Module 7 HSC Revision Flashcards
What are the relative timescales of the PTSC, volcanic eruptions, changes in Earth’s orbit and ocean circulation in terms of global climate change
PTSC - millions/tens of millions of years
Ocean circulation - as above since they are linked
Volcanic eruptions - tens of thousands/millions of years
Changes in orbit - tens of thousands/hundreds of thousands of years
How do changes in rock type provide evidence of ancient climate variations
Coal <- wet climate for fossilisation
Dropstones (from glacial ice melt) indicate a cool dry climate
How do ice cores provide evidence of recent climate variations
- Gas bubbles indicate the composition of the atmosphere (e.g. hydroxyl radicals which determine methane)
- Volcanic ash layers can be radiometrically dated
- O-18 and O-16 ratios
How do speleothems provide evidence of recent climate variations
- Growth rings indicate climate changes
- O-18 O-16 isotopes (long-term O-18 changes indicate temperature change, short term = humidity)
- Can use uranium-thorium dating to date the years of the rings
How does land use and land cover change cause the enhanced greenhouse effect
- Land clearing + deforestation releases CO2 rather than sequestering it
- Fertiliser use leads to increased nitrogen in the nitrogen cycle (nitrogenous gases = GHGs)
- Methane from agriculture
How can we minimise CO2 emissions as individuals?
- Food consumption of a more plant-based diet due to the carbon-intensive nature of meat production
- Creating carbon sinks, e.g. community gardens
- Voting and political awareness
What is urban design and what are examples of adaptation and mitigation strategies
Urban design is used in individual houses, communities and whole cities, and act as BOTH adaptation and mitigation strategies
- Insulation (using hay bales) is ana adaptation against rising temperatures
- Trees - cooling is both adaptation and mitigation (transpiration, provides shade, carbon sink)
- Moving away from concrete and towards carbon storage/sink materials such as timber
What is geo-engineering and what are examples of adaptation and mitigation strategies
Geo-engineering is the use of engineered interventions in to reduce the amount of
light reaching Earth’s surface or reduce the amount of CO2 in the atmosphere
- Afforestation/reforestation (mitigation)
- CCS in ground and oceans (however this has not been implemented on a large sca;e and in the ground there is a chance of carbon leakage/escape)
- Solar engineering by injecting stratospheric SO2 and aerosols into the atmosphere to increase the albedo effect (however this destroys the ozone layer and causes acidic rain)
What are the strengths and limitations of nuclear fission
Strengths: Reliable, doesn’t produce emissions
Limitations: Mining uranium, safety factors of the radiation and waste product disposal
What are the strengths and limitations of wind power
Strengths: Renewable, lots of opportunity in Australia due to coastal locations
Limitations: Turbines are reliant on weather and are therefore not 100% reliable
What are the strengths and limitations of geothermic power
Strengths: Natural movement of energy
Limitations: Volcanic hazards, only works in areas with volcanic activity, needs the right conditions
What are examples of ATSI adaptation and mitigation techniques
- Use of seasonal calendars to sustainably manage food sources
- Can also talk about fire or totems
What are mitigation strategies
Mitigation strategies involve reducing the flow of greenhouse gases into the atmosphere (“climate-friendly”)
What are adaptation strategies
Adaptation strategies involve helping individuals and communities deal with the effects of climate change (“climate safe”)
