Semester ReviewSemester Review

Environmental ScienceEnvironmental Science

ObjectivesObjectives Define environmental science and compare

environmental science with ecology and environmentalism.

List five major fields of study that contribute to environmental science.

Distinguish between a renewable resource and a non-renewable resource.

Explain the concept of sustainability and why it is a goal in environmental science.

Explain the concept of an Ecological Footprint

Environmental Science Environmental science is the

study of:– How the natural world works– How the environment affects

humans and vice versa We need to understand our

interactions with the environment– To creatively solve

environmental problems

NYC Today and 400 yrs ago

The Nature of Environmental ScienceThe Nature of Environmental Science

Environment impacts Humans

Its applied goal: solving environmental problems

Solutions are applications of science

An interdisciplinary field Natural sciences: examines the

natural worldEnvironmental science programs

Social sciences: examines values and human behaviorEnvironmental studies programs

Environmental scienceEnvironmental science

Can help us avoid mistakes made by past civilizationsCan help us avoid mistakes made by past civilizations– Human survival depends on how we interact with our Human survival depends on how we interact with our

environment.environment.

– Our impacts are now global.Our impacts are now global.

– Many great civilizations have fallen after depleting their resources.Many great civilizations have fallen after depleting their resources.

The lesson of Easter Island: people annihilated their culture by destroying their environment. Can we act more wisely to conserve our resources?

• Environmental scienceEnvironmental science– Pursues knowledge about Pursues knowledge about

the environment and our the environment and our interactions with itinteractions with it

– Scientists try to remain Scientists try to remain objective and free from biasobjective and free from bias

• EnvironmentalismEnvironmentalism– A social movement A social movement – Tries to protect the natural world Tries to protect the natural world

from human-caused changesfrom human-caused changes

Environmental Science is not Environmental Science is not EnvironmentalismEnvironmentalism

Goals of Environment ScienceGoals of Environment Science

To understand and To understand and solve environmental solve environmental problemsproblems– Ecosystem functions– Air Pollution– Water Pollution– Toxic Chemicals– Climate Change– Resource usage

Ecology is the Foundation of Ecology is the Foundation of Environmental ScienceEnvironmental Science

Ecology: the study the study of how living of how living organisms organisms interact with each interact with each other and their other and their non-living non-living environmentenvironment

Fields of Study that Contribute to Fields of Study that Contribute to Environmental ScienceEnvironmental Science

Biology: Biology: the study of living organismsthe study of living organisms Chemistry: Chemistry: the study chemicals and their the study chemicals and their

interactionsinteractions PhysicsPhysics: the study of matter and energy: the study of matter and energy Earth Science: Earth Science: the study of earth’s nonliving the study of earth’s nonliving

systemssystems Social Sciences: Social Sciences: the study of human the study of human

populationspopulations

We Rely on Natural ResourcesWe Rely on Natural Resources

Natural resources Natural resources = = substances and energy sources needed substances and energy sources needed for survivalfor survival

Renewable natural resourcesRenewable natural resources: can be replenished: can be replenished– Perpetually renewed: sunlight, wind, wave energyPerpetually renewed: sunlight, wind, wave energy– Renew themselves over short periods: timber, water, soilRenew themselves over short periods: timber, water, soil

These can be destroyedThese can be destroyed Nonrenewable natural resourcesNonrenewable natural resources: unavailable after depletion: unavailable after depletion

– Oil, coal, mineralsOil, coal, minerals

Natural ResourcesNatural Resources

Renewable resources like sunlight cannot be depleted.Renewable resources like sunlight cannot be depleted. Nonrenewable resources like oil CAN be depleted.Nonrenewable resources like oil CAN be depleted. Resources like timber and clean water are renewable Resources like timber and clean water are renewable

only if we do not overuse them.only if we do not overuse them.Figure 1.1

Our “Ecological Footprint”Our “Ecological Footprint”

Affluence increases consumptionAffluence increases consumption Ecological footprintEcological footprint: the : the

environmental impact of a environmental impact of a person or populationperson or population– The area of biologically The area of biologically

productive land + water productive land + water – To supply raw resources and To supply raw resources and

dispose/recycle wastedispose/recycle waste People in rich nations have much People in rich nations have much

larger ecological footprintslarger ecological footprints

If everyone consumed the amount of resources the U.S. does, we would need 4.5 Earths!

