1. The Environmental Challenges We Face
Chapter 1

2. A World in Crisis Earth provides raw materials and energy for Life
Earth is approx 4.5 Billion years old
Modern humans appeared in Africa 195,000 yrs ago
Human populations have grown and expanded in range
Technology has allowed humans to live better (at least in developed nations)
Humans are the most significant agent of environmental change
Overpopulation
Overconsumption of natural resources: topsoil, water, air
Transforming and destroying natural environments
Eradicating unique species
Human-induced climate change

3. A World in Crisis

4. Human Impacts on the Environment
Learning Objectives:
Distinguish among highly developed countries, moderately developed countries, and less developed countries.
Relate human population size to natural resources and resource consumption.
Distinguish between people overpopulation and consumption overpopulation.
Describe the three factors that are most important in determining human impact on the environment.

5. Human Impacts on the Environment
Overpopulation
Earth’s central environmental problem
Links all other environmental problems together
World’s population continues to grow and has grown very fast
1960: 3 billion people
1975: 4 billion
1987: 5 billion
2009: 6.8 billion
People consume food and water, use energy and raw materials and produce waste
Several more billion people will be added in the 21st century, even if we are proactive about population growth

6. Environmental InSight

7. Environmental InSight

8. Human Impacts on the Environment
Poverty
A condition in which people are unable to meet their basic needs for food, clothing, shelter, education, or health.
One in four people lives in extreme poverty (less than $2/day): 3.3 billion people
Poverty is associated with short life expectancy, illiteracy, inadequate access to health services, safe water, balanced nutrition

9. Human Impacts on the Environment
Population Growth
Projected 7.7–10.6 billion people depending on fertility rate
Current fertility rate is 2.6 children/woman
Family planning efforts
World’s population may stabilize by end of 21st century
Can Earth support so many people?
We don’t know
Quality of life depends on being able to produce enough food in a sustainable manner
Without destroying the biological communities that support life on our planet

10. Human Impacts on the Environment
Population Size
Number of people
Population Consumption
Use of materials and energy
Economic Growth
Expansion of the output of a nation’s goods and services
Intimately related

11. Human Impacts on the Environment
Gap between Rich and Poor
Highly Developed Countries (Rich, HDCs)
Complex industrialized bases, low rates of population growth, and high per person incomes
18 % of the world’s population
US, Canada, Japan, most of Europe

12. Human Impacts on the Environment
Gap between Rich and Poor
Poor Countries: 82% of world’s population
Moderately Developed (MDCs)
Medium levels of industrialization, lower per person incomes than highly developed countries, few opportunities for education and health care
Mexico, Turkey, South Africa, Thailand
Less Developed (LDCs)
Low levels of industrialization, high population growth, very high infant death rates, very low incomes, mostly agriculture based, cheap unskilled labor
Bangladesh, Mali, Ethiopia, Laos

13. Human Impacts on the Environment
Gap between Rich and Poor

14. Human Impacts on the Environment
Population, Resources, and the Environment
Developing countries
Rapid population growth is overwhelming
Natural resource depletion for survival (soils, forests, water)
Developed countries
Slower population growth
Higher rate of consumption beyond what’s necessary for survival (TV, computers, jet skis)

15. Human Impacts on the Environment
Types of Resources
Nonrenewable
Limited Supply: minerals, fossil fuels
Once they are gone, they are gone
Renewable/Potentially Renewable
Virtually unlimited: solar power, water, soil, forests
Replenished over short periods (days to decades)
Easy to overexploit nonrenewable
Soil, fresh water, clean air

16. Human Impacts on the Environment
Resources and Population
Rapid population growth can cause resources to be overexploited
Critical in developing countries
Economic growth tied to natural resource exploitation
Choice between short term and long term
Poverty drives natural resource exploitation
Must use resources to survive, which degrades them and shuts down future opportunities for development

17. Human Impacts on the Environment
Population Size and Resource Consumption
A country is overpopulated if the demand on its resources results in damage to the environment.
Can be overpopulated in 2 ways:
People Overpopulation
Consumption is high because there are too many people, even if individual consumption is low
Consumption Overpopulation
Consumption is high because each individual consumes too much, even if total population is low

18. Human Impacts on the Environment
Population Size and Resource Consumption
Highly developed countries have less than 20% of the world’s population, but consume:
86% of aluminum
76% of timber
68% of energy
61% of meat
42% of fresh water
Also, produce 75% of waste and pollution

19. Human Impacts on the Environment

20. Human Impacts on the Environment
Population Size and Resource Consumption
Ecological Footprints
The amount of land, fresh water, and ocean required on a continuous basis to supply a person with food, wood, energy, water, housing, clothing, transportation, and waste disposal.
Earth has 11.4 billion ha = 28.2 billion acres of productive land and water
11.4/6.8 billion people = 1.8 ha (4.3 acres)
Currently, average ecological footprint is 2.7 ha (6.7 acres)
US footprint is 9.4 ha (23.3 acres) if everyone in the world had the same, we would need 4 Earths!!!

