Very nice analysis of the various factors contributing to warming. And extra credit for pointing out the Y-axis change in the 2015-2024 chart! This work would definitively abolish silly arguments like “it’s just natural variations” … if only those who do argue would read and absorb this information.
Thank you! An interesting topic for a future piece of writing would be negative feedbacks (e.g. due to increased chemical weathering) and their impact on the rate of warming. There is much of popular writings on positive feedbacks, but not that much on negative feedbacks.
Changes in chemical weathering (I assume you mean carbonate and silicate weathering?) should be pretty negligible over the time periods we are talking about here. Though there are some pretty big negative feedbacks (Planck, land carbon response to CO2) that are relevant.
Great analysis and very timely. Does it agree with the Hansen et al. paper "Warming in the pipeline..."? They propose a decadal warming rate between .27 C and .36 C starting in 2020.
It would tend to indicate a decadal warming rate higher than historical but on the low end of Hansen's projections. That being said, I'm just showing the central (p50) estimates, and using higher-end estimates associated with higher climate sensitivity and aerosol forcings would be in-line with Hansen's range.
In the recent Goessling &al paper reduced cloud cover was identified as one important component of recent warmin acceleration. Now this has, according to him, several causal factors: less condensation nuclei (partly bc of less sulfur dioxide), drier air bc of mere temperature increase itself, and possible decadal oscillations in the climate system.
The cloud cover changes identified by Goessling and other recent work is quite important, but it represents a feedback to the forcings shown here rather than a forcing in-and-of itself. E.g. cloud cover is changing either due to aerosol declines or due to a response to increasing atmospheric greenhouse gas concentrations (assuming its not natural variability at play!). This would show up in the lamda assumed by the model (e.g. the conversion of radiative forcing from a particular factor into temperature response), which is where all the various feedbacks live. This parameterized version of FaIR uses a lamda uncertainty range tuned to that identified in the AR6, though the results of Goessling et al could suggest a value in the higher end of that range is more appropriate. Its just a bit premature to know at this point!
A f a i u, sorry if I just repeat what you wrote: if cloud cover responds to the mere temperature increase, it is implicitly responding to all listed factors at once. This feedback mechanism would then work as an increasing factor, like
Thats what solar radiation management is I think. It takes particles from volcanoes and spreads them about in the atmosphere. The sun is then reflected away from the Earth. Only trouble is you have to every nation to agree and there may be issues with respiratory diseases; the lack of vitamin D; the blocking photosynthesis in the plants we're all 100% dependent upon; adverse psychological disorders from white skies and the thwarting of solar panels.
To add to that, tropospheric aerosol emissions today are responsible for millions of deaths per year due to outdoor air pollution, so they are definitely worth cleaning up regardless of their climate effects.
Is there any significant forcing from the growth of urban heat islands and the heat, not GHGs, generated by human activities, manufacturing, machinery, etc, that yearly increases and won't plateau anytime soon?
Michael, since no expert has responded to your question, I'll give it a shot. I did a search for "waste heat"+"climate change" on Google Scholar. The top hit was a 2020 paper titled "Waste heat: the dominating root cause of current global warming" (environmentalsystemsresearch.springeropen.com/articles/10.1186/s40068-020-00169-2). The abstract rebunks long-debunked denialist memes:
"Pursuing GHG reductions by means of all resources and efforts has turned out no result to stop or even slow the global warming: the globe still gets warmer and warmer, especially in the recent years, at record-breaking rate almost each single year. Additionally, no definitive relationship has been found between the warming and the atmospheric GHG concentration. The link between them even in IPCC’s report lacks support and is unconvincing. All these imply that something else is responsible for the warming."
Snort! Extraordinary claims require extraordinary evidence: at best, this evidence isn't. Who the heck reviewed this stuff? It's motivated bullshit masquerading as science. This is where scientific meta-literacy is useful (J. Nielsen-Gammon's Houston Chronicle blog post is only available on the Wayback Machine: web.archive.org/web/20130213192911/https://blog.chron.com/climateabyss/2013/02/scientific-meta-literacy). I'd be skeptical (as originally defined) of anything published in that journal. Further investigation might follow the money.
