The Keya Identity

The Kaya Identity tells us exactly what families of tools we have in the policy toolbox to reduce carbon dioxide emissions to some desired level. Specifically, carbon dioxide accumulating in the atmosphere can be reduced only by influencing the following four levers. 

1. We could reduce the population. 

2. We could reduce per capita GDP.

3. We could become more efficient. 

4. We could switch to less carbon-intensive sources of energy. 

These are the four—and the only four—means of reducing carbon dioxide emissions. All policies being discussed as climate policies must influence these levers if they are to have an effect. So debates about carbon taxes, cap-and-trade programs, offsets, energy innovation, personal carbon allowances, and on and on must eventually arrive exactly the same place. 

Kaya Identity (1) Carbon Emissions = Population * Per Capita GDP * Energy Intensity * Carbon Intensity

a. P = Total Population b. GDP/P = Per capita GDP (2) GDP = Economic Growth (Contraction) = P * GDP/P = GDP a. Energy Intensity (EI) = Total energy (TE)/GDP = TE consumption/GDP b. Carbon Intensity (CI) = C/TE=Carbon emissions/total energy consumption (3) Technology = “Carbon Intensity of the Economy” = EI * CI = TE/GDP * C/TE = C/GDP

Pielke Jr., Roger. The Climate Fix (p. 71). Basic Books. Kindle Edition. Pielke Jr., Roger. The Climate Fix (pp. 70-71). Basic Books. Kindle Edition

Piekle combines this with his "iron rule" that people will not accept a significant reduction in growth (GDP), let alone "de-growth." There is a very low threshold for the acceptable cost of de-carbonization.

Understanding these rules helps us understand why political pledges never become practical action programs nor to such programs get implemented. In fact, China and India have explicitly said that GDP trumps any effort to de-carbonize.

The Keya identity helps us understand what it would take, for example, to eliminate a given amount of carbon from the world. We can plug in actual numbers and get out actual reductions in specific areas.

I will extend and modify the Keya identity to reflect the increasing difficulty in obtaining raw materials of all kinds, along with assumptions about actual reductions in carbon intensity projected over the next 175 years or so. Political promises are irrelevant. Actual efficiency comes from the replacement of carbon when it makes economic sense. Political "Push back" sets a limit on how fast this can go (The Iron Law.)

Actual decarbonization seems to proceed at a rate of about 1.3% per year. By 2200, this will mean 10% of energy will still be fossil fuels. Of course, GHG warming will have been locked in long before then, probably by 2100. The planet will still warm up, but not at the pace we saw in the late 21st century.

We assume 100 years for modular nuclear technology of some sort to become the accepted, economical, and common way of generating energy, so by 2200, most people will not remember a time when other forms were used. The reason other forms will be replaced is economics. Except in special circumstances, nuclear will be cheaper. Windmills will have mostly vanished by 1250 since they have a lifetime of 20 years. Windmill power generation will have scrap value (copper for the generators and transmission lines from windy places.)

I assume that some form of a portable system will be generated from a nuclear power source. I am skeptical of lithium batteries and hydrogen. I allow for 150 years to develop something better.

I assume a population of 20 million for the region, and 10 million in Calgary.