Chapter 1 Key Themes in Environmental Sciences. Major Themes of Environmental Science Human...

Chapter 1

Key Themes in Environmental Sciences

Major Themes of Environmental Science

• Human population growth

• An urbanizing world

• Sustainability of our population and all of nature

• People and nature

• A global perspective

• Science and values

Human Population Growth

• The human population grew at a rate unprecedented in history in the twentieth century.

• Population growth is the underlying environmental problem.

• Famine is one of the things that happen when a human population exceeds its environmental resources. An example is African Famine.

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An Urban World

• When the impact of technology is combined with the impact of population, the impact on the environment is multiplied.

• In an increasingly urban world, we must focus much of our attention on the environments of cities and on the effects of cities on the rest of the environment.

Sustainability and Carrying Capacity

• What is the maximum number of people the Earth can sustain?

• As of 2013, what is the population of the Earth?

Sustainability

• Sustainable resoruce harvest– An amount of a resource that can be

harvested at regular intervals indefinitely

• Sustainable ecosystem– An ecosystem that is subject to some human

use, but at a level that leads to no loss of species or of necessary ecosystem functions

Science and Values

• To make decisions about an environmental problem we:– Know what is possible based on science– Choose the best option based on our values

Precautionary Principle

• Precautionary Principle states that we should not wait for scientific proof before taking action to prevent environmental damage.

Chapter 2

Science as a Way of Knowing

Science as Process

• Science is a process of discovery–Scientific ideas change

–Sometimes a science undergoes a fundamental revolution of ideas

Science as Process

• The criterion by which we decide whether a statement is in the realm of science:

Whether it is possible, at least in principle, to disprove the statement.

Disprovability• If you can think of a test that

could disprove a statement, then that statement can be said to be scientific.

• If you can’t think if a test, then the statement is said to be nonscientific.

© 2008 John Wiley and Sons Publishers

Science as Process• Scientific Method:

Actually a set of methods which are the systematic methods by which scientists investigate natural phenomena

© 2008 John Wiley and Sons Publishers

Assumptions of Science

• Events in the natural world follow patterns that can be understood through careful observation and scientific analysis.

• These basic patterns and rules that describe them are the same through the universe

• Science is based on a type of reasoning known as induction

• Generalizations can be subjected to tests that may disprove them.

• Although new evidence can disprove existing theories, science can never provide absolute proof of the truth of its theories.

The Nature of Scientific Proof

• Deductive reasoning:– Drawing a conclusion form initial definitions

and assumptions by means of logical reasoning.

• Inductive reasoning:– Drawing a conclusion from a limited set of

specific observations.

Measurements and Uncertainty

• Experimental errors:– Measurement uncertainties and other errors

that occur in experiments.

• Accuracy:– The extent to which a measurement agrees

with the accepted value

• Precision:– The degree of exactness with which a

quantity is measured

Observations, Facts, Inferences, and Hypotheses

• Observations:– The basis of science, may be made through any of

the five senses or by instruments that measure beyond what we can see.

• Inference:– A generalization that arises from a set of

observations.

• Fact:– When what is observed about a particular thing is

agreed on by all or almost all.

Observations, Facts, Inferences, and Hypotheses

• Hypothesis:– An explanation set forth in a manner that can

be tested and is capable of being disproved.

• Dependent variable:– A variable taken as the outcome of one or

more variables.

• Independent variable:– The variable that is manipulated by the

investigator; affects the dependent variable.

© 2008 John Wiley and Sons Publishers

Observations, Facts, Inferences, and Hypotheses

• Model:– A deliberately simplified explanation of

complex phenomena.– Models are often

• physical• Mathematical• Pictorial

or• Computer-simulated

© 2008 John Wiley and Sons Publishers

Observations, Facts, Inferences, and Hypotheses

• Theories: Models that offer broad, fundamental explanations of many observations

• Hypothesis: A possible solution to a problem• Inference: Inference is the act or process of

deriving a conclusion based on what one already knows or on what one assumes

• Fact: Something that actually exists• Scientific Law: A scientific law or scientific

principle is a concise verbal or mathematical statement of a relation that expresses a fundamental principle of science

© 2005 John Wiley and Sons Publishers

Science, Pseudoscience, and Frontier Science

• Pseudoscience:– Some ideas presented as scientific are in fact

not scientific, because they are • untestable, • lack empirical support, • or are based on faulty reasoning or poor

scientific methodology

© 2008 John Wiley and Sons Publishers

Chapter 28

Dollars and Environmental Sense: Economics of Environmental Issues

The Economic Importance of the Environment

• Environmental Economics– The study of relationships of the importance of the

environment to the economy– Includes:

• The impact of environment as a result of economic activity

• Regulation of the economy and economic processes• The objective of balancing environmental and economic

goals of society• Development of economic policy to minimize

environmental degradation• Finding solutions to environmental problems

The Environment as a Commons

• Commons:– Land or another resources owned publicly

with public access for private uses

Externalities

• Externality (Indirect Cost)– An effect not normally accounted for in the

cost-revenue analysis of producers and often not recognized by them as part of their costs and benefits

• Direct Costs– Those borne by the producer and passed

directly on to the user or purchaser

Risk-Benefit Analysis

• Def: The riskiness of a present action in terms of its possible outcomes

• The relation between risk and benefit affects our willingness to pay for an environmental good

• Evaluation of environmental intangibles is becoming more common in environmental analysis

• When quantitative, such evaluation balances the more traditional economic evaluation and helps separate facts from emotion in complex environmental problems

How Do We Achieve an Environmental Goal?

• Moral suasion• Direct controls• Market processes• Government investment

• Many controls have been applied to the use of desirable resources and the control of pollution

Marginal Costs and the Control of Pollutants

• Marginal Costs: the cost to reduce one additional unit of pollutant

• 3 methods of direct control of pollution– Setting maximum levels of emission– Requiring processes and procedures– Charging fees for emission