"Radiative forcing of waste heat is quickly surpassed by that of associated CO2."
If you'll accept a quasi-peer-reviewed source, SkepticalScience.com graphically shows the relatively small contribution of waste heat from burning fossil fuels to global radiative forcing:
"To conclude, greenhouse warming is currently adding some 60-100 times more heat to our climate than waste heat. That's not to say we should not be bothered about waste heat though, There are many sound reasons, including economic, for reducing heat wastage. It makes no sense at all to tolerate systems that for various reasons are grossly inefficient. But that needs to be considered as a separate entity from the huge problem of human CO2 emissions."
As always, I'm a comprehensive non-expert, but I take that quantitative comparison as definitive.
You can work out pretty easily that waste heat is not a big contributor to global climate change. In a city, it might be warming local regions by a bit.
The fact that people are seriously looking into it fills me with dread!
I look at any intervention into such a complex, self-regulating system as the epitome of hubris. A bit like statins, that block the bodies ability to make it's own cholesterol, and can lead to dementia, loss of libido, neuropathy and muscle pain. And only improve atherosclerosis and death by 0.3% over 4 years anyway(and these studies weren't placebo controlled and may have confounders such as changes in lifestyle).
Yet people spend $billions on them because they think they can carry on eating saturated fat. It's a joke.
I absolutely know that we don't know enough not to balls up intentional geoengineering 🙏🏽
Jo, all the peer-reviewed evidence I can find shows that statins have significantly reduced mortality from cardiovascular disease (e.g. pubmed.ncbi.nlm.nih.gov/36233511/). Do you think those findings are false? What peer-reviewed evidence of lower efficacy do you have?
The risks of specific side effects are known, and IMHO they're outweighed by the documented benefits. FWIW, when my cholesterol numbers were too high 20 years ago, I was prescribed a statin, and my numbers have been back in the normal range ever since. I've suffered no untoward side effects, and I enjoy a modest amount of saturated fat in my diet. My PCP says my CV health is fine. I regard statins as a triumph of modern medicine.
At age 71 I look at any intervention in my health as a gamble, which can pay off in longer life and better QOL, and if not only I am affected. And I don't expect to live forever, even with the best medicine! I'm willing to gamble with statins, but not with trying to cool the earth by injecting SO2 into the stratosphere, because that's gambling with the whole world, without good evidence of efficacy or safety. WRT to global warming, my hopes are all on decarbonizing the global economy ASAP, and adapting to the highest GMST reached by the time that's accomplished. Does that seem like hubris to you?
Surprisingly, statins are more relevant to climate science than one might suspect.
The controversy over their effectiveness boils down to this:
One recent meta-analysis explained that decisions to hospitalize patients and perform bypass surgeries are at the discretion of doctors. Since these are subjective decisions, the study applies the term 'relative risk' in order to isolate and control for the subjective nature of these interventions when evaluating 'absolute risk'.
The meta-analysis concluded that statins provide essentially no benefit after controlling for subjective interventions of hospitalization and bypass. It reached this conclusion by focusing on objective outcomes from thrombotic embolism alone (death, heart attack, stroke). It did not isolate specific confounding effects of subjective treatment decisions, but it did control for them.
Examples of potential confounding effects:
Bypass surgery could make statins appear to be more effective than they actually are, depending on whether or not bypass surgery has long-term benefit, and depending on whether or not bypass surgery is attributed as an adverse event.
The preference to provide subjective bypass treatments may by stronger for patients who are already taking statins. If bypass provides long-term benefit, conflating the *benefit* of bypass with the benefit of statins could inflate the relative benefit of statins.
Alternatively, the preference to provide subjective bypass treatments may be stronger for patients who are not taking statins. If bypass provides no long-term benefit, conflating the *adverse event* of bypass surgery with the adverse event of thrombotic embolism could also inflate the relative benefit of taking statins.
