Wildfires and Climate Change

What are the Causes of Wildfires?

Points of Combustion

Wildfires can be natural or human-caused.

Natural causes include lightning strikes, volcanic eruptions, and even spontaneous combustion. Human-caused wildfires can be started by accident, such as from unattended campfires or discarded cigarettes, or intentionally, such as arson. Powerlines and other electrical sources also ignite fires.

Natural Causes: The danger from these events is now increased by human activity.

Lightning: This is the most frequent natural cause of wildfires. Lightning strikes can generate tremendous heat, enough to ignite dry vegetation like leaves, branches, or trees. And the increase in size and frequency of storms that produce lightning has added to this danger.
Volcanic eruptions: Volcanic eruptions can spew hot lava, ash, and cinders, all of which can ignite nearby vegetation and start wildfires.

Human Caused Wildfires: These are quite common and account for a significant portion of wildfires globally. Some common examples:

Unattended campfires: Campfires that are not properly extinguished or left unattended can easily spark a wildfire, especially in dry conditions that are now more common with drought and extreme heat on the increase.
Discarded cigarettes: Cigarette butts that are not extinguished properly can ignite dry leaves or grass and start a fire.
Debris burning: Burning yard waste or other debris can be a fire hazard, particularly if not done with proper precautions and during dry, windy conditions.
Equipment malfunctions: Sparks from malfunctioning tools or machinery can ignite dry vegetation. This also includes downed power lines and other damaged electrical components.
Arson: Intentionally setting fires is a serious crime and a major cause of wildfires.

Human causes, both individual and collective, continue to play a major factor in the increasing number of wildfires.

What is Driving the Increase in Wildfires?

The Sources

There isn’t a single villain behind the rise in wildfires, but rather a combination of culprits.

Climate Change: This is considered the primary driver. Climate change does not cause individual extreme weather events. A warming planet translates to drier conditions, heatwaves, and longer droughts, thus creating a perfect environment for wildfires. Dry fuel ignites more easily and burns hotter. The science suggests that climate change has already lengthened fire seasons, increased fire frequency, and led to larger burned areas. The U.S. Drought Monitor provides a weekly snapshot of the areas of drought – hotspots for increased fire activity.

Land Use and Fuel Buildup: Changes in how we use land can worsen wildfires. Urban sprawl pushes development closer to wildlands, creating a dangerous interface zone. And in some areas the choice to build in the midst of or close to forested areas, puts human habitation at risk as well as increasing the fire hazards close to the wild areas. Additionally, fire suppression practices over many years has resulted in an unnatural buildup of flammable vegetation on forest floors. This creates a bigger tinderbox for wildfires to explode when ignited. Experts in forest management are re-examining long standard practices that have moved away from controlled burns and clearing of undergrowth. Basically human activity ranging from individual choices to the presence of powerlines through forested area enhances the possibility of fire as intensified by Climate Change.
Invasive Species: The introduction of non-native plants like cheatgrass can increase fire risk. These invasive species tend to be highly flammable and can create continuous fuel beds that fires can race across.

What and Where are the Greatest Dangers and Health Threats from Wildfires?

The Dangers

Global temperatures and the frequency and intensity of heatwaves will rise in the 21st century as a result of climate change creating many of the conditions conducive to wildfire outbreaks particularly drought and conditions that produce lightning (the major natural cause of forest fires).

Fast moving fires: According to the National Weather Service, for example, most forest fires in the Inland Northwest U.S. are ignited by lightning. Many rangeland and wheatfield fires are also started by lightning. The majority of these lightning caused wildfires occur in the absence of or very little rain. When this occurs, the lightning is commonly referred to as “dry lightning”. Gusty winds often accompany thunderstorms which produce “dry lightning” which accelerate the spread of fires. Occasionally, the winds are in the form of strong microbursts resulting from rapid cooling of air below the thunderstorm where rain has evaporated. These thunderstorm winds can quickly turn smoldering organic material into a raging fire. Thunderstorm winds tend to be erratic in direction and speed, posing one of the greatest dangers for firefighters. This can quickly trap people and animals in the path of the fire, making escape extremely difficult.
Erratic fire behavior: Unlike controlled burns, wildfires can be unpredictable. Wind can cause them to change direction suddenly, jumping fire lines and creating spot fires far ahead of the main blaze. This erratic behavior makes them incredibly challenging to contain.
Extreme heat intensity: Wildfires can generate tremendous heat, not just from the flames themselves but also from burning embers that can be carried long distances by wind. This intense heat can incinerate entire structures and inflict severe burns on anyone caught in its path.
Low visibility and dangerous air quality due to smoke: The thick smoke produced by wildfires significantly reduces visibility. This can make it hazardous for firefighters to navigate the flames and for residents to evacuate safely. Smoke inhalation also poses serious health risks as evidenced by the smoke from the 2023 Canadian wildfires that blanketed much of the U.S.
Crown fires: These particularly dangerous wildfires burn not just in the undergrowth but also in the crowns of trees. Crown fires can move incredibly fast, leaping from tree to tree, and are very difficult to extinguish.

