Meteorology/Agronomy/EnvSci/EnvSt 404/504


Final Exam

Spring 2003
  1. The Gaia Hypothesis and Earth System Science


  2. The Gaia Hypothesis was first articulated by Dr. James Lovelock in 1979 and basically states that living systems on Planet Earth regulate the climate system in such a way as to provide a favorable condition for its (life's) continued existence.

    The Gaia Hypothesis is often described by "Daisy-World", a planet with vegetation consisting of black daisies and white daisies. When the global mean temperature of the planet falls, white daisies die off more than black daisies, which slows the cooling and eventually reverses the global cooling trend. When the temperature of the planet rises, black daisies die off more than white daisies, which slows the warming and reverses the global warming trend. This is a simple explanation of how the biological systems presumably regulate their own environment.

      1a. Daisy World uses the color and number of daisies to regulate the environment. Discuss actual physical processes that perform this function on Planet Earth.

      1b. Consider the self-regulating nature of Planet Earth (not Daisy World) with and without the existence of humans with their current level of technology. Discuss how humans with current technology might be able (or not able) to keep the equilibrium (homeostasis) for longer periods than a biological world without humans.

      1c. Suppose humanoids living in Daisy World find that white daisies can be processed to produce an aphrodisiac, which results in an explosion of humanoid population and a distorted balance of daisies. Give the Brundland Commission definition of sustainability and give two actions humanoids could take to comply with the mandate of the Commission and preserve Daisy World.

  3. Comment on the validity of each of the following statements and provide some discussion in support of your position:
    • 2a. Global climate change likely will cause food shortages and freshwater shortages in the next 50 years.

      2b. Limiting population growth in developing countries is the only way to avoid exceeding the carrying capacity of the planet in the next 50 years.

Each of these five questions counts 20 points.