My prior investigation of older research reveals that bypass provides no long-term benefit because advanced atherosclerotic damage quickly clogs the grafts. John McDougall referenced such studies in his pioneering 1980s book McDougall's Medicine.
If bypass only provides long-term benefit when the patient is also taking statins to prevent the graft from becoming blocked, then the recent meta-analysis may detect the simultaneous combined therapy of both statins and grafts driving favorable outcomes rather than statins alone.
Unclogging and stenting are other subjective uncertainties that might obscure the benefits of statins. Similarly, the benefits of lowered LDL levels with statins may be illusory if similarly conflated with other risk reductions such as dietary intervention and exercise.
This recent meta-analysis illustrates that it is impossible to attribute the 'relative' risk reduction benefit of statins objectively. The only way to attribute benefits of statins robustly is to control for subjective factors by ignoring them in the meta-analysis and focusing solely on the single objective outcome of thrombotic embolism that mainly manifests as death, heart attack, or stroke.
Since the nuance is too confusing to attribute in layman's terms, the popular press ignored the definitions of relative vs. absolute risk reduction, obscuring the science and causing confusion about why the distinction is important. Here's one example where the definitions are absent from the press coverage even though the percentages are included:
The original study included the definitions of relative vs absolute risk, but these distinct risks are not clearly differentiated from each other in layman-friendly language with examples the way I just did. I had to heavily interpret the study to explain it in the terms that I understand it, as a layman, after reading very carefully and synthesizing with my pre-existing layman's knowledge:
It's no surprise that there is confusion about statins. Pharmaceutical companies aren't financially incentivized to expose the uncertainties of the benefits any more than they are incentivized to expose the uncertainties of the risks when designing and publishing their clinical trials. There is inherent conflict of interest.
Many medications are taken off the market by regulators years after introduction when independent retrospective studies reveal problems.
This conflict of interest is also why mavericks like John McDougall languish in obscurity and are mercilessly gaslit in their Wikipedia bios after correctly identifying the root cause of things like heart disease: half of everyone has a gene that prevents us from adequately metabolizing LDL. The best remedy is to eliminate animal products from our diets, because nothing else effectively keeps the vulnerable half of the population healthy.
We don't know exactly why this split in genetic diversity occurred, but I suspect that maybe with the advent of agriculture, we are less vulnerable to famine. The reduced need to pack on calories during the growing season may have allowed humans with lower cholesterol tolerance to survive and expand diversity in the gene pool. Another potential factor is that carnivores universally metabolize LDL cholesterol well, but omnivores and vegetarians have a harder time of it.
You won't be hearing this take on cholesterol from climate scientists any time soon, but LDL toxicity is yet one more wonderful reason to implement socialistic incentives away from agribusiness feedlot operations, in addition to their outrageous levels of greenhouse gas emissions.
Meanwhile, just as climate scientists are gaslit by denialist propaganda, so too is John McDougall gaslit with implications in his own Wikipedia bio that he is an emaciated, perpetually hungry, bean-chuffing fart machine and cancer conspiracy theorist who promotes folk remedies with no more credibility than laetrile, despite his own approach to life (and the clinic he founded) being based in the current standard of care for both heart disease and cancer.
He survived a stroke in his early twenties before normalizing his own cholesterol exclusively through dietary intervention informed by his own research of what was already established scientific fact as early as 1960. I took his challenge to confirm his claims that the research was 20 years ahead of the standard of care at the time, and checked my own George Mason University library in 1989. I discovered a hardcover volume simply entitled 'Cholesterol' that was published in 1960. It contained all of the facts that the current standard of care emphasizes, including that half of everyone is exceptionally vulnerable to the toxic effect of feedlot animals, and that two eggs per week is sufficient cholesterol intake to saturate the nonlinear response of LDL levels in the half of the human population with the vulnerable gene.
