Environmental Science: A Comprehensive Guide to Earth’s Systems

Environmental Science: An academic field offering an integrated, quantitative, and interdisciplinary approach to studying Earth’s components, their interactions, and their relationship with human systems to solve environmental problems.

Environment: The study of interactions between physical, chemical, biological, and social components of the natural world, including their effects on organisms and human impacts.

Multidisciplinary Field: Combines natural and social sciences.

Scientific Method: A planned, organized approach to problem-solving.

Systems Science: Considers interactions between Earth’s spheres—atmosphere, hydrosphere, cryosphere, geosphere, pedosphere, biosphere, and magnetosphere—and human societal impacts.

Analytic and Reductionistic: Employs analytical (measurement and interpretation) and reductionist (explanation through smaller entities) views of Earth’s spheres and subsystems.

Holistic and Global: Emphasizes the whole system rather than individual parts.

Anthropocene: The current geologic epoch significantly influenced by humans. The term combines “anthropo” (human) and “-cene” (epoch).

Natural Resource: Any material, service, or information from the environment valuable to society.

Environmental Impact: Potential adverse effects from development, industrial, or infrastructural projects, or substance release.

Environmental Hazard: A substance, state, or event threatening the environment or human health, including pollution and natural disasters.

Contamination: The presence of a substance where it shouldn’t be, or at concentrations above background levels.

Pollution: Introduction of contaminants into the natural environment causing adverse changes.

Pollutant: Waste material polluting air, water, or soil (liquids, solids, or gases).

Renewable Energy: Energy from a source not depleted when used.

Non-renewable Energy: Energy from a source depleted when used.


Petroleum: Formed from ancient animals and plants transformed by heat and pressure into crude oil. Pros: Economical production and easy transport. Cons: High CO2 emissions.

Propane: A byproduct of natural gas processing and crude oil refining. Pros: Nontoxic and insoluble in water. Cons: Highly flammable.

Natural Gas: Primarily methane, with ethane, butane, propane, carbon dioxide, nitrogen, helium, and hydrogen sulfide. Found underground through drilling. Pros: Widely available. Cons: Pipelines impact ecosystems.

Coal: Formed from ancient trees and plants transformed by heat and pressure into coal. Pros: Abundant supply. Cons: Acid rain.

Nuclear Energy: Generated in reactors where nuclear fuel fission heats water, producing steam to turn turbines and generate electricity. Pros: No greenhouse gases or CO2 emissions. Cons: Radioactive waste.

Solar Energy: Generated when photovoltaic cells convert sunlight into electricity. Pros: Non-polluting. Cons: Dependent on sunny weather.

Hydroelectric Energy: Generated when flowing water turns turbines to generate electricity. Pros: No emissions. Cons: More expensive than fossil fuel systems.

Wind Power: Generated when wind turns turbines to generate electricity, often stored in batteries. Pros: No emissions. Cons: Extensive land use.


  1. Abundant supply found in water: Hydrogen
  2. Generated by underground heat via steam wells: Geothermal Energy
  3. Less energy per gallon than gasoline/diesel: Ethanol
  4. Usable in diesel engines: Biomass
  5. Produced from vegetable oils, animal fats, recycled greases, and waste products: Biomass
  6. Found in few areas worldwide: Geothermal Energy
  7. Subset of biomass from plant/tree residue: Ethanol
  8. Easily manufactured with fewer emissions than fossil fuels: Biomass
  9. Storage/fuel cell technology still developing: Hydrogen
  10. Extensive cropland use: Ethanol

The Atmosphere: The gaseous envelope surrounding Earth, divided into layers.

Troposphere: Meteorological phenomena (clouds, fog, frost, dew, rain, snow, hail, hurricanes, whirlwinds, dust storms, tornadoes), and the greenhouse effect.

Stratosphere: The ozone layer (ozonosphere), and only horizontal air currents. Aircraft often fly here to avoid tropospheric turbulence.

Mesosphere: Noctilucent clouds (ice clouds), and chemicals absorbing solar energy.

Thermosphere: Polar auroras (Aurora borealis/australis), and the altitude where individuals are considered astronauts. Space shuttles and some satellites orbit here.

Ionosphere: Contains free ionic particles and reflects radio waves (long-distance communication).

Exosphere: The outermost layer with no definite outer limit. Many satellites orbit here.


  1. Problem of long-term waste storage: Nuclear
  2. Little ecosystem disruption: Wind Power
  3. More expensive than fossil fuel systems: Hydroelectric
  4. Systems last 15-30 years: Solar
  5. Extensive land use: Wind Power
  6. Currently uses a large amount of fossil fuels: Hydroelectric
  7. High initial investment: Solar
  8. Reliable: Hydroelectric
  9. Can pose a threat to birds: Wind Power
  10. Higher capital costs due to safety, emergency, containment, waste, and storage systems: Nuclear
  11. Requires large physical space: Solar
  12. Most abundant energy source available: Solar