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.
Thus far, I´ve limited myself to counting CO2 molecules. But there´s another issue which seems to impact the RCP8.5 model results: the transient climate response or TCR. The figure below is taken from Climate Lab Book Reconciling Estimates of Climate Sensitivity by Ed Hawkins
This post is one of many discussions about this topic, it´s one of the key issues President Obama got wrong when he said "the science is settled"...when it´s not.
I include it for reference because TCR defines (in the short to medium term) how temperature increases as CO2 atmospheric concentration increases. And the temperature in turn impacts how the carbon sinks sequester CO2. This means a model with a higher TCR will not allow the CO2 to be absorbed by the sinks as well as one with a lower TCR. And as it turns out the IPCC likes to plug in higher TCR´s in most of the model work they use to describe global warming impacts. The difference can be staggering. The IPCC "Business as Usual" case yields a 2 degree temperature increase by around 2055. My emissions profile and carbon sink performance yields 1.4 degrees around 2080. That´s a big difference. Those temperature increases, by the way, are versus the estimated world wide surface temperature "in preindustrial times" which seems to be a moving target. Call it 1750 or 1850, whichever you think looks better.
In conclusion, we can see that RCP8.5 has an extremely high emissions profile, which is deviating from the actual data. It also seems to ignore very real resource limits which are evident to those of us who understand fossil fuels and how they are being depleted. To make matters worse, it essentially chokes the carbon sinks with too much CO2, and this in turn leads to ever higher CO2 concentrations. These very high concentrations are then used to estimate climate parameters, such as temperature and sea level rise, which I believe are exaggerated and way out of line.
These exaggerated values are then used to estimate the benefit from policies such as carbon taxes, renewables entitlements, feed in priorities, World Bank lending practices, and so on and so forth. It´s clear to me we must be highly skeptical about the figures we get from the IPCC, the EU, the USA EPA, and other agencies and private entities which seem to be unable to grasp that their “science” has been trashed.
I´d like to finish by linking a blog post by the Chemist in Langley, which discusses the naming of RCP8.5 as "Business as Usual" in so many publications and scientific papers
"On RCP8.5 and "the Business as Usual" Scenario - Different beasts not to be confused"
The RCP data base
EDGAR 2016 report
Carbon Brief Propaganda Article about 2016 CO2 emissions
Reconciling estimates of climate sensitivity by Ed Hawkins
The implications for climate sensitivity of AR5 forcing and heat uptake estimates
Update of the paper above by Nick Lewis, published as a PDF in his blog
Burn Baby Burn, my blog post about CO2 concentrations written in 2014
Comparing CMIP5 to Observations (note the graph shows all the RCPs, the RCP8.5 values get lost in the crowded field).
On RCP8.5 and "the Business as Usual" Scenario - Different beasts not to be confused