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Clevedon School Geography 1.1 - Water and Carbon Cycles (Whole Unit)
Terms in this set (181)
what is an input?
an input is something put into the system from the outside e.g. precipitation into the lake
what is an output
an output is something leaving the system to the outside e.g. runoff moving underground from the system
what is energy?
energy is power or driving force e.g. energy is lost to surroundings after a chemical reaction
what are stores/components?
stores/components are individual elements or parts of a system e.g. trees, soil
what are flows/transfers?
flows/transfers are the links or relationships between the components e.g. infiltration, evaporation
what is positive feedback?
positive feedback is a sequence of events which carries on in a loop that increases change in a system which promotes environmental instability (e.g. trapped greenhouse gases in trees are released from system, enhancing greenhouse effect, meaning temperatures increase and permafrost melts)
what is negative feedback?
negative feedback is a sequence of events which carries on in a loop that neutralizes the effects of change in a system, promoting stability (e.g. increased CO2 in atmosphere means higher temperatures so more plants can grow as photosynthesis is happening at a faster rate. this means there are more plants to take in CO2 from atmosphere)
what is dynamic equilibrium?
dynamic equilibrium is a state of balance within a constantly changing system e.g. woodlands where there has not been much human or natural impact so conditions remain mostly the same
what is the atmosphere?
the atmosphere is a thin layer of gases surrounding Earth
what is the lithosphere?
the lithosphere is the solid, outer layer of the earth that consists of the crust and the rigid upper part of the mantle
what is the hydrosphere?
the hydrosphere is all the water on the earth's surface in liquid form
what is the biosphere?
the biosphere consists of all life on Earth and all parts of the Earth in which life exists
what is the crysosphere?
the cryosphere is all the water held in the form of ice, as glaciers or ice caps, etc.
what are boundaries?
boundaries are the point at which energy and matter is transferred between systems i.e. the edge of the system
what is an isolated system?
an isolated system that can exchange neither energy nor matter with its surroundings.
what is a closed system?
a closed system is one in which no matter is allowed to enter or leave, but that can still transfer energy around a closed loop
what is an open system?
an open system is one in which exchanges of matter or energy occur across system boundaries
what are the major stores of water on the earth?
the hydrosphere, lithosphere, cryosphere and atmosphere are all store water
where is most water stored?
most water on the earth is stored in the hydrosphere (96.5%), as most is in the oceans or other freshwater on the surface such as lakes
which store has the lowest amount of water?
the atmosphere only has 0.001% of water stored on earth as water vapour
which processes drive change in the magnitude of water stores over time and space?
Different flows occur to change the magnitude of each water store:
> cloud formation and precipitation
> cryospheric processes
what is evaporation?
evaporation is when liquid water changes state into a gas, becoming water vapour
how does evaporation change the amount of water in each store?
after evaporation, more water is stored in the atmosphere
how does the amount of evaporation vary?
magnitude of evaporation flows varies by location and season: lots of solar radiation and water means more evaporation
what is condensation?
condensation is when water vapour changes state to become a liquid
how does condensation change the amount of water in each store?
water droplets formed from condensation can flow to subsystems on earth, meaning there is less stored in the atmosphere
how does the amount of condensation vary?
magnitude of condensation flow depends on the amount of water vapour in the atmosphere and the temperature. rapid temperature drop and lots of water vapour means more condensation
how are clouds formed?
rising warm air holds water vapour, which cools and condenses into small droplets as it rises, which gather together to form clouds
why does precipitation happen?
when droplets get big enough as so much water vapour has condensed, they fall as precipitation
how does cloud formation and precipitation vary?
precipitation can vary seasonally and by location (i.e. more rain in tropical areas)
what are cryospheric processes?
cryospheric processes affect the total mass of ice at any scale from local patches of frozen ground to global ice amounts
what are examples of cryospheric processes?
accumulation (the addition of snow or ice to a glacier) and ablation (the natural removal of snow or ice from a glacier) are cryospheric processes
how does the amount of different cryospheric processes vary?
when the global temperature is colder, more water freezes so more is transferred to ice and less is transferred away by melting. high temperatures have reverse effect.
over what timescale can variations in cryospheric processes happen?
some changes in global temperature took place over thousands of years (e.g. after last glacial period) while some occur over short timescales (e.g. more snow falls in winter than summer)
what is a drainage basin?
a drainage basin is an area of land drained by a river and its tributaries
what type of system is a drainage basin?
a drainage basin is an open system
what are the inputs to a drainage basin system?
the only input for the drainage basin is precipitation (the movement of water from the atmosphere to the ground surface)
what are the different water stores in a drainage basin?
