Unit B3



People who live on small islands know that their island environment is limited. They see those limits every day. They know that if they are not careful they can use up all of a resource, such as fresh water or a favourite kind of fish, and have nothing left. They know that, if they dirty or poison their island, they cannot easily get away from it.

This world on which we live is also like an island in the great ocean that is space. On a larger scale it has the same kinds of limits as a small island in the ocean. Before, we could not easily see those limits, and man did not think much about them. But now men have gone into space and have taken pictures of their world island.

New Technology

With modern science and technology, man has learned to make bigger and bigger changes in the world. When he had only stone axes, he could not cut down many trees, but now with modern machines he can easily cut down whole forests. We do everything on a much bigger scale then ever before. In the past, the world seemed too big for men to have any effect on it. There were important changes, but they generally occurred so slowly that it took generations to notice them. In any one person's lifetime, the world stayed much the same as he or she had always known it. Today we can change the face of the planet. We make gardens out of deserts in some places, and deserts out of gardens in others. We catch so many fish in the oceans that the populations collapse. We move mountains (if there are minerals worth mining inside). We can probably cut all the major areas of tropical forest in the lifetime of our children. If we are foolhardy enough to use the nuclear weapons we have made in large numbers, we could even exterminate all life on the planet.

We have such power at our disposal that we can now change the world environment, but we do not yet have enough knowledge to do so wisely. So we continue doing what we have been doing, hoping that the changes we bring about will not be too disastrous. It is a risky way to prepare for the future.


The basis of many of the problems in the world environment is the growing world population. There are far more people then there ever have been before, and our numbers have already doubled twice in this century. No one knows how many people can comfortably live on our planet. Some experts think we already have too many; others expect we can always develop new resources when they are needed. Part of the problem is that the numbers of people are growing much too rapidly in many countries for us to keep up with the need for new houses, new schools, new jobs and more food. The increasing numbers of poor people in many developing countries are often forced to strip the forests of their trees for fuel, clear and farm the land until it is exhausted or has eroded away, pollute their water, and strip every living thing from the expanding deserts in their desperate attempt to survive. Even so, millions die from starvation and disease.

Consumption and Pollution

The poor are not the only ones to cause environmental problems. The rich consume far more than their share of the world's resources, often very wastefully. They are primarily responsible for the rapid exhaustion of many of the world's non-renewable resources (minerals and fossil fuels like oil), producing at the same time most of the global pollution. The developed nations are now wallowing in their own filth, so to speak. The gases from automobiles, industrial smokestacks and generating plants produce acid rain that is killing forests and sterilizing lakes over large areas of Europe and North America. Industrial chemicals and wastes carelessly dumped or buried years ago are now poisoning neighbourhoods and water supplies. Some modern chemicals break down slowly or not at all; they are becoming long-term contaminants of the whole planet. Others may be rising up into the atmosphere where they may destroy the protective ozone layer that keeps us from being burned by the sun. Pesticides may spread and go on killing long after their initial use. Scientists are only now discovering that some materials and chemicals in common use cause cancer or deformed babies. Developing countries are increasingly suffering the same kinds of problems, and their resources for protection and control are much more limited.

Changing Climate

The human race has now developed to the point that its activities can affect the whole world system. We have burned so much fossil fuel and cut down so much forest that we have caused carbon dioxide gas (produced by burning or decaying organic matter) to build up in the atmosphere in ever larger quantities. One property of this gas in the air is that it traps heat from the sun much as a window or corrugated iron roof does. Science suggests that global warming and climate change will result, and this could alter world weather patterns, causing droughts in some areas and unusual rains or floods in others. This would be catastrophic for agriculture and for many other human and natural activities. It could also cause the level of the oceans rise. It would not take much of a rise in sea level for some low-lying islands to disappear.

