Chapter Summary

Humans inhabit two worlds: one of nature and another of human society and technology. Environmental science is the systematic study of the intersection of these worlds. An interdisciplinary field, environmental science draws from many areas of inquiry to help us understand the worlds in which we live and how we might improve both of them.

The most amazing features of our planet may be the self-sustaining ecological systems that make life possible and the rich diversity of life that is part of, and dependent upon, those ecological processes. In spite of the many problems that beset us, the earth is wonderfully bountiful and beautiful.

Science is a way of exploring and understanding the world around us. It depends on making careful observations of natural phenomena and on formulating reasonable theories to explain those observations. Science rests on certain assumptions such as that the world is understandable and that we can learn about how things work through careful empirical study and rational analysis. Scientists strive to be methodical, rigorous, and unbiased. They also are skeptical, reserve judgment, and generally consider conclusions and interpretations to be conditional because new information can always overturn what we think to be true. Scientists can use either deductive reasoning (arguing from laws or general theories to specific detail) or inductive reasoning (using individual observations to derive general rules). In either case, scientists formulate testable hypotheses (provisional explanations) based on their inferences, and attempt to test them through experimentation or looking for evidence in nature. Once a substantial body of evidence has been accumulated and a consensus emerges within the scientific community, an explanation is considered a theory.

Statistics and probability are important concepts in environmental science. Descriptive statistics help us assess the general state of a group. Using a large, random sample helps prevent errors that arise from variations within the study group. Confidence levels represent the likelihood that your results are in error. Scientists usually compare values to a 95 percent confidence level, or a probability of 5 percent or less that the conclusions are misleading.

Critical thinking shares many of the aspects of logical, analytical thinking but also includes empathy, context, and justice in its search for truth and meaning.

Unprecedented population growth, food shortages, scarce energy supplies, air and water pollution, and destruction of habitats and biological resources are all serious threats to our environment and our way of life. As international travel and communication become easier, we realize that these problems encompass our whole planet and require global cooperation to find solutions. Still, there is good news. Pollution has been reduced and population growth has slowed in many places. Perhaps we can extend these advances to other areas as well.

The 20 percent of us in the world’s richest countries consume an inordinate amount of resources and produce a shocking amount of waste and pollution. Meanwhile, at least 1.3 billion people live in acute poverty and lack access to an adequate diet, decent housing, basic sanitation, clean water, education, medical care, and other essentials for a humane existence. Faced with immediate survival needs, the poorest poor often have little choice but to overharvest resources and reduce long-term sustainability for themselves and their children. Development means a real increase in standard of living for the average person. Sustainable development attempts to meet the needs of present generations without reducing the ability of future generations to meet their own needs.

Indigenous or native peoples are generally among the poorest and most oppressed of any group. Nevertheless, they possess valuable ecological knowledge and remain the guardians of nature in many places. Recognizing the rights of indigenous people and minority communities is an important way to protect natural resources and environmental quality.