The Growing Threat of Wildfires in a Warming World

Wildfires have always been part of Earth’s natural cycle, shaping ecosystems and influencing landscapes for millions of years. But something has fundamentally changed. As global temperatures rise and weather patterns shift, fires are burning hotter, spreading faster, and lasting longer than ever before. This isn’t just an environmental issue-it’s a growing crisis that affects air quality, carbon cycles, public health, and the very ecosystems that support life on our planet.

How climate change fuels wildfire frequency
Longer fire seasons, greater risk
Carbon emissions from wildfires: a dangerous cycle
The dual impact on carbon sinks
Natural fires versus destructive fires: understanding the difference
The ecological role of fire
When fires become destructive
Regional hotspots and global patterns
Looking ahead: adaptation and mitigation

How climate change fuels wildfire frequency

The relationship between climate change and wildfires operates like a feedback loop. Warmer temperatures, extended drought, and a thirsty atmosphere have been key drivers in increasing wildfire risk and extent, particularly in the western United States over the past two decades. When spring arrives earlier and summers grow hotter, vegetation dries out more quickly, creating tinderbox conditions that make ignition almost inevitable.

Research from NASA’s Terra and Aqua satellites reveals that extreme wildfires have become more frequent, more intense, and larger over a 21-year monitoring period. The largest increases in extreme fire behaviour occurred in temperate conifer forests of the Western U.S. and boreal forests of northern North America and Russia. A particularly concerning finding is that warmer nighttime temperatures now allow fire activity to persist overnight, something firefighters historically relied upon as a reprieve.

New data from the World Resources Institute confirms that forest fires are burning more than twice as much tree cover today compared to 20 years ago, largely due to climate change. In 2024, fires were responsible for nearly half of all tree cover loss in tropical primary forests like the Amazon and Congo Basin-ecosystems critical to storing carbon, protecting biodiversity, and regulating local climates.

Longer fire seasons, greater risk

Fire seasons are starting earlier in spring and extending later into autumn. Research shows that parts of the Western United States, Mexico, Brazil, and East Africa now have fire seasons that are more than a month longer than they were 35 years ago. This extended window of vulnerability means more opportunities for ignition and spread.

The 2023 Canadian wildfire season offers a stark illustration of this trend. Canada’s warmest and driest conditions since 1980 fuelled extreme fires that lasted for five months. NASA researchers found these fires released approximately 640 million metric tons of carbon-more than Russia or Japan emitted from fossil fuels in all of 2022.

Climate projections paint a concerning picture for the future. With continued high greenhouse gas emissions, models project the risk of very large wildfires could increase by up to six-fold in parts of the United States by mid-century. In the Southeastern United States, modelling suggests at least a 30 percent increase in area burned by lightning-ignited wildfire by 2060.

Carbon emissions from wildfires: a dangerous cycle

When forests burn, they release massive quantities of greenhouse gases that have been stored in vegetation for decades or even centuries. Wildfires release carbon dioxide, methane, and nitrous oxide-all potent greenhouse gases that contribute to further warming. The combustion process also produces black carbon, brown carbon, and ozone precursors that affect atmospheric chemistry on regional and global scales.

A major study published in Science revealed that carbon dioxide emissions from forest fires have surged by 60% globally since 2001. In boreal forests of Eurasia and North America, fire emissions nearly tripled during that same period. The carbon combustion rate-a measure of fire severity based on carbon emitted per unit area burned-increased by almost 50% across forests globally between 2001 and 2023.

The dual impact on carbon sinks

Wildfires affect climate in multiple ways beyond direct emissions. When forests burn, they not only release stored carbon but also reduce the capacity of ecosystems to absorb CO₂ through photosynthesis. This double impact is particularly concerning because forests serve as crucial carbon sinks that help regulate atmospheric CO₂ levels.

The damage continues even after flames are extinguished. Trees killed by fires but left standing continue to decompose over subsequent decades, releasing additional carbon dioxide into the atmosphere. Dead trees also cannot absorb atmospheric CO₂ like living trees would. In severe cases where land erosion occurs after a wildfire, no carbon is reabsorbed until reforestation projects are initiated.

This creates a troubling feedback loop: as CO₂ emissions accumulate and California experiences more warming, extreme heat events, droughts, and invasive species, the risk and intensity of fires also increases, pushing the terrestrial carbon cycle further out of balance.

Natural fires versus destructive fires: understanding the difference

Not all fires are equal in their ecological impact. Fire is a natural part of many landscapes, and certain plants and animals have evolved to depend on periodic wildfires for ecological balance. Small, low-intensity fires help rejuvenate forests and are overall beneficial for conservation.