Another aspect is the concentrated usage of omega-6-rich grains in feedlots as opposed to the omega-3-rich grasses of 'grass fed beef' which usually isn't exclusively raised on grasses anyway because that's too slow and expensive. Besides, there is no such thing as grass-fed pork, poultry, or fish. Only ruminants qualify.
Most people don't realize that the less fat a given meat contains, the more cholesterol it contains as a relative fraction of total calories. Shellfish is the worst because of its low fat content.
Meanwhile, Atkins' Wikipedia bio doesn't even mention the speculation that his own family refused an autopsy to prevent the discovery of a blood clot bringing him down with a sudden massive stroke rather than him dying from a slip and fall. He was known to be in poor health. His meat-centric diet is so toxic that most people can't comply with it in the long term even if they try. If an autopsy revealed that his own fad diet killed him, that would be bad for future book sales based on his popular legacy that the family depends upon for their standard of living.
The science robustly supports McDougall over Atkins, but you'd never know it from reading their Wikipedia bios. They are presented at similar levels, as if that's remotely scientific. Their physical appearances in photographs clearly illustrate the remarkable difference in their relative health. McDougall often used photographs of supposed health researchers to illustrate the irony of their claims.
It's interesting that even statins relate to global warming in such an intricate and profound manner. Similar relationships exist for most of modern fossil living. The polycrisis is a remarkable phenomenon.
Thank you for engaging. While modern global civilization abounds in irony ("Faustian bargain" seems apt), health care is particularly fraught, with subjective factors dominant in every personal or professional judgement. Suspicion of "Big Pharma", i.e. for-profit pharmaceutical manufacturers, is assuredly warranted. Your argument would be stronger if you linked the meta-review you cited in opposition, however. Otherwise, the relative death-rate reductions analyzed in the meta-review I cited pretty much speak for themselves, AFAICT.
TBH, I lack sufficient biomedical "meta-literacy" (h/t TX State Climatologist John Nielsen-Gammon) to decisively resolve any peer-reviewed controversy over statins myself. The better part of humility, IMHO, is to assume the experts, who recognize each other by their peer-reviewed output, know more than I do. That's how I approach climate science: I assume the peer-review process, broadly defined, weeds out the most egregious bias. I realize biomedicine encompasses obvious cognitive motivators, but without mutual, trained peer discipline, even experts have no way to know whether they're fooling themselves or not. What are genuinely skeptical lay people to do? Simply the best we can, ever mindful we could be fooling ourselves!
We fool ourselves about our health with lamentable ease (nytimes.com/2024/04/24/opinion/medical-skepticism-doctors-trust.html). Yet anecdotally, I'm provisionally confident my own risk of cardiovascular disease related to high blood cholesterol is less than it would be without daily, generic rosuvastatin (gotta love Medicare). At best, that means something else will kill me first! Neither immortality nor perfect health are attainable, at any price. For me, it's a matter of cost-effective risk management until age catches up with me.
Meanwhile, "the future's uncertain and the end is always near" (J. Morrison). Irony abounds: having taken my rosuvastatin pill this morning, I'll confidently eat a large ribeye steak tonight, with a nice Oregon pinot noir. Do you propose I satisfy myself with wistful imagining instead?
Very useful analysis Zeke. However, not much description of the model and especially feedbacks. No mention of water vapor and its vital role, for instance.
He's using the FAIR model, which is a 2-layer global average model with specified climate sensitivity. They've calibrated the parameters of the model to reproduce the global average behavior of the CMIP models.
I didn't want to spend too much time on the details of the model, but this paper goes into quite a bit of detail on the calibration to ensure it matches the CMIP6/AR6 ranges across various parameters: https://gmd.copernicus.org/articles/17/8569/2024/
I wouldn't give notrickzone.com much belief, myself. Hell, I can't even be bothered to click on your link. I've heard it all before, and it's all still misleading or just plain false.
My own simplistic model relies upon a single recent span in time (August 2023-July 2024, averaging +1.64C over the year) for calibration of normalized SST as a proxy for global surface temperatures above pre-industrial.
