In my second lecture, we'll discuss what determines temperature gradients in the atmosphere-ocean system. Energy transports in the atmosphere and ocean cause temperature gradients to be much smaller on Earth than expected from solar heating alone. It is possible to model energy transports with a simple one-dimensional PDE known as the "Energy Balance Model," which assumes diffusive transport of heat. We will discuss justifications from turbulence theory for the diffusive assumption, how the presence of latent heating alters energy transports, and other factors such as ice coverage that influence the temperature gradient over a variety of parameter ranges.