case study of amazon forest fire

Explainer: Causes and consequences of Amazon fires and deforestation

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WHAT CAUSES THE FIRES?

Why are brazil's fires so bad at this time of year, is climate change affecting amazon forest fires, have brazil's fires been worse than usual in recent years, how much worse is forest loss since 2019.

WILL THIS YEAR'S FIRE SEASON BE DIFFERENT?

Are the amazon fires contributing to climate change.

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Reporting by Jake Spring in Sao Paulo and Gloria Dickie in London; Editing by Katy Daigle

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Jake Spring reports primarily on forests, climate diplomacy, carbon markets and climate science. Based in Brazil, his investigative reporting on destruction of the Amazon rainforest under ex-President Jair Bolsonaro won 2021 Best Reporting in Latin America from the Overseas Press Club of America (https://opcofamerica.org/Awardarchive/the-robert-spiers-benjamin-award-2021/). His beat reporting on Brazil’s environmental destruction won a Covering Climate Now award and was honored by the Society of Environmental Journalists. He joined Reuters in 2014 in China, where he previously worked as editor-in-chief of China Economic Review. He is fluent in Mandarin Chinese and Brazilian Portuguese.

Gloria Dickie reports on climate and environmental issues for Reuters. She is based in London. Her interests include biodiversity loss, Arctic science, the cryosphere, international climate diplomacy, climate change and public health, and human-wildlife conflict. She previously worked as a freelance environmental journalist for 7 years, writing for publications such as the New York Times, the Guardian, Scientific American, and Wired magazine. Dickie was a 2022 finalist for the Livingston Awards for Young Journalists in the international reporting category for her climate reporting from Svalbard. She is also an author at W.W. Norton.

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• Environment

Everything you need to know about the fires in the Amazon

Why are the fires burning and why is it such a big deal.

By Justine Calma , a senior science reporter covering climate change, clean energy, and environmental justice with more than a decade of experience. She is also the host of Hell or High Water: When Disaster Hits Home, a podcast from Vox Media and Audible Originals.

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Record-breaking fires are ripping through the Amazon — an ecosystem on which the whole world depends. The Verge will update this page with news and analysis on the fires and the effects that could linger once the ash settles.

Table of Contents: 

Why is the Amazon burning?

Why is this a big deal?

Why is this a hot topic politically?

• How are the fires being fought?

An unprecedented number of fires raged throughout Brazil in 2019, intensifying in August. That month, the country’s National Institute for Space Research (INPE) reported that there were more than 80,000 fires, the most that it had ever recorded. It was a nearly 80 percent jump compared to the number of fires the country experienced over the same time period in 2018. More than half of those fires took place in the Amazon. 

The number of blazes decreased in September , after president Jair Bolsonaro bowed to mounting pressure to address the flames and announced a 60-day ban on setting fires to clear land. Some exceptions were made for indigenous peoples who practice subsistence agriculture and those who’ve received clearance by environmental authorities to use controlled burning to prevent larger fires.

“There is no doubt that this rise in fire activity is associated with a sharp rise in deforestation”

“These are intentional fires to clear the forest,” Cathelijne Stoof, coordinator of the Fire Center at Wageningen University (WUR) in the Netherlands, tells The Verge . “People want to get rid of the forest to make agricultural land, for people to eat meat.” The INPE found that deforestation in Brazil’s Amazon hit an 11-year high in 2019.

“There is no doubt that this rise in fire activity is associated with a sharp rise in deforestation,” Paulo Artaxo, an atmospheric physicist at the University of São Paulo, told Science Magazine . He explained that the fires are expanding along the borders of new agricultural development, which is what’s often seen in fires related to forest clearing. 

President Jair Bolsonaro’s administration, which had pledged to open up the Amazon to more development, has sought to shift attention away from deforestation. Bolsonaro initially pointed a finger at NGOs opposing his policies for allegedly intentionally setting fires in protest, without giving any evidence to back his claim. In August, he fired the director of the National Institute for Space Research over a dispute over data it released showing the sharp uptick in deforestation that’s taken place since Bolsonaro took office. On August 20th, Brazil’s Minister of the Environment Ricardo Salles tweeted that dry weather, wind, and heat caused the fires to spread so widely. But even during the dry season, large fires aren’t a natural phenomenon in the Amazon’s tropical ecosystem. 

Everyone on the planet benefits from the health of the Amazon. As its trees take in carbon dioxide and release oxygen, the Amazon plays a huge role in pulling planet-warming greenhouse gases out of the atmosphere. Without it, climate change speeds up. But as the world’s largest rainforest is eaten away by logging, mining, and agribusiness, it may not be able to provide the same buffer.

“The Amazon was buying you some time that it is not going to buy anymore,” Carlos Quesada, a scientist at Brazil’s National Institute for Amazonian Research, told Public Radio International in 2018. Scientists warn that the rainforest could reach a tipping point , turning into something more like a savanna when it can no longer sustain itself as a rainforest. That would mean it’s not able to soak up nearly as much carbon as it does now.  And if the Amazon as we know it dies, it wouldn’t go quietly. As the trees and plants perish, they would release billions of tons of carbon that has been stored for decades — making it nearly impossible to escape a climate catastrophe. 

Everyone on the planet benefits from the health of the Amazon

Of course, those nearest to the fires will bear the most immediate effects. Smoke from the fires got so bad, it seemed to turn day into night in São Paulo on August 20th. Residents say the air quality is still making it difficult to breathe. On top of that, a massive global study on air pollution found that among the two dozen countries it observed, Brazil showed one of the sharpest increases in mortality rates whenever there’s more soot in the air.

And because fire isn’t a natural phenomenon in the region, it can have outsized impacts on local plants and animals. One in ten of all animal species on Earth call the Amazon home, and experts expect that they will be dramatically affected by the fires in the short term . In the Amazon, plants and animals are “exceptionally sensitive” to fire, Jos Barlow, a professor of conservation science at Lancaster University in the UK, said to The Verge in an email. According to Barlow, even low-intensity fires with flames just 30 centimeters tall can kill up to half of the trees burned in a tropical rainforest. 

When Jair Bolsonaro was campaigning for office as a far-right candidate, he called for setting aside less land in the Amazon for indigenous tribes and preservation, and instead making it easier for industry to come into the rainforest. Since his election in October 2018, Bolsonaro put the Ministry of Agriculture in charge of the demarcation of indigenous territories instead of the Justice Ministry, essentially “letting the fox take over the chicken coop,” according to one lawmaker . His policies have been politically popular among industry and agricultural interests in Brazil, even as they’ve been condemned by Brazilian environmental groups and opposition lawmakers. Hundreds of indigenous women stormed the country’s capital on August 13th to protest Bolsonaro’s environmental rollbacks and encroachment of development on indigenous lands. The hashtag #PrayforAmazonia blew up on Twitter. 

About 60 percent of the Amazon can be found within Brazil’s borders, which gives the nation a massive amount of influence over the region. Not surprisingly, the fires have called international attention to the plight of the Amazon and have turned up the heat on Bolsonaro’s environmental policies.  

French President Emmanuel Macron took to Twitter to call for action, pushing for emergency international talks on the Amazon at the G7 summit. On August 26th, the world’s seven largest economies offered Brazil more than $22 million in aid to help it get the fires under control. Bolsonaro promptly turned down the money, accusing Macron on Twitter of treating Brazil like a colony. Some in Brazil, including Bolsonaro, see the international aid as an attack on Brazil’s sovereignty , and its right to decide how to manage the land within its borders. 

“Letting the fox take over the chicken coop”

President Donald Trump, on the other hand, congratulated Bolsonaro on his handling of the fires. “He is working very hard on the Amazon fires and in all respects doing a great job for the people of Brazil,” he tweeted on the 27th.      

Bolsonaro has since said that he’ll reconsider the deal, as long as Macron takes back his “ insults ” and Brazil has control over how the money is spent. On the 27th, Bolsonaro accepted $12.2 million in aid from the UK.

How are the fires being fought?  

After weeks of international and internal pressure, Bolsonaro deployed the military to help battle the fires on August 24, sending 44,000 troops to six states. Reuters reported the next day that warplanes were dousing flames.

“It’s a complex operation. We have a lot of challenges,” Paulo Barroso tells The Verge. Barroso is the chairman of the national forest fire management committee of the National League of Military Firefighters Corps in Brazil. He has spent three decades fighting fires in Mato Grosso, one of the regions most affected by the ongoing fires. According to Barroso, more than 10,400 firefighters are spread thin across 5.5 million square kilometers in the Amazon and “hotspots” break out in the locations they’re unable to cover. 

“We don’t have an adequate structure to prevent, to control, and to fight the forest fires”

Barroso contends that they need more equipment and infrastructure to adequately battle the flames. There are 778 municipalities throughout the Amazon, but according to Barroso, only 110 of those have fire departments. “We don’t have an adequate structure to prevent, to control, and to fight the forest fires,” Barroso says. He wants to establish a forest fire protection system in the Amazon that brings together government entities, indigenous peoples, local communities, the military, large companies, NGOs, and education and research centers. “We have to integrate everybody,” Barroso says, adding, “we need money to do this, we have to receive a great investment.”

Barroso and other experts agree that it’s important to look ahead to prevent fires like we’re seeing now. After all, August is just the beginning of Brazil’s largely manmade fire season, when slashing-and-burning in the country peaks and coincides with drier weather. 

Controlled burns are also a popular deforestation technique in other countries where the Amazon is burning, including Bolivia . There, the government brought in a modified Boeing 747 supertanker to douse the flames.  

Using planes to put out wildfires in the Amazon isn’t a typical method of firefighting in tropical forests, and is likely to get expensive, Lancaster University’s Jos Barlow tells The Verge . He says that large-scale fires in areas cleared by deforestation “are best contained with wide firebreaks created with bulldozers — not easy in remote regions.” If the fires enter the forest itself, they require different tactics. “They can normally be contained by clearing narrow fire breaks in the leaf litter and fine fuel,” Barlow says. “But this is labour intensive over large scales, and fires need to be reached soon, before they get too big.”

Fires that have been intentionally set, as we’re seeing in Brazil, can be even more difficult to control compared to a sudden wildland fire. “They’re designed to be deliberately destructive,” says Timothy Ingalsbee, co-founder and executive director of Firefighters United for Safety, Ethics, and Ecology and research associate at the University of Oregon. Slashing before burning produces a lot of very dry, very flammable fuel. And at this scale, Ingalsbee calls the fires “an act of global vandalism.”

Barlow says, “The best fire fighting technique in the Amazon is to prevent them in the first place — by controlling deforestation and managing agricultural activities.”

WUR’s Cathelijne Stoof agrees: “Fighting the fires is of course important now,” she says. “For the longer term, it is way more important to focus on deforestation.”

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A fire burns along the road to Jacunda National Forest, near the city of Porto Velho in the Vila Nova Samuel region, which is part of Brazil’s Amazon.

