 So let's now do an actual experiment here with our one-dimensional energy balance model, where we've now generalized the energy balance model to allow for discrete latitude zones. And we calculate the energy balance as we did before between the incoming solar radiation, the outgoing longwave radiation, the reflected radiation. So we use the same energy balance principles that we used in the zero-dimensional model. But now we're allowing for different solutions of the energy balance model in different latitude zones and importantly we are going to allow for these fluxes, these lateral fluxes of energy, F, between latitude zones, which represent the very important role that atmospheric and oceanic motions play in transporting heat on the hole from low latitudes to higher latitudes to make up for the imbalance between outgoing and incoming radiation at the tropics and at the poles. There's a surplus of energy at the equator, deficit of energy at the poles, and so we need these lateral fluxes to make up for that imbalance. So let's take a look at a problem that was first attacked using this sort of approach, the one-dimensional energy balance modeling approach. We're going to use a program that was written in MATLAB, and you can see this is sort of the heart of the program, does the energy balance calculations for each latitude zone. Here we've specified the lateral heat flux transport coefficient, F. We're using gray body parameters for the energy balance of the sort you saw before in the one-dimensional, zero-dimensional model, and we are now accounting for the possibility that the albedo will be vastly different depending on whether a particular latitude zone is ice-covered, in which case it has a relatively high albedo, or not ice-covered, in which case it has a relatively low albedo. And we will determine whether or not a latitude band is likely to be ice-covered through a simple threshold parameterization here, where if the average temperature for that latitude band is below minus 10 degrees Celsius in the annual average, then it will be ice-covered, and that's the assumption that we'll be making. It's not a bad assumption if you look overall at the relationship between mean annual temperatures and which latitude zones are indeed mostly covered by ice in the real world. And we will perform experiments in which we slowly change the solar constant from a relatively high value larger than today's solar constant to a relatively low value. And we'll see how the temperature of the Earth and of different latitude zones changes, and then we'll increase the solar constant from that low value to the high original value, and again see how Earth's temperature changes. Now we know that changing albedo will be coming into the problem. There will be transport of heat between different latitude zones, so this is a more sophisticated model than the sorts of models that we've looked at so far.