Sustainability

If the human race is expecting to continue to flourish on this planet with an increasing population, doing things in a sustainable way is going to need to be of utmost importance. But first lets lay out what sustainability is. The Earth can provide a set amount of resources while also dealing with the byproducts of our civilization. These resources can be put into two basic groups. One group is finite resources. These are things like oil or rare metals. Since our consumption is much greater than what is available on the planet, once these are gone they are gone. The other group is renewable or infinite resources. These entail the trees, wind, or sun light. They are available to us at either fixed or variable rates and can be assumed to be available to us for the foreseeable future, pending some major change.

We as a society use these resources at a certain rate to build our civilization. With finite resources the faster we use them the faster they run out. This is not sustainable. Renewable resources are general assumed to be sustainable, and they are, as long as the rate at which we use them does not exceed the rate of which the Earth can provide or replenish them. Our society can therefore only be sustainable in the long term if we switch our resource use from finite sources to renewable or infinite resources.

Sources:
http://www.epa.gov/sustainability/basicinfo.htm#sustainability

Carrying Capacity of the World

Earths Carrying Capacity is the number of humans that the can indefinitely survive on the available resources of the world.  Some argue that the current population of the world is already well beyond this number while others believe the entire idea of quantifying this number to be foolish.  Skeptics say that it is impossible to take into account all of the factors that go into calculating such a number and that even if this were possible, the variables are ever changing.  There is no way to predict what new technologies will arise that allow for a more efficient use of the earth's resources and thus an increase in the carrying capacity.  In fact, the higher the population, the more likely it becomes that new technologies will be developed because of the larger pool of knowledge to draw from.

Some believe that there is a sort of equilibrium that could be reached.  As a species population increases, more resources are used, resources become scarce, part of the population dies off, resources are replenished, and the species population is allowed to increase again.  A balance is reached when the species population and the availability of resources become stable and the two can coexist.  A good example of this is the moose and wolf population which is detailed on Wikipedia:

"Without the wolves, the moose would overgraze the island's vegetation. Without the moose, the wolves would die. The first scientists who studied the issue thought that the wolves would eventually overpopulate and kill all the moose calves, then die from famine. This has not occurred as inbreeding, disease and environmental factors have limited the wolf population naturally."

The population of the wolves is kept in check by natural causes (inbreeding, disease, etc.) and the population of the moose is kept in check by the wolves.  Neither species becomes overpopulated so the amount of resources remains plentiful and the carrying capacity of the land is not breached.  Measuring this number becomes much more complex with humans because of the vast variety of resources that people consume.

Sources:

http://en.wikipedia.org/wiki/Carrying_capacity#Humans

http://www.newscientist.com/blog/environment/2008/06/what-is-earths-carrying-capacity.html

http://science.howstuffworks.com/environmental/green-science/earth-carrying-capacity2.htm

Questions Posed in Class (Week 1)

- Why should we think about energy?
- What is sustainability?
- What is the carrying capacity of earth?
- Can the current energy consumption profile last?
- If the current enrgy profile of the world is sustained what impact will it have on the environment?
- What is the greenhouse effect?
- What are greenhouse gases?
- What are the sources of greenhouse gases?
- What is the Global warming potential (GWP)?
- Where are greenhouse gasses coming from? (What gases are involved and what is their contribution to the greenhouse effect?, What fuels contribute and how much?, What countries contribute and how much?, What sectors of economy contribute and how much?)
- Is human activity, particularly the use of fossil fuels causing irreversible changes in the earth's climate?
- What is the scientific basis for AGW (anthropogenic global warming)?