Transcript Fundamental Concepts

Chapter 1
FUNDAMENTAL CONCEPTS
Earth
Earth formed from a solar nebula: 4.6 Ga
 Life on Earth began: 3.5 Ga
 Geology: Science of processes related to:
 Composition, structure, history and life of Earth
 Environmental Geology:
 Studies entire spectrum of human interactions with
the physical environment
 It is geology applied to:
 Solve conflicts in land use
 Minimize environmental degradation
 Maximize the benefits of natural resources

Earth History
Inception:
4.6 Ga

Change
over time:
Environment
and
bioextinction
Figure 1.A
Fig. 10.9
The geologic column
The composite stratigraphic
column was assembled from
incomplete sections found in
different places across the
globe. By correlation, the
strata in the different
columns can be stacked in a
sequence that spans almost
all of Earth history.
Earth is Unique

No other planet in the solar system currently
has the right chemical and physical mix needed
to support life

No conclusive evidence of life existing
elsewhere in the universe has yet been
discovered as far as we know

Its size, gravity, magnetic field, water, distance
to the Sun, are perfect!
What Do Geologists Do?

Seek to understand all processes that operate on and inside the
Earth

Study:




Our planet’s long history
Water bodies (rivers and lakes)
Hazardous processes such as earthquakes, volcanic eruptions, flood,
and landslides
Rocks/minerals
Earth Environment (1)
 James
Hutton (1785): Earth as a
superorganism
 James
Lovelock: Gaia hypothesis
 Earth is an organism
 Life significantly affects the Earth’s
environment
 Life modifies the environment for the
betterment of life
 Life deliberately or consciously controls
the global environment
Earth Environment (2)
 Earth:

Dynamic, alive, and complex
 Everything

alive:
With a beginning and an end
 Earth
environment as a total, as a whole
 Prolong


Earth’s sustainable healthy life
Environment monitoring
Environment problems
 mapping and analysis
 prevention and protection
Environmental Sciences
 Environment: A complex
system with physical,
biological, geological, ecological, and geopolitical
aspects
 Requires
multidisciplinary research:
Environmental geology, environmental chemistry,
global climate change, biological diversity and
ecosystems, environmental economics,
environmental ethics, environmental law, etc.
 Environmental
crisis: Population, environmental
hazards, resource limitations and contaminations,
environment ownership (both in space and time)
Why environmental geology?
 Earth:
Source for habitats and resources
 There
is a geologic aspect in every environmental
condition
 Environmental



geology: Applied geology
To better understand environmental problems
Geologic knowledge for problem solving
Optimize the use of resources to maximize
environmental benefits for the society
Environmental Geology Involves Study of:

Earth Materials (rocks, minerals, soils)


formation, effects on health, as resource or waste
Natural Hazards

floods, landslides, quakes, volcanic eruptions


Land for Site Selection


Land use planning, environmental Impact analysis
Hydrologic Processes of surface/ground water


minimize loss of life
Water resources, pollution
Global Geologic Process

Atmospheric, hydrologic, and lithospheric
Landslide is a red flag for future urban development
Concepts of Environmental Science
1.
Human Population Growth

2.
Environmental impact = (individual impact X population)
Sustainability

This is an objective. Ensure that future generations have equal
opportunity to the planet’s resources

Limitation of Resources
3.
Concept of Earth having system/subsystems
4.
5.
Hazardous Earth Processes
Scientific knowledge and values
6.
Other concepts:


Uniformitarianism
Our obligation to the future
Concerns of Environmental Geology

Pollution (air, water, soil) due to garbage disposal,
farming, and fuel burning

Water supplies (Earth population grows by more
than 100 M each year). Important for desert cities

Disposal of radioactive waste

Effect of other hazardous waste (chemicals like
pesticide) on air, groundwater, and soil