OvershootOvershoot

We are using renewable resources 30% faster than they We are using renewable resources 30% faster than they are being replenishedare being replenished

Humans have surpassed the Earth’s capacity to support us

Population & ConsumptionPopulation & Consumption

Population growth amplifies all human impactsPopulation growth amplifies all human impacts– The growth rate has slowed, but we still add more than The growth rate has slowed, but we still add more than

200,000 people to the planet each day200,000 people to the planet each day Resource consumption has risen faster than populationResource consumption has risen faster than population

– Life has become more pleasantLife has become more pleasant– Rising consumption also amplifies our demands on the Rising consumption also amplifies our demands on the

environment environment The 20 wealthiest nations have 55 times the income of The 20 wealthiest nations have 55 times the income of

the 20 poorest nationsthe 20 poorest nations– Three times the gap that existed 40 years agoThree times the gap that existed 40 years ago

Ecological Footprints are not EqualEcological Footprints are not Equal

Not everyone benefits Not everyone benefits equally from rising affluenceequally from rising affluence

The ecological footprints of The ecological footprints of countries vary greatlycountries vary greatly– The U.S. footprint is much The U.S. footprint is much

greater than the world’s greater than the world’s averageaverage

In the U.S. the richest 1%In the U.S. the richest 1%– Have 25% of all incomeHave 25% of all income

Sustainability is the Goal!Sustainability is the Goal!

Condition in which Condition in which human needs are met human needs are met without harming without harming future generations. future generations.

We are not living We are not living sustainably today.sustainably today.

What needs to What needs to change?change?

Sustainability and the Future of our WorldSustainability and the Future of our World Sustainability: we must live within our planet’s means

– So the Earth and its resources can sustain us and all life for the future

Sustainability involves conserving resources– Developing long-term solutions– Keeping fully functioning ecosystems

Natural capital: Earth’s total wealth of resources– We are withdrawing it faster that it’s being replenished– We must live off Earth’s natural interest (replenishable

resources), not its natural capital

Sustainable SolutionsSustainable Solutions

Sustainable developmentSustainable development– using resources to satisfy current needs without using resources to satisfy current needs without

compromising future availability of resourcescompromising future availability of resourcesSustainability involvesSustainability involves

– Renewable energy sourcesRenewable energy sources– Soil conservation, high-efficiency irrigation, organic Soil conservation, high-efficiency irrigation, organic

agricultureagriculture– Pollution reductionPollution reduction– Habitat and species protectionHabitat and species protection– RecyclingRecycling– Fighting global climate changeFighting global climate change

Humanity’s challenge is to develop solutions that further our quality of life while protecting and restoring the environment.

Will we develop Will we develop in a sustainable way?in a sustainable way?

This is the single most important question we face.

ObjectivesObjectives Understand the Nature of Science Understand how scientific inquiry and technological

design, including mathematical analysis, can be used to pose questions, seek answers, and develop solutions.