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Thousands of intentionally set fires push Brazil’s rainforest close to the tipping point

Thousands of fires raging across the Amazon, many deliberately set by loggers, ranchers, and others seeking to clear land, have triggered public outrage in recent weeks and prompted climate experts to warn of a fast-approaching point of no return for the lush jungle that covers more than 2 million square miles and extends into nine countries. The rich rainforest is critical to the Earth’s climate, influencing weather systems, generating oxygen, and absorbing huge amounts of carbon dioxide — the heat-trapping greenhouse gas that contributes to global warming. Harvard’s Brian Farrell , director of the David Rockefeller Center for Latin American Studies , Monique and Philip Lehner Professor for the Study of Latin America, curator of entomology in the Museum of Comparative Zoology,   and professor of biology, has conducted research in the Amazon for decades. He spoke to the Gazette recently about what the fires mean for the future of the planet.

Brian Farrell

GAZETTE:   Can you outline the work you have been doing in the Amazon and whether the fires are affecting it?

FARRELL:   At any one moment, several Organismic and Evolutionary Biology students are conducting their thesis research somewhere in the Amazon. My newly graduated Ph.D. student from Brazil, Bruno de Medeiros, has focused his research on insects associated with pollinating the palms now threatened by the fires. The regions where I conducted research in the 1980s in the Peruvian Amazon are now also under threat.

GAZETTE:   Are these fires a common occurrence? Are they worse this year than in the past, and if so, why?

FARRELL:   Natural fires are not uncommon in any forest ecosystem, but they rarely spread far in the wet forests of the Amazon. The current fires were set deliberately to clear land for cattle ranching and other activities and are more than double this year compared to previous years. While there are no doubt many different people responsible for setting the thousands of fires now burning, they are no doubt all encouraged by a recent weakening of environmental policiesas well as enforcement [in Brazil, where most of the Amazon is situated].

GAZETTE:   What do the fires mean for the biodiversity of the Amazon, and for the indigenous populations living there?

FARRELL:  These widespread fires are driving wildlife away from their habitats and territories, with resulting catastrophic losses. The life and livelihoods of the Yanomami and other indigenous peoples are under threat not seen since the first Europeans entered South America. The fires are spreading like a contagion. The great fear is that the loss of habitat will cross a threshold of no return, a tipping point for transformation of climate cycles that will result in new rainfall patterns. The rainfall cycles in the Amazon depend on transfer of water through rainforest plants to the atmosphere, where it eventually condenses as rain that is delivered over a very broad region, again sustaining rainforest plants as well as much of the continent. If fire removes the plant life responsible for moving water up into the clouds, the land will dry and rainforests will be replaced by grasslands able to withstand the newly arid conditions, which can persist for thousands of years. This has occurred in the Americas and elsewhere in prehistoric times. The economic and ecological consequences for the cities that today depend on these sources of atmospheric water, as well as the natural ecosystems and indigenous peoples they support, will be devastating.

“The very fact that we could reach the tipping point this year should be enough to focus world attention on this crisis, just as if an asteroid were headed toward Earth. Where it lands is not the concern only of the country impacted, but everyone on the planet.”

GAZETTE:   Similarly, what does it mean for the environment when so many trees that help absorb carbon dioxide go up in smoke?

FARRELL:   As the largest rainforest in the world, the Amazon’s storage of carbon is substantial enough to change the world climate if it were released into the atmosphere. This is a risk for the entire planet.

GAZETTE: As you mentioned above, many of the fires have been intentionally set, in large part by Brazilian farmers and ranchers looking to clear their land. Are there ways Brazil’s growing agriculture sector can work to limit its impact on the rainforest?

FARRELL:   The production of cattle and soybeans is one of the least-sustainable and less economically valuable uses of the rainforests. Analyses by the scientists and economists associated with leading climate change authority, scientist Carlos Nobre, clearly show alternative approaches to sustainable extraction that also carry benefits of education and infrastructure development. Through the Amazonian Third Way Initiative, Nobre has shown how the value of pharmaceuticals, nutraceuticals, and other natural plant products yield much greater value per hectare of standing forest than soybeans or cattle production. And these products are sustainably extracted. Think of acai as one example. What is needed, however, is a workforce that is educated to know how to collect and process these products.

GAZETTE:  What responsibility do industrialized nations have to help protect natural resources throughout the developing world? Are we doing enough?

FARRELL:   Conservationists have realized that we must tackle poverty and conservation at the same time while respecting local sovereignty. Many have argued that there are sufficient economic resources as well as practical approaches available to turn things around on both fronts. The limiting factor is the political will to favor long-term solutions over short-term advantages. This is as true here in the U.S.A. as it is elsewhere.

Biologist Brian Farrell warns that humanity should be wary of an environmental tipping point in the immediate future.

Stephanie Mitchell/Harvard file photo

GAZETTE:  Many blame Brazilian President Jair Bolsonaro’s pro-development policies for helping encourage deforestation. Can internal and external pressure change the political situation on the ground?

FARRELL:   It is very clear that sufficiently strong internal protests combined with external sanctions can have effects on government policies anywhere in the world, but these require political will at every level.

GAZETTE:   At the same time, isn’t it true that countries should have the right to govern their natural resources as they see fit, as the U.S. did for generations as it became a global superpower?

FARRELL:  Absolutely. Governments that well represent the will of the people are also members of global economic communities. No country is an island. We in the Americas and around the world share common interests that may help guide us toward a sustainable management of resources. There is the concept of the tragedy of the commons. World climate and world oceans are such commons that may either benefit everyone or decline beyond recovery, depending on how they are managed. Lack of management is the option that results in tragic loss of a common good.

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GAZETTE:  With the Amazon’s dry season set to peak in September, what could happen next?

FARRELL:   That depends on several factors having to do with the somewhat unpredictable pattern of the weather, particularly winds and rain that could either make the situation worse or lessen the effects of the fires. Plus, of course, there is the potential influence of national efforts to quell the fires. But the very fact that we could reach the tipping point  this year  should be enough to focus world attention on this crisis, just as if an asteroid were headed toward Earth. Where it lands is not the concern only of the country impacted, but everyone on the planet. The Amazon fire is like that, a local problem of global significance.

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September 7, 2021 | Combined Reports - UConn Communications

Study Shows the Impacts of Deforestation and Forest Burning on Biodiversity in the Amazon

Since 2001, between 40,000 and 73,400 square miles of Amazon rainforest have been impacted by fires

Ring of fire: Smoke rises through the understory of a forest in the Amazon region. Plants and animals in the Amazonian rainforest evolved largely without fire, so they lack the adaptations necessary to cope with it. (Credit: Paulo Brando)

A new study, co-authored by a team of researchers including UConn Ecology and Evolutionary Biology researcher Cory Merow provides the first quantitative assessment of how environmental policies on deforestation, along with forest fires and drought, have impacted the diversity of plants and animals in the Amazon. The findings were published in the Sept. 1 issue of Nature .

Researchers used records of more than 14,500 plant and vertebrate species to create biodiversity maps of the Amazon region. Overlaying the maps with historical and current observations of forest fires and deforestation over the last two decades allowed the team to quantify the cumulative impacts on the region’s species.

They found that since 2001, between 40,000 and 73,400 square miles of Amazon rainforest have been impacted by fires, affecting 95% of all Amazonian species and as many as 85% of species that are listed as threatened in this region. While forest management policies enacted in Brazil during the mid-2000s slowed the rate of habitat destruction, relaxed enforcement of these policies coinciding with a change in government in 2019 has seemingly begun to reverse this trend, the authors write. With fires impacting 1,640 to 4,000 square miles of forest, 2019 stands out as one of the most extreme years for biodiversity impacts since 2009, when regulations limiting deforestation were enforced.

“Perhaps most compelling is the role that public pressure played in curbing forest loss in 2019,” Merow says. “When the Brazilian government stopped enforced forest regulations in 2019, each month between January and August 2019 was the worse month on record (e.g. comparing January 2019 to previous January’s) for forest loss in the 20-year history of available data. However, based on international pressure, forest regulation resumed in September 2019, and forest loss declined significantly for the rest of the year, resulting in 2019 looking like an average year compared to the 20-year history.  This was big: active media coverage and public support for policy changes were effective at curbing biodiversity loss on a very rapid time scale.”

The findings are especially critical in light of the fact that at no point in time did the Amazon get a break from those increasing impacts, which would have allowed for some recovery, says senior study author Brian Enquist, a professor in UArizona’s Department of Ecology and Evolutionary Biology .

“Even with policies in place, which you can think of as a brake slowing the rate of deforestation, it’s like a car that keeps moving forward, just at a slower speed,” Enquist says. “But in 2019, it’s like the foot was let off the brake, causing it to accelerate again.”

Known mostly for its dense rainforests, the Amazon basin supports around 40% of the world’s remaining tropical forests. It is of global importance as a provider of ecosystem services such as scrubbing and storing carbon from the atmosphere, and it plays a vital role in regulating Earth’s climate. The area also is an enormous reservoir of the planet’s biodiversity, providing habitats for one out of every 10 of the planet’s known species. It has been estimated that in the Amazon, 1,000 tree species can populate an area smaller than a half square mile.

“Fire is not a part of the natural cycle in the rainforest,” says study co-author Crystal N. H. McMichael at the University of Amsterdam. “Native species lack the adaptations that would allow them to cope with it, unlike the forest communities in temperate areas. Repeated burning can cause massive changes in species composition and likely devastating consequences for the entire ecosystem.”

Since the 1960s, the Amazon has lost about 20% of its forest cover to deforestation and fires. While fires and deforestation often go hand in hand, that has not always been the case, Enquist says. As climate change brings more frequent and more severe drought conditions to the region, and fire is often used to clear large areas of rainforest for the agricultural industry, deforestation has spillover effects by increasing the chances of wildfires. Forest loss is predicted reach 21 to 40% by 2050, and such habitat loss will have large impacts on the region’s biodiversity, according to the authors.

“Since the majority of fires in the Amazon are intentionally set by people, preventing them is largely within our control,” says study co-author Patrick Roehrdanz, senior manager of climate change and biodiversity at Conservation International. “One way is to recommit to strong antideforestation policies in Brazil, combined with incentives for a forest economy, and replicate them in other Amazonian countries.”

Policies to protect Amazonian biodiversity should include the formal recognition of Indigenous lands, which encompass more than one-third of the Amazon region, the authors write, pointing to previous research showing that lands owned, used or occupied by Indigenous peoples have less species decline, less pollution and better-managed natural resources.

The authors say their study underscores the dangers of continuing lax policy enforcement. As fires encroach on the heart of the Amazon basin, where biodiversity is greatest, their impacts will have more dire effects, even if the rate of forest burning remains unchanged.

The research was made possible by strategic investment funds allocated by the Arizona Institutes for Resilience at UArizona and the university’s Bridging Biodiversity and Conservation Science group. Additional support came from the National Science Foundation’s Harnessing the Data Revolution program . Data and computation were provided through the Botanical Information and Ecology Network , which is supported by CyVerse , the NSF’s data management platform led by UArizona.

