Environmental Science: Climate Change, Energy Resources, and Waste Management

Comprehensive practice flashcards reviewing climate change fundamentals, fossil fuels, nuclear energy, renewable power systems, and solid and hazardous waste management.

How does weather differ from climate?

Weather refers to the short-term conditions in the atmosphere at a given place and time (such as temperature, atmospheric pressure, precipitation, cloudiness, humidity, and wind) which can vary hour to hour and day to day. Climate refers to the long-term weather patterns prevailing over a given area of the planet over hundreds or thousands of years.

From what Greek words is the term 'climate' derived, and what did they historically denote?

It is derived from the Greek word klinein (meaning 'to slope'), which evolved into klima, connoting a zone or region of the Earth characterized by its atmospheric conditions.

What are the two most important factors that define an area's overall climate?

Temperature and precipitation.

What percentage of incoming solar energy is absorbed to run biogeochemical cycles, and what percentage is reflected back into space?

$69\%$ is absorbed to run the hydrologic, carbon, and other biogeochemical cycles, while the remaining $31\%$ is reflected away by clouds, snow, ice, and the ocean.

On average, how much solar energy enters Earth's atmosphere, and how much reaches Earth's surface?

About $1366\,\text{W/m}^2$ enters Earth's atmosphere, resulting in about $1000\,\text{W/m}^2$ reaching Earth's surface.

Why does sunlight hitting the equator result in higher solar intensity than sunlight hitting the poles?

Sunlight hitting the equator strikes vertically and is concentrated on a small surface area, whereas light striking toward the poles hits at an angle and covers a much larger surface area.

What is the angle of Earth's axial tilt relative to a line perpendicular to its orbital plane, and what phenomenon does it determine?

The tilt is $23.5^\circ$, and it determines the Earth's seasons.

What is the difference between aphelion and perihelion?

Aphelion is the point in Earth's orbit farthest from the Sun, whereas perihelion is the point in Earth's orbit closest to the Sun.

What astronomical events are defined as an equinox and a solstice?

An equinox occurs when the noon Sun is directly over the equator, causing nearly equal day and night lengths. A solstice occurs when the noon Sun is directly above the Tropic of Cancer or Tropic of Capricorn, marking the longest period of daylight (summer solstice) or shortest period of daylight (winter solstice).

What three orbital variations make up the Milankovitch cycles, and what are their approximate periodicities?

1. Eccentricity (changes in the shape of Earth's orbit): approximately $100{,}000\,\text{years}$.
2. Obliquity/Tilt (changes in axial tilt between $22.1^\circ$ and $24.5^\circ$): approximately $41{,}000\,\text{years}$.
3. Precession (wobble in Earth's rotational axis): approximately $23{,}000\,\text{years}$.

How does a rain shadow form on the leeward side of a mountain range?

Prevailing winds push warm, moist air up the windward side of a mountain, where it cools and condenses to release precipitation; dry air then descends on the far (leeward) side, creating an arid or semiarid region.

What caused the temporary dip in global temperatures recorded in the early 1990s?

The eruption of Mount Pinatubo in 1991.

By how much does the Intergovernmental Panel on Climate Change (IPCC) predict global temperatures will increase by the year 2100?

Between $2.0^\circ\text{C}$ and $5.5^\circ\text{C}$ ($3.6^\circ\text{F}$ to $9.9^\circ\text{F}$).

How much has atmospheric carbon dioxide ($CO_2$) concentration increased between pre-industrial times (200 years ago) and 2015?

It increased from $288\,\text{ppm}$ to $401\,\text{ppm}$.

How do greenhouse gases and aerosols differ in their impact on radiative forcing and atmospheric lifespan?

Greenhouse gases cause positive radiative forcing (atmospheric warming) and can remain in the atmosphere for hundreds of years. Aerosols generally cause negative radiative forcing (cooling) and remain in the atmosphere for only days to months.

According to the Second National Communication to the UNFCCC, what are the percentage contributions of greenhouse gas emissions by sector in the Philippines?

