"The history of life on the earth has been a history of the interaction between living things and their surroundings." For most of this history, their environment has influenced vegetation and animals. Only recently in history have vegetation and animals influenced the environment. It is primarily people who have caused this change. The change has increased immensely in the past twenty-five years. People have contaminated the environment with dangerous and deadly chemicals.
These poisons can't be removed once they've been put into the earth. For example, Strontium 90 is a chemical that is released when there's a nuclear explosion. The chemical falls from the sky and lands on the earth where it enters into the chemical make-up of grass, corn, wheat, and other living things. It even enters the bones of human beings and it never leaves. Other examples are chemicals that are sprayed on crops and forests. They also stay in the soil and enter into living organisms. They pass from one organism to another. They also move in underground streams and then emerge into the air where they kill vegetation and poison animals of all kinds. People don't know all that they create when they put these chemicals into the atmosphere.
The history of life on the earth is hundreds of millions of years long. Things took that long to get to the balance where they are now. The environment has always contained both harmful and helpful elements. For example, some rocks give out dangerous radiation. Even the sun is dangerous in that it gives out short-wave radiation. The balance of nature, that which balances the dangerous and the good, happened over many years. In the modern world, though, time is not long like this. Major environmental changes happen in an instant. People have caused this speed up. Now, radiation isn't just coming from rocks; it's also coming from scientists tampering with the atom. Now, the chemicals of the natural world exist alongside the synthetic chemicals people have made.
Unlike the natural process of chemicals coming into the world where the earth takes millions of years to adjust to it, there is no such time for the earth to adjust to every synthetic chemical introduced into the world. There are five hundred new chemicals introduced each year. Most of these chemicals are used in the "war against nature." People want to kill insects and other living things they think of as pests. They are applied on yards, in homes, on farms and in many other places and they kill both good and bad insects. These things should be called "biocides" instead of "insecticides" because they kill all living things, not just insects.
The use of insecticides has escalated since the U.S. government started letting civilians use DDT. The reason for the increase is that insects have evolved to become immune to insecticides almost as fast as they've been introduced. So each time one insecticide becomes obsolete, a stronger, more deadly one is introduced. There's a phenomenon called "flareback." This happens when the insect population increases after it's been bombarded with sprays.
People are very worried about the threat of a nuclear war destroying the planet. They should think about the use of these chemicals that are being poured into the environment. These chemicals get into the tissues of plants and animals. They even get into the germ cells so that they will change the material of heredity. Some people are thinking about engineering people's genes. They don't seem to recognize the fact that another kind of engineering is happening inadvertently already.
This deadly change has been caused by something that seems completely irrational. People have poisoned the whole earth and all its creatures just to kill a small number of unwanted species. The irrationality extends further. In the United States, farmers have been given money by the government to make them cut back on how much they produce. At the same time, people will hear the argument that farmers need to use pesticides so they can increase production. Insects certainly need to be controlled, but they need to be controlled in rational and careful ways.
It's useful to look at the history of insects. They were around long before people were. They were very adaptable and very varied. Since people came around, a small percentage of insects have come into conflict with them. They compete for food and they carry disease. The disease-carrying insects are found where people live in very crowded conditions and where they don't have good sanitation. In these situations, control of insects is necessary. The startling news is that the control has been inept and has often made things worse instead of better.
Before the use of present day farming techniques, farmers had little trouble with insects. These problems came along with the introduction of singe-crop agriculture. This system made explosive increases in insect populations inevitable. Nature works by a principle of variety creating the conditions of balance. If there are many kinds of plants, the insect that lives on one of those plants only has a limited amount of food. If there is one kind of plant, the insect that lives on that kind of plant has unlimited amounts of food. The same situation works with other kinds of plants. For example, it was once popular to line the streets of cities with elm trees. Suddenly one kind of beetle practically wiped out all those trees. If elms had only been one kind among many kinds of trees, that insect never would have gotten out of hand.
Another problem increases insect populations. It's the worldwide migration of plants and insects. During the Cretaceous Period, a hundred million years ago, floods cut off land bridges from one continent to another. Living things were isolated and they developed many new species. Then, some of these land masses joined again about 15 million years ago and the species that had been formed began to move around. Now this movement of organisms is being helped by people who move them intentionally and accidentally. There are many plants imported each year into the United States. It has introduced over 200,000 plants. Half of the 180 major insect enemies of U.S. plants were introduced from abroad; most have come on these introduced plants. When these new plants and animals get to new territory, they don't have the restraint of natural enemies to keep their population down. That way they become enormously abundant.
People have tried to stop the spread of invading plants and animals through quarantine and through massive chemical spraying, but these have been ineffective methods. What we need to do is to find out about the plants and animals, especially about how they interact with their environment. That way we can promote a healthy balance. We actually already have much of this knowledge, but we don't use it. There are many alternatives to the use of chemicals but people don't use them.
The people who have control over these chemicals usually don't know very much about them. They work zealously on stamping out unwanted plants and animals. Carson isn't against the use of chemicals at all. The problem is that these chemicals have been controlled by people who don't know what they're doing and don't know the harm they're causing. The Bill of Rights doesn't guarantee people in the United States to be secure against lethal poisons that are distributed by individuals or public officials, but that is only because the framers of the Constitution didn't foresee the problem. These chemicals have been used without considering their effect on the soil, the water, the wildlife or on people. Most people don't know how big this problem is. Specialists only know about their area. Corporations make sure that their chance for profits isn't impeded. The U.S. public should be the ones to decide these matters.
The first substantive chapter of Silent Spring gives an excellent introduction to the causes of the problem of pesticides and other chemical poisons in the United States. It gives an overview of the history of insects and the way people have intervened in that history. Its aim, of course, is persuasive. Carson never forgets to bring the information to the reader purposefully: to show the reader the dangers of the present course of action and to urge the reader to do something about it.