- soil water
what does interception storage mean?
interception storage is water held on vegetation (e.g. lands on their leaves) for a short period of time after precipitation has fallen.
what is surface storage?
surface storage is water stored on impermeable surfaces, creating puddles and ponds
what is soil water storage?
soil water storage is water stored in the soil moisture
what is groundwater storage?
groundwater storage is water stored in soil or in rocks (e.g. aquifers)
what is channel storage?
channel storage is water held in a river or stream channel
what are examples of flows and transfers in a drainage basin?
- overland flow
- channel flow
what is infiltration?
infiltration is water soaking into the soil
what is overland flow?
overland flow (runoff) is water flowing over the land which happens as rain is falling on the ground faster than infiltration can occur
what is stemflow?
stemflow is water running down a plant stem or tree trunk
what is channel flow?
channel flow is water flowing in the river or stream (river's discharge)
what does saturated mean?
saturated means all the pores in the soil or rock are full of water
what is the water table?
the water table is the level below which the ground is saturated with water.
what is throughflow?
throughflow is water moving slowly downhill through the soil
what is groundwater flow?
groundwater flow is water flowing slowly below the water table through permeable rock
what is percolation?
percolation is water seeping down through soil into the water table
what are the outputs from a drainage basin?
evapotranspiration and runoff are outputs from a drainage basin system
what is evapotranspiration?
evapotranspiration is the process by which water is transferred from the land to the atmosphere by evaporation from the soil and other surfaces and by transpiration from plants.
what is PET?
Potential evapotranspiration is the amount of water that could be lost by evapotranspiration based on temperature of the environment but it does not take into account amount of water
what is the water balance in a drainage basin?
the water balance shows the equilibrium between inputs to the drainage basin and outputs. the water balance impacts how much water is in the drainage basin
how does the general water balance in the UK change?
the water balance in the uk shows seasonal patterns:
> in wet seasons, there is more precipitation than evapotranspiration so river discharge increases
> in drier seasons, precipitation is lower than evapotranspiration so there is not much water in the ground stores as water used by plants is not replaced. this creates a deficit of water
> ground stores recharge in next wet season
what is river discharge?
river discharge is the volume of water that flows in a river per second (m^3/s, cumecs)
what are flood hydrographs?
flood hydrographs are graphs of river discharge around the time of a storm event
what is peak discharge?
peak discharge is the highest point on the graph, where river discharge is highest
what is lag time?
lag time is the delay between peak rainfall and peak discharge as the rainwater flows into the river
what is the rising limb?
the rising limb is the increase in river discharge as rainwater flows into the river
what is falling limb?
the falling limb is the decrease in river discharge as the river returns to its normal level as less water is flowing into it
what is base flow?
base flow is the regular flow of a river before the storm
parts of a flood hydrograph diagram
how does the size of a drainage basin impact runoff?
larger drainage basins catch more precipitation so have a higher peak discharge as more total runoff. smaller drainage basins have shorter lag time as water has shorter distance to travel so runoff reaches river faster.
how does the shape of a drainage basin impact runoff?
wide, circular drainage basins have steeper rising limb and higher peak discharge as all points on watershed (boundary of drainage basin) are same distance from river so lots of water reaches river at the same time
how does relief impact runoff?
runoff flows faster downhill so lag time decreases and peak discharge increases as water does not have time to infiltrate soil so runoff increases.
how does rock and soil type impact runoff?
impermeable rocks and soils mean there is less infiltration so there is more runoff so peak discharge increases.
which natural variations cause change in the water cycle?
storm events and seasonal changes cause change in the water cycle
how do intense storms impact the water cycle?
intense storms generate more precipitation and greater peak discharge in hydrographs. this means flows and stores increase in magnitude, while some flows may not be able to occur rapidly enough to cope with size of input, (e.g. infiltration) increasing runoff
how do seasonal changes impact the water cycle?
during winter, low temperatures cause water to freeze so flows to drainage basins decrease in magnitude and more water is stored as ice. when ice melts, flows are larger. in autumn, when trees lose their leaves, interception is less so runoff to river channel is higher, along with other stores
which human activities cause change in the water cycle?
farming practices, land use change and water abstraction cause change in the water cycle
how do farming practices impact the water cycle?
