EC7. Neighborhood and Global Stewardship

cover for GSS book Ecosystem Change

Chapter 7

{ Ecosystem Change Contents }

The citizens of the United States use more energy and resources per person than do people in other countries.

Cardboard for recycling

What can we do to reduce our individual and collective impact on earth’s global system? On the pages that follow, we have described some actions taken by students to help solve environmental problems afflicting their communities. 

How much does your family recycle?

Does your school have a recycling program? Individuals can make a big difference when they work together. The average American throws away 4.5 pounds of trash a day and pays about $1.50/day to have it carted to a landfill.

When you recycle one aluminum can, you save enough energy to operate a television set for three hours. You can help persuade others to join in waste reduction efforts by calculating how much you are saving in natural resources and family expenses.

Berkeley recycling bin with cans
Recycle cans?
Berkeley recycling bin with bottles
Recycle bottles?

I. Waste Busters: Recycling at Home and at School

Students from all areas of the state of Washington have been collaborating with the Pacific Science Center to drastically reduce the amount of resources wasted in their State. They use the mathematics of recycling to help persuade families and schools that money and resources can be saved by everyone.

Items which have been recycled in different areas of the country include newspaper, white and colored paper, cardboard, glass, aluminum and tin cans, motor oil, batteries, certain plastics, yard clippings, and Christmas trees.

  • How much household waste does your family generate in one week? In one year? Find out by weighing the family trash and garbage using a bathroom scale.
  • Start or expand the recycling you do at home. Start a compost area in your yard. Keep a record of the weights of the materials such as paper, plastic, glass, and aluminum you recycle so that you can calculate the resource savings later.

Students from Peoria Elementary School with packages of used milk cartons.  Denver Schools are returning all their milk cartons to the Ex Cello Corp for reprocessing. 
Photo by Bruce McAllister via Wikimedia Commons

Returning milk cartons from a school to the company

EC7.1. Investigation:
Environmental Savings for Recycling

For every ton (2,000 pounds) of paper that is substituted for wood pulp in the manufacturing process:

  • 17 trees are saved
  • 60 pounds of air pollutants aren’t emitted
  • 7,000 gallons of water are saved
  • Enough energy is saved to power the average home for 6 months
  • landfill space is saved (2.5 cubic yards is saved for paper; 4 cubic yards for cardboard)


  1. Calculate the number of trees you will save by recycling paper for one year.
  2. Calculate how many trees could be saved if every student in your class recycled paper for one year?
  3. Write an article for your local newspaper to publicize your efforts and attract more community support.
  4. Conduct a survey at your school to find out what percentage of students recycle at home and at school.
  5. Get together with some of your classmates and start an awareness program on recycling at your school to increase student participation.
  6. Get a baseline measurement of how much is being recycled at the beginning of the program then monitor your progress.

II. Another Look at Gaia

Studying ecosystems is complicated and frustrating because many of the puzzle pieces are invisible and hard to measure. Global changes such as the atmospheric increase of carbon dioxide and the spread of DDT provide compelling reasons for cooperation in research and public education. 

The Gaia Model

Diagram of The Gaia Model

When the Gaia hypothesis was first proposed many scientists were turned off by its poetic interpretation.

The image of Gaia as a tremendous living organism living on the Earth and creating environmental conditions that would be beneficial for life seemed more like science fiction than science fact. As more ways in which living organisms modify the environment for their benefit have been discovered the Gaia concept has become more respectable.

Also the original hypothesis has been modified. James Lovelock now explains the concept as follows: The physical systems of the Earth and the life on it have evolved together as a single, tightly interlocked system. He explains that through a series of feedback mechanisms this system operates to hold the temperature of the planet within a range that is more or less acceptable for the continuation of life as a whole. 

The Gaia hypothesis has been very useful in stimulating a new way of looking at and making models of natural systems. In studying your terrarium, have you noticed relationships within the system that help maintain life? The growth of plants, for example, can provide food and oxygen for small animals. 