Waste from mining activity (coal, metal ores)
Concerns of Environmental Geology

Geologic hazards (geohazards):
Earth processes harmful to humans and their property, e.g.,
earthquake, volcanic eruption, flooding, slides

Coastline erosion

Sea level rise due to global warming (risk for coastal cities)

Acid rain (due to fuel burning; e.g. S-bearing coal burning)

Ozone depletion; global warming
CO2 Levels are Increasing
Acid Rain
increasing
because of
burning coal
and other
fossil fuels
Ozone
Depleting
because
of man
made
chemicals
Mean Temperature is Rising
because of higher CO2 levels
Figure 1. Grinnell Glacier in
Glacier National Park,
Montana; photograph by Carl
H. Key, USGS, in 1981. The
glacier has been retreating
rapidly since the early 1900's.
The arrows point to the former
extent of the glacier in 1850,
1937, and 1968.
The worldwide shrinkage of
mountain glaciers is thought to
be caused by a combination of a
temperature increase from the
Little Ice Age, which ended in
the latter half of the 19th
century, and increased
greenhouse-gas emissions.
Sea Level is Rising
Population growing exponentially
Exponential Growth Rate

The population growth is defined by:
Pt = Po ert
Pt is the population at a given time t
Po is the original population
r is the growth rate (per time; t-1 or 1/t)
t is time (t)
e is the base of the natural log (i.e., ln) function (e1=2.718)



Unit of P is # (i.e., number of) of people because:
(# of people) = (# of people) e (1/t)(t)
The rate (i.e., slope) of growth (i.e., people/time) of the
population increases with time (i.e., is not constant)
In simple math the eqn. for exponential growth is:
Pt/Po=100.3n
where n is the umber of doubling times
Start with 0 people. Assume that after a year each
person has to babies. What is the rate of growth?
Year
(t)
Population (Pt)
Rate of growth

0
po=1
0
1
pt=2
1
2
pt=4
2
3
pt=8
4
4
pt=16
8
Starting at an arbitrary time, the population is:
 2 times (i.e., 21) as large after each doubling time tD
 4 times (i.e., 22) as large after 2 doubling times, 2tD
 8 times (i.e., 23) as large after 3 tD
Population
Number of doubling times (tD) passed
1 = 20 = Po
0
2 = 21 = P t
1
In general: Pt = Po2n = Po 100.3n
4 = 22 = P t
2
where n = tD
8 = 23 = P t
3
Given the ratio of Pt = Po we can find tD
2tD = Pt
n
Given Po and doubling time, we can find Pt
 Exponential growth occurs by an excess of births over death
 As the absolute number of people increases, the number of people
added each year will increase also, yielding a concave upward curve
Overpopulation is number one environmental problem!
Population “time bomb”: because of exponential growth
 Earth’s carrying capacity is limited:


More resources used, more land space occupied, more waste produced!
Assuming exponential growth

Growth rate (r): is measured as %/yr

Doubling time (tD) is a function of growth rate (r): tD =70/r
Examples:
 If the growth rate r is 0.5%/yr, what is the doubling time (tD)
assuming exponential growth: tD = 70/0.5 = 140 year

