 Okay, so we were just looking at the carbon-free energy requirements and the red curve tells us how much carbon-free energy we would need to produce given the assumptions that we've made here and given the scenarios shown for both carbon emissions and CO2 concentrations. We can also see how our assumptions regarding each of these terms compare to historical numbers. Population growth in the past versus our projected population growth under this assumption that we've made of stabilizing global population at 11 billion later this century or early next century. The assumption of GDP per person relative economic expansion of 1.6 percent per year, these are the historical values, the pluses, and the curve shows what we're projecting for the future. Energy intensity, our curve sort of follows the past couple decades of data as far as energy intensity is concerned. So we might imagine that there have been some developments in technology that have led to a trend in recent decades that may be more representative of the trend we would expect in the future than say the numbers from the early 20th century. So our projected energy intensity over time sort of matches the past few decades of energy intensity information. Finally, carbon efficiency. This is the decline we're projecting as we become more carbon efficient in our energy usage fewer gigatons of carbon produce per terawatt. We are extrapolating the past trend and we project increasing carbon efficiency, increasingly less reliance on carbon based energy as time goes on. So these are the underlying assumptions in our default projection here. And as we've seen in that default projection which corresponds to business as usual, we're going to be upwards of 700 parts per million by the end of the century. If we're looking to stabilize CO2 concentrations at say 550 parts per million down in here, the purple curve, then clearly we are going to need to change our behavior. We're going to need to change these various terms, some combination of these terms in such a way that we lower CO2 increase and accordingly as the purple curve shows, we would need to produce less carbon free energy in that stabilization scenario in the 550 parts per million stabilization scenario. So we can play around with these numbers and try to figure out how we would actually go about achieving a particular stabilization, how, what terms we might be able to change through a technology and through future policy changes and how those changes would translate to a CO2 emission scenario and our ability to stabilize CO2 concentrations at some particular level. So the next thing we'll do is to play around a little bit with these numbers and see if we might be able to lower our projected CO2 increase from the current trajectory, the business as usual trajectory that has us at 700 parts per million well over twice pre-industrial by the end of the century.