water, carbon, climate and life on earth Flashcards
Water and carbon cycles and the atmosphere
- Increased emissions of Co2 is warming the atmosphere increasing temperatures increasing evaporation rates and a wetter atmosphere, leads to a positive feedback situation of further warming
- CO2 causes about 20 per cent of earths greenhouse effect, water vapour about 50 per cent, and clouds 25 per cent, rest small particles (aerosols) e.g methane
- Although CO2 contributes less to overall greenhouse effect than water vapour, scientists found that CO2 sets temperature. Controls amount of water vapour in atmosphere and therefore size of enhanced greenhouse effect.
- there is time lag between increase in CO2 and increased warming because ocean absorbs heat
Climate change mitigation
- Improving aviation industry: shorten flights, change routes, improve fuel efficiency
- Change rural land use: Afforestation, changing agricultural methods e.g non-ploughing
- Urban design: Waste management plans e.g capture landfill gas, recycling, green roofs
- Increased use of renewable energy: wind power, solar energy, wave and tidal power
Carbon Capture and sequestration (CCS) technologies name three parts
Capturing: allow separation of CO2 from gases produced i electricity generation and industrial process by one of these methods: pre-combustion capture, post-combustion capture and oxy-fuel combustion.
Transporting: CO2 by pipeline or ship to storage location e.g for commercial purposes
Storing: CO2 emissions undergrounds in depleted oil and gas fields, deep saline aquifer formations kilometres below surface or deep ocean
CCS- Land stored
- CO2 is converted into a high pressure liquid-like form known as ‘supercritical CO2’ behaves like a runny liquid
- This is directly injected into sedimentary rock
- Geochemical trapping mechanisms prevent CO2 from escaping to surface
- Could be in old fields, gas fields, saline formations and thin coal seams
Saskatchewan- called Boundary Dam how does that take up CO2
- Coal fired power station complex that has been retrofitted to capture 90 per cent of its CO2 output
- CO2 eventually be piped 66 km to Weyburn Oil unit and injected into an oil-bearing formation at 1,500 m depth
- Add pressure to oil-bearing rock so help push more oil out of ground- enhanced oil recovery (EOR)
- Until that is ready it will be injected into local salt formations
- $800 million to build CCS unit, consumes 21 per cent of the coal planet’s power output in order to scrub out carbon dioxide and compress it into liquid form for burial.
Changing rural land use- mitigation schemes
Grasslands can be improved by:
- Avoidance of overstocking of grazing animals
- Adding manures and fertilisers that have direct impact on soil organic carbon (SOC) levels through added organic material. Benefit increasing plant productivity and stimulating soil biodiversity e.g earthworms help degrade and mix organic material)
- Revegetation using legumes, can increase productivity, resulting in more plant litter and underground biomass
Croplands techniques for increasing SOC:
- Mulching can add organic matter, if crop residues are used, mulching prevents carbon loses from the system
- Reduced or no tillage avoids accelerated decomposition of organic matter and depletion of soil carbon that can otherwise occur.
- Use of animal manure or chemical fertilizers increase plant productivity.
Forest lands and tree crops:
- Protection of existing forests will preserve current soil carbon stocks
- Reforesting degraded lands
- Trees in croplands and orchards can store carbon above and below ground. CO2 emissions can be reduced if they grown as a renewable source of fuel
Improved aviation practices
- Movement management: avoiding circling, adopting fuel efficient routes
- Flight management: 100% occupancy of seats, cruising at lower speeds
- Design and technology: Increased engine efficiency, increased use of bio-fuels, reduced weight of aircraft and engines
