Comprehensive Study Guide for Global Climate Change and Energy Resources

Chapter 14: Global Climate Change

Key Terminology and Definitions

• Climate: The long-term pattern of atmospheric conditions, including temperature, precipitation, humidity, and wind, in a specific region over periods ranging from decades to thousands of years.
• Climate Change: A systematic change in the long-term state of the earth's climate, including significant variations in temperature, precipitation, and wind patterns, often driven by human activities like fossil fuel combustion and deforestation.
• Greenhouse Gases (GHGs): Atmospheric gases that absorb and re-radiate infrared radiation, trapping heat in the troposphere. Examples include carbon dioxide ($CO_2$), methane ($CH_4$), nitrous oxide ($N_2O$), and fluorinated gases.
• Greenhouse Effect: A natural process where greenhouse gases absorb heat escaping from Earth's surface and re-emit it, warming the lower atmosphere. Without this effect, Earth's average temperature would be approximately $-18^{\circ}\text{C}$ rather than the current $15^{\circ}\text{C}$.
• Aerosols: Microscopic droplets and particles (such as soot or sulfur dioxide) suspended in the atmosphere that can either have a warming or cooling effect on the climate by reflecting or absorbing sunlight.
• Radiative Forcing: The change in the energy balance of the Earth (the difference between incoming solar radiation and outgoing infrared radiation) measured in watts per square meter ($W/m^2$). Positive forcing leads to warming; negative forcing leads to cooling.
• Milankovitch Cycles: Three types of periodic changes in Earth's orbit and tilt (eccentricity, obliquity, and precession) that alter the distribution and intensity of solar radiation reaching Earth, triggering long-term climate shifts like ice ages.
• Proxy Indicators: Indirect evidence of past climate conditions used by scientists to reconstruct historical climates. Examples include ice cores, tree rings, sediment cores, and coral reefs.
• Climate Models: Sophisticated computer programs that use mathematical equations to simulate the interactions of the atmosphere, oceans, land surface, and ice to predict future climate scenarios.
• Intergovernmental Panel on Climate Change (IPCC): An international body of scientists and government officials established in 1988 to provide objective scientific reports on climate change, its impacts, and mitigation options.
• Ocean Acidification: The process by which the ocean's $pH$ decreases as it absorbs excess atmospheric $CO_2$, forming carbonic acid ($H_2CO_3$), which harms marine life, particularly organisms with calcium carbonate shells.
• Mitigation: Actions taken to reduce the severity of climate change by reducing greenhouse gas emissions or enhancing carbon sinks (e.g., switching to renewables, reforestation).
• Adaptation: Strategies designed to minimize the impact of climate change on human and natural systems (e.g., building sea walls, developing drought-resistant crops).
• Carbon Footprint: The total amount of greenhouse gases (expressed in carbon dioxide equivalents) produced by an individual, event, organization, or product.
• Carbon Pricing: A financial strategy to capture the external costs of carbon emissions—such as damage to crops or health care costs—and tie them to their sources via a price on carbon emitted.
• Carbon Tax: A type of carbon pricing where the government sets a price per ton of carbon emitted.
  • Fee-and-Dividend Approach: Carbon tax proceeds are returned to citizens as a regular dividend to offset increased energy costs.
  • Revenue-Neutral Carbon Tax: A tax where the government returns all revenue to the public through dividends or tax cuts elsewhere, meaning the government does not keep the money.
• Cap-and-Trade: A market-based system where the government sets an overall limit (cap) on emissions. Companies are issued permits to pollute; those that emit less can sell their excess permits to those that emit more.
• Kyoto Protocol: An international treaty (adopted in 1997) that mandated developed nations to reduce greenhouse gas emissions. The U.S. did not ratify it.
• Carbon Neutrality: Achieving a state in which net greenhouse gas emissions are zero, usually by balancing emissions with removal or through carbon offsets.
• Carbon Offsets: Voluntary payments intended to enable another entity to help reduce emissions that one is unable to reduce oneself (e.g., paying to plant trees to offset flight emissions).
• Geoengineering: Large-scale, intentional interventions in the Earth’s natural systems to counteract climate change (e.g., reflecting sunlight with stratospheric aerosols or large-scale carbon capture).
• Thermohaline Circulation: A worldwide system of ocean currents driven by differences in temperature and salinity, which regulates global climate by transporting heat from the tropics to the poles.

Fundamental Factors of Climate

• Global Climate Change vs. Global Warming: "Global warming" refers specifically to the increase in Earth's average surface temperature. "Global climate change" is a broader term encompassing warming and all other changes, including precipitation shifts and storm frequency changes.
• Climate vs. Weather: Weather refers to short-term atmospheric conditions (minutes to days), while climate refers to the average of these conditions over a long period (typically 30 years or more).
• Three Main Factors Influencing Earth's Climate:
  1. The Sun: Provides light and heat energy.
  2. The Atmosphere: Insulates the planet and regulates temperature through the greenhouse effect.
  3. The Oceans: Store and transport heat and moisture.

