The Carbon Cycle Flashcards
Flux
The rate of movement of carbon between stores
Organic
Carbon found in living organisms
Store
A location where carbon is held (sometimes called a carbon sink)
Anthropogenic
Impacts of human activity on the carbon cycle
Systems
How the carbon cycle operates with inputs, outputs, stores, and flows
Equilibrium
A balance between different fluxes
Petagrams/Gigatonnes
Units used to measure carbon (1 billion tonnes)
Reservoir Turnover
Time taken for a store to refresh its carbon (output old, and input new)
What is the carbon cycle?
A biogeochemical cycle whereby carbon is stored and moved between the atmosphere, land and the oceans through flows or fluxes
Is the carbon cycle an open or closed system?
Closed
What are the two main components of the carbon cycle?
- biological
- geological
Which of the two components of the carbon cycle is shorter and which is longer?
- biological= shorter
- geological= longer
How is oil formed?
- remains of dead aquatic plants and animals die and sink to the sea bed
- lack of oxygen causes anaerobic decomposition
- compression and heating occurs
- oil and gas occurs in pockets under caprocks
How is coal formed?
- remains of trees, ferns and other plants are covered in layers of silt/mud
- lack of oxygen causes anaerobic decomposition
- compression and heating occurs
- the higher the compression and heating, the harder the coal
Mechanical weathering
The breakup of rocks by frost shattering and exfoliation produces small easy-to-transport particles
Chemical weathering
breakdown of rocks by carbonic acid in rain, which dissolves carbonate-based rocks
Biological weathering
burrowing animals and the roots of plants can break rocks up
Transportation
rivers carry particles (ions) to the ocean, where they are deposited
Sedimentation
over millennia these sediments accumulate, burying older sediments below, such as shale and limestone
Metamorphosis
the layering and burial of sediment causes pressure to build, which eventually becomes so great that deeper sediments are changed into rock
positive feedback mechanism example
more volcanoes = more CO2 in atmosphere (increases temp) = more C acid = more chemical weathering = more transportation of bicarbonate ions to oceans = more sedimentation and burial of CaCo3 = more metamorphism (so more metaphorphises of rocks) = more rocks melting
the movement of c between stores in the geological c cycle (EXPLAINED)
processes:
chemical weathering - CO2 in atmosphere reacts with some minerals to form calcium carbonate (limestone)
(or)
biological weathering - plant and animal particles break down after death
Then….
Transportation - this calcium is then dissolved by rainwater/ or small rock pieces (ions) are carried to the oceans. These form with bicarbonate ions to become calcite
Sedimentation - once there, it can precipitate out of the ocean water, forming layers of sediment on the sea floor. These will accumulate for millennia, burying the older sediments below (eg. shale and limestone)
Metamorphises - the layering and buryal of these sediments causes pressure to build and the limestone becomes marble and the shale becomes slate OR form oil deposits
Then….
through tectonic uplift, these sediments are either subducted underneath the continents, or the uplift will expose previously buried limestone
Finally….
The CO2 is then re-emitted into the atmosphere through volcanic erruptions (volcanic outgassing - eg Iceland 2010 volcano)
the movement of c between stores in the geological c cycle (SUMMARY)
chemical or biological weathering
transportation
sedimentation
metamorphises
tectonic uplifting
CO2 re-emitted through outgassing
biological c cycle (fast cycle)…. what is it?
