Chapter 1


What is Global Change?
"Exponential growth in human population, rapid technological advances, and significant increases in both material and energy consumption have put humans in a position where their daily activities are altering entire global systems such as the atmosphere and the oceans at a rate that has never before been experienced on this planet. It is the unprecedented rate of this change that is largely responsible for what we are calling global change." (Global Change and Canadians, p.2.)

Summary

Chapter 1 provides an introduction to the concept of global change and an overview of the changing Earth system, the special nature of the Earth's ecosystem, and a comparison of geological and human time scales. It also discusses some possible causes of global change, describes the global ecosystem, and provides some insight into current global change research.

Educational Significance

Global change is a complex and abstract concept. The challenge educators face is to make global change issues relevant and personal for students, to simplify the complexity of the issues, and to find ways to give students the opportunity to think critically about them.

Learning Outcomes

Students will:

  • provide an indication of prior knowledge;
  • understand the special and changing nature of the Earth's ecosystem;
  • understand our dependence on the Earth's ecosystem;
  • investigate the effect human activity has on global change;
  • understand the general causes of ecosystem degradation; and
  • begin to examine what we can do to alleviate environmental degradation.

Suggested Learning Activities

The following activities are presented as ideas for focusing study on the global change issues presented in the chapter. Whether you decide to develop one, or many of these activities, they should always be introduced by relating them to major themes contained within the chapter.

1.0 PERSONAL TIMELINE


Make a personal timeline. Start when you entered school, around 5 years of age and continue to the present year. Along the line, note important events in your life, such as the birth of a brother or sister, or the move to a new school. Think of changes you have seen in your life; new technology (fax, cellular phone, computer games), changes in your local environment (new housing developments, new roads, new construction downtown, traffic changes), political changes (Provincial and Federal elections, wars and other important world events). Discussion questions should explore the relationship between observed changes in the student's personal life and global change issues, for example
  • How many of these changes could have an impact on the global environment?
  • Do you have to do anything in your daily life because of global change?
  • Do you do things differently than before?

1.1 MENTAL GRAPHING

Make some "mental" graphs. Without using research tools, imagine what the graphs would look like for:
  • world population growth in developed and developing countries since 1750 (Global Change and Canadians, P.10)
  • your city's (or rural community's) population since 1945, by five year intervals
  • amount of farmland in your province since 1945
  • global population living in urban areas from 1955 and projected to 2025 (Global Change and Canadians, P.40)
  • demand for electrical power since 1945
  • total fish catch (Atlantic or Pacific) since 1945
  • number of species which have become endangered since 1945

Draw the imagined graphs, working individually or in pairs. To cross-check, students or pairs of students can exchange their "mental" graphs with another group who will compare the graphs to information from reliable sources.

[Sidebar
Make use of the sets of graphs in Global Change and Canadians to check student graphs. Sources that could be used are Global Change and Canadians, Statistics Canada's Human Activity and the Environment, Canada's State of the Environment 1991 or the annually issued UNDP Human Development Reports.]

1.2 EARTH TIMELINE

Make a geological time line for Earth history over 4.5 billion years. Use string and a meter stick. Decide on the scale, i.e. 1 cm = 1 million years. Mark major events on the scale (dinosaurs, the last ice age, etc.). Is your scale a good way to plot events? Why or why not? Try other scales:

1 m = 1 million years
1 m = 100,000 years
1 m = 10 million years

Do you have a better understanding of the history of the Earth? Of humanity's place on that scale? (See Appendix 1-Sample Lesson Plans for a more detailed description of this activity.)

[Sidebar This activity involves problem solving; students should help to determine an appropriate scale of measurement through trial and error. If 1 cm = 1 million years, is it possible to create a timeline on a piece of paper or do you need larger environments such as the classroom or the school yard?]

1.3 USING GRAPHS

 Examine the graphs in Global Change and Canadians. They can help to develop an understanding that global change has occurred over time, and before human activity became a part of the changing Earth ecosystem. Some key questions can be raised when investigating the information presented in Figure 1 (Global Change and Canadians, p.1).

  • Were there changes to the global ecosystem before humans?
  • What is the greatest change in temperature range, from low to high temperatures?
  • How long did it take for the temperature changes to occur?
  • Draw a line along the lowest temperature points. Along the highest temperature points. Is there a trend?
  • What are the possible causes of this trend?
  • How does this trend relate to Canada's climatic changes?

Extrapolate: using Figure 1, try extrapolating the graph lines into the future. Is it possible to extrapolate? What are the risks? How certain are you? Is the planet on a systematically rising scale of temperature change? Could there be a downswing in the graph line?