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Hidden Wildfires Taking Big Toll on Amazon Rainforest

A pair of new studies using NASA satellite data shed light on a previously hidden type of Amazon forest wildfire and links between climate conditions and Amazon fire risk.

In the southern Amazon rainforest, fires below the forest treetops, or "understory fires," have been hidden from view from NASA satellites that detect actively burning fires. The new method has now led to the first regional estimate of understory fire damages across the southern Amazon.

"Amazon forests are quite vulnerable to fire, given the frequency of ignitions for deforestation and land management at the forest frontier, but we've never known the regional extent or frequency of these understory fires," said Doug Morton of NASA's Goddard Space Flight Center in Greenbelt, Md., and the study's lead author. The study was published April 22 in Philosophical Transactions of the Royal Society B.

In years with the most understory fire activity, such as 2005, 2007 and 2010, the area of forest affected by understory fires was several times greater than the area of deforestation for expansion of agriculture, according to Morton. The study goes further and fingers climate conditions - not deforestation - as the most important factor in determining fire risk in the Amazon at a regional scale. Uncovering the Story Behind Understory Fires Fires in the Amazon's savanna areas can burn quickly, spreading up to 330 feet (100 meters) per minute. Grasses and shrubs in these ecosystems typically survive low-intensity surface fires. In contrast, understory fires at the frontier and beyond appear "unremarkable when you see them burning," Morton said. Flames reach on average only a few feet high, visible from the air as ribbons of smoke that escape through the canopy. They may burn for weeks at a time, spreading only a few feet (0.5 meters) per minute. Understory fires, however, can damage large areas because Amazon trees are not adapted to fire. The long, slow burn gives way to a creeping death that claims anywhere from 10 to 50 percent of the burn area's trees. Recovery is also a long and slow, but observable, process. To identify understory fires, Morton and colleagues used observations from early in the dry season, from June to August, collected by the Moderate Resolution Imaging Spectroradiometer, or MODIS, instrument on NASA's Terra satellite. They tracked the timing of fire damage and recovery, which varies depending on the type of forest disturbance. Areas of deforestation, for example, show up in satellite imagery as land that continues to lack signs of recovery for at least two consecutive years. Conversely, signs of forest degradation from understory fires, visible in the year after the burn, dissipate quickly as the forest regrows. This pattern of damage and recovery over multiple years provides a fingerprint of understory fire damages in Amazon forests. The study shows that between 1999 and 2010, understory forest fires burned more than 33,000 square miles (85,500 square kilometers), or 2.8 percent of the forest. Results also show no correlation between understory fires and deforestation. As the pressure for clearing led to the highest deforestation rates ever seen from 2003 to 2004, adjacent forests had some of the lowest rates of fires. "You would think that deforestation activity would significantly increase the risk of fires in the adjacent forested area because deforestation fires are massive, towering infernos," Morton said. "You make a bonfire that is a square kilometer in size, throwing ash and live cinders and preheating the adjacent forest. Why didn't we have more understory fires in 2003 and 2004, when deforestation rates were so high?" The researchers point to climate as the reason that fire-driven deforestation didn't burn more surrounding forests in these years. Frequent understory fire activity coincides with low nighttime humidity, as measured by the Atmospheric Infrared Sounder (AIRS) instrument aboard NASA's Aqua satellite. Scientists say the connection points to a strong climate control on Amazon fires. "You can look within an indigenous reserve where there is no deforestation and see enormous understory fires," Morton said. "The human presence at the deforestation frontier leads to a risk of forest fires when climate conditions are suitable for burning, with or without deforestation activity." Ignition could come from cooking, camping, cigarettes, cars, agricultural waste burning or any number of human sources. The new knowledge about the scope of understory fires could have implications for estimates of carbon emissions from disturbed forests. How experts account for those emissions depends on the fate of the forest - how it is disturbed and how it recovers. "We don't yet have a robust estimate of what the net carbon emissions are from understory fires, but widespread damages suggest that they are important source of emissions that we need to consider," Morton said. For now, scientists are looking into the climate mechanisms that, given an ignition source from humans, predispose the southern Amazon to burn. Soil Moisture as a Fire Indicator Already, scientists at the University of California, Irvine, have delved deeper into the climate-fire connection. New research shows that satellite-based measurements of the region's soil moisture could supplement and sharpen fire season forecasts across the southern Amazon. The first forecast in 2012 and new forecast for 2013, led by Jim Randerson at UC Irvine, are based on a model that primarily considers historical fire data from MODIS instruments along with sea surface temperature data from NOAA. Previous research has shown sea surface temperature to be a good indicator of the pending Amazon fire season severity. Now, scientists are interested in fine-tuning the model across smaller geographic regions and finer timescales. Toward that goal, Yang Chen of UC Irvine and colleagues show that water storage estimates from NASA's Gravity Recovery and Climate Experiment, or GRACE, satellites allow monitoring of the evolution of dry conditions during the fire season. Transpiration and evaporation are two ways that water is transported from the ground to the atmosphere. Low water storage in the soil leads to a drier near-ground atmosphere. The result is drier, more flammable vegetation alongside increases in plant litter and fuel availability. Chen's research was published online April 11 in the American Geophysical Union's Journal of Geophysical Research - Biogeosciences. "A severe fire season in the Amazon is often preceded by low water storage in the soil, and this water deficit in the soil can be detected by the satellites several months before the fire season," Chen said. Soil water storage in the southern Amazon in June is a key indicator of fire season severity. "The GRACE measurements provide unique and precise information about land water storage that changes completely the way we can look at fire prediction," said Isabella Velicogna of UC Irvine and NASA's Jet Propulsion Laboratory in Pasadena, Calif., who lead the GRACE analysis. While the water storage estimates are not yet officially part of Randerson and colleagues' forecasts, the study "charts the course forward to leverage GRACE data for operational purposes," Morton said. "The ability to integrate observations from many different NASA instruments is really a hallmark of Earth system science. In this case, the science also has important, practical applications to mitigating the impacts of fires on the Amazon region and global climate." For more information, see: http://www.nasa.gov/topics/earth/features/amazon-fire-risk.html . To read a new assessment by university and NASA researchers of the current outlook for Amazon forest fire risk in the 2013 fire season, visit: http://www.nasa.gov/topics/earth/features/2013-fire-year.html . GRACE is a joint mission with the German Aerospace Center and the German Research Center for Geosciences, in partnership with the University of Texas at Austin. For more about GRACE, visit: http://www.nasa.gov/grace and http://www.csr.utexas.edu/grace . JPL developed the GRACE spacecraft and manages the mission for NASA's Science Mission Directorate, Washington. The California Institute of Technology in Pasadena manages JPL for NASA. Written by Kathryn Hansen NASA's Earth Science News Team

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Case Study: The Amazon Rainforest

The Amazon in context

Tropical rainforests are often considered to be the “cradles of biodiversity.” Though they cover only about 6% of the Earth’s land surface, they are home to over 50% of global biodiversity. Rainforests also take in massive amounts of carbon dioxide and release oxygen through photosynthesis, which has also given them the nickname “lungs of the planet.” They also store very large amounts of carbon, and so cutting and burning their biomass contributes to global climate change. Many modern medicines are derived from rainforest plants, and several very important food crops originated in the rainforest, including bananas, mangos, chocolate, coffee, and sugar cane.

In order to qualify as a tropical rainforest, an area must receive over 250 centimeters of rainfall each year and have an average temperature above 24 degrees centigrade, as well as never experience frosts. The Amazon rainforest in South America is the largest in the world. The second largest is the Congo in central Africa, and other important rainforests can be found in Central America, the Caribbean, and Southeast Asia. Brazil contains about 40% of the world’s remaining tropical rainforest. Its rainforest covers an area of land about 2/3 the size of the continental United States.

There are countless reasons, both anthropocentric and ecocentric, to value rainforests. But they are one of the most threatened types of ecosystems in the world today. It’s somewhat difficult to estimate how quickly rainforests are being cut down, but estimates range from between 50,000 and 170,000 square kilometers per year. Even the most conservative estimates project that if we keep cutting down rainforests as we are today, within about 100 years there will be none left.

How does a rainforest work?

Rainforests are incredibly complex ecosystems, but understanding a few basics about their ecology will help us understand why clear-cutting and fragmentation are such destructive activities for rainforest biodiversity.

High biodiversity in tropical rainforests means that the interrelationships between organisms are very complex. A single tree may house more than 40 different ant species, each of which has a different ecological function and may alter the habitat in distinct and important ways. Ecologists debate about whether systems that have high biodiversity are stable and resilient, like a spider web composed of many strong individual strands, or fragile, like a house of cards. Both metaphors are likely appropriate in some cases. One thing we can be certain of is that it is very difficult in a rainforest system, as in most other ecosystems, to affect just one type of organism. Also, clear cutting one small area may damage hundreds or thousands of established species interactions that reach beyond the cleared area.

Pollination is a challenge for rainforest trees because there are so many different species, unlike forests in the temperate regions that are often dominated by less than a dozen tree species. One solution is for individual trees to grow close together, making pollination simpler, but this can make that species vulnerable to extinction if the one area where it lives is clear cut. Another strategy is to develop a mutualistic relationship with a long-distance pollinator, like a specific bee or hummingbird species. These pollinators develop mental maps of where each tree of a particular species is located and then travel between them on a sort of “trap-line” that allows trees to pollinate each other. One problem is that if a forest is fragmented then these trap-line connections can be disrupted, and so trees can fail to be pollinated and reproduce even if they haven’t been cut.

The quality of rainforest soils is perhaps the most surprising aspect of their ecology. We might expect a lush rainforest to grow from incredibly rich, fertile soils, but actually, the opposite is true. While some rainforest soils that are derived from volcanic ash or from river deposits can be quite fertile, generally rainforest soils are very poor in nutrients and organic matter. Rainforests hold most of their nutrients in their live vegetation, not in the soil. Their soils do not maintain nutrients very well either, which means that existing nutrients quickly “leech” out, being carried away by water as it percolates through the soil. Also, soils in rainforests tend to be acidic, which means that it’s difficult for plants to access even the few existing nutrients. The section on slash and burn agriculture in the previous module describes some of the challenges that farmers face when they attempt to grow crops on tropical rainforest soils, but perhaps the most important lesson is that once a rainforest is cut down and cleared away, very little fertility is left to help a forest regrow.

What is driving deforestation in the Amazon?

Many factors contribute to tropical deforestation, but consider this typical set of circumstances and processes that result in rapid and unsustainable rates of deforestation. This story fits well with the historical experience of Brazil and other countries with territory in the Amazon Basin.

Population growth and poverty encourage poor farmers to clear new areas of rainforest, and their efforts are further exacerbated by government policies that permit landless peasants to establish legal title to land that they have cleared.

At the same time, international lending institutions like the World Bank provide money to the national government for large-scale projects like mining, construction of dams, new roads, and other infrastructure that directly reduces the forest or makes it easier for farmers to access new areas to clear.

