Key Themes in Environmental Science

Transcription

1 Key Themes in Environmental Science

2 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

3 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

4 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

5 Population Growth in South Africa Population (in millions) Population of South Africa Year

6 1. Human Population Growth Famine and Food Crises Following a drought in the Sahel region during the 1970 s people starved to death while several million 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 This is defined as exceptional and widespread crop and pasture losses; exceptional risk of fire; shortage of water in reservoirs, streams and wells creating water emergencies

7 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.

8 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 Natural processes can have global consequences Accumulation of free oxygen in atmosphere 2000 Ma ago Led to the Oxygen Crises

9 4. An Urbanizing World

10 4. An Urbanizing World We are increasingly becoming an urban species 12% 2% 8% Rural 86% 21% 71% Cities < 1 mil Cities > 1mil 27% 35% 38% 23% 24% % Source: Fellman, J.D., Getis, A., Getis, J., 2003: Human Geography: Landscapes of Human Activities, McGraw Hill, Boston

11 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 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 Therefore agricultural areas associated with river floodplains as well as wetlands along the coast are being impinged upon

12 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. Utilitarian justification 2. Ecological justification 3. Aesthetic justification 4. Recreational justification 5. Moral justification 6. Cultural justification 7. Inspirational justification 8. Creative justification

13 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

14 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 thaat species have a moral right to exist

15 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

16 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

17 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

18 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

19 6. Science Models Deliberately simplified construct of nature Uncertainty Accuracy The extent to which the measurement agrees with an accepted value refers to what we know Precision The degree of exactness with which a measurement is made refers to how well me measure