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Amazon deforestation and development heighten Amazon fire risk: study

  • The current fires burning in the Brazilian Amazon are helping confirm the findings of a new study published this July which shows a major connection between land use and fire incidence — with deforestation and development contributing more to fire occurrence than climate change.
  • New research shows that unrestrained deforestation, along with the construction of new highways, could expand wildfire risk in the Amazon by more than 70 percent by 2100, even inside protected areas and indigenous reserves that have relatively intact forests.
  • Scientist suggest that efforts to improve sustainable land management and reduce future deforestation and development could offer the best defenses against the escalating threat wildfires pose due to the increased heat and drought brought by escalating climate change.
Forest fires burn out of control in the municipality of Colniza, Mato Grosso state, Brazil in 2019. Image by Victor Moriyama / Greenpeace.

As of August 24, there were 41,858 fires reported this year in the Brazilian Amazon — the highest number since 2010, when 58,476 were recorded by that date. Likewise, the U.S. space agency NASA has shown this to be the most active fire year for the region since 2010.

However, there is a major difference between 2010 and 2019. Brazil was gripped by one of the worst droughts it had seen in decades in 2010, whereas rainfall is only slightly lower than normal in 2019. So what caused this year’s non-drought related spike in destructive fires?

Scientists think they may have the answer, and point to a massive uptick in deforestation between 2010 and today as a root cause.

Over the last few months alone, deforestation has shot up alarmingly, with the rate in June 2019 running 88 percent higher than during the corresponding month in 2018, according to Brazil’s National Institute for Space Research (INPE). And with the rate soaring again in July 2019 to 278 percent , as compared with the same month a year ago, according to the Amazon Environmental Research Institute (IPAM), A Brazilian NGO.

INPE reported an increase in burn scars in the Amazon, rising from 794 square kilometers last August to 1,259 square kilometers for the first 26 days of last month. For the year, INPE has recorded 46,825 hotspots in Amazonia, more than twice the number of a year ago.

A new study published this July in the journal Global Change Biology, and conducted by INPE and Brazil’s Centre for Disaster Research and Monitoring (CEMADEN), confirms that if this rising deforestation trend continues, then land-use — and especially deforestation — more than climate change and drought will likely be the major driver of increases in Amazon wildfires through 2100.

“Most of the current fires are related to the deforestation process,” Luiz Aragão, professor of geography and earth sciences at the University of Exeter and a study co-author told Mongabay. “If you look at the 10 municipalities with the highest deforestation rates, they are also the ones with the highest rate of fires,” he said, quoting a recent IPAM report showing that most of the 2019 increase in fires is concentrated in municipalities with higher deforestation rates.

Short-term and long-term deforestation trends in the Brazilian Amazon. Annual data is based on INPE’s high resolution satellite analysis, while short-term data is based on INPE’s deforestation monitoring system DETER. * 2019 annual data should be released in November or December 2019.

The link between deforestation and fire risk

It is well understood that warming temperatures, recurring prolonged drought, Amazon road development (which fragments and offers greater access to forests), and deforestation from land use change (especially the ongoing conversion of rainforests to cattle pasture and cropland), all contribute significantly to the increasing incidence of wildfires.

But the big debate has been, precisely how much does each factor contribute to an uptick in fires?

To find an answer, the research team modeled the different effects of land use and climate change on the Brazilian Amazon rainforest. They found that land use change alone could expand the areas at risk from wildfire by more than 70 per cent by the year 2100, even inside protected areas and indigenous reserves that have relatively intact forests.

“Our paper shows that land use governance is decisive to mitigating the effects of climate change on fire probability,” said study lead author Marisa Gesteira Fonseca, a postdoctoral researcher at INPE, the agency currently responsible for the satellite monitoring of Brazil’s deforestation. “Even under the worst climate scenarios it is still important to avoid deforestation in the Amazon” in order to reduce fire risk.

Looking at the probability of fire occurrence between 2041-2070, and 2071-2100 under varying land use scenarios, the research team was able to determine to what extent land use change versus climate change would effect what part of the Amazon, and even estimate how many wildfires might occur under various scenarios.

“This is a significant improvement on previous papers estimating fire risk, which were much more simplistic in their modeling and assumptions about governance,” said Jos Barlow, a professor of conservation science at Lancaster University, who wasn’t involved in the research.