The activities most often encouraging new road development are timber harvesting and mining. Loggers cut out the best timber for domestic use or export, and in the process knock over many other less valuable trees. Those trees are eventually cleared and used for wood pulp, or burned, and the area is converted into cattle pastures. After a few years, the vegetation is sufficiently degraded to make it not profitable to raise cattle, and the land is sold to poor farmers seeking out a subsistence living.

Regardless of how poor farmers get their land, they often are only able to gain a few years of decent crop yields before the poor quality of the soil overwhelms their efforts, and then they are forced to move on to another plot of land. Small-scale farmers also hunt for meat in the remaining fragmented forest areas, which reduces the biodiversity in those areas as well.

Another important factor not mentioned in the scenario above is the clearing of rainforest for industrial agriculture plantations of bananas, pineapples, and sugar cane. These crops are primarily grown for export, and so an additional driver to consider is consumer demand for these crops in countries like the United States.

These cycles of land use, which are driven by poverty and population growth as well as government policies, have led to the rapid loss of tropical rainforests. What is lost in many cases is not simply biodiversity, but also valuable renewable resources that could sustain many generations of humans to come. Efforts to protect rainforests and other areas of high biodiversity is the topic of the next section.

Amazon Rainforest Fires

A staggering 26.4 million acres of brazil’s amazon were scorched in 2023, a 35.4% increase from the previous year, deforestation from agriculture and cattle-ranching is a main driver of forest fires in the amazon, expanding and securing land rights of indigenous peoples is one of the best ways to protect the amazon, rainforest foundation us’s response to the amazon fires.

Healthy communities can manage and protect their lands better than anyone. Building on 35 years of steady, dedicated work with Indigenous partners in the Amazon, Rainforest Foundation US provides direct technical support in legal defense, land titling, monitoring, and institutional strengthening, so that Indigenous communities may continue to manage their rainforest territories with the knowledge and care they have sustained for thousands of years.

Throughout the Amazon, we are supporting partners to actively prevent and respond to the threat of fires by:

• Advancing land rights to over 7.9 million acres of Indigenous peoples’ territories in the Amazon regions of Peru, Brazil, and Guyana.
• Expanding Indigenous monitoring programs—some similar to our Rainforest Alert program in Peru—to over 17.5 million acres of tropical forest throughout Central and South America.
• Launching five high-profile advocacy and legal initiatives to improve territorial security for over 34.6 million acres of land and forests.

How do Indigenous Peoples and Land Rights help prevent fires?

Indigenous peoples are the most effective forest stewards . Rainforests held by Indigenous peoples have a lower presence of fire and lower fire temperatures, meaning they’re better able to resist forest loss. Data also shows that rainforests managed by Indigenous peoples contain greater carbon density than state-managed forests  and foster higher levels of biodiversity.

It’s simple: One of the best ways to protect the Amazon from destruction from fire, mining, industrial ranching, and illegal-logging is to secure and expand the land rights of Indigenous peoples living in these territories. Ensuring Indigenous peoples and local communities have rightful governance and control over their territories, as well as access to the necessary technology, training, and resources to manage and protect their territories is crucial to preventing fires and protecting the biodiversity and cultural heritage of the region.

The satellite map below displays real-time fires and Indigenous peoples’ lands. The majority of fires are observed outside Indigenous territories, typically ceasing at their boundaries.,

An area the size of the state of Tennessee burned in the Brazilian Amazon in 2023

While deforestation in the Amazon decreased significantly last year, the forest continued to burn at an alarming rate. For the first time since 2018, the clearance rate was less than 10,000 sq km in the 12 months until 31 July. Still more encouraging, the loss of tree cover in Indigenous territories fell by 73%. Despite these statistics, a staggering 26.4 million acres (10.7 million hectares) of Brazil’s Amazon rainforest burned in 2023—an area comparable in size to the U.S. state of Tennessee—according to MapBiomas Fire Monitor . This represents a 35.4% increase from the previous year.

On average close to 1 million trees are still being chopped down or burned every day in the Amazon. Countless more died because of the drought, and this will worsen the degradation of the forest. Overall, the Amazon was worse off in 2023 than the year prior.

The Impact of Climate Change, El Niño and Unprecedented Drought:

In 2023, researchers’ forecasts came to fruition as the peak of the Amazon fire season aligned with an ongoing El Niño event—a climate phenomenon characterized by the warming of sea surface temperatures in the equatorial Pacific Ocean, which affects rainfall patterns in the Amazon. This perilous combination led to drier conditions, thereby intensifying forest fires.

Indeed, in 2023, the Amazon experienced  the most severe drought in its recorded history , with rivers dropping to record lows, adversely affecting communities and endangering wildlife.

While El Niño significantly contributed to the reduction in rainfall, thereby exacerbating the 2023 drought,  preliminary scientific analyses  have determined that the drought’s extreme severity was mainly due to high temperatures associated with climate change. The probability of such an extreme drought occurring was increased thirtyfold by the climate crisis.

This convergence of climate change, unprecedented temperatures, extreme drought, deforestation, and wildfires underscores the growing concerns for the Amazon’s future.

Amazon fires made global headlines in 2019—four years later were they as bad?

Unfortunately, they were.

In August 2019, massive smoke plumes drifted thousands of miles from the burning Amazon and settled over Sao Paulo, Brazil’s largest city, blocking out the sun.  The world’s attention focused on Jair Bolsonaro’s administration as he opened the Amazon for further exploitation by incentivizing land invasions, mining, ranching and large-scale agriculture, the primary drivers of tropical forest fires.

Despite international pressures, the situation has continued to deteriorate.

Deforestation in the Brazilian Amazon fell by 50% in 2023 compared to the previous year, showing that President Lula da Silva’s efforts to restore environmental protections dismantled by Bolsonaro have achieved some positive results. However, Lula’s administration—weakened in the face of a conservative Congress—has been unable to prevent the passage of legislation that continues to dismantle environmental safeguards and Indigenous peoples’ rights in favor of agribusiness interests. The future of the Amazon hangs in the balance.

Area Burned in Brazil’s Amazon Annually  Since 2019

Why Does the Rainforest Burn?

Tropical forests such as the Amazon are very humid, and under natural conditions they rarely burn—unlike many forests in the western United States where fire is a natural part of the forest’s life cycle.

In the last few decades, two interrelated phenomena have driven Amazon fires: drought, and the expansion of industrial agriculture.

Forests cleared for cattle ranching, agriculture, logging, or illegal mining are cut and then deliberately set on fire once the felled trees are dry enough to burn. Typically, the surrounding forest is wet enough to stop the fire at the edges of new fields and pastures. But prolonged drought in the Amazon basin—linked to climate change and deforestation—means fires are escaping into neighboring intact forests and burning out of control across thousands of acres.

As more forests are cleared, new roads are built, more people move into the area, and new fields are cleared for cattle and crops, creating a vicious cycle that both intensifies the drought and exposes more forests to fire threats.

Scientists warn this cycle is leading the entire Amazon towards a ‘tipping point,’ believed to occur when the combined effects of deforestation and degradation surpass a threshold of 20% to 25% . A new study  warned that the Amazon rainforest could reach this ‘tipping point’ by as soon as 2050. At that point, the world’s largest tropical forest would become so fragmented that it would no longer retain sufficient moisture to sustain itself, leading to catastrophic consequences for the global climate and life on Earth.

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Preserving the Amazon rainforest is of global importance in the fight against climate change, but it is under threat from forest fires, mostly started to clear land for agriculture.

Early numbers from this year's fire season show an increase, leading to concern from scientists.

President Jair Bolsonaro of Brazil recently said that claims the Amazon "is going up in flames" were not true, despite statistics published by his own government showing the spread of fires.

So what does the data show about what's happening this year?

Is the forest in Brazil burning?

Brazil is a huge country with many different environments, including grassland, wetland and rainforest.

Some 60% of the Amazon rainforest is in Brazil, and it plays a vital role in absorbing harmful CO2 that would otherwise escape into the atmosphere. So there's particular concern about the damage that fires might do here.

• Brazil's Amazon sees surge in deforestation
• Amazon under threat: Fires, loggers and now virus

The total number of fires in Brazil's Amazon until July this year is high - but slightly lower than the same period last year.

But there is concern about a surge in blazes last month, earlier than would normally be expected.

"If we consider the average number of fires in July over the period from 2010-2019, then the number of fires in July 2020 represented an increase of 55.6% of the average," says Prof Marcia Castro, a Brazilian scientist based at Harvard University.

"An increase also happened in June (19.6% compared to June last year, and 36.1% compared to the average for the month of June between 2010-19). The peak of the fire season is often seen in August to September.

"So the consistent increase in June and July is worrisome," says Prof Castro.

And alerts so far in August look set to rival the number recorded last year. Fires this year are at the second highest level since 2010.

In the first seven months of 2020, more than 13,000sq km (5,019sq miles) of the Brazilian Amazon was burned, according to analysis of satellite data provided by Dr Michelle Kalamandeen, a tropical ecologist on the Amazon rainforest.

That's more than eight times the size of London.

Dr Kalamandeen says the torched forest often struggles to grow back.

"When a forest is lost, it is gone forever. Recovery may occur but never 100% recovery," she says.

When you look at the spread of the fires in Brazil, during the week of 11 August, there were noticeable clusters of fires in the Amazon, with Para, Mato Grosso, Amazonia and Rondonia states reporting a high number of alerts.

In areas around Novo Progresso in Para state, farmers reportedly held a "day of fire" last year and satellites have picked up more than 1,300 fire alerts in the past month, according to official statistics.

To the north-east, the large municipality of Altamira has recorded the most fires in Brazil's Amazon region during this period.

What could make it worse this year?

Brazilian climate scientist Carlos Nobre says there are two main issues contributing to forest fires this year.

The first is that this year's dry season is much drier than usual.

"The waters of the tropical north Atlantic are warmer this year and when that happens, we have less rainfall over the southern Amazon," says Professor Nobre.

The second is that there is a lot of felled forest left over from last year's logging - this is chopped wood that can fuel fires.

A lot of it didn't get burned as there was a military campaign to stop illegal activity in the forest

This year, the army has been conducting an operation to stop deforestation since June, and in July, President Bolsonaro imposed a four-month ban on forest fires.

Vice-President Hamilton Mourao recently launched a campaign against the fires, including an app for the public to report them.

"We will be out in the field in August to try to stop these fires becoming worse than last year," he told the BBC.

Activists and government critics remain sceptical, says Camilla Costa, a BBC World Service journalist.

According to the Brazilian defence ministry, 28,100 cubic metres of illegal wood has been confiscated with fines totalling 407.2 million Brazilian reais ($72.6m; £55m).

However, fires have continued in the region and critics complain about a lack of sufficient enforcement.

Is the forest on fire in other countries?

The number of forest fires in the Amazon regions of Colombia, Peru and Venezuela is up on this time last year.

For Amazonian countries, mining and agriculture is driving deforestation and as a result forest fires, according to Dr Kalamandeen.