fast movement of c between the atmosphere, ocean and ecosystems
large exchange fluxes between stores and rapid turnover (between a few years to a milennia)
c is sequestrated in and flows between land, atmosphere and oceans
the background of ocean sequestration…
(The three pumps)
in the ocean, c can be moved in three ways…
1 - biological pump: sequestration of c by phytoplankton
2 - carbonate pump: inorganic c storage w/ shells
3 - physical pump: absorption of c by water
the thermohaline circulation (THC)
the global system of surface and deep water ocean currents is driven by temperature and salinity differences between areas of the ocean
thermo = temp
haline = salinity (how salty it is)
cold saline water sinks, warm rises as it expands and becomes less dense and releases CO2 into the tropical warm environments
oceanic sequestration: how surface ocean CO2 is moved to the deep ocean - biological pump
microorganisms involved: phytoplankton
where in ocean? near surface (to access sunlight for photosynthesis)
name for rapid growth rates for phytoplankton = net primary productivity (NPP)
location where NPP is greatest - shallow waters of continental shelves, arctic and southern oceans (= v. productive areas)
how is c transported back to ocean surface waters? passed up in the food chain to fish and zooplankton which releases CO2 back to water and the atmosphere
amount of c phytoplankton sequesters annually to the deep ocean = 2M metric tonnes
oceanic sequestration: how surface ocean CO2 is moved to the deep ocean - carbonate pump
types of sea creatures: plankton, coral, oysters, lobsters
what are their shells made of? CaCO3 (calcium carbonate)
how is c transferred to thee deep ocean? the organisms die and sink, reaching the sea floor sediments
oceanic sequestration: how surface ocean CO2 is moved to the deep ocean - physical pump
CO2 is mixed more slowly in the oceans than the atmosphere and therefore there is greater spatial variation in CO2 concentrations
cold waters:
downwelling = cold water = denser = water sinks = currents bring dissolved CO2 to the deep ocean = CO2 moves into slow moving deep ocean currents and stays there for centuries
warm water:
eventually, the deep ocean currents return to the surface in a process called upwelling (mainly occur along coastlines). this brings deep, cold water to the surface causing the water to warm and some of the dissolved CO2 is released into the atmosphere
ocean currents (like the north atlantic drift):
downwelling and upwelling currents are important components of the deep ocean conveyor belt and are important in physically transporting c compounds to drift parts of oceans
define sequestration
removal of c from atmosphere into ocean or land by physical or biological processes
define terrestrial
the land (ie. ecosystems)
define organic carbon
c stored in living things (eg. phytoplankton)
define inorganic carbon
c stored in non living things (eg. rocks)
terrestrial sequestration mainly happens in which 5 ecosystems?
- tropical rainforests (TRF)
- wetlands
- peatbogs
- tundra
- mangroves
explain the process of terrestrial sequestration…
- primary producers (eg. plants) take c out’ve the atmosphere through photosynthesis and release CO2 back into the air via respiration
- primary and secondary consumers eat the plants, c from the plants becomes part of their fats and protiens
- micro-organisms (ie. bacteria and funghi)and detritus feeders (ie. beetles) feed on the waste from animals and the c from this becomes part of them
- after animal and plant death, tissues such as leaves decompose faster than wood
- decomposition is fastest in tropical climates (high rainfall, temperature and oxygen levels)
- however, decomposition is very slow in cold, dry conditions or where there is shortage of oxygen
- in arctic biomes, ecosystems are locked down by the extreme cold for long periods of time
on a large scale, photosynthesis is…..
photosyntheis is at its peak in the summer and CO2 drops (more sunlight = more photo)
photosynthesis is at its lowest in the winter and CO2 increases
on a small scale, photosynthesis is…
photosynthesis is at its peak during the day, and CO2 drops
photosynthesis is at its lowest during the night (respiration increases), and CO2 increases (no sunlight, so cant photo)
factors that determine the capacity of soil to hold c
soil type:
clay soils have higher c storage content than sandy soils as the clay protects c from decomposition
agriculture :
since 1850, soils globally have lost 40-90 Bil tonnes of c through cultivation and disturbance (soil is less of a sink and more of a source)
climate:
higher temps = higher rates of decompopsition so less c storage
higher rainfall = increases c storage
CASE STUDY: the amazon rainforest
5.3Mil km2
17% of global c is sequestered
brazil nut trees are v. important in this process
there’re 16,000 species of trees
1% of tree species store 50% of the forests’ c
factsors that have reduced the forests ability to sequester c: dead trees release their stored c back into the atmosphere
annual c emissions from dead trees = 1.9 Bil tonnes
annual c sequestration = 2.2 Bil tonnes
soil facts
20-30% of global c = stored in soils
2 ways c is stored in the soil:
1. organic c
2. inorganic c
how is c released back into the atmosphere?
decomposition
how does the depth of soil affect c cycling?
deeper soils store more c
61% of c is stored stored deeper than 30m
mangroves…
- sequester 1.5 metric tonnes of c per hectare annually
- little c can be respired back to atmosphere as there is no oxygen
- when drained, c is released back into atmosphere
tundra…
- contains c as long as its frozen
- much of the soil is permanently frozen containing ancient c
tropical rainforests (TRF)…
- HUGE c sinks (rain and humidity) (most in vegetation, not soil) but v. fragile, little (leaf) litter and dead wood decays
- they’re recycled so quickly so store doesnt devel., absorb more CO2 than any other terrestrial biome (30% of NPP)
atmospheric c and the greenhouse effect (GHE)
CO2 causes temp as its a greenhouse gas (gg). so if CO2 increases, so does temp
regular pattern - due to milankovitch cycles
increase in sea lvls due to to ice melt (peaks in interglacial)
what is the natural GHE?