Describe and Apply the Scientific Process Describe how humanity altered the environmental

– Hunter-gatherers– Agricultural revolution– Industrial revolution

The Nature of ScienceThe Nature of Science

ScienceScience: a systematic process for learning about the : a systematic process for learning about the world and testing our understanding of itworld and testing our understanding of it– The accumulated body of knowledge arising from the The accumulated body of knowledge arising from the

dynamic process of observation, testing, and discoverydynamic process of observation, testing, and discovery Civilization depends on science and technologyCivilization depends on science and technology

– Science tries to understand the world and steer a safe courseScience tries to understand the world and steer a safe course Science is essential to sort fact from fiction Science is essential to sort fact from fiction

– Develop solutions to the problems we faceDevelop solutions to the problems we face– It must be accessible and understandable to the publicIt must be accessible and understandable to the public

Science Asks and Answers Science Asks and Answers QuestionsQuestions

It is an incremental approach to the truthIt is an incremental approach to the truth Scientists do not simply accept conventional wisdomScientists do not simply accept conventional wisdom

– They judge ideas by the strength of their evidenceThey judge ideas by the strength of their evidence Observational (descriptive) scienceObservational (descriptive) science: information is gathered : information is gathered

about organisms, systems, processes, etc.about organisms, systems, processes, etc. Cannot be manipulated by experimentsCannot be manipulated by experiments Phenomena are observed and measuredPhenomena are observed and measured Used in astronomy, paleontology, taxonomy, genomicsUsed in astronomy, paleontology, taxonomy, genomics

Hypothesis-driven scienceHypothesis-driven science: targeted research : targeted research Experiments test hypotheses using the scientific methodExperiments test hypotheses using the scientific method

The Scientific Method: The Scientific Method: A Traditional ApproachA Traditional Approach

Science tests ideasScience tests ideas– Scientists in different fields approach problems Scientists in different fields approach problems

differentlydifferently Assumptions:Assumptions:

– The universe works according to unchanging The universe works according to unchanging natural laws natural laws

– Events arise from causes, and cause other Events arise from causes, and cause other eventsevents

– We use senses and reason to understand We use senses and reason to understand natural processesnatural processes

Applications of ScienceApplications of Science

Policy decisions and Policy decisions and management practices management practices are applications of science.are applications of science.

Prescribed burning, used Prescribed burning, used to restore forest to restore forest ecosystems altered by ecosystems altered by human suppression of fire.human suppression of fire.

Figure 1.8a

Applications of ScienceApplications of Science

Technology is another Technology is another application of science.application of science.

Energy-efficient Energy-efficient methanol-powered methanol-powered fuel cell car from fuel cell car from DaimlerChryslerDaimlerChrysler

Figure 1.8b

Scientific Method: AssumptionsScientific Method: Assumptions

Fixed natural laws govern how the universe worksFixed natural laws govern how the universe works All events arise from causes, and cause other eventsAll events arise from causes, and cause other events We can use our senses and reason to detect and We can use our senses and reason to detect and

describe nature’s lawsdescribe nature’s laws

Scientific MethodScientific Method A step-by-step method for testing A step-by-step method for testing

ideas with observations.ideas with observations.

Scientists use educated guesses Scientists use educated guesses called called hypotheseshypotheses to generate to generate predictionspredictions

hypotheses are tested hypotheses are tested experimentally.experimentally.

Results may reject or support a Results may reject or support a hypothesis.hypothesis.

Results never Results never prove prove a hypothesis, a hypothesis, but only lend support to it by but only lend support to it by failing to reject it.failing to reject it.

Figure 1.9

Scientific ProcessScientific Process

Peer review, Peer review, publication, and publication, and debate are parts debate are parts of the larger of the larger scientific process.scientific process.

Figure 1.11

Hypothesis, Theory, and Hypothesis, Theory, and ParadigmParadigm

HypothesisHypothesis = an educated guess, to be tested = an educated guess, to be tested TheoryTheory = a well-tested and widely accepted = a well-tested and widely accepted

explanation, validated by much previous researchexplanation, validated by much previous research ParadigmParadigm = a dominant view. May shift if new = a dominant view. May shift if new

results show old results or assumptions to be results show old results or assumptions to be wrongwrong

Experiments Test the Validity of a HypothesisExperiments Test the Validity of a Hypothesis