Energy: $55\%$, Agriculture: $29\%$, Waste: $9\%$, and Industrial Process: $7\%$.

How much did global sea level rise during the 20th century, and how much is it estimated to rise further by 2100?

Sea levels rose $10\,\text{cm}$ to $20\,\text{cm}$ ($4\,\text{in}$ to $8\,\text{in}$) in the 20th century, and are estimated to rise an additional $20\,\text{cm}$ to $50\,\text{cm}$ ($7.9\,\text{in}$ to $20\,\text{in}$) by 2100.

What is coral bleaching and what environmental trigger causes it?

Coral bleaching is the process where corals expel the symbiotic algae (zooxanthellae) living inside their tissues due to excessively warm water temperatures, turning the corals completely white.

What are the major steps in the Vattenhall carbon capture and storage pilot project illustrated in the diagram?

1. Coal is burned in a gasifier.
2. Particulates, sulfur, and other contaminants are removed.
3. $CO_2$ is absorbed and desorbed.
4. Hot, $CO_2$-free gas generates electricity in a gas turbine.
5. Remaining heat is captured in a heat recovery steam generator.
6. The separated $CO_2$ is piped away for underground storage.

What was the purpose and adoption date of the Montreal Protocol?

Finalized in 1987 in Montreal, Canada, it is a global agreement designed to protect the stratospheric ozone layer by phasing out the production and consumption of ozone-depleting substances (ODS), such as chlorofluorocarbons (CFCs) and halons.

What is the central temperature goal established under the 2015 Paris Climate Agreement?

To keep the global average temperature increase below $1.5^\circ\text{C}$.

How do primary energy sources differ from secondary energy sources?

Primary energy sources are those found or stored directly in nature (such as coal, oil, natural gas, biomass, potential, or solar energy). Secondary energy sources must be produced by converting primary sources (such as electricity and steam).

Which country had the highest per capita commercial energy consumption in 2012 among Canada, the United States, Sweden, Mexico, India, and Nigeria?

Canada, with an energy consumption exceeding $400\,\text{gigajoules}$ per person.

What are the two basic types of coal mining, and what proportion of U.S. coal does each supply?

Surface mining (extracting coal within $30\,\text{m}$ of the surface) supplies $60\%$ of U.S. coal, and subsurface mining (deep underground extraction) supplies approximately $40\%$.

What is acid mine drainage and what dangerous substances does it leach?

It is sulfuric acid and toxic dissolved minerals (such as lead, arsenic, and cadmium) that wash from coal and metal mines and mine waste into nearby water bodies.

How does fluidized-bed combustion reduce pollutants during coal combustion?

Crushed coal is mixed with limestone to neutralize acidic compounds, which removes sulfur, produces fewer nitrogen oxides, and generates more heat per unit of coal.

What device is shown in this diagram, and what chemical mechanism does it use to clean exhaust gas?

It is a wet scrubber spray tower, which uses a limestone slurry to react with sulfur dioxide and acidic emissions in fuel gas, precipitating out gypsum and releasing clean gas.

What is the primary chemical constituent of natural gas, and what defines wet vs. dry natural gas?

Natural gas mainly consists of methane ($CH_4$). Wet natural gas contains other hydrocarbons (ethane, propane, butane) in addition to methane, whereas dry natural gas has had these other hydrocarbons removed.

What were the environmental damages caused by the 1989 Exxon Valdez supertanker oil spill in Prince William Sound, Alaska?

$260{,}000\,\text{barrels}$ ($10.9\,\text{million gallons}$) of crude oil spilled, killing approximately $300{,}000\,\text{birds}$ and $3500$ to $5500\,\text{sea otters}$, declining orca and harbor seal populations, disrupting salmon migration, and halting commercial fishing.

How does the fuel quantity required to power a city of 1,000,000 people compare between a coal plant and a nuclear plant?

A coal-burning power plant requires $2{,}000{,}000\,\text{kg}$ of fuel per day, while a nuclear power plant requires only $50\,\text{kg}$ of fuel per day.