The smaller an ecosystem is, the more vulnerable it is to outside influences and the less likely it will provide all the requirements for particular life cycles. Overpopulation of one organism may exceed the carrying capacity of the system and trigger rapid changes and loss of diversity. 

Question 7.1. 
What limitations and positive feedback responses have you identified that threaten the health of your terrarium system? 

Read the science fiction story below and describe your explanations for the stability of this distant planetary system. How does matter and energy flow through this imaginary system?


EC7.2. Investigation:
Intelligence as a planetary scale process

Read all or part of the paper Intelligence as a planetary scale process (by Adam Frank, David Grinspoon and Sara Walker, Cambridge University Press). Look specifically for references to Gaia. Write down your thoughts about these ideas or discuss them with your friends, acquaintances, or relatives.

III. Daisy World Report

Bernard’s Star Planetary Mission: 30 Feb. 2297

From: Information Officer Janis II Hargrove

Our mission to Bernard’s Star is now entering Year 2. As reported earlier, we have confirmed and extended the observations of Earth astronomers. There are seven planets and a multitude of asteroids orbiting this star. However, only the second planet, at an average distance of 96 million miles from the star, has an atmosphere that contains oxygen and harbors life.

Daisy World, which is what we have taken to calling the planet, is extraordinarily like our Earth. Not only is the composition of its atmosphere almost identical, but its size, orbital distance, ratio of land to water and even its general climate is Earth-like. We have been able to work on the surface without life support systems. The “character” of the land surface is similar on all continents except right around the poles which are ice covered. The surface is mostly rolling hills almost completely covered with densely packed plants which constantly produce flowers resembling daisies. 

The daisy plants are quite amazing. The flower is 100 cm in diameter, and blooms all year. There are only two varieties, and they both grow quickly to a height of about 2 meters. The main difference between the two is in the color of the petals; one variety has black petals, the other has petals that are completely white. Near the equator the ground is covered with the white variety. In the polar regions the black plants dominate. In the temperate zones of both hemispheres, where the average temperature approaches 20° C, there is a mix of plants. 

We are at a loss to explain why this planet does not have the diversity of animal and plant species we have on Earth. Insect-like creatures seem to be the dominant animal life form, and we have found one that is definitely a carnivore! The climate seems to have remained nearly constant for a very long period. Preliminary studies of sedimentary rock layers indicate that they were formed under temperature conditions that have remained within a narrow range for thousands of years.

This long-term stability of the climate is very puzzling because on our approach to Bernard’s star our astronomers discovered a vast cloud of dust in an irregular orbit around the star. At different periods it cuts down on the light to Daisy World for months at a time. When the space between Bernard’s star and Daisy World becomes completely clear of dust, the amount of light energy reaching the surface increases greatly. It is a mystery to us how the temperature could remain the same, since changes in the output of the central star cause great changes in the climate of the other planets we have explored.

Question 7.2. 
What explanation do you have for the stable climate of Daisy World?

Question 7.3. 
What negative feedback mechanisms may be operating on the planet?

IV. People and the Biosphere

Two hundred years ago, more than three-quarters of the world’s land area was in its natural condition, undeveloped, unmapped and mostly unexplored. As humans have begun to dominate the earth, entire ecosystems have been transformed and the composition of the atmosphere changed in the relatively short period of time. Experience so far suggests that for some time at least, our activities will continue to produce changes that may generate far reaching positive feedback responses.

Throughout this unit, we have considered the characteristics of ecosystems and how they function. Evidence from numerous scientific studies reveals a long history of life on Earth, with the evolution of large numbers of species developing in a great variety of habitats. Each species has become adapted to a particular environment and a particular way of life. All the species in the biosphere interact with one another and the non living surroundings in a highly complex web of life that is linked by the recycling of nutrients, CO2, O2, water and minerals.

