1. Introduction to Environmental Science
In every deliberation, we must consider our impact on the next seven generations.
- The Iroqouis Confederacy

2. What Is Environmental Science?
Environmental science is the study of the air, water, and land surrounding an organism or a community, which ranges from a small area to Earth’s entire biosphere.
It includes the study of the impact of humans on the environment.

3. What is the Goal of Environmental Science?
A major goal of environmental science is to understand and solve environmental problems.
To accomplish this goal, environmental scientists study two main types of interactions between humans and their environment:
How our actions alter our environment.
The use of natural resources like water, coal, and oil.

4. Our Environment through Time
Wherever humans have hunted, grown food, or settled, they have changed the environment.
For example, the environmental change that occurred on Manhattan Island over the last 300 years was immense, yet that period was just a “blink” in human history.

5. Manhattan Island-1624 and today

6. First Impact: Hunter-Gatherers
Hunter-gatherers are people who obtain food by collecting plants and by hunting wild animals or scavenging their remains.
Hunter-gatherers affect their environment in many ways:
Native American tribes hunted buffalo.
The tribes also set fires to burn prairies and prevent the grow of trees. This left the prairie as an open grassland ideal for hunting bison.

7. First Impact: Hunter-Gatherers
In North America, a combination of rapid climate changes and overhunting by hunter-gatherers may have led to the disappearance of some large mammal species, including:
giant sloths
giant bison
mastodons
cave bears
saber-toothed cats

8. The Agricultural Revolution
Agriculture is the raising of crops and livestock for food or for other products that are useful to humans.
The practice of agriculture started in many different parts of the world over 10,000 years ago.
The change had such a dramatic impact on human societies and their environment that it is often called the agricultural revolution.

9. The Agricultural Revolution
The Agricultural Revolution allowed human populations to grow at an unprecedented rate.
As populations grew, they began to concentrate in smaller areas placing increased pressure on the local environments.

10. The Agricultural Revolution
The agricultural revolution changed the food we eat.
The plants we grow and eat today are descended from wild plants.
However, during harvest season farmers collected seeds from plants that exhibited the qualities they desired, such as large kernels.
These seeds were then planted and harvested again. Overtime, the domesticated plants became very different from their wild ancestors.

11. The Agricultural Revolution
Many habitats were destroyed as grasslands, forests, and wetlands were replaced with farmland.
Replacing forest with farmland on a large scale can cause soil loss, floods, and water shortages.

12. The Agricultural Revolution
The slash-and-burn technique was one of the earliest ways that land was converted to farmland.
Much of this converted land was poorly farmed and is no longer fertile.

13. Iowa Before Agriculture

14. The Industrial Revolution
The Industrial Revolution involved a shift from energy sources such as animals and running water to fossil fuels such as coal and oil.
This increased use of fossil fuels changed society and greatly increased the efficiency of agriculture, industry, and transportation.
For example, motorized vehicles allowed food to be transported cheaply across greater distances.

15. The Industrial Revolution
In factories, the large-scale production of goods became less expensive than the local production of handmade goods.
On the farm, machinery reduced the amount of land and human labor needed to produce food.
With fewer people producing their own food, the populations in urban areas steadily grew.

16. The Agricultural Revolution The Industrial Revolution
Hunter-Gatherers
The Agricultural Revolution
The Industrial Revolution
Characteristics
Get food by collecting plants and hunting wild animals
Practiced growing food, breeding, and caring for plants
Started using fossil fuels such as coal and oil (Energy Shift)
Effects on Environment
Over-hunting caused extinction of some species
Habitats were destroyed because grasslands, forests, and wetlands were replaced with farmland.
Introduced artificial substances into the environment that cannot be recycled like plastic.

17. Our Environment Through Time Continued: Improving the Quality of Life
The Industrial Revolution introduced many positive changes such as the light bulb.
Agricultural productivity increased, and sanitation, nutrition, and medical care vastly improved.

18. Improving the Quality of Life
However, the Industrial Revolution also introduced many new environmental problems such as pollution and habitat loss.
In the 1900s, modern societies began to use artificial substances in place of raw animals and plant products.
As a result, we know have materials such as plastics, artificial pesticides, and fertilizers.

19. Improving the Quality of Life
Many of these products make life easier, but we are now beginning to understand some of the environmental problems they present.
In fact, much of environmental science is concerned with the problems associated with the Industrial Revolution.

20. What are our Main Environmental Problems?
Environmental problems can generally be grouped into three categories:
Resource Depletion
Pollution
Loss of Biodiversity

21. Major Environmental Problems
Resource Depletion
Resources can be renewable (water) or nonrenewable (petroleum).
The supply of nonrenewable resources like fossil fuels and minerals will eventually run out.
The supply of renewable resources is often used so quickly that it cannot be replenished.

22. Major Environmental Problems
Pollution
Undesired change in air, water, or soil that affects the health of living things.
Biodegradable pollution will break down naturally over time.
Nondegradable pollution does not break down.

23. Major Environmental Problems
Loss of Biodiversity
Biodiversity is the number of different species present in an ecosystem.
Extinction, or the complete loss of a species, is a natural event that can be accelerated by human actions.
The Tasmanian tiger is the only known mammal to become
extinct in the past 200 years on the island of Tasmania.
During the same period of time, on nearby Australia,
23 birds, 4 amphibians, and 27 mammal species have become extinct.

24. Tragedy of the Commons
An ecologist named Garrett Hardin wrote an essay describing the source of environmental problems as a conflict:
Short-term interests of individuals
versus…
Long-term interests of civilization and the Earth itself

25. The Tragedy of the Commons
Garrett Hardin wrote an essay called “The Tragedy of the Commons”, describing a major source of environmental conflict: resources that are not privately owned or regulated will often be depleted.
The self-interest of individuals takes priority over the best interests of the entire population.

26. Tragedy of the Commons Each villager owns a small herd of sheep.
The only place for the sheep to graze is a commons in the center of the village.
A commons is an area that belongs to an entire village.
Likely outcome: Villagers obtain as many sheep as possible, allow to graze in the commons.

27. What if the commons was instead divided into sections that was owned by each villager?
Because the land is owned, individuals are much more likely to plan and use it for the long-term.

28. A small village consists mostly of farmers that raise and sell sheep at a nearby city. The only place for the sheep to graze is a commons in the center of the village.
A commons is an area that belongs to no individual; it is shared by the entire society.
The villagers in this situation will have an incentive to obtain and graze as many sheep as possible, leading to overgrazing and barren lands.
A second village has its grazing land divided into nine fenced sections, each of which is owned by a different family.
These families will carefully control the amount of grazing to ensure their land is usable in the long-term.
Sheep grazing, Hawf Protected Area, Yemen.
Picture by Sebastian Kennerknecht

29. Tragedy of the Commons
Activity

30. Ecological Footprint
An ecological footprint is one measurement of a person’s resource use.
Includes the amount of space needed to support each person in a nation, including forests, farms, cities, etc.

31. The Goal: A Sustainable World
Sustainability
Human needs are met so that the population can survive
indefinitely.
“Meeting the needs of the
present without
compromising the ability of
future generations to meet
their own needs.”
Brundtland Commission, 1987