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Ch 1 An Introduction to Environmental Science Part 1: Foundations of Environmental Science PowerPoint® Slides prepared by Jay Withgott and Heidi Marcum Copyright © 2008 Pearson Education, Inc., publishing as Benjamin Cummings 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 Gaia Hypothesis The belief that Earth has it’s own lifecycle Elephants kill trees Volcano’s erupt Lightning causes fires Global warming and cooling happened before without humans The actions of many groups of people at many locations affects the environment of the entire world. (CFC’s) Gaia hypothesis James Lovelock and Lynn Margulis Life affects the environment at a global level Environment: the total of our surroundings • All the things around us with which we interact: • Living things - biotic • • Nonliving things – abiotic (Natural) • • Animals, plants, forests, fungi, etc. Continents, oceans, clouds, soil, rocks, wind Our built environment (Man-made) • Buildings, human-created living centers, roads, transportation Humans and the world around us Humans change the environment, often in ways not fully understood. Ex. Pest Control, weed killers 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: How the natural world works How the environment affects humans and vice versa Ecology – The study of the environment Natural resources: vital to human survival Natural resources = substances and energy sources needed for 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 (May be renewable???) Oil, coal, minerals (not in our lifetime) Sustainability and Carrying Capacity What is the maximum number of people the Earth can sustain? Currently we are using resources unsustainably. (30%) Faster than they can be replenished. Carrying capacity = the maximum number of individuals of a species that can be sustained by an environment w/o decreasing the capacity of the environment to sustain that same amount in the future Sustainability Sustainability refers to resources and their environment. Sustainable resource harvest Same quantity of that resource can be harvested each year for an unlimited amount of time. (Trees – Silviculture) Sustainable ecosystem An ecosystem from which we are harvesting a resource that is still able to maintain its essential functions/properties. (Forest) Sustainable Global Economy To achieve we must Develop an effective population-control strategy.(Controversial… legal? Terra Nova) Completely restructure our energy programs. (Big Oil??) Institute economic planning that will encourage pop control and wise use of resources. Implement social, legal, political and educational change. Terra Nova Policy? Moving Toward Sustainability The new paradigm Evolutionary rather than revolutionary. Inclusive, not exclusive. Proactive, not reactive. Attracting, not attacking. Assisting the disadvantage, not taking advantage. Global human population growth More than 7 billion humans Why so many humans? Agricultural revolution Stable food supplies Industrial revolution Urbanized society powered by fossil fuels Sanitation medicines More food and Thomas Malthus and human population • Thomas Malthus Population growth must be restricted, or it will outstrip food production • Starvation, war, disease • Predator-prey relationships • Neo-Malthusians • Population growth has disastrous effects • Paul and Anne Ehrlich, The Population Bomb (1968) • 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? The “ecological footprint” 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 We are using 30% more of the planet’s resources than are available on a sustainable basis! Population Graphs Exponential growth Logistic Graph / S-Curve Overpopulation Birth Rate Mortality Rate Total Population Population Density Immigration Emigration Catastrophic Ecents Rule of 70 AKA Doubling time Doubling time = 70/ Growth Rate (PGR) PGR = Net Gain (NG)/ total population NG = Birth Rate – Death Rate + immigration- emigration Classic Example = 7% growth rate – double time = 10 years Homework for Thursday Pick 2 countries Find birth rate, death rate, total population Find 2 other countries with a positive growth rate Find 1 country with a negative growth rate Find 10 megacities (populations of 8 million +) Environmental science … can help us avoid mistakes made by past civilizations. The lesson of Easter Island: people annihilated their culture by destroying their environment. Can we act more wisely to conserve our resources? Easter Island Named from Dutch Sailors who landed on Easter Sunday http://www.gns.cri.nz/Home/Our-Science/Environment- Climate/Environmental-Change/Research/Easter-Islandcollapse Definitions Limiting factors - things that prevent a population from growing any larger. Disease, food supply, natural factors, humans, predation, nutrients Biotic Potential - An estimate of the maximum capacity of living things to survive and reproduce under optimal environmental conditions. Continues forever. S-Curve - Labels Exponential growth, transitional phase (lag time), Plateau phase, carrying capacity, maximum sustainable yield Precautionary Principle 1992 - Rio Earth Summit on Sustainable Development Defined PP – when there is a great threat of serious environmental damage we should not wait for scientific proof before taking precautionary steps to prevent potential harm. Precautionary Principle PP is a proactive, rather than a reactive, tool. Adopted by the city of SF and the European Union Placing a Value on the Environment The value of the environment based on 8 justifications Utilitarian Ecological Aesthetic Recreational -- Inspirational Creative Moral Cultural Placing a Value on the Environment Utilitarian- the environment has value because it benefits individuals economically or is necessary for human survival. Ecological- ecosystem is necessary for survival of some species of