> ploughing increases infiltration as surface is broken up, decreasing runoff
> more crops means more interception so less runoff and more evapotranspiration so more precipitation
> lifestock can compact the soil, increasing runoff and decreasing infiltration
> irrigation causes more runoff and extraction of water means less groundwater stored
how do land use changes impact the water cycle?
> deforestation reduces interception, increasing runoff.
> removal of dead plant material on the soil means less water is held by these materials in the ground, meaning there is less infiltration
> more roads means more impermeable surfaces, increasing runoff and decreasing infiltration
how does water abstraction impact the water cycle?
water extracted from stores to meet demand (particularly in dry seasons) means less is stored in lakes and rivers
what are the major stores of carbon?
carbon is stored in the lithosphere, hydrosphere, cryosphere
biosphere and atmosphere
what is the order of size for carbon stores from largest to smallest?
1) lithosphere (over 99.9%)
5) atmosphere (0.001%)
how is carbon stored in the lithosphere?
over 99.9% carbon is stored in sedimentary rocks like limestone and a small proportion of carbon is stored in fossil fuels
how is carbon stored in the biosphere?
carbon is stored in the tissues of living organisms and is transferred to the soil when they die and decay
how is carbon stored in the cryosphere?
carbon is stored in soils as permafrost where decomposing plants and animals have frozen in the ground
how is carbon stored in the atmosphere?
carbon is stored in the atmosphere as methane or carbon dioxide
how is carbon stored in the hydrosphere?
CO2 is dissolved in oceans, lakes and rivers. some is found at the surface and exchanged with the atmosphere but most is found deep in the ocean
which flows and transfers drive change in the magnitude of carbon stores over time and space?
• carbon sequestration
what is photosynthesis?
photosynthesis is the process by which plants and phytoplankton use energy from the sun to produce glucose and oxygen to help the plant grow
how does photosynthesis change magnitude of stores of carbon?
photosynthesis means carbon dioxide is taken in from the atmosphere to plants, so store in atmosphere decreases and store in biosphere increases
what is respiration?
respiration is the process by which organisms break down glucose for energy
how does respiration change magnitude of stores of carbon?
respiration means carbon is transferred from living organisms to the atmosphere as carbon dioxide, meaning biosphere store decreases and atmosphere store increases
what is decomposition?
decomposition is the process by which decomposers break down dead biomass
how does decomposition change the magnitude of stores of carbon?
decomposition means carbon is transferred from the biosphere to the atmosphere as carbon dioxide and methane and to the soil (lithosphere) as humus
what is combustion?
combustion is the burning of a substance to release energy
how does combustion change the magnitude of stores of carbon?
combustion causes carbon to be transferred from biosphere (biomass) or lithosphere (fossil fuels) to atmosphere as carbon dioxide
what is carbon sequestration?
carbon sequestration is a natural or artificial process by which carbon dioxide is removed from the atmosphere and held in solid or liquid form (e.g. in fossil fuels or sedimentary rocks) for millions of years
how does carbon sequestration change the magnitude of stores of carbon?
carbon sequestration means less carbon is stored in the atmosphere and more is stored in the lithosphere
what is weathering?
Weathering is the breaking down of rock over a long period of time.
how does chemical weathering happen?
carbon reacts with water vapour to form acid rain, which dissolves some rocks when it falls on it. the soluble molecules from this reaction are washed into the sea via rivers, where they react with CO2 to form calcium carbonate. this is used by sea creatures to make shells
how does weathering change the magnitude of stores of carbon?
chemical weathering transfers carbon from the atmosphere to the biosphere and hydrosphere
what are fast carbon flows?
fast carbon flows take only a few days to transfer carbon between sources (e.g. photosynthesis, respiration, combustion, decomposition)
what are slow carbon flows?
slow carbon flows take many years to transfer carbon between sources (e.g. sequestration, weathering)
which flows happen at a plant scale?
at plant scale, respiration and photosynthesis are the main flows
which carbon flows happen at sere scale?
at sere scale, combustion and decomposition occur as well as those taking place at plant scale
which flows happen at continental scale?
at continental scale, all flows including sequestration occur
which natural variations cause change in the carbon cycle?
wild fires and volcanic activity cause changes in the carbon cycle
how do wild fires cause change in the carbon cycle?
