Deforestation in the Amazon Rainforest has become a major concern to climate scientists, who fear it may trigger a catastrophic savannization of the rainforest biome. This unique tropical ecosystem occupies 5.4 million square kilometers (2.1 million square miles) in central South America, and contains the largest assembly of plant and animal biodiversity on Earth. It features 40,000 species of plants including an estimated 16,000 species of trees. 1 2
The rainforest spreads across the Amazon Basin into nine different countries, although Brazil owns the greater part (60 percent). 3
Deforestation in Brazil’s Amazon rainforest increased by almost 30 percent, in the 12 months between August 2018 and July 2019. The main causes of this man-made destruction include cattle raising, logging, soybean cultivation, slash-and-burn farming, construction projects, and oil drilling.
Deforestation releases carbon into the atmosphere in the form of carbon dioxide, and accounts for about 10 percent of greenhouse gas emissions worldwide. Scientists warn that if it continues, it may trigger irreversible savannization of the rainforest which, over time, would see the latter transformed into grassland.
In addition, the continuing clearance of rainforest habitat will undoubtedly lead to a major loss of biodiversity in the animal and plant kingdoms, which Planet Earth can ill afford. See also: 10 Reasons Why Plants are Important.
For millennia, this relatively remote and impenetrable expanse of tropical jungle was largely left in peace, until the opening of the Trans-Amazonian highway in 1972 ushered in a new era of deforestation and exploitation. Today, because of international concerns about global warming, this unique biological community of plants, animals, insects and fishes, along with roughly 200,000 indigenous people, has become a battlefield in the struggle against climate change.
- Why Are Environmentalists So Concerned About Deforestation in the Amazon Rainforest?
- Disastrous Synergy Of Forces
- The Tipping Point To Disaster
- History of Deforestation in the Amazon
- Causes Of Deforestation in the Amazon Basin
- Rate Of Deforestation in the Amazon
- How Does Deforestation in the Amazon Rainforest Affect Climate Change?
Why Are Environmentalists So Concerned About Deforestation in the Amazon Rainforest?
The Amazon biome contains an estimated 390 billion trees, many of them primeval, old-growth trees, each capable of storing several tons of carbon. In all, the bioregion is thought to contain between 90 and 140 billion tons of carbon, 4 although other studies indicate that Amazon carbon storage is much higher, at roughly 150 to 200 billion tons. 5 For more on this, see: Which is the Largest Carbon Reservoir?
According to computerized climate models, if all, or most, of this carbon were to be released into the atmosphere by (say) a tragic combination of severe drought, deforestation and forest fire, its effect on greenhouse gas emissions would be catastrophic. According to Thomas Lovejoy, senior fellow at the United Nations Foundation and professor of environmental science at George Mason University, the world’s atmosphere holds about 415 parts per million (ppm) of carbon, and the destruction of the Amazon would add roughly 38 ppm. 5
Alarmingly, in recent years, there seems to be a cascade of severe events taking place within the Amazon Basin. These events include the three nasties: (1) drought (2) deforestation and (3) fire.
In 2005, parts of the Amazon rainforest suffered the worst drought in a century and indications showed that 2006 was just as parched. 6 Four years later, the Amazon basin experienced a third severe drought, in some aspects it was even more intense than the 2005 drought. Five years on, there were two more years of drought in 2015 and 2016. 7
- After thirty-five years of rising deforestation (1970-2005) the rate of deforestation (notably in the Brazilian rainforest) fell by almost 80 percent between 2005 and 2012, before moving upwards once more. 8 It rose roughly by almost 30 percent in 2013 9 and rose again in 2015.
- In the 12 months between August 2017 and July 2018, almost 8,000 square kilometres were deforested in Brazil – a 13 percent increase over the previous year. 10
- According to INPE, Brazil’s National Institute for Space Research, deforestation inside Brazil’s Amazon rainforest increased by 29.5 percent in the 12 months between August 2018 and July 2019 – the highest rate since 2008. During this period, the rainforest lost 9,762 sq km (2.4 million acres) of its vegetation. 11
3. Forest Fires
During the first eight months of 2019, the number of fires in the Amazon climbed to 156,000, the highest number since 2010, according to Global Forest Watch.
