Post on 13-Dec-2015
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.
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
• 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.
• Ex. San Francisco
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.
Science as Process• Scientific Method:
Actually a set of methods which are the systematic methods by which scientists investigate natural phenomena
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.
Observations, Facts, Inferences, and Hypotheses
• Model:– A deliberately simplified explanation of
complex phenomena.– Models are often
• physical• Mathematical• Pictorial
or• Computer-simulated
Observations, Facts, Inferences, and Hypotheses
• Theories:– Models that offer broad, fundamental
explanations of many observations
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
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