Tropical Rainforest - Amazon

Amazon Rainforest Location:

• The Amazon Rainforest is located in South America, within the Amazon River basin

• It spans 8 countries, mainly Brazil (≈60%), but also Peru, Colombia, Bolivia, Ecuador, Venezuela, Guyana and Suriname

• Covers approximately 5.5 million km², around 40% of the South American continent

• Located near the Equator, giving it a hot, wet tropical climate

Global & Environmental Importance

• Contains around 20% of the world’s biodiversity, including:

• ~40,000 plant species

• ~1,300 bird species

• Millions of insect species

• Acts as a major carbon sink, absorbing large amounts of CO₂ and helping regulate global climate

• Plays a key role in the water cycle through high rates of transpiration, contributing to rainfall locally and globally

• Often referred to as the “lungs of the Earth” due to its role in gas exchange

• It is also home to many indigenous tribes (20 million people)

• Contributes to Brazil’s NEE economy

Commercial Farming:

• Around 70–75% of deforested land in the Amazon is used for cattle grazing

• Forest is cut and burned to create pasture for beef production

• 200 million cattle and about 450 000 km^2 of pasture

• Driven by global demand for cheap beef, particularly from countries like China

• Forest cleared -> land use for cattle -> soil becomes infertile -> more forest cleared

Soy Production: 

• Large areas cleared for soybean farming, especially in Mato Grosso

• Mato Grosso experienced around 43% of rainforest loss during expansion

• Soy is mainly exported for animal feed in global markets

• Forest Cleared -> Monoculture Farming -> Soil Degradation -> Expansion and damage of new areas

Subsistence Farming

• Small-scale farmers clear land using slash and burn techniques

• Land is farmed until nutrients are exhausted, then farmers move on

• Less significant than commercial farming but still contributes to deforestation

• Forest burned -> short-term fertile soil -> nutrients quickly depleted -> further clearing

Road Building

• Major roads include the Trans-Amazonian Highway (4000km) and BR-163 (1700 km)

• Roads open up previously inaccessible forest areas

• Creates a “fishbone pattern” of deforestation spreading from roads

 Roads built → access increases → settlement, farming and mining expand

Logging 

• Brazil exports valuable hardwoods such as mahogany and teak

• Includes both legal and illegal logging

• Even selective logging damages surrounding trees and creates access routes

• Trees removed → roads built → increased access → further deforestation

Mineral Extraction

• Amazon is rich in minerals such as iron ore, gold, bauxite and copper

• Example: Carajás Mine (one of the world’s largest iron ore mines)

• 7.2 billion tonnes of iron ore reserves

• 300 million tonnes per year in peak production

• Mining requires forest clearance and causes river pollution

• Land cleared → mining infrastructure built → settlements grow → more deforestation

Energy Development (Hydroelectric Power)

• Example: Belo Monte Dam (~11,000 MW capacity) -> 18700 direct jobs 25k indirect jobs flooding causes vegetation to decompose and release methane

• One of largest dams -> flooding around 400km^2 of rainforest

• 20000 people were displaced and affected Arara indigenous people

• Brought 100000 migrants in

• Large areas of rainforest are flooded to create reservoirs

• Around 20,000 people displaced

• Forest flooded → habitats destroyed → infrastructure increases access → further development

Settlement/Population Growth

• Government encouraged migration to the Amazon to reduce pressure in cities

• Rapid growth of towns such as Parauapebas

• Amazon population grew by ~23% between 2000–2010

• Increased demand for land, food and resources

Soil Erosion

• Tropical rainforest soils are thin and nutrient-poor, with most nutrients stored in vegetation - Brazil loses about 100 tonnes of topsoil every year

• When trees are removed, soil is exposed to heavy rainfall, leading to rapid erosion and leaching

• Soil quickly becomes infertile, making land unsuitable for farming

•  Trees removed → no root binding → heavy rain washes nutrients away → soil degraded → more land cleared

Climate Change

• The Amazon acts as a major carbon sink, absorbing large amounts of CO₂

• Deforestation releases CO₂ through burning and decomposition of trees

• Reduces the rainforest’s ability to absorb carbon → contributes to global warming

• Trees removed → less CO₂ absorbed + more released → enhanced greenhouse effect → climate change

Disruption of Water Cycle

• Trees release water vapour through transpiration, contributing to rainfall

• Deforestation reduces transpiration → leads to reduced rainfall and drier conditions

• This can affect agriculture and increase risk of droughts

• Fewer trees → less transpiration → less rainfall → drier climate

• Economic Benefits (Short Term)

• Creates jobs (farming, mining, logging, construction)

• Generates income and exports (beef, soy, iron ore)

• Improves infrastructure (roads, energy like Belo Monte Dam)

• Helps Brazil develop as an NEE

• $600 million of beef and second largest exporter of soy beans

• Economic Costs (Long Term)

• Soil becomes infertile → farming declines → loss of income

• Loss of rainforest reduces future resources (timber, medicines)

• Damage to ecosystem services (e.g. climate regulation) can affect global economies

• Unsustainable → limits long-term economic growth

• This shows that the benefits are mainly short-term while the costs are long term