interest or that the system itself provides benefit. Placing a Value on the Environment Aesthetic- has to do with our appreciation of the beauty of nature. Recreational- viewing organisms in a natural setting. Inspirational- to benefit the inner self Creative- aid to human creativity Placing a Value on the Environment Moral- the belief that various aspects of the environment have the right to exist and it is our obligation to allow them to continue. End of lecture day 1 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 Applications of science Policy decisions and management practices Technology Energy-efficient methanolpowered fuel cell car from DaimlerChrysler Restoration of forest ecosystems altered by human suppression of fire 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 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 Types of Data Data are recorded observations or items of information Data fall into two categories Qualitative, or descriptions rather than measurements Quantitative, or recorded measurements, which are sometimes organized into tables and graphs Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Induction in Discovery Science Inductive reasoning draws conclusions through a limited set of observations Repeat specific observations can lead to important generalizations For example, “the sun always rises in the east” Deductive reasoning draws conclusions from initial definitions and assumptions by means of logical reasoning (transitive property of equality) Mr. Daly is a human Humans are mortal Mr. Daly is mortal Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Role of Hypotheses in Inquiry A hypothesis is a tentative answer to a well-framed question (If-Then statement) A scientific hypothesis leads to predictions that can be tested by observation or experimentation Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings A Closer Look at Hypotheses in Scientific Inquiry A hypothesis must be testable and falsifiable Hypothesis-based science often makes use of two or more alternative hypotheses Failure to falsify a hypothesis does not prove that hypothesis For example, you replace your flashlight bulb, and it now works; this supports the hypothesis that your bulb was burnt out, but does not prove it (perhaps the first bulb was inserted incorrectly) Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Designing Controlled Experiments A controlled experiment compares an experimental group (the artificial kingsnakes) with a control group (the artificial brown snakes) Ideally, only the variable of interest (the color pattern of the artificial snakes) differs between the control and experimental groups A controlled experiment means that control groups are used to cancel the effects of unwanted variables A controlled experiment does not mean that all unwanted variables are kept constant Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Limitations of Science In science, observations and experimental results must be repeatable Science cannot support or falsify supernatural explanations, which are outside the bounds of science Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Theories in Science In the context of science, a theory is: Broader in scope than a hypothesis General, and can lead to new testable hypotheses Supported by a large body of evidence in comparison to a hypothesis Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Model Building in Science Models are representations of natural phenomena and can take the form of: Diagrams Three-dimensional objects Computer programs Mathematical equations Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The Culture of Science Most scientists work in teams, which often include graduate and undergraduate students Good communication is important in order to share results through seminars, publications, and websites Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings Science, Technology, and Society The goal of science is to understand natural phenomena The goal of technology is to apply scientific knowledge for some specific purpose Science and technology are interdependent Biology is marked by “discoveries,” while technology is marked by “inventions” Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings The combination of science and technology has dramatic effects on society For example, the discovery of DNA by James Watson and Francis Crick allowed for advances in DNA technology such as testing for hereditary diseases Ethical issues can arise from new technology, but have as much to do with politics, economics, and cultural values as with science and technology Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings 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 Millennium Ecosystem Assessment 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 Leaves future generations with a rich and full Earth Conserves the Earth’s natural resources Maintains fully functioning ecological systems Sustainable development: the use of resources to satisfy current needs without compromising future availability of resources Conclusion 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 QUESTION: Review Which of the following is correct about the term “environmentalism”? a) b) c) d) 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 QUESTION: Review Adding various amounts of fertilizer to plants in a laboratory is a _____ type of experiment a) b) c) d) Correlative Natural Manipulative Rare QUESTION: Review What is the definition of “sustainable development”? a) b) c) d) 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)? a) b) c) d) 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? a) b) c) d) 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? a) The scientist formulates a new hypothesis b) It shows the test failed c) The hypothesis was supported d) The predictions may not have been correct