Aragão said that the extreme intensity of the 2019 Amazon fires also helped validate the model used in the study. “If we look at the climate, we see that this year there is no sign of [severe] drought, even though we have this massive increase in fire,” but there is a significant rise in deforestation. “It really shows us that fires in the region are affected by human activities on the ground and for mitigating them, we really need to act on these [land use] players.”

Cumulative fire hotspots in the Brazilian Amazon thru August from 1999 to 2019. Image by Mongabay, data courtesy of INPE.

Wildfires and climate change in the Amazon

While deforestation is already recognized as an important driver of carbon emissions worldwide, wildfires are becoming an increasingly pernicious threat, even in places like the Amazon that were until recent years largely immune to widespread wildfires.

Despite a recent significant uptick in deforestation, overall Brazil has seen a 75 percent decline in deforestation rates since 2004, however the rate of wildfires has increased.

“What we are observing is that wildfires are becoming disconnected from the deforestation process,” said Aragão. “That means that the fire is not necessarily coming from areas that are being deforested.”

A study published last year by Aragão and colleagues in the journal Nature Communications found that especially in years with lower-than-average rainfall, emissions from drought-induced fires unrelated to deforestation increasingly play a much larger role than those from deforestation, causing areas previously barely affected by fires to burn. The researchers concluded that, “in a hotter and drier future, large swaths of the Amazon, distant from the main deforestation epicenters, may burn.”

Importantly, the United Nations Intergovernmental Panel on Climate Change (IPCC) does not require that carbon emissions resulting from wildfires be included in a nation’s total annual greenhouse gas emissions — a significant omission considering that fires release massive amounts of carbon that would otherwise be sequestered in living, growing trees. This UN greenhouse gas source reporting loophole is especially worrisome considering the importance of the Amazon in calculating our global carbon budget — how much carbon we can “spend” before pushing past the 2 degree Celsius upper limit set by the IPCC, above which catastrophic climate change could occur.

Counting forest emissions accurately is also critical to Brazil keeping its Paris Climate Agreement commitment of reducing its emissions to 37 percent below 2005 levels by 2025.

In an article last year on the Conversation website, a website for academics to share research and news analysis, Barlow argued that as wildfires in once largely fire-proof rainforests like the Amazon increase, nations should prepare urgent actions aimed at mitigating the potential increase of fire emissions, in response to the intensification of droughts in tropical ecosystems.

Aerial view of a large wildfire in the city of Candeiras do Jamari in the state of Rondônia. Image by Victor Moriyama / Greenpeace.

Linking climate change and land-use

The recent study contributes to a growing field of research looking at the direct and indirect connection between climate change and land use policies. Globally, agriculture, deforestation, and other land use practices are responsible for roughly a quarter of all human-caused greenhouse gas emissions. Conversely, various reports show the tremendous potential that intact tropical forests have for combatting global warming.

All of this recent research combines to make the finding of the new study, which show increased incidences of wildfire even in protected areas and indigenous reserves, more alarming.

“We expected that in the worst case scenario we would find an increase [in wildfire incidence]. But the coincidence of areas of high change with indigenous lands and protected area was much larger than we thought it would be,” said Gesteira Fonseca.

If deforestation and development isn’t controlled, then more than 1 million square kilometers (386,102 square miles) of indigenous lands and protected areas in the Brazilian Amazon could be subject to an increased likelihood of occurrence of wildfires by 2100, threatening both ecosystems and human populations in these areas.

For Barlow, the results highlight a key issue that is now being recognized across biomes: that maintaining intact, and better yet, near-pristine ecosystems, is essential to help avoid the worst outcomes threatened by climate change. “This in itself is not new,” said Barlow, “but this paper provides a powerful and convincing set of evidence that supports it in the Amazonian context.”

Even under more optimistic climate change scenarios, the socioeconomic, institutional, and environmental dynamics related to increased development and deforestation of the Amazon would dramatically increase fire probability, said the researchers.

For Gesteira Fonseca and Aragão, even though the results show a higher fire incidence, the fact that land use change plays such an outsized role is in some ways a silver bullet: if we can change and improve land use practices in the Amazon, reducing deforestation and controlling development, we can also reduce the incidence of fires. “If the main variable were climate change,” said Aragão, “the scale of making a difference would be much more long term.”


Fonseca, Marisa Gesteira, et al. “Effects of climate and land‐use change scenarios on fire probability during the 21st century in the Brazilian Amazon.” Global change biology 25.9 (2019): 2931-2946.

Banner image caption: Forest fires burn out of control in the municipality of Colniza, Mato Grosso state, Brazil. Image by Victor Moriyama / Greenpeace.

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