Introduction to Environmental Science

Earth seen from Apollo 17 Although the environment is complex and environmental issues seem to cover an unmanageable number of topics, the science of the environment can be implicitly summarized with three fields of study: the human population, urbanization, and sustainability within a global perspective. Naturally, these topics are integrated with the decisions that people make about nature. However, the solutions depend on various levels of compromise between science and nature.

Viewed from space, our planet Earth resembles a small blue marble. As we interact with others and travel from place to place, the size of our planet seems voluminous. However, if you ask an astronaut, she would tell you that Earth and its systems are finite and limited. As our population expands, technological powers expand and consumption of resources increases so does our capacity to alter our planet and damage the systems that maintain our lives.

Earth is the only planet in the Solar System that sustains life. Life on Earth is critically dependent on the abundance of water (liquid, vapor, and ice). Carbon and the multitude of its compounds is the very basis of life and its greatest reservoir. In the atmosphere, carbon is fully oxidized as carbon dioxide, fully reduced as methane, and in particulate form as black carbon, soot produces the greenhouse effect making Earth habitable. Earth's atmosphere and electromagnetic field protect the planet from harmful radiation while allowing useful radiation to reach the surface and sustain life. Earth exists within the Sun's zone of habitation, and with the moon, maintains the precise orbital inclination needed to produce our seasons.

Essential Questions

Why is it important to identify key environmental problems?
How do the decisions that we make in our day-to-day lives affect the environment?
How do ethics, economics, and politics factor in environmental science principles?
What is the best way to achieve sustainability?

Key Terms

Primary Air Pollutants: produced by humans & nature (CO, CO 2, SO 2, NO, hydrocarbons, particulates).

Particulate Matter: sources include burning fossil fuels and car exhaust. Effects include reduced visibility, respiratory irritation. Methods of reduction include filtering, electrostatic precipitators, alternative energy).

Ozone: Secondary pollutant, NO 2 + UV 1 NO + O; O + O 2 1 O 3 , with VOCs. O3 causes respiratory irritation and plant damage. Reduced by reducing NO emissions and VOCs.

Sulfur Oxides: (SO x ) Primary source is coal burning. Primary and secondary effects include acid deposition, respiratory irritation, plant damage. Reduction methods include scrubbers, burning low sulfur fuel.

Carbon Dioxide: (CO 2 ) Sources include the combustion of fossil fuels. Effects: greenhouse gas- contributes to global warming. Reduction is accomplished by increased fuel efficiency (gas mileage), mass transit (reduction).

Ozone Depletion: caused by CFCs, methyl chloroform, carbon tetrachloride, halon, methyl bromide all of which attack stratospheric ozone. Negative effects of ozone depletion include increased UV, skin cancer, cataracts, and decreased plant growth.

Greenhouse Gases: Most significant: H 2 O, CO 2, methane (CH 4 ), CFCs. Trap outgoing infrared energy (heat) causing Earth to warm.

Greenhouse Effect: a vital process, required for life to exist on Earth. If accelerated, bad leads to global warming.

Effects of Global Warming: rising sea level (due to thermal expansion not melting ice), extreme weather, droughts (famine), and extinctions.

Electricity Generation: steam, from water boiled by fossils fuels or nuclear energy, or falling water is used to turn a generator.

Petroleum (Crude Oil) Formation: microscopic aquatic organisms in sediments converted by heat & pressure into a mixture of hydrocarbons.

Petroleum Pros: cheap, easily transported, high-quality energy. Cons: reserves depleted soon, pollution during drilling, transport, and refining, land subsidence, burning oil produces CO 2.

Coal Formation: prehistoric plants buried un-decomposed in oxygen-depleted water of swamps/bogs converted by heat and pressure.

Ranks of Coal: peat, lignite, bituminous coal, anthracite coal.

PCBs (Polychlorinated Biphenyls): Stable, long-lived, carcinogenic chlorinated hydrocarbons. Produced by the electronics industry.

Multiple Use Public Lands: National Forest & National Resource lands.

Moderately Restricted Use Public Lands: National Wildlife Refuges

Restricted Use Public Lands: National Parks & National Wilderness Preservation System

Rachel Carson: published Silent Spring in 1962; documented the environmental damage done by DDT and other pesticides which heightened public awareness at the start of the modern environmental movement.

John Muir: founded Sierra Club in 1892; fought unsuccessfully to prevent the damming of the Hetch Hetchy Valley in Yosemite National Park.

Gifford Pinchot: first chief of the US Forest Service; advocated managing resources for multiple uses using principles of sustainable yield.

Aldo Leopold: wrote A Sand County Almanac published a year after his death in 1948; promoted a "Land Ethic" in which humans are ethically responsible for serving as the protectors of nature.

Sustainable development: the idea that economic improvement for the world's poorest populations is possible without devastating the environment

Ecological footprint: to measure the demands placed on nature by individuals and nations. A simple questionnaire of 16 items gives a rough estimate of your personal footprint.

Please review these key environmental science terms below.

RESOURCES IN THIS MODULE ARE OPEN EDUCATIONAL RESOURCES (OER) OR CREATED BY GAVS UNLESS OTHERWISE NOTED. SOME IMAGES USED UNDER SUBSCRIPTION.