We are now moving from the physics part of the course to the technology part. There is hopefully a smooth transition. But as I always emphasize, all these parts are linked together, so we should keep the connections in our mind. The first thing as we move to the technology part is to understand and to look at some basic data about emission, current emission, past emission, emission per capita, etc., of energy and energy consumption. The questions we're going to look at in this session is, who is emitting most CO_2? What is emission correlated with? How do we explain variations in emissions for countries which has very similar standards of living? What are outsourced emissions? Finally, where does the energy go? As we shall see, answering this questions is very important. We begin to this graph here, which is extremely interesting. Let me describe the graph. The width on the x-axis, I have the population of the region in questions. The big orange rectangle around two refers to China, and on the x-axis, I look at the population of the country. On the y-axis or the height of a rectangle then tells me how much energy is used per person. The total emission is given by the area of each of these rectangles here. We notice that very obviously and very clearly, there are huge disparities in intensity and in emissions. The Middle Eastern countries, are the countries that have the highest intensity, but since they are thinly populated, they do not contribute a lot of the emission. US as compared to China and India, a relatively small population, but very high-intensity. Then we see a decline on this curve here and we have the Western European countries with the exception of Germany. We'll talk about Germany. Germany is, as you see on the left of China and then United Kingdom, France and other European countries, Italy are on the right of China. We'll understand in a while why this difference. We look at India, India is a huge population, but very low intensity. That is one way to look at the data. This is a similar way, but taking a time dimension into account, and this gives annual total CO_2 emissions by world region. It starts 1750s arbitrarily chosen as the beginning of the Industrial Revolution. The big message here, it gives a time dimension, is that if we look at the total emission from the blue line, which is United States, you see it has remained roughly constant in the last 20, 30 years. Europe's emission has gone down considerably. China's emission has gone up. There is the big message. However, as we shall see, things are not quite as simple, but one thing at a time. This gives the same information about emission per capita, but instead of putting that rectangle graphs, it put it on a traditional map and it puts different colors to show which countries are the hotspot of emission per capita. There are many ways of cutting this information and no single way is right or wrong. Every single way gives a different piece of information. All these things; how much emission is per person, how much is the global emission, how much is the cumulative emission that we're going to see very soon, it all matters a lot when we come to making right decision, equitable decision, fair decisions about who should bear the brunt, who should bear the cost of emission reductions. I'm not going to go into this. My opinions are no better than your opinions, but I want to give you the data on the basis of which you can reach informed opinions. As a first approximation, one important regularity, you see that the higher the income per person of a country, the higher the energy consumption per person. However, there are big variations. Even with countries with high similar incomes, such as US, Germany, France, we have big variation. US and Australia, as you can see, is 16 ton per person. Germany is 10 ton per person. France, very similar in standards of living, geographically continues, similar climate, is roughly half. These tons are tons of carbon, not of CO_2. What explains the difference? Part of the explanation comes, as we shall see now, down to the energy mix, and other part of the explanation comes to the exported emissions, which we'll explain what it is. Let's begin with France. In the case of France, this is how the energy production is split over time. We see this huge, as of now we'd have to call it orange or pink, but you can't miss it. This huge blob, it is nuclear. Lots of the electricity produced in France is produced by nuclear. As you can see, natural gas, oil, and coal are responsible for a very, very small fraction at the bottom. We have some hydroelectric, but the bulk is neutral. Let's look at Germany. It's a very, very different picture. For political reasons where decision has been made to reduce the reliance on nuclear, and we'll discuss in a future session how wise or unwise this decision might be. But the fact is that with nuclear missing, something else has to take the slack in big size, and unfortunately, the slack is taken up by coal, oil, and natural gas. Renewables are substantial and growing quickly, but they're still dwarfed by natural gas, oil, and coal. When it comes, and it is for Germany, to the share of electricity production from fossil fuels, we see the king coal as the lion's share, followed by natural gas and oil. Now we understand why we