Problem
Solving for the temperature of Earth, Te, using the planetary energy balance principle, we get Te = 255 K = -18 oC, as demonstrated in class. However, Earth's average surface temperature is actually Ts = 15 oC. What is the difference between Ts and Te in degrees C (i.e. what's Ts minus Te), and, importantly, what is the reason for that difference, and how does it affect Earth's habitability?