An Introduction to Environmental Science This lecture will help you understand

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  • Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings
  • An Introduction to Environmental Science

This lecture will help you understand:

  • The meaning of the term environment
  • The importance of natural resources
  • That environmental science is interdisciplinary
  • The scientific method and how science operates
  • Some pressures facing the global environment
  • Sustainability and sustainable development

Environment: the total of our surroundings

  • All the things around us with which we interact:
    • Living things
      • Animals, plants, forests, fungi, etc.
    • Nonliving things
      • Continents, oceans, clouds, soil, rocks
    • Our built environment
      • Buildings, human-created living centers
    • Social relationships and institutions

Humans and the world around us

  • Humans change the environment, often in ways not fully understood
  • We depend completely on the environment for survival
    • Increased wealth, health, mobility, leisure time
    • But, natural systems have been degraded
      • i.e., pollution, erosion and species extinction
    • Environmental changes threaten long-term health and survival
  • Environmental science is the study of:

Natural resources: vital to human survival

  • Renewable resources:
    • Perpetually available: sunlight, wind, wave energy
    • Renew themselves over short periods: timber, water, soil
      • These can be destroyed
  • Nonrenewable resources: can be depleted
    • Oil, coal, minerals
  • Natural resources = substances and energy sources needed for survival

Global human population growth

  • More than 6.7 billion humans
  • Why so many humans?
    • Agricultural revolution
    • 10,000 years ago
      • Stable food supplies
    • Industrial revolution
    • mid-1700’s
      • Urbanized society powered by fossil fuels
      • Sanitation and medicines
      • More food

Mid Class Questions

  • How can the increase in population over the past 10,000 year affect our Environment in relation to out natural resources?

Thomas Malthus and human population

  • Thomas Malthus (1766-1834)
  • An Essay on the Principal of Population
  • (1798)
    • Population growth must be restricted, or it will outstrip food production
    • Starvation, war, disease
  • Neo-Malthusians

Garrett Hardin’s Tragedy of the Commons

  • Unregulated exploitation leads to resource depletion
    • Soil, air, water
  • Resource users are tempted to increase use until the resource is gone
  • Solution?
    • Private ownership?
    • Voluntary organization to enforce responsible use?
    • Governmental regulations?

Tragedy of the Commons


Environmental science

  • … can help us avoid mistakes made by past civilizations.

Easter Island “The Mirror of our Fate


  • Describe what happened on Easter Island.
  • Why did the population collapse? What evidence do we have to support the conclusions concerning the fate of Easter Island?
  • In a paragraph write a reaction to the essay. Do you think Easter Island can be or should be considered a “Mirror of our Fate”.
  • The lesson of Easter Island: people annihilated their culture by destroying their environment. Can we act more wisely to conserve our resources?

Environmental science: how does the natural world work?

  • Environment  impacts  Humans
  • It has an applied goal: developing solutions to environmental problems
  • An interdisciplinary field
    • Natural sciences: information about the world
      • Environmental Science programs
    • Social sciences: values and human behavior
      • Environmental Studies programs

What is an “environmental problem”?

    • The perception of what constitutes a problem varies between individuals and societies
    • Ex.: DDT, a pesticide
      • In developing countries: welcome because it kills malaria-carrying mosquitoes
      • In developed countries: not welcome, due to health risks

Environmental Problems

  • What are some local environmental that exist locally?
  • What caused these problems?
  • What can we do to fix these problems?

Environmental science is not environmentalism

  • Environmental science
    • The pursuit of knowledge about the natural world
    • Scientists try to remain objective
  • Environmentalism
    • A social movement dedicated to protecting the natural world

The nature of science

  • Science:
    • A systematic process for learning about the world and testing our understanding of it
    • A dynamic process of observation, testing, and discovery
    • The accumulated body of knowledge that results from this process
  • Science is essential
    • To sort fact from fiction
    • Develop solutions to the problems we face

The Demon Haunted World: Science as a Candle in the Dark Carl Sagan (1995)

  • We’ve arranged a global civilization in which the most crucial elements-transportation, communications, and all other industries; agriculture, medicine, education, entertainment, protecting the environment; and even the key democratic institution of voting-profoundly depend on science and technology. We have also arranged this so that almost no one understands science and technology. This is a prescription for disaster. We might get away with it for a while, but sooner or later this combustible mixture of ignorance and power is going to blow up in or faces…Science is an attempt, largely successful, to understand the world, to get a grip on things, to get hold of ourselves, to steer a safe course.

Applications of science

  • Policy decisions and management practices
  • Energy-efficient methanol-powered fuel cell car from DaimlerChrysler
  • Technology

The scientific method

  • A technique for testing ideas with observations
  • Assumptions:
    • The universe works according to unchanging natural laws
    • Events arise from causes, and cause other events
    • We use our senses and reason to understand nature’s laws

The scientific method

  • A scientist makes an observation and asks questions of some phenomenon
  • The scientist formulates a hypothesis, a statement that attempts to explain the scientific question.
  • The hypothesis is used to generate predictions, which are specific statements that can be directly and unequivocally tested.
  • The test results either support or reject the hypothesis

Experiments test the validity of a hypothesis

  • Manipulative/Controlled experiments yield the strongest evidence
  • 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
    • But, lots of things can’t be manipulated
  • © 2008 John Wiley and Sons Publishers
  • Can the scientific method me used in our daily life?
  • What examples can you come up with?
  • What are the independent and dependent varibles?

