Reposted from Dr. Roy Spencer’s Blog
September 8th, 2019 by Roy W. Spencer, Ph. D.
It’s been ten years since I addressed this issue in a specific blog post, so I thought it would be useful to revisit it. I mention it from time to time, but it is so important, it bears repeating and remembering.
Over and over again.
I continue to strive to simply these concepts, so here goes another try. What follows is as concise as I can make it.
- The temperature change in anything, including the climate system, is the result of an imbalance between the rates of energy gain and energy loss. This comes from the First Law of Thermodynamics. Basic stuff.
- Global warming is assumed to be due to the small (~1%) imbalance between absorbed sunlight and infrared energy lost to outer space averaged over the Earth caused by increasing atmospheric CO2 from fossil fuel burning.
- But we don’t know whether the climate system, without human influence, is in a natural state of energy balance anyway. We do not know the quantitative average amounts of absorbed sunlight and emitted infrared energy across the Earth, either observationally or from first physical principles, to the accuracy necessary to blame most recent warming on humans rather than nature. Current best estimates, based upon a variety of datasets, is around 239-240 Watts per sq. meter for these energy flows. But we really don’t know.
When computer climate models are first constructed, these global-average energy flows in and out of the climate system do not balance. So, modelers adjust any number of uncertain processes in the models (for example, cloud parameterizations) until they do balance. They run the model for, say, 100 years and make sure there is little or no long-term temperature trend to verify balance exists.
Then, they add the infrared radiative effect of increasing CO2, which does cause an energy imbalance. Warming occurs. They then say something like, “See? The model proves that CO2 is responsible for warming we’ve seen since the 1950s.”
But they have only demonstrated what they assumed from the outset. It is circular reasoning. A tautology. Evidence that nature also causes global energy imbalances is abundant: e.g., the strong warming before the 1940s; the Little Ice Age; the Medieval Warm Period. This is why many climate scientists try to purge these events from the historical record, to make it look like only humans can cause climate change.
I’m not saying that increasing CO2 doesn’t cause warming. I’m saying we have no idea how much warming it causes because we have no idea what natural energy imbalances exist in the climate system over, say, the last 50 years. Those are simply assumed to not exist.
(And, no, there is no fingerprint of human-caused warming. All global warming, whether natural or human-caused, looks about the same. If a natural decrease in marine cloudiness was responsible, or a decrease in ocean overturning [either possible in a chaotic system], warming would still be larger over land than ocean, greater in the upper ocean than deep ocean, and greatest at high northern latitudes and least at high southern latitudes).
Thus, global warming projections have a large element of faith programmed into them.
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The fact that the climate simulations have warming caused by increased amounts of CO2 hard coded in means that they beg the question as to whether CO2 causes warming. So in trying to answer the question, does CO2 cause warming, the simulations are useless. They are of no value.
Well said Dr Spencer.
Another way of saying it:
Climate sensitivity to CO2 is an input to the climate models, not an output.
The models don’t provide any real insight into our climate system. They simply tell us the planet will get warmer if we assume that CO2 causes warming and then we add lots of CO2. Isn’t climate science wonderful?
I guess that’s why the model closest to observations assumes the least climate sensitivity to CO2.
Dr. Spencer, thank you. That is an excellent and concise presentation.
I think Dr. Spencer’s article outlines the uncertainties of current day climate science very well.
We shouldn’t be spending Trillions of dollars to fix a CO2 “problem” with this level of uncertaintly as to whether it is a problem or not.
“The temperature change in anything, including the climate system, is the result of an imbalance between the rates of energy gain and energy loss. This comes from the First Law of Thermodynamics. Basic stuff”
Basic stuff. Still FALSE. The first law of thermodynamics is about energy, not temperature. Confusing temperature with the total energy is so typical for climastrology.
One can have an isolated system, no energy gain, no energy loss, which has a change in temperature. It can be a chemical process inside the system, for example, that does it.
“And, no, there is no fingerprint of human-caused warming. All global warming, whether natural or human-caused, looks about the same. If a natural decrease in marine cloudiness was responsible, or a decrease in ocean overturning [either possible in a chaotic system], warming would still be larger over land than ocean, greater in the upper ocean than deep ocean, and greatest at high northern latitudes and least at high southern latitudes”
The models themselves have been shown — positively and without any doubt whatever — to produce chaotic output when run over 50 or 100 year time scales. The paper proving this is from NCAR/UCAR . I wrote about this at Climate Etc. A model run 30 times, “[T]he scientists modified the model’s starting conditions ever so slightly by adjusting the global atmospheric temperature by less than one-trillionth of one degree”…. and produced 30 hugely different, contradictory, 50 year projections of North American winters. See image here.
The climate, as a physical system, is and has been known to be “a coupled nonlinear chaotic system” as acknowledged by the IPCC.
It is exceeding difficult (approaching impossible) to quantitatively tease out tiny contributing effects — such as the influence of increasing atmospheric CO2 or that of ocean overturning or changing marine cloudiness — from such a system.
How odd that, as skeptics, we find ourselves identifying with the Imperial Officer here. And, as we’ve seen, if you question the dogma, your “lack of faith” will be punished by the establishment.
rip
Forgive me if this is nonsense. Dr Spencer’s recent post on GCMs
https://wattsupwiththat.com/2019/09/08/the-faith-component-of-global-warming-predictions/
claims that when the models are first constructed a multiplicity of energy imbalances lead to warming or cooling. These are “processed” so that over, say, a hundred years they result in net zero change. Then the CO2 warming is introduced. Clearly the processing removes competing effects and makes all warming due to CO2.
This is obviously not science as we know it. Could Dr Frank’s approach show what happens when the CO2 signal has to compete with all the other imbalances including the uncertainties about their magnitudes and influences? Could Dr Spencer’s point be that this uncertainty does not arise with GCMs because they are processed to neutralize effectively the imbalances that inconveniently interfere with the CO2 alleged dominance?