Carbon Budgets

by Clive Best, October 3, 2017

It started as a nice simple idea: There is a finite amount of Carbon that humanity can burn before the planet warms above 2C. This idea was based on  AR5  Earth Systems Models (ESMs) ‘showing’ that the relationship between global temperatures and cumulative emissions was linear. At last the IPCC had something easy for world leaders to understand! This was all nicely  summarised in Figure SPM-10, shown below. The Paris accord is essentially derived from this one figure.

The problem though is that it wasn’t really true.