- wildfires rapidly transfer large quantities of carbon from biomass (biosphere) to the atmosphere due to combustion
- loss of vegetation leads to less photosynthesis so less carbon is removed from the atmosphere
- in the long term, fires encourage growth of new plants, meaning more photosynthesis, so fires can be neutral in terms of effect on amount of atmospheric carbon
how does volcanic activity cause change in the carbon cycle?
- carbon stored in magma is released during volcanic eruptions as CO2 to the atmosphere
- if eruption is large enough, there can be extreme disruptions to the carbon cycle
which human activities cause change in the carbon cycle?
• hydrocarbon fuel extraction and burning
• farming practices
• land use changes
how does hydrocarbon extraction and use impact the carbon cycle?
extracting and burning fossil fuels releases CO2 into the atmosphere, meaning carbon which would have remained in the lithosphere is emitted to the atmosphere
how do farming practices impact the carbon cycle?
> animals release CO2 when they respire and digest food
> ploughing releases CO2 which was stored in the soil
> growing rice in rice paddies releases methane
> machinery used for farming causes CO2 emissions
how does deforestation impact the carbon cycle?
when forests are cleared, carbon that was taken in by trees from the atmosphere is released back to the atmosphere
how does land use change impact the carbon cycle?
• clearence of vegetation to make space for buildings means less CO2 is stored in the biosphere and more is released to the atmosphere
• concrete production releases CO2, so expansion of urban areas causes more release of CO2
what is the carbon budget?
the carbon budget is the difference between the inputs of carbon into a subsystem and outputs of carbon from it
what is a carbon sink?
a carbon sink absorbs more carbon than it releases (i.e. inputs outweigh outputs)
what is a carbon source?
a carbon source releases more carbon than it absorbs (i.e. outputs outweigh inputs)
why is the carbon cycle important for land?
the carbon cycle allows plants on the land to grow:
- without carbon plants would not be able to photosynthesise
- without decomposition nutrients of dead plants would never be recycled so new plants would never grow
what impact would change in the carbon cycle have upon land?
changes in the carbon cycle can cause less carbon to be stored on land. e.g. increase in temperature caused by global warming means permafrost melts so CO2 is released to the atmosphere and there are more wildfires
how does the carbon cycle impact the atmosphere?
the carbon cycle means greenhouse gases containing carbon are released to the atmosphere, contributing to the greenhouse effect, which keeps the earth at a suitable temperature to support life
what impact would change in the carbon cycle have upon the atmosphere?
more greenhouse gases released to the atmosphere due to human activity, so more heat is trapped by the atmosphere
what impact does change in the carbon cycle have on the climate?
more greenhouse gases emitted to the atmosphere means the greenhouse effect is enhanced, so more infrared radiation emitted by the earth's surface as it converts UV light to heat is absorbed and re-emitted by the atmosphere back to earth. this means temperatures rise (global warming), causing climate change
how does the carbon cycle impact the oceans?
as part of the carbon cycle, carbon dioxide is dissolved directly into the oceans from the atmosphere, where it is used by organisms like phytoplankton during photosynthesis and other marine organisms to form calcium carbonate shells and skeletons
what impact would change in the carbon cycle have upon the oceans?
- increased CO2 levels means oceans become more acidic as more CO2 is absorbed by oceans, so some marine life can't survive.
- global warming means ocean temperature increases, so phytoplankton may not be able to survive meaning less photosynthesis happens so less carbon taken in from atmosphere
- warmer water absorbs less CO2 so more stays in atmosphere
how does carbon support life on earth?
carbon is a fundamental building block of life as many cells in organisms are made from carbon
how does water support life on earth?
water is essential for life as all living things need to take in water to survive
what is the relationship between the water cycle and carbon cycle in the atmosphere?
water is present in the atmosphere as water vapour and carbon exists as carbon dioxide as well as methane. these contribute to the greenhouse effect, which keeps the earth at temperatures high enough to support life
what is an example of positive feedback in the water cycle?
