Chapter 1Introducing Environmental Science and Sustainability

Overview of Chapter 1

Human Impacts on The Environment

Population, Resources and the Environment

Environmental Sustainability

Environmental Science

Addressing Environmental Problems

The Environment (Earth)

Life has existed on earth for 3.8 billion years

Earth well suited for life Water covers ¾ of planet

Habitable temperature, moderate sunlight

Atmosphere provides oxygen and carbon dioxide

Soil provides essential minerals for plants

But humans are altering the planet; not always in positive ways

Human Impact on the Environment

Satellite view of North America at night

Human Impacts on Environment—Population

Expected to add several billion more people in 21st

century

Earth’s Human Population is over 6 billion

Growing exponentially

Population

1 in 4 people live in extreme poverty

Cannot meet basic need for food, clothing, shelter, health

Difficult to meet population needs without exploiting earth’s resources

Gap Between Rich and Poor

Highly Developed Countries (HDC)

Complex industrialized bases, low population growth, high per capita incomes

Ex: US, Canada, Japan

Less Developed Countries (LDC)

Low level of industrialization, very high fertility rate, high infant mortality rate, low per capita income

Ex: Bangladesh, Mali, Ethiopia

Types of Natural Resources

Overpopulation

People overpopulation

Too many people in a given geographic area

Problem in many developing nations

Consumption overpopulation

Each individual in a population consumes too large a share of the resources

Problem in many highly developed nations

Ecological Footprint

The average amount of land, water and ocean required to provide that person with all the resources they consume

Earth’s Productive Land and Water 11.4 billion hectares

Amount Each Person is Allotted (divide Productive Land and Water by Human Population)

1.8 hectares

Current Global Ecological Footprint of each person

2.7 hectares

Ecological Footprint Comparison

IPAT Model

Measures 3 factors that affect environmental impact (I)

I = P A T

Environmental

Impact

Number

of people

Affluence per

person

Environmental

effect of

technologies

Environmental Sustainability

Environmental Sustainability

The ability to meet current human need for natural resources without compromising the needs of future generations

Requires understanding:

The effects of our actions on the earth

That earth’s resources are not infinite

Tragedy of the Commons

Garrett Hardin (1915-2003)

Solving Environmental Problems is result of struggle between:

Short term welfare

Long term environmental stability and societal welfare

Common pool resources

Garrett used Common Pastureland in medieval Europe to illustrate the struggle

Sustainable Development

Economic development that meets the needs of the present generation without compromising future generations

Environmental Science

An interdisciplinary study of human relationship with other organisms and the earth

Biology

Ecology

Geography

Chemistry

Geology

Physics

Economics

Sociology

Demography

Politics

Earth As a System

System A set of components that interact and

function as a whole

Global Earth Systems Climate, atmosphere, land, coastal zones,

ocean

Ecosystem A natural system consisting of a community of

organisms and its physical environment

System approach to environmental science Helps explain how human activities affect

global environmental parameters

Earth Systems

Most of earth’s systems are in dynamic equilibrium or steady state Rate of change in one direction equals that in

the other

Feedback Negative feedback- change triggers a

response that counteracts the changed condition

Positive feedback- change triggers a response that intensifies the changing condition

Feedback

Scientific Method

Controls and Variables in Experiment

Variable

A factor that influences a process

The variable may be altered in an experiment to see its effect on the outcome

Control

The variable is not altered

Allows for comparison between the altered variable test and the unaltered variable test

Inductive and Deductive Reasoning

Inductive Reasoning Used to discover general principles

Seeks a unifying explanation for all the data available

Ex: FACT: Gold is a metal heavier than water

FACT: Iron is metal heavier than water

FACT: Silver is a metal heavier than water

CONCLUSION (based on inductive reasoning): All metals are heavier than water

Conclusions reached with inductive reasoning may changed with new information

Inductive and Deductive Reasoning

Deductive Reasoning

Proceeds from generalities to specifics

Adds nothing new to knowledge, but makes relationships among data more apparent

Ex:

GENERAL RULE: All birds have wings

SPECIFIC EXAMPLE: Robins are birds

CONCLUSION (based on deductive reasoning): All Robins have wings

Five Stages to Addressing An Environmental Problem

Five steps are idealistic

Case Study: Lake Washington

Assessing Environmental ProblemCase Study: Lake Washington

Large, freshwater pond

Suburban sprawl in 1940’s

10 new sewage treatment plants dumped effluent into lake

Effect = excessive cyanobacteria growth that killed off fish and aquatic life

Scientific Assessment

Aquatic wildlife assessment done in 1933 was compared to the 1950 assessment

Hypothesized treated sewage was introducing high nutrients causing growth of cyanobacteria

Risk Analysis

After analyzing many choices, chose new location (freshwater) and greater treatment for sewage to decrease nutrients in effluent

Assessing Environmental ProblemCase Study: Lake Washington

Public Education/Involvement Educated public on why changes were

necessary

Political Action Difficult to organize sewage disposal in so

many municipalities

Changes were not made until 1963!

Evaluation Cyanobacteria slowly decreased until 1975

(gone)

Assessing Environmental ProblemCase Study: Lake Washington

Results

Assessing Environmental ProblemCase Study: Lake Washington