Posted: Jun 11, 2019 1:02 pm
by Thommo
If anyone's interested the methodology for the image is described here: ... wes-582545 ... sequence=2
Each (elastic) distribution index is then converted into a synthetic emissions distribution (giving the emissions associated with each income percentile) by multiplying the average national (or global) per capita emissions by each percentile’s index value divided by the distribution’s average index values [A, F]

The resulting emissions distributions, while faithful to the underlying income distributions, in many cases produce per capita emissions values at the lower end of the distribution (i.e. associated with the poorest segments of the population) that are lower than might be considered plausible. For example, unless living a subsistence life completely off-grid using only renewable energy, each person will have a base level of emissions resulting from their energy use that, in some cases, may be higher than suggested by the distribution. The lower bound of plausibility will differ by country and will be dependent on the structure of that nation’s economy and fuel mix used for energy provision. As a result, for these indicative calculations, a nationally determined threshold of minimally plausible emissions is applied, below which no percentile’s per capita emissions can fall.

To paraphrase, they apportioned carbon emissions within countries on a 1 for 1 basis with income and then fudged the bottom end a bit.