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Chapter1.pdf

Environment Tenth Edition

Raven

Chapter 1

Introducing Environmental Science and Sustainability

Introducing Environmental Science and Sustainability

2Copyright ©2018 John Wiley & Sons, Inc.

Overview of Chapter 1

• Human Impacts on The Environment

• Population, Resources and the Environment

• Sustainability

• Environmental Science

• Addressing Environmental Problems

3Copyright ©2018 John Wiley & Sons, Inc.

Food as a Lens for Our Relationship to the Environment

• Chicken sandwich requires: wheat, chicken, other ingredients, pesticides, fertilizers, energy (petroleum) to manufacture, transport, treat generated wastes, and make packaging, landfills

• Our individual choices affect the environment

• How could we adapt our food- production practices for greater sustainability?

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The Environment (Earth)

• Life has existed on Earth for 3.8 billion yrs.

• Earth well suited for life

o Water over 3

4 of planet

o Habitable temperature, moderate sunlight

o Atmosphere provides oxygen and carbon dioxide

o Soil with essential minerals for plants

• Modern humans appeared in Africa only 100,000 years ago

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Increasing Human Numbers

• In 1950, eight cities had populations > 5 million

o NYC -12.3 million

• In 2016, large urban agglomerations of cities o 10 largest metropolitan

areas, total of 200 million

o Tokyo, Japan – 17.8 million, with 38.1 in greater metropolitan area

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Human Population Growth

• In 2017, human population is 7.5 billion:

o Passed 7 billion in 2011

o Growing exponentially

o Estimates of 9.3 -10.5 billion by end of 21st century

• In areas with fast growing populations, quality of life for many people may worsen considerably

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Population and Extreme Poverty

• More than 1 in 2 people live in extreme begin underline poverty end underline o Cannot meet basic needs for food,

clothing, shelter, health

o < $2.50 per U.S. dollars day

• Fertility rates worldwide ~ 3

children per family

o Expected to decline and stabilize by end of 21st century

• Difficult to meet population needs without exploiting Earth’s resources

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Countries Differentiated Based on Wealth

• Highly Developed Countries (HDC)

o Complex industrialized bases, low population growth, high per capita incomes

o Ex: U.S., Canada, Japan

• Less Developed Countries (LDC)

o Developing countries, low level of industrialization, high fertility rate, high infant mortality rate, low per capita income (relative to highly developed countries)

o Ex: Bangladesh, Kenya, and Nicaragua

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Income Disparity Between Rich and Poor

• Rising income disparity in many countries

o Large gap between wealthy and poor citizens

• Differential access to electricity, cars, modern medicine

o Recently, greater disparity between urban and rural citizens in LDC

o Ex: China, India, Brazil, Mexico

• Total wealth of country less accurate in describing well- being of citizens

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Population, Resources, and Environment: Needs for Survival

• Two useful generalizations:

o 1- Essential resources for individual survival are small

• However, rapidly increasing population can quickly overwhelm or deplete, especially locally

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Individual Resource Consumption

• 2- Individual resource consumption can far outweigh needs of survival

o Affluent nations use larger portions and can exhaust resources globally

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Types of Natural Resources

Natural Resources

• Renewable Natural Resources

o Direct solar energy

o Energy of winds, tides, flowing water

o Fertile soil

o Clean air

o Fresh water

o Biological diversity (forests, food crops, fishes)

• Nonrenewable Natural Resources

o Metallic minerals (gold, tin)

o Nonmetallic minerals (salt, phosphates, stone)

o Fossil fuels (coal, oil, natural gas)

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Resource Consumption

• Human use of materials and energy

o Economic and social act

• People in HDCs are big consumers

• Unsustainable Consumption

o When level of demand on resources damages or depletes resources enough to reduce the quality of life for future generations

o Caused by overpopulation and/or overconsumption

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Ecological Footprint

• The average amount of productive land, fresh water, and ocean required to continuously 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 & Water by Human Pop.)

1.5 hectares

Current Average Global Ecological Footprint 2.7 hectares

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Ecological Overshoot

• Humans have a global ecological overshoot

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Ecological Footprint Comparison

• Large variation in footprints among countries

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IPAT Model

• Model - represents a system; describes the system as it exists and predicts how changes in one part of the system will affect the rest of the system.

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Average Fuel efficiency in U.S.