The scientific process is part of a larger process

  • The scientific process includes peer review, publication, and debate
  • A consistently supported hypothesis becomes a theory, a well-tested and widely accepted explanation
  • With enough data, a paradigm shift a change in the dominant view can occur

Population & consumption

  • Human population growth exacerbates all environmental problems
    • The growth rate has slowed, but we still add more than 200,000 people to the planet each day
  • Our consumption of resources has risen even faster than our population growth.
    • Life has become more pleasant for us so far
    • However, rising consumption amplifies the demands we make on our environment.

The “ecological footprint” Mathis Wackernagel & William Rees (1990s)

  • The environmental impact of a person or population
    • Amount of biologically productive land + water
    • for raw materials and to dispose/recycle waste
  • Overshoot: humans have surpassed the Earth’s capacity…or have they???
  • We are using 30% more of the planet’s resources than are available on a sustainable basis!

Ecological footprints are not all equal

  • The ecological footprints of countries vary greatly
    • The U.S. footprint is almost 5 times greater than the world’s average
    • Developing countries have much smaller footprints than developed countries
  • What happens if we continue to overshoot?
  • Can we reduce our environmental impact?
  • Is there anything we can do so that we do not have to reduce our environmental impact?
  • Can corporations help us achieve either the 2nd or 3rd questions?

We face challenges in agriculture

  • Expanded food production led to increased population and consumption
  • It’s one of humanity’s greatest achievements, but at an enormous environmental cost
    • Nearly half of the planet’s land surface is used for agriculture

We face challenges in pollution

  • Waste products and artificial chemicals used in farms, industries, and households
  • Each year, millions of people die from pollution

We face challenges in climate

  • Scientists have firmly concluded that humans are changing the composition of the atmosphere
  • The Earth’s surface is warming
    • Melting glaciers
    • Rising sea levels
    • Impacted wildlife and crops
    • Increasingly destructive weather
  • Since the Industrial Revolution, atmospheric carbon dioxide concentrations have risen by 37%, to the highest level in 650,000 years

We face challenges in biodiversity

  • Human actions have driven many species extinct, and biodiversity is declining dramatically
    • We are at the onset of a mass extinction event
  • Biodiversity loss may be our biggest environmental problem; once a species is extinct, it is gone forever

The Millennium Ecosystem Assessment 2005 included 2000 world’s leading environmental scientists from 100 countries

  • The most comprehensive scientific assessment of the condition of the world’s ecological systems
  • Major findings:
    • Humans have drastically altered ecosystems
    • These changes have contributed to human well-being and economic development, but at a cost
    • Environmental degradation could get much worse
    • Degradation can be reversed, but it requires work

Our energy choices will affect our future

  • The lives we live today are due to fossil fuels
      • Machines
      • Chemicals
      • Transportation
      • Products
    • Fossil fuels are a one-time bonanza; supplies will certainly decline
    • We have used up ½ of the world’s oil supplies; how will we handle this imminent fossil fuel shortage?

Sustainable solutions exist

  • We must develop solutions that protect both our quality of life and the environment
  • Organic agriculture
  • Technology
    • Reduces pollution
  • Biodiversity
    • Protect species
  • Waste disposal
    • Recycling
  • Alternative fuels

Are things getting better or worse?

  • Many people think environmental conditions are better
    • Cornucopians: Human ingenuity will solve any problem
  • Some think things are much worse in the world
    • Cassandras: predict doom and disaster
  • How can you decide who is correct?
    • Are the impacts limited to humans, or are other organisms or systems involved?
    • Are the proponents thinking in the long or short term?
    • Are they considering all costs and benefits?

Sustainability: a goal for the future

  • How can humans live within the planet’s means?
    • Humans cannot exist without functioning natural systems
  • Sustainability
  • Sustainable development: the use of resources to satisfy current needs without compromising future availability of resources


  • Environmental science helps us understand our relationship with the environment and informs our attempts to solve and prevent problems.
  • Identifying a problem is the first step in solving it
  • Solving environmental problems can move us towards health, longevity, peace and prosperity
    • Environmental science can help us find balanced solutions to environmental problems


  • The term “environment” includes
    • Animals and plants
    • Oceans and rivers
    • Soil and atmosphere
    • All of the above are included in this term


  • Which of the following is correct about the term “environmentalism”?
    • It is very science-oriented
    • It is a social movement to protect the environment
    • It usually does not include advocacy for the environment
    • It involves scientists trying to solve environmental problems


  • What is the definition of “sustainable development”?
    • Using resources to benefit future generations, even if it means lower availability now
    • Letting future generations figure out their own problems
    • Using resources to satisfy current needs without compromising future availability
    • Letting each country decide what is its best interest

QUESTION: Weighing the Issues

  • Which do you think is the best way to protect commonly owned resources (i.e., air, water, fisheries)?
    • Sell the resource to a private entity
    • Voluntary organizations to enforce responsible use
    • Governmental regulations
    • Do nothing and see what happens

QUESTION: Weighing the Issues

  • Do you think the rest of the world can have an ecological footprint as large as the footprint of the United States?
    • Yes, because we will find new technologies and resources
    • Yes, because the footprint of the United States is not really that large
    • Definitely not; the world does not have that many resources
    • It does not matter; it’s not that important

QUESTION: Interpreting Graphs and Data

  • According to this graph, what has happened to the population over the last 500 years?
  • a) It has grown exponentially
  • b) It has grown linearly
  • c) It has decreased
  • d) It has slowed down recently

QUESTION: Interpreting Graphs and Data

  • What happens if test results reject a hypothesis?
  • The scientist formulates a new hypothesis
  • It shows the test failed
  • The hypothesis was supported
  • The predictions may not have been correct

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