1. temperature rises
2. evaporation of water increases
3. more water vapour in atmosphere
4. enhanced greenhouse effect
5. temperature rises
what is an example of negative feedback in the water cycle?
1. temperature rises
2. evaporation increases
3. more clouds
4. more sunlight reflected back to space
5. temperature falls
what is an example of positive feedback in the carbon cycle?
1. more CO2 in atmosphere
2. enhanced greenhouse effect
3. temperature rises
4. respiration rate increases
5. more CO2 in atmosphere
what is an example of negative feedback in the carbon cycle?
1. more CO2 in atmosphere
2. photosynthesis rate increases
3. more CO2 absorbed and stored by plants
4. less CO2 in atmosphere
how do the carbon and water cycles interact with eachother?
• carbon reacts with water in the atmosphere, creating acid rain and chemical weathering, which removes carbon from atmosphere
• water is needed for photosynthesis, which removes carbon from atmosphere
• amount of CO2 in atmosphere affects global temperatures, impacting amount of evaporation that can happen, which affects precipitation and further rise in temperatures
what implications will climate change have on the weather?
> precipitation pattern will change as wetter areas will get wetter and drier areas will get drier, increasing water shortages and conflict
> extreme weather events are more frequent, which particularly affects developing countries as they cannot deal with impact
> sea levels rise, increasing risk of flooding in coastal and low lying areas
what implications will climate change have on food?
if the climate changes, agricultural productivity will decrease in some areas, which could lead to food shortages
what implications will climate change have on animal species?
geographical range of some species will change as a result of climate change (i.e. different species will inhabit different areas). arrival of new species may damage an ecosystem or cause other species to become extinct due to competition
`what implications will climate change have on marine life?
if temperatures increase, plankton population size will decrease, which will impact other food chains
what is the IPCC?
the Intergovernmental Panel on Climate Change (IPCC) is an international organisation set up by the UN to share knowledge about climate change.
how can humans mitigate the impacts of climate change?
in order to prevent large scale temperature increases, humans must reduce the transfers of carbon to the atmosphere
how can humans intervene in the carbon cycle in order to mitigate the impacts of climate change on an individual scale?
individuals can choose to use their cars less or buy more fuel efficient cars. they can also make their homes more energy efficient (e.g. with insulation or double glazing)
how can humans intervene in the carbon cycle in order to mitigate the impacts of climate change on a regional and national scale?
• governments can reduce reliance on fossil fuels for heating and powering homes by increasing availability and reducing cost of renewable energy sources
• afforestation increases carbon uptake by biosphere
• planners can create more green spaces or improve public transport
• governments can invest in carbon capture and storage so CO2 emitted from fossil fuels is captured and stored underground
how can humans intervene in the carbon cycle in order to mitigate the impacts of climate change on a global scale?
> countries can work together to agree treaties such as the Paris Agreement 2015 which control amount of greenhouse gases released
> carbon trading schemes give limits ro countries and businesses on emissions they can produce - if they produce less they can sell extra credits, if they produce more they must buy more credits
how did land use change around salmon's brook after 1777?
after an act in 1777, most of the woodland known as enfield chase was deforested. some has since been replanted but still only a small portion of it remains
how did the land use change around salmon's brook after 1777 impact flood risk?
a reduction in vegetation meant less rainwater was intercepted, increasing overland flow and so increasing channel storage. also, less trees meant less water was absorbed from underground, increasing water that flows to river as groundwater flow. this increased flooding
how did land use around salmon's brook change after 1880?
between 1880 and 1920, Edmonton was urbanised, creating terraced housing near the river for workers who worked in industry nearby
how did change in land use around salmon's brook after 1880 impact flooding?
urbanisation meant that there were more impermeable surfaces such as concrete near the drainage basin, increasing overland flow and decreasing infiltration, meaning water flowed into the river faster. urbanisation also lead to the clearing of vegetation, decreasing interception storage.
how did land use change around salmon's brook after 1920?
between 1920 and 1940, winchmore hill and oakwood park were suburbanised,
how did change in land use around salmon's brook after 1920 impact flooding?
suburbanisation meant there were more detached houses, meaning an increase in impermeable surfaces and overland flow, increasing flood risk. however, this did not increase flood risk as drastically, as detached houses have gardens, which allow infiltration and interception to take place.