What is clear is that our effects on the biosphere result from the collective daily activities of every human being. Some effects of these in the future can be predicted. It is hard to avoid the conclusion that in the long run the future of humans and the biosphere depends to a great extent on how many of us there are, how each of us lives from day to day, and how we collaborate in becoming better stewards of our environment.

Humans have learned to survive the ice ages and the expansion of deserts. As a species, we are capable of tremendous adaptive changes in our behavior through education. Today we are faced with the challenge of forging a global effort to reduce human impact on the biosphere. Attitudes about pesticides and disposable containers have begun to change, and industry is beginning to provide materials that can be recycled and reused. Communities have begun to work together to protect and improve habitat for endangered species of plants and animals. We encourage you to look for other adaptive strategies that might help maintain Earth’s diverse ecosystems.

Write a Letter to the Future

Draw up a contract for yourself to reduce your impact on the biosphere by changing things you normally do. 

Leave a space for reporting your results 2 months from now.

Date the contract and seal it in an envelope labeled “Impact”. 

Address the letter to yourself and put a stamp on it.

Give the letter to your teacher, who will mail it to you in 2 months.

V. The Global Commons

The Gaia theory has shown us that the Earth is an interconnected planet in many ways. The many systems that regulate the flow of energy, carbon, oxygen and other nutrients throughout the planet are deeply interconnected. In a sense, we live in a Global Commons. Though we may live across the ocean from others or on the other side of the country, we share resources, breathe the same air and drink the same water. When the atmosphere has industrial pollutants or water is contaminated by sewage, it affects everyone eventually.

There are many difficult issues connected with how Earth’s wealth of life forms and environments are shared and conserved for future generations. The increase in carbon dioxide and other greenhouse gases due to human activity may cause global climate change in a relatively short period of time.

Most animal and plant species require many generations to adapt to environmental changes. Through the process called “natural selection,” genetic changes that improve an organism’s “fitness” for surviving in the altered environment get passed on to the next generation. The offspring of the “better adapted” organisms survive in larger numbers and produce more offspring in successive generations. Eventually the genetic character of the species is dominated by the new and more successful traits suited to the new environment.

The genetic characteristics of humans have also changed in this way over hundreds of thousands of years. But humans have prevailed as a dominant species mainly through their ability to adapt to new situations through learning. The process by which this adaptive behavior spreads among human populations is education, or in scientific terms, cultural evolution. For example, our modern knowledge of microorganisms has changed our systems of cooking, cleaning, washing, and using water for drinking.

If the rate of environmental change is fast, as has been predicted by many scientists who are studying global climate data, then it is likely many species of plants and animals will become extinct. It is true that there have been many mass extinctions throughout the history of life on earth precipitated by events such as asteroid impacts and volcanic eruptions. Following each environmental change, Earth’s surviving life forms have evolved new ways of surviving in the altered habitats. Humans have learned to survive the ice ages and the expansion of deserts. As a species, we are capable of tremendous adaptive changes in our behavior in the short time span of one generation. Today we are faced with the challenge of forging a global effort to reduce human impact on the biosphere. Attitudes about disposable containers have begun to change, and industry is beginning to provide materials that can be recycled and reused. Communities have begun to work together to protect and improve habitat for endangered species of plants and animals. We encourage you to look for other adaptive strategies that might help maintain Earth’s biodiversity as we explore scientific research, history, sociology, economics, geography, and other topics related to the Global Commons.

VI. Conclusion

As we have seen in our study of ecosystems, they are complex systems that depend on many factors to maintain them in a state of balance. However, we have also seen the destructive effects of human activities on our world. We live together on the Earth with all plants and animals, each of which needs its place to survive. We can all survive on our world but we need to work together to form better solutions for all if we want the complex model known as Gaia to work in a way that will ensure the survival of all inhabitants of Planet Earth.

See Staying current for this chapter.