Case Study 4: Challenges and Recommendations for sustainable management of the Amazon Rainforest
This report by Amazonia Inc. highlights the adverse environmental effects of human activities on the Amazon Rainforest today to President Bolsanaro of the Social Liberty Party of Brazil. I am the Environmental Scientist, with 25 years’ experience in this field, and I am reviewing the harmful environmental effects caused by mining on the Amazon Rainforest, its ecosystem and its climate, focusing on Brazil. My colleagues of Amazonia Inc. will address other aspects of this. Dylan O’Flynn is the Ethicist, Cian O’Reilly is the Economist, and Connor MacAndrew is the Environmental Remediation Solutions Expert.
The Amazon Rainforest plays a critical role in nature today. It is home to a huge range of biodiversity including plants, animals and indigenous humans. It acts as a carbon sink and is vital to regulate global atmospheric composition, as the plants of the Amazon store billions of tons of carbon through photosynthesis, whereby they filter the air of carbon dioxide, replacing it with oxygen and water vapour (Withgoff et al., 2015). It provides natural resources such as fuel, medicine and research opportunities. Local communities especially depend on the multiple resources the Amazon Rainforest can provide for survival. The highest percentage of area of Amazon Rainforest is in Brazil (Butler, 2012). The Amazon Rainforest has been around for at least 55 million years since the Cretaceous period (Daily Facts Daily, 2016) (Malhi et al., 2008).
Mining in Brazil is one of the anthropogenic activities that is causing deforestation of the Amazon Rainforest. Mining has been on the rise for many years in Brazil, especially in the Amazon Rainforest region. Minerals which are being mined for include gold, copper, diamonds and other precious metals. Mining for these materials is conducted by both large-scale mining companies and small-scale ‘unofficial’ miners (Butler 2012). Carajas in Brazil is the world’s largest iron ore mining operation and Trombetas is the largest bauxite mining operation in Brazil (Sonter et al. 2017). There has been ten times the number of small-scale miners in Brazil in 2010 than in 1990, with over 200,000 operating in the Brazilian Amazon, due to the price of gold rising. The Tapajos-Xingu region has the brunt of this mining (Erickson-Davis, 2015). Gold is a mineral which is extensively mined for in the Brazilian Amazon Rainforest, due to rising prices of gold globally (Erickson-Davis, 2015). 1680km2 of Amazon rainforest was deforested between 2001 – 2013 across South America due to gold mining alone. 90% of this deforestation occurred across four ‘hotspots’, with 11% (183km2 loss of forest) of this occurring in the Tapajos-Xingu tropical rainforest region in Brazil (Alvarez-Borrios et al., 2015). This region has seen an increase of thousands of small-scale gold miners since 2008, with up to 5000 new miners in the municipality of Itaituba (O Globo, 2013) (Alvarez-Borrios et al., 2015).
2.1.2 Off-Lease Mining
Mining in Brazil occurs on designated mining sites; however, illegal mining also occurs outside of lease boundaries, which is relatively unaccounted for by the government. Deforestation due to mining occurs both inside and outside of leased mining areas. From 2005 to 2015, 11,670 km2 of Amazon forest in Brazil was lost to deforestation outside of leased mining areas due to mining (Sonter et al., 2017). This affected areas up to 70km outside of areas leased for mining (Sonter et al., 2017). This massive loss of forest accounts for 9% of forest lost in the Amazon in this time period, which is 12 times more deforestation than occurred within leased mining areas (Sonter et al., 2017). Mining in the Amazon has knock on affects that cause this deforestation outside of lease areas, such as (Sonter et al., 2017):
- Expanding urban areas for the mining employees
- Construction of infrastructure for mines (e.g. roads, housing)
- Development of supply chains for the minerals which are mined
- Constructing infrastructure due to fear of waste discharging into surrounding environment
Even though Brazil has reduced annual deforestation rates by 80% (Nepstad et al., 2009) by implementing policy interventions and economic conditions to fight deforestation, 127,000km2 of forest has been lost to deforestation since 2005 (Valeriano, 2007). Most of the deforestation due to mining occurred outside mining lease areas, in areas up to 70km which the study refers to as buffer zones. The deforestation in these areas are generally more extensive than inside lease areas, as these areas are not regulated. The level of mining in Brazil is continually increasing, which is worrying as Brazil has the largest extent of Tropical Amazon Rainforest in all South America, and largest area of Tropical Rainforest globally (Sonter et al., 2017).
