Chapter 1 Introducing Environmental Science and Stability Overview

Chapter 1 Introducing Environmental Science and Stability

Overview of Chapter 1 o o o Human Impacts on The Environment Population, Resources and the Environmental Sustainability Environmental Science Assessing Environmental Problems

The Environment (Earth) o o Life has existed on earth for 3. 8 billion years Earth well suited for life • • • o 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 o Earth’s Human Population is over 7 billion • o o Growing exponentially Expected to add several billion more people in 21 st century Increase will adversely affect living conditions in many areas of the world

o What does Where doesthis thesay population about the growth start rate? to stabilize?

Population o Globally, 1 in 5 people lives in extreme poverty • o o 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 o Highly Developed Countries (HDC) • • o 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 o People overpopulation • • o 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 o The average amount of land, water and ocean required to provide that person with all the resources they consume Earth’s Productive Land Water 11. 4 billion hectares Amount Each Person is Allotted (divide 1. 6 hectares Productive Land Water by Human Population) Current Global Ecological Footprint of 2. 3 hectares each person o

Ecological Footprint Comparison

IPAT Model o Measures 3 factors that affect environmental impact (I) Environmental Impact Affluence person I=P A T Number of people Environmental effect of technologies

Environmental Sustainability o o 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 o o Garrett Hardin (1915 -2003) Solving Environmental Problems is result of struggle between: • • o Short term welfare Long term environmental stability and societal welfare Garrett used Common Pastureland in medieval Europe to illustrate the struggle

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

Environmental Science o 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 o System • o Global Earth Systems • o Climate, atmosphere, land, coastal zones, ocean Ecosystem • o A set of components that interact and function as a whole 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 o Most of earth’s systems are in dynamic equilibrium or steady state • o 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 o Variable • • o 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 o 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 o 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 o Five steps are idealistic • o Real life is rarely so neat The following slides illustrate a Case Study using the Five Stages

Assessing Environmental Problem Case Study: Lake Washington o o Large, freshwater pond Suburban sprawl in 1940’s • o 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 o Scientific Assessment • • o 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 o Public Education/Involvement • o Political Action • • o Educated public on why changes were necessary 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 o Results!