Chapter 1-Studying the State of Our Earth

APESUnit I: Sustainability

Objectives1. 1. Define the field of environmental science and

discuss its importance2. Identify ways in which humans have altered and

continue to alter our environment3. Describe key environmental indicators that help us

evaluate the health of our planet4. Define sustainability and explain how it can be

measured using the ecological footprint5. Explain how the scientific method is used to study

environmental problems6. Describe some of the unique challenges and

limitations of environmental science.

I. Studying the environmentEnvironmental Studies:

Case Study: the mysterious Neuse River Fish Killer (Pfiesteria)

1)Human activities can affect environment in complex and unexpected ways

2)Environmental science can be controversial3)Findings are not always as clear cut as they

appear to be

Environmental IndicatorsHow are planet’s life support services being degraded

by human induced changes?Ecosystem Services: The processes by which life

supporting resources are producedEnvironmental Indicators: describe current state of an

enviro systemSustainability: living in such a way that resource use

does not deprive future generations of that resource; finding alternatives and protecting capacity of environment to continue to supply resources; The capacity to endure

Stewardship: management of resources to ensure the ability of future generations to; the ability of the earth’s natural systems to adapt to changing environmental conditions into the very long-term future.

Three principles of sustainability

1) Reliance on solar energy: warms the planet, provides energy for photosynthesis, powers indirect forms of solar energy such as wind and flowing water. 2) Biodiversity: variety of organisms, natural systems in which they exist and interact, the services these organisms provide, and the ability to adapt to changing environmental conditions.3) Chemical cycling: circulation of chemicals from environment-organism-environment

ResourcesExamples: defined by how quickly we can use them up or

how well nature can replenish them after we use them.Perpetual: Supply continuous; cannot be depleted on a human time scale. SolarPotentially renewable: takes several days to several hundred years to be replenished through natural processes. Soil, forests, freshwater, fish populations, fresh air. Highest rate at which they can be used is sustainable yield. Non-Renewable: Exist in a fixed quantity in earth’s crust; exhaustible. Geologic processes create these resources on a time scale of millions to billions of years. Fossil fuels, metallic mineral resources, non-metallic mineral resources.

 

II. Measuring Human Impact on the EnvironmentEcological Footprint: amount of biologically

productive land and water needed to provide the people in a particular country or area with an indefinite supply of renewable resources and to absorb and recycle wastes and pollution associated with resource use.

World Wildlife Fund (WWF) estimated that global ecol footprint exceeded earth’s biological capacity by 30%; we need 1.3 planets

William Rees and Mathis Wakernagel (developers of footprint model) estimate it would take 5 more planet Earths for the rest of the world to reach current U. S. levels of renewable resource consumption.

I = P x A x TIn most less-developed countries key

factors are population and degradation of resources

In more-developed countries it is over consumption

Ecological Footprint: a measure of how much a person consumes, expressed in are of land (often hectares/person or number of planets

Developed vs. Developing Countries

Fig. 1-14, p. 20

Tragedy of the Commons: Overexploiting Shared Renewable Resources

Private property: individuals or companies own rights to land, minerals or other resources

Common property: rights to certain resources are held by large groups or individuals

Open-access renewable resources: owned by no one and available for use by anyone at little or no charge.

Garrett Hardin 1968 outlined the misuse of open-access resources

Solutions: 1) use resource at a rate well below sustainable yield or 2) convert to private ownership

Living in an Exponential Age

Linear Vs. Exponential GrowthLinear-Quantity

increases by a constant amount per unit of time. Ex. 1,2,3,4,5

Exponential-Quantity increases by a fixed percent of whole in a given time-increase is proportional to what is already there.

Doubling time and the Rule of 70.

To find doubling time of a quantity growing at a given annual percentage rate, divide percentage into 70.Examples:

• $100 invested at a rate of 5% = doubling time

70/ 5% = 20 year double time• Population of 1 million growing at a rate of 3% =

___ DT70/ 3% = 23.3

To get annual growth rate, divide 70 by doubling time

• Oil consumption doubles every 50 years = rate of growth

70/50-1.4%

Percent Change Percent Change-increase or decrease-can be calculated using the following formula:

Change in Quantity X 100% Original QuantityExample: You consumed 800 gallons of gas in 2006 and 1200 gallons in 2007. What is the percent of increase in your gasoline consumption?

If gasoline is $3.00/gallon how much more did you spend on gas?

Example: A deer population goes from 1000-3000- what is the percent change?

1200$13$400 gal

gal

%501005.800/4001200800 X

%2001001000/200030001000 X

Scientific Notation and Dimensional Analysis

The study of Environmental Science involves analysis of data, and making conclusions about environmental impact based on calculations with that data. You will NOT be allowed to use calculators on unit problems, tests, or the national exam and should practice using scientific notation and utilizing dimensional analysis to convert units.

Example: Your car gets 20 mpg and you drive 40,000 miles. How many gallons of gas have you burned?

4 x 104 miles 1 gallon = 4 x 104 = 2 x 103 gallons 2.0 x 101 miles 2 x 101

OR 2000 gallons

III. The Scientific MethodExperimental Design: Experimental Group,

Control Group, Variables, Sample Size, Repeated Trials

Null Hypothesis: a statement or idea that can be falsified, or proven wrong

Inductive Reasoning: making general statements from specific facts or examples.

Deductive Reasoning: applying a general statement to specific facts or situations

HHMI: Changing Planet: Past, Present, Future-Lecture 4/Chapter 15

http://media.hhmi.org/hl/12Lect4.html

Environmental Science Presents Unique ChallengesLack of baseline data

Subjectivity

Interactions

Human Well-Being