Sun-Earth System
Value Systems of Nature
- Supplement
Understanding Environmental Issues
- Supplement
Risk & Uncertainty

- Supplemental Information for the Environmental Educator -


  1. Provide a course introduction.
  2. Facilitate critical thinking about environmental issues.
  3. Provide awareness of the difficulty in defining the environment, environmental problems, and criteria for evaluating and ranking environmental problems.
  4. Provide the educator with information about the students' general understanding of environmental issues.


There are no right answers and the students responses will vary based on their experience and educational background. Answers should be graded based on a demonstration of critical thinking and the establishment of well-reasoned arguments for each question.


Class Discussion
The following is a list of ideas you may want to keep in mind when discussing the assignment.

1. Many students define "environmental problem" as "imbalances in the environment caused by humans." It may be helpful to point out that environmental problems can be natural or human caused and that they are typically defined as causing adverse effects.

2. Many students list environmental problems that overlap. For example, a student may list "Increased UV Exposure" and "Ozone Depletion" as two environmental problems.

3. There are no right answers. Experts in environmental ranking do not agree on which criteria should be used to prioritize environmental problems. Furthermore, priorities will vary among any group of people. For example:

  • Those working in different fields within EPA (air, water, land) will tend to place higher priority on their area of expertise.
  • Someone living in Los Angeles will have different priorities than someone living in Alaska.

4. There is often confusion about deriving the 100-point scale in question 8. It might be useful to illustrate an example of a student's answer or an example from the literature.


5. Ask some of the students with well-reasoned answers for each question to read their answers in class.

6. Histograms outlining the students answers for the following:

  • Criteria listed in question 7.
  • Highest ranked criterion for question 7.
  • Environmental problems listed in question 8.
  • Highest ranked environmental problem for question 8. See Figure One.

Figure 1: Highest ranked environmental problem

7. Discuss how definitions of certain criteria varied on the assignment.

  • For example, many students may list "Scale" as one of the criteria in question 7. A wide variety of definitions have been seen for this criterion: Number of people affected, geographical area, global vs. local, number of living organisms affected, etc.

8. A comparison of perceptions of environmental risk.

  • Compare the environmental problems listed in question 8 to the U.S. EPA Ranking.
  • Compare the public perception of environmental risks to the U.S. EPA Ranking

    Reference: Unfinished Business, 1987

9. Point out that the mayor of your city will most likely focus on more local issues than the President of the United States.

Summary of Student Answers:

Go to Understanding Environmental Issues Assignment

  ©Copyright 2003 Carnegie Mellon University
This material is based upon work supported by the National Science Foundation under Grant Number 9653194. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors and do not necessarily reflect the views of the National Science Foundation.