Chapter 1 Introducing Environmental Science and Stability

Overview of Chapter 1 Human Impacts on The Environment Population, Resources and the Environment Environmental Sustainability Environmental Science Assessing 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 Impacts on Environment- Population Earth’s Human Population is over 7 billion Growing exponentially Expected to add several billion more people in 21st century Increase will adversely affect living conditions in many areas of the world

What does this say about the growth rate? Where does the population growth start to stabilize?

Population Globally, 1 in 5 people lives in extreme poverty Cannot meet basic need for food, clothing, shelter, health Difficult to meet population needs without exploiting earth’s resources $2/day

Gap Between Rich and Poor Highly Developed Countries (HDC) Complex industrialized bases, low population growth, high per capita incomes Ex: US, Canada, Japan, England 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 Consumption 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 Mathis Wackernagel 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) 1.6 hectares Current Global Ecological Footprint of each person 2.3 hectares

Ecological Footprint Comparison

Environmental effect of technologies 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 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 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 Global Earth Systems Ecosystem 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 us understand how human activities effect 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 Change in 1 part of system leads to change in another Negative feedback- change triggers a response that counteracts the changed condition Positive feedback- change triggers a response that intensifies the changing condition

Scientific Method

Controls and Variables in Experiment 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 change with new information

Inductive and 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 Real life is rarely so neat The following slides illustrate a Case Study using the Five Stages

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 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/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 Results!