Topic 1 - Water and carbon cycles Flashcards
Define input in terms of a system
Give a drainage basin example
Material or energy moving into the system from the outside
Eg precipitation
Define output in terms of a system
Give a woodland carbon cycle example
Material or energy moving from the system to the outside
Eg dissolved Carbon in runoff
Define stores in terms of a system
Give a drainage basin example
Individual parts of a system
Eg trees, puddles and soil
Define transfers in terms of a system
Give a woodland carbon cycle example
relationships/links between the components
Eg burning of fuels and absorption of carbon
by trees
Define positive feedback
Cyclical series of events that amplify change, often promoting environmental instability
can lead to tipping points where change becomes unpredictable
Define negative feedback
cyclical sequence of events that promote stability and state of equilibrium in a system
Open/closed systems
Water + carbon cycles
On a global scale, both are closed systems as there are no loses/gains from space
On a local scale they are both open systems, water can enter and leave, there are flows like throughflow of water and photosynthesis which uses carbon
Define system
Consist of components, flows and transfers and the relationship between them
Cryosphere store of water
Water stored in frozen areas of the earth:
Glaciers
ice sheets
frozen parts of the ocean
Lithosphere store of water
Water stored on solid outer crust/mantel
Stored within rock structures in oceanic crust
Stored in rocks, minerals and clay as groundwater.
Hydrosphere store of water
Water stored on the surface of the planet oceans rivers lakes ponds
Atmosphere store of water
Water stored as gas surrounding planet
clouds
microscopic particles of water
Water store states
Saline/freshwater stores
- 5% is saline water, most of which is in the oceans.
- 5% is freshwater, most of which stored as ice/snow or as groundwater
Surface freshwater only makes up 1.7% of all freshwater.
Define aquifers
Reservoirs of freshwater stores deep under ground surface
Types of rock in aquifers
Porous rocks tend to transfer more water than store.
Clay soils tend to store more water than transfer.
Water table
Upper level of saturated rock.
Rises/falls in response to:
- Ground water flows
- Abstraction by people
- Recharge, flow of additional water into reservoir
Fossil aquifers + few locations where they are found
Aquifers formed thousands of years ago when current desert climates were once wed:
- Africa
- Middle East
- Australia
Transfers that affect magnitudes of water stores define: Overland flow infiltration throughflow percolation Groundwater flow
Overland flow: Transfer of water over land surface
Infiltration: Transfer of water from the ground to soil
Throughflow: Water flowing through soil to river channel
Percolation: Water soaking into rocks
Groundwater flow: slow transfer of water through rocks
3 stat based facts about historic climate change
- 1800 years ago 1/3 of earth was covered in ice (glacial period)
- Sea levels during this time dropped 100m compared to present day
- 3 million years ago (interglacial period) sea levels were 50m higher compared to present day.
Define glacier and ablation
Glacier is a body of ice moving under its own weight, forms when accumulation exceeds ablation.
Ablation is the natural removal of snow by melting or evaporation.
Water balance
Equation
P = Q + E +/- S P = Precipitation Q = Total runoff E = Evaporation S = Storage in rocks/soil
Flashy hydrograph \+ 3 DB or precipitation characteristics (size of basin land-use rock type)
Short lag time/high peak discharge
- Size of basin, small basins often lead to rapid water transfers.
= Land-use, urbanisation encourages rapid water transfer. - Rock type, impermeable rocks encourage rapid overland flow
Flat hydrograph \+ 3 DB or precipitation characteristics (relief soil water rain intensity)
Usually longer lag time/lower peak discharge
- Relief aka build of the land, soft slopes = slower transfers
- Soil water, dry soil soaks up water = slow transfers. Baked soil can encourage rapid transfers
- Light rain will transfer slowly
Greenland ice-sheet
1 fact + physical cause of melting (Early melt)
Contains 8% of earth’s freshwater
Early glacial melting
- Melting in summer months has been occurring earlier
thought to be caused by rising temperatures.
- In 2016 17% of surface ice melting in a few days.
Greenland ice-sheet
1 fact + human impact of melting (environmental refugees)
If it melted, seas would rise by 24ft
Environmental refugees
- If ice-sheet further melts, sea levels will rise endangering coastal areas.
- 1/3 of the world lives in coastal areas.
- Would result in billions of refugees affecting societies and economies.
Drainage basin
2 physical factors that affect components of a DB
(Which affect stores/flows in a DB)
(Vegetation/precipitation intensity)
Vegetation: More vegetation means more evapotranspiration, more slow, stem flow. This decreases rapid surface runoff and peak discharge.
Precipitation intensity: intense storms = intense precipitation which leads to high peak discharge, flows intensify as input intensifies.
Drainage basin
2 human factors that affect components of a DB
(Which affect stores/flows in a DB)
(urbanisation/water abstraction)
Water abstraction: Increased abstraction to meet population demand as population increases results in more abstraction, depleting the stores from rivers/groundwater aquifers
Urbanisation: Permeable surfaces are replaced with concrete meaning infiltration is not possible, this increases overland flow increases and lag time reduces increasing flood risk
Soil water budget
What happens to soil in WINTER
- Precipitation exceeds evaporation resulting in a water surplus
- Soils are saturated, field capacity is reaches increasing overland flow.