a warming process that occurs when gg are absorbed and re-radiate infra-red radiation from the earth’s surface, trapping heat in the atmosphere, leading to a temperature increase
what is the enhanced GHE?
the natural GHE is enhanced by human activity (eg. burning fossil fuels), leading to an excessive amount of gg which increases global temp, meaning more heat is absorbed and trapped
4 examples of greenhouse gasses (gg) are…
CO2
Methane
Water Vapour
Nitrogen
define the radiative forcing effect
the difference between insolation (sunlight) absorbed by the earth and energy radiated back to space
define positive radiative forcing
the earth recieves more incoming energy from sunlight than it radiates to space. the net gain of energy causes warming
order of concentration of gg
water vapour (highest)
carbon dioxide
methane
nitrous oxide (lowest)
what is water vapour?
most abundant gg
acts as feedback to climate
increases earths atmosphere warms
what is CO2?
minor but important component of the atmosphere
released through natural processes (eg. respiration) and human activities (eg. deforistation)
humans have increased atmospheric CO2 concentration by more than a third since the industrial revolution
what is methane?
hydrocarbon gas
produced both naturally and through humans
what is nitrous oxide?
powerful gg pruduced by soil cultivation
explain the distribution of rainfall and temperature
due to the tilt of the earth, the sun concentrates most of its rays at the equator and theres a higher pop. along equator (not in poles) so theres lots of CO2 there
this means that the ground is heated up more which leads to more evaporation
as a result, more clouds form which leads to more precipitation along the equator than in the poles
eg. in central africa and northern south america which have the highest temps
this is because they’re low latitude and so recieve the most direct solar radiation, increasing their average temp
avg. rainfall is low in particularly continental areas
what are biomes?
they are different ecosystems
temps and water availability drives what ecosystems we have
if biomes change, soils change too
factors that affect precipitation, temp and biome distribution
proximity to water bodies
types of surface - albedo
global atmospheric circulation (GAC)
(whats the fourth?? its in our book in a table but i didnt write the name of t6he last one :) )
factors that affect precipitation, temp and biome distribution: proximity to water bodies
how it affects precip:
increases water evap and moisture
more humidity
how it affects temp:
water has high heat capacity, affecting temp as distributes heat
how it affects biome distribution:
has some influence on biome distribution
factors that affect precipitation, temp and biome distribution: types of surface
how it affects precip:
indirectly
how it affects temp:
mainly affects the temp
high temp = high albedo
how it affects biome distribution:
it doesnt
factors that affect precipitation, temp and biome distribution: global atmospheric circulation (GAC)
how it affects precip:
high pressure zones have low precip, low pressure zones have low precip
GAC affects the high and low pressure zones
how it affects temp:
cells impact temp - cells maintain temp along the bands of latitudes
how it affects biome distribution:
hot regions = desert
polar = tundra
factors that affect precipitation, temp and biome distribution: altitude
- relieff rainfall- rains on one side due to the pressure of moving over the mountain
- the higher you go the cooler it gets due to the decrease in infra-red radiation
- it affects biomes because the higher latitudes create specific biomes
What are some ways that the abstraction of fossil fuels can affect climate?
- Arctic ice shelves will melt adding more freshwater to the southern ocean, chaninging density and convection
- aberage Arctic temp has already increased at twice the global average over the last 200 years
- precipitation will increae in higher latitudes and decrease in lower latitudes
What are some ways that the abstraction of fossil fuels can affect ecosystems?
- 10% of land species will face extinction as the climate gets warmer, wetter or drier
*plants changes will lag behind animal changes as they can’t move; they will fact pests & deseases - 80% of coral reefs could be bleached
What are some ways that the abstraction of fossil fuels can affect the hydrological cycle?
- rivers will dry up in regions where precipitation is reduced or less effective because of higher evaporation rates
- small glaciers will disappear, decreasing river discharges once they have gone
- extreme heavy precipitation events will become common, with precipitation increases over the northern hemisphere land areas
What is the structure of the atmosphere?
top- thermosphere
mesosphere
stratosphere
troposphere
bottom- ground
What are the signs that a soil is healthy?