On 20 August 2019, INPE announced there had been an 84 percent increase in the number of fires in the Amazon rainforest compared with the same period in 2018. The fires destroyed more than 1,330 square miles of forest cover, a 39 percent rise year on year. INPE also reported an 88 percent increase in deforestation in June 2019, in comparison with the same period last year.
According to the Copernicus Atmosphere Monitoring Service (CAMS), the EU’s earth observation programme, the best way to assess how bad fires are, is to look at how much carbon dioxide is being emitted. So far, roughly 228 million tons of CO2 have been released – the highest amount since 2010. 12
Are the fires deliberate or accidental? Deliberate, says Yadvinder Malhi, Professor of Ecosystem Science at the University of Oxford. Almost all fires in humid forests are started by people. Alberto Setzer of INPE, agreed: 99 percent of the wildfires in the Amazon basin are a result of human actions, either on purpose or accidentally, he said. 13
According to Mikaela Weisse, a fellow at the World Resources Institute, the biggest gainers are cattle grazers and soybean growers. “Directly after deforestation, mostly what we see is pasture,” she said. Later, soybean growers take over the grazing lands.
Disastrous Synergy Of Forces
The temperature of the Earth is rising due to global warming. This dries the rainforest and causes droughts. This warming is accelerated by deforestation as it releases more CO2 into the atmosphere. Deforestation is also a major cause of droughts. 14 Fires – whether deliberately ignited to speed up the clearance process, or accidentally started because of dry conditions – then aggravate the whole process even further, by emitting more CO2 and weakening the rainforest’s ability to recover. This synergy of forces represents a major threat to the survival of the Amazonian ecosystem. See also: What is the Effect of Wood Burning on Climate Change?
The Tipping Point To Disaster
Studies indicate that deforestation in the Amazon rainforest may be nearing an irreversible tipping point, at which it would begin mutating into a drier type of ecosystem through a process known as savannization. 15 Such a transformation would lead to the wholesale loss of species and greatly accelerate global warming with incalculable consequences for the planet.
According to one analysis of the problems peculiar to the Amazon rainforest, although the tipping point that leads to irreversible change from rainforest to savanna is generally supposed to occur when 40 percent deforestation is reached (it currently stands at 17 percent), a combination of drought, deforestation, and fire might bring the whole process forward. 16
Carlos Nobre, the lead study author, later explained that because of the synergistic effect of drought, deforestation and fire, it is now sensible to conclude that the estimated tipping point is more likely to be reached after only 20-25 percent deforestation.
History of Deforestation in the Amazon
Up to the 1960s, much of the Amazon jungle remained intact due to lack of access. Furthermore, poor soil made plantation-based agriculture uneconomic. Despite attempts during the 1960s to introduce slash-and-burn agriculture it wasn’t until the introduction of the Trans-Amazonian Highway in 1972 that any real damage was done.
To boost the project, settlers were given 250-acre plots of land, cash as well as agricultural loans, in exchange for settling along the highway and converting the surrounding rainforest into agricultural land. These farmers, it was thought, would be supplying the domestic market with copious supplies of beans, rice and maize, as well as earning valuable hard currency through the export of coffee, cocoa and other crops.
For a few years, the settlers managed, and slash-and-burn agriculture increased dramatically, as did forest clearance. However, the highway proved unusable due to flooding for six months every year, leaving settlers isolated. Moreover, new forest had to be cleared continually to make up for poor yields and rampant soil erosion.
As a result, many settlers drifted away, but the forest continued to degrade. Other settlers were recruited to clear trees along roads for cattle ranches, because the soil could accommodate grass and ranching required little labor. Logging also grew as trees could now be transported to the coast by truck. Mining for gold and other minerals was also introduced. All this led to a dramatic jump in the annual rate of deforestation from 1991 to 2004, with up to 25,000 square kilometres of forest being lost in some years. 19
New government schemes – like the National Institute for Colonization and Agrarian Reform in Brazil (INCRA) – attracted 150,000 settlers into the Amazon, lured by the offer of land ownership after five years. In 1995, almost half of the deforestation in Brazil was caused by subsistence farmers clearing parcels of land no bigger than 125 acres.