1.4 GLOBAL CHANGE ISSUES-WHAT ARE THEY?

There is a tendency to measure global change only in terms of global climate change. It is important to understand that global change includes global climate change, but does not equate only with global climate change. Figure 2 (Global Change and Canadians, p.4) presents Local Temperature Change, Methane Concentration, and Carbon Dioxide Concentration over the past 160,000 years. Compare these graphs and notice similarities, trends, and any anomalies that exist. These all deal with temperature change; what other global change issues are there? What other measurements can indicate global change trends?

1.5 IDENTIFY ELEMENTS OF GLOBAL CHANGE

Create a classroom mural, using drawings, photos, magazine pictures. Include items that relate to: deforestation, pollution, ozone depletion, species loss, erosion, climate change, population growth, excessive consumption, and third world poverty. Where capability exists, create an audio-visual slide production or video.

[Sidebar
Creating murals, drawings, models videos and other "hands on" activities can help teachers address a variety of learning styles and add an exciting creative element to classroom activities, at any educational level.]

1.6 COMPARISON TABLE

Compare human and non-human causes of global change. Create a table indicating which global changes are caused by human activity, and which are caused by non-human activity. Remember that some issues are the product of natural variability and human-induced changes. Your chart may look something like this:

Global change issueHuman causeNon-human cause
Species lossover-hunting, habitat destructionIce Age
Climate changeburning fossil fuelsvolcanic activity
Mountain building * shifting earth's crust
Human impact on the environment can be caused by global or regional factors. Relate human activity within the local region to global change.

[Sidebar Your table may look different, and should include a much more comprehensive list of issues and causes.]

1.7 ECOSYSTEM IN A JAR

This is an activity which can be set up at the beginning of the year or unit and monitored over time. The key concept to address when using the Ecosystem in a Jar activity is that it takes many elements to make an ecosystem work. Each student or group of students should bring their own jar, and create their own ecosystem. A field trip to a local pond or swamp to gather ecosystem materials is an excellent way to point out the elements needed to make an ecosystem, and to provide students with an opportunity to investigate the elements that make up a specific ecosystem (swamp or pond). The ecosystem jars can be manipulated and monitored, demonstrating to students what can happen if one or more elements of life are altered. (See Appendix 1- Sample Lesson Plans for a more detailed description of this activity.)

Failure to produce a thriving ecosystem should not be considered as a worthless exercise. On the contrary, it may serve to illustrate the complexity of such an ecosystem and the difficulty of its duplication on such a scale. Ask students to speculate on why it was difficult to recreate the ecosystem in the jar.

[Sidebar
This activity spans a number of weeks. It can be started at the beginning of a unit on global change and monitored over a long period of time. The ecosystem created can provide the basis for ongoing experimentation and journal-keeping.]

1.8 A RECIPE FOR A STABLE ECOSYSTEM

What are the ingredients needed to support life? Write a recipe for a stable ecosystem.

1.9 MAKING MODELS

Plan a Model Biosphere. Create plans and models of a biosphere designed to support a given number of students within a square block of land. In rural areas, the equivalent in hectares may be used for the land scale. The biosphere model will be sealed, and students will have the opportunity to determine what the essential elements are, and how much of each will be available. Questions that arise out of this activity include: What is needed in the biosphere? What could disrupt the stable environment within the biosphere? How many students can be supported in the biosphere, given the fixed size?

As an activity extension, ask students to compare their model to that of Biosphere II. Biosphere II is an engineered environment located in the southern United States that was inhabited by eight researchers for two years (1991-1993). Consult your resource centre or teacher-librarian to obtain information on Biosphere II.

Assessment

Assessment should focus on how well students were able to perform tasks assigned to them. For example:
  • What is global change? Were students able to define global change?
  • What are the issues around global change? Were students able to delineate the causes of global change by listing them, by creating a mural demonstrating knowledge of those problems, by creating a chart differentiating the human and non-human causes of various global changes?
  • Time scale. Were students able to make a time-line with an appropriate scale and indicate major global changes (major geo-historical events) on the scale? Did they interpret graphs showing global changes over time? Were they able to make their own personal timeline and relate changes in thei lifetimes to global changes?
  • Were students able to demonstrate an understanding of the interactions and complexity of Earth systems? Some of the activities that could provide a basis for assessment of that understanding include creating an Ecosystem In A Jar, describing the elements of a balanced ecosystem by writing a "recipe" for a healthy ecosystem, and planning (or building) a model for a "biosphere" project.
TABLE OF CONTENTS | CHAPTER ONE: WHAT IS GLOBAL CHANGE? | CHAPTER TWO: WHY IS GLOBAL CHANGE IMPORTANT TO CANADA | CHAPTER THREE: THE CAUSES OF GLOBAL CHANGE | CHAPTER FOUR: THE CONSEQUENCES OF GLOBAL CHANGE | CHAPTER FIVE: HOW WILL GLOBAL CHANGE AFFECT SOCIETY? | CHAPTER SIX: CANADIAN RESPONSES TO GLOBAL CHANGE | APPENDIX | CREDITS

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