What is uranium enrichment, and to what concentration must uranium-235 ($^{235}\text{U}$) be concentrated for use in conventional nuclear reactors?

Enrichment is the refining process that increases the concentration of fissionable $^{235}\text{U}$ from its natural abundance ($0.72\%$\text{ in raw ore}) to approximately $3\%$.

What are the four basic components of a pressurized water nuclear reactor?

The reactor core (where fission takes place), the steam generator (where core heat produces steam), the turbine (which uses steam to turn an electrical generator), and the condenser (which cools steam back into liquid water).

What occurred during the three major historical nuclear power plant accidents: Three Mile Island, Chernobyl, and Fukushima Daiichi?

Three Mile Island (1979, USA) had a partial meltdown, but containment largely held without significant radiation release. Chernobyl (1986, Ukraine) suffered explosions that ripped apart the reactor, releasing vast radioactive fallout and forcing $170{,}000\,\text{people}$ to permanently evacuate. Fukushima Daiichi (2011, Japan) lost cooling power after a $9.0\,\text{magnitude}$ earthquake and tsunami, leading to meltdowns in three reactors and hydrogen explosions.

What is the Bataan Nuclear Power Plant, and what is its operational status?

It is a $621\,\text{MW}$ power plant constructed in August 1977 as the Philippines' first and only attempt at nuclear power development; it was placed on 'preservation mode' and was never operated.

How does active solar heating differ from passive solar heating?

Active solar heating uses mechanical devices like pumps and fans to circulate solar-heated fluids from collectors to storage tanks or living spaces. Passive solar heating relies on architectural designs (such as south-facing windows, roof overhangs, and thick thermal mass walls) to collect, store, and distribute heat naturally by convection without mechanical assistance.

Who discovered the photovoltaic effect, and in what year?

French physicist Edmond Becquerel in 1839.

How does the concentrated solar power plant shown in the diagram generate and store electricity using molten salt?

Tracking mirrors (heliostats) concentrate sunlight onto a central tower receiver. Liquid cold salt at $288^\circ\text{C}$ is pumped through the receiver, heated to $566^\circ\text{C}$, and stored in a hot salt tank; hot salt is then routed through a steam generator to drive a steam turbine and generate electricity on demand.

How does a hydrogen fuel cell generate electrical power?

Hydrogen enters at the anode where atoms are stripped of electrons; the electrons flow through an external circuit to create electricity, while the positive protons pass through a membrane to the cathode, combining with oxygen and returning electrons to produce water and heat.

What feedstocks distinguish the four successive generations of biofuels shown in the diagram?

1st Generation: Food crops (sugar cane, palm oil, rapeseed). 2nd Generation: Lignocellulosic non-food biomass (wood, straw, agricultural waste). 3rd Generation: Marine organisms (macroalgae/seaweed, microalgae). 4th Generation: Breakthrough technology (solar-to-fuel, advanced algae, and engineered carbon-negative crops).

How much carbon dioxide emission is avoided for every kilowatt-hour ($\text{kWh}$) of electricity generated by wind power instead of fossil fuels?

Every $\text{kWh}$ of wind electricity prevents the release of $2.2\,\text{lb}$ of $CO_2$.

What is the energy conversion efficiency of hydropower, and what percentage of global electricity does it supply?

Hydropower converts $90\%$ of water's potential energy into electricity (the most efficient energy source) and generates about $19\%$ of the world's electricity.

What are the names of major operating geothermal and hydroelectric plants in the Philippines referenced in the lectures?

Geothermal plants include MakBan (Calauan, Laguna), Palinpinon (Negros Oriental), and Maibarara (Batangas). Hydroelectric facilities include Maria Cristina Falls (Lanao del Norte), SOLECO (Southern Leyte), and San Roque Power Corporation (Pangasinan).

What is the distinction between energy conservation and energy efficiency?

Energy conservation means using less energy by reducing consumption and cutting waste (e.g., turning off unused appliances). Energy efficiency means using less energy to accomplish the same amount of work through improved technology (e.g., replacing incandescent bulbs with CFLs).