I'm also using a linear regression model of SST from localized oscillation modes to subtract out the effects of various local ocean oscillation modes from normalized global SST. I'm using exclusively SST data that isn't perturbed by volcanic eruptions to avoid modeling the eruptions with localized oscillation modes.
I'm doing this linear regression to obtain a low-noise warming trend line without needing sophisticated modeling that is beyond my capability to implement or understand. This is a novel approach and not in line with climate science in general.
I'm getting a trend line that has us crossing 1.5C in July of 2025. This isn't anywhere near IPCC-based model, despite my trend being calibrated to IPCC baseline. I'm wondering why there would be such a marked discrepancy aside from human error and inappropriate methodology on my part with my simplistic method. I've often heard that IPCC estimates of global warming acceleration are overly conservative, and I'm wondering if my primitive approach has identified some sort of bias outside of my own, or if I simply blew it with my inexpert assumptions and calibration.
I'm also seeing us having permanently crossed 1.5C in practical terms in early March of 2023, owing to the currently unexplained pulsed ~0.2C rise of sea surface temperatures.
My model shows that pulse is exponentially decaying, but combined with the overall global warming trend, it manifests as a pause in global warming that I anticipate lasting for 5-9 years. The difference in my extrapolations depends on whether I include the Atlantic Multidecadal Oscillation that some scientists believe isn't an oscillation at all, and that exhibits zero phase delay from SST temperatures. I'm suspecting that it's difficult or impossible to isolate AMO from AMOC, and that the Atlantic exhibits no substantial oscillations in sea surface temperature aside from the wide swings of apparent ringing that we saw during that unexplained pulse in 2023, so I'm trusting my model without AMO better than the one with.
I'd be interested in your interpretation of this result that I'm showing. I've posited on Gavin's RealClimate that maybe there's been some change in teleconnection between the surface ocean and the subterranean ocean that we've been hearing about lately. The pulsed warming has a much sharper attack than the cooling trend from Pinatubo, and also seems to have occurred simultaneously across all ocean depths. Another potential explanation is the collapse of the carbon sink in 2023-2024 and the biological implications upon ocean temperatures of that recent change.
Are there any answers yet? Can you incorporate a model of this pulsed warming in your analysis? The IPCC hasn't yet announced any consensus as to why this pulsed warming occurred.
To the best of my knowledge, IPCC hasn't even acknowledged that it is a pulse either, so my own result seems to be an original contribution to the science, even if the calibration may be off and the modeling may have systematic error. I'd like an informed opinion as to whether I've made a bona fide discovery of a warming pulse in my quest to understand the gobsmackingly bananas SST warming and Antarctic ice loss of 2023? If I have, those promoting recent acceleration from aerosols may find their claims confounded by the pause in warming that I'm attributing to the currently unexplained portion of recent abrupt warming that seems to have been a one-time occurrence rather than part of a long-term trend.
Details at the link below. I haven't yet posted a comparison between models that includes the one without AMO. I suspect that the inclusion of AMO in my model exaggerates the duration of the pulse because 9 years seems like a really long pause in an accelerating warming trend, but 5 years is a lot more believable. I'll be uploading another version without AMO and pinning it to my profile soon.
Since this pause is detected by subtracting the global effects of localized oscillation modes, it isn't directly observable in uncompensated normalized SST. Also, since the model is largely uncalibrated and may have systematic error, the decaying pulse may be an artifact of the model rather than real...but it sure looks real on a visually graphical level after detrending the compensated SST data. Visually compelling results like this seem to me authentic, especially given that I've also credibly detected the appropriate magnitude and duration of cooling from Pinatubo that I wasn't even looking for when I first began this investigation, as well as Chichon and associated eruptions pre-dating Pinatubo, plus maybe an earlier Hunga Tonga submarine eruption pre-dating the most recent one in 2022.
