7.0 energy choices & security

energy security

availability to secure affordable, reliable, efficient energy for needs of a country

• depends on: technology, politics, economics, sustainability, environmental considerations

nuclear fusion

extracting heavy water from water and fusing 2 hydrogen atoms to make helium

low investment in renewables due to

• fossils are cheaper

• countries locked into trade agreements

• renewables are location dependant

bridge fuel

promoting natural gas consumption through oil/gas companies convincing governments get the country coal until renewables are developed

coal

+ cheap to burn, plentiful supply

- co2 (non-renewable), smog + lung disease

oil

+ high heat of combustion, once found = cheap

- oil spill danger, co2 emitted when burned

natural gas

+ cheap, cleaner than oil/coal

- leaked are dangerous, 30% cleaner than oil/coal

nucelar fission

+ no co2, small mass of radioactive material produced a lot

- high extraction costs, reactors are expensive

hydroelectric

+ good safety record, creates water reserves

- dams (ecological impacts), costly to build + run

biomass

+ cheap/readily available, if crops replanted: sustainable

- not replanted: unsustainable, burned = GHG

wind

+ green jobs, clean energy

- noise pollution, needs wind to blow

geothermal

+ infinite supply, used successfully in NZ

- expensive to set up, only volcanic activity areas

weather

daily result of changes in temp, pressure and precipitation in the atmosphere

climate

average weather patterns over many years for a location on earth

similarites between weather and climate

• affected by clouds

• forest fires

• volcanic eruptions

• human activites

differences between weather and climate

• timescale

gases include

• water vapor

• carbon dioxide

• CFCs

• HFCs

• nitrous oxide

• ozone

GWP

relieve masure of how much heat a known mass of GHG traps over a number of years compared to the same mass of CO2

GWP of different gases

• co2 = 1

• methane = 21

• nitrous oxide = 206

ozone in traposhere

GHG

ozone in starosphere

acts as a coolant

CFCs

chemicals made by humans

sources of methane

1. cattle

   • bacteria in stomachs that break down cellulous in the grass they eat

   • releasing methane as a waste product

   • solution = high sugar diet

2. tundra

   • permafrost melting releases methane (positive feedback loop)

impacts of climate change

1. oceans and sea levels

   • water expans and ice melting on land slips of into the sea

   • increases the volume of seawater (thermal expansion)

   • ocean buffering

   • country: MALDIVES

2. polar ice caps

   • melting of land ice (glaciers)

   • could open trade routes

   • make travel easier

   • allows exploration of undersea resources

   • undersea ice releases methane

   • country: GREENLAND & ANTARTICA

3. weather patterns

   • more heat means more energy in climate

   • weather will be more violent

4. food production

   • warmer temps increase photosynethesis

   • may be no increase in NPP

   • small increase in temp kill plankton

5. human health

   • algal blooms

   • red tides

   • asthma, chest infections

6. biodiversity and ecosystems

   • plants cannot move (extinction)

   • wildfires and droughts affect animals

   • increase in water temp can kill sensitive animals

positive feedback loop

amplifies change and does not return to steady state equilibirum, destabalize systems

negative feedback loops

dampens or reverses change returning to steady state equilibrium, stabilize the system

ex of positive feedback loop

• more evaporation leads to more clouds which trap more heat

• ice has high albedo which means that when it melts, it has low albedo and it absorbs more heat and more ice melts

• as temperature rises, permafrost melts and methane is released

ex of negative feedback loop

• warmer air carries more water vapours so more rainfall, some of which will be snow so more snow, more reflection, lower temperature, more ice

• forests absorb Co2 and act as a carbon sink to decrease temperature

mitigation

reduction/stabalization of GHG emissions and their removal from the atmosphere

adaptation

adjustment in natural or human systems in response to actual or expected climatic stimuli or their effects which moderates harm or exploits beneficial oppurtunities

mitigation strategies

1. stabalize or reduce GHG emissions

   • reduce energy waste by using more effectively (hybrid/electric vehicles)

   • changing lifestyle and business practices (public transport)

   • adopt carbon taxes and remove fossil fuel subsidy

   • reduce methane production (change cow diets)

2. remove Co2 from atmosphere

   • increase photosynthesis

   • carbon capture and storage

   • use more biomass as a sorce of fuel

3. geoengineering

   • release sulphur dioxide from airplanes to increase global dimming

   • send mirrors to space between the earth and sun to deflect solar radiations

   • build with light colored roofs to increase albedo and reflect more sunlight

adaptation strategies

1. change land use through legislation

2. build to resist flooding

3. change agricultural production (rainwater harvesting, growing diff crops, drought resistant crops)

4. managing the weather (planting trees)

5. migrating to other areas

6. managing water supplies

7. vaccination against water borne diseases