Chapter 1: Environmental Problems, Their Causes, & Sustainability

Transcription

1 Chapter 1: Environmental Problems, Their Causes, & Sustainability

2 all external conditions & factors that affect living organisms study of the relationships between living organisms & their environment interdisciplinary study of the role of humans on the Earth

3 Sustainability Sustainability: ability of a system to survive and function over time. Sustainable Yield: the highest rate at which a potentially renewable resource can be used indefinitely without.

4 Tragedy of the Commons Overuse of common-property (open-access) resources, which are owned by no one but are available to all users free of charge. (Garrett Hardin, 1968) Examples:, fish in the open ocean, migratory birds

5 Population & Development Population is increasing faster in developing countries than in developed countries. Developed countries are those that are, like the US. Developing countries are those that have, like Peru.

6 Developed nations contain 18% of the world s population, but consume 88% of the resources.

7 Wealth Gap Gross Domestic Product: All goods and services produced within a country during a year. Per capita GDP: The GDP divided by the (per person value). Since 1960, the gap in per capita GDP between rich, middle income, & poor has widened.

8 Environmental Impact Number of people (Population = P) Per capita consumption (Affluence = A) Amount of environmental degradation and pollution produced per unit of resource used (Technology = T) Population x Affluence x Technology = Environmental Impact P x A x T = I

9 Resources Renewable Resources: Perpetual resource: Examples: solar power, wind power, wave energy, geothermal Potentially renewable resource: can be replenished fairly rapidly if managed correctly. Must be harvested below the Examples: forests, soil, fresh water and air).

10 Recycling Recycling: Processing a resource into new products. Closed Loop- Can be recycled into the Open Loop or Downcycling: Products that can only be recycled into another type product (lesser quality). Example: Plastic bottle to a park bench

11 Pollution Point Source Pollution: Pollutants from a single, identifiable source, such as a power plant or sewage outfall. Nonpoint Source Pollution: Pollutants from, such as pesticide runoff or automobile exhaust. Which do you think is harder to address?

12 Chemical Pollutants Three factors affect the harmfulness of chemicals: 1. Chemical Nature: How active & harmful to living organisms? -Type of chemical -Solubility: soluble molecules bioaccumulate 2. Concentration: -Amount per unit of volume present in the environment.

13 Chemical Pollutants 3. Persistence- chemical remains in environment. Degradable: Broken down by chemical, physical, or biological processes. Example: Livestock manure is biodegradable Nondegradable: Can not be broken down. Examples: Lead, Mercury, Arsenic, Plastic

14 Often the environmental impact of a product is reflected in it price. Ex.: increased health care costs, clean-up etc.

15 Human Impact Ecological Footprint: The total amount of required to produce to goods and assimilate the wastes of an individual. Carbon footprint: The amount of emissions that results from the activities of an individual. There is much overlap between these two terms, but also differences. For example, oil has a large carbon footprint impact but it ecological footprint depends on how it was extracted.

16 Discuss with your table partner: Name at least 2 factors regarding the production and distribution of the food we eat that affect its ecological and/or carbon footprint. especially impacts carbon footprint Amount of Impacts both-

17

18 Ecological Footprint Figure 1-10

19 US Family Homes: Average Size Size of average US home has grown, even as the size of the average American family has shrunk. How will this affect your ecological footprint? How will this affect your carbon footprint?

20 The Four Principles of Sustainability Figure 1-17

21 Precautionary Principle

22 System Components: Inputs Throughputs Outputs Systems: Chapter 2-5 Characteristics of systems that make analysis and understanding difficult: Feedback loops Time lags Resistance to Change Synergy Chaotic Behavior Figure 2-10 Chaotic Consciousness by Iona Miller

23 Energy Energy: the capacity to do or transfer Types: Kinetic energy energy of motion. e.g., a moving automobile, Potential energy stored energy. e.g., a stretched rubber band, water stored behind a dam.