2.1.3 On-lease Mining
60% of all regulated mining in Brazil is in the Amazon, covering an area of land of over 1.65 million km2 (DNPM, 2012). Deforestation did not occur as extensively in lease areas; however, it is still a problem. 14% of forest within lease areas was lost to deforestation between 2005 – 2015. Therefore, 983km2 of 6880km2 of forest was deforested. The total area of land deforested between 2005 – 2015, including lease areas and their 70km buffer zones, equalled 37,830km2 from 337,690km2. 31% (11,670km2) of this deforestation was caused by mining alone (Sonter et al., 2017).
2.2.1 Habitat loss
Mining directly and indirectly causes deforestation. Generally, desired minerals only make up a fraction of rock, therefore large amounts of rock in the target area must be disposed of. Considerable areas of land are thereby disturbed. Open pit mining is a common mining technique used in the Brazilian Amazon Rainforest, where a large hole is dug in the ground to remove the waste materials and desired minerals. This leads to huge habitat loss for native animals, plants and indigenous people, as well as degrading the aesthetic nature of the region (Withgoff et al., 2015). Infrastructure such as roads built to transport material to and from mines is also a cause of deforestation, and loss of biodiversity. An example of this is the 890km-long railway road developed by the mining company in Carajas, Brazil for transporting iron ore material to the deep-water-port (Ponta da Madeira) in Sao Luis, Maranhao (Sonter et al., 2017).
2.2.2 Forest Fragmentation
Indirect habitat and species loss are another problem due to forest fragmentation (Withgoff et al., 2015). This is shown in an experiment by Dr. Thomas Lovejoy in the Biological Dynamics of Forest Fragments Project, beginning in 1970 (Withgoff et al., 2015). This applied island biogeography theory to assess the impact of forest fragmentation on the remaining forest and its biodiversity. Ranchers could clear forest within study zones for cattle pastures but had to leave “square” fragments of forest untouched and fence these areas to keep cattle out. 11 “Islands” of isolated forest fragments of different sizes were left and compared to 12 fragments of forest that were established within continuous forest as controls. The study showed that:
- Smaller forest fragments lost more species than larger forest fragments
- Smaller forest fragments lost species faster than larger forest fragments
- Forest fragments need to be 1000 times bigger, to slow down species loss by 10 times
This is due to animals such as monkeys needing large ranges to survive, as well as army ants and types of birds. Organisms adapted to deep interior forests will not relocate to other areas of forest fragment, even over small gaps in land between forest fragments, leading to their demise. This study also showed that as ‘corridors’ of forest regrew, connecting fragments, foreign species to various areas who are adapted to disturbed areas of forest invaded new forest fragments, replacing the native species. The loss of forest and forest biodiversity is due to deep interior forest which are used to a dark, wet and windless environment, now being exposed to sunlight and strong winds (Withgoff et al., 2015). The construction of roads and urban developments for the influx of people due to mining cause forest fragments to occur which contain “edges”, which expose trees and wildlife to ‘edge conditions’, which they are not suited for; therefore, killing them (Withgoff et al., 2015).
- Impact on Ecosystem
The Brazilian Tropical Amazon Rainforest has very high biodiversity and has more variety of species of animals and plants than any other biome globally (Withgoff et al., 2015). This biodiversity relies on the native plants to supply its nutrients, because its soils are acidic, have poor fertility and are low in organic matter (Withgoff et al., 2015). Leaves and branches of the leaf litter fall and nourish the soil. Many soil organisms also help to decompose this fallen material and cycle nutrients within the biome. The soils low pH (high acidity) and low amount of organic matter means that cation exchange is very low (Withgoff et al., 2015). Cation exchange is needed for plant growth and needs low acidity and high organic matter to work. Cations (positively charged ions) such as calcium, magnesium and potassium are held onto soil by negatively charged soil particles (anions) (Withgoff et al., 2015), due to ionic bonding where opposite charges attract each other (Chemistry Libre Text, 2018). Plant roots then donate hydrogen cations to the soil in exchange for these cation nutrients. The soil then replenishes these cations via exchange with soil water. However due to the high acidic soil and low organic matter of the Brazilian Tropical Amazon Rainforest this cation exchange is not possible, hence the reliance on plants for nutrients. The low acidity of the soil and the absence of cation exchange causes nutrients to leach away, and harmful ions such as aluminium ions may be supplied to plants which damages them. This causes a constant cycle of deforestation because as rainforest is cleared for mining, logging and agriculture, the biome is left without any plants for nutrients. The soil itself cannot support agriculture for long, therefore cattle pastures and land for crops is used only for a short period of time, before farmers move off to new land where they will again clear tropical rainforest and cause deforestation and loss of biodiversity. (Withgoff et al., 2015).