Greenhouse Gases and Their Origins

• Common GHGs and Source Growth: Since 1750 (the start of the Industrial Revolution), GHG concentrations have spiked dramatically.
  • Carbon Dioxide ($CO_2$): Primary source is the combustion of fossil fuels (coal, oil, gas) and deforestation.
  • Methane ($CH_4$): From livestock enteric fermentation, landfills, and leaks from natural gas extraction.
  • Nitrous Oxide ($N_2O$): Primarily from agricultural soil management (synthetic fertilizers) and chemical manufacturing.
• Cooling Factors: Earth's climate can be cooled by aerosols (like volcanic ash or sulfate aerosols from coal combustion) which reflect solar radiation back into space, and increases in surface albedo (reflectivity), such as snow and ice cover.

Historical Trends and Observations

• Ice Cores: Data from ice cores spanning the last 800,000 years show a direct correlation between temperature and the concentrations of $CO_2$ and $CH_4$. When gas levels rise, temperatures rise.
• Temperature Increases: Average surface temperature has increased by about $1.1^{\circ}\text{C}$ ($2.0^{\circ}\text{F}$) over the past 100 years. Regions like Grand Junction and the high-altitude Western U.S. are warming faster than the global and U.S. averages due to lower humidity and faster snowpack loss.
• IPCC Predictions: The IPCC predicts surface temperatures will rise by $1.5^{\circ}\text{C}$ to $4.5^{\circ}\text{C}$ by the end of the 21st century (year 2100), depending on future emission levels.

Impacts of Climate Change

• Precipitation: Global precipitation is generally increasing because warmer air holds more water vapor. However, it is becoming more polarized: wet areas are getting wetter, and dry areas are experiencing more severe droughts.
• Extreme Weather: Examples include more frequent/intense hurricanes, droughts, heatwaves, and heavy downpours. These are linked to increased atmospheric energy and a weakened jet stream (Arctic amplification).
• Melting Snow and Ice: Shrinking glaciers and ice caps reduce freshwater supplies, lower surface albedo (leading to more warming), and contribute to sea level rise.
• Sea Level Rise: Two main causes are thermal expansion (water expands as it warms) and melting of terrestrial ice (glaciers and ice sheets). Effects include coastal flooding, salt-water intrusion into aquifers, and loss of coastal habitats. The IPCC predicts a rise of $0.26$ to $0.82\,m$ by 2100.
• Ocean Acidification: Oceans absorb about 25-30% of anthropogenic $CO_2$. The resulting acidity kills coral reefs (bleaching) and dissolves the shells of mollusks and plankton, disrupting the food web.
• Human Impacts:
  • Health: Increased heat-related deaths, expansion of tropical diseases (e.g., malaria, West Nile), and respiratory issues from smog/wildfire smoke.
  • Wealth: Economic losses from agricultural failure, property damage from storms, and decreased labor productivity.
  • Security: Resource scarcity (water/food) leading to civil unrest and mass migrations/refugees.
• Plant Growth: Climate change may increase growth in some areas due to longer growing seasons and the fertilization effect of higher $CO_2$. However, this is countered by increased drought frequency, heat stress, and the spread of invasive pests/diseases.

Policy and National Response

• Skepticism: Resistance to climate science often stems from economic interests (fossil fuel industry), political ideology, or a lack of understanding of the difference between weather and climate.
• International Agreements:
  • Kyoto Protocol: Required developed nations to reduce emissions. The U.S. signed but never ratified it. It had limited success globally.
  • Paris Accord: A 2015 agreement where nearly all nations committed to keeping warming below $2^{\circ}\text{C}$. The U.S. withdrew under the Trump administration but rejoined under the Biden administration.
• Economic Impact: Most economic studies suggest that transitioning to a green economy creates more jobs in renewables and energy efficiency than it loses in fossil fuels, and preventing climate damage is cheaper than ignoring it.
• Local Action: Despite federal gridlock, many individual states (e.g., California), cities, and major corporations have set their own ambitious carbon-neutral goals.

