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Key Themes in Environmental Sciences

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Presentation on theme: "Key Themes in Environmental Sciences"— Presentation transcript:

1 Key Themes in Environmental Sciences
Chapter 1 Key Themes in Environmental Sciences

2 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

3 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.

4 Population change since 1950 projected to the year 2150 for major areas of the world, medium fertility scenario. The population of Africa will nearly quadruple. The only major area whose population is projected to drop over time is Europe – from 728 million to 595 million, a decline of 18% over 155 years. © 2008 John Wiley and Sons Publishers

5 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.

6 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?

7 Sustainability Sustainable resoruce harvest Sustainable ecosystem
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

8 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

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

10 Science as a Way of Knowing
Chapter 2 Science as a Way of Knowing

11 Science is a process of discovery
Science as Process Science is a process of discovery Scientific ideas change Sometimes a science undergoes a fundamental revolution of ideas

12 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.

13 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.

14 Refers to Case Study: Birds at Mono Lake: Applying Science to Solve an Environmental Problem.
Used as an example of how scientific information is needed to answer key questions. © 2008 John Wiley and Sons Publishers

15 Science as Process Scientific Method: Actually a set of methods which are the systematic methods by which scientists investigate natural phenomena

16 © 2008 John Wiley and Sons Publishers


18 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.

19 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.

20 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


22 Observations, Facts, Inferences, and Hypotheses
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.

23 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.

24 Used to depict the dependent and independent variable
Used to depict the dependent and independent variable. Photosynthesis as affected by light. Light is the independent variable, uptake is the dependent variable. © 2008 John Wiley and Sons Publishers

25 Observations, Facts, Inferences, and Hypotheses
Model: A deliberately simplified explanation of complex phenomena. Models are often physical Mathematical Pictorial or Computer-simulated

26 A computer simulation of forest growth, used as an example of a model
A computer simulation of forest growth, used as an example of a model. This kind of model is becoming increasingly important in environmental sciences © 2008 John Wiley and Sons Publishers

27 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

28 Scientific investigation as a feedback process.
If the hypothesis is shown to be consistent with observations in some limited experiments, conduct additional experiments to test it further. If the hypothesis is rejected, make additional observations and construct a new hypothesis © 2005 John Wiley and Sons Publishers

29 Science, Pseudoscience, and Frontier Science
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

30 Pseudosciencentific ideas arise from various sources
© 2008 John Wiley and Sons Publishers

31 Dollars and Environmental Sense: Economics of Environmental Issues
Chapter 28 Dollars and Environmental Sense: Economics of Environmental Issues

32 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

33 The Environment as a Commons
Land or another resources owned publicly with public access for private uses



36 Externalities Externality (Indirect Cost) Direct Costs
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


38 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


40 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

41 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

42 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

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