Climate alarmists and their biased models
Image: John Christy / UAH
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.
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.
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
RCP is an estimate of the amount of CO2 in the atmosphere. After studying numerous scenarios, more than the available computer time would allow, they settled on just 5 RCPs..
The upcoming IPCC’s 6th Assessment Report will use the chart below. Its focus being “global fossil fuel emissions of CO2” versus “years” beginning at the current time continuing out to the year 2100. The origninal 5 RCPs have been change somewhat to match Paris Agreement objectives and renamed.
Three RCP are considered Likely-Given current policies. One meets the Paris Agreement’s proposed no more than a 1.5C rise by 2100. The other two fail. One achieves “modest mitigation” but the increase in temperature is 2.5C. The other one is of “weak mitigation” allowing a temperature rise of 3C.
Remember these are LIKELY according to the IPCC.
The 4th plot is described as Unlikely because of reversal of some current policies. It results in a temperature rise of 4C.
Finally, we have the 5th plot which is described as Highly Unlikely. It observes that it is often wrongly used as Business as Usual. And that it is the replacement for RCP 8.5i
The notations of “Currently policies” and “Pledged policies” are another revelation, but they will be discussed in another posting.
Image: Nature
The alarmists and many other warmers are using RCP8.5 (aka SSP5-8.5) as Business As Usual.
Most are not notifying the reader that the forecast CO2 in the atmosphere for their predicted temperatures are 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).
See more here: cbdakota.wordpress.com
PSI editor’s note: The Slayers believe carbon dioxide has NO effect on temperature, as every ice core shows temperature changing BEFORE a change in CO2, NOT after it, but we present this article in the spirit of fairness.
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Jerry Krause
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Hi cb, Andy, and John
Good article cb, not a repeat of what others have written.
And thanks Andy and John O’ for making the effort to allow Readers of PSI to consider what cb has written.
Have a good day, Jerry
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Andy
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Cheers Jerry, we appreciate your kind words 🙂
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Herb Rose
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Water is not a greenhouse gas warming the Earth but a cooling mechanism where heat is absorbed from the Earth and carried into the atmosphere and released by condensation to be radiated into space. Given the solubility of CO2 in water the greater the water in the atmosphere the less CO2 gas is in the atmosphere. The whole global arming/climate change scenarios is based on stupidity not science.
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James McGinn
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With the exception of its surface, where the molecules are bound to each other, liquid H2O has a high degree of elasticity and this is what underlies its capacity to absorb thermal energy and constantly re-release it at a constant rate. We can think of H2O as being trillions and trillions of little pendulums. It will heat anything cooler than it and cool anything hotter than it (no phase change required/necessary). Consequently it is constantly moderating temperature extremes.
It is interesting to note that when H2O nanodroplets are small, as is the case upon first evaporating, their heat capacity is lesser than when, at higher altitude, the droplets combine to make larger droplets. This is because smaller droplets have relatively more surface than do larger droplets and surface of liquid water does not have a high heat capacity because the molecules on the surface, have greater polarity, are more tightly bound to one another.
James McGinn / Genius
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Jerry Krause
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Hi James and hopefully other PSI Readers,
James: “It is interesting to note that when H2O nanodroplets are small, as is the case upon first evaporating, their heat capacity is lesser than when, at higher altitude, the droplets combine to make larger droplets.”
And your reference to this measurement is???
Have a good day, Jerry
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Jerry Krause
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Hi cb and hopefully PSI Readers,
I just made a terrible mistake. In submitting a comment relative to James’ comment, I submitted it to (https://principia-scientific.com/meet-zhurong-china-names-mars-rover-after-fire-god/).
We (James, Herb, and I) have continued what I consider a very informative conversation relative to ‘fundamentals of SCIENCE’ which was begun here and I hoped would continue here. But the plans of mice and men go astray.
Have a good day, Jerry
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