From the Depths: How Arctic Warming Fuels ‘Zombie Fires’

By: Sam Watanuki | Published: Jul 02, 2024

“Zombie fires,” smoldering underground during winter, mysteriously reappear in the spring across the peatlands of Alaska, Canada, and Siberia.

These fires defy the usual fire season, igniting as early as May, much to the puzzlement of scientists. Even scarier? They can persist for years, resurfacing from beneath the Earth’s surface.

A New Understanding of Zombie Fires

Traditionally, zombie fires were thought to be remnants of surface fires. However, recent research suggests that rapid atmospheric warming might cause peat soils to heat up to smoldering temperatures underground without any spark or ignition source.

A picture of a large fire in a field

Source: Wikimedia

This points to climate-change-driven spontaneous combustion as a potential cause.

Historical Context and Increasing Frequency

Zombie fires, once rare events, have increased significantly in the past two decades.

A view of a forest fire, with many trees on fire, seen in the evening.

Source: Matt Howard/Unsplash

Reports date back to the 1940s, but their frequency and intensity have surged alongside accelerated warming in the Arctic, the fastest-warming region on the planet.

A Growing Threat in 2024

In early 2024, more than 100 zombie fires were active in British Columbia, Canada.

View from above the Hog Butte fire in Alaska.

Source: National Interagency Fire Center/Wikipedia

Even in the coldest village on Earth, Oymyakon, Siberia, zombie fires have been recorded, accounting for around 3.5% of the area burned annually. These fires can carry over through multiple winters.

The Carbon Release Crisis

Peat soils in the Arctic trap more carbon than the entire atmosphere. Zombie fires release gigatons of carbon into the atmosphere, exacerbating global warming.

Smoke from Canadian wildfires spreads across a city in Minneapolis

Source: Wikimedia

This significant carbon release is a growing concern for scientists and environmentalists alike.

Microbes and the Hot Metastable State

The research unveiled a mathematical model showing how peat soils react to climate changes. It found that microbes breaking down the soil produce enough heat to keep peat smoldering at a sizzling 176°F throughout the winter.

A forest fire. The fire is in the forest's center, and trees surround it.

Source: Hector Quintanar/Getty Images

This newly discovered “hot metastable state” can persist for up to 10 years without any surface fire.


Climate Patterns and Triggers

Interestingly, a sudden transition to the hot metastable state can be triggered by climate patterns, including summer heat waves and global warming scenarios.

A photograph of a thermometer

Source: Freepik

The critical factor is the rate of atmospheric warming — a faster rate can trigger this transition, while a slower rate does not.


Real-World Implications

While this phenomenon has not yet been proven in real-world conditions, it has parallels in compost fires.

A photograph of a large wildfire burning in Canada

Source: CORBIS/Corbis via Getty Images

For example, a large fire in London during a 2022 heatwave was likely caused by a compost pile spontaneously combusting. This suggests that similar conditions could trigger zombie fires.


The Rate of Change Matters

Zombie fires exemplify a rate-induced tipping point, where rapid changes in external conditions push a system into an undesired state.

The side of a large mountain engulfed in flames

Source: Matt Palmer/Unsplash

The current climate may be nearing — or exceeding — critical rates of change, potentially explaining the recent increase in zombie fires.


Combating the Zombie Fires

To prevent further zombie fires, limiting climate variability is essential. While policymakers often focus on atmospheric temperature, the rate of change might be just as important, if not more.

A climate change rally with numerous people holding up signs

Source: Scott Olson/Getty Images

Addressing climate variability could be crucial for building resilience against these underground infernos.


A Vicious Cycle of Climate Change

As the climate warms and weather becomes more extreme, conditions that lead to zombie fires become more common.

A small plant is burning in the grass

Source: Freepik

This creates a vicious cycle: more fires release more carbon, worsening climatic changes, leading to more fires and extreme weather.


Looking Ahead

Understanding and addressing the root causes of zombie fires is vital.

A wildfire burns at night in a forest. Smoke raises in giant plumes through and above the trees.

Brendan O'Reilly/Wikimedia Commons

While more research is needed to confirm the findings in real-world conditions, it’s clear that mitigating climate change and controlling the rate of atmospheric warming are crucial steps in preventing these mysterious and destructive fires.