Explain where the sand on the beach comes from, and how the beach changes over the year
- Sand is from eroded sediment from mountains and rocks carried by wind, water, glaciers, etc
- Sand is transported by a littoral cell, entering at a river mouth and moving along the beach
- Summer: broad, gentle slope, sandy, calmer waves
- Winter: narrow, steep slope, rocky from sand moving offshore, high energy waves
What is the difference between conventional petroleum and tar sands/oil shales in a) the nature of the petroleum and the tar, b) how the resource is extracted and c) how expensive it is to produce?
- conventional petroleum: found in rocks, requires mining, least expensive form of energy
- tar sand/oil shale: solid petroleum, requires mining/fracking, water-intensive recovery, but economic
Describe a) how petroleum forms and b) what two properties make a good reservoir rock for conventional petroleum
- how petroleum forms: compressed planktonic organisms under heat and pressure, takes millions of years to form, degree of heat and pressure determine type of petroleum produced
- 2 properties for good reservoir: high porosity (lots of pore space to hold oil), high permeability (allows oil to flow out)
What is the difference between hydraulic fracturing (fracking) and conventional oil drilling? Why are environmentalists concerned about fracking? What are the advantages of fracking?
- difference: horizontal drilling instead of straight up and down, use high pressure water to blast holes in rock, pump down solvents to release gas
- concerns: groundwater contamination, unregulated, cause earthquakes, ensures use of carbon-emitting energy
- advantages: allow US independence for energy, natural gas has lower carbon footprint than oil, cleaner than coal, less pump stations required
What is the difference between passive and active solar heating?
- passive: use design features of home to use sunlight in winter and shade in summer
- active: systems actively collect solar energy for heating or electricity
What is the difference between nuclear fusion and nuclear fission? Which one do we use to generate electricity? Why?
- fusion: fusing smaller atoms into one larger atom, clean waste products, requires more energy to generate than it yields
- fission: splitting atoms to release energy and particles, results in radioactive waste
Why is it difficult to reliably assess the true costs of using nuclear power? What additional costs that must eventually be paid are not included in the cost of electricity generated using nuclear reactors?
- the cost of creating electricity does not include the cost of disposal/decommissioning of nuclear waste
- total health risks/increased cancer risk from accidents are difficult to prove
Describe three ways hurricanes do damage and three ways to protect against hurricane damage
- damage: wind/tornados, storm surge, flooding
- protect: better building standards (secure & improve roof, steel frames), zoning to alter type of construction, insurance to help repair damage
- How hurricanes develop and where they get their energy
- What makes hurricanes get stronger, and what makes them weaken
- What effect climate change may have on hurricanes in the future
- development: warm moist air over water rises & condenses, heat is released, more air rises, lower pressure center created, begin to spin
- stronger: condensation, hurricane gains energy
- weaker: evaporation, hurricane loses energy
- climate change: rising sea level and temp results in higher frequency, higher intensity
Why will maintaining sufficient water supplies for the American West be more challenging in the future?
What are the political and environmental challenges of maintaining an adequate water supply?
What are state and local governments currently doing to help meet this challenge, and what should be done in the future?
- Challenge in maintaining sufficient water supplies:
- Snowpack in CA is decreasing
- Snowpack is a huge reservoir of fresh water for CA
- Climate belts are shifting, causing less precipitation overall and longer, drier summers
- CA will need to look for alternative water sources if current conditions continue because the state is acquiring less and less fresh water
- The current amounts of fresh water will not be enough to keep up with increasing population trends
- Political & environmental challenges of maintaining water supply:
- Regulating water use will cause political backlash with citizens and farmers
- Limiting agricultural water use will cause economic declines and more political backlash with farmers and politicians
- Over-pumping groundwater to maintain a constant supply of water can result in land
- Current actions, future actions:
- Currently working on enacting contamination cleanup and increasing regulation and identification of heavy water use
- New technology requiring less water usage for things such as toilets, washing machines, etc
- Some parts of CA are investing in desalination of ocean water to produce fresh water
Discuss new petroleum sources: What are the advantages? What are the risks?
Compare two sources of energy: one conventional (petroleum, coal, nuclear), and one alternative (solar, wind, geothermal, wave/tidal). In your comparison, consider:
-potential costs of all kinds (economic, environmental, health, strategic)
- any limits on the resource, or potential for expansion
Recommend future action with respect to these three energy sources (new petroleum, your conventional sources and your alternative source.
- Petroleum sources:
- Petroleum sources are among the least expensive forms of energy
- There are different types of hydrocarbon resources
- Oil sands provide a large reservoir of resource but we do not have the technology to extract it
- Oil shales require fracking to extract the gas and can be very damaging to the environment, but it less carbon-emitting than other forms of oil
- Methane hydrates are another large reservoir but the risk of extraction currently outweighs the benefit, since the gel is potentially
- explosive and could release massive amounts of methane into the atmosphere
- Coal vs Wind:
- Coal is very cheap to produce but also the most polluting source of energy
- Acid runoff, acid rain, strip mining, air pollution, and fly ash are all damaging to the environment
- Strategically, the US has the world's largest known reservoir of coal
- Limiting factors for coal include the challenge of transportation and the time required to create more coal, making it a non-renewable source
- Wind is inexpensive with little risk, except to workers
- Wind power is nearly carbon-free, but can be a hazard to birds and bats as they fly into the blades
- Strategically the US is able to make their own turbines, requiring very little import
- Limiting factors include locations only with high, consistent winds; efficiency in transporting electricity; and requires a back-up supply of energy in case there is no wind to turn the turbine
- Non-renewable sources need to be cut out since they are not dependable indefinitely
- and tend to be more polluting than alternative energy
- The use of coal needs to be eliminated since it is the most hazardous to health and the environment
- Relative to the other two, wind is the best
- source of energy since it is cheap and clean.