If inflation is 8%/yr, how long does it take for the cost of living to
double?
tD = 70/8 = 9 yr
Example 1 - Simple Math
If the ratio of U.S. population in year 2090 (i.e., Pt) to that of
1850 (i.e., Po) is 16, find:
 How many doubling times have passed (i.e., n)
 Duration of each doubling time
 % per year increase of the population (i.e., growth rate)
Pt = Po 2n = Po 100.3n
Pt/Po = 100.3n
16 = 100.3n Now take logarithm of both sides:
log16 = 0.3n log10
(Note: log10 = 1)
log24 = 0.3n
(Note: logxn = nlogx)
4log2 = 0.3n
n = 1.2/0.3 = 4 doubling times
2090-1850 = 240 years
240/4 = 60 (duration of each doubling time in years)
tD = 60 = 70/%r
% growth rate = 1.17 (i.e., per year increase)
Example 2
If the population of a country doubles its size each 40 years (i.e., tD
= 40), and if the population in 1980 is 10x10 6 heads (i.e., Po),
calculate the:
 population in the year 2100 (i.e., Pt)
 % per year increase of the population (growth rate per year)
Pt = Po2n =Po 100.3n
Pt/Po = 100.3n
Time period: 2100-1980 = 120 years
n = 120/40 = 3
Pt = Po 2n = Po 23 = Po 100.3(3)
Pt = Po 100.9
Pt = 10x106 (100.9)
log Pt = log10 + 6log10 + 0.9log 10
log Pt = 1 + 6 + 0.9 = 7.9
(population in the year 2100)
Pt = 107.9
tD = 0.693/r  40 = 70/%
 growth rate per year: % = 1.75
Overpopulation

Human Population Growth


Overpopulation



Rate of growth increased due to better:
agriculture, sanitation, medicine, energy sources
Started few centuries ago
Is a global problem
Population Grows Exponentially
Exponential human population growth
Scenario:
A student
starts a job
with 1 cent for
the first day.
Salary is
doubled each
day for 31
days!
At the end of
the month, the
student is a
multimillionaire!
Growth of World’s Population



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
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





World’s population was ~ 300 M about 2 ka
It apparently didn't increase much up to AD 1000
It reached 800 million by the beginning of the Industrial Revolution
in 1750
Average growth rate=0.13%/yr in 750 yrs (1000-1750)
By 1800, population reached one billion while the second billion
was reached by 1930 (i.e., in 130 yrs)
Average growth rate = 0.53%/yr
From 1930 to 1960, population reached 3 billion (in 30 yrs)
Average growth rate = 1.36 %/yr
By 1974, the fourth billion was reached (in 14 yrs)
Average growth rate = 2.1% from 1960 to 1974
From 1974 to 1990, the mark hit five billion (in 16 yrs)
Average growth rate slowed to 1.4%
World annual
population
increase peaked
in the late 1990s
Uneven growing pace and global distribution
 Little
access to, or use of, modern family
planning methods in less developed countries
 Africa:
Home to a larger share of world
population over next half century
 Asia:

Many nations overpopulated
India, over one third of its population under
15 years old, is likely the largest population
by mid century
Population
Bomb:
About to
Explode?
Effect of Population on Earth Resources

Degradation of the environment by pollution
 Pollution: Unfavorable alteration of our
surroundings, wholly or largely as a byproduct of human action

Serious shortages of resources (including food)
 Is brought by straining Earth’s ability to
provide food, clothing, shelter, and energy

e.g., on the average, each of us, on a yearly
basis, uses: 500 kg steel, 25 kg Al, 200 kg salt
Effect of Population on Earth Resources

Development of Geologic Problems
 As homes replace fields in flat areas, farming
is displaced to hilly regions
 Steeper slopes accelerate soil loss, polluting
streams with sand and silt

An increased rate of injuries, property damage,
and loss of life (due to geologic hazards)
Humans are affecting the Earth system:

Burning petroleum and coal, which increases the
greenhouse effect

Intensive farming activities, which have an
impact on soil, ground and surface water

Production and release of gases containing
chlorine, which destroys ozone

Redistribution of water through the construction
of giant reservoirs, which changes the
distribution of weight at Earth’s surface and
alters, slightly but measurably, the rotation of the
Earth on its axis
Human Influences …

Our daily activities are having measurable effects
on:
 Rainfall
 Climate
 Air
 Water quality
 Erosion
 Mineral resources
 In North America, we use 20 tons of mineral
resources per person/year
Sustainability
Is an environmental objective!
 Goal to ensure that future generations have equal
access to Earth resources


Is a long-term objective, achieved over decades or
centuries

Requires types of development that:
 Are economically viable
 Do no harm the environment
 Are socially just
Facts about Sustainability