- Higher river levels
Soil water budget
What happens to soil in SUMMER
- Evaporation exceeds precipitation, soils dry out.
Soil water budget
What happens to soil in AUTUMN
- Evapotranspiration reduces
- Soils are recharged
Define field capacity and drainage basin
Field capacity: Maximum volume of water soil can hold without any outputs occurring
Drainage basin: Area of land drained by a river and its tributaries
1 physical factor affecting change in the water cycle
Seasonal
Winter seasonal changes:
- Vegetation dies back reducing interception/transpiration.
- Colder temp = less evaporation
- Saturated soils/frozen soils encourage overland flow
Summer seasonal changes:
- Less total rainfall/more frequent storms
- Vegetation grows rapidly, increasing interception/transpiration
- Dry soils encourage infiltration, baked soils however encourage overland flow
2 human activities affecting change in the water cycle
farming practices/abstraction
Farming practices:
- Irrigation for crops increases transpiration, infiltration of their soils and greater soil stores
- Desertification reduces soil capacity to store water
- Irrigation removes water from other stores, increases as demand rises (more crops needed etc)
Water abstraction
Name the largest and smallest carbon stores + how much they store
Marine sediments/sedimentary rocks
Long term store
100 000 metric tonnes
Terrestrial plants
Carbon used for photosynthesis and stored as biomass in plants
560 metric tonnes
Explain soil formation
hint: starts with weathering
- Rock is slowly broken down, carbonate rocks release carbon, often dissolved in water over time.
- Vegetation like moss forms on bare rock, carbon exchanges like photosynthesis/respiration take place.
- Over time more vegetation is added to rock fragments forming soils.
Mangrove soils as carbon stores
- Found along the tropic and subtropical coasts of Africa/Asia.
- Serquest almost 1.5 metric tonnes of carbon per hectare annually.
- Soils are anaerobic meaning decomposed matter is not returned as carbon to the atmosphere.
CARBON CAN BE STORED FOR MANY YEARS.
Tundra soils as carbon stores
- Frozen soils contain ancient carbon
- Microbe activity only occurs on surface layer when it thaws, majority of time decomposed matter is frozen
- Carbon remains locked for many years.
Transfers in the Carbon cycle
CCS (human)
Carbon capture and storage
- Tech captures carbon emissions from coal factories
- Traps, transports and stores carbon deep underground.
- Predicted to reduce 90% of carbon emissions from powerplants.
Transfers in the Carbon cycle
Decomposition (physical)
Decomposition
- Bacteria/fungi breakdown complex carbon compounds from dead animals/plants into simple ones, releasing them into the atmosphere.
- If Oxygen is not present, methane is released.
Transfers in the Carbon cycle
Weathering (physical)
The breakdown or decay of rock in their original place:
- Carbon absorbed by rainwater turns it into a slightly acidic carbonic acid.
- Rocks will slowly dissolve, with the carbon being held in solution.
- Transported to seas via water cycle, it can then be used by organisms to make shells etc.
Transfers in the Carbon cycle
Burial and compaction (physical)
- Corals and shelled organisms use carbon to make skeletons, once they die some carbonates dissolve releasing CO2, others fall to the seabed forming limestone.
- organic matter is buried by ocean sediments, becomes compacted.
- After millions of years, carbon containing sediments form hydrocarbons like oil/coal.
Physical causes for change in the carbon cycle:
Temperatures influence carbon levels
Impact of cold conditions
- More chemical weathering as cool oceans hold more carbon dioxide
- Decomposers less active = less transfer of carbon to/from soils
- Frozen soils = less carbon transfers, more storage
Physical causes for change in the carbon cycle:
Temperatures influence carbon levels
Impact of warm conditions
- Recently global temperatures have risen, noticeable in higher latitudes where tundra ice is melting.
- GHGs like CO2 and methane being released, enhancing greenhouse affect creating positive feedback of more ice melt.
Physical causes for change in the carbon cycle:
Volcanic activity
- Released carbon into the atmosphere that has been trapped for millions of years deep in earth’s crust
- 524/252 years ago volcanoes were more active, they released vast amounts of CO2 which remains still
- Today volcanoes release 130 million tonnes/year, humans release 30 billion tonnes/year from fossil fuels
Volcanoes release lava containing silicates, as they weather they remove CO2 from the atmosphere and convert them to carbonate solutions
Snow-ball earth
700 million years ago ice advanced from the poles covering the surface with ice.
Human causes for change in the carbon cycle:
Farming practices
Ploughing, rearing of livestock, use of fossil powered machines etc
- On farms main source of emissions = fertilisers
- Cattle in USA release 5.5 million tonnes of methane/year. (20% of methane emitted from USA)
- Rice may contribute to 20% global methane production.