Chapter 15: Nonrenewable Energy

Key Terminology and Definitions

• Non-renewable: Energy sources that exist in limited supply and cannot be replenished on a human timescale (e.g., fossil fuels, nuclear).
• Hydraulic Fracturing (Fracking): A technique for extracting natural gas or oil from shale rock by pumping high-pressure water, sand, and chemicals underground to crack the rock.
• Fossil Fuels: Highly combustible substances formed from the remains of organisms from past geologic ages (Coal, Oil, Natural Gas).
• Net Energy: The difference between the energy returned by a process and the energy invested in that process ($\text{Net Energy} = \text{Energy Returned} - \text{Energy Invested}$).
• EROI (Energy Returned on Investment): The ratio of energy produced to the energy required to produce it ($\text{EROI} = \frac{\text{Energy Returned}}{\text{Energy Invested}}$). Higher ratios are more efficient.
• Crude Oil/Petroleum: A liquid fossil fuel consisting of a mix of hydrocarbons, occurring naturally in underground deposits.
• Unconventional Fossil Fuels: Resources that are harder to extract, including Oil Sands (Tar Sands), Oil Shale, and Methane Hydrates (ice-like lattices of methane found in the Arctic or seafloor).
• Proven Recoverable Reserve: The amount of a fossil fuel that is technologically and economically feasible to remove under current conditions.
• Refining: The process of separating crude oil into various components (gasoline, diesel, asphalt) based on their boiling points.
• Reserves-to-Production Ratio (R/P ratio): The total remaining reserves divided by the annual rate of production. This estimates how many years a resource will last.
• Peak Oil: The point in time when the global production of oil reaches its maximum rate, after which production will decline.
• Mountaintop Removal Mining: A coal mining technique where the top of a mountain is blasted off to reach coal seams below.
• Directional Drilling: Drilling a well that deviates from vertical to reach resources under sensitive areas or to increase surface area in a reservoir.
• Clean Coal Technologies: Techniques like scrubbers and chemically treating coal to reduce sulfur and particulate emissions, though they do not eliminate $CO_2$.
• Carbon Capture and Storage (CCS): Capturing $CO_2$ emissions from power plants and pumping them underground into stable geologic formations.
• External Costs: Costs of energy production not reflected in the price, such as medical costs for asthma caused by pollution.
• Energy Efficiency: Obtaining a certain level of output while using less energy (a technological improvement).
• Energy Conservation: Reducing energy use through behavior changes (e.g., turning off lights).
• Energy Intensity: The energy use per unit of Gross Domestic Product (GDP). A lower intensity indicates more economic output per unit of energy.
• Cogeneration: A system where excess heat produced during electricity generation is captured and used to heat buildings.
• Rebound Effect: The phenomenon where gains in efficiency are offset by increased use of the device or service because it is now cheaper.
• Nuclear Fission: The splitting of an atomic nucleus (usually Uranium-$235$) which releases a massive amount of energy used to generate steam for electricity.

Fossil Fuel Overview

• Top 4 Non-renewable Sources (by usage): Oil, Coal, Natural Gas, Nuclear.
• US Energy Context: The U.S. contains 4% of the world's population but consumes 18% of global energy.
• Global Leaders:
  • Oil: Largest reserves in Venezuela/Saudi Arabia; Top producer is USA; Top consumer is USA.
  • Coal: Largest reserves in USA; Top producer is China; Top consumer is China.
  • Natural Gas: Largest reserves in Russia; Top producer is USA; Top consumer is USA.
• Formation and Abundance: Fossil fuels form from organic matter compressed under heat and pressure over millions of years. Coal is the most abundant fossil fuel.
• Unconventional Types: Oil sands, oil shale, and methane hydrates. Drawbacks include very low EROI, high water usage, and severe land disruption.
• Fuel Uses:
  • Coal: Primarily for electricity generation.
  • Natural Gas: Electricity, home heating, and industrial processes. (Advantage over coal: emits 50% less $CO_2$ per unit of energy produced).
  • Oil: Primarily transportation and plastics.
  • Oil-derived products: Gasoline, diesel, jet fuel, plastics, synthetic fibers (polyester), asphalt, lubricants.

Supply and Extraction

• Lifespan: At current rates, Oil and Natural Gas may last ~50 years; Coal may last ~200 years.
• Fracking: Expands oil/gas supply but risks groundwater contamination, air pollution, and induced seismicity (earthquakes).
• Deepwater Horizon: A 2010 offshore oil platform explosion in the Gulf of Mexico that caused the largest marine oil spill in history, devastating marine life and local economies.
• Keystone Pipeline: Proponents argue for energy security and jobs; opponents argue it risks spills and encourages carbon-intensive oil sand extraction.

Nuclear Power

• Mechanism: Uses Uranium-235 ($^{235}U$) in a fission chain reaction controlled by control rods.
• Top Producer: The United States produces the most nuclear power.
• Pros vs. Cons: Compared to coal, nuclear produces no air pollution or GHGs during operation. However, it requires huge capital investment, generates radioactive waste, and carries the risk of catastrophic meltdowns.
• Major Accidents:
  • Three Mile Island (US): Partial meltdown; minimal radiation release.
  • Chernobyl (Ukraine): Massive explosion and meltdown; widespread radiation and deaths.
  • Fukushima Daiichi (Japan): Tsunami-induced meltdown; large radiation release and evacuation.
• Waste Disposal: Currently stored on-site at power plants. Long-term solutions like Yucca Mountain have faced political and safety gridlock.