After peaking at a loss of 27,000 square kilometers in 2004, deforestation slowed between 2005 and 2012. The decline was especially noticeable in the Brazilian Amazon, where deforestation rates decreased by 60 percent. 20 At the same time conservation areas were established amounting to roughly 1,000,000 square kilometers. In 2017, the Brazilian government joined the U.N. REDD and REDD+ programs (Reducing emissions from deforestation and forest degradation) in an attempt to limit deforestation.
Causes Of Deforestation in the Amazon Basin
Rainforest clearance within the Amazon biome is driven by land use change involving multinational corporations as well as local farmers. The main factors include: (1) Cattle raising. (2) Logging. (3) Soybean production. (4) Slash-and-burn farming. (5) Dam Construction. (6) Oil Drilling.
Forest removal to clear ground for cattle grazing has been a leading cause of deforestation in the Brazilian Amazon ever since the late-1960s. In 2004 a World Bank report blamed the cattle sector for 80 percent of all deforestation in the region. 21
This was followed in 2006 by a report issued by the Food and Agriculture Organization of the United Nations, which stated that 70 percent of formerly forested land in the Amazon, and 91 percent of land deforested since 1970, was being used for livestock grazing. 22
Unfortunately, cattle rearing is not an environmentally friendly activity. Not only is it a major driver of deforestation but the cattle themselves emit large amounts of methane gas – a powerful greenhouse gas – from their digestive system, thus giving a boost to global warming.
Logging for tropical hardwoods like mahogany and teak, as well as other exotic wood for furniture and so on, combined with the supply of regular wood for building materials, charcoal, and other wood products, is a multi-million-dollar business with substantial profits. Several types of expensive tropical hardwoods are imported by developed counties, just for coffins that are then buried or burned.
Charcoal-producing ovens are also big consumers of timber. In one month, police seized 800 illegal ovens in the municipality of Tailandia in the northern Brazilian state of Para. The ovens were estimated to use about 23,000 trees per month. 23
In theory, logging in the Amazon is very strictly controlled. In practice, 60-80 percent of all logging in Brazil is estimated to be illegal.
Brazil produces 96 million tons of soybeans, mainly for animal feed and biodiesel. It is the second-biggest producer in the world, after the United States. 24 Until 2006, soybean farming was a major cause of forest clearance in the Amazon. 25 However, in 2006, a private sector pact known as the Soy Moratorium was agreed to, whereby a number of commodity companies – including the $114 billion trading conglomerate Cargill – agreed not to purchase Amazonian soybeans grown in recently deforested areas. The agreement followed a 25 percent fall in soy prices, the previous year, and years of controversy concerning the amount of deforestation carried out by the soy industry.
However, while perhaps long overdue, the moratorium has been a major factor in reducing the deforestation associated with soy production in the bioregion. 26 Whether this type of agreement survives or whether it can be replicated in other industries, remains to be seen.
Slash-and-burn is a form of shifting cultivation whereby trees, bushes and forests are cleared by slashing and the remaining vegetation burnt. The ashes, which add potash to the soil, are spread over the land just before the rainy season. The seeds are then sown afterwards. Unfortunately, as reported above, the Amazon has poor soil. So, to maintain productivity, the cultivator has to move on and repeat the process with another plot.
Slash-and-burn methods have been used for millennia by subsistence farmers throughout the developing world, with no damage to the environment. So long as the land is allowed to recover, slash-and-burn remains a relatively sustainable method of farming.
However, when 150,000 temporary settlers start burning down millions of acres of forest in the space of a few months, the practice becomes completely unsustainable: not least, because of the huge surge in carbon dioxide emissions.
Since the 1970s slash-and-burn has been the principal method used to clear forest sites in the Amazon. According to one survey, there are an estimated 500,000 small farmers in Brazil alone, each of whom on average slashes and burns 2.5 acres of forest per year. 27
Hydroelectric dam projects in the Amazon are a growing cause of deforestation and greenhouse gas emissions. The reservoir of the Balbina dam, for instance, is estimated to have emitted 23 million tons of carbon dioxide and 138,000 tons of methane in its first three years of operation.
The gases are discharged by organic matter (plants, algae) that flows into, or is produced in, reservoirs over their lifespan. The gases are emitted at the reservoir surface, at turbines and spillways, and downstream of the dam. In addition, like all major construction projects, the Balbina dam would have required extensive deforestation for resettlement sites, transmission lines and access roads.
