A dangerous wave of wildfires is spreading across the tropics, and the Amazon rainforest is now facing a growing crisis. Fueled by severe drought linked to El Niño, fires are sweeping through parts of Brazil, filling cities with smoke and threatening forests already damaged by previous fire seasons.
Unlike tornadoes or thunderstorms, which can cause widespread destruction in a matter of minutes, El Niño influences weather patterns over many months. The climate phenomenon can disrupt rainfall across vast regions, creating unusually dry conditions that allow fires to spread rapidly. Scientists warn that the Amazon may be entering the beginning of a prolonged and destructive fire season.
NASA Satellites Detect Surging Amazon Wildfires
Beginning in September 2026, satellite observations revealed a sharp increase in fires and smoke emissions across the central and eastern Amazon. The growing activity appeared in several monitoring systems, including NASA’s Fire Information for Resource Management System (FIRMS), the Global Fire Emissions Database (GFED), and NASA Worldview.
The affected area extends from the forests surrounding Manaus and Santarém, two major commercial and transportation hubs in Brazil, eastward toward the mouth of the Amazon River. As the dry conditions tightened their grip on the region, local ecosystems and human populations alike began to feel the immediate impacts of the unfolding environmental strain.
On October 12, 2026, the MODIS (Moderate Resolution Imaging Spectroradiometer) instrument aboard NASA’s Aqua satellite captured a striking image showing enormous plumes of smoke rising from fires on both sides of the Amazon River. The sheer scale of the smoke emissions underscored the unprecedented nature of the drought conditions gripping the basin.
At the time, thick smoke had engulfed Manaus, the capital of Brazil’s Amazonas state. City officials reported dangerously polluted air, with concentrations of fine particulate matter (PM2.5) exceeding 135 micrograms per cubic meter. These microscopic particles can penetrate deep into the lungs and pose serious health risks to residents. The measurements placed the city’s air quality in the second-worst category of a regional air quality index, forcing local authorities to issue urgent health advisories.
The smoke brought major disruptions to Manaus, which is home to more than 2 million people. Schools shut down, public events were canceled, and children’s sports leagues suspended activities as authorities warned residents about hazardous conditions, according to news reports. Vulnerable populations, including the elderly and young children, were particularly impacted by the toxic haze that blanketed the urban center.
El Niño Is Triggering a Wildfire Domino Effect
According to Douglas Morton, an Earth system scientist at NASA’s Goddard Space Flight Center, the fires surrounding Manaus and Santarém are part of a much larger global pattern.
Morton describes the phenomenon as a "cascade" of tropical fires driven by rainfall disruptions associated with El Niño. The sequence typically begins near the equator, where drought helps ignite peat fires in Indonesia. These fires burn through carbon-rich organic material in the soil, releasing massive amounts of greenhouse gases into the atmosphere. As dry conditions develop elsewhere around the globe, fire activity subsequently intensifies in the central and eastern Amazon.
This pattern is not entirely new to climate scientists. Following the devastating 2015-2016 El Niño event, Morton worked with researchers from the University of California, Irvine; Vrije Universiteit Amsterdam; and the University of Maryland to examine how tropical fires followed shifting rainfall patterns. Their findings were eventually published in a 2017 study, and researchers observed a very similar sequence unfold during the 2023 El Niño cycle.
Now, the 2026 El Niño appears to be producing the exact same sequential progression across the globe’s tropical forests.
Indonesia has already experienced months of ongoing drought, thick smoke, and destructive fires beginning as early as August. During October, these fires destroyed hundreds of homes, while dense smoke covered entire islands on most days of the week, disrupting daily life and transportation networks.
"Now, in the Amazon, we’re seeing the second domino in the cascade fall," Morton said, referring to the alarming and increasing number of fires spreading across the Brazilian states of Pará and Amazonas.
Scientists Warn More Fires Could Spread Into 2027
The current surge of fires may be only one stage of a much longer and more punishing fire season.
Morton and his colleagues anticipate that fire activity will continue to expand northward during November and December 2026. The regions currently at the highest risk include the Brazilian states of Roraima and Amapá, northern Pará, and portions of neighboring Venezuela, Guyana, and Suriname, where dry conditions are expected to peak in the coming weeks.
The pattern is then expected to shift southward as the seasons change. By August and September 2027, drought conditions and wildfire danger could reach their absolute highest levels in the southern Amazon regions of Brazil, as well as parts of neighboring Paraguay.
One particularly troubling aspect of the current crisis is that many of the forests currently threatened have burned before in recent memory.
"It’s so striking — and frustrating — that this is happening all over again," said Morton, noting that forests affected by the severe 2015 and 2023 El Niño events are once again catching fire and suffering renewed degradation.