24 Electromagnetic Radiation The wavelength varies with both frequency and energy. Shorter wavelengths have a frequency and energy content than longer wavelengths. Increasing Frequency and Increasing Energy Increasing Wavelength

25 Energy Quality Energy quality is a measure of how useful an energy source is. High-quality energy is organized or concentrated. Low-quality energy is disorganized or dispersed. Example:

26 Energy Laws First Law of Thermodynamics: energy is, but may be converted from one form to another. (AKA Law of Conservation of Energy) Implies that in energy flows in systems can be followed also stated, "you can't get something for nothing", in terms of energy quantity. Einstein showed energy & matter can be interconverted; E = mc 2, but this is not applicable in Earth systems (but is applicable with regard to how the sun produces energy).

27 Energy Laws Second Law of Thermodynamics: when energy is converted from one form to another, some of the useful energy is always degraded to lower quality, more dispersed energy. (Also can be stated: entropy ) entropy is a measure of increased entropy means increased randomness or dispersion; degraded energy generally in form of

28 Discuss with your table partner: The flow of energy through a food chain forms an energy pyramid, with less available energy with each trophic level (step in the food chain). o How is this consistent with the First Law of TD? o What happens to the total energy? o What happens to the entropy? o What happens to the overall energy quality?

29 Ecological efficiency: The percentage of usable energy transferred from one trophic level to the next. What is the ecological efficiency for each step the food chain shown below? The ecological efficiency can range from 2% to 40%, with 10% being the typical ecological efficiency.

30 Positive Feedback Loops In a positive feedback loop, an input causes the system to change in the direction, the outcome. Example: As vegetation is removed, the exposed soil is eroded and degraded Figure 2-11 faster, which leads to more vegetation loss. Example: As temperature increases, ice melts at the poles, the darker color of the water/soil absorbs more heat causing an even greater increase in temperatures, leading to more ice melting.

31 Negative Feedback Loops In a negative feedback loop, an input causes the system to change in the direction from which it is moving. Example: Thermostat in house Example: temperature regulation in humans: increased body temperature leads to sweating, which leads to decrease in temperature Figure 2-12

32 Discuss with your table partner: A deer population has a large number of offspring. The next Spring, with a larger population an even greater number of offspring are born. Which type of feedback loop is this and WHY? feedback -output causes A deer population has a large number of offspring. There is inadequate food for this larger population which leads to an increase in deaths for the population. Which type of feedback loop is this and WHY? feedback- output cause. feedback tends to.

33 Discuss with your table partner: Sketch what you think the graphs of what each feedback loop will look like vs. time Positive Feedback Loops are ultimately unstable, since they lead to changes Time Negative Feedback Loops are ultimately stable, since they tend to changes. Time Remember: Negative feedback loops are not necessarily bad and positive feedback loops are necessarily good

34 Behavior of Complex Systems Time result when a change in a system leads to other changes after a delay. Examples: Lung cancer after years of smoking, Climate change after decades of carbon dioxide emission. Time lags can make it harder to respond effectively to environmental problems

35 Behavior of Complex Systems Resistance to change when a system has feedbacks that tend to maintain the system. Example: Air pollution has been slowing the effects of global warming. Synergy results when two or more processes so that the combined effect is more than the sum of their separate effects. Example: drug interactions, positive working relationships

36 Behavior of Complex Systems Chaotic Behavior results when or behavior is generated from within the system itself. Chaos can mask patterns. Example: day to day variations in weather, timing of mass extinction events.

37 Chaotic Behavior Butterfly Effect: the concept of sensitive dependence on in chaos theory, based on the work by Edward Lorenz. A small change at one place in a complex system can have large effects elsewhere. It is exhibited even by very simple systems. Example: a ball placed at the crest of a hill might roll into any of several valleys depending on slight differences in initial position.

38 Threshold level or Tipping point: Point where a fundamental change in the system results; Point of How do you determine where the tipping point is? can help, but it is very difficult, due to the complexity of systems. Example: Many arctic researchers believe that melting sea ice in the arctic has passed the tipping point for stability, and ice loss will continue to accelerate. The complexity of most systems in the environment (particularly systems on a global scale) make understanding, modeling, and predicting future outcomes very difficult.

39 Earth Systems are Incredibly Complex!