to such events.

Health Risks

Wildfire smoke consists of a combination of gases and tiny particles that originate from the burning of materials such as trees, vegetation, and structures. This smoke can immediately affect health, even in healthy individuals, causing irritation in the throat, eyes, nose, and skin, and affecting the respiratory system, leading to coughing and difficulty breathing.

Wildfire smoke can trigger asthma attacks and respiratory problems and/or exacerbate pre-existing health conditions. In some cases, the small particles in the smoke can penetrate deeply into the lungs, causing inflammation and damage to lung tissue.

 

Certain populations are more susceptible to the effects of wildfire smoke based on their demographic group and pre-existing health conditions. Additionally, workers involved in emergency response are at higher risk due to their level of exposure. Other factors, such as location or specific cultural or socioeconomic characteristics of certain communities, can also influence the level of impact or vulnerability to wildfires.

Vulnerable groups include:

  • People with asthma or other chronic respiratory conditions, individuals with pre-existing cardiovascular conditions, as well as older adults, children, and pregnant women, are more susceptible to the effects of smoke and ash.
  • Remote or hard-to-reach areas, indigenous communities, people living in poverty, and populations facing a socioeconomic crisis have greater challenges in accessing healthcare services, receiving humanitarian aid, and restoring basic services after the impact of wildfires.
  • Due to the nature of their work, firefighters and other first responders are more exposed to injuries, burns, and inhalation of smoke at high concentrations during wildfires.
  • People who work outdoors, as they have greater exposure to polluted air.

 

  • Respiratory conditions: Asthma, chronic obstructive pulmonary disease, cystic fibrosis, interstitial lung disease (idiopathic pulmonary fibrosis), lung cancer, and lung transplant.
  • Cardiovascular conditions: Coronary artery disease (including a previous myocardial infarction), heart failure, and hypertension.
  • Endocrine or metabolic disorders: Diabetes, obesity, and metabolic syndrome.

Very high risk

  • Malnutrition: Drought has a severe impact on food security, increasing malnutrition. The lack of precipitation and reduced water resources decrease agricultural production, raising food prices and making it difficult to access an adequate diet.

  • Waterborne diseases: Drought increases the risk of waterborne diseases, such as cholera, shigellosis, hepatitis A and E, and leptospirosis. These diseases can become more prevalent during droughts due to the scarcity of clean water.

  • Vector-borne diseases: During drought, the risk of vector-borne diseases, such as those spread by mosquitoes, increases significantly. The lack of surface water can lead people to store water in containers, creating ideal habitats for mosquitoes like Anopheles, which transmit malaria, or Aedes aegypti, which transmit dengue, chikungunya, Zika, and urban yellow fever.

High Risk

  • Rodent-borne diseases and other zoonoses: The lack of water and food during drought can attract rodents to inhabited areas, increasing the chances of contact with people.

  • Heat stress and air pollution: Excessive heat can cause exhaustion, heatstroke, and worsen cardiovascular, renal, and respiratory diseases, diabetes, psychological disorders, and asthma, and may lead to premature deaths and disability.

  • Mental health and psychosocial support: Emergencies create problems at individual, family, community, and social levels, affecting mental health with disorders such as anxiety and depression.

  • Respiratory diseases: Respiratory health can be severely affected by decreased air quality and increased pollution during a drought.

Moderate Risk

  • Violence and gender-based violence: The lack of access to services and the scarcity of essential goods, including food and clean water, increase stress and tensions in communities, which can lead to violent confrontations.

  • Vaccine-preventable diseases: The risk of vaccine-preventable diseases such as measles, rubella, polio, and diphtheria can increase during a drought.

  • Chronic non-communicable diseases: Morbidity and mortality due to chronic non-communicable diseases tend to worsen during periods of population stress, especially in contexts with limited access to healthcare.

Low Risk

  • Maternal and child health deterioration: Pregnant women are especially vulnerable during natural threats. Adverse conditions and limited access to medical treatment can lead to obstetric complications, increasing the risk of neonatal and infant mortality.

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