Case Study: Rainforest Flashcards
Location of the Amazon Rainforest
South America
670 million hectares
What is the climate ?
Hot, wet with dense vegetation
Describe how the water cycle affects the Amazon?
lots of evaporation over Atlantic Ocean, wet air blown towards Amazon leading to a very high rainfall; high temperature causes lots of evaporation, leads to high precipitation; dense canopy so large amounts of interception, leads to slower runoff into rivers; populated by species adapted to high humidity and frequent rainfall
Describe how the carbon cycle affects the Amazon?
lots of carbon stored in vegetation and soil, making it a carbon sink; carbon dioxide in the atmosphere increases productivity in the amazon, this increases the amounts of photosynthesis which increases biomass; therefore increasing carbon sequestration; however trees have been dyeing younger so it may not continue to be an effective carbon sink
What is the effect of deforestation in the water cycle in the Amazon?
less interception, increased soil erosions and soil saturation, increased runoff meaning increased risk of flooding; decreased rates of Eva port aspiration, less clouds, less rainfall and so increased risk of drought
What is the effect of deforestation to the carbon cycle in the Amazon?
less roots to hold soil together, heavy rain washes nutrients (carbon) out of topsoil and into the hydro sere; less leaf litter, less humus, less new growth so less carbon stored in vegetation; less trees, therefore less carbon dioxide sequestration, enhance of greenhouse effect and global warming.
What is the effect of climate change on the Amazon Rainforest?
increase in temperatures and decrease in rainfall leads to droughts; droughts can lead to extinctions and forest fires which release carbon dioxide into the atmosphere, this leads to a loss of carbon by decomposition and a decrease in photosynthesis, meaning less carbon dioxide sequestration
What are some human methods of managing deforestation in the Amazon?
selective logging
Few trees from each area will maintain forest structure, soil isn’t exposed, allows regeneration, only small impact on water and carbon
replanting
Important types of trees that were removed are replanted, ensures variety for future and local carbon and water cycles return to initial state (Peru plans to restore 3.2m hectares of forest by 2020)
environmental law
Ban use of wood from forests not managed sustainably, ban excessive logging, control land use (Brazilian Forest Code says landowners have to keep 50-80% of land as forest)
protection
Set up national parks (Central Amazon conservation Complex in Brazil (established in 2003) protects biodiversity in an area of 49000 km-squared while allowing logical people to use the forest sustainably); with these areas, damaging activities such as logging can be monitored and prevented.
Outline how changes to the water and carbon cycle impacts the tropical rainforest?
Changes in precipitation may lead to flash flooding, destroyed freshwater ecosystems and a reduction in river discharge, which can kill temperature reliant species
Increase in atmosphere co2 can lead to a growth in trees. However they live faster and die younger. Therefore there will be an increase in trees dying.
Increase in atmospheric co2, increases advanced greenhouse effect. A 3 c temp increase would lead to 75% of the forest being destroyed by drought. Therefore there would be an increased risk of wildfires and increases decomposition, will lead to a further increase of co2 in the atmosphere.
Deforestation reduces the carbon absorbed from the atmosphere by photosynthesis and reduces the carbons store (biosphere). Also exposes soils to heavy rainfall, which weathers soil, transferring carbon into the water store (lithosphere). Soil can also become thin and lack nutrients.
Outline feedback between the water and carbon cycles in tropical rainforests?
- Increased atmospheric carbon increases global air temps. Therefore can result in a mass death of tropical rainforest due to increased droughts in tropics. Therefore there is increased decomposition of biomass and increased release of c02. (Positive feedback mechanism)
- Increased atmospheric carbon increases global air temps. Which increases evaporation. Therefore there is increased cloud coverage an deflection of solar radiation back into space. Which can decrease global air temps. (Negative feedback mechanism )
- Deforestation is reducing evapotranspiration, which can result in the atmosphere becoming less humid. This can reduce rainfall and increase risk of droughts for trees. If there are fewer trees, there is less infiltration and evaporation of leaves. Further reducing evapotranspiration. (Positive feedback mechanism)
Rank order the extent of human impacts on the water cycle using water and carbon cycles? Using rainforest case study)
- Deforestation (largest)
- 80,000km^2 lest yr - Mining (but local scale)
- causes 10% deforestation. However in concentrated areas.
- worlds largest iron ore mine - Agricultural practices (varies)
- 80% deforestation for cattle - Climate change (global, however uncertain of extent)
- IPCC predicts dry seasons to become 3 weeks longer
What has been done to save the Brazilian rainforest?
- cut finance for deforestation (made illlegal)
- created protected areas
- monitoring showing where deforestation is happening in real time
- making whole supply chain responsible for handling goods produced by illegal logging.
What are the successes of the strategies employed?
- decreased deforestation by 75% in 10 years
- avoiding the emissions of 3 billion tonnes of co2
- managed to grow the economy at the same time as reducing deforestation
What concerns still exist?
- still largest deforestation rate in the world
- need to limit warming to 2 c
What are ideas to rescue the effects in the future
Leap frog dirty technologies - allow developing nations to reach clean energy not via fossil fuels (cheaper)
Stop investing in carbon producing industries
Gain transparency on exactly how much and who is emitting emissions
Sharing the responsibility between governments, businesses and civil society
