This week, International Insight takes a break from geopolitics and dives deep into the science behind a natural disaster that has been repeatedly impacting communities across the globe: wildfires.

Just months ago, wildfires tore across the West Coast of the United States. Now, Europe is facing the same challenges Californians faced as wildfires ravage Spain.

But first, let’s explore what actually causes wildfires:

What causes wildfires?

Wildfires are formed at the combination of three key components: fuel, a heat source, and oxygen – known together as the fire triangle.

However, the issue with wildfires isn’t simply that the forest is on fire. It’s the magnitude and severity of the fire that actually makes wildfires – specifically ones similar to the wildfires in California earlier this year or in Spain currently – dangerous.

While many associate wildfires and forest fires with death and destruction, these fires can actually sometimes be healthy for the environment. In fact, for thousands of years, Native Americans would set or allow controlled fires to burn through parts of the forest to clear dead plants, promote growth, and stimulate ecological diversity. 

Now, modern science and technology promotes the careful implementation of “controlled” or “prescribed” fires. Rather than allow fires to spark into existence by themselves, ecologists, government officials, or other experts will carefully map out and plan to set certain sections of the forest on fire on purpose, identifying exact areas of the forest to set ablaze, determining how to manage any smoke, and working out public safety logistics. 

Through these “controlled burns,” specialists hope to preemptively remove dead leaves, trees, and other debris that would serve as quick kindling and potentially act as that first component (fuel) for a wildfire, as well as destroy non-native species that could harm an ecosystem, reduce or destroy hazardous fuels already present in the ecosystem, minimize the spread of disease and pests, promote growth of new vegetation, recycle key nutrients back into the soil, and further improve the ecosystem.

From an ecological standpoint, these small, controlled burns could serve as the perfect natural “disaster” to prevent keystone species and other apex predators from completely dominating an ecosystem. Instead, these prescribed fires would provide an opportunity to destabilize the ecosystem just enough to shift hierarchies and would promote ecological diversity.

But what if these fires consume the entire forest? What if they burn for weeks?

According to NASA, these destructive kinds of forest fires are becoming increasingly more common with “extreme wildfire activity…doubl[ing] worldwide… [and extreme wildfires growing] more frequent, more intense, and larger.”

The reason? Human activities driving climate change and wreaking havoc on the environment.

First and foremost comes the decades of active suppression of any and all fires, including beneficial burns, which leads to a “buildup of fuels in some forests”, achieving the first condition of the fire triangle.

Second: the impact of climate change. As global temperatures continues to rise with the last 10 years the warmest on record, according to NASA, “hotter weather, earlier melting of winter snow, warmer nighttime temperatures, and decreasing summer rainfall” all contribute to the creation of hotter and drier conditions that are perfect for the inception of wildfires, achieving the second factor of the fire triangle.

In addition to the ever-present oxygen in the atmosphere (the third condition of the fire triangle), all it takes is one spark to set off a fire. And sparks are easy to find.

According to the NPS (data from 2000-2017), almost 85% of U.S. wildland fires are caused by humans with causes ranging from intentional arson to unattended campfires and neglected cigarette butts to burning debris and equipment malfunctions.

One spark from a human misstep or unfortunately placed lightning strike and decades of neglect and built-up heat and fuel implode into a wildfire that spreads far and wide and burns bright for weeks on the backs of our ever-hotter climate.

And the destruction and death caused by wildfires don’t just stop with the fire itself.

According to NASA, wildfires also contribute significantly to global carbon dioxide emissions. From 2001 to 2023, carbon emissions as a product of forest fires increased by 60% across the world with Canada’s 2023 wildfires alone releasing 640 million metric tons of carbon dioxide into the atmosphere. And of course, more carbon dioxide in the atmosphere feeds back into the cycle of climate change and promotes the development of an even hotter climate.

The situation in Spain – 

For now, the situation in Spain continues to remain dire. Despite “temperatures dropping across the Iberian Peninsula,” AEMET, Spain’s weather agency, continues to report “‘very high or extreme’ fire risk[s]” with over 1,475 square miles of land – “twice the size of metropolitan London,” according to NPR – being burned by the wildfires.

In addition to the thousands of firefighters deployed to hold the flames at bay, Spain’s soldiers have also stepped up to the challenge, aiding firefighters alongside water-bombing aircrafts.

The situation is almost the same in Portugal with over 3,700 firefighters actively fighting the flames and 907 square miles – “nearly 5 times more than the 2006-2024 average for this period” – burned by the wildfires.

To make matters worse, authorities suspect that many of the flames were a direct product of human activities – namely, arson. 23 people have been detained in Spain for suspected arson and 89 more are currently being investigated.

While there is little to do about the flames blazing through the Iberian Peninsula currently, there is much we can do to prevent this kind of catastrophe – and the ones that unfolded in California – from occurring again.

First and foremost, take responsibility for your actions. Ensure that you don’t leave fires unattended and clean up after yourself to prevent any potential spark that could set off a flame.

Second – and perhaps more importantly, advocate for policies and actions to prevent climate change. Our climate will only continue to grow hotter and drier and more and more susceptible to disasters like these if we allow the situation with climate change to worsen. 

The only “prescribed burn” for this forest of wildfires is to address climate change as efficiently and effectively as possible.

Because the longer we wait, the higher and hotter the flames will burn.