Human causes for change in the carbon cycle:
Urbanisation
- Urban areas make up 2% of the earth surface, but is responsible for 97% of carbon emissions
- Major sources = transportation/industrialisation
Clinker, a component of cement is responsible for 2,4% global carbon emissions
Importance of oceans (generally)
Regulate global climate:
Absorbs heat and transports warm oceans from the equator to the poles, and cold water from the poles to the tropics.
provides jobs
59 million people worked in aquaculture/fishing.
Important habitat
Marine ecosystems under threat, oceans becoming warmer and more acidic.
Importance of oceans in terms of carbon/heat absorption
Contain 50x more carbon that the atmosphere.
absorb 35-42% of carbon from atmosphere, and 90% of excess heat caused by rising greenhouse gases.
Define thermocline
Gradient which separates warm surface layer of water heated from the cooler, denser water in the deep ocean.
Arctic ice feedback loop
Positive feedback:
- More CO2 in air traps more heat
- Warmer temperatures causes melting of permafrost
- Release of GHGs, enhances greenhouse affect
- More GHGs trap more heat, further melting of permafrost
Arctic sea-ice feedback loop
Positive feedback
- CO2 causes more heated climate
- Warmer temperatures melt ice, reducing reflective surface ice
- Reduced albedo affect, less sunrays reflected to space
- Darker ocean surfaces reflect less sun, warmer oceans further melt ice and store less CO2
Phytoplankton feedback loop
Negative feedback
- More CO2 traps more heat in oceans
- Warm oceans promote phytoplankton growth
- increased release of DMS from phytoplankton results in more cloud formation
- Cloud block sun + dampen climate, cool earth
How reliant are the water/carbon cycles on eachother
Carbon cycle is entirely reliant on water cycle, without water carbon could not be transferred to various spheres
Water cycle is independent of carbon cycle, only driven by sun and gravity
Define equilibrium
State of balance within a changing system
Role of oceans in carbon sequestration
Physical carbon pump
How carbon is dissolved in oceans and moved by currents
- Downwelling: Denser cooler ocean currents transfer carbon to deep oceans, carbon remains dissolved there
- When current meets coast there is upwelling, carbon is released from solution to the atmosphere
Role of oceans in carbon sequestration
Biological carbon pump
Phytoplankton absorb CO2 from atmosphere, marine creatures absorb carbonate compounds to make shells
- Calcium bicarbonate dissolves allowing marine creatures to extract carbon compounds to make shells
- Shells form to the ocean floor and accumulate as carbon deposits
- Marine sediments lithify into carbon rich rock, entering slow carbon cycle
- Phytoplankton absorb CO2, they die and fall as marine snow, accumulating as carbon deposits
Role of oceans in carbon sequestration
Carbonate pump
Carbon enters oceans directly through precipitation, or rivers containing eroded/weathered carbon rich rocks
- River discharge: weathering of carbon rich rock like chalk creates soluble carbonate solution can enters seas
- Precipitation: Water vapour and CO2 combine to form acid rain, can fall directly into seas or slowly weather carbon rich rock
Climate change
Climate change does not cause extreme weather events, it increases the frequency at which they occur
(FLIP FOR FACTS)
- Met office, US Climate Centre and NASA identified trend of increasingly warmer climate
- 20 of the hottest years on record occurred in the last 22 years
- Global temp increased by 1°C since industrial revolution
- By the end of the decade: estimated 3-6°C temperature increase, 80cm sea level rise
Climate change
Socio-economic impacts
- 24 billion dollars worth of damage due to extreme weather could arise
- Trade relies on coasts/90% on oceans
- 600 million people live in coastal areas
- Food production will be heavily impacted, LDEs will take the brunt of the damage
Climate change
Environmental impacts
- 8% of species at risk of extinction
- 2018 Australia, 11 thousand bats died due to heat, 2 more events of this kind as they will be extinct
- Record breaking fires in Australia, Greece and the Arctic
Climate change (mitigation/adaption) Modifying photosynthesis
- Some plants are better at absorbing/storing carbon than others, replanting the same species protects biodiversity
- However best carbon sinks takes too long to grow
- Replanting however has been recognised by the IPCC as a legit way to reduce CO2 emissions
Climate change (mitigation/adaption) Modifying farming
Carbon farming: replacing crops with efficient crops that absorb more CO2
- Organic mulch can be left on large plantations to refuel the carbon cycle in the soil rather than allowing it to escape.
Climate change (mitigation/adaption) Renewable energy sources
- Solar power is the cheapest newly installed energy in 60+ countries
- UK building largest offshore wind turbines, one revolution can power a house for a day.
- 30% of UK’s energy supplies by renewable sources
Meat + climate change
FLIP FOR KEY FACTS
- 80 billion animals eaten/year
- 400 million cattle increase in 50 years
- 30 billion of pig manure/year, can contaminate water with e-coli
- 20% Amazon lost to cattle activity
- 40% global crops grown to feed animals
Meat + climate change
Why is meat a threat to our earth
(Cattle producing methane, loss of biodiversity, increasing demand)
Cows release methane, 30x stronger as a GHG compared to CO2
Monoculture for agriculture causes loss in biodiversity which can cause a ripple affect through a food chain
by 2050 demand for meat will increase by 40%