Two CalFire crew digging a fire line with orange flames near by. — A CalFire crew from Santa Cruz work to prevent fire from reaching a home while fighting the CZU August Lightning Complex fire in Bonny Doon northwest of Santa Cruz on Friday August 21, 2020. The fire was sparked by lightning and burned throughout broad regions of rural San Mateo and Santa Cruz counties. (Photo by David Royal)

The threats of Wildfires which were once most common in the Western U.S. during a “fire season” have now become a nearly year-round occurrence not only in the Pacific Northwest but in many other states, countries and regions from Canada to the Amazon as rain patterns shift with rising global temperatures.

Americares Responding to and Preparing for Wildfire Emergencies

Our Work

Recognizing that rising temperatures from Climate Change are increasing health risks to vulnerable populations around the world, Americares is working with our health care partners in clinics to prepare communities to meet the threat from wildfires and to provide life saving health services to those people most affected by these emergencies.

In the United States, we are working with Free Clinics to make them more Climate Resilient by providing resources for clinic staff and patients in the event of wildfire outbreaks.

Since 2018, Americares has been responding to the increased threats of wildfires.

In 2018, Americares responded to the Camp Fire burning in Northern California and the Woolsey Fire raging in Southern California. They ignited on the same day, November 8th, 2018. Together they burned more than 250,000 acres in California in one week – larger than the cities of Boston and Chicago combined. Officials reported 87 deaths and nearly 19,500 structures destroyed. The Camp Fire became the deadliest and most destructive wildfire in state history. We coordinated with national organizations and local partners to provide shipments of medicines and relief supplies to clinic partners affected by the disaster. Following Americares response to the devastating 2018 and 2019 California wildfires, the organization undertook a robust disaster preparedness and mental health initiative designed to build the capacity of safety-net health centers in fire-prone regions of California.
In 2020, the US experienced a record number of wildfires; more than 50,000 wildfires burned 8.8 million acres, consuming more than 2 million acres beyond the 10-year average and nearly double the wildfires in 2019. Hot, dry and windy weather across the West left parts of California, Oregon, Washington and Colorado under siege from the unprecedented 2020 fire season. These fires have been described as “apocalyptic” as the threats from climate change become all too real for many residents of these states. Fires generated smoke and ash throughout the West, compromising air quality for millions. Three US cities (Seattle, Portland and San Francisco) at one point were reported to have the worst air quality in the world. Our Emergency Team responded with support for health centers and partners, which included medicines, relief supplies, bottled water along with more training and preparedness for health workers. Americares sent 18 total shipments to 16 health centers and nonprofit partners in California, Idaho, Oregon and Washington along with grant support for 7 partners.

In 2023, we responded to the devastating Wildfires in Hawaii. These fires, spurred by dry conditions and strong winds in the aftermath of Hurricane Dora, swept through the Hawaiian Islands, killing 97 people, causing major destruction and displacing thousands across Maui, the Big Island, and Lahaina. The Maui wildfires that consumed the community of Lahaina are the deadliest in the U.S in more than 100 years according to the National Fire Protection Association. Americares deployed emergency teams to Hawaii and provided support for local partners including a modular clinic, mental health services along with medicines and supplies. We continue to work on the recovery phase of the emergency.

And it is crucial for everyone who is faced with the risk of wildfires to be prepared. Predicting wildfires is challenging but National Weather Service forecasters help land managers and firefighters by producing fire weather forecasts on a daily basis during the warm season. Forecasters also issue red flag warnings when the combination of dry vegetation and critical weather conditions will result in a high fire danger. Land managers typically inform the general public of the fire danger in National Parks, Forests and other public lands. During such warning periods, the general public is urged to avoid areas where they would be trapped in a fast-moving fire.

For more information on wildfires, visit the National Weather Service Wildfire page.