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ENV 107 - Lecture 3


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basic issues and values of environmental science

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ENV 107 - Lecture 3

  1. 1. Outline 1  Gaia hypothesis  Urban world, urbanization and urban growth  Environmental Values and Knowledge and resources  Pollution and pollutants Lecture 3; MrL
  2. 2. Gaia hypothesis 2  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 Lecture 3; MrL
  3. 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 Lecture 3; MrL
  4. 4. Urban world, urbanization and urban growth 4  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. Lecture 3; MrL
  5. 5. POPULATION IN URBAN AREAS 5 % 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 Lecture 3; MrL
  6. 6. Megacities by 2015 6 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. Lecture 3; MrL
  7. 7. Environmental Values and Knowledge 7 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. Lecture 3; MrL
  8. 8. Placing a Value on the Environment (includes environmental resource) 8 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. Lecture 3; MrL
  9. 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. 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. 11. Placing a Value on the Environment 11 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 Lecture 3; MrL
  12. 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) Lecture 3; MrL
  13. 13. Taking decision on environmental issue based on knowledge and value 13 Example: Rampal coal power plant vs Moheshkhali coal power plant: why two different views by the environmentalist? Lecture 3; MrL
  14. 14. Pollution and pollutants (details will be discussed in other classes) 14 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 Lecture 3; MrL
  15. 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. 15 Lecture 3; MrL
  16. 16. Any question? 16 Lecture 3; MrL