Another 150 dams are planned for the Amazon over the next two decades. 28
According to a study by the environmental group Amazon Watch, reported in the Guardian, oil drilling poses one of the most serious threats to the western region of the Amazon in Ecuador, Peru and Colombia. American refineries already process 230,293 barrels of Amazon crude oil a day (2015) but now Chinese oil companies are moving in to exploit proposed oil and natural gas fields covering 283,172 square miles of the Amazon. Anyone who knows anything about the greenhouse gas emissions produced by America’s own petroleum infrastructure of wells, pipelines and refineries, knows the global damage this development is likely to cause. On the ground it will simply lead to more and more deforestation. 29
Drilling by Ecuador’s state oil company PetroAmazonas recently began near the Yasuni national park – considered by botanists to be one of the most biologically rich places on Earth. Yasuni contains 655 species of trees – more than the US and Canada combined – as well as two of the last tribes in the world living in voluntary isolation.
Peru’s Amazon rainforest is already extensively contaminated from decades of oil and gas drilling, according to a report presented at the annual Goldschmidt geochemistry conference in Sacramento. Using data from Peruvian public agencies, oil companies and NGOs, including 4,480 samples from 10 major rivers, taken between 1983 and 2013, the study found that almost 70 percent of the river water samples exceeded Peru’s safe limits for lead, and 20 percent exceeded cadmium limits. 30
Rate Of Deforestation in the Amazon
Almost 1 million square kilometers of the Amazon tropical forests have already been deforested and another equal portion finds itself in the process of degradation. 31
In 2015, after a slowdown lasting several years, deforestation of the Amazon started rising again, mostly because of an increase in demand for palm oil and soy. 32
Between August 2017 and July 2018, 7,900 square kilometres (3,100 square miles) were deforested in Brazil – a 13.7 percent rise over the previous year and the largest area cleared since 2008.
In June 2019, deforestation in the Amazon rainforest in Brazil, rose more than 88 percent compared with the same month in 2018.
(a) Data from: Brazil’s National Space Research Institute (INPE) and MapBiomass, a collaboration of universities, NGOs and technology companies, to understand Brazilian territory changes based on the mapping of land cover and land use.
(b) Unlike INPE data, MapBiomas accounts for forest loss due to fire.
(c) 1970 comparison is a percentage of pre-1970 baseline.
How Does Deforestation in the Amazon Rainforest Affect Climate Change?
The effects of deforestation in the Amazon Basin impact global warming in two main ways. (1) The loss of trees leads to a reduction in CO2 absorption. (2) The burning of trees leads to the emission of carbon dioxide and other greenhouse gases. (3) The loss of forest canopy reduces the cooling power of the Amazon ecosystem.
Reduces CO2 Absorption
In the debate on climate change, it is unclear to what extent the Amazon is a net absorber of carbon dioxide (CO2). 33 But it is generally recognized that transforming a living rainforest into a dry expanse of savanna is bad for carbon emissions, because the amount of carbon that a tree takes in (via photosynthesis) over its lifespan is greater than the amount it transpires. At least one study has shown a clear net benefit. 34 Thus, the more trees felled by deforestation, the less CO2 is taken out of the atmosphere.
Ever since the Intergovernmental Panel on Climate Change (IPCC) produced a Special Report on Carbon Capture and Storage (CCS) in 2005, this technique of carbon dioxide removal has been seen as an essential part of any climate change mitigation strategy. Not surprisingly therefore – given that trees are the perfect carbon capture and storage system – scientists around the world are shocked at the Brazilian government’s willingness to see trees being cut down across Amazonia. Clearly the gravity of the global climate crisis cuts no ice with the authorities in Brazilia. (For more, see our article: Tree-Planting: The Answer to Global Warming?)
Emits More Greenhouse Gases
As we have shown, above, deforestation also leads to the production and emission of more greenhouse gases, notably CO2 and methane. This can happen in several ways.
First, when trees or plants die, they decompose – a process that happens much faster in warm, moist conditions. During decomposition their remains are broken down by microorganisms like fungi, who produce CO2 as waste.
