It was not easy, but the new IPCC Summary for Policymakers manages to outdo itself in nuttiness. They have rebirthed some really bad old stuff and combined it with even worse new stuff.
Here is the best of the worst.
The “hockey stick” is back! I am not kidding. In fact a new version (but still the hockey stick) is the very first thing you see, Figure 1a. There is a hint of the little ice age but no Medieval or Roman warm periods, which may have been even warmer than today. So the handle now sags a bit over the last 1000 years then shoots almost straight up in the modern blade. That blade is of course the scary warming. A fine piece of old junk, reborn.
The hockey stick deception called “hide the decline” has not changed. The declining handle is kluged to the supposedly rapid modern warming. Not shown is the fact that the proxy measurements in the handle continue their decline during the modern period. Plus I am told that this figure does not appear in the humongous full report. If so then it is doubly deceptive.
Figure 1b is my personal favorite and has been for a long time because it makes the fallacy of alarmism crystal clear. It shows the supposedly observed global temperatures since 1850 plus two climate model computer runs. One run includes both human and natural “factors” while the other only includes natural stuff. Not surprisingly the natural one shows no warming while the human driven one matches the so-called observations.
What makes this so silly is shown in Figure 2, which lists all of the “drivers” of temperature change used in the model. All are human! Obviously if all of the drivers are human then all the warming must be human, right? But this is an assumption, not an outcome. So Figure 1b, the supposed proof that the warming is caused by humans, is merely restating the assumptions built into the model. The reasoning is perfectly circular.
In short the IPCC’s nutty argument goes like this: “Assuming all warming is caused by humans we find that all the warming has been caused by humans.”
Of course the alarmists do not get the joke because they believe that all warming is indeed caused by humans. Plus the circular argument is not stated in these simple terms.
Note that I refer to the global temperatures since 1850 as “supposedly observed”. There was no way to observe global temperatures until 1978 when we launched satellites that do that. The temperatures shown are actually arcane statistics produced by a highly questionable computer model. They are not observations.
Even worse, the temperatures found by the satellites bear no resemblance to these computer generated statistics. In fact the satellite observations show no human warming at all. Of course these are not considered by the IPCC.
As I recall, this circular argument first appeared 20 years ago in the Third Assessment Report. It has been whinnying with us every Report since. The hockey stick is of a similar ancient vintage.
Newer, but still old, is the outlandish human emissions scenario known simply as 8.5, which I think first appeared 8 years ago in AR5. It assumes a preposterous amount of CO2 emissions through 2100, as shown in Figure 4.
This scenario has been heavily criticized, but here it is again. The emission scenarios are what drive the future warming projections of the models and scenario 8.5 creates a dangerous amount of future warming. This is just what the alarmists need to drive their political and social change agendas. Moreover, unlike past ARs in this case the IPCC does not say which scenario is most likely. This leaves the monster 8.5 as likely as any other and I am sure it will be prominently featured in follow up studies. It is heavily featured in this SPM because it drives the greatest threat..
Not content with these old time scare drivers, AR6 introduces a new one, which even some top alarmists find “insanely scary and wrong”. This new foolishness is the new wave of hot models. My last CFACT article was about this issue. See my “Climate modeling civil war?”
The climate modeling that the IPCC uses is actually done by a lot of different government modeling centers around the world. About 100 models are involved. For reasons that are still a well kept secret, roughly half of these models ran much hotter for AR6 than they did for AR5.
We know how the models were changed, but not why. Given that they were all juiced up the same way, my thought is that there was a coordinated effort to make things much scarier. Why else do it? The change was sure to make the models hotter, so this was a deliberate and coordinated choice.
And scarier they certainly are. Combined with the absurd scenario 8.5 we read on page 18 that we might get up to a whopping 5.7 degrees C of warming by 2081-2100, which is only 60 short years away.
So there you have the basic silly reasoning. The hockey stick falsely says the recent warming is unprecedented, rapid and big. The models, which are programmed so that only humans can cause warming, falsely say that humans are causing this warming. Wacky scenario 8.5 combined with the newly hot models falsely says it could get very, very hot, causing all kinds of bad stuff.
That is the basic reasoning, from the hockey stick to insanely hot models, and science it ain’t.
The rest of the 41 page Summary for Policymakers is just a whole bunch of specific scary futures based on the models. Projecting this, that and other nasty changes, over various times, including regionally. Endless woe to come.
Given that the models are ridiculously biased these scary forecasts are of little interest.
They have outdone themselves on the main report, which is almost 4,000 pages long instead of the usual 1,000. But since it is just the “humans cause everything bad” nonsense in great detail, it is not worth reading. The Summary tells us all we need to know. The IPCC report is wrong.
Climate science is so politicized that it is useless. A nutty fallacy carried to extremes by computer modeling.