In Venezuela, an increase in mining for gold is likely to be behind the increase, as since 2016 President Nicolas Maduro has opened up the sector to try and stem the country's economic collapse.

In Colombia, following the government's rapprochement with rebel group Farc in the past few years, areas have been opened up for farming, causing an increase in blazes, says Dr Kalamandeen.

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Amazon Fire Monitoring and Analysis Based on Multi-source Remote Sensing Data

J Q Yao 1,2 , H R Zhai 1 , X M Tang 1,2 , X M Gao 1 and X D Yang 1,3

Published under licence by IOP Publishing Ltd IOP Conference Series: Earth and Environmental Science , Volume 474 , 3. Geological Resources Exploration and Development Citation J Q Yao et al 2020 IOP Conf. Ser.: Earth Environ. Sci. 474 042025 DOI 10.1088/1755-1315/474/4/042025

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1 Land Satellite Remote Sensing Application Center, Ministry of Natural Resources of P.R. China, Beijing, 100048, China

2 College of Geomtics, Shandong University of Science and Technology, Qingdao 266590, China

3 School of Geomatics, Liaoning Technical University, Fuxin 123000, China

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In August 2019, a large-scale fire broke out in the Amazon rainforest, bringing serious harm to the ecosystem and human beings. In order to accurately monitor the dynamic change of forest fire in Amazon rainforest and analyse the impact of fire spreading and extinction on the environment, firstly, based on NPP VIIRS data covering the Amazon fire area, the sliding window threshold method is adopted to extract the fire point, and the cause of fire change is monitored and analysed according to the time series. Secondly, based on the time series of CALIPSO data, the vertical distribution changes of atmospheric pollutants in the amazon fire area are analysed, and the comprehensive analysis is carried out by combining NPP VIIRS data. The experimental results show that only NPP VIIRS data is used to predict the fire, and the combination of CALIPSO data can better monitor the forest fire and predict the fire development trend. The combination of optical image and laser radar has greater advantages in dynamic fire monitoring and fire impact analysis. The method described in this paper can provide basic data reference for real-time and accurate prediction of forest fires and provide new ideas for dynamic fire monitoring.

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Case Study: Fires Around the World

Banking on climate chaos 2021.

This blog was originally published as a case study in “Banking on Climate Chaos: Fossil Fuel Finance Report 2021” — a report by Rainforest Action Network, BankTrack, Indigenous Environmental Network, Oil Change International, Reclaim Finance, and Sierra Club. You can see the full report here . Photo credit: Paul Hilton

Although 2020 will always be remembered as the year in which the COVID-19 pandemic took hold, the coronavirus was not the year’s only thematic disaster: 2020 was also a year of massive forest fires, reminding the world that climate chaos is here and now. 

One of the most tangible consequences of climate change is the increase in the frequency and intensity of these fires. While some fires are more directly attributable to land clearing and bad forest management , climate change is certainly worsening the problem . The climate crisis exacerbates forest fires in several ways : warmer conditions mean a longer fire season, climate change leads to more extreme weather events and therefore also more extreme droughts , and a warmer atmosphere leads to higher evaporation rates, which dries out the soils and also increases lightning . It is therefore no surprise that 2020 featured an increase in forest fires in many parts of the world including the Arctic , Australia , the U.S. West Coast , and the Amazon . Though the devastating, headline-grabbing fires in the Amazon have been intentionally set to clear land for agribusiness , climate chaos is making the arson more destructive.

Forest fires most heavily affect local communities, who often see their homes, sources of income, and food security go up in flames. Downwind, the air quality can deteriorate to such an extent that whole cities are shrouded in smoke . Forest fire smoke is extremely harmful to the lungs, especially for children and adults with asthma, COPD, bronchitis, or chronic heart disease. Last but not least, forest fires release enormous amounts of greenhouse gases into the atmosphere, further worsening the climate crisis.

In the meantime, the fossil fuel industry continues to expand fossil fuel production, thereby exacerbating climate change and worsening the frequency and magnitude of future forest fires. And the banks that finance this industry with little restraint — like the top bankers of fossil fuels JPMorgan Chase , Citi , and Wells Fargo — share in the responsibility for these impacts.  The public is increasingly starting to recognize the companies responsible for these so-called natural disasters. Last year, an Australian bushfire victim filed a complaint with the Organisation for Economic Co-operation and Development (OECD) against ANZ for its role in worsening the massive forest fires in Australia by continuing to finance fossil fuels.

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New study on Amazonia's fire crises urges action ahead of the next burning season

In response to the escalating fire crises in the Amazon, a timely study has revealed alarming shortcomings in the emergency fire bans implemented by the Brazilian Government. Initially seen as a promising solution in 2019, these bans have consistently fallen short in subsequent years, revealing a pressing need for strategies that address the underlying causes of each type of fire.

Dr Manoela Machado , a Postdoctoral Researcher at the Environmental Change Institute at the University of Oxford and also at the Woodwell Climate Research Center, and the lead author of the study, said: 'Emergency fire bans are not a standalone solution for the fire crises; they can be effective when strategically implemented and rigorously enforced during critical periods to prevent ignitions, but to solve the crises, we need measures that address the motivations behind different types of fires and, most crucially, focus on stopping deforestation.'

The Amazon plays an essential role in regulating global climate patterns, supporting biodiversity, and sustaining local and Indigenous communities. The persistent inability to effectively manage these fires not only jeopardises the ecological integrity of the Amazon but also intensifies global climate change and negatively impacts human health and well-being. Dr Erika Berenguer , a co-author of the study, said: 'When deforestation or pasture fires escape into surrounding forests, they can kill up to 50% of the trees, considerably contributing to both the climate and the biodiversity crises. It is imperative to halt these other fire types in order to avoid burning Amazonian forests.'

This study underscores the urgent need for strong political commitment ahead of the next burning season, anticipated to peak in July and August and likely worsened by recent El Niño conditions. Dr Machado said: 'A drier and hotter climate favours the spread of fires, so it’s crucial to prevent ignitions when the environment is most fire-prone.'

The study highlights the inadequacy of reactive measures and the critical need for a shift toward proactive, comprehensive strategies, which include targeted interventions, effective landscape management, engaged community involvement, robust public awareness campaigns, and crucially, stopping deforestation. Co-author Dr Imma Oliveras Menor added: 'Future directions should take into account the important role of social actors such as Indigenous and local communities, and establish effective multi stakeholder communication and interoperability.'

Link to the research paper in Communications Earth & Environment Journal - Emergency policies are not enough to resolve Amazonia’s fire crises

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Amazon Rainforest fire: Cause, impact, everything you need to know

Amazon rainforest fire: bolivia has ordered the world's largest air tanker, boeing 747 ‘supertanker’ , to put out the blazing amazon rainforest fire..

Amazon Rainforest fire: Amazon rainforest, the world's largest  rain forest is at the risk of getting burned out completely. The rainforest, which contributes almost 20 percent of the earth’s oxygen, has been burning for over 16 days resulting in a major loss of trees and biodiversity.  It will get completely burned out if it is not put out soon. 

Amazon rainforest fire impact can already be seen in different regions in South America including the Atlantic coast and Sao Paulo, Brazil’s largest city. Sao Paulo plunged into sudden darkness around 3 pm on Monday. A dark, smoky cover seemed to envelop the city and the rain that poured down smelled like smoke. Sao Paulo is located about thousands of kilometers away from the burning fire.

Amazon rainforest fire from space

Amazon Rainforest Fire Cause

Though forest fires are common in the Amazon during this period, as it is a dry season in the southern Amazon, the year 2019 has seen an unprecedented rise in the number of the fires and their intensity. The worrisome fact is that the burning has increased at a time when there is a huge decrease in the rates of deforestation in Brazilian Amazon.

According to environmentalists, 99 percent of the forest fires are a result of human actions, either on purpose or by accident. Farmers and ranchers use fire generally to clear the land for further utilisation. This year's fires also fit perfectly into the established seasonal agricultural pattern. This time is the most suitable to burn because the vegetation is dry. Farmers generally wait for the dry season to start burning and clearing areas so that their cattle can graze, However, peak of the dry season is yet to come in September.

Environmentalists blame Brazilian President Jair Bolsonaro

The environmentalists are blaming Brazilian President Jair Bolsonaro for the forest fires.  When Bolsonaro was running for president, he had promised to restore Brazil's economy by exploring the economic potential of the Amazon rainforest. As per environmentalists, Bolsonaro has encouraged the farmers and ranchers to exploit and burn the rainforest like never before.

The UN Secretary General Antonio Guterres also expressed deep concern over the blazing fire in the Amazon rainforest.

Amazon Rainforest Fire: Impact

The fire in Brazil’s Amazon rainforest has been burning at the highest rate. There have been around 72,843 fires in Brazil in 2019 itself, with more than half in the Amazon rainforest. This shows an 80 percent increase in fires during the same period in 2018.

According to scientists, the Amazon rainforest fire could deliver a huge blow to the global fight against climate change. The fire will not only result in a major loss of trees and biodiversity but also release excess CO2 into the atmosphere.  The forest fires also release pollutants including particulate matter and toxic gases such as carbon monoxide, nitrogen oxides and non-methane organic compounds into the atmosphere

Amazon rainforest, considered to be as the planet’s lungs as it contributes about 20 percent of the earth’s oxygen, is vital to slow down global warming. The rainforest is currently home to uncountable species of fauna and flora. While the immediate impact of the fire would be changes in the heating of the regional atmosphere, in the long term it is expected to lead to a potential decline in natural carbon.

Bolivia orders world's largest air tanker to put out the Amazon rainforest fire

The Amazon rainforest is the largest rainforest on Earth. The rainforest creates 20 percent of the oxygen in Earth’s atmosphere.

The rainforest is home to 40 percent of the worlds tropical forest and holds 20 percent of the worlds freshwater supply. It is also home to 10 percent of the world’s species and 40,000 plant species and around 3000 varieties of edible fruits.

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Climate Forward

‘narco-deforestation’ and the future of the amazon.

The fate of Colombia’s rainforest may lay in the hands of a rebel group linked to drugs and illegal mining.

By Manuela Andreoni

There’s a struggle for law and order in many of the world’s tropical forests, and nature is losing.

Last week, I wrote about the major progress Colombia made in 2023, slashing deforestation rates by 49 percent in a single year. But this week, we learned the trend reversed significantly in the first quarter of this year. Preliminary figures show tree loss was up 40 percent since the start of the year, Colombia’s Minister of Environment, Susana Muhamad, told reporters on Monday .

Why have things changed so quickly? Mostly because a single armed group controls much of Colombia’s rainforests.

Muhamad explained that conflicts with Estado Mayor Central, a group that is thought to run a sprawling cocaine operation among other illegal activities, were partly behind the striking numbers. “In this case, nature is being placed in the middle of the conflict,” she said. According to experts, E.M.C. had largely banned deforestation and in recent months it seems to have allowed it again.

