Major themes of environmental Science

1. Human Population

2. Sustainability

3. Global Perspective

4. Urbanization

5. People and Nature

6. Science and Values

• Pop more than doubled in last 40 yrs
• 6.8 bil live today
• by 2050 = 9.4 bil

• Example of Family pop explosion
• Emphasizs a major factor in modern pop explosion
  •   Technology
  • Medicine
  • All Decrease the death rate and increase growth rate

• Famine occurs when human pop exceeds env. resources
• Sahel region of Africa in 1970s
  • 1/2 mill starved
• Emerging global food crisis
  • due to rise in gas = high food cost

• refers to resources and their env.
• sustainable resource harvest
  • same quantity of that resource can be harvested each yr for unlimited amount of time
• Sustainable ecosystem
  • ecosystem that can still maintain its fuctions even when we take things from it

1. Sustainability means for an unspecified long period of time

2. Sustainable growth is an oxymoron

- humans living in harmony w/natural support systems
- an energy policy that doesn't pollute, cause climate change or risk
- provides a share for furture generations
- social, legal, and political system

Carrying Capacity of the Earth

A Global Perspective

- the actions of many groups at many locations affects the eng. of the entire world

-Gaia Hypothesis

*James Lovelock and Lynn Margulis
* Env. has changed by life over the history of life on earth which have helped our chances of cont. life
* The moon doens't look the same b/c there's no life there

Megacities

Precautionary Principle

- Taking precautionary steps to prevent potential harm

**EXAMPLE**:

-1992 Rio Earth SUmmit on Sustainable Development

Placing a Value on the Env.

8 Justifications

1.  Utilitarian
2. Ecological
3. Aesthetic
4. Recreational
5. Inspirational
6. Creative
7. Moral
8. Cultural

Utilitarian

Ecological

Aesthetic

Recreational

Inspirational

Moral

What defines Science

- Scientific understanding of life and its env is based on scientific method

- Sceince is a process

-begins w/ observations

- deals only w/ statements that can be disproved

- When we add #'s to our analysis

*make predictions, analyze strength or relat. & more under.

- Measurements are limited unless accompanied by estimate of its uncertainty

Accuracy and Precision

- Accuracy= what we know(how close to true value a measure is)

- Precision= how well we measure

Dependent Variable

- Responding variable

- Response to change

- Y-axis

Independent Variable

- Manipulated Variable

- Can be Changed

- X-axis

Science- search for understanding

Technology- application of sceintific knowledge that benefits humans

 an increase in output leads to a later decrease

*self-regulating or stabilizing

an increase in output leads to a further increase in the output

*destabilizing

**Env. damage can be especially serious with positive

System Stability

- Has a condition that it remains in unless disturbed

- condition that it returns to if disturbed from it and the cause of the disturbance stops

Exponential Growth

- Growth occurring at a constant rate

**Exponential growth is Positive feedback and is  INCOMPATIBLE with SUSTAINABILITY

Average Residence Time

Biota

Biosphere

- region of Earth where life exists

*also includes the system that sustains life

Ecosystem

- community of organisms and its local nonliving environment in which matter cycles and energy flows

- Can be natural or artificial

Ex:

- Puddle in forest

1. Exponential Growth

2. Lag Time

3. Irreversible Consequences

Three Reasons why Solving Env. Problems is Often Difficult

Exponential Growth

Three Reasons why Solving Env. Problems is Often Difficult

Lag Time

- Time between stimulus and response of a system

-may lead to overshot and collapse

- going beyond the carry capacity can lead to a collapse of a pop

Three Reasons why Solving Env. Problems is Often Difficult

Irreversible Consequences

- Predicted people will have misery in the end b/c of human pop growth
- wrong b/c we didn't all die

-technology saved us

Population

Species

all individuals that are capable of interbreeding

* a species is made up of populations

Population Dynamics

4 General Types of Age Structure Diagrams

1. Pyramid- pop with many young and high death rate (short life)

2. Inverted Pyramid- top heavy

3. Column- Birth rate and death rate are low and a high % of pop is old

4. Column with a buldge- event in the paast caused a high birth or death rate for some age group

History of Human Pop Growth

1. Hunter & gathers- total pop <a few mil

2. rise of agriculture- increase in pop density and inc in human pop

3. industrial rev.- improv. in health & food supply. inc in pop

4. today- rate of growth slow in indust. nations but high in less developed nations

Demographic Transition

Stage 1

- Non industrial country

- Birth rate and death rate high, growth rate low

Demographic Transition

Stage 2

- Period of high growth rate

-w/ industrialization death rate declines but birth rate stays high

Demographic Transition

Stage 3

- Birth rate drops toward death rate

-growth rate decreases

-Will take place if parents come to believe that having a small family is to their benifit

Demographic Transition

-3 stage patterns in birth and death rates

- occured during the process of industrial and economic development of western nations

-leads to decline in pop growth rate

IPAT equation

Impact = population x affluence x technology

Acute or epidemic disease

Chronic disease

5 Unique Properties of water

1. High capacity to absorb and store heat

2.Universal solvent

3. High service tension

4. Solid form is lighter than its liquid form

5. Sunlight penetrates water, permitting photosynthetic organisms to live below surface

Where is water?

97.25% = Ocean

2.05% =  Ice

Also in: Groudwater, lakes, soils, atmosphere, rivers, biosphere

Ogalla Aquifer

Where is it: Great Plains

Importance: About 27 percent of the irrigated land in the United States overlies this aquifer system, which yields about 30 percent of the nation's ground water used for irrigation.

What happend: b/c of irigation the storage has been depleted

Water Pollution

- refers to degradation of water quality

*look at intended use of water

*how far water departs from norm

*its effects on public health

*its ecological impacts

EX: heavy metals, sediments, heat, nitrogen, sodium, phosphorus

Biochemical Oxygen Demand

BOD

- amount of oxygen required for biochemical decomposition

-used in water quality management

*measres the amount of oxygen consumed by microorganisms as they break down organic matter

*routinely measured

*dissolved oxygen content of less than 5 mg/l of water

Fecal Coliform Bacteria

- diff. to monitor disease carring organisms so we use this as a standard measre and indicator of disease

*not allowed any for drinking water and a little for swimming pools

- a proccess by which a body of water develops a high concentration of nutrients

- causes large growth in aquatic plants & photo. bacterica

-bacteria and algae then die

-as they decompose BOD increases

-Oxygen content is sufficiently lower and fish and other organisms may die

Oligotrophic Lake

- Lake w/ relatively low concentration of chemical elements required by life

-clear water

-low abundance of life

Eutrophic Lake

- lake w/high concentration of chemical elements

- often wmats of algae and murky water

- abundance of life

Cultural Eutrophication

(oligiotrophication)

Acid Mine Drainage

- water w/ a high concentration of sulfuric acid that drains from mines

-coal mines often assoc. w/ pyrite

- when it comes into contact w/oxygen & water it weathers

- a product of weathering is sulfuric acid

- water runs through the mine tailings

Surface water Pollution

Point & nonpoint Sources

Point- pollution comes directly from a smokestack, pipe or something that is very clear - these are often easier to identify and mitigate than say

nonpoint- which are more diffuse (agricultural field runoff) and difficult to measure/enforce