- dark, crumbly and porus
- contains many worms and other organisms
- provides air, water, and nutrients for micro-organisms and plants to thrive
- comtains more carbon or organic matter
- improves resilience to wetter weather
- retain moisture
What happened in the Pleistocene era that slowed down the carbon cycle?
the northern hemisphere summers cooled because of the Milankovitch cycles which triggered the last ice age which slowed the carbon cycle
What is an example of where coral bleeching happened due to the combustion of fossil fuels?
Great Barrier Reaf
What are two example of how the combustion of fossil fuels affected the hydrological cycle?
- flooding in Vietnam
- drought in Germany
What are some examples of how the climate was affected by the combustion of fossil fuels?
- Arctic warming twice as fast (Arctic amplification)
- destructive wildfires in California
Domestic energy
energy sources (avaliable) within a country
Foreign energy
energy that must be imported from abroad
renewable energy
energy from a source that is not depleted when used
non-renewable energy
comes from sources that will run out or will not be replenished in our lifetimes
Primary energy
an energy source that can be used without haveing to alter it
Examples of primary energy
- coal
- gas
- solar
- hydroelectric
Secondary energy
an energy source that has been adapted for human use
Examples of secondary energy
- electricity
- hydrogen
- biofuels
Energy mix
the combination of different energy sources used to meet a country’s total energy demand
Long term energy security
investing to balance economic development with environmental needs
Short term energy security
being able to react quickly to supply/demand changes
Human factors that determine a country’s energy consumption
- public perception
- standard of living
- technology
- economic development
- environmental priorities
- cost of energy
Physical factors that determine a country’s energy consuption
- physical avaliability
- climate
- cost of energy
TNCs roles in energy pathways
exploring, extracting, trandporting and refining petrochemical
OPEC roles in energy pathways
own 2/3 of the world’s oil and therefore are very important suppliers of energy
Energy companies roles in energy pathways
they convert primary energy sources into electricity and distribute it to the consumer
Consumers role in energy pathways
demand and use the energy. Examples include transport, industry and somestic users
Governments roles in energy pathways
they are gardians of national energy security (therfore demand it for their people) and they can supply/source energy (many TNCs are state funded)
Do TNCs and OPEC share a strong agreement, some agreement, some disagreement, or stong disagreement?
strong agreement
Do TNCs and governments share a strong agreement, some agreement, some disagreement, or stong disagreement?
some disagreement
Do TNCs and consumers share a strong agreement, some agreement, some disagreement, or stong disagreement?
strong disagreement
Do OPEC and governments share a strong agreement, some agreement, some disagreement, or stong disagreement?
some agreement
Do OPEC and consumers share a strong agreement, some agreement, some disagreement, or stong disagreement?
strong disagreement
Do consumers and governments share a strong agreement, some agreement, some disagreement, or stong disagreement?
some agreement and some disagreement
What situations might exist that could change the conflicts between TNCs, OPEC, governments, and consumers?
- corruption in governments
- international agreements that focus on environments
- wars/conflicts
- distrubutions on pathways
How is oil transported?
- pipelines - lower carbon footprint
- ships - slow and only an option for transport across water
- truck - flexible, highest carbon footprint
- rail - expensive, higher carbon footprint
How is coal transported?
- trucks - 1 billion tonnes moved each year
- railroad - 70% of coal used in USA is transported this way
- ships - less expensive, for long distances
How is gas transported?
- pipelines - main way, wuick, highly pressurised
- ships - gas has to be liquified
Who are the three largest producers of coal?
- China
- India
- USA
What two countries are the largest exporters of coal?
- Indonesia - 401 tonnes
- Australia - 198 tonnes
Who is the number one global producer of oil?
Middle East - 10.8EJ
Where does the one energy pathway from Russia for oil go?
Europe
How is the Russian gas delivered to Europe compared to the Middle East’s gas to Europe?
Russia - pipelines
Middle East - sea
What are the factors that cause energy insecurity and disrupt energy pathways and give examples?