21. Human Impacts on the Environment

22. Human Impacts on the Environment
Population, Consumption, and Environmental Impact
I = P x A x T
I: Environmental impact
P: Population (number of people)
A: Affluence per person (amt of resources)
T: Technology used to get resources
Interpret results with care!
Ultimate goal: make consumption sustainable

23. Human Impacts on the Environment

24. Global Climate Change
How do highly developed countries, moderately developed countries, and less developed countries differ regarding population growth and per person incomes?
How is human population growth related to natural resource depletion and environmental degradation?

25. Sustainability and Earth’s Capacity to Support Humans
Learning Objectives:
Define environmental sustainability.
Identify human behaviors that threaten environmental sustainability

26. Sustainability and Earth’s Capacity to Support Humans
Ability to meet current needs without compromising the ability of future generations to meet their needs
Environment will function indefinitely
Based on:
Effects of our actions on the environment
Earth’s resources are finite
Understanding impacts of consumption
Shared responsibility for environmental sustainability

27. Sustainability and Earth’s Capacity to Support Humans
We are not currently living sustainably:
Using nonrenewable resources as if they were renewable (e.g., fossil fuels)
Using renewable resources faster than nature can replenish them
Polluting the environment beyond capacity
Unchecked population growth, without regard to Earth’s finite resources and ability to deal with waste

28. Environmental InSight

29. Global Environmental Issues
Global warming Deforestation

30. Global Environmental Issues
Threatened Oceans Desertification

31. Global Environmental Issues
Polar Ice caps Ozone Depletion

32. Global Environmental Issues
Environmental stress factor

33. Sustainability and Earth’s Capacity to Support Humans
If we continue to live unsustainably, Earth may not recover
What changes are we willing to make?

34. Focus on Sustainability

35. Global Climate Change What is environmental sustainability?
Which human behaviors threaten environmental sustainability?

36. Environmental Science
Learning Objectives:
Define environmental science.
Outline the steps of the scientific method.

37. Environmental Science
Interdisciplinary study of humanity’s relationship with other organisms and the physical environment
combines information from many fields:
biology, geology, geography, chemistry, economics, agriculture, law, politics, ethics, etc.
Ecology is a basic tool
Atmospheric Science
Environmental Chemistry
Geosciences

38. Environmental Science
Goals
Establish general principles about how the natural world functions
Identifying, understanding, and solving problems that we have created
Not just ‘doom and gloom’ list of problems
Focus on solving problems

39. Environmental Science
Science as a Process
Not just a collection of facts
Systematic way of studying the natural world
Requires collection of data through
Observation and experimentation
Data must be analyzed and interpreted
Not based on faith, emotion, intuition
Requires repeatability and scrutiny
No absolute certainty
Requires reevaluation
Ongoing process

40. Environmental Science
The Scientific Method
Process that scientists use to answer questions or solve problems
Recognize a question/problem
Develop a hypothesis (educated guess) to explain the problem
Design and perform an experiment to test the hypothesis
Analyze and interpret the data to reach a conclusion
Share knowledge with scientific community

41. The Scientific Method

42. Environmental Science
The best hypotheses make predictions
Predictions provide a way to test hypotheses
If experiment refutes hypothesis, hypothesis is rejected
If hypothesis is verified repeatedly, hypothesis is strong
Science progresses from uncertainty to less uncertainty
Science is self-correcting even though it never ‘proves’ anything

43. Environmental Science
Experiments test hypotheses
Variable: factor that influences a process
To test a hypothesis, two experiments are carried out:
Experimental Group: the chosen variable is altered in a known way
Control Group: the chosen variable is not altered
We can ask: What is the difference (if any) between the two groups?
Any differences would be due to the experimental variable

44. Environmental Science
Scientific Theory
An integrated explanation of many hypotheses, each supported by many observations and experiments.
Simplifies and clarifies our understanding of the natural world.
Solid ground of science
Generally accepted as ‘true’, even though there is no absolute truth in science
Contrast with general public’s use of theory, as a guess, or hypithesis

45. Environmental Science
Science is constantly evolving
As new evidence comes to light, conclusions may change
Therefore, scientific conclusions are provisional, which doesn’t mean they are invalid.
E.g., smoking and cancer

46. Global Climate Change
What is environmental science? What are some of the disciplines involved in environmental science?
What are the five steps of the scientific method? Why is each important?

47. How We Handle Environmental Problems
Learning Objectives:
List and briefly describe the five stages of solving environmental problems.

48. How We Handle Environmental Problems

49. Global Climate Change
What are the five steps used to solve an environmental problem?

50. EnviroDiscovery NIMBY = not in my backyard
NIMTOO = not in my term of office
Examples:
People don’t want power plants, landfills, incinerators nearby
Politicians want to be reelected, so they don’t support those decisions in their districts

51. EnviroDiscovery

52. Case Study The New Orleans Disaster: Hurricane Katrina
Storm damage was increased because of human alteration of the natural landscape:
Canals were built for navigationallowed salt water to intrude and kill marsh vegetation
Levees were built to stop floodingsediments did not build up to replenish the land
Settlements were built on drained wetlands
City was subsiding due to lack of bedrock

53. Case Study