An evolving concept

Expectation and reality

Criteria variations in space and over time

Long-term implications

Requiring careful resources allocation, largescale development of new tech for resource use,
recycling, and waste disposal
Logging – clear-cut timber harvesting exposes soil, leading to erosion
Sustainability of Resources

Possible for the renewable resources such as air,
water, fish, forest, domesticated stock and
wildlife, agricultural products

For non-renewable resources, such as fossil fuels
and minerals, sustainability is possible by:

Conservation/Recycling to extend their
availability

Finding substitution (alternative) for the
material
System Concept

A system is any portion of the universe
that can be isolated from the rest of the
universe for observing and measuring
change

The simplest kind to understand is an
isolated system
 the boundary completely prevents the
exchange of either matter or energy
Open and Closed Systems

The nearest thing to an isolated system
in the real world is a closed system:
 exchanges energy with its
surroundings, but not matter

An open system can exchange both
energy and matter across its boundary
Systems
Earth system

Energy and materials (like water, carbon, and
minerals) are transferred from one system to
another

To a close approximation, Earth is a closed
system because:
 Meteorites do come in from space and fall on
Earth
 A tiny trickle of gases leaves the atmosphere
and escapes into space

Earth is comprised of four open systems
Our Planet’s “Four Spheres” or
Subsystems (cryosphere is the fifth)

The atmosphere:


The hydrosphere:


Oceans, lakes, streams, underground water, snow,
and ice
The biosphere:


Nitrogen, oxygen, argon, carbon dioxide, and water
vapor
All of Earth’s organisms, as well as any organic
matter not yet decomposed
The geosphere:

The solid Earth from core to surface, composed
principally of rock and regolith
.
Earth’s Systems and Changes
 Earth: A dynamic
system
 Two
engines behind its dynamics:
 Internal and external heat sources
 Five
interconnected subsystems:
lithosphere, atmosphere, hydrosphere, and
biosphere, cryosphere


these subsystems mutually adjust
Energy Sources
Short-term
changes: Longlasting adverse
effects.
Ducktown, TN
due to mining,
~ 100 yrs
Earth’s Systems and Changes
Global Environmental Problems

Deforestation

Soil erosion

Water and air pollution

Desertification

Pollution due to mining (minerals, coal, oil)

Overuse of groundwater and surface water
resources (e.g., Aral Sea)
Dying Aral Sea
surrounded by
salt flats, due to
diversion of
water for
agriculture
System Approach

The whole Earth behaves like an organism

It is a self-regulating network of interdependent physical
and biological systems

A disturbance (e.g., deforestation) in one part of the system
(Earth) must result in adjustment in other parts (e.g., global
warming)
Earth’s Systems and Changes (2)
 System
conditions: Open vs. closed systems
 System
input-output analysis
 System
changes: Types of changes, rates of
changes, scales of changes, etc.
 Rates
of change: Average residence time

T = S/F
(T: residence time, S: total size of stock,
F: average rate of transfer)
Environment influenced by three
inter-related variables
1.
Earth:
 rocks and minerals
 origin, variety, distribution, and pollution of soil
 causes of, distribution, and prediction of
earthquake/volcanic activity
 cause and prevention of coastal erosion and
slope failure
 mineral and water resources
Environment influenced by three
inter-related variables
2.



Air:
composition and circulation
pollution by human activities
climate
Environment influenced by three
inter-related variables
3.