- accidents - Suez Canal block
- fossil fuel acceleration
- increase in price - Russia-Europe gas
- war and conflict - Boko Haram in Nigeria
- terrorism/piracy - USA - Russia proxy war in Syrian conflict
- natural hazards - Hurricane Katrina (8 million gallons of oil spilled)
Recyclable energy
one that can be used over and over but must first go through a process to prepare it for re-use. The process can be human-driven or naturally occuring
Solar power:
What are solar water heaters?
they use the suns energy to heat water and then store it in a tank for later use
Solar power:
What are photovoltaic cells?
they convert light energy to electrical energy via semiconducting materials
Solar power:
How can you concentrate solar power?
use reflective materials (mirrors and lenses) to concentrate sunlight into a central point
this is used in large scale commerial solar
What percentage of the world’s energy is produced through wind power?
1%
What ercentage of the world’s electicity does nuclear power account for?
15%
Environmental costs of renewable energy
- some countries don’t have the physical geography for renewable energies
- more valleys will be drowned for HEP to be used and offshore zone used for wind farms and solar farms
Environmental benefits of renewable energy
- it’s a clean source of energy, meaning, it has low or zero carbon and greenhoouse emissions. It reduces the effects of global warming, climate change, and degredation of air quality and acid rains
Social costs of renewable energy
- HEP and tidal power are the only two that can provide base-load electricity (the amount to meet the minimum demand on a grid)
- nimbys - people reject the idea of remewables when it is close to where they live
- manufacturing and transportation of solar pannels currently requires the use of fossil fuels and is expensive
Social benefits of renewable energy
- mitigate the likelihood of diseases related to fossil fuel use like heart disease, cancer, and neurological disorders
Economic costs of renewable energy
- oil price declined in 2015, so renewable is more expensive and therefore less attractive
- there are still challenges to generation of large quantities of power in renewable energy technology compared to traditional forms of energy generation like fossil fuels
- setting up renewable energy generation facilities requires a huge financial outlay
Economic benefits of renewable energy
- they do no deplete over a lifetime so are more reliable and lead to enery security
- once infrastructure for the harnessing of the renewable resources is laid down, there is a zero to low maintenance required. This means that the owners of the facilities will reap big profits while providing cheap electricity
CASE STUDY: The UK’s changing energy mix:
Main energy source in 1970
oil
CASE STUDY: The UK’s changing energy mix:
Main energy source in 2015
oil and natural gas
CASE STUDY: The UK’s changing energy mix:
% of UK’s primary energy given by oil and natural gas
80%
CASE STUDY: The UK’s changing energy mix:
Has our energy consumption increased or decreased since 1970?
decreased
CASE STUDY: The UK’s changing energy mix:
How have we managed to achieve a decrease in our energy consumption?
- people are more environmentally aware
- more efficient production and use of energy
- shift from secondary to tertiary
- rise of a less energy intensive service sector at the expense of industry
CASE STUDY: The UK’s changing energy mix:
% of energy reduction in households
12% less
CASE STUDY: The UK’s changing energy mix:
% of energy reduction in industry
60% less
Economic costs of solar energy
- some solar farms take up productive farmland, which people argue should be producing food at a time when food costs are rising
- initial prices to set up is high
Economic benefits of solar energy
- economic benefits for small businesses/individual households wit reduced bills
Environmental costs of solar energy
- electricity may be needed to pump water in photothermal systems or to roatate heliostats
Environmental benefits of solar energy
- very little environmental impact during use. usually no habitat loss, as panels usually placed on buildings
Economic costs of wind energy
- the technology is expensive. high stike price - £155-120/MwH
Economic benefits of wind energy
- draws investment into UK from energy TNCs. contributes to the UK’s energy security
Social costs of wind energy
- some local residents see them as a blot on the landscape
Social benefits of wind energy
- creates construction jobs
Environmental costs of wind energy
- the rotating blades can hit birds and kill them
- visual and noise pollution
Environmental benefits of wind energy
- provides clean, renewable source of electricity that does not emit harmful greenhouse gases
Environmental costs of nuclear energy
- potential problems if not managed
- if nuclear waste is leaked it can cause contamination and environmental damage
