A Brazilian study shows that the number of fires detected across the Amazon region between 2003 and 2020 was influenced more by uncontrolled human use of fire than by drought. According to the researchers, the burning of vegetation to prepare areas for grazing and deforestation rather than extreme water deficits was the main cause of fire in most years with a large number of fires.
On average, pastures and other agricultural lands accounted for 32% of the area burned annually in the Amazon, followed by natural grasslands with 29% and old-growth forests with 16%.
Of the nine countries with areas of Amazon rainforest, Brazil and Bolivia together accounted for most of the fires detected in the region each year, with more than half and around a third respectively.
The lion’s share of the Amazon is in Brazil (63%), but the lowland rainforest biome also extends into Bolivia, Colombia, Ecuador, Guyana, French Guiana, Peru , Suriname and Venezuela, each with between 9% and 6.5% of the total area, which is 6.67 million square kilometers.
An article on the study is published in a special issue of Global ecology and biogeography on the growing threat that fire poses to the world’s forests.
The authors are scientists affiliated with the Brazilian National Institute for Space Research (INPE), the National Center for Disaster Monitoring and Early Warning (CEMADEN), and the State University of Maranhão (UEMA).
The number of fires in the Brazilian Amazon is on the rise again. In the first nine months of 2022, especially in August and September, it was the highest since 2010, when 102,409 fires were detected, according to INPE. At the same time, since 2019, deforestation in the biome has reached the highest levels since 2009, exceeding 10,000 square kilometers per year. The trend continues, judging by the statistics available from DETER, INPE’s deforestation alert platform.
“The scientific literature on fire in the Amazon has tended to focus on the Brazilian part of the biome. We have extended the scope to other countries to determine where fire is most critical and deserves attention, especially in light of different lands. uses and types of ground cover. We concluded that fire is used in agriculture to renew vegetation, mainly in pastures and especially in Brazil, but without proper fire management, which increases the risk of fire escaping into adjacent forest. and causes forest fires,” said Marcus Vinicius de Freitas Silveira, a Ph.D. candidate for the Earth Observation and Geoinformatics Division (DIOTG) of INPE and first author of the article.
For Luiz Eduardo Oliveira and Cruz de Aragão, head of DIOTG-INPE and last author of the article, the study innovates by taking the entire Amazon as a perimeter and nearly 20 years of data. “By analyzing this long period, we were able to identify anomalies in the time series, such as 2020. The results show a diffusion of the use of fire throughout the Amazon, both for clearing and burning the forest. and for ongoing pasture management,” he said.
Aragão is the head of the Laboratory of Tropical Ecosystems and Environmental Sciences (TREES) and participates in FAPESP’s research program on global climate change (RPGCC).
As Aragão noted, 2020 is an “anomaly in the time series.” According to the study, environmental control operations in the region weakened in 2020, which followed the infamous 2019 Amazon fire season and was also a time when the COVID-19 pandemic increased.
In 2020, the total area burned in the Amazon was the largest since 2010, and the area burned by active fire was the second highest in the time series despite a much smaller area with an abnormally acute water deficit compared to the mega- 2015-16. drought, write the authors.
Another important Brazilian biome, the Pantanal – the largest wetlands in the world, with an area of 250,000 square kilometers, parts of which are in Argentina and Paraguay – was also devastated by an unprecedented fire in 2020. The water surface fell 34% more than the average year in 2020, according to an article published in July 2022. Besides Aragão, its authors include Liana Anderson, penultimate author of the article on the fire in the Amazon .
As in the tropical rainforest, the Pantanal fires were a consequence of increased human fire-related activities, with 70% occurring on rural properties, 5% on indigenous reservations and 10% in protected areas, according to the study.
For Anderson, the main short-term action required to reduce the risk of wildfires in the Amazon is to eradicate illegal deforestation in the region and tackle the problem of land grabbing. “At the same time, training and dissemination of fire-free land management techniques is essential to minimize the growing risk of major fires. The increasingly fragmented landscape and warmer climate with less rain lead to increased flammability,” she said.