• Average fuel economy

o 22.1 mpg (1988)

o 20.4 mpg (2000)

• SUV popularity

o 24.8 (2015)

• Hybrid popularity

• Passenger car efficiency increased by ~ 50% since 1980 (left)

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Sustainability Requires Long-term Perspective (1 of 2)

• Ability to meet current human economic and social needs without compromising the ability of the environment to support future generations

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Sustainability Requires Long-term Perspective (2 of 2)

Focus on Sustainability

• Stabilize human population

• Prevent pollution where possible

• Restore degraded environments

• Protect natural ecosystems

• Use resources efficiently

• Educate all boys and girls

• Prevent and reduce waste

• Eradicate hunger and poverty

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Sustainability and Human Behavior

• Not often operating sustainably because of behaviors:

o Extract resources as if they are unlimited

o Consume faster than resources are replenished

o Pollute at high rates

o Increase population despite finite resources

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Tragedy of the Commons

• Garrett Hardin (1915–2003)

• Solving environmental problems is result of struggle between:

o Short-term welfare

o Long-term environmental stability and societal welfare

• Common-pool resources

• Garrett used common pastureland in medieval Europe to illustrate the struggle

• Sustainability works best with collaborative stewardship

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Sustainable Development- Systems Concept

• Economic development that meets the needs of the present generation without compromising the ability of future generations to meet their own needs

• Summits helping to form international approaches

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Environmental Science

• Interdisciplinary study of humanity’s relationship with other organisms and the nonliving physical environment

o Biology

o Begin underline Ecology end underline

o Geography

o Chemistry

o Geology

o Physics

o Economics

o Sociology

o Demography

o Politics

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Earth’s System and Environmental Science • System

o A set of components that interact and function as a whole

• Global Earth Systems

o Climate, atmosphere, land, coastal zones, oceans

• Ecosystem

o A natural system consisting of a community of organisms and its physical environment

• Systems in a dynamic equilibrium with feedback among components

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Negative Feedback

• Negative feedback

o Change in some condition triggers a response that counteracts (reverses) the changed condition

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Positive Feedback

• Positive feedback

o Change triggers a response that intensifies the changing condition

o Ex: polar and glacial ice melt, color change leading to more rapid melting

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Science is a Dynamic Process

• Science is a systematic way to investigate the natural world

o To manage and produce information

• Scientists collect objective data through observations and experiments, and make conclusions

• Published work is peer reviewed

o Process by which scientific findings are scrutinized and validated or rejected by other experts in the field

o Helps to self-correct errors

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Scientific Method

• The way a scientist approaches a problem by formulating a hypothesis and then testing it by means of an experiment

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Controls and Variables in Experiments

• Variable

o A factor that influences a process

o May be altered in an experiment to determine its effect on the outcome

• Experimental group

o Chosen variable is altered in known way

• Control group

o Variable is not altered

o Allows for comparison between the tests of when we alter the variable and when we do not alter the variable

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Scientific Knowledge and Theory

• Theory

o An integrated explanation of numerous hypotheses, each supported by a large body of observations and experiments and evaluated by the peer review process

o Simplifies, clarifies, and predicts our understanding of the natural world

• Absolute truth is not possible in science

o Varying degrees of uncertainty

o Knowledge evolves as new evidence is found

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Climate Change: Hypotheses and Theory

• CO2 and other gases from burning fossil fuels affect climate

• Unable to test or run large experiments globally

o Must acquire lots of data and adapt theories and understanding with new data

• Many parts of climate theory are tested

o CO2 and rise in atmosphere

o Impact of gases on solar radiation

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Addressing Environmental Problems

• Five steps represent ideal approach

o Scientific assessment

o Risk analysis

o Public engagement

o Political action

o Long-term evaluation

• Reality is untidy

• Often, public pushes for a solution

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Environmental Science in Practice: Lake Washington • Large, deep freshwater lake

• Suburban sprawl in 1940’s

o 10 new sewage treatment plants dumped treated effluent, high in nutrients, into lake

• Effect = excessive growth of cyanobacteria

o Bacterial decomposition of cyanobacteria depleted O2

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Scientific Assessment of Lake Washington • Scientists from University of Washington studied

problem and collected data

• Study informed Washington Pollution Control Commission (1955) o Commission concluded that effluents added nutrients to

Lake, particularly phosphorus

o Nutrients caused growth of cyanobacteria

o Cyanobacteria decomposed by bacteria depleted O2 o Low O2 reduced fish and small invertebrates

• If pollution stopped, lake would recover

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Recovery Plan for Lake Washington

• Many political hurdles in passing a plan

• Accepted bill was most ambitious and expensive pollution control project in U.S. at the time

o Treated sewage was diverted into trunk sewer that ringed lake (starting in 1963)

o Eventually discharged into Puget Sound, where it would have less effect

o By 1975, lake was healthy and water was clear

o Today, work to reduce waste generation in view of greater population around lake

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Data on Recovery of Lake Washington

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Copyright

Copyright © 2018 John Wiley & Sons, Inc.

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