Module 7 Flashcards
Pollen grains in sedimentary rock (AE)
- Distributed by winds → fossilised at bottom of lakes/bogs
As climate + environment around lake changes, so does composition of pollen preserved in lake sediments
→ looking at composition of pollen to identify plant species and relate to climate, eg. alpine pollen = cold climate
Pollen grains do not provide global temp → only LOCAL
Rock types and formations (AE)
- Vast chalk deposit in White Desert at Farafra depression
- Chalk- limestone composed of calcite
- Process of glaciation
- Surface exposure dating
Fossils and microfossils (AE)
- Fossil reefs, stromatolites, limestone deposits, Ediacaran fossils and sand ripples found in Australia.
- In SA, Cambrian limestone in Normanville on Fleurieu Peninsula.
Changing isotope ratios in rocks and deep sea sediments (AE)
- O-16 evaporates first into atmosphere = tropic oceans rich in O-18 molecules
- O-18 molecules precipitate/condense at lower, mid latitudes
- Evaporated O-16 molecules travel via clouds towards pole, then precipitates as snow
- O-16 trapped in glaciers during cooler periods
- When climate becomes warmer, O-16 rich glaciers melt back into the ocean, increasing ratio of O-16:O-18
Ice cores (RE)
Warmer periods = more O-18 isotopes in frozen H2O = changes in snow fall from high to lower levels
- Winter seasons indicated by darker layers in ice core
- Summer is indicated by lighter layers
Dendrochronology (RE)
- 1 ring = 1 year of growth in an oak tree
- Scarring in rings = fires
- Disfigured rings = uneven growth from lack of sunlight
- Measure rings across several trees to reveal matching patterns (cross-dating)
Dendrochronology 2 (RE)
- Growth directly affected by surrounding conditions
- Indicates seasons in which growth was poorer/better helping infer climate conditions
- Captures climate conditions from periods older than tree life
Aboriginal art sites (RE)
- Now extinct species/environments recorded in form of rock painting
- Aboriginals in Aus for 50,000 years > - witnesses to changes in climates, ecosystems, native animals
- Art sites preserve iconic megafauna eg. Procoptodon
Human instrument records (RE)
- Thermometers measure atmospheric temperature
- Models predict effects of future climate change
- In past decade, human record of predictions have nearly all come true (most accurate form of data)
Changing isotope ratios in coral (RE)
- Calcium carbonate layers in their growth- rate read to show salinity, pH, temp
- Skeletal cores in UV/X-ray captures differences in growth rates through coral life
- Increasing pH creates stress by eating away at skeleton
Stalactites
Hanging in ceiling
Stalagmites
Growing from ground up
Isotope ratios in stalactites and stalagmites (RE)
Sampling their O:16-O:18 ratio provides info on their temp + growth rates reflect rainfall activity
Natural greenhouse effect
Some solar energy reflected back into space, some absorbed by GHG- this traps heat to warm atmosphere. This:
- Regulates average temp. to allow survival.
- Temp influenced by ice ages, interglacial periods every 100,000 years
Anthropogenic greenhouse effect
Fossil fuels, agriculture, growing populations
^^ increases GHG levels in atmosphere
- Temp rise by approx. 0.7 degrees since 20th century
- Increased ozone creates smog in city +blocks UV radiation
Influence of increasing GHG
- Biomass burning
- Methane (fossil fuel + livestock)
- Carbon dioxide (deforestation)
Ocean acidification (OA)
Acidity changes in ocean as CO2 in atmosphere dissolves in water, lowering pH.
Influence of ocean acidification (OA)
Since Industrial revolution, OA increased by 30%
1. Coral porosis = dissolution of coral itself - disease attacks skeletons on dead coral
2. Collapses reefs, affecting ecosystems
3. Cracked therapod shells exposure to predators
Changing weather patterns (flow on effect)
More heat in atmosphere increases evaporation +convection, which changes climate systems.
This affects land + ocean temp, rain/snowfall, intensified bushfires/cyclones
Changes in glaciers, sea ice, ice sheets (flow on effect)
Melting glaciers:
Rising + warming sea levels, disrupted ocean circulations.
1. Destructs coastal erosion/communities, intense coastal storms
Less ice forming:
1. Decreased breeding grounds + algae = limited food supply chain
2. Reduced albedo effect = ocean salinity, coastal erosion
Changing range of species due to rising sea
level
Loss of land + coastal erosion:
1. animals cannot migrate due to natural borders + threatened ecosystems die
- Loss of mudflats /marshes which remove habitats for invertebrates = less food supply and therefore species extinction
eg. Dugong (northern AUS)
- Relies on reduced food source (seagrass)
→ rising sea levels reduce distribution of seagrass, shrinking population
Burning of fossil fuels
Caused by size of population and standard of living.
1. Power stations are coal-driven.
2. Largely used energy for transport
Land use and land cover change
Agriculture uses:
1. Fertilisers
2. Ruminant animals
3. Land clearing
4.Tilling/ ploughing
All contributes to nitrous oxides and carbon dioxides in atmosphere.
Minimisation of GHG by humans in daily lives
- Eating less meat + buying local products
- Electric/hybrid cars
- Use of public transport
Urban design (mitigation)
- Double glazing (insulation)
- Efficient public transport
- Green buildings
Eval. of insulation:
- Reduced electricity bills
- Less air conditioner noise
- Expensive to construct
- Difficult to retrofit in exisiting homes
Urban design (adaptation)
- Elevated houses
- Sea walls
- Light surfaces reduce albedo effect
Eval. of elevated houses:
- Money saved in long run
- Easier cleanups after floods/ avoids damage
- Expensive to implement
- Requires zoning laws/building code approval
Geosequestration (Geo-engineering- mitigation)
Captures CO2 from major power stations and injects them into geological formations, locking it away.
Evaluation:
- Reduces CO2 in atmosphere
- Benefits soil quality
- Unknown long term effects
- Risk of leakage
Solar energy/ solar panels (alternate energy sources)
Pros:
- Sustainable
- Little maintenance
- Lower electricity bills
Cons:
- Inconsistent energy source
- Expensive to install
- Incompatible with certain roof types
Therefore should be paired with other energy sources to meet electricity demand.
Hydroenergy/ hydroelectric dams (alternate energy sources)
Generates electricity as water passes through turbine.
Pros:
- Renewable + sustainable
- High efficiency (90% vs coal at 25%)
- Reliable (can meet peak demands due to actively flowing rivers)
Cons:
- Susceptibility to drought
- May obstruct fish migration, water temps. + ecosystem around river
Agricultural practices of Aboriginal/ Torres Strait Islander peoples
Mosaic burning:
Lighting low fires in small areas manually to burn underbush.
1. Opens native seeds
2. Encourages native animals to migrate then come back to new growth
Insect diet:
1. Replacement of meat- reduces carbon footprint.
2. Higher in protein
3. Bogong moth- nutritious source eaten by Aboriginals