Second, trees and plants also give off CO2 when burned. But in addition, burning forest biomass also gives off another greenhouse gas, known as nitrous oxide (N2O). The actual amounts emitted are small but N2O is 300 times more powerful at heat-trapping than carbon dioxide remains in the atmosphere for over 100 years. Furthermore, a burning tree may also emit methane, another greenhouse gas, which is about 30 times more powerful than CO2. Finally, wood combustion also produces large amounts of the poisonous gas carbon monoxide.
Third, deforestation is closely associated with cattle raising, and cattle emit methane via their digestive system. In fact, cattle and other ruminants (sheep, goats) account for 37 percent of all the methane emissions resulting from human activity. But see new developments in breeding lower-methane livestock. 35
In total, annual carbon dioxide emissions from deforestation in the tropics (2015-2017) averaged 4.8 billion tons per year. 36
Reduces Cooling Power Of the Amazon Ecosystem
The rainforest cools the earth in two ways. First, by forming clouds that reflect sunlight. Second, by creating a water cycle for which tree and plant evapotranspiration is a major driver.
The Amazon rainforest makes half of its own rainfall. The moisture recycles five to six times as the air mass moves over the continent from the Atlantic until the Andes. When it meets the Andes, the uplift causes major rainfall, filling up the Amazon river system, the greatest river system on Earth – which holds up to 20 percent of all the world’s river water.
The cycles work like this. Evaporation from the complex surfaces of the forest (plumes of moisture rise from the forest after a rainstorm) combined with heavy transpiration of the trees themselves, releases moisture into the air forming clouds which are then blown westwards by prevailing easterly winds coming in from the Atlantic. 37
The clouds reflect sunlight, thus helping to cool the region and reducing global warming. (For more, see: How Do Clouds Affect Climate?)
As the clouds stagger under the weight of the moisture coming up from the ground, they release some of their moisture as rain. The falling rain is washed downstream to the ocean where it evaporates into the air, repeating the cycle. All of which explains the term “rainforest”.
Deforestation in the Amazon Rainforest kills trees thus disrupting the water cycle. In the process it raises local surface temperatures by up to 3°C. 38
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- “Deforestation in Brazil has rocketed since Bolsonaro became president”. www.newscientist.com. 22 July 2019.
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- “Testing the Amazon savannization hypothesis: fire effects on invasion of a neotropical forest by native cerrado and exotic pasture grasses.” Divino V. Silvério, Paulo M. Brando, Jennifer K. Balch, Francis E. Putz, Daniel C. Nepstad, Claudinei Oliveira-Santos, Mercedes M. C. Bustamante. The Royal Society. June 5, 2013.
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- “Amazon forest to savannah tipping point could be far closer than thought.” Tom Lovejoy, Carlos Nobre. Mongabay. March 5, 2018.
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- “Brazil Crackdown on Loggers After Surge in Cutting.” Reel, Monte. Washington Post. 21 March 2008.
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- “Study shows Brazil’s Soy Moratorium still needed to preserve Amazon”. the University of Wisconsin-Madison News. Kelly April Tyrrell (January 22, 2015).
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- “Proliferation of Hydroelectric Dams in the Andean Amazon and Implications for Andes-Amazon Connectivity.” Matt Finer, Clinton N. Jenkins. PLOS ONE. 2012.
- “US drives rainforest destruction by importing Amazon oil, study finds.” The Guardian. Oliver Milman, 28 Sep 2016.
- “Oil Drilling Contaminated Western Amazon Rainforest, Study Confirms.” Becky Oskin. LiveScience. June 13, 2014.
- “Spatiotemporal patterns of tropical deforestation and forest degradation in response to the operation of the Tucurui hydroelectric dam in the Amazon basin.” Appl Geogr 63:1–8. Chen G, et al. (2015)
- “Amazon Deforestation, Once Tamed, now Comes Roaring Back.” Tabuchi, Hiroko, Rigby, Claire, and White, Jeremy. The New York Times. Feb 24, 2017.
- “Why the Amazon doesn’t really produce 20% of the world’s oxygen.” Katarina Zimmer. National Geographic. Aug 28, 2019.
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- “Rainforest-initiated wet season onset over the southern Amazon.” Jonathon S. Wright, Rong Fu, John R. Worden, Sudip Chakraborty, Nicholas E. Clinton, Camille Risi, Ying Sun, Lei Yin. PNAS August 8, 2017 114 (32) 8481-8486.
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