basic issues and values of environmental science

1. Outline
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 Gaia hypothesis
 Urban world, urbanization and urban growth
 Environmental Values and Knowledge and resources
 Pollution and pollutants
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2. Gaia hypothesis
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 The hypothesis states that life manipulates the
environment for the maintenance of life.
 For example, some scientists believe that algae
floating near the surface of the ocean influence
rainfall at sea and the carbon dioxide content of the
atmosphere, thereby significantly affecting the global
climate.
 It follows, then, that the planet Earth is capable of
physiological self-regulation
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3. 3
The Gaia hypothesis is really a series of hypotheses:
1. Life, since its inception, has greatly affected the planetary
environment. Few scientists would disagree.
2. Life has altered Earth’s environment in ways that have
allowed life to persist. Certainly, there is some evidence that
life has had such an effect on Earth’s climate.
3. Life deliberately (consciously) controls the global
environment. Few scientists accept this idea.
 The future status of the human environment may
depend in part on actions we take now and in coming
years.
James Lovelock first proposed the Gaia hypothesis
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4. Urban world, urbanization and urban growth
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 We are becoming an urban species because of rapid
growth of human population and changes in technology
 Our effects on the environment are more and more the
effects of urban life
EFFECTS OF URBANIZATION
 Urban growth overtakes agricultural land,
floodplains, coastal wetlands, which are important
habitats for many rare and endangered species.
 As urban areas expand, wetlands are filled in, forests cut
down, and soils covered over with pavement and
buildings.
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5. POPULATION IN URBAN AREAS
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% of population live in urban areas
 Developed countries: 75%
 Developing countries: 40%
 By 2008: more than 50% people lived in urban areas
 By 2025: 67% will live in urban areas
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6. Megacities by 2015
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Explain the
figure.
•Megacities with
at least 10 million
inhabitants—
increased from 2
in 1950 to 22 in
2005
•Most megacities
are in the
developing world
•By 2015 most
megacities will be
in Asia.
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7. Environmental Values and Knowledge
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Deciding what to do about an environmental problem
involves both science and values.
 Science/knowledge in environment: But to make this
choice, we must first know what is possible. That
requires knowing the scientific data and
understanding its implications.
 Value of environment: utilitarian (materialistic),
ecological, aesthetic, recreational, inspirational,
creative, moral, and cultural.
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8. Placing a Value on the Environment
(includes environmental resource)
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Utilitarian (materialistic) justification
 Some aspect of the environment is valuable because
it benefits individuals economically or is directly
necessary to human survival.
 Example, conserving lions in Africa as part of
tourism provides a livelihood for local people.
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9. 9
Ecological justification
 an ecosystem is necessary for the survival of some species of
interest to us
 Or the system itself provides some benefit.
 For example, a mangrove swamp
provides habitat for fish, and although
we do not eat mangrove trees, we may
eat the fish that depend on them. Also,
the mangroves are habitat for many
noncommercial species, some
endangered. Therefore, conservation of
the mangrove is important ecologically.
Placing a Value on the Environment
(includes environmental resource)
Lecture 3; MrL

10. 10
Aesthetic and recreational justifications
 our appreciation of the beauty of nature and our
desire to enjoy it.
 For example, many people find wilderness scenery
beautiful and would rather live in a world with
wilderness than without it.
Placing a Value on the Environment
(includes environmental resource)
Lecture 3; MrL

11. Placing a Value on the Environment
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Moral justification
 Various aspects of the environment have a right to
exist and it is our moral obligation to help them,
 or at least allow them, to persist.
 Example: dog park
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12. 12
Cultural justification
 Different cultures have many of the same values but also
some different values with respect to the environment.
 All cultures may value nature, but, depending on their
religious beliefs, may value it in different degrees of
intensity. For example, Buddhist monks when preparing
ground for a building may pick up and move disturbed
earthworms.
Placing a Value on the Environment
(includes environmental resource)
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13. Taking decision on environmental issue based on
knowledge and value
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Example:
Rampal coal power plant vs Moheshkhali coal
power plant: why two different views by the
environmentalist?
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14. Pollution and pollutants
(details will be discussed in other classes)
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Pollution
 An unwanted change in the environment caused by the
introduction of harmful materials or the production of
harmful conditions (heat, cold, sound).
Categories
 Infectious Agents: microorganisms, H1N1 flu pandemic
 Environmentally Transmitted Infectious Disease:
Salmonella, malaria
 Toxic Heavy Metals: Arsenic (As), Lead (Pb), Mercury
(Hg)
 Organic Compounds: pesticides
 Persistent Organic Pollutants: DDT, Aldrin etc
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15. References for today’s lecture
 BOTKIN, D. B. & KELLER, E.A. 2011.
ENVIRONMENTAL SCIENCE: EARTH AS A
LIVING PLANET. JOHN WILEY & SONS, INC.
 If you don’t find in this book read directly from the
class note.
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16. Any
question?
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