Thanks in advance for any insights you may apply to my result, or any elaboration you can supply on the 'missing factor' that your own analysis may not have taken into account, since there's no consensus yet on what caused the unexplained +0.2 degrees C of abrupt warming in 2023 that seems to have persisted past the end of the ENSO maximum but apparently hasn't caused any acceleration on its own:
Great article Zeke! i tried to find any peer-reviewed articles that attempt a similar breakdown and came up empty. surely researchers have done this decomposition previously in other models? was hoping to be able to reference similar results from a more comprehensive ESM to back up these numbers... thanks!
Does there exist an attribution, like in the first chart, for the northern hemisphere? Given that aerosols predominantly affect the NH, we should have had a negative total forcing for most of the time there, only turning positive lately.
The rate of warming is the derivative of total warming, so the timing when aerosols switch from reducing to increasing the rate of warming depends on when aerosol emissions peak and start to decline rather than their magnitude.
The correlation of the two piece linear fit with adjusted temperatures is striking. Of course just a statistical fit and the temperatures are adjusted.
For those interested in sulfate modifications of the atmosphere remember that volcanos decrease both temperature and precipitation. If your farmers get drought would you be very happy?
Is “solar output” just referring to very long term variation in solar luminosity? Or is it also taking into account variation in Earth’s orbit (Milankoch cycles driving recent ice ages)? Because the climate denier argument is to say “we’re still leaving the last ice age” so to refute that the expected temperature change as a function of Milankovich cycles must be included
Milankovich cycles have not changed over the past 150 years, they vary over tens to hundreds of millennia, so putting ~0.0001 w/m^2 into a model will give you no change (and, more broadly, represent a quite small external radiative forcing and rely extensively on feedbacks for amplification – including CO2! https://www.carbonbrief.org/explainer-how-the-rise-and-fall-of-co2-levels-influenced-the-ice-ages/)
Well sure Milankoch cycles haven’t “changed” much but the normal cycling I was referring to has big impacts on climate on the 20,000 to 100,000 time scales and are thus relevant to discussions about exiting the last ice age ~10,000 years ago, i.e., would the shorter precession and obliquity cycles, superimposed, result in warming or cooling now, absent changes in CO2? It wasn’t clear to me that the normal cycling of precession and obliquity were taken into account here, but maybe it was. This NASA link suggests our current position in the super imposed Milkanvich cycles would result in cooling, maybe that’s lumped into your “solar output” portions
EDIT: I see your link discusses how the cycles are not really independent sources of warming/cooling, so I assume it would be difficult (meaningless?) to tease apart the orbital cyclicity while holding CO2 constant.. better I guess to see total aggregate cooling/heating net effect predicted today absent anthropogenic CO2…
A question: James Hansen has written several times in his blog in recent years that aerosols are still not being measured and that their contribution to warming is therefore unclear. He called for the amount and effect of aerosols to finally be measured.
In this article, the first diagram shows a very large error range for aerosols, which fits with Hansen's statement, but the other diagrams show exact numbers and curves without this wide error range.
So here's the question: contrary to Hansen's statement, are there precise measurement data on aerosols and their effect on temperatures from 1905 to today as shown in the two diagrams below?
The earth isn’t going to boil, only the inept UN and its arrogant child, the IPCC, peddle that nonsense because their continued taxpayer funding depends upon it!
Does this mean when we see assumed temperature targets in the future like 2- 2.5 degrees we should add .5 degrees to it? Does this mean we're currently at 1.8C? Or is there something that balances this out as we reduce emissions?
Very nice analysis of the various factors contributing to warming. And extra credit for pointing out the Y-axis change in the 2015-2024 chart! This work would definitively abolish silly arguments like “it’s just natural variations” … if only those who do argue would read and absorb this information.
Nothing to add. Nice concise summary. Nice job.
Thank you! An interesting topic for a future piece of writing would be negative feedbacks (e.g. due to increased chemical weathering) and their impact on the rate of warming. There is much of popular writings on positive feedbacks, but not that much on negative feedbacks.
All the best to you and you family for 2025!
Changes in chemical weathering (I assume you mean carbonate and silicate weathering?) should be pretty negligible over the time periods we are talking about here. Though there are some pretty big negative feedbacks (Planck, land carbon response to CO2) that are relevant.