Water:
distribution
movement and flooding
range in chemical composition
pollution by human activities
management
Inter-relationship of atmosphere,
hydrosphere, & lithosphere
H2O circulates freely among the:

atmosphere (as gas, e.g., vapor)

ground surface (as solid, e.g., ice, and
liquid water)

subsurface (liquid water)
Solid surface material are:

carried to the ocean by runoff (as
suspended, dissolved, and bed loads)

carried to the atmosphere by wind (as
dust)
Cyclical Movements

The movement of materials is continuous

There are two key aspects to cycles:
 The reservoirs in which the materials
reside
 The flows, or fluxes, of materials from
reservoir to reservoir

The speed of movement differs greatly in
different cycles
Three Most Important Cycles
The hydrologic cycle
 Water in Earth’s hydrosphere
 The rock cycle
 Rock is formed, modified, decomposed,
and reformed by the internal and external
processes of Earth
 The tectonic cycle
 Movements of plates of lithosphere, and
the internal processes of Earth’s deep
interior that drive plate motions

The hydrologic cycle

Is powered by heat from the sun

Encompasses the movement of
water in the atmosphere, in the
hydrosphere, on the Earth’s surface,
and in the Earth’s crust
Rock Cycle
Rock is any naturally formed, nonliving, firm
and coherent aggregate of mineral matter that
constitutes part of a planet.
 The three rock families:
 Igneous rock:
 Created through the cooling and solidification
of magma
 Sedimentary rock:
 Formed from deposits of sediment
 Metamorphic rock:
 Formed by the effects of pressure and heat on
existing rocks

Tectonic Cycle

Tectonics is the study of the movement and
deformation of the lithosphere

When magma rises from deep in the mantle, it
forms new oceanic crust at mid ocean ridges

The lifetime of oceanic crust is shorter than
the lifetime of continental crust

The most ancient oceanic crust of the ocean basins is
only about 180 million years old, and the average
age of all oceanic crust is about 70 million years old



When all oceanic crust sinks back into the
mantle, it carries some water with it
The water is driven off during volcanic
eruptions
Some constituents in the hot rock (calcium,
magnesium) are the same as those of seawater
Tectonic Cycle
Other cycles

The other cycles include the
biogeochemical cycles:
 Carbon
 Oxygen
 Nitrogen
CO2 Cycle
Predicting Future Changes

Uniformitarianism

The present is the key to the past

The present is the key to the future

Changes of frequency and magnitude:
Geological processes and human activities

Environmental unity: Chain of actions and reactions

Earth system

Gaia hypothesis: Earth is a living organism

Complex and interrelated subsystems

Global perspective on environment
Hazardous Earth Processes
Hazardous Earth processes and risk statistics for
the past two decades
 Annual loss of life: About 150,000
 Financial loss: > $20 billion
 More life loss from a major natural disaster in a
developing country (2003 Iran quake, ~300,000
people)
 More property damage occurs in a more
developed country
Risk Assessment
 Hazard
identification
 Risk




assessment (types, probability, and
consequences of impact)
Critical facility mapping and analysis
Economic impact analysis
Societal impact analysis
Total environmental impact analysis
 Risk
management and mitigation
Risk Perception
 Public
attitude toward risks
 Public


acceptance for risks
Threshold for living with dangers
Planning decisions, e.g., floodplain
development, waste disposal
 Public


awareness and collective actions
Anticipatory measures
Mitigation planning
Scientific Knowledge and Values (2)
 3-D
environmental problems
 Changes
of environment in the 4-D (time)

Expansiveness of geologic time

Broad spectrum of geologic processes

Great variations in rates of geologic
processes
 Humans


are super agent of change
Holocene epoch
Industrialization and global environmental
changes
Scientific
Knowledge
and Values (1)
Figure 1.12
Science and Solution
 Science: Accumulated
 Knowledge:
knowledge
Basis for decision making
 Scientific
methods: Formulate possible
solutions to environmental problems
 Scientific
design: Structure more suitable for
certain environmental settings
 Scientific
info: Public awareness and
environmental regulations
Applied and Critical Thinking Topics
 Do
you think the Earth is a living organism? Why
or why not?
 Why
did you take this environmental geology
course?
 Would
an exponential negative growth of human
population be a solution to many environmental
problems?
 Science
can certainly provide solutions to
environmental problems, but think of ways that
science brought about environmental problems.