Economic costs of nuclear energy
- costs a lot to maintain nuclear waste disposal sites. there is a high strike price- £92.50/MwH
Economic benefits of nuclear energy
- jobs are created working in nuclear power station, and at nuclear waste disposal sites
- nuclear ower produces much more energy per unit weight of fuel than other alternatives
Social costs of nuclear energy
- risk of contamination / dangers associated with working in nuclear power plants
Social benefits of nuclear energy
- if nuclear waste is contained in sealed containers with adequate absorbing materials or space so the radiation released does not affect the workers or public, then waste storage is safe
TABLE WE DIDN’T COMPLETE BUT I THUNK EMILY DID
Pedge from UK gov. for 2040
to have completely electric cars. renewable energy sources are at the centre of this plan so theyre going to become increasingly impotant
CASE STUDY: Alternative to FF: Hinkley point
£18B project
provide energy for 60yrs
25,000 jobs through French owned EDF and China General Nuclear
will provide 7% of the UK’s energy mix
CASE STUDY: Renewable energy: Christchurch, Bournemouth
£50M, size of 175 football pitches
UKs largest solar farm
will serve 60,000 houses in Bournemouth
define biofuels
fuels produced from organic matter
can be classed as either:
1. primary biofuels - organic materials that are used in an unprocessed form eg. fuelwood
2. secondary biofuels - from the processes of biomass eg. liquid biofuels such as ethanol and biodeisel
there has been an _______ in the demand for biofuels
increase
CASE STUDY: biofuels in Brazil
started to diversify energy in 1970s to increase energy security
they use sugar cane ethanol which is made from sugar and etnanol
+) Brazil are now supposedly carbon neutral
+) significant reduction in co2 emissions
+) Brazil = #1 producer of sugar cane and leading exporter of ethanol
-) large scale clearing of TRF
-) use pesticides and fertilizers so can keep up w/ demand = killing non target species = eutrophication
-) area used to grow sugar canebas more than doubled since 2003 = leading to the displacement of other agriculture= deforistation
-) deforistation isncancelling out the effect of decreased co2 emissions
are biofuels c neutral?
there are energy inputs that use FF
machinery, harvesting, transport, processing, all require energy which likely comes from combusting FF
BUT biofuels release less emissions compared to FF
replace high NPP ecosystem for biofuels crop production
overall, NO
What is NPP
Net Primary Productivity
positives of biofuels
💚 manufacturing plants can employ hundreds of thousands of workers, creating new jobs in rural areas
💚 produced locally so decreases the nation’s dependancy on foreign energy, meaning countries can protect the integrity of their energy resources and make them safe from outside influences
💚 they’re cleaner to burn as they produce lots less c output and fewer toxins making them a safer alternative to preserve atmospheric quality and low air pollution
negatives of biofuels
❤️ have a lower energy output than other fuels so require larger quantities to be consumed in order to produce the same energy level
❤️large quantities of water are required for irrigation of biofuels crops as well as to manufacture the fuel ehcih could strain local and regional water resources
❤️ using valuable cropland to grow fuel crops could have an impact on the cost of food and could possibly lead to food shortages
radical tech - alternative to renewable energy: carbon capture storage (CCS)
captures carbon then stores in by artificial sequestration
phase 1 = capture (cc) in power stations and factories
phase 2 = stored (s) in depleted oil/gas fields, deep acquirers
radical tech - alternative to renewable energy: strengths of ccs
🟩 theoretically reduces co2 in atmosphere so c emissions can shift and be stored elsewhere
🟩 can do both co2 and ch4 at same time
radical tech - alternative to renewable energy: limitations of ccs
🟥 £££ - large-scale can cost $40B
🟥 high start up costs. try to decrease costs in North sea - oil rigs
radical tech - alternative to renewable energy: hydrogen fuel cells
fuel cells produce electricity through the reaction of a fuel with oxygen (o)
hydrogen oxygen fuel cells use hydrogen as their fuel and are useful in cars and spacecrafts
🟩water is the only waste product from a H-O fuel cell so less pollution
🟩 use of H-O in cars means no emissions of co2 from car so less reliance on FF
radical tech - alternative to renewable energy: electric cars
🟩 don’t use FF
🟥 BUT need FF to produce the energy
🟩 all FF are burnt in one power station which is practical as allows c capture
what % of Brazil’s energy comes from renewables
4%
households in the UK use ……% less energy
12%
what is the degradation of resources
changing the natural envi to suit needs of rising demands of pop.