Declining Productivity

Another worrying trend in the world environment is the continuing destruction of the natural ecosystems and primary productivity of the planet. Primary productivity is the process by which plants trap energy from the sun and turn it into food and materials. Almost all life depends directly or indirectly on this food for survival. Even the energy in our oil and coal was first trapped by plants ages ago. The amount of primary productivity thus determines how much life (and how many people) can survive on this planet. Yet man is busily cutting down the forests, poisoning the oceans, and misusing land so that the deserts spread. More and more land is stripped, degraded and abandoned. The resources that are lost are those that could be renewed indefinitely if properly cared for. More and more kinds of plants and animals are becoming extinct; they can never be brought back, and the world is that much poorer for their loss.

Exhaustion of Resources

At the same time, the resources that are the basis of most modern industry are not renewable. Most minerals occur only in limited quantities on the planet, at least in forms or concentrations that can be mined economically. We are rapidly exhausting the richest and most accessible ores of these minerals (copper, aluminum, iron, nickel, phosphate, etc.). The same thing is happening with the fossil fuels (oil, coal, natural gas) which provide most of our energy. As the costs of the raw materials go up, industries become less and less economic. Some materials are expected to run out in a few decades. This will force painful changes in industrial societies with great social and economic consequences.


Looked at all together, the trends in the world situation are frightening. The numbers of people are increasing just as the productivity of the planet is declining and many important resources are running out. Pollution is spreading and the weather could become more unstable. The result is that there is less and less to support more and more. These trends cannot continue for ever. At some point the "crunch" has got to come.

It is clear that the world society cannot go on indefinitely as it has without paying attention to world limits. If we do not change voluntarily, the changes will be forced upon us, and there will probably be great suffering in the process. The longer we wait to act, the harder the change will be. Unfortunately, no one can agree as to how we should change, or in what direction, at what speed, and who should bear the costs. These problems are as much political and moral as technological, and are beyond the scope of this unit, although every concerned person should think about them.



What are some of the limits to the island environment?

How is the world similar to an island?

What are some of the limits to the world environment?

New Technology

How has new technology made it easier to clear land?

What has technology done to help agriculture?

What are some new fishing technologies?

How have new technologies in communications and transportation changed life in the islands?

In what ways has technology made it possible to change the world environment?


How many people were there in the world in 1900?

How many are there today?

How many are there projected to be at the end of this century?

What was the population of your country or island in 1900, and today?

Is the population of your island increasing, stable or decreasing?

What is the reason for this change?

If this trend continues, what will your island be like in 20 or 50 years time?

What environmental problems are caused by large numbers of poor people?

Consumption and Pollution

Why do the rich developed countries use more than their proportional share of the world's resources?

What are some of the environmental problems of materially developed countries?

What materials that you use did not exist a hundred years ago?

Where do these materials go, and what happens to them, when you have finished using them?

Changing Climate

What has man done that might change the climate?

What would happen on your island if the climate changed?

What would happen to your island if the sea level rose 50 cm (20 in.)?

Declining Productivity

How much forest is left on your island?

How much land is used for agriculture?

How much land is degraded or not useful for anything?

How much of your island has changed from forest to agricultural land or from agricultural land to degraded land in the last 100 years?

Have the reefs or coastal waters of your island been degraded or become less productive?

What would your island be like if almost all the land became degraded?

What would happen to the world if almost all the land became degraded?

Are there any parts of your island that have become more productive?

Do you know of plants or animals on your island that are now very rare or that have disappeared (become extinct)?

Have some kinds of forest or natural areas disappeared completely?

Exhaustion of Resources

Is there any mining in your country?

How long is the mining expected to continue?

Is the mine doing as well as when in first started, or is the quality of the ore declining?

What will happen when there is nothing left to mine?

What happens to the price of something if many people need it and it becomes harder to find?

How are materials like copper or oil (and oil-based products like plastic) used in your country?

Imagine what would happen if the world ran out of something important like oil or copper?

What kinds of resources will never run out if they are taken care of?


What happens when there are more people but less food?

If it was no longer possible to import food to your island, what would be the result?

What would happen on your island if oil runs out and there is much less or much more expensive transportation?

How would you feel if someone somewhere else poisoned your air or land?

Is there a relationship between environmental problems and war or peace in the world?

Instructions for trainers in the use of this unit

Return to Small Island Environmental Management Home Page
Return to Islands Home Page

UN System-Wide Earthwatch Coordination
Updated 5 April 1998