chapter 1 environmental science and sustainability...ecology scientific study of interactions among...
TRANSCRIPT
Chapter 1 Environmental Science and Sustainability
Overview
Human Impacts on the Environment
Population, Resources and the Environment
Environmental Sustainability
Environmental Science
Addressing Environmental Problems
Ecology
Scientific study of interactions among organisms and their environment
Environmental science is interdisciplinary Biology
Ecology
Geography
Chemistry
Geology
Physics
Economics
Sociology
Politics
The Environment (Earth)
Earth is 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
Life has existed on earth for ~3.8 billion years
Humans are altering the planet’s natural
systems
Human Impact on the Environment
Satellite view of North America at night
Human Impacts on Environment — Population
Human population is over 7 billion people Growing
exponentially
Human Impacts on Environment — Population
Population
1 in 4 people live in extreme poverty Cannot meet basic needs for
food, water, 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
Gap Between Rich and Poor
Islamabad, Pakistan
Philippines
Mumbai, India
Pennsylvania
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 (~7.1 billion)
1.6 hectares
Current Global Ecological Footprint of each person
2.7 hectares!
Ecological Footprint Comparison
How is this
possible?
Ecological Footprint Comparison
Most of the human population has a relatively small ecological footprint (i.e. they are economically poor)
Technologies allow us to “borrow” resources for short term gains (this is not sustainable)
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
IPAT Model
Panning for gold
Hydraulic mining for gold
Effects of technology
vs.
IPAT Model
Plow and ox Diesel tractor
Effects of technology
vs.
IPAT Model
Native American spear fishing Commercial trawler
Effects of technology
vs.
IPAT Model
Logging with axes Industrial logging
Effects of technology
vs.
http://www.youtube.com/watch?v=yIRE9cBTYuI
Types of Natural Resources
Tragedy of the Commons
Garrett Hardin (1915-2003)
The “commons” (pasture land) in medieval Europe illustrates the demand on public resources
Solving environmental problems is the result of balancing: Short term welfare
Long term environmental stability and societal welfare
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
Sustainable Development Economic development that meets the needs of
the present generation without compromising future generations
Dubai’s “Sustainable City” to be completed in 2016
Environmental Sustainability
Science
From the Latin “scientia” meaning “knowledge”
An effort to understand how the universe works through the Scientific Method Observable evidence Thought Experimentation
Builds on previous knowledge Is the earth round?
Scientific Method
Controls and Variables in Experiments
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
Addressing Environmental Problems
Textbook case study: Lake Washington
Assessing Environmental Problem Case 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
Assessing Environmental Problem Case Study: Lake Washington
Cyanobacteria (blue-green algae) bloom
Assessing Environmental Problem Case Study: Lake Washington
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 Problem Case Study: Lake Washington
Public Education and 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 Problem Case Study: Lake Washington
Monitoring Results
Assessing Environmental Problem Case Study: Lake Washington
Lake Washington today