happens in 3 ways:
1deforistation
2 reforistation and afforestation
3 grassland conversion
degradation of resources - deforistation
2015, 30% global forest cover = cleared
13M hectares deforisted annually
degradation of resources - reforestation and afforestation
reforestation = replanting deforisted trees
afforestation= planting treesnin new places w no prev deforestation
💚 it’s beneficial for co2 sequestration
❤️ but palm oil plantations often store less c, use more water and are disease prone
degradation of resources - grassland conversion
grasslands cover 26% global land
there are 2 types
1- temperate grasslands (most degradation)
2- tropical grasslands (land conversion is increased despite often infertile soils)
impacts of deforestation on the atmosphere 🏞️
🏞️ drier air
🏞️ less evapotranspiration (1/3 of TRF) so less humid and O content reduced
🏞️ reduced shading = more direct sunlight on forest floor = turbulence increases as the heated ground induces convectional air currents
impacts of deforestation on water cycle 💧
💧annual rainfall = reduced = evaporation from vegetation = reduced = infiltration = reduced
💧seasonality of rainfall increases = increased discharge leads to flooding = flood peaks = higher = shorter lag times
💧more eroded material is carried in river as bed load, silt and clay in suspension
impacts of deforestation on soil health 🌿
🌿 rapid soil erosion = loss of nutrients = increased leaching (loss of soil nutrients from infiltration) so minerals are lost
🌿raindrop impact washes finer particles of clay and humus away so coarser heavier sands are left behind
🌿 co2 = released from decaying woody material
impacts of deforestation on the biosphere 🌎
🌎less absorption of co2 so reduced c store
🌎 ecosystem services reduced - decrease in habitats = decreasevin species
🌎biomass reduced due to reduced plant growth/ photosynthesis
impacts on grassland conversion on the c cycle
less c stored in soil
initial removal of grasslands releases co2 from soil into atmosphere
reduced lung effect (less o2 produced) so less c sequestration as less co2
impacts of grassland conversion on water cycle
traps moisture and floodwater
biofuels crops = heavy consumers of water so need irrigation which has a significant effect on acquifers
impacts of afforestation on c cycle
trees provide a vital c store - sequestering c during photosynthesis
act as a terrestrial c store
monocultures store less c
less DOM in soil
impacts of afforestation on water cycle
more interception
less surface run off
define critical threshold
change in an ecosystem state where small envi changes cause significant responses and can lead to permanent damage
is the ocean a c sink or store?
sink
it’s one of the biggest c sinks
what are 4 factors that are pushing ocean ecosystems across a critical hreshold and towards permanent damage
temp (warming temps) - THC changes currents - changes salinity
extreme weather - changes corals - El Nino - more extreme
pH of water (acidification) - more co2 diffusing from atmosphere into oceans
pollution - micro plastics impact wildlife and c sequestration potential
threats to ocean health timeline. 6 points. 🥃🫧🥽🧪🎂🎃
🥃atmospheric co2 concentration and increases
🫧 more co2 diffusion into ocean
🥽 more c acid formations
🧪more acidic oceans as pH decreases due to more c acid
🎂excess of c acid = neutralised by bicarbonate ions
🎃 less bicarbonate ions to produce skeletons/shells/coals
ecosystems produce 4 services to us:
- supporting services - keep ecosystems healthy by providing other services, including soil formation, photosynthesis, nutrient cycling, water cycling
- provisioning services - the products obtained from ecosystems, including food, fibre, fuel, genetic resources, natural medicines, pharmaceuticals
- regulating services - including regulating air quality, climate, water, erosion, disease, pollination
- cultural services - the non material benefits that ppl obtain from ecosystems eg. spiritual well-being, recreation, education, science. eg. 100+ countries benefit from tourism in coral reefs
DAMAGE TO ANY OF THESE 4 = ecosystem risk = irreversible damage (due to critical threshold) = c stores lost
DAMAGE TO ANY OF THESE 4 = ECOSYSTEM RISK= IRREV due to criticalERSIBLE DAMSGEeshold = cstores los
what do mangroves do?
stabilise coastlines against erosion
if destroyed this affects water and erosion regulation
they collect nutrient rich sediment and ould affect nutrient cycle and food
provide nurseries for coastal fish away from predatos
threats to forests… (MEMORISE THIS!!!)
climat change will cause shifting climate zones
an estimated 2°C warming will shift about 5% of climates
another 2°C will shift a further 10%
CASE STUDY: drought in the AMAZON
Amazon holds 17% global c
forests act as global regulator -20Bn metric tonnes of water
droughts in the amazon are because of the Andies 🗻 and deforestation 🌳
★if drought and flooding events keep happening in the amazon, there will be no more rainforest due to the imbalance
