Case study - Amazon Rainforest

Question 1

Location of the Amazon

Answer 1

• Forms a belt around the equator and between the tropics
• Found in South America, Africa, SE Asia and Australia
• Amazon is located in south america and covers 9 countries including Brazil, Peru and Bolivia
• Worlds largest and biodiverse rainforest covers 5.5k”2
• Contains 300 billion trees, 15000 species and 200 million people

Question 2

Key facts about the Amazon?

Answer 2

• The worlds largest and biodiverse rainforest overing 5.5km”2
• Contains 300 billion trees, 15000 species and 200 million people
• Contains 1/3 of all carbon in the worlds biomass and emits 28% of the worlds oxegyn
• Fourth largest climate producer - 75% of GHG emissions from deforestation and land use change - 59% from slash and burn

Question 3

What is the climate of the Amazon?

Answer 3

• Annual rainfall 2000+mm in some places it can exceed **6000+mm **
• Some of the rainfall doesnt reach the ground but it is **intercepted by the forest and evaporated **
• Daily convectional rainfall
• Average temperature** 27 degrees **
• Plants form distincy layers, with some trees reaching heights of **45m **

Question 4

What is the Tropical Rainforest Water Cycle?

Answer 4

• The average discharge of water into the alantic by the Amazon is 175,000 m/s3 or 15% of all the worlds fresh water
• River amazon is the largest in the world by volume only 30% of all the amazons rainfall reaches the sea the rest is caught up in systems loop
• Very high rainfall exceeding 2000mm a year this is due to high humidity and unstable weather conditions
• Rainfall occurs on most days and often in the form of torrential downpour
• Dense canopy intercepts up to 75% of this rainfall - some drips to thr ground from leaves or flows down tree trunks as stem flow
• 25% of rainfall is evaporated, whilst remaining 75% half is used by plants and eventually returned to the atmosphere whilst the other half infiltrates into the soil, stored on ground surface or flowing as run off

Question 5

Tropical rainforest Carbon cycle?

Answer 5

• The warm wet climate is ideal for plant growth promoting the process of photosynthesis
• Absorbs huge quantities of co2 and in return the rainforest **emits 28% of worlds oxegyn **
• The Lungs of the Earth
• Stores between **80 and 120 billion tonnes of co2 **
• A **carbon sink storing 1-3gtc per year **
• Wood is **50% carbon - huge co2 store **
• Important carbon sink in mitigating the effects of climate change, respiration by plants trees and many animals in rainforests returning co2 to the atmosphere
• Decomposition is an active process in tropical climates - decomposes such as** bacteria, fungi thrive in warm wet conditions which release co2 back into the atmosphere **
• Some carbon may be s**tored within the soil or dissolved and then removed by streams as an output from the rainforest system **
• Bio-mass may be increasing 0.3%-0.5% a year due to rising co2 levels ( however rapid rise is too vast for tree growth ro offset climate change)
• Trees growing faster but dying faster

Question 6

Impact of human activity on the wc

Answer 6

• Half of the worlds rainforests have already been wiped out to make way for commercial farming ( plantations and ranching) mining, logging and settlements
• Deforestation appears to be slowing down but it is still a wide spread issue in countries such as indonesia

Question 7

Impact of deforestation on wc

Answer 7

• Atmosphere becomes less humid as** evapotranspiration is reduced **
• With **few trees **most **rainfall reaches the ground immediatley compacting soil and encouraging ground water flow **
• Exposed to sun **soil will become very dry and vulnerable to very little interception of rainfall or evaporation **
• Rates of runoff will increase -increased risk of flooding
• Rainforests allow for a considerable amount of **water to be returned to the atmosphere through evapotranspiration **
• When forests are replaced by pasture or crop evapotranspiration is reduced leading to **reduced atmospheric humidity and supressing precipitation **
• Deforestation could lead to 20% reduction in regional rainfall
• Changes in preciptation will lead to a reduction in river discharge
• Lead to flash flooding increasing silt washed into rivers and destroy fresh water eco systems and supplies which will impact the lives of indigenous people
• Warming weather will kill aquatic life due to changing biodiveristy
• Moisture evaporated from deforested areas forms shallow cumulous clouds which dont produce rain
• Loss of condensation nuclei - less could formartion - less rain

Question 8

Impact of human activity on the cc

Answer 8

• Amazon has lost **17% of forests in past 50 years **due (80% due to cattleranching)
• Most impact is in Brazil
• Common form of forest clearing is (**slash and burn **)burning which can easily burn out of control. Very cheap and effective but often too effective
• After a fire **forest shrub absorbs 40% less carbon **
• Burning releases co2 into the atmosphere
• Deforestation is one of the **main contributers to GHG emissions **
• The reduction in trees results in lowered photosynthesis until new plants colonise (most signifcant impact of deforestation)
• Plant and animal respiration drops to zero
• Rain washes **ash into soil increasing carbon content **
• Decompostion is non existent
• Replacing trees with crops and pasture **does not absorb as much co2 as trees **
• The** ability of amazon to absorb co2 is reducing each year from 2 billion tonnes in 1990s to 600 million tonnes in 2019 **
• Brazil is the **worlds 4th largest climate producer **
• forests absorb 11% more solar radiation than pasture
• Climate change is affecting **species diversity due to increased temperatures, droughts and wildfires **

Question 9

Local example of impacts of carbon cycle?

Answer 9

Bristol investment in public transport to reduce vehcile emissions of carbon demonstrates how the effects can be reveresed to some extent

Question 11

What is the average discharge of the Amazon into Atlantic

Answer 11

The average discharge of water into the alantic by the Amazon is 175,000 m/s3 or 15% of all the worlds fresh water

Question 12

What is the Amazons rainfall?

