Hazards Case Studies Flashcards
Describe the geographical significance of the Amazon Rainforest.
The Amazon Rainforest is the largest tropical rainforest on Earth, covering about 40% of the South American continent and spanning 8 countries. It is home to over 60,000 plant species and 20% of all known species on Earth. It covers roughly 5.5 million km² and contains around 390 billion individual trees across 16,000 species.
Why did the Amazon Rainforest gain public attention in the 1980s?
It gained attention due to a statistic showing an area the size of Belgium was being cut down and burned each year. Deforestation continues today, with around 20% of the Amazon already lost.
What role does the Amazon play in the carbon cycle?
The Amazon stores 17% of global terrestrial carbon, acting as a major carbon sink, which helps reduce global warming by lowering greenhouse gas levels. It absorbs 2.2 billion tonnes of carbon annually but emits 1.9 billion tonnes through dead trees, suggesting it’s becoming less effective.
Where is carbon stored in the Amazon Rainforest ecosystem?
Carbon is stored in biomass and soils. An estimated 100 billion metric tonnes of carbon are stored in Amazonian vegetation.
Describe the characteristics of the Amazon Rainforest’s water cycle.
The basin is drained by the Amazon River, discharging ~175,000 m³/s. Average annual rainfall is around 2,300 mm, sometimes exceeding 6,000 mm. However, only one-third is discharged; up to 50–80% of rainfall is re-evaporated or intercepted, contributing to cloud formation and global moisture distribution.
How does deforestation affect rainfall and the water cycle in the Amazon?
Deforestation reduces moisture recycling, leading to lower rainfall and more frequent droughts. About 25–35% of rainfall is due to forest evapotranspiration. Removing trees disrupts this cycle, decreasing atmospheric moisture and rainfall.
What are the main causes of deforestation in the Amazon?
Agriculture: For crops like soya and palm oil or cattle grazing.
Logging: Both selective (e.g., mahogany) and clear-cutting for timber and pulp.
Road building: For example, the Trans-Amazonian Highway and BR-163 make untouched forests accessible.
Mineral extraction: Mining for iron, nickel, tin, bauxite, gold, etc.
Settlement/population growth: New towns like Parauapebas have expanded rapidly, replacing forest with shanty towns.
What is the impact of deforestation on the water and energy balance in the Amazon?
In Mato Grosso, evapotranspiration fell from 50 km³/year (2000) to 40 km³/year (2009). Croplands and pastures have higher albedo and less evapotranspiration, disrupting rainfall. About 67.6% of rainfall is returned to the atmosphere through evapotranspiration.
How has deforestation affected seasonal rainfall in Rondônia?
Since the 1970s, the rainy season has been delayed by 18 days due to deforestation. Fires from deforestation release aerosols that inhibit rainfall, especially in the dry season, causing feedback loops that intensify droughts.
How does deforestation in the Amazon contribute to global climate change?
Deforestation and degradation turn the Amazon from a carbon sink into a carbon source. Around 30% of human emissions come from rainforest burning. Disturbed forests store 40% less carbon.
What are the predicted climate change impacts on the Amazon ecosystem?
Species migration and biodiversity loss.
Disrupted aquatic ecosystems due to warmer waters and less rainfall.
Increased invasive species and habitat loss in drier conditions.
Lower nutrient flow in rivers.
Sea level rise (~5 mm/year) threatening lowlands and mangroves.
How does deforestation affect Amazonian soils?
Tree removal leads to soil drying and higher temperature extremes. About 66.9 PgC is stored in the top 0.3 m of soil, which is highly vulnerable to erosion, burning, and decomposition post-deforestation.
What are the effects of deforestation on the Amazon’s river systems?
Less interception → more erosion and flash floods.
More droughts → increased wildfire risk.
Sediment runoff → altered river channels and disrupted transport.
Water supply issues in Brazilian towns and cities.
What is REDD+ and how is it used in the Amazon?
REDD+ is a UN initiative offering financial incentives to reduce emissions from deforestation. Brazil has received over $1 billion in payments for emission reductions and forest protection.
How has political involvement influenced Amazon deforestation?
Policies like the Forest Code and DETER (satellite monitoring) have reduced deforestation, but progress is fragile. Leadership changes can reverse environmental policies, leading to deforestation spikes under less environmentally focused administrations.
How do conservation areas help protect the Amazon?
Over 44% of the Brazilian Amazon is protected through indigenous territories and conservation units. These restrict deforestation activities like logging, mining, and agriculture, helping preserve forest cover.
What is agroforestry and why is it important in the Amazon?
Agroforestry combines agriculture and forestry to maintain biodiversity, sequester carbon, and support local livelihoods. Examples include shade-grown coffee and tree-integrated pastures, which are more sustainable than traditional land use.
How do ecotourism and sustainable livelihoods help the Amazon?
Promoting responsible tourism and alternative income sources (e.g., crafts, local products) reduces dependence on extractive industries and encourages forest conservation.
What role does international cooperation play in Amazon conservation?
Programs like the Amazon Fund, supported by countries like Norway and Germany, finance sustainable development and forest preservation. These efforts support Brazil in meeting climate goals.
