5 Graphics Explain the Climate-Fire Feedback Loop

Forest fires have become a harsh new reality for millions globally, with their impacts felt near and far. Over the last few years, fires have destroyed billions of dollars in property, displaced thousands of people and coated cities in choking smoke, causing deadly air quality.

It's no coincidence that fires are becoming more intense as the planet warms. Fires need hot, dry conditions to ignite and spread. While fire is a natural part of some forest ecosystems, climate change is making forest fires worse, and vice-versa — creating a vicious "climate-fire feedback loop."

It works like this: Rising greenhouse gas (GHG) emissions lead to hotter, drier conditions. This makes it easier for fires to spark and grow. Worsening fires release larger amounts of stored carbon into the atmosphere as trees and plants burn — further accelerating climate change and perpetuating the cycle.

Here's a closer look at what's driving this feedback loop and how it's currently playing out in the world's forests.

1) Climate Change Is Creating Hotter, Drier Conditions.

The world is getting hotter: 2023 and 2024 were each the warmest year on record. In fact, the 10 hottest years on record all occurred in the last decade. Extreme heat waves are now 5 times more likely than they were 150 years ago, while droughts are more frequent and severe.

Rising GHG emissions, principally from the burning of fossil fuels, are unequivocally responsible for these changes in our climate.

2) Hotter, Drier Forests Are More Fire-Prone.

Rising temperatures are directly affecting forests worldwide. And nearly half of all forested areas globally are now more vulnerable to drought than they were before the turn of the century.

These hotter, drier conditions make forests more flammable. When a fire ignites — typically from human accidents or negligence, lightning, or intentional burning to clear land for agriculture — dried-out vegetation acts like kindling, lighting up and spreading quickly.

This has contributed to rising fire activity globally — both in ecosystems that are adapted to fires (like temperate and boreal forests) and in areas that have historically been less susceptible to them (namely, tropical forests). In fact, the majority of forests are now twice as likely to experience extreme "fire weather."

Looking ahead, climate models project that areas with fire-prone conditions could rise 111% by the end of this century in boreal regions like Canada and Russia, which already account for more than 60% of all forest fires. Temperate forests, like those in Europe and the U.S., could see a 25% increase.

Warming temperatures year-round also mean that fire seasons could start earlier and end later in the year. Weather data shows that fire seasons in parts of the western U.S., Mexico, Brazil and East Africa are more than a month longer than they were 35 years ago.

3) Fires Are Getting Bigger and More Destructive.

Climate change isn't just increasing the frequency and intensity of extreme fires; those fires are burning larger areas, too. The latest data, covering 2001-2024, shows that forest fires now burn more than twice as much tree cover each year as they did at the start of the century.

For example, Canada saw its worst fire season on record in 2023, losing 7.76 million hectares of tree cover — an area larger than Panama. Studies have attributed rising fire activity in eastern Canada to an increase in temperature and decrease in humidity, both of which are driven by human-induced climate change. This is part of a larger pattern unfolding across northern boreal forests.

South America saw record-breaking fires across Brazil, Bolivia and Peru in 2024. Large swaths of the Amazon rainforest caught fire and burned. The fires were attributed to high temperatures and persistent drought fueled by El Niño, building upon a longer trend of prolonged, more extreme droughts that are increasing fire severity in the Amazon.

4) More Fires Release More Emissions, Completing the Loop.

When forests burn, they release carbon stored in the trunks, branches and leaves of trees, as well as carbon stored underground in the soil. Forest fires released more than 4 billion tons of GHGs in both 2023 and 2024. That's 2.5 times more than they emit in an average year — and higher than annual emissions from India, the world's third-biggest climate polluter.

At the same time, forests aren't recovering from fires the way they used to. Native tree species essential to boreal fire cycles are losing their resiliency to fire, putting a greater imbalance between how much carbon they absorb and emit. If extreme fires continue to recur faster than recovery times, forests as a whole may be on the brink of flipping from a net carbon sink to a net carbon source.

The rise in fire-driven emissions and loss of forest carbon contributes to rising temperatures — restarting the climate-fire feedback loop.

Stopping the Cycle

This is a difficult cycle to break: A tiny spark has the potential to transform into a raging fire, exacerbating climate change and making future fires more likely.

Tackling rising temperatures must be a priority. Without meaningful action to reduce GHG emissions, the conditions that allow destructive fires to thrive will become more common and harder to manage — and people and forests will pay the price.

In the meantime, strong investment in fire management and prevention is essential to reduce risk and protect lives and ecosystems. Although strategies vary by forest type and region, fire prevention is often far more cost-effective than response. Fuel reduction, early warning systems and improving response capacity all help. So does supporting Indigenous Peoples and local communities, whose traditional fire knowledge and use of controlled burns play a vital role in maintaining fire-resilient landscapes.

Now is the time to prioritize climate action and fire prevention as essential tools for safeguarding communities and ecosystems. As the impacts of forest fires spread, it is more important than ever to break the climate-fire feedback loop.