Answer 12

2000mm and can exceed 6000mm

Question 13

What is the temperature of the Amazon

Answer 13

27°

Question 14

How much of the world’s biomass of carbon is stored in the Amazon and emitted back into world as oxegyn?

Answer 14

Contains 1/3 of all carbon in the worlds biomass and emits 28% of the worlds oxegyn

Question 15

How much of the world’s biomass of carbon is stored in the Amazon and emitted back into world as oxegyn?

Answer 15

Contains 1/3 of all carbon in the worlds biomass and emits 28% of the worlds oxegyn

Question 16

Impacts of deforestation on evapotranspiration

Answer 16

• Atmosphere becomes less humid as** evapotranspiration is reduced **
• With **few trees **most **rainfall reaches the ground immediatley compacting soil and encouraging ground water flow **

Question 17

What is the size of the Amazon rainforest?

Answer 17

Worlds largest and biodiverse rainforest covers 5.5k”2
* Contains 300 billion trees, 15000 species and 200 million people
Covers 40% of South Americas land mass

Question 18

Reasons for deforestation?

Answer 18

• 80% cattle ranching as the eradication of foot and mouth diease in Brazil, devalution of the brazillian currency against the dollar
• Soya bean agriculture in brazillian states of Para, encouraged by a new variety of soya thriving in rainforest conditions
• Colonisation of growing populations in brazil
• Hydroelectric power generation - large hydroelectric damns hace veeb constructed on rivers such as Rio Tocantins and flooded large areas
• Oil and gas extratced in colombia, ecduador and peru, gold mining in brazillian state of para

Question 19

Why was the approval of the belo monte dam on xingu river controversial

Answer 19

• Controversial to enviromentalists and indigneious people
• Third largest dam in the world would flood 400km”2 and displace 12,000 locals

Question 20

What is logging

Answer 20

• Loggers take the best trees and clear/burn the rest land is then sown for cattle raising
• Illegal logging is a widespread problem
• Outright deforestation for timber is rare due to the dispersed nature of valueable wood such as kapok

Question 21

When did the rainforest experience a drought why was it an issue?

Answer 21

• 2005 and 2010 parts of the amazon basin experienced a drought
• 2010 event lowered the rio negro upstream from manaus isolating local people who depended on the river for transport
• Droughts can also promote natural wildfire

Question 22

Mitigating the impacts of deforestation?

Answer 22

• Establishing clear property rights over land - brazillian government is keen to establish a land registry to reduce land grabbing and illegal clearing
• REDD (reduced emmisions from deforestaion and forest degraders) - rich countries should pay poorer countries not to cut down trees 4.5 million was pledged to support the idea following coepnhagen climate talks 2009
• Encouraging market buyers to buy from legally registered sources - however destination for many tropical commodities is not eco sensitive
• Monitoring deforestation through sattelites and aeroplanes
• expanding designated areas to national parks and** indigeneous people
• Ecotourism** - protects rainforests from hunting logging, mining and provides local employment e.g The posada amazonas loge in peruvian amazon

Question 23

Problems with slash and burn

Answer 23

• Reduces the retention of humidity in the soils top layers down to a depth of one metre
• Facilitates sudden evaporation of water previously retained in the forest canopy
• Increases albedo and temperature
• Reduces porosity of soil causing faster rainfall drainage, erosion and silting of rivers and lakes

Question 25

Difference between pasture and forests

Answer 25

• Forests absorb 11% more solar radiation
• Soil temperature in ARF 20cm deep did not exceed 2.8 c and in pasture it was 8 c
• Moisture content of soil is 15% less in pasture than arf
• ARF deep roots pump 20-30% more air humidity and 5-20% mroe preciptation than pastures

Question 26

What is the temperature predicted to increase by?

Answer 26

• Temps increse 0.26 c every 10 years since mid 1970s
• By 2050 this will increase to 2-3 c

Question 27

Vegetation changes

Answer 27

• Massive net loss of forests in the amazon basin
• WWF states 20% of ARF has been lost and will rise to 27% if deforestation rates continue
• Also due to climate change - species only tolerate certain conditions
• Climate change alters the conditions - high temos and droughts killing of tree species
• 2 c rise above pre industrial levels will kill off 20-40% of the amazon within 100 years
• 3 c rise would kill off 75% of the amazon due to drought
• 4 c rise would kill 85%

Question 28

Soil changes

Answer 28

• Amazonian soils contain 4-9kg of carbon in upper 50cm of soil whilst pasture lands contains 1kg m/2
• During burning 30-60% of carbon is lost to atmosphere
• Unburned vegetation decays and is lost within 10 years
• Decomposers die off
• Soils exposed to heavy tropical rainfall when clearing occurs - washes away top soils attacking deep weathered layers below
• Most soil washed into rives

Question 29

River changes

Answer 29

• Overall reduction in river discharge
• Increase in silt washed into rivers which could disrupt river transport routes
• Flash flooding
• destroy freshwater ecosystems - remove source of protei and income to indingeious people
• destroy water supply - needs of amazoian people
• Kill of temperature dependent species
• change the biodiversity of the river system by introducing new species and killing off others
• reduce water dissolved oxygen concentrations which could destroy eggs and larvae which rely on dissolve oxygen for survival

Question 30

Mitigating the changes
(national and international agreements)

Answer 30

• The TARAPOTO process to help achieve harmomious forest development
• Amazon cooperation treaty organisation (ACTO) to promote harmonious development
• Latin american technical cooperarion network on watershed management