This page is written to document the differences between the IPCC´s AR5 RCP8.5 Pathway (the one that´s called “Business as Usual” in IPCC propaganda and most media), and my estimate of emissions and CO2 concentration, which I documented partially in a post called “Burn Baby Bun" written in 2014.
The following graph shows emissions resulting from all anthropogenic factors (fossil fuel burning, cement, land use change, etc):
There´s a slight difference between the emissions shown in this graph and the one in my referenced post: I added the cement manufacture and other inferred from the difference between the EDGAR data base and the CMIP data, and extrapolated from 2015 at a constant value (1.33 Billion metric tonnes, where billion is the European convention, or 10 to the 12th).
As we can observe in the graph, my estimate and RCP8.5 are both above the EDGAR actual value in 2015. It´s possible that EDGAR´s report only includes emissions from fossil fuel use, and it´s missing the other anthropogenic factors (the EDGAR report writing style could use some improvements).
Both RCP8.5 and my estimate climb over time (which may be an erroneous assumption given that CO2 emissions appear to have stabilized). However, by 2040 they show a large difference, because the IPCC team assumed the amount of fossil fuels resources was essentially endless, and that alternative technologies wouldn´t have much of an impact (this of course renders RCP8.5 less than worthless as a “Business as Usual Case”). On the other hand, I prepared a model which cut back on fossil fuel use because its price was increasing and this discouraged demand (it assumes something else intrudes in the market to replace fossil fuels as they become less competitive).
The following graph shows the CO2 concentration difference between the RCP8.5 and my estimate:
The key differences between the two are the emissions volume, and the carbon sink efficiency. RCP8.5 has a huge emissions increase, which in turn increases atmospheric concentration to very high values. The CO2 concentration extreme causes a large temperature increase, and the overall effect of the two exaggerated values reduces the carbon sink ability to sequester CO2. This of course causes a larger increase in CO2 concentration as a function of emissions.