The Environmental
Challenges We Face
Chapter 1
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
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Overpopulation
Overconsumption of natural resources: topsoil, water, air
Transforming and destroying natural environments
Eradicating unique species
Human-induced climate change
A World in Crisis
Human Impacts on the
Environment
• Learning Objectives:
1. Distinguish among highly developed
countries, moderately developed countries,
and less developed countries.
2. Relate human population size to natural
resources and resource consumption.
3. Distinguish between people overpopulation
and consumption overpopulation.
4. Describe the three factors that are most
important in determining human impact on
the environment.
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
Linear vs. Exponential
• Linear growth - a quantity increases by
a constant amount per unit of time: 2, 4,
6, 8 or 1, 3, 5, 7, 9 & so on.
• Exponential growth - a quantity
increases by a fixed percentage of the
whole in a given time: 1, 2, 4, 16
Environmental InSight
Environmental InSight
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
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
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
Human Impacts on the
Environment
Gap between Rich and Poor
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)
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
3 Types of Resources
1. energy resources:
coal, oil, natural gas, uranium,
2. metallic mineral resources
iron, copper, aluminum, &
3. nonmetallic mineral resources
salt, clay, sand, & phosphates
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We convert these raw materials into
many everyday items we use, & then
we discard, reuse, or recycle them.
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
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
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
Human Impacts on the
Environment
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!!!
Human Impacts on the
Environment
Human Impacts on the
Environment
Population, Consumption, and Environmental
Impact
• I=PxAxT
• 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
Human Impacts on the
Environment
Global Climate Change
1. How do highly developed countries,
moderately developed countries, and less
developed countries differ regarding
population growth and per person incomes?
2. How is human population growth related to
natural resource depletion and
environmental degradation?
Sustainability and Earth’s Capacity
to Support Humans
• Learning Objectives:
1. Define environmental sustainability.
2. Identify human behaviors that threaten
environmental sustainability
Sustainability and Earth’s
Capacity to Support Humans
• Sustainability:
– Ability to meet current needs without
compromising the ability of future generations to
meet their needs
– Environment will function indefinitely
– Based on:
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Effects of our actions on the environment
Earth’s resources are finite
Understanding impacts of consumption
Shared responsibility for environmental sustainability
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
Environmental InSight
The Tragedy of the Commons
• One cause of environmental degradation is
overuse of common-property resources,
which are owned by none & available to all
users free of charge.
• Most are potentially renewable.
• It happens because each user reasons, "If I
don't use this resource, someone else will.
The little bit I use or pollute is not enough to
matter"
Global Environmental Issues
Global warming
Deforestation
Global Environmental Issues
Threatened Oceans
Desertification
Global Environmental Issues
Polar Ice caps
Ozone Depletion
Global Environmental Issues
Environmental stress factor
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?
Focus on Sustainability
Global Climate Change
1. What is environmental sustainability?
2. Which human behaviors threaten
environmental sustainability?
Environmental Science
• Learning Objectives:
1. Define environmental science.
2. Outline the steps of the scientific method.
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
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
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
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Data must be analyzed and interpreted
Not based on faith, emotion, intuition
Requires repeatability and scrutiny
No absolute certainty
Requires reevaluation
Ongoing process
How We Handle Environmental
Problems
• Learning Objectives:
1. List and briefly describe the five stages of
solving environmental problems.
How We Handle Environmental Problems
Global Climate Change
1. What are the five steps used to solve an
environmental problem?
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
Case Study