how did land use change around salmon's brook after 1947?
in 1947, the green belt act led to the protection parks as well as golf courses
how did change in land use around salmon's brook after 1947 impact flooding?
more parks meant there was more interception and infiltration, which decreased flood risk as there was less overland flow. however, golf courses are designed to stay dry so have efficient drainage systems which meant water that landed on golf courses flowed quickly to the river
how did land use change around salmon's brook after 2000?
in 2000, a field was replaced by highlands school
how did change in land use around salmon's brook after 2000 impact flooding?
the construction of Highlands School meant there were more impermeable surfaces, meaning an increase in overland flow and flood risk. also, the field allowed infiltration and interception to take place, but this did not happen as much when the school was built, increasing flood risk.
what are example of salmons brook flooding?
in october 2000, salmons brook overflowed its banks.
in march 1947, there was large flooding around the drainage basin
what human factors caused salmons brook to flood in october 2000?
- before 2000 many home upgrades had taken place, such as patios, paving and extensions, increasing impermeable surfaces.
- the construction of highlands school (more overland flow) and golf courses (have pipes underground to allow quick throughflow) also increased flood risk.
what natural reasons caused salmons brook to flood in october 2000? (4)
1) in autumn, there are not many leaves on trees, meaning there is less interception storage.
2) some leaves and debris may have fallen into the river, blocking the flow of water away from salmons brook, causing flooding.
3) upper section of the river is steep, meaning infiltration does not happen, increasing rate of overland flow
4) river got twice as much autumn rain (400-600mm, average for whole year is 550mm) as it was used to, including a storm on 30th october
what were the impacts of the flood at salmons brook in october 2000?
as a result of flooding at salmons brook:
> around 200 homes were flooded (montagu road worst affected)
> over 100 were rescued from homes
> areas of open space in arnos park, lee valley, etc flooded
> £200 million property damage
> cemetry near Edmonton Green was flooded
what flood defences were built in montagu road (edmonton) as a result of flooding in 2000?
as part of plans for the salmons brook flood alleviation scheme, a new embankment around montagu road recreation ground was built. this contained flood water so that it did not reach nearby properties, and instead flooded the park. slopes of the embankments were covered in grass, meaning it had a natural appearence
what flood defences were built at salmons walk (edmonton) as a result of flooding in 2000?
at salmons walk, new flood walls of up to 1 metre high were built on both banks of the walk. the banks would be reshaped to make them sloped, increasing volume of the channel, decreasing flooding
what flood defences were built at grange park as a result of flooding in 2000?
at grange park, a flume was built in the channel, which meant that during regular days, water flows through the channel, but if rainwater causes discharge to get too high, gate shuts, preventing as much water from flowing downstream to high value properties and allotments in edmonton, instead flooding the golf course, creating a temporary lake. clay embankments either side of flume increase volume of channel
what natural caused salmons brook flood in march 1947?
- there was cold snow for two months throughout the winter of 1946/47, which did not melt due to freezing temperatures
- on 12-14th march, storms blew in from atlantic, bringing warmer air and 80mm extra rain, causing snow to melt
- ground was frozen so all water flowed to river as overland flow due to impermeable surface
- there was no interception of precipitation as no leaves on trees or crops in the ground
what human factors caused salmons brook to flood in march 1947?
- between 1920 and 1940, winchmore hill and oakwood park were suburbanised, creating more impermeable surfaces and overland flow
- flood defences were not maintained due to economic damage due to world war II
what is an example of a tropical rainforest?
the amazon is a tropical rainforest in south america
how does the water cycle affect the amazon rainforest?
> lots of evaporation over the atlantic ocean, so wet air is blown to amazon, meaning lots of rainfall
> warm temperatures in amazon means evaporation high in rainforest, meaning more precipitation
> dense canopy means interception is high so less water in rivers
how does the carbon cycle affect the amazon rainforest?
• lots of carbon stored in vegetation and soil (so carbon sink)
• lots of co2 in the atmosphere means lots of productivity in vegetation (more photosynthesis) so biomass increasing so more co2 now sequestered in the amazon
• trees are also dying younger due to more co2 in atmosphere, so less co2 sequestered in amazon
how is deforestation in the amazon impacting the water cycle?
