 In step five of this capstone project, we're going to sum up all of the costs associated with your plan. So let's say you've chosen a carbon emission scenario, you've chosen the per capita energy scenario, you've chosen the population limit and all the other parameters, and then you run the model and it'll calculate the global temperature change in a second here. There it is, and we see, in this case I would let it get too high, four and a half degrees, more I mean, so that's too much. But anyway, from that it will calculate the climate damage costs and so this is using that same relationship between the global temperature change and the cost, the economic cost associated with climate change that we used in the previous model. So that's one of the costs and then that's added to, that's combined with all the other costs. So the cost of carbon based energy, the cost of renewable energy here to the cost of conservation, in other words reducing the per capita energy demand here, and the climate damages which we just talked about, that combines to give the total cost. So you can see here with this scenario by the end, I've got something like 90 trillion dollars of cost associated with this plan. And so, you know, as you make different choices about these parameters, you can kind of keep track of, well, what is the ending cost here? So that's one way to do it. There are other ways to kind of keep track of that cost and compare one set of assumptions or scenario with another one. And so we'll look at a few other things here that will be helpful. So remember, the population is growing over time, okay? And the other thing that's happening is the economy is growing over time. This is the gross economic output, global economy starting here at about 56 trillion and then it rises at the end to 600 trillion. So we can scale these costs according to the size of the economy and also according to the size of the population. Here's one way to do it. We take the total cost, we divide it by that gross output that gives us the relative total cost here. So this is kind of like a fraction of the total global economy that is tied up in these energy and climate costs. And so you can see it's hovering here at something around 20%. But then it actually starts to decrease as time goes on because the economy is growing faster than these costs are. So that comes down. That's sort of an interesting thing to look at and you can compare that from one scenario to another. Another interesting thing to look at will be the sum of the costs per person. So in a way, this might be your ultimate scorecard for determining which of your plans or which scenario is the best because here you're kind of making it fair by scaling it to the population so it's a cost per capita. And this is summed up over all of the years. So it's not just a value for one year or the next year, but this is for all of the years. And what you want to do is to minimize this. So at the very end here, you get one number, 850 trillion. That's cost per person summed up over this whole time. You want that to be the smallest possible. So the smallest possible value there is economically speaking, the best pathway for the future. The best set of assumptions about carbon emissions and energy demand population and all these other things. So that's your aim. This would be maybe the one graph in the model to focus on maybe a little bit more than all the others in determining which scenario is the best.