Required Reading (everyone):

• Understanding the Forecast, Ch. 7, pp. 73–81.

Reading Notes:

The central concept of this chapter is feedback loops. This will be very important as we go forward through the semester. So far we have looked at systems where a change (a forcing) produces an effect (adding CO₂ to the atmosphere causes the temperature to rise). A feedback happens when the effect becomes a new forcing that produces additional effects in a cycle.

Feedbacks can either amplify or diminish the effects of an initial forcing, depending whether the feedback is positive or negative.

• Understand the concept of positive and negative feedbacks.
• Understand how the following feedbacks work and whether each is positive or negative:
  • Stefan-Boltzmann feedback
  • Ice-albedo feedback
  • Water vapor feedback
• What is a runaway greenhouse effect? What prevents Earth from having a runaway greenhouse?