Great analysis and very timely. Does it agree with the Hansen et al. paper "Warming in the pipeline..."? They propose a decadal warming rate between .27 C and .36 C starting in 2020.
It would tend to indicate a decadal warming rate higher than historical but on the low end of Hansen's projections. That being said, I'm just showing the central (p50) estimates, and using higher-end estimates associated with higher climate sensitivity and aerosol forcings would be in-line with Hansen's range.
Thx.
In the recent Goessling &al paper reduced cloud cover was identified as one important component of recent warmin acceleration. Now this has, according to him, several causal factors: less condensation nuclei (partly bc of less sulfur dioxide), drier air bc of mere temperature increase itself, and possible decadal oscillations in the climate system.
How would you place this in your diagram?
https://www.science.org/doi/10.1126/science.adq7280
The cloud cover changes identified by Goessling and other recent work is quite important, but it represents a feedback to the forcings shown here rather than a forcing in-and-of itself. E.g. cloud cover is changing either due to aerosol declines or due to a response to increasing atmospheric greenhouse gas concentrations (assuming its not natural variability at play!). This would show up in the lamda assumed by the model (e.g. the conversion of radiative forcing from a particular factor into temperature response), which is where all the various feedbacks live. This parameterized version of FaIR uses a lamda uncertainty range tuned to that identified in the AR6, though the results of Goessling et al could suggest a value in the higher end of that range is more appropriate. Its just a bit premature to know at this point!
A f a i u, sorry if I just repeat what you wrote: if cloud cover responds to the mere temperature increase, it is implicitly responding to all listed factors at once. This feedback mechanism would then work as an increasing factor, like
real_temp_increase = temp_increase_after_all_factors * temp_cloud_feedback_factor
Maybe a stupid question, but: If aerosols cool the climate, can we use them to fight climate change?
And how does cooling work?
Thats what solar radiation management is I think. It takes particles from volcanoes and spreads them about in the atmosphere. The sun is then reflected away from the Earth. Only trouble is you have to every nation to agree and there may be issues with respiratory diseases; the lack of vitamin D; the blocking photosynthesis in the plants we're all 100% dependent upon; adverse psychological disorders from white skies and the thwarting of solar panels.
https://jowaller.substack.com/p/im-anti-vax-and-anti-geoengineering?utm_source=publication-search
To add to that, tropospheric aerosol emissions today are responsible for millions of deaths per year due to outdoor air pollution, so they are definitely worth cleaning up regardless of their climate effects.
Whether we'd want to purposefully do stratospheric sulfur aerosol geoengineering is a separate debate: https://www.theclimatebrink.com/p/the-geoengineering-question
Is there any significant forcing from the growth of urban heat islands and the heat, not GHGs, generated by human activities, manufacturing, machinery, etc, that yearly increases and won't plateau anytime soon?
Michael, since no expert has responded to your question, I'll give it a shot. I did a search for "waste heat"+"climate change" on Google Scholar. The top hit was a 2020 paper titled "Waste heat: the dominating root cause of current global warming" (environmentalsystemsresearch.springeropen.com/articles/10.1186/s40068-020-00169-2). The abstract rebunks long-debunked denialist memes:
"Pursuing GHG reductions by means of all resources and efforts has turned out no result to stop or even slow the global warming: the globe still gets warmer and warmer, especially in the recent years, at record-breaking rate almost each single year. Additionally, no definitive relationship has been found between the warming and the atmospheric GHG concentration. The link between them even in IPCC’s report lacks support and is unconvincing. All these imply that something else is responsible for the warming."
Snort! Extraordinary claims require extraordinary evidence: at best, this evidence isn't. Who the heck reviewed this stuff? It's motivated bullshit masquerading as science. This is where scientific meta-literacy is useful (J. Nielsen-Gammon's Houston Chronicle blog post is only available on the Wayback Machine: web.archive.org/web/20130213192911/https://blog.chron.com/climateabyss/2013/02/scientific-meta-literacy). I'd be skeptical (as originally defined) of anything published in that journal. Further investigation might follow the money.
