lecture 2_population growth and broader perspective_final
TRANSCRIPT
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
1/41
EnvironmentalGeology
Dr Amanda DiochonDepartment of Geology
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
2/41
Learning Outcomes (Part I)
Describe the Earth as a system, our roleand effectsExplain the concept of exponentialpopulation growth in the context ofgeologic hazards and resource
consumptionDefine sustainability in terms of humanimpact on the biosphere
1-2
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
3/41
Earth as a System
Constantly changingand evolvingPrinciple ofenvironmental unityNeed to understandEarth from systemsperspective
Makes us goodstewards
1-3
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
4/41
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
5/41
Learning Outcomes (Part I)
Describe the Earth as a system, our roleand effectsExplain the concept of exponentialpopulation growth in the context ofgeologic hazards and resource
consumptionDefine sustainability in terms of humanimpact on the biosphere
1-5
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
6/41
Population Growth
Linear Added, straight line
Slow and steady
(Non-linear)Exponential
Multiplied, nonlinearIncreases greatly overtime
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
7/41
Population Growth and DoublingTime
Growth rate of 1%would suggest adoubling time of 100years (1% per year x100 yrs = 100%)
rule of 70 is a betterapproximation:
Population doubling time= 70 / growth rate (%)
So 2% growth rate =35 yr doubling time
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
8/41
Doubling time & growth rate
Doubling time Growth rate
World 43 yrs 1.6% per yearN America 50 yrs 1.4% per yearS America 41 yrs 1.7% per year
Africa 26 yrs 2.8% per year
Asia 43 yrs 1.6% per yearEurope 346 yrs 0.2% per yearOceania 43 yrs 1.5% per year
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
9/41
Global Population Growth
~ 200, 000 years 1billion peopleDoubled in 100 years(2 billion)Doubled again in 45years (4 billion)
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
10/41
Limits to Growth?
Antoni van Leeuwenhoek (1687): upperlimit of 13.4 billionThomas Malthus (1798)
Population growth exponential, foodproduction linear
Food production controls populationCarrying capacity (1970s): finiteresources and computer models
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
11/41
IPAT Equation
I=P+A+TI=impact
P=population A=affluenceT=technology
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
12/41
Discussion Question
Can the exponential growth modelaccurately reflect the impact of populationgrowth on the planets resources andenvironmental health? Explain youropinion using at least one example
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
13/41
Learning Outcomes (Part I)
Describe the Earth as a system, our roleand effectsExplain the concept of exponentialpopulation growth in the context ofgeologic hazards and resource
consumptionDefine sustainability in terms of humanimpact on the biosphere
1-13
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
14/41
Sustainability
Being able to maintain a system orprocess for an indefinite period of timeSustainable society
Lives within the Earths capacity to provideresources for future generations
Natural systems operate this way
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
15/41
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
16/41
Ecological Footprint
Biologically productive land/sea areaneeded to support lifestyle of humansCertain portion of the biosphere forextracting resources and absorbing waste
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
17/41
Human Impact and
ConservationDuring the Cretaceous, the extinction rateaveraged one species per 25 years. In 1991more than 1,700 species became extinct asa result of human activity.
Are we exceeding the limits of what theearth can support ?
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
18/41
Easter Island
Dutch sailors (1722) 2000 inhabitants
Windswept, grasscovered wasteland No trees or native
animals 200 statues with 700 in
various stages ofdevelopment (>80tons, 10 km)
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
19/41
Easter Island
Developed 400-700 AD 7 000-20 000 people
during peakconstruction
Palm trees and nativeflora 30 000 years prior
Abundant naturalresources
Dolphins, birds, nuts,timber
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
20/41
What Happened?
800 AD charcoal1400 AD palms
extinctNo birds or dolphinsin diet after 1500 ADDeforestation andecosystem services
Food and watershortages
Collapse
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
21/41
Small scale example of current
society? Not just aboutcaring. . .need afundamental
understanding ofhow the worldworks
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
22/41
What could or should be doneto remedy the environmental
problems associated with such alarge human population?
1-22
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
23/41
Learning Outcomes (Part I)
Describe the Earth as a system, our roleand effects
Explain the concept of exponentialpopulation growth in the context ofgeologic hazards and resource
consumptionDefine sustainability in terms of humanimpact on the biosphere
1-23
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
24/41
Learning Outcomes (Part II)
Describe our solar system and the size ofthe Earth relative to the solar system,
galaxy and universeUnderstand how the nebular hypothesisexplains the formation of the solar system
and the orbital characteristics of theplanets and moons
1-24
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
25/41
Space?
Astronomicenvironment has
huge influence on theEarth systemSuns energy Moons gravitational
fieldOther planets
1-25
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
26/41
2-26
The Solar System
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
27/41
The Solar System
1-27
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
28/41
The Sun
Average starNuclear fusion ofhydrogen and heliumto produce energyHot dense centersurrounded by anouter, less denseatmosphereReleaseselectromagneticradiation
2-28
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
29/41
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
30/41
2-30
Pluto
Demoted as a planet in 2006
Rocky, cold and small
Very far away, last in solar system
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
31/41
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
32/41
2-32
The Moon
Earths only satellite Gravity controlstides
Important for coastalprocesses
Gravity alsominimizes thewobble of the Earth
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
33/41
Learning Outcomes (Part II)
Describe our solar system and the size ofthe Earth relative to the solar system,
galaxy and universeUnderstand how the nebular hypothesisexplains the formation of the solar system
and the orbital characteristics of theplanets and moons
1-33
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
34/41
Solar System: Observations
Formed around 4.6 billion years ago(common origin of bodies)Planets revolve around Sun incounterclockwise direction and haveregular, circular orbitsSun and most planets (except Venus) spin
on their axes in a counterclockwisedirection; Moons same
All planets and moons lie in a solar plane1-34
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
35/41
2-35
Nebular Hypothesis
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
36/41
Nebular Hypothesis and Our
Moon
1-36
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
37/41
How Reliable is NebularHypothesis?
Most bodies rotate andrevolve counter-clockwise
All bodies in same plane withsolar equatorMost craters occurred earlyin the solar systems historySolidification around sametime
Accretion disks have beenfound around other stars(see photo)
2-37
New stars forming in the gas and cloudsof the Eagle Nebula as seen from the
Hubble space telescope
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
38/41
Other Stars in
the UniverseOur galaxy is theMilky Way
Most bright points inthe night sky aregalaxiesThe Big Bang Theoryexplains how theuniverse was formedfrom a centralexplosion
2-38
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
39/41
Other Stars in the Universe
2-39
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
40/41
Learning Outcomes (Part II)
Describe our solar system and the size ofthe Earth relative to the solar system,
galaxy and universeUnderstand how the nebular hypothesisexplains the formation of the solar system
and the orbital characteristics of theplanets and moons
1-40
-
8/14/2019 Lecture 2_Population Growth and Broader Perspective_final
41/41
Next Class
Finish Up Earth from a Larger PerspectiveStart Earth MaterialsWritten assignment 1 due at the beginningof class