Lecture 4

Question 1

Cold Sun Paradox/Hot Sun Catastrophe

Answer 1

The solar luminosity has increased over the Earth’s history. Why wasn’t it too cold for life in the earlier epochs of the Earth? Why hasn’t the Earth heated up over the past few billion years?

Question 2

Gaia Hypothesis

Answer 2

Life itself acts to stabilize the climate.

Question 3

Daisyworld

Answer 3

Imaginary planet that demonstrates the relationship between the daisies and the planet’s climate.

Question 4

Albedo

Answer 4

The reflectivity of any planetary surface.

Question 5

Albedo in Daisyworld

Answer 5

Because temperature affects daisies, the change in temperature, caused by solar luminosity, changes the coverage of daisies. Eventually a new equilibrium is established but the final temperature is less than the initial effect of the the increased luminosity. This is so because of feedback factors.

Question 6

Negative Feedback

Answer 6

Change in equilibrium temperature is less than change in initial temperature. The feedback factor is less than 1.

Question 7

Positive Feedback

Answer 7

Change in equilibrium temperature is greater than change in initial temperature. The feedback factor is greater than 1.

Question 8

Feedback factor

Answer 8

Change in equilibrium temperature over change in initial temperature.

Question 9

What can cause a stable system to go unstable?

Answer 9

A large perturbation to a system while in the stable regime can cause the system to go unstable.