The Amazon rainforest fires are overwhelmingly caused by people, not natural events like lightning strikes. Farmers, ranchers, loggers, and miners deliberately set fires to clear land, and those fires escape into surrounding forest, especially during hot, dry conditions that climate change has made more frequent and severe. In 2024 alone, 3.3 million hectares of Amazon forest burned, nine times the average over the previous two decades.
Land Clearing Is the Primary Ignition Source
Most Amazon fires start with a match, not a lightning bolt. The dominant cause is slash-and-burn land clearing: cutting down a section of forest, letting it dry, then setting it on fire to make way for cattle pasture or crops. Small-scale farmers and Indigenous communities have used controlled burns for centuries as a land preparation technique, and many authorities still tolerate the practice. But the scale has changed dramatically. Industrial-level deforestation driven by mining, cattle ranching, and large-scale agriculture has transformed what was once a manageable tradition into a serious threat.
The specific economic driver varies by country. In Brazil, cattle ranching is the single largest cause of deforestation. Soy farming follows close behind. In other parts of the Amazon basin, palm oil cultivation and mining play bigger roles. What ties them together is the same basic sequence: cut the trees, burn the land, convert it to production.
The critical problem is containment. When fires are set during drought conditions, they don’t stay where they’re started. Flames jump from cleared land into neighboring forest that has dried out enough to burn. During the 2015-16 El Niño, fires that escaped agricultural areas burned one million hectares of forest in a single dry season.
Global Demand Fuels the Burning
The fires aren’t just a local issue. They’re linked to international markets for beef and soybeans. Research has shown that Amazon cattle and soy industries respond directly to economic signals from around the world. When China’s economic growth surged and mad cow disease outbreaks disrupted beef supplies elsewhere, deforestation rates in the Amazon hit historic highs between 2002 and 2004. When commodity prices rise, the financial incentive to clear more forest rises with them.
This creates a dynamic where consumer demand thousands of miles away translates into fires deep in the Amazon. Ranchers and soy farmers see cleared land as an investment, and global markets set the price. Some producers have started recognizing that sustainable practices could improve their market access, but the economic pressure to expand remains powerful.
Climate Change Has Made the Forest Flammable
The Amazon used to be too wet to burn in most places. That’s changing. As global temperatures have risen, the Amazon region has become hotter, drier, and more vulnerable to prolonged droughts. The number of “wildfire danger days,” when conditions are hot and dry enough for fires to spread, has increased even in the deep interior of the forest where burning was previously almost impossible.
El Niño cycles intensify this effect. During the 2015-16 El Niño, temperatures in parts of the Amazon ran 1.5 to 2°C higher than in previous El Niño events. The dry season stretched two months longer than usual, and the measure of dry-season intensity hit its highest level in nearly two decades. Those conditions turned forest that normally acts as a firebreak into fuel. A climate-driven drought spanning 2023 and 2024 was so severe it dropped water levels to the point of isolating riverside communities entirely.
The result is a “triangle of fire” where high temperatures, low humidity, and available fuel all reinforce each other. Climate change is stretching the dangerous dry season longer each year, meaning any ignition source, whether legal or illegal, carries greater risk of becoming an uncontrollable wildfire.
Illegal Fires Target Protected Land
Many Amazon fires aren’t just reckless. They’re criminal. Fires regularly encroach on protected reserves and Indigenous territories, sometimes spreading accidentally from nearby clearing operations, but often set deliberately as land grabs. Indigenous communities in Brazil have reported finding bottles of gasoline and matches at fire sites on their land. Their territory is supposed to be protected under the Brazilian constitution, but enforcement has been inconsistent.
Indigenous chief Zé Bajaga has described the majority of these fires as arson, set by people looking to exploit land for logging, mining, or conversion to pasture. For Indigenous communities, these fires don’t just destroy forest. They threaten water sources, food supplies, and the physical safety of people living in the path of the flames.
Enforcement Collapsed at a Critical Moment
Brazil’s track record on deforestation enforcement tells a revealing story. In 2004, when deforestation hit 27,800 square kilometers, the government launched an ambitious prevention plan. Over the next 14 years, authorities issued 43,600 land-use embargoes and 84,300 fines, targeting 3.3 million hectares and totaling $9.3 billion in penalties. The approach worked: deforestation rates dropped substantially.
Then enforcement fell apart. Starting in 2019, the number of embargoes and asset confiscations dropped by 59% and 55% respectively. A new system of “conciliation hearings” and centralized legal processes reduced the number of actual judgments by 85% and cut the ratio of lawsuits resulting in paid fines from 17% to just 5%. Coordination of field operations shifted from environmental agencies to the military, which lacked the specialized expertise. Spending went up while results went down, a massive efficiency loss.
By 2021, Amazon deforestation had risen to 13,000 square kilometers, the highest level since 2007. Forest fires devastated vast areas across both the Amazon and the Pantanal wetlands. The prevention plan was relaunched in 2023 after a three-year gap, but the damage from the enforcement vacuum was already done. Research has consistently shown that deforestation rates respond more to political and economic context than to environmental policy on paper.
The Scale Keeps Growing
The numbers from recent years are stark. In September 2024, satellites detected more than 340,000 fire hotspots across South America, concentrated in Bolivia, Brazil, Paraguay, and Peru. That represented a 15 to 20% increase compared to the 2012-2024 average. The Pantanal, a massive wetland bordering the Amazon, saw a 3,910% increase in fires in August 2024 compared to August 2023.
The 3.3 million hectares of Amazon forest that burned in 2024 was the largest area affected since 2021. According to a study published in Biogeosciences by the EU’s Joint Research Centre, this produced record carbon dioxide emissions, which feeds the cycle further. More CO₂ means more warming, which means drier conditions, which means more fire. Scientists have warned that extreme droughts and forest fires will become more frequent across much of the Amazon, potentially triggering large-scale forest dieback where the ecosystem can no longer sustain itself as rainforest.
Each fire season degrades the forest’s ability to resist the next one. Burned forest holds less moisture, supports fewer trees, and becomes more vulnerable to future ignition. The combination of deliberate clearing, weakened enforcement, and a warming climate has created conditions where the Amazon is burning at a pace that far exceeds its ability to recover.