My previous post casually described the major forces that drive energy consumption: Changes in population, changes in GDP and changes in technology.
With all the concern about climate change, people began to look at another measurable change–carbon emissions per unit of energy consumed. This actually is just another way of measuring how technology changes, but it produced another figure for everybody’s charts.
People like Roger Pielke Jr. have highlighted the need to reduce the amount of energy we use to do things–assuming more of us are going to do more things, that seems like a very good and basic idea. Those wishing to follow this subject more closely could do worse than spending serious time at his weblog. Here’s a chart from one of his posts:
This chart basically shows that we are not currently making progress at using less energy to do more things. We’re backsliding. Worse, I’ve done calculations that seem to indicate that we would need to be ‘decarbonizing’ at about 4% a year to make progress on carbon emissions, as opposed to the 0.5% illustrated in Pielke’s chart.
A lot of serious thinking about energy issues has been going on, and some of this thinking led to the creation of a credible equation that showed the relationship between the four variables shown in the quote from Wikipedia below. This equation was called the Kaya Identity. Yoichi Kaya was the economist who expressed it first. Matt Damon has firmly rejected the idea of playing him in the movie.
Just pasting in from Wikipedia here,
“The identity is expressed in the form:
- F is global CO2 emissions from human sources,
- P is global population,
- G is world GDP and g = (G/P) is global per-capita GDP,
- E is global primary energy consumption and e=(E/G) is the energy intensity of world GDP,
- and f=(F/E) is the carbon intensity of energy.
In my work on this blog I tend not to include carbon emissions in my measurements. This is more a philosophical choice than anything else. Everybody on the planet is measuring production of energy, which is why I’m trying to focus on consumption. Carbon dioxide feels like something that is produced, not consumed. Unless you’re a plant.
However, seeing that the main thrust of this blog is to note that population and GDP are rising quickly and leading to greater energy consumption than forecast by the great and the good, for those who agree with my thesis it then becomes very important to look at the role of technology in improving efficiency and lowering CO2 emissions.
If any of you are, like me, concerned about the growth trends I’ve highlighted for energy consumption, you’ll need to use the Kaya identity to puzzle through the consequences. Fortunately, if you’re new to this, a lot of people have been doing a lot of puzzling on the topic for the past couple of decades, so you won’t have to start from scratch.