The first lesson has some background on the energy problem. I have the carbon graph, showing the emissions taking off around 1800, driven by a smooth exponential growth in coal production. Actually the coal was not really being produced—that happened back in the carboniferous period 300 million years ago—it was being moved around and then burnt. The graph shows oil starting, then gas a little later, each in its own exponential variant. Meanwhile, the emissions from coal have still been increasing.
I've been saying "until this year" with a quizzical optimism, and finally it looks like "production" of coal is down, which is a sign that we will eventually burn less of it.
This graph from BP is still pretty scary. That gray coal line definitely seems to be getting thicker. Also alarming is the sandy bit at the bottom, which is biomass. Before coal that was the only source of heat, and it was more or less constant until the middle of the twentieth century. Now that is on the rise. I'm not sure how much is in industrial use of biomass, for example replacing coal in thermal power stations, and how much is domestic use from fuel-poor burning what they can find.
If you look carefully you can see the thin yellow strip of renewables at the top, like a sprinkling of snow on a mountain top. While this has increased from its previous levels of invisible and insignificant, it is still a long way off replacing any of the behemoths beneath it.
It should be noted that while BP's data can probably be trusted, their main business is still in selling fossil fuels, and their business model is still based on selling more. The graph goes up to 2013.
The next graph is from the International Energy Agency, and gives us hope that 2013 was around the high point of coal, with production in China and the OECD decreasing. It's tempting to see that as a peak, and look forward to a steady then rapid decline in coal extraction.
However, Dick Van Dyke nostalgia has been strong in the US, and production was up last year. So, once again, it's too early to tell.I guess it depends on who wins between the people selling fossil fuels, and people promoting energy efficiency and renewable energy.
While checking figures, I also revised the proportion of Japanese energy that is imported from 80% up to 90%. The lower figure was pre-Fukushima, which had got into my slides at the beginning, and I've now corrected several years late. (Japan was 20.2% energy self-sufficient in 2010, and 8.3% self sufficiency in 2016 according to METI.)
I had been telling student that Japanese houses use 30% of the country's total energy, while in fact its more accurate to say that buildings in Japan use around 30% of the total energy.
Whichever way you look at it, the amount of energy imported can be reduced if we get serious about low energy buildings.
I also found some interesting changes in energy use, which I may need to mention some time, although should probably work out more carefully first.
Between 1973 and 2015, residential energy use in Japan increased by 90%, office energy use increase by 140% and industrial energy reduced by 20%.
I'm not sure to what extent this is a sign that houses and offices have become much less efficient, while industry has become more efficient, or whether it shows that Japanese industry is producing less, and people are spending more time in offices and more money on energy-consuming appliances in their houses.
(Dick Van Dyke from trailer screenshot - Mary Poppins Trailer, Public Domain, https://commons.wikimedia.org/w/index.php?curid=34700974)