Figure 1 Cation Exchange in Soil (Franklin Soil Fertility, 2014)
3.1.2 Aquatic Life
Open-pit mining is common in the Brazilian Tropical Amazon Rainforest, as it is often used for gold mining (Withgoff et al., 2015). It involves digging a huge hole and removing the desired minerals, as well as waste. Chemical contamination is a negative environmental impact caused by open-pit mining (Withgoff et al., 2015). This is caused by acid drainage, where water runs off the waste heaps or collects in the giant pits of the mine once it is abandoned (Withgoff et al., 2015). This becomes acidic as water and oxygen react with sulphides from the ore and produce sulphuric acid and can harm the wildlife of the surrounding environment by spreading through the region and permeate into aquifers, therefore, contaminating waterways (Withgoff et al., 2015). Abandoned open-pit mines can be filled with clay and soil and planted with vegetation to mitigate this; however, these mines can continue to leach acid for hundreds or thousands of years (Withgoff et al., 2015). Gold mining also causes pollution of arsenic, cyanide and mercury to air, soil and water (Eisler, 2004) (Veiga et al., 2006). Pollutants and sediments can also travel long distances along waterways from gold mining activities, adversely affecting wildlife and humans (Uryu et al. 2001). For example, environmental and ecological effects of metal minerals such as copper and zinc have been found up to 50km from mines due to mining (Duran et al., 2013). Elevated mercury levels in humans have been found hundreds of km from mining sites (Ashe, 2012). Mercury ends up in rivers due to its use in amalgamation in gold mining (Nevado et al., 2010). Small-scale, illegal minors, are inefficient with their mercury use, releasing approximately 1.32kg of mercury for every 1kg of gold produced (Butler, 2012). Mercury can be methylated into methylmercury (Butler, 2012) which is the most toxic and most commonly formed organic compound (Nevado et al., 2010). It is found in the Tapajos Amazon River Basin, Brazil which has the largest small-scale miner rate in South America (Nevado et al., 2010). Methylmercury is bio accumulative and biomagnified through the aquatic trophic chain; therefore, is toxic to small aquatic life, all the way up the food chain to humans (Nevado et al., 2010).
- Climate Change
The Amazon Rainforest is a global atmospheric carbon sink, storing billions of tons of carbon (Butler, 2012). The Amazon Rainforest help to regulate atmospheric carbon through photosynthesis, where leaves of plants use sunlight, water and CO2 to produce their own food (Withgoff et al., 2015). This releases O2 into the atmosphere and reduces CO2 in atmosphere, as seen in the following reaction: 6CO2 + 12H2O + sunlight → C6H12O6 + 6CO2 + 6H2O (Withgoff et al., 2015). Deforestation in the Amazon Rainforest contributes massively to global greenhouse gas emissions, due to the lack of plants conducting photosynthesis (Butler, 2012). Brazil has been the global leader in deforestation in recent decades, clearing 19500km2/year on average from 1996 – 2005, releasing 0.7 – 1.4 Gt CO2 e/year (Nepstad et al., 2009). The Amazon has warmed by about 0.25°C/decade in recent decades, however, temperature is projected to rise by 3.3°C this century (Mahli et al., 2008). This is a very significant rise and is largely contributed to by Amazon deforestation. Risk of drought is a huge possibility due to this (Mahi et al., 2008).
Figure 2 Photosynthesis (Withgoff et al., 2015)
It would be unethical and unwise for us as humans to deforest and degrade the Amazon Rainforest anthropogenically, after it survived for so many millions of years naturally without human intervention. There are many factors causing deforestation, negative impacts on the ecosystem, and climate change in the Brazilian Amazon Rainforest. This destroys vast ecosystems, degrades habitats for wildlife, and displaces indigenous humans. Global climate change is contributed to significantly by Amazon deforestation, with less plant and tree life in the Amazon Rainforest to regulate atmospheric composition. Action must be taken by the government to prevent this. Possible solutions for environmental remediation will be reported by my Amazonia Inc. colleague, Connor MacAndrew.
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