EQ3 Flashcards
1
Q
6.7a
malthusian crisis model
A
- went up geometircally/expenetial-1,2,4,8,16,32
- arithmetic growth- 1,2,3,4,
- but wouldnt reach x (where resources crosses pop) as theres checks in place to keep population down-wars, epidemics
- boserup: GM crops to keep resources up, inovation to stop problem
2
Q
forests
A
- Forest covers 30% of the Earth’s land area, although only 15% are ‘natural’ primary forests – found in Canada, Alaska, Russia and the north-western Amazon basin
- role in carbon cycle: carbon sink, sequestriation n carbon capture, carbons asborbed by photosynthesis-30.4, releases 24.5 total carbon emissions by respiration, 64 stored in below ground biomass
3
Q
deforestation
A
- clearance of forests for timber n land
- land=provide grazing for livestock n produce cash crops
- loss of over 500k ha in brazil n indonesia
4
Q
afforestation
A
- helping offset loss of tropical rainforest ‘services’
- but much is taking place on what was agricultural land
- net gain of 500k in china 1990-2015
5
Q
deforestation in madagscar
causes
A
- since 1950s its rainforest has been cleared at rapid rate
- 1950 there was 11.6 mill hectares of rf land, 1985=3.8mill
- due to pressures from gov to grow cash crop
- 80% now gone
- roads=significant destruction force in rf as they open it up to large machinery
- demand rose due to growing interntaional demand for tropical hardwood, expanding pop debt repayments
6
Q
madagascar deforestation
impacts
A
- as rf dissappears the co2 emissions increase
- it has a major impact on size of terrestrial carbon store
- removing forest has a colossal impact on both fluxes n stores
7
Q
impacts of deforestation on water cycle
A
- infiltration=decreased
- runoff n erosion^
- flood peaks r higher n lag time=shorter
- ^ discharge leads to flooding
- ^ eroded material is carried in river- as bed load and silt n clay in suspension
- annual rainfall=reduced n seasonality of rainfall=^
8
Q
impacts of deforestation on soil health
A
- raindrop impact washes fine particles of clay n humus away
- coarser n heavy sands r left behind
- co2=released from decaying woody materials
- biomass is lost due to reduced plant growth/photosyenthesis
- rapid soil erosion leads to loss of nutrients
- ^ leaching (loss of nutrients from soil by infiltration) means minerals=lost
9
Q
Impacts of deforestation on atmosphere
A
- turbulance=^ as heated ground induces convectional air currents
- oxygen content is reduced n transpiration rates=lower
- less shading leads to ^ direct sunlight reaching forest floor
- reduced evapotranspiration makes it less humid
- air=dryer
- evapotranspiration rates from resultant grasslands r about 1/3 of tropical rf
10
Q
Impacts of deforestation
on biosphere
A
- evaporation from veg is less
- less absorption of co2 means decreased carbon store
- species diversity= decreased (eg less resisident forest plants die off)
- ecosystem services r decreased
- decrease in habitants means fewer animal species survive
- biomass is lost, bc of less plant growth/photosynethesis
11
Q
reorestation
A
- an establishment of a forest cover in a colation where the forests have been cleared in recent past, usuallly to repurpose the land for activities like agriculture or mining
- cons: decreade biodoversity, ^ soil erosion n loss of water resources if done improperly
- pros: slows flooding impacts-dispers water
12
Q
Grassland conversion
A
- temperate n tropical grasslands have become heavily exploited by agriculture
- both have suffered as result of over exploitation
- simple act of ploughing leads to an immdeiate loss of both co2 n moisture, as well as change in runoff characterstics
- theres 3 main types of grassland conversion that cover approximately 26% of global land area.
13
Q
savannah grass land
A
- eg sahel africa
- wetland
- tropical
- 2 seaons wet n dry
- wild fires
- baobab trees w thick curvy bark that resists fires
- bumoda grass
- humans use it for food n wood production
14
Q
piraries
A
- eg n america
- flat, fertile lands dominated by grasses.