• in deforested areas, there is no tree canopy to intercept rainfall, so more water reaches ground, increasing overland flow and flood risk
• deforestation means less evapotranspiration, meaning less clouds form and rainfall is reduced, increasing droughts
how is deforestation in the amazon impacting the carbon cycle?
> without roots binding soil together, rain washes away nutrient-rich top layer, so carbon stored in soil is transferred to hydrosphere
> less trees means less leaf litter is on the ground, meaning humus does not form by decomposition. this means there is not enough nutrients in the soil to support growth, so less carbon stored in trees
> trees remove co2 from atmosphere and store it, so deforestation means there are less trees to absorb co2 from atmosphere, enhancing the greenhouse effect and global warming
how is climate change impacting the amazon rainforest? (6)
> temperature increase is causing increase in drought - severe droughts happened in 2005 and 2010
> plants and animals living in forest are adapted to moist conditions, so species die due to dry weather - some may become extinct (e.g. endangered black caiman reptile)
> more drought means more forest fires, which destroys large areas of forest, releasing co2 to atmosphere
> 4 degree increase in temperature could lead to 85% of the amazon being killed, meaning lots of decomposition and less trees to absorb co2 from atmosphere
> all glaciers below 6000m height in the andes in peru will melt, increasing flood risk
what are some examples of attempts to limit human impacts on the amazon? (5)
1) selective logging
4) protected areas maintained with PFP
5) international agreements
what is selective logging?
selective logging is when only some trees are felled (e.g. older ones)
what are the advantages of selective logging?
+ if only a few trees are taken from each area of the forest, structure of forest is kept, meaning canopy remains so soil is not exposed
+ forest can still regenerate so carbon cycle not impacted as much
what are the disadvantages of selective logging?
- some trees are still lost by selective logging, so biodiversity is reduced
what is ecotourism?
ecotourism is tourism that uses the natural environment of the forest
what are the advantages of ecotourism?
+ ecotourism creates many new jobs for local people
+ it creates $7 billion for the brazillian economy per year
+ encourages the conservation of the rainforest rather than its destruction
what are the disadvantages of ecotourism?
- ecotourism takes animals out of their natural habitat against their will, which may be seen as cruel
- some trees need to be deforested to make room for hotels and other sites for tourists
what is reforestation?
reforestation is when new trees are planted to replace the ones that are cut down
what are the advantages of reforestation?
+ if all trees cut down are planted back, there will be no net loss in amount of co2 stored in the forest (e.g. Peru plans to restotre 3.2 million hectaires of forest by 2020)
+ younger trees absorb more co2 rapidly so if these are continually planted, more co2 will be absorbed by the forest
what are the disadvantages of reforestation?
- if different types of trees are planted in place of the ones cut down, biodiversity may be damaged as some animals lose their habitats
what are protected areas?
protected areas are regions of the forest where it is illegal to cut down trees or use the land for other purposes
what are the advantages of protected areas?
+ prevent loss of habitat for some animals, protecting biodiversity
+ reduces emissions of co2 to atmosphere
what are the disadvantages of protected areas?
- often, governments cannot afford to maintain protected areas (e.g. to hire enough staff to monitor them or technology to track those who engage in illegal logging)
what is PFP?
Project Finance for Permanence is the funding of a project by public (e.g. german government and Global Environment Facility) and private donors such as corporations
what are the advantages of PFP?
+ detailed financial plans are agreed by all donors, so that scheme is successful in the long term
+ funds are held back until the total fundraising goal is reached, encouraging donations as donors know their money will be put to good use
+ companies can build better working relationships with government officials with whom they need to work
+ $215 million fund was agreed in brazil, covering the cost of 60 million hectares of land (1.5 times size of canada)
how can international agreements prevent human impact on the amazon?
brazil could have an agreement with countries who they are in debt to , which states that the country will cancel the debt if Brazil conserve the rainforest
what are the advantages of international agreements designed to prevent deforestation?
+ international agreements give the brazillian government an incentive to create stricter environmental laws to protect the forest, as they know this would give them more money than deforestation
what are the disadvantages of international agreements designed to prevent deforestation?
- the country who brazil are in debt to may be reluctant to lose money in favour of conserving the rainforest
- once debt is canceled, deforestation may continue so not a long term solution
- difficult to quantify how much rainforest should be conserved in an agreement, so deforestation may still happen
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