Guest essay by Eric Worrall
We laughed when Alexandria Occasio Cortez claimed that the world would end in 12 years. According to a new climate study, AOC is an optimist; we might only have seven years. But the authors appear to make some fairly pessimistic assumptions to achieve that prognosis.
Climate change: Threshold for dangerous warming will likely be crossed between 2027-2042
Scientists introduce a new way to predict global warming, reducing uncertainties considerably
Date: December 21, 2020
Source: McGill UniversityThe threshold for dangerous global warming will likely be crossed between 2027 and 2042 — a much narrower window than the Intergovernmental Panel on Climate Change’s estimate of between now and 2052. In a study published in Climate Dynamics, researchers from McGill University introduce a new and more precise way to project the Earth’s temperature. Based on historical data, it considerably reduces uncertainties compared to previous approaches.
…
“Climate skeptics have argued that global warming projections are unreliable because they depend on faulty supercomputer models. While these criticisms are unwarranted, they underscore the need for independent and different approaches to predicting future warming,” says co-author Bruno Tremblay, a professor in the Department of Atmospheric and Oceanic Sciences at McGill University.
Until now, wide ranges in overall temperature projections have made it difficult to pinpoint outcomes in different mitigation scenarios. For instance, if atmospheric CO2 concentrations are doubled, the General Circulation Models (GCMs) used by the Intergovernmental Panel on Climate Change (IPCC), predict a very likely global average temperature increase between 1.9 and 4.5C — a vast range covering moderate climate changes on the lower end, and catastrophic ones on the other.
A new approach
“Our new approach to projecting the Earth’s temperature is based on historical climate data, rather than the theoretical relationships that are imperfectly captured by the GCMs. Our approach allows climate sensitivity and its uncertainty to be estimated from direct observations with few assumptions,” says co-author Raphael Hebert, a former graduate researcher at McGill University, now working at the Alfred-Wegener-Institut in Potsdam, Germany.
…
Read more: https://www.sciencedaily.com/releases/2020/12/201221160425.htm
The abstract of the study;
An observation-based scaling model for climate sensitivity estimates and global projections to 2100
Raphaël Hébert, Shaun Lovejoy & Bruno Tremblay
Climate Dynamics (2020)
Abstract
We directly exploit the stochasticity of the internal variability, and the linearity of the forced response to make global temperature projections based on historical data and a Green’s function, or Climate Response Function (CRF). To make the problem tractable, we take advantage of the temporal scaling symmetry to define a scaling CRF characterized by the scaling exponent H, which controls the long-range memory of the climate, i.e. how fast the system tends toward a steady-state, and an inner scale 𝜏≈2τ≈2 years below which the higher-frequency response is smoothed out. An aerosol scaling factor and a non-linear volcanic damping exponent were introduced to account for the large uncertainty in these forcings. We estimate the model and forcing parameters by Bayesian inference which allows us to analytically calculate the transient climate response and the equilibrium climate sensitivity as: 1.7+0.3−0.21.7−0.2+0.3 K and 2.4+1.3−0.62.4−0.6+1.3 K respectively (likely range). Projections to 2100 according to the RCP 2.6, 4.5 and 8.5 scenarios yield warmings with respect to 1880–1910 of: 1.5+0.4−0.2𝐾1.5−0.2+0.4K, 2.3+0.7−0.52.3−0.5+0.7 K and 4.2+1.3−0.94.2−0.9+1.3 K. These projection estimates are lower than the ones based on a Coupled Model Intercomparison Project phase 5 multi-model ensemble; more importantly, their uncertainties are smaller and only depend on historical temperature and forcing series. The key uncertainty is due to aerosol forcings; we find a modern (2005) forcing value of [−1.0,−0.3]Wm−2[−1.0,−0.3]Wm−2 (90 % confidence interval) with median at −0.7Wm−2−0.7Wm−2. Projecting to 2100, we find that to keep the warming below 1.5 K, future emissions must undergo cuts similar to RCP 2.6 for which the probability to remain under 1.5 K is 48 %. RCP 4.5 and RCP 8.5-like futures overshoot with very high probability.