What are the fiscal and non-fiscal incentives established by the Renewable Energy Act of 2008 (Republic Act No. 9513) in the Philippines?

Fiscal incentives include Income Tax Holiday, low income tax rate, duty-free importation and VAT zero-rating, reduced government share, tax credits on domestic capital equipment, cash incentives for missionary electrification, universal charge exemptions, and carbon credit tax exemptions. Non-fiscal incentives include the Renewable Portfolio Standards (RPS), Feed-in Tariff (FIT) System, Net-Metering, and the Green Energy Option.

What is Municipal Solid Waste (MSW), and what fraction of total solid waste does it represent?

MSW is combined solid waste produced by homes and commercial workplaces other than factories (trash or garbage); it makes up less than $2\%$ of total solid waste.

According to official data for 2008–2013, what are the percentage contributions of the main municipal solid waste categories in the Philippines?

Biodegradables comprise $52.31\%$, Recyclables comprise $27.78\%$ (plastics $10.55\%$, paper/cardboard $8.70\%$), Residual waste comprises $17.98\%$, and Special waste comprises $1.93\%$.

What are dioxins, and what makes them hazardous persistent organic pollutants (POPs)?

Dioxins are a group of 75 chemically related chlorine-containing compounds produced primarily from the combustion and incineration of medical and municipal wastes; they bioaccumulate in body fat, cause multiple cancers in lab animals, and disrupt reproductive, immune, and nervous systems.

What design features are incorporated into a modern sanitary landfill to protect local water sources from leachate?

A double-liner system at the base consisting of alternating layers of compacted clay and plastic (plastic, clay, plastic, clay), paired with a drainage network that collects and treats leachate (liquid seeping through the refuse).

What Philippine law banned municipal solid waste incineration, and when did the phase-out take effect?

Republic Act No. 8749 (The Clean Air Act of 1999), which required the phase-out of waste incinerators by July 2003.

What are the six functional elements of a solid waste management system?

1. Generation
2. Storage
3. Collection
4. Transportation
5. Processing and Recovery
6. Disposal

What is the waste management hierarchy established by the U.S. Pollution Prevention Act of 1990?

From most preferred to least preferred: Source reduction / prevention at the source, followed by recycling, then burning for energy recovery, treatment, and lastly disposal in landfills.

What is Republic Act No. 9003 in the Philippines, and what is its primary mandate?

The Ecological Solid Waste Management Act of 2000 (signed January 26, 2001), which mandates systematic waste management emphasizing segregation at source, waste avoidance, reduction, reuse, and recycling.

What exact environmental resources are conserved by recycling 1 ton of paper according to the lecture text?

17 trees, 7000 gallons of water, $4100\,\text{kWh}$ of energy, and 3 cubic yards of landfill space.

How do primary (closed-loop) recycling and secondary recycling differ?

In primary (closed-loop) recycling, waste materials are recycled into new products of the exact same type (such as aluminum beverage cans remade into new cans). In secondary recycling, waste materials are converted into completely different products (such as shredded tires converted into rubberized asphalt).

What is bioremediation and phytoremediation in toxic waste treatment?

Bioremediation uses bacteria and enzymes to break down and detoxify hazardous organic substances. Phytoremediation uses natural or genetically engineered plants ('pollution sponges') to absorb, filter, and extract contaminants from polluted soil and water.

How does a plasma gasifier process hazardous organic waste, as illustrated in the schematic?

It uses an electric arc plasma torch to generate extreme heat, decomposing liquid or solid hazardous organic waste into elemental ions and atoms that exit as cleanable synthetic gas, while non-combustible inorganic components melt into an inert slag or molten metal quench.

What is the primary objective of Republic Act No. 6969 in the Philippines?

Known as the Toxic Substances and Hazardous and Nuclear Wastes Control Act of 1990, it regulates, restricts, or prohibits the importation, manufacture, processing, sale, distribution, use, and disposal of chemical substances and hazardous/nuclear wastes that present risk to human health or the environment.