One of the issues that Michael Finus discussed last Tuesday night in his I-SEE seminar was the Kaya Identity, which is an equation relating to human impact on climate. I had not come across it before – such a sheltered life!
The idea is that total emission levels can be set out as the product of four inputs: population, GDP per capita, energy intensity (per unit of GDP), and carbon intensity (emissions per unit of energy). It's a version of the I = PAT equation (which I had heard of).
It can be written: F = P x G/P x E/G x F/E where:
- F is CO2 emissions
- P is population
- G is GDP, and
- E is energy consumption
- G/P is a measure of affluence
- E/G is energy intensity, and
- F/E is carbon intensity
It can apply to nations and globally, and I wrote about carbon intensity last October. This was one of the less gloomy parts of the talk.