Chapter 16: Renewable Energy Alternatives

Key Terminology and Definitions

• Green-collar Jobs: Employment in the environmental sectors of the economy, particularly in renewable energy and energy efficiency.
• Passive Solar: Designing buildings to maximize direct sunlight absorption in winter and minimize it in summer (e.g., south-facing windows).
• Active Solar: Using technology to collect and distribute solar energy (e.g., flat plate collectors for water heating).
• Concentrated Solar Power (CSP): Using mirrors to focus sunlight onto a central receiver to generate heat for steam turbines.
• Photovoltaic (PV) Cells: Devices that convert sunlight directly into electricity using the photoelectric effect.
• Thin-film Solar Cells: PV materials compressed into ultra-thin sheets; less efficient but more versatile and cheaper.
• Net Metering: A policy where homeowners with solar panels can sell excess electricity back to the utility grid.
• Wind Turbines: Mechanical assemblies that convert the kinetic energy of wind into electrical energy.
• Geothermal Energy: Thermal energy generated from the Earth’s interior (magma, hot water, steam).
• Ground Source Heat Pumps (GSHPs): Systems that transfer heat between the ground and a building to provide heating/cooling, taking advantage of stable underground temps.
• Enhanced Geothermal Systems (EGS): Drilled holes where water is pumped into hot, dry rock to create steam where no natural water source exists.
• Ocean Energy: Includes Tidal Energy (tides), Wave Energy (surface waves), and Ocean Thermal Energy Conversion (OTEC) (temperature gradients).
• Hydropower: Using the energy of moving water to turn turbines. Types include Impoundment (dams), Run-of-river, and Pumped Storage.
• Bioenergy: Energy obtained from biomass (biological material from living or recently living organisms).
• Biofuels: Liquid fuels produced from biomass, such as Ethanol (from corn/sugar) and Biodiesel (from vegetable oils).
• Cellulosic Ethanol: Ethanol produced from the non-edible parts of plants (e.g., switchgrass, corn stalks); higher EROI than corn ethanol.
• Fuel Cells: Devices that use a chemical reaction involving hydrogen and oxygen to produce electricity, with water as the only byproduct.
• Electrolysis: The process of using electricity to split water ($H_2O$) into hydrogen and oxygen gases.

Renewable Energy Trends

• US Consumption: Approximately 12-13% of U.S. energy comes from renewables.
• Order (Most to Least Used): Bioenergy and Hydropower are historically highest, followed by Wind and Solar.
• Electricity: Wind and Hydropower provide the most renewable electricity.
• Economics: Renewables are becoming cheaper than fossil fuels. Wind and Utility-scale Solar are currently the cheapest sources of new electricity generation.

Specific Source Details

• Solar:
  • Harnessing: PV cells, CSP, passive design.
  • Benefit: No emissions, quiet, scalable.
  • Drawback: Intermittent (sun doesn't shine at night), high upfront cost.
• Wind:
  • Harnessing: Wind turbines.
  • Benefit: High EROI ($20:1$ or more), no emissions, multifuntional land use.
  • Drawback: Threat to birds/bats, intermittent, "NIMBY" (Not In My Backyard) opposition.
• Geothermal:
  • Harnessing: Tapping steam or hot water from underground.
  • Benefit: Baseload power (runs 24/7), very low emissions.
  • Drawback: Site-specific, can be exhausted if water is not reinjected.
• Hydropower:
  • Benefit: No emissions, very high EROI, adjustable output.
  • Drawback: Damming rivers destroys habitats, displaces people, and floods lands. It is not expanding because most suitable large rivers are already dammed.
• Bioenergy:
  • Usage: Heat (wood), electricity (biopower), transport (biofuels).
  • Developing vs. Developed: Developing nations use it for basic heating/cooking (wood/dung); developed nations use it for large-scale power and transport.
  • Sustainability: Corn ethanol is criticized for its low EROI (approx $1.3:1$) and for driving up food prices and fertilizer use.

Hydrogen Fuel Cells

• Function: Combines hydrogen and oxygen to produce electricity ($2H_2 + O_2 \rightarrow 2H_2O + \text{energy}$).
• Benefits: Zero vehicle emissions, high efficiency, can store renewable energy.
• Pollution Factors: The environmental impact depends on how the hydrogen is produced. If produced via electrolysis using wind power, it is "green." If produced from natural gas (methane), it still releases $CO_2$.