Geology: Study of earth contents, i.e., rocks, mineral, etc.

Environmental Geology: Branch of geology which deals with Human & Earth Environment

It involves our daily lives:

- Raw materials for material goods
- Water for drinking, washing, etc.
- Soil for growing our food
- Ground on which we & others stand
- Our homes and associated problems
- Stable? Landslides, Land-subsidence
- Disaster: Floods, earthquakes, etc.

APPROACH TO ENVIRONMENTAL GEOLOGY:

- Uses the science of geology to solve problems resulting from interaction between five systems:
- Solid earth, life, water, ice, air

Env. Geology uses many branches of traditional geology:

- Mineralogy & economic geology: (minerals)
- Petrology: (analysis of rocks)
- Engineering geology (building of structures on land)
- Sedimentology: (Origin and interpretation of sediments)
- Structural geology: ( how rocks deform)
- Geophysics & geochemistry ( physics & chemistry of the earth)
- Hydrology (study of water)

(Read:  Figure 1.1, page 4 (old book)

HOW DO WE STUDY ENV. GEOLOGY

- Involves collection of geologic data from : (a) Surface (rock outcrops)(b) Subsurface (from boreholes)

Started in the US in 1950s
Problems were observed that needed answers
 Example: Population growth rate increased rapidly
    & therefore, increased demand for resources.

City Planners (main engineers) forces to recognized geologists who could produce:

ð Multipurpose Maps that showed areas of:

- Unstable ground
- Prone to earthquakes
- High flood potential
- Water of good/poor quality
- Mineral resources

(Very useful in solving env. Problems by 1992, etc.)

Government then voted $184 in 4 years for more.

SOME CAUSES OF ENV. PROBLEMS:

1. High rate of World Population Growth

ð Good living standard of life.
*But Planet has limited supply of air, land, water, mineral resources

ð Carrying Capacity:  Idea that a given amount of resources can support a limited number of people/animals/plants
ð Env. Studies have a lot to do with estimating population (population dynamics)

POPULATION GROWTH RATE (PGR)
 

PGR = Birth Rate (BR) – Death Rate (DR)

 PGR = BR – DR

BR and DR are expressed in no. of births or deaths per 1000 people per year.

e.g.   Birth Rate = 20
         Death Rate = 10
         PGR = ?

PGR = 10
i.e., 10/1000/yr

Population Doubling Time: (PDT)

- Time for a population to double

PDT = 70/ Growth rate (%) in years
  (Rule of 70.)

Quiz:

1.   If growth rate = 10, find PDT.
    (70 years)

2. If growth rate = 20, find PDT.
(35 years)

3.   If PDT = 17.5 years, find growth rate.
    (40 years)

17.5 = ( 70 / GR ) ¸ GR %
GR = 70/17.5 = 4 %

THEORIES OF OVERPOPULATION

1. Overpopulation Scenario One:

(“The sky is falling.”)
ð The earth is at OR close to its carrying capacity.
ð How???
Due to the fact that catastrophic events (extinction) involved one species per 25 years in
the Cretaceous Period (many million years ago).

But in 1991, 1700 species went into extinction!

Thus, Earth is coming to an end, and cannot sustain 9-10 billion people projected for the year 2050.
An agreement against “Sky is Falling”.

ð Prediction of population today can be more precisely done than in the past (Cretaceous).

2 Overpopulation Scenario Two:
  (“The Gaia Hypothesis.”)

 
- Gaia (Greek goddess of the earth)
- Proposed by: James Love Lock (British Scientist)
:  Lynn Margulis (US Biologist)
ð Stated that the earth is a “SUPER ORGANISM” whose evironment is controlled by plants and
animals that inhabit it.
ð Earth is “Self-adjusting”, and has a balance in its components

PLAN: Toward a SUSTAINABLE ENVIRONMENT

i.e., an environment that satisfies its needs without jeopardizing the need of future generations.

- Regulate our food, fuel, air, water, resources for the interest of future generations.

PROBLEM: We know what needs to be done, BUT DON’T WANT OR KNOW HOW TO DO IT??

What to REGULATE???

1. Population Growth (Birth Rate):

- US, Western Europe are approaching REPLACEMENT REPRODUCTION – rate at which babies are produced just to replace PARENTS.
ð Countries are controlling attitude toward fertility: India, Bangladesh, Indonesia, Egypt, China
(Nigeria 15 ???)

2. Energy and Global Warming:

ð A serious environmental problem from increase in CO2 in the air.
- Caused by burning of Gas, Coal, Oil
ð Should regulate all these to prevent catastrophic events in the future!!!

Number of people supported by earth is limited by amount of useful land for agriculture

ð Soil quality is deteriorating
ð Need to control soil fertility by adding
(Chemical and biochemical fertilizers)

e.g. China, Southeast Asia

4. Forests:
 

- Deforestation is a big environmental problem caused by:
a. Clearing soil for agricultural purposes – Brazil
b. Logging for wood, especially in Tropics – Thailand
c. Demand for wood fuel and forest products – India, West Africa

5. Resources:

- Our current society is a “THROW-AWAY” society
ð Must RECYCLE some of our products

a. Our resources are dwindling
b. Most disposed waste constitute environmental problem
- paper, plastic, glass, aluminum, steel (mainly)

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