Read more: https://link.springer.com/article/10.1007/s00382-020-05521-x
From the study;
… For the high-emission scenario RCP 8.5, all methods show a high probability of a warming exceeding 2 K before 2100. According to the SCRF, the risk of overshooting 1.5 K is negligible before 2024 (or 2028), but extremely likely after 2036 (or 2047), similarly to the CMIP5 MME which reaches the 95% probability of overshooting 1.5 K in 2038. The 2 K threshold is also extremely likely to be crossed about 15 years later in 2055 for both the SCRF and CMIP5 MME (or 2068). …
Read more: Same link as above
The study authors appear to estimate a fairly low transient climate response, but a potentially high end equilibrium climate sensitivity.
… Our analysis supports better constrained TCR and ECS likely range than the IPCC AR5. When using 𝐹𝐴𝑒𝑟𝑅𝐶𝑃FAerRCP (or 𝐹𝐴𝑒𝑟𝑄𝑎FAerQa), the range shrinks from [1.0, 2.5] K to [1.4, 2.0] K for the TCR (or [1.2, 1.5] K) and from [1.5,4.5]𝐾[1.5,4.5]K to [1.8,3.7]𝐾[1.8,3.7]K for the ECS (or [1.5, 2.7] K); the median estimates also decrease from 1.8 K to 1.7 K (or 1.4 K) for the TCR and from 3.0 K to 2.4 K (or 1.8 K) for the ECS. This agrees with other recent observation-based studies (Otto et al. 2013; Skeie et al. 2014, and Johansson et al. 2015) which also support a downward revision of the ECS upper 17% bound by at least half a degree. In addition, the ECS500500 was found to be significantly smaller, 2.2+0.6−0.5𝐾2.2−0.5+0.6K (or 1.7+0.4−0.2𝐾1.7−0.2+0.4K), than the ECS. This implies that if the ECS is on the higher end of the CI, then a large fraction of the warming would be experienced hundreds of years after a potential stabilization of anthropogenic forcing. An important and rather conservative claim supported by this evidence is therefore that the upper 5% ECS bound and median of AR5 can be safely revised downward to 4.0 K and 2.5 K. The lower 5% bound of 1.5 K, on the other hand, remains reliable. …
Read more: Same link as above
Interestingly the TCR (Transient Climate Response) estimated by the authors appears to be fairly close to the ECS (Equilibrium Climate Sensitivity) estimated by Lord Monckton in his corrected feedback study. The authors of this study justify this difference between TCR and ECS by raising the possibility that the climate will take a long time to stabilise (“hundreds of years”) even if anthropogenic CO2 emissions were halted today, so a lot hinges on how much warming is still in the pipeline.
How can we get an estimate to constrain the ECS, without waiting for centuries for the climate to finish responding to anthropogenic CO2 emissions? One option is to consider past geological periods such as the Jurassic (1950ppm CO2, +3C global warming). If 1950ppm CO2 can only raise global temperature by 3C, even when the paleo-climate had millions of years to respond to elevated CO2 levels, this implies that ECS is small, and there is very little if any additional warming waiting in the pipeline. A low ECS implies that any anthropogenic global warming likely to occur as a result of our burning of fossil fuel is a total non event – we will run out of fossil fuel long before we reach 1950ppm. But this viewpoint does not appear to be popular with most government funded climate scientists.
Criticism of supercomputer models is unwarranted?
Are they serious?
Well you can’t depend on real data, it doesn’t always agree with the meme.
Perhaps not, but when it comes to social control and stripping your personal wealth, they are deadly serious.
“I own nothing, I have no privacy and life has never been better.”
To bee or not to bee, that is the question.
Do stop droning on, shrnfr
>:P
Whether ’tis nobler in the mind to suffer the slings and arrows of outrageous forecasting.
What’s all the Buzz about?
I have no idea what they’re smoking.
Don’t you mean “Not The Bee”?
But the paper has something for everybody. It also says “Our new approach to projecting the Earth’s temperature is based on historical climate data, rather than the theoretical relationships that are imperfectly captured by the GCMs.”
DNR, shirley that is only a throw-away line, as the “historical climate data” shows 50 meters higher and 150 meters lower sea levels as “historical climate data” to go along with CO2 variance at least an order of magnitude. Eric W. has become quite the expert at findings political scientists willing to be-clown themselves, but then, it is a target-rich environment.
Yes, most of them are adding the letters CS to their CV hoping nobody discovers it’s an attempt to hide Climate Scientist as their specialty in geography.
What they are saying is that previous climate models were JUNK.
Well, YES.. we know that
Trouble is, this one is no better. !
Looks like 𝐹𝐴𝑒𝑟𝑄𝑎FAerQa News to me.
