lunes, 22 de noviembre de 2010

Resource use and pollution management


Carrying capacity: Maximum number of a species or “load” that can be sustainably supported by an environment.
Populations remain stable if DR and BR are equal.
There have been numerous examples of resource failure and the concecuences of human activity.
Human population size is not the only factor responsible for the impact on resources and on the environment.
Also to consider: Wealth, desires, needs, uses.
Population impact models work on the assumptions that all individuals (or similar populations) have the same needs and thus a similar impact.
Individual / population resource use is a dynamic principle.
Resources use varies with time/space.

Different resources use
  • MEDCs vs LEDCs
  • Urban vs Rural
  • Young communities vs Old communities

Impacts will vary in scale, type and severity.

Pollution
Adding substance or agent to the environment by human activity at a rate greater than that at which it can be rendered harmless by the environment.
Major sources
  • Combustion
  • Domestic waste
  • Industrial waste
  • Agricultural waste


Pollution management
Sources
  • Point source
  • Non point source

Detection and monitoring
  • Directly
  • Indirectly
  • Pollution indicators

BOD – amount of dissolved oxygen required to break down the organic material in a water volume through anaerobic or aerobic activity.
Indicator species (biotic index 1-10) through invertebrates, etc.
Three-level model of pollution management
Replace, regulate, restore
Waste management
  • Minimize waste: reduce, reuse, recycle
  • Disposal
  • Landfills
  • Incinerators

Organic waste management
Initiatives and agreement

domingo, 7 de noviembre de 2010

Sources of Energy

The main


1) Fossil fuels: By far the most exploited energy resource but not for much longer. Oil, coal, gas.
2) Nuclear energy: Highly productive but has hazardous issues.
3) Hydroelectric energy: Harnesses the kinetic energy of flowing water.
4) Solar energy: Renewable because the sun will be around for a few billion years more. Very expensive.

Others

Wind
Geothermal
Tidal
Hydrogen fuel cells
Biofuels
Biomass