The ecological role of fire

Ecosystems benefit from periodic fires because they clear out dead organic material. When dead or decaying plants build up on the ground, they may prevent organisms within the soil from accessing nutrients or block animals from accessing the soil. This coating of dead organic matter can also choke out growth of newer or smaller plants.

Prescribed fire stimulates soil productivity, which benefits the entire ecosystem through nutrient cycling. When plant material is burned, nutrients are returned to the soil, essentially acting as a reset that enriches the ground for new growth. Without fire, the structure and species composition of plant communities changes, often favouring fire-intolerant, shade-loving species that crowd out fire-dependent plants and create ideal conditions for invasive species.

Many ecosystems depend on routine fire to thrive. Periodic lightning-ignited fires historically occurred approximately every three to 15 years in Virginia’s forests, facilitating nutrient cycling, catalysing seed germination, and creating diverse habitats for wildlife. Throughout Virginia alone, more than 100 different rare plants benefit from prescribed fire.

When fires become destructive

The problem arises when fires burn with unprecedented intensity and frequency, transforming from ecological tools into destructive forces. Hundreds of years of fire suppression has caused notable changes from historical patterns on the landscape, driving the increase of devastating wildfires we have seen over the past two decades.

When fire suppression leads to decades of fuel buildup and climate change creates warmer, drier conditions, the potential for extreme fires increases dramatically. These high-intensity wildfires can decimate native trees, incinerate organic matter in the soil, and fundamentally alter ecosystems for decades.

Fire suppression in frequent-fire forests led to a buildup of fuels that now results in carbon-emitting megafires under extreme fire weather. The conditions for such fires are occurring more frequently due to anthropogenic climate change. However, reducing tree density through prescribed fire and understory fuel reduction projects can mitigate high-severity fire and increase carbon storage, even with climate change.

Regional hotspots and global patterns

Northern high-latitude regions are warming at a faster rate than the rest of the planet, contributing to longer fire seasons, greater fire frequency and severity, and larger burned areas in boreal forests. In 2024, fire-related tree cover loss in the tropics peaked at over 4 million hectares-more than the previous three years combined.

El Niño events, which recur every 2-7 years and cause high temperatures with below-average rainfall, heavily influence fire seasons in tropical regions. Almost all fires in the tropics are started by people rather than natural causes like lightning strikes. Managed fires commonly used to clear land for pasture or agriculture can escape and escalate, with warmer and drier conditions fuelling their spread.

In the Mediterranean basin, heatwaves and summer droughts play a dominant role in driving fire activity. In 2022, record-breaking heat and drought in Spain resulted in more than 70,000 hectares of forest burned-the largest amount since 2001. Large plantations of highly flammable non-native species, like Eucalyptus, combined with extreme weather, have created ideal conditions for catastrophic fires.

Looking ahead: adaptation and mitigation

Addressing the wildfire crisis requires action on multiple fronts. Reducing global greenhouse gas emissions remains essential to limiting the warming that drives extreme fire weather. But communities must also adapt to a future where fires are more frequent and intense.

Communities, builders, homeowners, and forest managers can reduce wildfire impacts by discouraging developments near fire-prone forests through smart zoning rules, increasing space between structures and nearby vegetation, incorporating fire-resistant design features in buildings, and developing recovery plans before fires strike.

Restoring fire as a management tool offers another path forward. Fire, often paired with cattle or bison grazing, can control trees, woody shrubs, and invasive species while maintaining grassland health. Indigenous peoples have recognised the importance of fire as a land management tool for millennia, and modern land managers are increasingly drawing on this traditional knowledge.

The challenge of wildfires in a warming world demands that we understand fire not as simply good or bad, but as a force that requires careful management. In ecosystems adapted to fire, excluding it causes problems. In a warming climate, uncontrolled fires become catastrophic. Finding the balance between these extremes will be one of the defining environmental challenges of our time.

What do you think? How might your community better prepare for increasing wildfire risk, and what role should prescribed burns play in forest management where you live?

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Table of Contents

How climate change fuels wildfire frequency 🔗

Longer fire seasons, greater risk 🔗

Carbon emissions from wildfires: a dangerous cycle 🔗

The dual impact on carbon sinks 🔗

Natural fires versus destructive fires: understanding the difference 🔗

The ecological role of fire 🔗

When fires become destructive 🔗

Regional hotspots and global patterns 🔗

Looking ahead: adaptation and mitigation 🔗