Hey, it’s like voter fraud. You do not have to provide any counter argument you just repeat every day a spurious fallacy like ” these criticisms are unwarranted”. That’s enough, after all logic and science is just a manifestation of white privilege and should be shunned.
So please check your privilege, wind in your white supremacy talk and stop contracting all these well founded emotional arguments. That’s enough cis-gender patriarchy for one day, thank you.
The models show what they were designed to show. How could they possibly be in error? /src
When the estimation variance is triple the estimate, forgive me for worrying.
I’ll just laugh in comic relief, instead.
I’m still waiting for these “climate scientists” to embrace the extraordinarily high estimation variances associated with their “supercomputer-generated models” as justified criticism.
Maybe they’re so unfamaliar with statistics that they think the higher the estimation variance, the better their models are. My only response is “Sheesh!”
By the way, I saw no mention of the estimation variance associated with this new-fangled model, but why confront a new idea with reality, right?
Hilarious, aint it? Soon you will be censored for making fun of their utterly failed predictions and secret peer reviewed modeling data. Data that David Evens has openly challenged any warmist wannabe into putting their inputs, suppositions etc through his vastly superior models and see what comes out….challenge denied.
So if they are not confident enough in their models that they would want them to be examined by the best….well then…screw you!
Could, Would and Should are such important words in climate models.
A global temperature rise of 1.9 and 4.5C is going to be catastrophic?
I must be dead then, and just don’t know it!
Quite apart from the variation in day/night temperatures, when I travel between England and Scotland, only 400 miles or so, the temperature between the two is consistently around 5C.
No catastrophe so far, so I must be dead.
I used to work on the fringes of Detroit and lived in the northern suburbs. The difference was consistently about 3 degrees on my drive to work and back home. I went through that temperature change twice a day for years and am still here to talk about it.
The heat island effect in the city I live in is about 2C. I measured this consistently, sometimes daily. That ‘warming’ didn’t kill anybody, it’s largely beneficial. In fact, at this moment we would benefit greatly of some 15C of ‘global warming’ here. Or more, if possible.
Better not let the snowbirds know or they’ll all wake up dead tomorrow
Adaptation to global heating, results in the average person having to face the weather of whatever city is located 300 Km South of their present location…north in the southern hemisphere. You probably won’t even have to throw out a sweater ! But adapting your budget to the new carbon taxes might be demanding….
What carbon? The rate this is going, there won”t be any.
What a wonderful abstract, er…..abstraction! –
Is it 1st April already?
Sure looks like it Phillip, but the paper is so obviously planned to yield the result expected it is a totally effort.
Computer programs only produce what is programmed into them. They openly admitted that the program was designed to produce the result.
Bogus!
Climate models have only one date.
Here are falsifiable predictions for the coming decade. Universe is going to collapse in 2025, followed by Ice age in 2026, catastrophic global warming in 2027 and by the end of 2028 whole of the England’s Covid-19 infections will be tracked and trace and princess Nut-Nuts will be elected as the PM of England & Wales. .
Suggested addition to WUWT: A Doomsday calendar keeping track of all the events leading to our certain demise….
Is that you David Suzuki?
You scenarios were credible until you said track and trace will be fixed in just eight years. I can no longer take you seriously.
‘The linearity of the forced response’.
That explains it, they believe that nonsense. Never heard of logarithms.
Never heard of coupled non-linear chaotic systems either
When the math gets too hard, its best to ignore it.
when it doubt leave it out! or double it ….
What they say makes it a fact! See how easy that was? Beam me up, Scotty.
The T^4 relationship to W/m^2 dictated by the Stefan-Boltzmann LAW doesn’t seem to matter either.
The bogus claim of approximate linearity between T and W/m^2 around the mean climate response has its poisonous tentacles reaching everywhere. This assumption is the preeminent failure of IPCC climate science that by ignoring the requirements of physics, both exaggerates warming trends as it minimizes cooling trends. Without this assumption, the meme collapses.
Their models are far more in error than the difference between T^4 and linear over the range in question. You let them off lightly if you think it’s that.
They are rigged ( “tuned” ) from the word go. Simply dozens of poorly constrained parameters are tuned and tweaked to get a result they want to see. If it looks right, it is right, so they just end up modelling their expectations and/or agenda, not the climate.
Yes, there are many more errors than false linearity, but many of these can be traced back to this primordial assumption. One reason is that when you ignore T^4, you need to add all sorts of heuristic fudge factors, each of which offers an opportunity to push results in a desired direction.