A 2023 United Nations report referred to this entanglement between drug trafficking and environmental crime as “ narco-deforestation .” Perhaps nowhere is that phenomenon more clear than in Colombia, a country that’s both a stage for the decades-old global war on drugs and one of the most biodiverse corners of the planet, where the Andes Mountains meet the vast Amazon rainforest.

But what’s happening in Colombia underscores a growing challenge for many developing countries. Vast pristine forests are both essential to curb climate change and biodiversity loss, and they’re also prized by groups who want to hide illegal activities beneath thick tree canopies.

Today I want to explain why experts on the ground say that there’s no way to protect crucial forests like the Amazon without dealing with the growing power of armed groups.

The Colombian case

Armed groups in Colombia have long prohibited logging in the forest. The main reason, experts say, was to protect the illegal drug operations that the Revolutionary Armed Forces of Colombia, or FARC, ran in the forest.

FARC’s role protecting the forest became clear after 2016, when it signed a peace deal with the Colombian government, which disarmed the group and turned it into a political party called Comunes . When FARC disbanded, a local power vacuum caused deforestation rates to skyrocket as cattle ranchers, illegal miners and dissident groups cut down forests.

But as the dust settled, the Estado Mayor Central, a dissident group controlled by Ivan Mordisco, a former FARC commander , consolidated power in much of the Colombian rainforest. The old FARC tactics of restricting logging seemed to return and deforestation rates started to fall again. Until recently.

Muhamad noted that El Niño may have also made the Amazon more vulnerable to forest fires this year. I called Rodrigo Botero, the director of an environmental nonprofit in Colombia called the Foundation for Conservation and Sustainable Development, to understand what else changed. He told me they can see new roads being opened and ranches expanding in the region. Government agents can’t stop it because the group, which is estimated to have over 3,000 troops , controls access to much of the forest.

It’s not totally clear why the E.M.C. seems to have begun allowing logging again. Botero said he feared the E.M.C. could be trying to use deforestation rates as leverage to get more favorable treatment from the government.

First, they showed the government the benefits they could deliver by forbidding deforestation, he explained. And then, Botero added, it was like they told the government, “if you can’t count on us, look at what we can do.”

It’s a global problem, too

There is no evidence that the E.M.C. were successful in what seems to be an attempt to use the Amazon as a political tool. The government says it’s actively trying to arrest Mordisco .

Politics aside, what the Colombian case made clear to me is that controlling armed groups is now a fundamental part of conservation policy.

Bram Ebus, a consultant at the International Crisis Group and an investigative reporter, has spent years documenting how both drug traffickers and rebel groups like the E.M.C. are expanding their reach in the rainforests of South America in a project called Amazon Underworld .

He told me the illegal trade managed by these powerful criminal groups is no longer restricted to drugs or minerals, though they are still major sources of income. There is growing concern that criminal networks are also tapping into a vast menu of businesses to launder their illegal gains, such as illegal logging, wildlife trafficking, ranching and land grabbing.

Researchers, journalists and government officials have long documented how mining funded conflict in Africa, Asia and Latin Americ a. Nature was collateral damage. Illegal mining operations connected to conflict have been very harmful to biodiversity in the Congo River Basin’s rainforest , for example.

Colombia continues to negotiate for peace, and its Ministry of Environment and Sustainable Development didn’t comment on whether the Amazon was being used as a political tool, but added that violations will be investigated and that it will continue working to curb deforestation. (The E.M.C. could not be reached for comment.) But, in many cases, it’s becoming hard to tell politically motived groups from purely criminal gangs. That’s bad news for nature and whoever dares defend it .

Many countries simply don’t have the resources to protect forests, let alone take on armed groups. Right now, one of the developing countries with the biggest budget for forest protection, Brazil, has so few officers that each worker patrols on average an area the size of Denmark, according to an association of environmental protection officers. They are now striking to protest poor working conditions .

Meanwhile, criminal and rebel groups have continued to expand their reach.

“You see that all these groups who are participating in the conflict have one key objective, which is to expand, to get more troops, to get more money, to get more territorial control,” Ebus told me. “The environment right now is a hostage of war.”

Getting rid of ‘forever chemicals’

What happened : For the first time, the federal government is requiring municipal water systems to remove six synthetic chemicals linked to cancer and other health problems that are present in the tap water of hundreds of millions of Americans, my colleague Lisa Friedman reported.

The Environmental Protection Agency will start requiring that water providers reduce perfluoroalkyl and polyfluoroalkyl substances, known collectively as PFAS, to near-zero levels. The compounds, found in everything from dental floss to firefighting foams to children’s toys, are called “forever chemicals” because they never fully degrade and can accumulate in the body and the environment. The new effort will cost at least $1.5 billion per year.

Where PFAS are found: The chemicals are so ubiquitous that they can be found in the blood of almost every person in the United States. A recent study that tested 45,000 water samples around the world found that about 31 percent of samples that weren’t near any obvious source of contamination had PFAS levels considered harmful to human health, as my colleague Delger Erdenesanaa wrote this week .

Exposure to PFAS has been associated with metabolic disorders, decreased fertility in women, developmental delays in children and increased risk of some prostate, kidney and testicular cancers, according to the E.P.A. (Lisa wrote a helpful explainer on what else we need to know about PFAS .)

The new regulation is “life changing,” Michael S. Regan, the E.P.A. administrator, told Lisa. “We are one huge step closer to finally shutting off the tap on forever chemicals once and for all.”

So what can you do to avoid PFAS? The E.P.A. maintains a list of cleaning products that are safe from these chemicals . And the Environmental Working Group, a nonprofit, has been tracking companies that say they are stripping them from their products. — Manuela Andreoni

More climate news

H&M and Zara are buying cotton linked to environmental destruction and land grabbing in Brazil’s grasslands, according to an investigative report reviewed by Context .

Solar power plants produced more energy in Texas than coal for the first time in March, Canary Media reports .

The Washington Post maps access to nature in neighborhoods across the United States .

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If you’re enjoying what you’re reading, please consider recommending it to others. They can sign up here . Browse all of our subscriber-only newsletters here . And follow The New York Times on Instagram , Threads , Facebook and TikTok at @nytimes.

Reach us at [email protected] . We read every message, and reply to many!

Manuela Andreoni is a Times climate and environmental reporter and a writer for the Climate Forward newsletter. More about Manuela Andreoni

Learn More About Climate Change

Have questions about climate change? Our F.A.Q. will tackle your climate questions, big and small .

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• Published: 13 July 2022

The 2019–2020 Australian forest fires are a harbinger of decreased prescribed burning effectiveness under rising extreme conditions

• Hamish Clarke 1 , 2 , 3 , 4 ,
• Brett Cirulis 4 ,
• Trent Penman 4 ,
• Owen Price 1 , 2 ,
• Matthias M. Boer 2 , 3 &
• Ross Bradstock 1 , 2 , 3 , 5  

Scientific Reports volume  12 , Article number:  11871 ( 2022 ) Cite this article

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• Natural hazards

There is an imperative for fire agencies to quantify the potential for prescribed burning to mitigate risk to life, property and environmental values while facing changing climates. The 2019–2020 Black Summer fires in eastern Australia raised questions about the effectiveness of prescribed burning in mitigating risk under unprecedented fire conditions. We performed a simulation experiment to test the effects of different rates of prescribed burning treatment on risks posed by wildfire to life, property and infrastructure. In four forested case study landscapes, we found that the risks posed by wildfire were substantially higher under the fire weather conditions of the 2019–2020 season, compared to the full range of long-term historic weather conditions. For area burnt and house loss, the 2019–2020 conditions resulted in more than a doubling of residual risk across the four landscapes, regardless of treatment rate (mean increase of 230%, range 164–360%). Fire managers must prepare for a higher level of residual risk as climate change increases the likelihood of similar or even more dangerous fire seasons.

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Introduction

Intrinsic to the earth system for hundreds of millions of years, wildfires are increasingly interacting with humans and the things we value 1 , 2 , 3 . Mega-fires in recent years have caused loss of life and property and widespread environmental and economic impacts in many countries, challenging society’s ability to respond effectively 4 , 5 , 6 . Climate change has already caused changes in some fire regimes, with greater changes projected throughout this century 7 , 8 , 9 . There is a broad network of anthropogenic influences on fire likelihood, exposure and vulnerability including land-use planning, building construction and design, insurance, household and community actions, Indigenous cultural land management, ecosystem management, and research and development. Within this network, fire management agencies play a critical role in wildfire risk mitigation, although our understanding of the interactions between, and relative contributions of, these varied factors towards risk mitigation remains limited. Addressing these gaps is required to support the development and implementation of cost-effective risk management strategies 10 .

Prescribed burning is commonly used in contemporary fire management to alter fuels, with the intention of mitigating risks posed by wildfires to assets. This involves the controlled application of fire in order to modify fuel properties and increase the likelihood of suppressing any wildfires that subsequently occur in the area of the burn 11 , 12 , 13 . Although the effects and effectiveness of prescribed burning have come under intense scientific scrutiny 14 , major knowledge gaps remain in the design of locally tailored, cost-effective treatment strategies that aim to optimise risk mitigation across a range of management values 15 . Crucially, these values may sometimes be in conflict e.g. smoke health impacts from prescribed fire and wildfire 16 or biodiversity conservation and asset protection 17 , necessitating methods for making trade-offs explicit 18 .

The 2019–2020 fires in south-eastern Australia resulted in 33 direct deaths, over 400 smoke-related premature deaths, the loss of over 3000 houses and new records for high severity fire extent and the proportion of area burnt for any forest biome globally 4 , 19 , 20 , 21 . These fires were an important opportunity to test the risk mitigation effects of prescribed burning. One empirical study found that about half the prescribed fires examined resulted in a significant decrease in fire severity, with effects greater for more recent burns and weaker for older burns 22 . Two other empirical studies 6 , 23 found decreases in the probability of high severity fire and house loss after past fire (either prescribed fire or wildfire), but also that this effect was significantly weakened under extreme fire weather conditions, consistent with prior research 24 , 25 . Large ensemble fire behaviour modelling can complement these empirical studies by exploring far more variation in weather conditions, treatment strategies and ignition location than would be possible from the historical record 26 , 27 , 28 . Simulation modelling facilitates estimates of residual risk: the percentage of maximum bushfire risk remaining, in a given area, following a particular fire management scenario, with maximum typically based on a control scenario with no prescribed burning treatment 29 . Simulation modelling also enables tracking of the trajectory of risk in the aftermath of seasons such as the 2019–2020 one, where very large burned areas might be expected to have reduced landscape fuel loads and hence residual risk.

Here we perform a simulation experiment on the effects of different rates of prescribed burning treatment on area burnt and the risks posed by wildfire to multiple values. We consider life, property and infrastructure across four case study landscapes (Fig. 1 ). In particular, we asked:

How much risk mitigation does prescribed burning provide in the weather conditions of 2019-20 compared to average fire season weather distributions, based on long-term records?

How much subsequent risk reduction did the Black Summer fires provide?

Over what time period will risk reduction be measurable?

