ENV101 Lecture 2:
Key themes in environmental science
Learning objectives
1.
Basic concepts related to human population growth
and the links to famine and food crises
2.
Basic concepts associated with sustainability
3.
How human and natural processes can transcend
national boundaries
4.
Relationship between human population growth and
changes in urbanisation
5.
Justifications used to attach value to the environment
6.
Basic principles associated with the scientific process
Consider the following statement:
True or False: Hunting whales to extinction as rapidly
as possible is the most financially sensible way to
conduct whaling operations
Environmental science is a group of sciences
that attempts to explain how life on Earth is
sustained, what leads to environmental
problems and how these problems can be
resolved
Key Themes in Environmental Science
1. Human population growth
• The environmental problem
2. Sustainability
• The environmental goal
3. A global perspective
• Many environmental problems require global solutions
4. An urbanizing world
• Large populations live and work in urban environments
5. People and nature
• Both are intimately integrated and affect each other
6. Science
• Science can provide solutions
1. Human Population Growth
• In some ways the underlying
issue of the environment
• World population (World
Bank Pop. Statistics)
• 1961: ± 3.1 billion
• 1971: ± 3.8 billion
• 1981: ± 4.5 billion
• 1991: ± 5.4 billion
• 2001: ± 6.1 billion
• 2011: ± 7 billion
• 2022: ± 8 billion
Population Growth in South Africa
1. Human Population Growth
Famine and Food Crises
• Following drought in the Sahel
region (1970’s) 500 000 people
starved to death while millions
more were permanently affected
by malnutrition
• Famines occur due to complex
system interactions
(environmental, socio-economic,
technological, population
numbers)
• As of 16 Jan 2013 the UCL
Department of Space and Climate
Physics estimates that ± 98 million
people live under exceptional
drought conditions*
Nigerian women dig a trench to collect rainwater near the village of
Tibiri, in Niger's southern Zinder region. Photograph: Issouf
Sanogo/AFP/Getty Images
*defined as exceptional and widespread
crop and pasture losses; exceptional risk of
fire; shortage of water in reservoirs, streams
and wells creating water emergencies
2. Sustainability
• In the context of geologic time the changes we made
to the environment will be erased
• Sustainability has two formal scientific meanings:
- Sustainability of resources (e.g. global fish stocks)
- Sustainability of an ecosystem
• Carrying capacity: the maximum number of
individuals of a species that can be sustained by an
environment without decreasing the capacity of the
environment to sustain that same number in the
future.
3. A Global Perspective
• Impacts can transcend national boundaries
• Some impacts can even reach global proportions
• e.g. The emission of greenhouse gasses which lead to global
changes in temperatures
• https://www.youtube.com/watch?v=x1SgmFa0r04
• Natural processes can have global consequences
• Accumulation of free oxygen in atmosphere 2000 Ma ago
• Led to the ‘Oxygen Crises”
• https://thewonderofscience.com/phenomenon/2018/6/15/
the-great-oxygenation-event
4. An Urbanizing World
4. An Urbanizing World
• We are increasingly becoming an urban species
2%
8%
12%
1900:
1950:
Rural
21%
71%
86%
Cities < 1 mil
Cities > 1mil
2000:
23%
24%
53%
2020:
27%
35%
38%
Source: Fellman, J.D., Getis, A.,
Getis, J., 2003: Human
Geography: Landscapes of
Human Activities, McGraw Hill,
Boston
4. An Urbanizing World
• Urban areas are growing
• In 2008, for the first time more than half of the global population
lived in cities. Expected to increase to two thirds by 2025
• Number of megacities (>10 mil people) increased from 2 in 1950 to
22 in 2005
• Large numbers of cities are located along rivers and the coast
• Agricultural areas associated with river floodplains as well as
wetlands along the coast are being impinged upon
5. People and Nature
• People and nature are intimately
integrated
• Our views of the environment (value
system) determines how we use the
environment
• The value of the environment based
on eight justifications:
1.
2.
3.
4.
5.
6.
7.
8.
Utilitarian
Ecological
Aesthetic
Recreational
Moral
Cultural
Inspirational
Creative
5. People and Nature
• Utilitarian Justification (materialistic)
- Some aspect of the environment is valuable
because it benefits individuals economically
or is directly necessary for human survival.
- e.g. Conserving wildlife due to the benefits
associated with tourism
• Ecological Justification
- An ecosystem is necessary for the
survival of some species of interest to us,
or that the system itself provides some
sort of benefit
- e.g. Conservation of mangrove
ecosystems because they harbour fish
that are of economic importance
5. People and Nature
• Aesthetic and Recreational Justification
- Relates to our appreciation of the beauty of
nature and our desire to get out and enjoy it
- e.g. people who’d prefer to live in an area
with wilderness rather than in one without
• Moral Justification
- The belief that various aspects of the
environment have the right to exist and we
have a moral obligation in this regard
- e.g. United Nations General Assembly World
Charter for Nature (signed 1982) states that
species have a moral right to exist
5. People and Nature
• Cultural Justification
- Different cultures have many of the
same values, but also some different
values, with respect to the environment
- e.g. Buddhist monks who will move
disturbed earthworms from a
construction site vs. the killing of
dolphins by Japanese fisherman
• Inspirational Justification
- Conservation based on its benefits to
the human spirit (inner-selves)
• Creative Justification
- Nature as a source of creative
inspiration
- e.g. artists
6. Science
• Knowing the scientific data and understanding its
implications
• Precautionary Principle
- When there is a threat of serious, perhaps even
irreversible, environmental damage, we should not wait
for scientific proof before taking precautionary steps to
prevent potential harm to the environment
- Recognizes the need to evaluate all the scientific
evidence we have and to draw provisional conclusions
while still continuing the investigation
6. Science
• Science is a process
- Results in conclusions, generalizations, scientific theories and
scientific laws
• Modern science does not deal with things that cannot be
tested by observation
• Observations may be made by any of the 5 senses or by
instruments that measure beyond what we can sense
- Qualitative data: non-numerical data (e.g. animal species name)
- Quantitative data: numerical data (e.g. concentration of toxin)
• Inferences are generalizations that arise from a set of
observations
6. Science
• Variables
• Dependant:
- A variable that changes in response to changes in an independent
variable.
• Independent:
- In an observational study it is the variable that is believed by the
investigator to affect an outcome (dependant variable).
• Reasoning approaches
• Deductive reasoning:
- Drawing a conclusion from initial definitions and assumptions by
means of logical reasoning.
• Inductive reasoning:
- Drawing a general conclusion from a limited set of specific
observations.