Human Impacts on a Tropical Rainforest
- Human activity within tropical rainforests (TRF) is widespread, with both global and local impacts
- Deforestation is the main threat to TRFs, and involves conversion of forest land to farms, ranches, or urban use
- Deforestation also results from mining and HEP projects
- Impacts of deforestation can be group as economic, social and environmental
Causes and Impacts of TRF Deforestation
Cause | Details & Impact | Example |
Mining of minerals - gold, copper etc. |
Large-scale deforestation which strips the soil and exposed to erosion Opencast mining is the cheapest but most environmentally damaging Water is clogged with silt, leading to downstream flooding |
Carajas in northern Brazil |
Agricultural uses |
Slash and burn to create pasture for cattle ranching, soil is exposed to erosion and increased leaching Commercial farming Single cash crops such as soy |
Brazils cattle ranching is extensive Clearing forestry for soy farms in Borneo, have destroyed so much of the orangutans habitat that they are now on the REDD extremely endangered list |
Selective logging |
Valuable hardwoods are chopped down, but as they fall, they damage surrounding trees and habitats Destructive clear-felling exposes the ground to erosion and decimates habitats and species |
HDE demands for furniture and building materials, encourages felling in TRFs as a reliable source of income Japan accounts for 11million m³ of TRF hardwood a year |
Road construction |
Highways connect areas within the forest which supports further TRF development Allows for ease of access for people and raw materials Large strips of land is cleared across the rainforest which destroys habitats |
Trans Amazonian Highway extends over 6000 km into the Amazon forest |
Electricity |
Construction of large dams for hydroelectric power to provide cheap energy Reservoirs for dams flood large areas of cleared forest Displacement of people, animals and destruction of habitats Poor construction of dams leads to failures and devastating flooding |
HEP Tucurui Dam supplies power to the Carajas mine |
Settlement growth |
Population pressures comes from natural growth and inward migration Brazil has an issue with landless people that need homes and relocation |
Internal migration from the poorest parts of Brazil is encouraged and land allows individuals to grow food and wood is used for fuel, which reduces overcrowding in other parts of the country |
Global impacts
- Burning releases CO2 into the atmosphere
- Forests in the Congo and the Amazon are some of the world's largest carbon stores
- Forest store up to 100 times more carbon than fields
- 75% of Brazil's carbon emissions come from deforestation
- More than 1.5 billion tones of CO2 are released due to deforestation
Economic, environmental and social impacts
Economic | Environmental | Social |
Brazilian government gains much needed income | Loss of habitat and biodiversity. Without tree canopy to intercept rainfall or roots to bind soil, more nutrients are washed away and increases the risk of flooding and mass movement | Dilution of culture due to increased contact with TNCs |
TNCs are the main winners on export of goods from the forest | Increases CO2 levels globally leading to increased global warming | Loss of home and increased spread of diseases |
Local people can get some employment and have benefitted from education | HEP dams destroy large hectares of forest and displace local tribes and destroy habitats due to flooding. | Improved education and access to major towns and cities. Improved general health care |
Reduction in available resources over time | Evapotranspiration is reduced, this reduces water vapour and eventually rainfall is reduced - edges of Amazon rainforest are becoming savanna like | Conflict between stakeholders over use of land |