Variable: a condition that can change Independent variable: is manipulated Dependent variable: is measured and depends on

the independent variable Controlled experiment: the effects of all variables

are controlled– Except the independent variable whose effect is being

tested Control: an un-manipulated point of comparison Quantitative data: uses numbers Qualitative data: does not use numbers

Hypotheses are Tested in Different WaysHypotheses are Tested in Different WaysManipulative experimentsManipulative experiments• Yield the strongest evidenceYield the strongest evidence• Reveals causal relationshipsReveals causal relationships• Lots of things can’t be Lots of things can’t be

manipulatedmanipulated

Natural tests • Results are not neat and

clean• Show real-world complexity• Answers aren’t black and

white

Human Impact Over Earth’s HistoryHuman Impact Over Earth’s History Wherever humans Wherever humans

have hunted, have hunted, grown food, or grown food, or settled we have settled we have changed the changed the environment.environment.

How have those How have those

changes impacted changes impacted the environment the environment over human over human history?history?

Hunter-Hunter-GatherersGatherers

Most of human historyMost of human history Obtained food by moving Obtained food by moving

around collecting plants around collecting plants and hunting wild animals. and hunting wild animals.

Affected the environment:Affected the environment:– Set fires to drive game Set fires to drive game

during huntingduring hunting– Spread plant species as they Spread plant species as they

moved from place to placemoved from place to place– May have led to the May have led to the

disappearance of many large disappearance of many large mammal species such as mammal species such as ground sloths, giant bison, ground sloths, giant bison, mastodons, cave bears, and mastodons, cave bears, and saber-tooth catssaber-tooth cats

Agricultural Agricultural RevolutionRevolution

Plants and animals were Plants and animals were domesticated and domesticated and population grewpopulation grew

10,000 years ago10,000 years ago Life got easierLife got easier Settlements began Settlements began

formingforming Impact on environment Impact on environment

grewgrew Habitat destroyedHabitat destroyed Artificial selection of Artificial selection of

domesticated cropsdomesticated crops Farmland replaced forestFarmland replaced forest

Industrial Industrial RevolutionRevolution

There was a shift to fossil There was a shift to fossil fuels as an energy sourcefuels as an energy source

Mid-1700sMid-1700s Life got easierLife got easier Advances in technologyAdvances in technology Healthcare and sanitation Healthcare and sanitation

improvedimproved People lived longerPeople lived longer People moved to cities People moved to cities

away from farmsaway from farms Increased environmental Increased environmental

impact.impact.

Thomas Malthus and human populationThomas Malthus and human population

• Thomas MalthusThomas Malthus• Population growth must be Population growth must be

controlled, or it will outstrip food controlled, or it will outstrip food

production.production.• Starvation, war, diseaseStarvation, war, disease

• Neo-MalthusiansNeo-Malthusians• Population growth has disastrous effects.Population growth has disastrous effects.• Paul and Anne Ehrlich, Paul and Anne Ehrlich, The Population BombThe Population Bomb (1968) (1968)

• Agricultural advances have only postponed crises.Agricultural advances have only postponed crises.

Human Population Levels Human Population Levels Throughout HistoryThroughout History

Loss of BiodiversityLoss of Biodiversity

BiodiversityBiodiversity: the number : the number and variety of species and variety of species that live in an areathat live in an area

Why is loss of Why is loss of biodiversity a bad thing?biodiversity a bad thing?– Higher biodiversity = Higher biodiversity =

healthier ecosystemhealthier ecosystem– Organisms are considered Organisms are considered

a natural resourcea natural resource

We face challenges in biodiversityWe face challenges in biodiversity

• BiodiversityBiodiversity: the cumulative : the cumulative number and diversity of number and diversity of living thingsliving things

• Human actions have driven Human actions have driven many species extinctmany species extinct– Biodiversity is declining Biodiversity is declining

dramaticallydramatically– We are setting in motion a We are setting in motion a

mass extinction eventmass extinction event

Biodiversity loss may be our biggest problem; once a species is extinct, it is gone forever