Amazon Rainforest Case Study Water And Carbon Flashcards
(24 cards)
Describe the location of the Amazon Rainforest
Southern hemisphere - South America
Found in band between tropics of cancer and Capricorn
Majority lies in Brazil
Includes parts of 8 South American countries - covers 40% of the continent
20°N and S of equator lies in between tropics
Key facts - size
The Amazon rainforest is the largest on earth - 4% of earth’s surface and 2.1 million square miles of land
Key facts - climate
Hot (27°) and wet (2000+mm) - perfect conditions for plant growth
Key facts - biodiversity
Home to 20% species of plants and animals
1000 species of bird and 60,000 species of plants
What are the causes of deforestation in the Amazon?
Agriculture
Logging
Road building
Mineral extraction
Energy development
settlement and population growth
How does agriculture contribute to deforestation in the Amazon?
Agriculture to grow crops like Soya or Palm Oil or for pasture land for cattle grazing
How does logging contribute to deforestation in the Amazon?
Cutting down trees for sale as timber for building homes, furniture etc and pulp for making paper and paper products. Selective logging as wood highly valued is chosen.
How does road building contribute to deforestation in the Amazon?
Trees clear for roads, which are essential for Brazilian government to allow development of rainforest.
Making untouched forest more accessible and under threat from environment.
Trans Amazonian highway opened up large parts of forest and new road is going to be paved
How does mineral extraction contribute to deforestation in the Amazon?
Forests cleared to make way for huge mines.
Brazilian part of Amazon extract minerals such as iron, gold, nickel, copper, zinc
How does energy development contribute to deforestation in the Amazon?
Hydro-electric power use focus - 150 new damns planned for Amazon Rainforest alone.
Huge Belo monte started operating in April 2016 and generates over 11,000Mw of power
How does settlement and population growth contribute to deforestation in the Amazon?
Populations and settlements growing.
Many people migrating to forest to look for work.
Settlements have grown rapidly and replaced parts of forest
What are the impacts of deforestation on the water cycle?
Reduced evapotranspiration - cleared areas means air is less moist, resulting in reduction of cloud cover and less precipitation
Little trees so little interception compacting ground - rain reaches ground quicker. Increased rates of runoff and flood risk.
Exposed soil at risk of erosion, limits chances of regrowth.
Describe the canopy of the rainforest
Canopy - thickest layer 20-40m
Only around 1/3 of the rain that falls in the Amazon basin is discharged into the Atlantic Ocean.
Up to half interception of precipitation in canopy - Up to half of the rainfall in some areas may never reach the ground, being intercepted by the forest and re-evaporated into the atmosphere.
Regional impacts on water cycle
Rainfall levels likely to reduce as vegetation decreases with deforestation
Reduced evapotranspiration from cleared areas means air is less moist, resulting in reduction of cloud cover and less precipitation
Exposed soil at risk of erosion
Most rainfall reaches ground immediately + less interception increases runoff rates and flood risk
Future deforestation of Amazon could lead to 20% decline in regional rainfall
Local impacts on water cycle
Replacement of forests by pasture/crops - less evapotranspiration suppressing precipitation.
‘Vegetation breezes’ - air warms faster over cleared land creating local low pressure and moisture in air from forest areas, increase cloud cover, thunder, heavy rain over cleared land.
Burning forest areas produces airborne aerosols which vapour condenses on results in droplets too small to form rain clouds
Carbon cycle key facts
Rainforests store more carbon per unit area than in other ecosystems
Untouched forest takes more carbon than puts back in atmosphere - carbon SINK
Amazon forest covers estimated 5.3 million sq km and holds 17% of the global terrestrial vegetation carbon stock - shows that the Amazon forests help reduce global warming lowering the planet’s greenhouse gas levels.
A 2015 study confirms Amazon forests have acted as a long-term net biomass sink, but also found a long-term decreasing trend of carbon accumulation.
Rates of net increase in above-ground biomass declined by 1/3 during the past decade compared to the 1990s - means tropical forests are becoming less efficient at trapping carbon.
Wood is 50% carbon so rainforest are huge carbon stores
Human activity influences clearance for cattle ranching
Impact of deforestation on carbon cycle
30-60% carbon lost to atmosphere when forest is cleared
Photosynthesis ceases until new plants colonise area
Respiration drops
Water cycle key facts
Only around 1/3 of rain that falls into Amazon basin is discharged into Atlantic Ocean.
Up to 50% rain in some areas may never reach ground being intercepted by forest and reevaporated into atmosphere
50-80% remains in ecosystems water cycle in Amazon - used to form rain clouds and be cycled back into the ecosystem as precipitation
Feedback loops
Positive -
trees die due to drought and lack of water, carbon increase into atmosphere, warms atmospheric temp, increases drought
Vegetation breeze - air over cleared land warms faster, rises quick and creates localised low pressure drawing moist air from forest. Increase cloud cover, thunder, heavy rain
What is soy / cattle ban mitigation strategy
End deforestation
Linking soy bean industry to deforestation, global warming, water pollution
Won’t buy soy beans/beef from deforested areas
businesses only buying products from certified areas
Protection mitigation strategy
Over half of Amazon protected - indigenous land
Norway mitigation strategy
Pledged $1billion for brazils Amazon fund
Only paid when they can prove they have reduced deforestation
How does deforestation contribute to climate change
Tropical forests are very important carbon sinks, but deforestation and degradation is turning
sinks into carbon SOURCES.
The degradation (reduction in quality of tropical forests) and deforestation releases the carbon stored within the trees back into the atmosphere.
Forests that experienced disturbances eg) logging and fires store 40% less carbon than undisturbed
forests.
This makes climate change alone a major impact of tropical forest destruction with respects to the carbon cycle.
How has the political leader affected deforestation?
More recently, deforestation started to rise again due to new political leader Jair Bolsonaro – he has the view the Amazon is there to be used for profit. 2018-19 rates increased, but still well below the peak.
A new president Lulu has has since been re-elected and seeks to reverse deforestation