Fire behaviour simulations were carried out for four case study landscapes in south-eastern Australia: Casino, Gloucester, Blue Mountains and Jervis Bay. See Table 1 and Study Area in the Methods section for more information. This figure was generated using ArcGIS version 10.8 ( https://www.esri.com/en-us/home ).

The effect of 2019-20 fire weather conditions on risk mitigation from prescribed burning

Fire weather conditions during the 2019–2020 season were markedly different to preceding years (Fig. 2 ). In all four case study landscapes there were fewer Low-Moderate days (Forest Fire Danger Index (FFDI): 0–12) and often considerably more High, Very High and Severe days (FFDI: 12–74). Only in the Jervis Bay landscape were there substantially more Extreme days (FFDI: 75–99) during the 2019–2020 season, while there were no Catastrophic days (FFDI ≥ 100) in any of the landscapes during 2019–2020.

Relative frequency of FFDI categories from half-hourly weather station data during the long-term record (1995–2014 for Casino, 1991–2014 for Gloucester and Blue Mountains, 2000–2014 for Jervis Bay) and during the 2019–2020 season.

The 2019–2020 weather conditions strongly increased the residual risk of area burnt by wildfire and house loss due to wildfire (Figs. 3 , 4 ). For any given treatment rate, the residual risk under 2019–2020 weather conditions far exceeded control conditions (i.e. conditions based on long-term historic weather). For area burnt there was a mean 220% increase in residual risk (range 170–351%), while for house loss the mean increase in residual risk was 244% (range 164–360%). Only under very high rates of treatment was prescribed burning under 2019–2020 conditions able to achieve a residual risk below that of zero treatment in the control scenario, and only for house loss in the Blue Mountains (Fig. 4 ). Elsewhere even the highest rates of treatment (well above rates achieved historically) resulted in a residual risk above that of zero treatment in the control scenario.

Residual risk trajectory of area burnt by wildfire in Casino, Gloucester, Blue Mountains and Jervis Bay. Risk is relative to a scenario with no prescribed burning and long-term weather (the 100% level on the y-axis). Markers represent different annual rates of treatment, colours represent different weather conditions (blue = control i.e. long-term, orange = 2019–2020 fire season).

Residual risk trajectory of houses lost due to wildfire in Casino, Gloucester, Blue Mountains and Jervis Bay. Risk is relative to a scenario with no prescribed burning and long-term weather (the 100% level on the y-axis). Markers represent different annual rates of treatment, colours represent different weather conditions (blue = control i.e. long-term, orange = 2019–2020 fire season).

Prescribed burning resulted in a reduction in residual risk in all landscapes regardless of weather conditions, even though in almost all cases the risk remained higher than for zero treatment in the control scenario (see gradient of markers in Figs. 3 , 4 ). The effect of increasing treatment was much stronger in the Blue Mountains, with a minimum residual risk of area burnt by wildfire under long-term weather conditions of 35%, and a minimum residual risk of house loss of 22%. In the other three landscapes the minimum residual risk was 89% for area burnt and 77% for house loss. The marginal effect of prescribed burning (i.e. the rate of change in risk mitigation with incremental changes in treatment rate) was greater under the extreme 2019–2020 weather conditions, even though the residual risk was much higher as described above. Results for life loss and infrastructure damage were similar (Supplementary Figures 1 –3).

Risk in the aftermath of 2019–2020 fire season

The estimated fuel load reductions due to the 2019–2020 fire season were predicted to cause widespread short-term reductions in residual risk to area burnt by wildfire and house loss, regardless of treatment level (Figs. 5 , 6 ). The potential area burnt by wildfire in 2021 was predicted to be at 30–80% of control (i.e. pre-2019–2020 levels) depending on landscape (Fig. 5 , circles). The predicted reduction in area burnt was greatest in Jervis Bay and Gloucester, which experienced the greatest and second greatest proportion burnt during the 2019–2020 season respectively (Table 1 ). By 2025, the residual risk of area burnt by wildfire climbed to 50–90% of control levels across the four study areas (Fig. 6 ). Results are similar for house loss (Fig. 6 ) i.e. the reductions in future wildfire risk due to the 2019–2020 season are partial and temporary, with residual risk actually exceeding control levels in the Blue Mountains by 2025. The re-accumulation of fuel over time is predicted to lead to greater risk mitigation from prescribed burning by 2025 than by 2021 (compare the gradients of the crosses and the circles in Figs. 5 , 6 ). As with the previous analysis, results for life loss and infrastructure damage were similar (Supplementary Figures 4 -6).

Future residual risk trajectory of area burnt by wildfire in the Casino, Gloucester, Blue Mountains and Jervis Bay case study areas. Risk is relative to a control scenario with pre-2019–2020 fuel load and no prescribed burning (the 100% level on the y-axis, indicated by line). Markers represent different annual treatment rates, colour indicates time period (blue = 2021 i.e. two years after 2019–2020 fire season, orange = 2025 i.e. six years after 2019–2020 fire season). In Jervis Bay the markers for 2, 3 and 5% p.a. treatment reflect edge treatment rates, with landscape treatment capped at 1% p.a. due to the very large area burnt during the 2019–2020 season (81% of the study area).

Future residual risk trajectory of houses lost due to wildfire in the Casino, Gloucester, Blue Mountains and Jervis Bay case study areas. Risk is relative to a control scenario with pre-2019–2020 fuel load and no prescribed burning (the 100% level on the y-axis, indicated by line). Markers represent different annual treatment rates, colour indicates time period (blue = 2021 i.e. two years after 2019–2020 fire season, orange = 2025 i.e. six years after 2019–2020 fire season). In Jervis Bay the markers for 2, 3 and 5% p.a. treatment reflect edge treatment rates, with landscape treatment capped at 1% p.a. due to the very large area burnt during the 2019–2020 season (81% of the study area).

Weather conditions during the 2019–2020 Australian fire season were a substantial risk multiplier compared to long-term weather conditions. The relative risks due to wildfire, quantified in terms of area burnt or house loss, doubled in three of four forested landscapes and more than tripled in the other. While prescribed burning partially mitigated these risks, the effect size was typically dwarfed by the effect of extreme weather conditions. In most cases zero treatment under long-term historic weather conditions yielded a lower residual risk than even the highest prescribed burning rates when combined with the 2019–2020 fire weather conditions. We also found that wildfire risk was likely to be reduced in the aftermath of the 2019–2020 fires, based on the implied fuel reduction associated with the unprecedented area burnt during the 2019–2020 season. However, the residual risk was still substantial in some areas and was predicted to rise steadily in the coming years, regardless of prescribed burning treatment rates.

Prescribed burning can mitigate a range of risks posed by wildfire, however residual risk can be substantial and is likely to increase strongly during severe fire weather conditions 6 , 24 . We found that the risk mitigation available from prescribed burning varies considerably depending on where it is carried out and which management values are being targeted, consistent with previous modelling studies that suggest there is no ‘one size fits all’ solution to prescribed burning treatment 15 , 16 . Of the factors influencing regional variation in prescribed burning effectiveness, the configuration of assets and the type, amount and condition of native vegetation are likely to be important. The Blue Mountains landscape, where area burnt by wildfire responded most strongly to treatment, has a relatively high proportion of native vegetation compared to the other landscapes, particularly Casino and Gloucester which are mostly cleared. The Blue Mountains also has an unusual combination of a high population concentrated in a linear strip of settlements surrounded by forest, which may contribute to greater returns on treatment (Fig. 1 ). Future research could systematically investigate the relationship between risk mitigation and properties of key variables such as asset distribution, vegetation and burn blocks for an expanded selection of landscapes. Although residual risk was greatly reduced in some areas after the 2019–2020 fire season, it remained substantial in other areas and was generally predicted to rise rapidly with fuel re-accumulation over the following five years. More work is needed to understand potential feedbacks between increasing fire activity, fuel accumulation and subsequent fire activity 8 .

Our conclusions are dependent on a number of assumptions associated with our fire behaviour simulation approach, including the foundational premise that fire spread is a function of fire weather, fuel load and factors such as topography. Fire behaviour simulators built on these assumptions have known biases and perform better when these are addressed, although their tendency to underestimate extreme fire behaviour suggests our results may be conservative 30 , 31 , 32 . The approach also assumes that both wildfires and prescribed burns consume equivalent quantities of fuel and that this fuel starts to re-accumulate after fire as a negative exponential function of time since fire, eventually stabilising at an equilibrium amount. In fact fuel consumption rates vary considerably within a given fire but also between wildfires and prescribed fires, which consume less fuel 33 , 34 . This also points towards our results being conservative due to potentially overestimating the mitigation effect of prescribed burning. Furthermore the accumulation of fuel post fire depends on the vegetation type, soil and climate 35 . Our experiments on the trajectory of risk after the 2019–2020 fire season may be limited by the relatively short amount of time allowed to elapse, which may be insufficient for prescribed burning treatment effects to become apparent. More broadly, our study design involves repeated instances of a single wildfire and thus does not capture the fire regime i.e. the effects of multiple fires in space and time, nor does it factor in future changes in climate, fuel or fuel moisture 36 . We did not model suppression, which is a complex function of fuel type, fuel load, fire behaviour, weather, topography and fire management decision making 37 . Suppression can reduce a range of risks although it is less effective under extreme weather conditions 38 , 39 , 40 .

Fire-prone landscapes around the world have experienced increasingly severe fire weather conditions 20 , 41 . The extreme conditions of the 2019–2020 fire season are projected to occur more frequently in the 21st century 42 . Our results suggest that climate change could seriously undermine the role played by prescribed burning in wildfire risk mitigation, as found in previous studies 43 , 44 . Using landscape simulation modelling in the Blue Mountains and the Woronora Plateau (about 100 km north of our Jervis Bay landscape), Bradstock et al. 43 found that the rate of prescribed burning treatment would need to quintuple or more by 2050 to counteract the effects of climate change on risk mitigation in terms of measures such as area burned and intensity of unplanned fire. Our study assumes that similar or greater treatment rates will be possible in future, which may not be the case depending on the prevalence of suitable prescribed burning weather conditions 45 , 46 . These findings demonstrate that there can be no wildfire risk mitigation without effective climate change mitigation 47 . Our research reinforces the need for comprehensive, transparent and objective evaluation of the effectiveness of existing attempts to mitigate wildfire risk across a range of management objectives, with future work potentially targeting additional management values such as smoke production and associated health impacts, agriculture and tourism impacts, and more nuanced measures of environmental impact. Such an evaluation could inform the trial and implementation of a range of locally tailored risk mitigation measures that address the full complexity of fire across preparation, response and recovery phases, such as prescribed burning, mechanical fuel reduction, anthropogenic ignition management, suppression, planning, construction and community engagement.