Wildfires are exceptionally destructive in tropical rainforests because most of the plants and animals living within these complex ecosystems have not evolved to withstand frequent burning. Unlike temperate ecosystems or grasslands where fire is a regular and natural part of the ecological cycle, Amazon forests can suffer severe, systemic, and lasting damage when flames move through their understories.
Previous fires have also left parts of the forest significantly more vulnerable to future blazes. Trees that were partially burned or stressed during earlier events may be weakened or structurally damaged, making the remaining vegetation much more susceptible to ignition. Morton warned that some of the current blazes could therefore burn more intensely and consume biomass faster than previous fires.
He expects the fires near major hubs like Manaus and Santarém to persist until seasonal rains finally return to the region, which is historically expected around December 2026 or January 2027.
However, communities in regions farther north and south still have a critical, albeit shrinking, window of opportunity to reduce the danger before local conditions deteriorate further.
"Given the intensity of this El Niño, this really is the year for people to avoid burning at all costs," Morton said, emphasizing the urgent need for preventative local action.
Extreme Drought Turns Human-Started Fires Into Wildfires
Although the Amazon is currently experiencing a severe and widespread fire emergency, lightning is rarely responsible for igniting fires in Brazil’s dense rainforest.
The region is normally so naturally wet and humid that lightning causes less than 1 percent of fires, according to Morton. This stark reality means that nearly all of the fires currently spreading wildly through the Brazilian Amazon originated directly from human activity.
What makes 2026 particularly dangerous, however, is the extreme severity of the ongoing drought, which has removed the natural safety margins that usually keep managed fires under control.
Brazil’s National Institute of Meteorology reported that rainfall in Manaus was an astounding 95 percent below normal levels in August, followed by a decline of 60 percent below normal in September.
These exceptionally dry conditions have effectively transformed fires that might otherwise have remained safely confined to managed agricultural areas into fast-moving, uncontrolled wildfires.
Morton explained that many of the larger blazes currently ravaging the landscape began as deliberately set fires used for routine land management practices. These include clearing shrubs from cattle grazing land or getting rid of crop residue from agricultural fields after a harvest. Once the flames escaped their intended boundaries due to the parched conditions, they spread rapidly into the rainforest’s vulnerable understory—the dense layer of vegetation growing beneath the towering canopy trees.
Satellite analysis currently suggests that approximately 50 to 70 uncontrolled fires are actively burning in the Santarém area alone, according to Shane Coffield, an assistant research scientist at the University of Maryland who works at NASA Goddard.
NASA Uncovers Hidden Fires That Satellites Are Missing
Despite the advanced capabilities of modern space-borne technology, the actual number of Amazon wildfires may be substantially higher than standard satellite monitoring systems indicate.
As part of a ongoing NASA Earth Action project, Coffield is studying detailed observations collected by VIIRS (Visible Infrared Imaging Radiometer Suite), a specialized satellite instrument capable of detecting thermal heat signatures associated with active fires on the Earth’s surface.
His primary goal is to identify hidden fires that fail to meet the strict detection thresholds and requirements used in official FIRMS data products, which often miss smaller or obscured burning events.
These additional detections, known to researchers as "candidate fires," could eventually help scientists develop a much more complete and accurate picture of the true scale of wildfire activity across the basin. Coffield plans to provide their exact locations to MapBiomas, a collaborative network of universities, nongovernmental organizations, and technology companies that tracks fires and changes in land use throughout the Amazon.
The initial findings from this targeted research suggest that conventional monitoring methods are overlooking a significant number of active blazes.
"For the area around Santarém, we’ve identified about 40 percent more fires than you’ll see in active fire counts from FIRMS," Coffield noted.
Detecting fires beneath a thick rainforest canopy can be surprisingly difficult, even with the most sophisticated instruments currently in orbit. Satellite sensors identify wildfires by measuring thermal infrared radiation, which reveals the intense heat generated by burning vegetation on the ground.
However, thick smoke, persistent cloud cover, and dense tree canopies can severely interfere with those measurements. Fires that burn slowly and creep through the understory are particularly difficult to detect from space because the lush vegetation above them can effectively conceal their heat signatures from orbiting instruments.
As a result, official satellite fire counts may sometimes register a decline even when extensive burning and ecological destruction continue unabated on the forest floor.
"On some of the smokiest days, we have very few detections from MODIS and VIIRS, and we know that isn’t right," Coffield said.
By identifying the fires that existing monitoring systems consistently overlook, NASA researchers hope to provide scientists, policymakers, and local land managers with a more accurate understanding of the unprecedented threats facing the Amazon as the El Niño-driven fire season continues to unfold.
