You might wonder, why are we talking about sustainability and energy and a course on public health. Actually, it turns out all of these topics are intimately related. In this module, I'm going to set you up with an introduction to use of energy on this planet as an introduction to subsequent modules, where we'll focus more on the impacts of energy on public health. I'd like to begin by talking about global energy consumption on our planet here. The bad news is our energy consumption is projected to grow by 56 percent between the years 2010 and 2040. A very small fraction of that growth is going to happen in OECD countries in other words countries that belong to the Organization for Economic Cooperation and Development. These are typically higher income countries and the vast majority, maybe 90 percent of growth is going to happen in non-OECD countries. The graph here illustrates that concept. What we're looking at is world energy consumption by country grouping across different years. The bars in blue here represent the OECD countries at which the United States is one. The red represents non-OECD countries in Asia. I'll just call these Asian countries going forward and then the bronze, our other non-OECD countries outside of Asia, so I'll call those non-Asian countries. If we look at 2015 on the left, you can see that in that year, the OECD countries used by far the most power of any of these country groupings, followed by the Asian countries, followed by the other non-Asian, non-OECD countries. But as we fast forward in time to about 2025, you can see that these non-OECD Asia countries are going to catch up with the OECD countries and by the time we get to 2040, the non-OECD Asia countries are going to be leading the world in terms of energy consumption, followed by the OECD, followed by the non-OECD, non-Asian countries. If you look across the blue bars at all years, you see the blue bars are relatively stable, not much growth happening there. It's really these Asian countries that are going to be driving the growth in energy consumption. Where are we getting this energy from? The graph I'm going to describe here, looks at energy use in terms of a unit called Mtoe, or millions of tons of oil equivalent. We can look at energy from a lot of different sources, but we standardize it to oil so we can compare apples to apples. This graph is comparing or following the trends between 1971 and 2015 for a number of different sources. Let's look at each of them. On the bottom of the graph we're looking at coal in red and you can see our coal use has actually increased over time. In green, we have oil and oil use has been relatively stable and even declined slightly over this period. In dark blue, we have natural gas, and you can see natural gas usage has increased. In orange we have nuclear and there's been very modest increases in nuclear, hydropower in purple has been relatively static and biofuels and waste have also been relatively stable over time. I want to finish by talking about a concept called the energy ladder, and we're looking at a graphical representation of that here. On the X-axis, we're looking at income of a population using energy from very low on the left to very high on the right. Then as we go up the Y-axis, we're having energy sources that are cleaner and more efficient and more convenient fuels to use specifically for cooking. If we start at the lower left corner of the graph, the very most basic fuel that humans have used in our history is burning crop waste and dung. That's where we would see a very low population using that energy source. Wood, the next rank up the energy ladder is used by very low, all the way up to middle income populations. Charcoal is above that, and now we've moved into more of a low to middle income population. Then coal is following that the next rank up, and that's more of a middle income population. You'll see a dashed line here between coal and kerosene, that's the dividing line between solid fuels at the bottom of the graph and non-solid or liquid fuels at the top. Above coal we can see kerosene, which is another middle income now non-solid fuel. Above that is ethanol and methanol, as well as gas and liquefied petroleum gas and those are both middle to high income fuels. Then by the time we get to our highest income populations, we have two primary sources of energy, natural gas, and electricity. Hopefully this module has given you a better sense of how we use energy in the globe, and again has set us up for subsequent discussions about the impacts on public health from our energy use choices.