We selected four case study landscapes that were extensively impacted during the 2019–2020 fire season: Casino (69,362 ha burnt), Gloucester (132, 281 ha), Blue Mountains (119,626 ha) and Jervis Bay (137,049 ha) (Fig. 1 ; Table 1 ). All landscapes are forested, have considerable Wildland Urban Interface (WUI), and have a history of both wildfire and prescribed fire. Case study landscapes were approximately 200,000 ha (Table 1 ), intended to align with the upper limit of the size distribution of wildfires in local ecosystems (During the 2019–2020 fire season the Gospers Mountain fire, the result of mergers between several large fires in the Blue Mountains World Heritage Area and neighbouring areas, had a final burned area of over 500,000 ha).

The dominant land cover in the Casino landscape is cleared or modified vegetation (58%). The main native vegetation is dry sclerophyll forest with a shrub/grass understorey (17% of the study area) followed by wet sclerophyll forest with a grassy understorey (9%). The Casino area has a population of about 12,000, mostly concentrated in the town of Casino with a small number dispersed on semi-rural properties. Cleared or modified vegetation is also the dominant land cover in the Gloucester landscape (60%). The main native vegetation is wet sclerophyll forest with a grassy understorey (23% of the study area) followed by wet sclerophyll forest with a shrubby understorey (8%). The population is about 30,000, most of which live in the town of Taree on the eastern edge of the landscape with the remainder in smaller towns and semi-rural properties. The main native vegetation in the Blue Mountains landscape is dry sclerophyll forest with a shrubby understorey (63% of the study area) followed by dry sclerophyll forest with a shrub/grass understorey (9%). About 11% of the landscape is cleared or modified vegetation. Around 100,000 people live within the area, mainly living in a string of suburbs along a highway which bisects the region. The main native vegetation in the Jervis Bay landscape is dry sclerophyll forest with a shrubby understorey (40% of the study area) followed by wet sclerophyll forest with a grassy understorey (17%). Around 14% of the landscape is cleared or modified vegetation. About 50,000 people live within the area, mostly in the township of Nowra in the northeast with most of the remainder in coastal suburbs in the southeast.

All four landscapes are examples of the temperature eucalypt forest fire regime niche, characterised by high-productivity, with infrequent low-intensity litter fires in spring and medium-intensity shrub fires in spring and summer 48 . Fire intensity typically ranges from 1000 to 5000 kW m −1 , although extreme weather conditions may support crown fires where fire intensity can reach 10,000–50,000 kW m −1 . Fire interval is around 5–20 years, although can be as long as 20–100 years 48 . Contemporary prescribed burning rates average 2.5% p.a. in the Blue Mountains landscape and range from 0.4 to 0.6% p.a.in the Casino, Gloucester and Jervis Bay landscapes.

Phoenix fire simulator

Fires were simulated using PHOENIX RapidFire v4.0.0.7 49 , which is commonly applied in operations across south-eastern Australian states, including NSW 17 . Fire growth and rate of spread are calculated from Huygens’ propagation principle of fire edge 50 , a modified McArthur Mk5 forest fire behaviour model 51 , 52 and a generalisation of the CSIRO southern grassland fire spread model 53 . A 30-m resolution digital elevation model was included to allow PHOENIX to incorporate topographic effects on fire behaviour. Vegetation mapping and fuel accumulation models for major vegetation types of the case study landscapes were supplied by the NSW Rural Fire Service. Simulations were run at 180m grid resolution and model output included flame length, ember density, convection and intensity.

Scenario parameterisation

PHOENIX estimates fuel loads using separate fuel accumulation curves for combined surface and/near-surface, elevated and bark fuels 54 . These curves are based on a negative exponential growth function and varied among vegetation types 55 . The treatable portion of each case study landscape was defined as all fuels except crop, farm and urban landcover, and comprised 38% of the Casino landscape, 52% of the Gloucester landscape, 70% of the Blue Mountains landscape and 83% of the Jervis Bay landscape. Treatable fuels were separated into two types of management-sized ‘burn blocks’. Edge blocks were adjacent to property and settlements, while landscape blocks were more remote and larger. For edge blocks, a minimum burn interval of 5 years was used as it reflects what is feasible for agencies to achieve while allowing fuel recovery after burning. For landscape blocks, the minimum burn interval is the minimum tolerable fire interval for the majority of the vegetation type within each block, as represented by NSW Department of Planning and Environment mapping. In each case study landscape, 1000 ignition locations were selected based on an empirical model developed and tested for similar forest types 56 . Individual fires were ignited at 11:00 h local time and propagated for 12 h, unless self-extinguished within this period. This time period provides a standardised approach for risk estimation 15 , 57 and was chosen as a compromise between a sufficient amount of time for significant wildfire impacts to be realised 58 , while avoiding the factorial multiplication of weather conditions spanning multiple days. We tested seven combinations of equal edge and landscape treatment (0, 1, 2, 3, 5, 10, 15% p.a.), resulting in a range of fuel age classes for each simulation (Supplementary Figures 7 –10). Half-hourly weather data was drawn from the full record of observations at the nearest Bureau of Meteorology automatic weather station for each case study landscape (Casino 1995–2014, Gloucester 1991–2014, Blue Mountains 1991–2014, Jervis Bay 2000–2014). Simulations were repeated for each of the fire danger categories that had been recorded during the fire season (Spring-Summer) in each case study landscape i.e. Low–Moderate (0–11), High (12–24), Very High (25–49), Severe (50–74), Extreme (75–99) and in Jervis Bay only, Catastrophic (100+). The results from the simulated fires were used to estimate the impact on five management values (see “ Impact estimation ” section below) and then adjusted for the frequency of fire weather conditions contributing to ignitions and fire spread to estimate annualised risk (see “ Risk estimation ” section below).

Two sets of simulations were run to explore the effect of 2019–2020 fire weather conditions on prescribed burning effectiveness: (1) with weather drawn from the long-term historical record of fire season observations, referred to as "control”, (2) with weather drawn only from the 2019–2020 fire season, referred to as “2019–2020”. For Casino the period of active fire in the 2019–2020 fire season was September 2019 to December 2019, for Gloucester and the Blue Mountains this was October 2019 to December 2019, and for Jervis Bay this was December 2019 to January 2020. The relative frequency of fire weather conditions in each scenario was incorporated into risk estimation through a Bayesian decision network (see “ Risk estimation ” section below).

Three sets of simulations were run to explore the trajectory of risk in the aftermath of 2019–2020 fire season: (1) with a fire history excluding the 2019–2020 fire season and with no prescribed burning, referred to as “control”, (2) with a fire history including the 2019–2020 fire season, and with prescribed burning and fuel accumulation through to 2021 i.e. 2 years after the 2019–2020 season (“2021”), and (3) the same as (2) except through to 2025 (“2025”). Due to the very large area burnt during the 2019–2020 season, prescribed burning treatment rates (edge and landscape) were capped at 5% p.a. for Casino, Gloucester and the Blue Mountains. In Jervis Bay, where 81% of the study area was burned by the 2019–2020 fires, edge treatment was capped at 5% p.a. and landscape treatment rate was capped at 1% p.a.

Impact estimation

Effectiveness of prescribed burning at mitigating wildfire impacts was assessed base on area burnt and four management values: house loss, loss of human life, length of powerline damaged and length of road damaged. Area burnt was a direct output from the fire behaviour simulations. The probability of house loss was calculated as a function of predicted ember density, flame length and convection as presented in 59 . House loss was calculated per 180-m model grid cell and then multiplied by the number of houses in that grid cell to estimate the number of houses lost per fire. Statistical loss of human life was based on house loss (using the house loss function), the number of houses exposed (using simulation output) and the number of people exposed to fire 60 . House location and population density data were derived from national datasets ( 61 , Australian Bureau of Statistics) and combined to give the total number of people exposed to fire. Road and powerline location data was supplied by the NSW Department of Planning and Environment. In the absence of empirical data a simple threshold of 10,000 kW/m was used to classify roads or powerlines within each 180-m grid cell as damaged by fire or not. Impacts were estimated from simulation output and the datasets described above, resulting in a distribution of area burnt and impacts on the four management values, corresponding to different weather, treatment and ignition scenarios.

Risk estimation

Building on previous studies 15 , 57 , a Bayesian Decision Networks (BDN) approach was used to generate residual risk estimates and hence evaluate the risk mitigation available from prescribed burning. We adopted the recommendations of Marcot et al. 62 and Chen and Pollino 63 in designing our BDN. A conceptual model was adapted from previous studies of fire management 64 and used to create an influence diagram. In this model fire weather affected ignition probability; fire weather and treatment option (a decision node) affected the distribution of fire sizes; and fire weather, fire size and fire management affected the amount of loss for a given management value. To translate the influence diagram into risk estimates, probability distribution tables were populated for the fire weather node (based on weather station data) and the fire size and management value impact nodes (based on the impact estimation step described above) of the BDN. The BDN then generated output values for each of the different prescribed burning treatment scenarios, based on the influence diagram.

Continuous data were discretised on a log scale across the range of values iteratively to get a relatively even distribution across non-zero values. For each FFDI category, we calculated the average maximum daily FFDI during the fire season for each study area, using the same weather station data used to drive PHOENIX. FFDI values were then separated into fire days (fire recorded within 200 km of the weather station) and non-fire days. The relative frequency of fire days was then used to drive ignitions in the BDN. Raw risk values were the expected node likelihoods for area burnt, house loss, life loss, length of powerline damaged and length of road damaged. These raw values were converted into residual risk values by dividing them by the risk value associated with the zero edge, zero landscape treatment scenario. These risks can be validly compared between regions because they reflect the observed distribution of fire weather conditions in each area. Further details of fire behaviour simulations, impact estimation and risk estimation can be found in 15 , 57 .

Data availability

The datasets generated from fire simulation and risk estimation for the current study are available from the corresponding author on reasonable request. Weather data is available from the Australian Bureau of Meteorology ( http://www.bom.gov.au ). Vegetation mapping and fuel accumulation models are available from the NSW Rural Fire Service ( https://www.rfs.nsw.gov.au ). Fire-sensitive vegetation, road and powerline location data is available from the NSW Department of Planning and Environment ( https://www.environment.nsw.gov.au ).

Code availability

Code to prepare the plots is available on request.

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Acknowledgements

We acknowledge the New South Wales Government's Department of Planning & Environment for providing funds to support this research via the NSW Bushfire Risk Management Research Hub. Thank you to the NSW Rural Fire Service and NSW Department of Planning and Environment for providing data. The authors declare no conflicts of interest.

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H.C.: conceptualisation, formal analysis, writing—original draft, visualization. B.C.: conceptualisation, software, investigation. T.P.: conceptualisation, methodology, writing—review and editing. O.P.: methodology, writing—review and editing. M.M.B.: methodology, writing—review and editing. R.B.: conceptualization, methodology, writing—review and editing.

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Clarke, H., Cirulis, B., Penman, T. et al. The 2019–2020 Australian forest fires are a harbinger of decreased prescribed burning effectiveness under rising extreme conditions. Sci Rep 12 , 11871 (2022). https://doi.org/10.1038/s41598-022-15262-y

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DOI : https://doi.org/10.1038/s41598-022-15262-y

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