In the previous postings, the computers predicting global temperatures were shown to be much higher than the actual measured temperatures and that you are not being told that the actual measured global temperatures are currently falling and do not seem to have a link with the rising CO2 accumulating in the atmosphere. This posting looks at the future predictions of global temperatures and how they are biased to make you think they are going to be rising quickly.
To have some understanding how the computers are programed one needs to be acquainted with Equilibrium Climate Sensitivity (ECS) and Representative Concentration Pathways (RCP).
ECS
Firstly, an examination of ECS. The 1979 Charney Report, named for the Chairman of an Ad Hoc group stated:
“We believe, therefore, that the equilibrium surface global warming due to doubled CO2 will be in the range IC to 4C, with the most probable value near 3°C”.
That means, for a doubling of atmospheric CO2, global temperature will rise approximately 1C due to CO2, and the CO2 induced increase in temperature will result in more water vapor. Water vapor is a powerful greenhouse gas. That and some other minor changes in atmospheric gases will result in an additional rise of 2C. Thus, CO2 doubling does not just create 1C rise but rather a 3C rise. They acknowledged that there was a lot of uncertainty about this number. How water vapor and clouds interact are not yet known with any certainty.
Climate sensitivity is expressed two ways. Transient Climate Sensitivity (TCS) is the initial effect of the change in CO2 concentration. ECS does not happen until the oceans heat come into equilibrium with atmospheric heat, for example.
ECS is controversial. There are those that do not believe in the CO2 effect at all. They may not appreciate this postings discussion of ECS and RCP but the posting is addressing what the Alarmists believe. Also, many others buy into the concept but conclude that the effect is much lower than the 3C rise due to a doubling of atmospheric CO2. Down as low as 1C. As well, there are alarmists that use ECS in the 4C range.
As can be seen in the Part 1 posting, the ECS being used has yielded too high of global temperatures.
Tests of the new CMIP-6 climate computer programs conducted by McKitrick and Christy reported: Pervasive Warming Bias in CMIP6 Tropospheric Layers – McKitrick – 2020 – Earth and Space Science – Wiley Online Library
It has long been known that previous generations of climate models exhibit excessive warming rates in the tropical troposphere. With the release of the CMIP6 (Coupled Model Intercomparison Project Version 6) climate model archive we can now update the comparison. We examined historical (hindcast) runs from 38 CMIP6 models in which the models were run using historically observed forcings. We focus on the 1979–2014 interval, the maximum for which all models and observational data are available and for which the models were run with historical forcings. What was previously a tropical bias is now global. All model runs warmed faster than observations in the lower troposphere and midtroposphere, in the tropics, and globally. On average, and in most individual cases, the trend difference is significant. Warming trends in models tend to rise with the model Equilibrium Climate Sensitivity (ECS), and we present evidence that the distribution of ECS values across the model is unrealistically high.”
If you are a climate computer programmer, you can increase the ECS, and it will result in an increase in forecast temperature.
RCP
Representative Concentration Pathway (RCP) is an estimate of the amount of CO2 in the atmosphere at any given time. After studying numerous scenarios, more than the available computer time would allow, they settled on just 5 RCPs.
It is my understanding that the upcoming IPCC’s 6th Assessment Report will use somewhat revised versions of the original 5 pathways. These revisions are to accommodate current thinking about the options and potential pathways. Only RCP 8.5 remains as orginally conceived. At least one of the pathways will meet Paris Agreement goal of of keeping global temperature rise below 1.5C . In between 1.5 and 8.5are three others that do not meet the objective but are considered potential outcomes depending on mitigation policies. The pathways keep track of the forecast fossil fuel emissions of CO2” versus “years” beginning at the current time continuing out to the year 2100.
The alarmists and many other warmers are using RCP8.5 as Business As Usual. Most are not notifying the reader that the forecast CO2 in the atmosphere for their predicted temperatures is the HIGHLY UNLIKELY pathway. Some postings have said that it is physically impossible, requiring such things as all the minable coal would have to be burned. What does this amount to? The alarmists are using the Highest CO2 concentration. They are also using a Equilibrium Climate Sensitivity that historically is too high. This combination will deliver Highly Unlikely predicted global temperatures. They need to scare you into going along with the alarmist’s program.
Some scientists and engineers do not believe that carbon dioxide emissions and other so-called greenhouse gases are causing global temperature to rise. My guess is that most of the scientists and engineers believe that those gases do influence the globe’s temperature. Within the believing group, however, there is a divide as to how much temperature rise can be attributed to the greenhouse gases. (Your host, cbdakota, is an agnostic skeptic that believes that on-the- whole, the sun is in control).
From a recent Dr. Roy Spencer blog:
“Yes, more CO2 must produce some warming. But the amount of warming makes all the difference to global energy policies.
Seldom is the public ever informed of these glaring discrepancies between basic science and what politicians and pop-scientists tell us.
Why does it matter?
It matters because there is no Climate Crisis. There is no Climate Emergency.
Yes, irregular warming is occurring. Yes, it is at least partly due to human greenhouse gas emissions. But seldom are the benefits of a somewhat warmer climate system mentioned, or the benefits of more CO2 in the atmosphere (which is required for life on Earth to exist).
But if we waste trillions of dollars (that’s just here in the U.S. — meanwhile, China will always do what is in the best interests of China) then that is trillions of dollars not available for the real necessities of life.
Prosperity will suffer, and for no good reason.“
Now take this to your children to read.
cbdakota
Climate Change Sanity 
