🌍 elss sg5 Flashcards
SG5!!! what is a positive feedback loop
self enhancing, accelerates original change
what is a negative feedback loop
self limiting, ultimately reverses original change
what is dynamic equilibrium
despite inputs and outputs of a system constantly changing in short term, in long term, a balance will be maintained
example of dynamic equilibrium in the water cycle
heavy rainfall = saturated ground, eventually water comes back up to surface through springs, rivers remove water so water table returned back to normal
example of dynamic equilibrium in the carbon cycle
fossil fuel combustion = higher atmospheric co2 = more photosynthesis = atmospheric co2 removed
how does urbanisation affect water cycle
- soil replaced by concrete (impermeable) so water can’t infiltrate
- more surface storage = more surface run off = higher flood risk
- drainage systems take water to rivers quickly = higher flood risk
how does urbanisation affect carbon cycle
- vegetation removed = less photosynthesis
- more co2 emissions from cars, homes, industry etc
how does farming affect water cycle
- irrigation systems mean lots of water lost by ET
- soil becomes very saturated = surface storage = surface run off = flood risk
- less interception by crops than trees
- ploughing creates channels for water = soil erosion
how does farming affect carbon cycle
- less biomass storage
- less soil storage as organic matter is exposed to oxidation
- soil is exposed so organic matter is removed by wind/rain
how does forestry affect water cycle
- more interception & interception loss
- less saturated soil = less run off = smaller flood risk
how does forestry affect carbon cycle
- more photosynthesis = more co2 storage in biomass
- more soil respiration = co2 released
- trees only becomes carbon sink 100 years after planting and by this time they may have been felled
what is the surface water extraction case study
the aral sea
aral sea location
in central asia in between kazakhstan and uzbekistan
when was the water extraction from the aral sea
1930s onwards
why was the water extracted from the aral sea
to develop irrigated cotton & rice farms in the area
what was the impact of the water extraction on the aral sea
water leaked or evaporated so less water to the sea.
by 2007, the sea was 10% of original size
what was the impact of water extraction from the aral sea on local climate
- less evaporation = less local rainfall
- seasons became more extreme as the sea kept the area cool in the summer as water was cool, and warm in the winter as the water warmed up over the summer
what is the groundwater extraction case study
london basin
what is water table
top of saturated zone
what is an unconfined aquifer
permeable rock that holds water that is not capped by impermeable rock
what is an aquitard
non porous rock which restricts flow of water from an aquifer
what is a confined aquifer
permeable rock that holds lots of water that is capped by impermeable rock
what is a recharge area
where a confined aquifer is unconfined
what is artesian pressure
creates a basin with a syncline
what is the london basin
artesian basin at the centre of a syncline where water is held in a band of chalk
why and when was water extracted
to power machinery during industrial revolution
what was the impact on the ground water store
water table fell by nearly 90m
describe the recovery of the water table
began to recover in 1990s, rising by 3m/per year
what was the impact on other flows and stores in the water cycle
- more infiltration & percolation bc soil was not as saturated (only unconfined areas)
- less surface stores due to more infiltration
what is combustion
when fossil fuels or organic matter is burnt and co2 is released
what is the biggest carbon emitter since 1750 and size
coal - 673 gt
where do most of the carbon emissions go
atmosphere - 879 gt
how does fossil fuel combustion impact ocean
- ocean takes in 30% of emissions
- as oceans warm due to global warming, less co2 diffuses into it, so more atmospheric co2
how does fossil fuel combustion impact biomass
- more atmospheric co2
- more photosynthesis
- plants grow more
- more photosynthesis
- less co2 in atmosphere
how has fossil fuel combustion impacted atmospheric temperatures
anthropegic change: fossil fuel combustion = warmer temps
what is the enhanced greenhouse effect
fossil fuel makes the ‘blanket’ around the earth thicker so less solar radiation can emit back into atmosphere so it is re emitted back to earth
what is carbon capture and storage (CCS)
where co2 released by combustion is captured from atmosphere and is transported and stored underground
what are the advantages of CCS
- would reduce emissions from power stations by 90%
- good potential in uk as surrounded by sea (can be stored under it)
- reduce co2 in atmosphere so reduce climate change
what are the disadvantages of CCS
- expensive
- may not be safe (could leak)
- better to spend money on renewable energy sources
diurnal changes to carbon cycle in amazon
day: sunny so more photosynthesis than respiration
night: more respiration than photosynthesis
diurnal changes to water cycle in amazon
day: sunny so lots of ET = condensation = precipitation
night: dark so less ET
diurnal changes to carbon cycle in arctic tundra
day: little vegetation & cold = little photosynthesis
night: even less
diurnal changes to water cycle in arctic tundra
day: cold = little ET
night: still cold = even less ET
seasonal changes to carbon cycle in amazon
summer & winter: same temps & same amount of sunlight all year round = same rates of photosynthesis = high NPP
seasonal changes to water cycle in amazon
summer: high precipitation & high temps = lots of ET & large stores
winter: slightly less precipitation but still a lot = still a lot of ET
seasonal changes to carbon cycle in arctic tundra
summer: long hours of sunlight & some vegetation = some photosynthesis
winter: dark = no photosynthesis
seasonal changes to water cycle in arctic tundra
summer: permafrost thaws so more surface stores = some ET
winter: water frozen
long term changes to carbon cycle
glacial period:
- carbon stored in bubbles in ice
- lower ocean temps so more co2 diffusing into it
- vegetation destroyed so less photosynthesis
= bigger atmospheric store
long term changes to water cycle
glacial period:
- most water stored in ice = low sea levels
- smaller biomass stores as vegetation destroyed
- less transpiration = lower temps = less ET
what is remote sensing
obtaining information from a distance
examples of remote sensing
- mapping forest fires
- weather predictions
- tracking city growth
advantages of remote sensing
- large areas
- see change over time
- see depth and height
- doesn’t disturb ppl or environment
disadvantages of remote sensing
- expensive
- requires specialists
what is geographic information systems (GIS)
a way of presenting remote sensing data