The only demonstrable linearity in the system is between W/m^2 and other W/m^2 which of course, is a prerequisite of COE. It’s almost like alarmists fail to understant that 1 Watt is 1 Joule per second and that COE applies to Joules.
Yes, the Swamp extends to the universities, too!
Our new approach to projecting the Earth’s temperature is based on historical climate data, rather than the theoretical relationships that are imperfectly captured by the GCMs.”
Excuse you, but historical climate data shows the Earth’s temperature to be much warmer throughout most of the Holocene than it is today.
If they used actual “historical climate data”, the type that is written down, and is unmodified by computer manipulation, then they would see there is no need to fear CO2 because it was just as warm in the Early Twentieth Century as it is today, even though CO2 concentrations have increased steadily since the Early Twentieth Century. More CO2 in the atmosphere, yet it is no warmer now than when there was much less CO2 in the atmosphere. Therefore, CO2 has little effect on the Earth’s temperature.
See how simple that was. I just used historical climate data (regional surface temperature charts) to reach those conclusions. It doesn’t need any computer manipulation. Just the actual data will suffice. It was just as warm in the recent past as it is today, yet there is more CO2 in the atmosphere now, than then, which means CO2 has no measureable effect on the Earth’s atmosphere or weather.
The reason the Climate Alarmists don’t use the actual data is because it blows up their catastrophic CO2 narrative.
And when these guys say they are using the historical climate data, I imagine they are referring to the bastardized, modern-era Hockey Stick charts,
Here’s a hint in case you didn’t know, but the Hockey Stick charts are really science fiction, and bare no resemblance to reality. If you are basing your work on this being accurate then you are wasting your, and our time.
You can’t look at historical temperture data and believe in Human-caused Climate Change. The historical temperature data refutes the Human-caused Climate Change meme.
Many upvotes.
One doesn’t even have to go back very far in time. Between 1940 and 1980 there was a substantial global cooling, at a time when CO2 emissions were growing rapidly. This alone falsifies the central hypothesis of the Warmunists.
“Source: McGill University
The threshold for dangerous global warming will likely be…”
From my file of quoted, factoids and smart remarks:
Somewhere in an environmental science department at some cruddy university not far from you, a bunch of otherwise unemployable climate science graduates are working on yet another paper demonstrating that global warming is a really serious problem which can only be solved if millions of dollars in funding grants are chucked at it. James Delingpole
James should know better–most “climate scientists” are in the geography departments.
https://tambonthongchai.com/2020/12/23/1-5c-by-2027-2/
“….stochasticity of the internal variability, and the linearity of the forced response….”
But of course.
They also invented the Heisenberg Compensator.
Beam me up Scotty!!
All that obfuscating babble is to simply say, “We pulled out some graph paper and a ruler, and using y=mx+b, we drew some lines out starting from 1910 to 2100. The slope, m, of the lines were pulled from CMIP5 RCP’s, which themselves were made-up gibberish.”
Further they assume the arbitrary 1.5ºC level means something since everyone keeps using it. But no one knows why it’s 1.5ºC, and not 1.6ºC, or 2.5ºC, or 1.4ºC. The 1.5ºC is just an arbitrary number that has morphed into a superstition-like cultural belief that something bad happens at that point. This is Cargo-Cult Science writ large, in Trillion dollar figures.
goodness gracious, that was some TreknoBabble, I could visualize the author wearing an old-style carburetor air filter around his forehead whilst writing that
Could I suggest the arbitrary 1.5ºC was spun at Paris when they realised we would probably come in under 2ºC on business-as-usual – a danger to the plans of the green profiteers.
30 years ago, 3ºC was the danger point. Then 20 years ago it morphed to a 2ºC danger point because 3º was too far off for the Pols paying the climate scam bills for no return.
Then starting around 10 years ago, well into the Hiatus (pause, etc), the Danger Point became 1.5ºC out of political necessity so the Pols could proclaim the Danger, and thus Crisis, was imminent.
…as long as the Great Reset Initiative accepts it, they’re good to go. What their critics say matters little to nothing.
We will find any means necessary to continue the crisis! We will not be stopped. We will control the world. The plan for WORLD Domination of the western world continues CCP will love us.
Don’t knock it Rich it’s working.
Biden is being urged to declare a “climate emergency” which appears to mean de-industrialize the USA and let China take over all manufacturing for the no-longer-free world.