- hold soil firmly in place=minimal erosion
- grass roots=good at reaching water more than a meter deep n can live v long
- low rain n thin soils
- strong winds
- 80 species of animals n 300 of birds
- wind n soil erosion remove grass=dust storms
15
Q
steppe grasslands
A
- eg eurasian steppe, us great plains
- dry w temperate climate
- drastic seasonal changes
- cold winters n hot summers w little rainfall during year
16
Q
benefits of natural grasslands
A
- trap moisture n food water
- absorbs toxins from soil
- provide cover for dry soils
- maintain natural habitats
- act as carbon sink- absorb co2 n release o2 all year round=lung effect
- act as terrestial carbon store
17
Q
disadvantages of converting grasslands to grow biofuel crops
A
- initial removal releases co2
- annual ploughing enables soil bac to release co2
- they need carbon based nitrogen fertiliser n chemical pesticides so produce net ^ of co2 emisions
- theyre heavy consumers of water=need irrigation which has big impact on aquifers
- cultivated soils r liable to erosion by runoff n wind
- natural habitats r reduced
- the lung effect is reduced
18
Q
urbanisation
A
- biggest land use conversion
- big demand for space needed to accomadate rising urban pop n widening of economic activities
- biggest disrputive impact on carbon n water cycles
- towns n cities=focal points of both GHG emissions n intense water demand
19
Q
6.7b
oceans role in carbon cycle
A
- carbon sequestration: biological carbon pump-fragile system, phytoplankton takes up C, if change in temp n acidicty it might change
- absorbs 30% of co2 produced by human activities since 1800
- carbon carbonic
- carbon sink
- sedimentation- animal/plant shells fall of n sink n form rocks- dead remains of skeletons lead to limestone
20
Q
ocean acidification
A
- decrease in alkalinity/ph of oceans
- cause by uptake of co2
- occurs bc oceans n carbon sinks
21
Q
carbon sinks
A
absorbs more carbon from the atmosphere than it releases
22
Q
changes in ocean acidification
A
- in 19th century=8.2 now 8.1(2015)
- seem small but theres been large change in ph of surface waters
- 2100 projected: ^ concentration of atmospheric co2, fewer n smaller marine calcilifiers, fewer carbonate ions, 7.8,
- vulnerable organisms: clams, plankton, finfish, lobsters
- coral reefs - they stop growing once ph less than 7.8
23
Q
critical threshold
A
- point which damage is irreversible
24
Q
ecosystem resilience
A
- leevl of distrubance that ecosystems can cope w/while keeping og state
25
Q
6.7c
how worlds forests as carbon stores=challeneged
A
- deforestation
- poleward shift of climate belts
- increasing drought
26
Q
el nino n la nina
A
- as well as rising temps scientists have blamed a spike in el nino effect for dramtic impacts experienced in recent years
- conditions:
- trade winds=weaker allowing warm surface water along equator to pile up along coast of s.usa then move cali n chile
- rain clouds form over this warm part of ocean
- clouds move inland n dump ^ rain on usa
- meanwhile indonesia n australia suffer droughts
27
Q
case study
amazon drought
A
- drought of 2014-2015
- rivers dried n fish died
- drier forests gets less carbon it can store
- forest absorbs about 1.5bn tonnes of Co2
- in 2005 drought it released 5bn tonnes of c
- 2010-released 8bn tonnes
- when trees die it shifts balance n not a sink anymore
- it pumps 20bn tonnes of water into atmosphere daily
- its uniform humidity lowers atmospheric pressure allowing mositure from atlantic to reach across continent
- droughts mean its sequestering less co2 from atmosphere= ^ GHG effect
- drought= plays a dimished role in hydrological cycle
28
Q
6.8a
ecosystem services assesment
A
- ecosystem services: supporting
- provisioing, cultural, regulating - constituents of well being
- security, basic material for good life, health, social relations
- freedoms of choices n action
29
Q
forest lost impacts on wellbeing
A
- the un has described worlds forests as ‘fundamental’ to human well being n survival
- over 1.6bn ppl depend on forests n over 90% of these=poorest in society
- forests, like other ecosystems r essential due to services they provide as well as being source of around 80% of global biodiversity
30
Q
forests r important for:
A
- sequestering carbon dioxide from the atmosphere
- storing carbon
- transferring moisture from the soil back into the atmosphere by evapotranspiration
31
Q
kuznets curve
A
- as they reach higher leevls of development n wealth socities reach a tipping point when costs of resource exploitation become fully realised n =set against benefits of resource conservation n protection
1. uk pre industrial revolution, remote amazonia, indonesia pre 1970s- low income, low enviromental degradtion
2. indonesia today, china 20th century- ^ in income, large ^ in enviromental degradation, rising income worsens enviromental impacts
3. china today- shallower gradient, almost at peak enviromental degradtion, middle level income
4. uk today- (post industrial service economy) rising income reduces enviromental impact
32
Q
case study
indonesia
palm oil plantations
A
- palm oil fruit used in many food products (cheapest veg oil on market)
- borneo rainforest=souirce of 1/2 worlds PO
- its protected under indonesian law n un enviromental programme=identified as orangutangs natural habitat (last of asia)
- £5bn a year frim food n biofuel
- protected forest=being logged eg by dutu palma group
- estimate 88% all timber logged there=illegal
- area double size of wales=earmarked for future dev
- 40% orangutangs habitat=destroyed last 2 decades- 50,000 died in recent years- pop reduced by 50%
- deforestation causes wildfires
33
Q
case study deforestation
coca plantations, peru
A
- ^ threat to indigenous ppl n their hunting grounds, due to reduction to area n biodiversity
- 90% used for cocaine production of red zone east peru=cause deforestation
- peru, bolivis n columbia=worlds major producers of coca
34
Q
6.8b
rising temps resulting from GHG emissions r ^ both evaporation rates n amount of water vapour.
This in turn, is impacting on:
A
- precipitation patterns- ^ 0.8mm daily over ocean, reduce in brazil RF, more droughts in some places more intense rain in others,
- river regimes-
- drainage basin stores
- the cryosphere
35
Q
ice loss and arctic albedo
A
- earths cryosphere has been affected by GW
- over last 20yrs the antarctic n greenland ice sheets had negative mass balance n in N hemisphere spring snow cover=continued to decrease in extent n thickness
- melting of permafrost
- carbon uptake by terrestrial plants=^ bc lengthening growing season
- loss of albedo as ice once covered land surface=now tundra n then taiga
- sunlight previsouly reflected of ice now absorbed=^GW
- sea ice regulates evaporation n rain
36
Q
climatic barometer
A
- measure atmospheric pressure
- arctic=early warning system for rest of planet, acting as a barometer for climate health of the planet
37
Q
increase temp has implications on
rain patterns
eg of yukon
A
- lead to ^ evaporation n atmospheric water vapour
- across yukon, winter rain ^ between 1950 n 1998
- but greater proportion fell as spring rain n less as snow than before
- climate scientists agree annual precipitation will ^ by 5% n 20% by 2100
38
Q
increase temp has implications on
river regimes
eg of yukon
A
- snowmelt now begins earlier in yukon n snow cover=decreasing
- alters RR bringing earlier peak flows to most river basins
- between 1958 n 2008-total ice area shrank by 22% n as glaciers recede streamflow=decreasing-despite initial ^ in meltwater
