1. Environmental Science
Chapter 1: Studying the State of Our Earth

2. Let’s review some terms
Environment
Environmental science
System
Ecosystem
Biotic/abiotic
Environmentalist

3. Environmental Indicators
Are Earth’s life-support systems being degraded by human-induced changes?
Ecosystem services: clean water, timber, fisheries… ?
Indicators show the health and quality of a natural system – not necessarily the cause
Five to focus on in this course:
Biological diversity (genetic, species, ecosystem)
Food production
Global climate
Human population
Resource depletion

4. Sustainable practices
Requirements:
Environmental systems cannot be damaged beyond their ability to recover
Renewable resources must not be depleted faster than they can regenerate
Nonrenewable resources must be used sparingly
Ecological footprint
Energy, settlements, timber and paper, food and fibers, seafood, carbon footprint, built-up land, forests, cropland and pastures, fisheries, minerals

5. The process of science Observations and questions
Forming a hypothesis – what, exactly, is an ‘educated guess’?
Null hypothesis – the statement that can be proved wrong
Collecting data
Important considerations: replication, sample size, accuracy, precision, uncertainty
Interpreting results
Inductive reasoning versus deductive reasoning
Disseminating findings
Terms to keep in mind: critical thinking, theory, natural law

6. Experimental design Controlled experiment Natural experiment
One variable to test!  independent variable
One group gets the test!  experimental group
The test causes the result!  dependent variable
The other group allows us to compare!  control group
Natural experiment
A natural event acts as an experimental treatment in an ecosystem
Example: study of forest regrowth after a volcano

7. Challenges of environmental science
Lack of baseline data for comparison – there is no ‘control’ planet without humans
Subjectivity – one man’s trash is another man’s treasure… but what about the ecosystem?
Interactions – natural systems are extremely complex
Human well-being – people who are struggling to get their basic needs met are less concerned for environmental issues. These same people may be more impacted by environmental problems.