Fires increased by 18% between January and September compared to the first nine months of 2021 in Maranhão, a Brazilian state located in the transition zone between the Amazon and the Cerrado, the country’s second biome and also threatened in various ways .
“As discussed in our article, recent fire activity in the region is closely linked to deforestation, which has increased due to weakening federal and state environmental controls,” said Celso Silva-Junior, affiliate of the State University of Maranhão (UEMA) and second author of the article.
Implications
Fire is one of the main types of disturbance responsible for the degradation of the Amazon, with negative impacts on the structure and dynamics of the forest, mainly because it alters the capacity of the forest to capture carbon and releases stored carbon.
The fire is also harming the health of people in the area by intensifying air pollution and increasing hospitalizations due to respiratory illnesses. According to a report produced by the Health Policy Research Institute (IEPS) in partnership with the Amazon Environmental Research Institute (IPAM) and Human Rights Watch, burns associated with deforestation in the Amazon led to 2,195 hospitalizations for treatment of respiratory illnesses in 2019. , with 49% involving people aged 60 or over and 21% involving babies up to one year old.
Smoke pollution from forest fires in the Amazon, added to the dirt already present in the air of major cities as well as low clouds, was responsible for turning day into night in São Paulo on August 19 2019, despite the distance of 2,700 km to be covered. Manaus, the capital of the state of Amazonas.
Data
In the most recent Global ecology and biogeography article, the researchers describe their analysis of time series for 2003-2020 compiled from records of active fires and burned areas, cross-referencing them with annual land use and cover data, measuring areas with abnormal levels of fire, drought and deforestation for each year, and identifying the spatial distribution of these anomalies in 2020, all based on a 10 km x 10 km grid covering the entire Amazon region.
The results showed that Brazil alone accounted for an average of 73% of annual active fire detections in the Amazon between 2003 and 2020, followed by Bolivia with 14.5% and Peru with 5.3%.
When the annual detections of active fires in each Amazon region were divided by the total area of the region, the authors found that the highest density occurred in Bolivia, with an average of six active fires per 100 kilometers. squares per year, followed by Brazil with three.
In Brazil and Bolivia, active fires peaked in the 2000s and then declined, bottoming out in 2013-14 and rising again thereafter.
Brazil contributed 56% of the total annual area burned in the Amazon on average over the entire period, while Bolivia’s share was 33%. Venezuela and Colombia each accounted for 4%. Although Peru was the third region in number of fires, it contributed only 0.63% of the total annual area burned on average.
Cropland and pasture, natural grassland, old-growth forest, and wetlands other than flooded forest were the land use and cover types that burned the most throughout the Amazon during the period. representing respectively 32%, 29%, 16% and 13% of the total annual area burned on average.
Agricultural land also accounted for the largest proportion of the total annual area burned in Brazil (48%) and Peru (51%). Ancient forests burned the most in Ecuador (76%), wetlands other than flooded forests in French Guiana (46.5%), and natural grasslands in other Amazon regions (40% or more).
“Fire is used to prepare areas for crops or pastures, but fire is a danger not only for the forest and its biodiversity, but also for the sustainability of agriculture itself,” Aragão said. “The solution would be to develop strategic land use planning at all levels of government and in all sectors of society, with training and assistance to use more advanced techniques.”
More information:
Marcus VF Silveira et al, Amazon fires in the 21st century: The year 2020 in evidence, Global ecology and biogeography (2022). DOI: 10.1111/geb.13577
Maria Lucia Ferreira Barbosa et al, Compound Impact of Land Use and Extreme Climate on the Brazilian Pantanal 2020 Fire Toll, Global ecology and biogeography (2022). DOI: 10.1111/geb.13563
Quote: Fire in the Amazon is more associated with agricultural burning and deforestation than drought (2022, November 4) Retrieved November 4, 2022 from https://phys.org/news/2022-11-amazon-agricultural- deforestation-drought.html