All these weak papers will be quoted as hundreds of dire predictions from climate ‘scientists’.
Well now, they have a “new approach” that will give us all the answers this time! What could possibly go wrong?
/sarc
Begs the question ‘why is there a need for a new approach if the science is settled’?
Oh hold on, I think I can guess…..
Historical???
I stopped reading at the blah, blah, blah.
I’ve long-since given up on these ‘studies’. They’re done to bolster claims of ‘catastrophe’ and keep the funding flowing.
No catastrophe = no funding and an end to the fake ‘crisis’. And we can’t have that.
“equilibrium climate sensitivity as: 1.7+0.3−0.21.7−0.2+0.3 K and 2.4+1.3−0.62.4−0.6+1.3 K respectively (likely range).”
How is a number with two decimal points interpreted? My computer says it’s an error. Who am I to argue? This was not covered in the classes I took to get a BS in math. Anyway, I ignore anyone who claims to be able to ‘more accurately predict the future.
…they will claim that your BS isn’t what you think it is.
No no, it’s been peer reviewed. The problem is with you, not the equation. Be careful, they’re opening a Chinese style reeducation camp near you soon.
Can we have it now? Snowing and blowing a hooly here.
Does someone have cancer? They usually put their silly doomsday calls outside of their own lifetime or at least professional life.
If this is the quality of their work it probably will be outside their professional life.
The problem is the total UNACCOUNTABLY of any of the climate nonce’s making these predictions.
There are no career consequences of being totally and completely wrong..
.. in fact, it seems that being totally and absolutely wrong in “Climate Science” is more a feather in the cap.
Just making the prediction, get you your next career points, even when it never occurs.
…the seriousness of the charge is way more important than anything else.
They know that, by the time their idiotic predictions have been falsified, they will have reaped the benefits in terms of professional advancement, grants and pensions.
Just curious, but how is this “prediction” different from prior predictions?
Good old Bayes. The prior probability of climate disaster predictions is extremely low and thus would take extraordinary proof.
Amazing that they stil are using RCP 8.5, and considering that ECS has a relaxation time of at least four centuries for 2xco2. Equilibrium sensitivity is completely meaningless for policimakers nkw and in the the coming decades.
TCR and ECS timescales
https://archive.ipcc.ch/ipccreports/tar/wg1/fig9-1.htm
Bottom line: a transient climate response of 1.7+0.3−0.2 is not dangerous.
RCP 8.5 was developed as an unlikely, far-out upper bound for human behavior. The report that contained it specifically said it was unrealistic and not intended as an actual possible state.
So get rid of it in research. The world is not going to continue for a century burning more and more oil and coal without limit, everywhereon earth.
Hmmmm, they state that their method removes previous massive uncertainties?
There was massive uncertainty?
I thought the whole point was that there wasn’t massive uncertainty?
This is just another “model” with all the inherent “climate scienceᴸᴼᴸ” fudge factors.
It is one model, and has a range less than the whole Chimp5 ensemble
Whoopy-doo !!
So full of erroneous, unscientific assumptions, as to be just as worthless as the models from 5 or 6 chimps.
Sounds like they’re running short on Gov. funding so we need more scary climate stories, “OH NO its worse than we thought ” Santa has come and gone,
now it’s time for Chicken Little…..
“Climate skeptics have argued that global warming projections are unreliable because they depend on faulty supercomputer models. While these criticisms are unwarranted”
Any thinking person knows that criticism of climate models is warranted owing to the extremely large range of predictions. Add to that the fact that 95% of the models have overpredicted temperatures during the last decade and you know that these climate models are not useful. Period. Anyone who claims that criticism is not valid simply cannot be trusted.
What on earth was that before it went through copy and paste ?
…probably not much difference.
A space was clobbered in the middle of 21 and 62?
OMG, more damned potty Potsdammers .
Neither 1.5 or 2.0 is defined as “dangerous”. These arbitrary political targets where supposed to be limits below which we could be fairly confident warming was safe.
This is not a black/white safe/”dangerous” choice which flips at 2.01 deg C.
It is a deliberate misrepresentation to redefine 2.0 as the beginning of “dangerous” warming. That is not what the IPCC says.
We have global warming every year. It’s called ‘summer’. These ‘scientists must have missed it.
Well, semi-global warming at least every year.
(pedants rule, ok)
Obviously these stories of summer are a myth, since it doesn’t happen all over the planet simultaneously.
Yeah, it’s just a local thingy.