have such big differences between France and Germany despite very similar standards of living, very similar geographic condition. Let's look at this picture again here. This picture gives annual CO_2 emission. You have very, very dark China because it is a medium intensity and a very large population. In terms of current emission, China is clearly the greatest emission responsible country. However, let us not forget that the population of China is much, much higher than the population of probably the second darkest blob in this chart, which is United States. By the way, I can't do it here, but if you go to the source, which is Our World In Data, you have a cursor at the bottom, which is now on 2017 and you can move it showing how these colors change over time, it is very interesting. Now, what we looked at was annual CO_2 emission, and now we move to the cumulative emission. Why is cumulative important? Well, cumulative is important to break down by countries if you want from an fairness point of view. Again, it goes back to saying, if you are asking different countries to make sacrifices now, well, some countries may say, "Well, is easy for you to tell me to make sacrifices now. You've been emitting for centuries, and now as I am approaching my own industrialization, you're asking me to curb my development." Again, this is a huge discussion. As I said, I don't think that my opinions on this matter anymore valid than yours, but it's important to know the facts. The fact is that, in terms of cumulative emission, the cumulative CO_2 emitted, for instance, by United States, is still much higher than the cumulative emission emitted by China, for instance. By all accounts, Sub-Saharan Africa, with the slight exception of South Africa, is always has emitted and is emitting very, very little. Now, that is in percentage term, the share of cumulative CO_2 emissions. Again, we see that the darkest, more than 50 percent comes from United States, and the second darkest is China, followed by Russia, which is in a way remarkable because the population of Russia is not high. As I said, how much one country emits is only part of a story and actually can be a misleading part of a story. What do I mean? Well, suppose that a country imposes very tough emission limits, but does not curb the import of goods which are very energy-intensive. These goods have to be produced somewhere, and if these goods enter being produced in other countries they might have lower emissions standards than the green country, then the net effect for the planet is negative. If the countries from which goods are imported have lower emission standards than the importing country, the net result for the planet is more CO_2 emitted than if the goods were produced in the original country. The country that is saying, let's not produce these goods anymore looks green but CO_2 molecules don't know about boundaries and CO_2 molecules are universal so if they are produced somewhere else on the planet, well, we're no better off. Typically, one measures CO_2 emissions on the basis of productions. However, statisticians also calculate consumption-based emissions, and these emissions are adjusted for trade. Which means that whenever a good was imported, we need to include all the CO_2 emitted in the production of the good, even if the production occurred in a different country and we have to subtract all the CO_2 emitted in the production of the good which is exported from one country. When we do that, we get a very interesting picture. We get the picture that actually from Russia and from China, there is a substantial outsourcing of emissions. Not surprising. We import huge amounts from China, and therefore, China is, if you weren't emitting on our behalf. All of a sudden, we see that many green European countries, well, are green by the virtue of the fact that they're importing a lot from potentially not very green producers. This is one important aspect of the problem. Let's look at a different aspect, which is also very important because one of the key messages of what I am telling you in this course is that for us to make a difference, we have to engage in what I call a war effort. A war effort entails sacrifices. It is very important to make these sacrifices in a well-directed way, and therefore we have to understand what is our biggest bang for the buck. Where are we spending a lot of CO_2 emissions to do what? This graph here shows that electricity and heat production as the lion share of the CO_2 emissions. Then we have transport and manufacturing industries, roughly the same. Then residential buildings and commercial and public services. Also notice electricity and heat production has had the growing share of our carbon dioxide emission in the world. This final slide presents similar information in absolute terms and not in percentage term as the previous one. The information is roughly the same. The carbon dioxide used for the production of energy plays the lion share. Then we have transport important, agricultural, land, and forestry less important. Residential, private, and commercial is also important. This gives us the initial data. As you know I like to start from the facts on the ground, to move from the science bit to the technology bit and that is what we will be doing in the following sessions.
