Threats to Tropical Rainforests

Tropical rainforests are disappearing at an alarming rate. Between 1990 and 2020, the world lost approximately 420 million hectares of forest — an area larger than the entire European Union. While deforestation has slowed in some regions, it has accelerated in others. This lesson examines the causes, rates and devastating impacts of tropical rainforest destruction, with a focus on the three countries losing the most forest: Brazil, Indonesia and the Democratic Republic of the Congo (DRC).

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Causes of Tropical Rainforest Deforestation

Deforestation is driven by a combination of economic, social and political factors. In almost every case, the underlying driver is the demand for land or resources from growing populations and expanding global markets.

1. Commercial Agriculture — Cattle Ranching

Cattle ranching is the single largest driver of deforestation in the Amazon, responsible for approximately 80% of all deforestation in Brazil. The process is straightforward:

1. Forest is cleared, usually by slash-and-burn methods (cutting trees and setting fire to the remaining vegetation)
2. The ash temporarily fertilises the soil
3. Grass is planted for cattle pasture
4. After 5–10 years, the soil is exhausted and the rancher moves to clear new forest
5. Brazil has approximately 215 million cattle — the largest commercial herd in the world
6. Much of the beef is exported to Europe, China and the Middle East

2. Commercial Agriculture — Palm Oil and Soy

• Palm oil is the most widely used vegetable oil in the world, found in approximately 50% of all supermarket products (food, cosmetics, cleaning products, biofuel). Indonesia and Malaysia produce 85% of the world's palm oil, and vast areas of rainforest in Borneo and Sumatra have been cleared for plantations.
• Soy production in Brazil has expanded massively, often into areas of former rainforest or cerrado (savanna). Brazil is the world's largest soy exporter, producing over 130 million tonnes per year. Soy is primarily used for animal feed in the global meat industry.

3. Logging

• Commercial logging targets valuable hardwood species like mahogany, teak and ebony. A single mahogany tree can be worth $10,000–$10,000–15,000 on the international market.
• Selective logging removes the most valuable trees, but the process of felling and extracting them damages surrounding trees — for every tree extracted, an estimated 10–30 surrounding trees are damaged.
• Illegal logging is a major problem, particularly in the DRC, Myanmar and Indonesia. The illegal timber trade is worth an estimated $50–150 billion per year globally.

4. Subsistence Farming

In the DRC and parts of South-East Asia, subsistence farmers clear small plots of forest using slash-and-burn techniques to grow crops for their families:

• The cleared plot is farmed for 2–3 years until soil fertility declines
• The farmer then moves to a new plot, allowing the old one to regenerate (this is called shifting cultivation)
• Traditionally, this was sustainable because population densities were low and forests had time to recover
• However, growing populations mean shorter fallow periods, preventing full forest recovery

5. Road Building

Roads are the arteries of deforestation. Once a road is built into previously inaccessible forest, settlers, loggers and farmers follow:

• The Trans-Amazonian Highway (BR-230), built in the 1970s, opened up vast areas of the Amazon to colonisation
• In a pattern known as "fishbone deforestation", secondary roads branch off the main highway, with settlers clearing forest on either side
• Satellite imagery shows that 95% of deforestation in the Amazon occurs within 5.5 km of a road

6. Mining

• The Amazon contains vast mineral deposits including iron ore, gold, bauxite (aluminium), manganese and tin
• The Carajás Mine in the Brazilian Amazon is the world's largest iron ore mine, covering an area of 900 km²
• Mining not only destroys the forest directly but causes secondary damage through pollution of rivers with heavy metals (mercury from gold mining), sedimentation and road building

7. Hydroelectric Power

• Brazil's Belo Monte Dam on the Xingu River (a tributary of the Amazon) flooded approximately 500 km² of forest
• While hydroelectric power is renewable, the reservoirs created by large dams destroy vast areas of forest and displace indigenous communities

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Rates of Deforestation: Key Statistics

Country	Forest Area Lost (2001–2022)	Key Drivers	Current Trend
Brazil	~50 million hectares	Cattle ranching, soy, logging, mining	Accelerated 2019–2022 under Bolsonaro; declining since 2023 under Lula
Indonesia	~28 million hectares	Palm oil, logging, paper/pulp industry	Slowing due to moratorium on new concessions (since 2011)
DRC	~15 million hectares	Subsistence farming, charcoal production, logging, mining	Accelerating — now has the highest rate of primary forest loss

Exam Tip: Learn specific statistics for at least two countries. In Paper 3, you may be given data about deforestation rates and asked to compare or evaluate. Having your own statistics to add to the pre-released material will strengthen your answers.

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Impacts of Tropical Rainforest Deforestation

The impacts of deforestation are far-reaching, affecting local communities, national economies and the global climate.

Environmental Impacts

Carbon release and climate change: Tropical forests store an estimated 250 billion tonnes of carbon. When trees are cut and burned, this carbon is released as CO₂. Deforestation accounts for approximately 10% of global greenhouse gas emissions — more than the entire global transport sector.

graph TD
    A["Deforestation"] --> B["Trees burned/decompose"]
    B --> C["CO₂ released to atmosphere"]
    C --> D["Enhanced greenhouse effect"]
    D --> E["Global temperatures rise"]
    E --> F["Reduced rainfall in Amazon"]
    F --> G["More trees die from drought"]
    G --> A
    style A fill:#ff6666
    style G fill:#ff6666

This diagram shows the dangerous positive feedback loop — deforestation leads to climate change, which leads to drought, which kills more trees, releasing more carbon.

Biodiversity loss: Deforestation destroys habitats, pushing species towards extinction. Scientists estimate that 137 species are driven to extinction every day due to tropical deforestation. The orangutan in Borneo and Sumatra has lost over 80% of its habitat in the last 20 years due to palm oil expansion. Fewer than 100,000 orangutans remain in the wild.

Soil erosion: Without tree roots to bind the soil and the canopy to intercept rainfall, heavy tropical rains wash away the thin topsoil. This leads to:

• Gully erosion on deforested slopes
• Sedimentation of rivers, reducing water quality and damaging aquatic ecosystems
• Reduced soil fertility, making it harder to grow crops on cleared land
• Increased flood risk as water runs off the surface rather than being absorbed

Disruption of the water cycle: Trees return water to the atmosphere through transpiration. The Amazon generates 50–75% of its own rainfall through transpiration. Large-scale deforestation reduces this recycling, potentially leading to a "tipping point" where the Amazon becomes too dry to sustain itself and transitions to savanna grassland. Scientists estimate this tipping point could be reached if 20–25% of the Amazon is deforested — current deforestation stands at approximately 17%.

Social Impacts

Displacement of indigenous peoples: There are an estimated 1 million indigenous people living in the Amazon, belonging to over 400 different groups. Deforestation destroys their homes, food sources and sacred sites. Many have been forcibly relocated or have experienced violence from loggers, miners and ranchers. In the DRC, Pygmy communities (such as the Mbuti and Batwa) have been displaced by logging and mining.

Loss of traditional knowledge: Indigenous peoples possess centuries of accumulated knowledge about medicinal plants, sustainable farming and forest management. When communities are displaced, this knowledge is lost.

Conflict: Competition for land and resources between indigenous communities, settlers, ranchers and mining companies has led to violent conflict. In Brazil, dozens of indigenous leaders and environmental activists have been killed in disputes over Amazon land.

Economic Impacts

Short-term gains: Deforestation provides short-term economic benefits — timber sales, cattle ranching profits, mineral extraction revenue, and employment. Brazil's beef industry is worth approximately $8 billion per year in exports.