Introducing Environmental Science and Sustainability

Chapter 1 Introducing Environmental Science and Sustainability

Lecture Outline:

• Human Impacts on the Environment
• Increasing human numbers
• Although several million species inhabit Earth, the human species is the most

significant agent of environmental change on the planet ii. Over 7.16 billion people currently inhabit planet Earth iii. Human activities, such as overpopulation, deforestation, pollution and species eradication are disrupting global systems

• The gap between rich and poor countries
• 81% of the world’s population live in poor countries

1. Poor countries fall into two subcategories: moderately developed

countries (Mexico, South Africa, Thailand) and less developed countries (LDCs - Bangladesh, Ethiopia, Laos)

• Nearly one in two people lives in extreme poverty which is associated

with low life expectancy, illiteracy, and inadequate access to health services, safe water, and balanced nutrition ii. Countries with complex industrialized bases, low rates of population growth, and high per capita incomes are considered highly developed countries (HDCs - Canada, Japan, the United States, and most of Europe) II. Population, Resources, and the Environment

• Types of resources
• Nonrenewable resources are present in limited supplies and are depleted by

use (aluminum, copper, fossil fuels) ii. Renewable resources are replaced by nature fairly rapidly and can be used forever as long as they are not overexploited in the short term (trees, animals, soils, fresh water)

• Resource consumption
• Consumption is the human use of materials

ii. A single child born in a HDC causes a greater impact on the environment and on resource depletion than 12 or more children born in a developing country

• People overpopulation and consumption overpopulation
• A country is overpopulated if the level of demand on its resource base results

in damage to the environment

ii. A country can be overpopulated in two ways: people overpopulation (LDCs)

and consumption overpopulation (HDCs) iii. The amount of productive land, fresh water, and ocean required on a continuous basis to supply a person food, wood, energy, water, housing, clothing, transportation, and waste disposal is termed an ecological footprint

• The IPAT model
• The IPAT model shows the mathematical relationship between environmental

impacts and the forces driving them: I = P x A x T

(Environment 9e Peter Raven, David Hassenzahl, Mary Catherine Hager, Nancy Gift, Linda Berg) (Solution Manual, For Complete File, Download link at the end of this File) 1 / 4

Chapter 1

ii. The three most important factors in determining environmental impact (I) are: number of people (P), the affluence per person (A), and the environmental effects of the technologies used to obtain and consume resources (T) III. Sustainability

• When the environment is used sustainably, humanity’s present needs are met without

endangering the welfare of future generations

• Inadequate understanding of how the environment works and how human choices

affect the environment is a major reason that problems of environmental sustainability are difficult to resolve

• Sustainability and the Tragedy of the Commons
• Proposed by Garrett Hardin in 1968, he postulates that our inability to solve

many environmental problems is the result of a struggle between short-term individual welfare and long-term environmental sustainability and societal welfare ii. Effective legal and economic policies are needed to prevent the short-term degradation of our global commons iii. The shared responsibility for the sustainable care of our planet is termed stewardship

• Global plans for sustainable development
• The goals of Agenda 21 are achieving improved living conditions for all

people while maintaining a healthy environment in which natural resources are not overused and excessive pollution is not generated

iii. Three factors interact to promote sustainable development: environmentally

sound decisions, economically viable decisions, and socially equitable decisions.IV. Environmental Science

• Environmental science encompasses the many interconnected issues involving human

population, Earth’s natural resources, and environmental pollution

• Earth systems and environmental science
• Understanding how systems that consist of many interacting parts function as

a whole help scientists gain valuable insights that are not obvious when looking at system components ii. Environmental scientists often use models to describe the interaction within and among environmental systems iii. Many aspects of Earth’s systems are in a steady state of dynamic equilibrium

• Feedback occurs when a change in one part of the system leads to a

change in another part

• A negative feedback mechanism works to keep an undisturbed system

in dynamic equilibrium, and occurs when a change in some condition triggers a response that counteracts, or reverses, the changed condition

• A positive feedback mechanism leads to greater change from the

original condition, and occurs when a change in some condition triggers a response that intensifies the changing condition

• Science as a process
• There is no absolute certainty or universal agreement about anything in

science; it is self-correcting over time 2 / 4

Chapter 1

ii. The established processes scientists use to answer questions or solve problems are collectively called the scientific method

1. The scientific method involves five steps: recognize a problem or

unanswered question, develop a hypothesis, design and perform an experiment to test the hypothesis, analyze and interpret the data to reach a conclusion, share new knowledge

• Scientists collect objective data by observation and experimentation
• Inductive reasoning is the basis of modern experimental

science

• Deductive reasoning is used to determine the type of

experiment or observations necessary to test a hypothesis

• Controls and variables are accounted for in experimental design
• Scientific theories are integrated explanations of numerous hypotheses,

each supported by a large body of observations and experiments and evaluated by the peer review process

• Addressing Environmental Problems
• There are five stages in addressing an environmental problem: scientific assessment,

risk analysis, public education and involvement, political action, evaluation

• The reversal of the pollution of Lake Washington is a clear example of how

environmental science identifies and addresses environmental problems (read and

discuss CASE IN POINT: Lake Washington) 3 / 4

Chapter 1

In-Class Activities:

Instructor Notes for In-Class Activity 1

Title: Student Resource Use and IPAT

Time: 10 minutes prep; 15 – 20 OR 40 – 50 minutes in class

Materials: Paper for class, or print instructions on worksheets. Post the instructions on a PowerPoint or overhead as an alternative to printing out instructions.Either provide paper for students or let them bring their own.

Handouts: Optional. See below.

Procedures: Divide class into at least five groups of two to four students. Assign each group of students to one of the five categories. Each group of students will try to estimate how much of one of five categories of resources a

typical student uses in a single day. The categories are:

• Agricultural
• Consumer goods
• Infrastructure
• Water
• Energy

Notes to instructor:

• Give the students the next following “challenge” after they have

spent some time working on their lists

• Keep in mind that there should be overlap in these lists. For

example, energy is needed to provide any of the other four categories; agriculture is the source of multiple types of resources, and so on.

• Use this lesson to emphasize that everything is either matter or

energy

• To shorten the exercise, omit the IPAT part, or assign as homework

Next, have them evaluate the “technology” component of each, in the context of IPAT. Does this by having them assume that world Population will stabilize at about twice the current size, and all of those people will seek Affluence like that found in highly developed countries. What types of technologies would be required to keep impacts constant? Is that even possible?

Student

Instructions:

• Estimate how much of the resource type assigned to you

(Agricultural, consumer goods, infrastructure, water and energy) a typical student uses in a day. Think broadly!

• Next, evaluate the “technology” component of your resource, in

the IPAT model. Assume that world Population will stabilize at about twice the current size, and all of those people will seek Affluence like that found in highly developed countries. What

• / 4