The second hit on Google Scholar was "Quantification of global waste heat and its environmental effects"(sciencedirect.com/science/article/abs/pii/S0306261918316702). It draws the reality-based conclusion:
"Radiative forcing of waste heat is quickly surpassed by that of associated CO2."
If you'll accept a quasi-peer-reviewed source, SkepticalScience.com graphically shows the relatively small contribution of waste heat from burning fossil fuels to global radiative forcing:
"To conclude, greenhouse warming is currently adding some 60-100 times more heat to our climate than waste heat. That's not to say we should not be bothered about waste heat though, There are many sound reasons, including economic, for reducing heat wastage. It makes no sense at all to tolerate systems that for various reasons are grossly inefficient. But that needs to be considered as a separate entity from the huge problem of human CO2 emissions."
As always, I'm a comprehensive non-expert, but I take that quantitative comparison as definitive.
You can work out pretty easily that waste heat is not a big contributor to global climate change. In a city, it might be warming local regions by a bit.
Thanks, Andrew. I was sure we'd all much rather hear from you on this!
Hiya,
The fact that people are seriously looking into it fills me with dread!
I look at any intervention into such a complex, self-regulating system as the epitome of hubris. A bit like statins, that block the bodies ability to make it's own cholesterol, and can lead to dementia, loss of libido, neuropathy and muscle pain. And only improve atherosclerosis and death by 0.3% over 4 years anyway(and these studies weren't placebo controlled and may have confounders such as changes in lifestyle).
Yet people spend $billions on them because they think they can carry on eating saturated fat. It's a joke.
I absolutely know that we don't know enough not to balls up intentional geoengineering 🙏🏽
Jo, all the peer-reviewed evidence I can find shows that statins have significantly reduced mortality from cardiovascular disease (e.g. pubmed.ncbi.nlm.nih.gov/36233511/). Do you think those findings are false? What peer-reviewed evidence of lower efficacy do you have?
The risks of specific side effects are known, and IMHO they're outweighed by the documented benefits. FWIW, when my cholesterol numbers were too high 20 years ago, I was prescribed a statin, and my numbers have been back in the normal range ever since. I've suffered no untoward side effects, and I enjoy a modest amount of saturated fat in my diet. My PCP says my CV health is fine. I regard statins as a triumph of modern medicine.
At age 71 I look at any intervention in my health as a gamble, which can pay off in longer life and better QOL, and if not only I am affected. And I don't expect to live forever, even with the best medicine! I'm willing to gamble with statins, but not with trying to cool the earth by injecting SO2 into the stratosphere, because that's gambling with the whole world, without good evidence of efficacy or safety. WRT to global warming, my hopes are all on decarbonizing the global economy ASAP, and adapting to the highest GMST reached by the time that's accomplished. Does that seem like hubris to you?
Surprisingly, statins are more relevant to climate science than one might suspect.
The controversy over their effectiveness boils down to this:
One recent meta-analysis explained that decisions to hospitalize patients and perform bypass surgeries are at the discretion of doctors. Since these are subjective decisions, the study applies the term 'relative risk' in order to isolate and control for the subjective nature of these interventions when evaluating 'absolute risk'.
The meta-analysis concluded that statins provide essentially no benefit after controlling for subjective interventions of hospitalization and bypass. It reached this conclusion by focusing on objective outcomes from thrombotic embolism alone (death, heart attack, stroke). It did not isolate specific confounding effects of subjective treatment decisions, but it did control for them.
Examples of potential confounding effects:
Bypass surgery could make statins appear to be more effective than they actually are, depending on whether or not bypass surgery has long-term benefit, and depending on whether or not bypass surgery is attributed as an adverse event.
The preference to provide subjective bypass treatments may by stronger for patients who are already taking statins. If bypass provides long-term benefit, conflating the *benefit* of bypass with the benefit of statins could inflate the relative benefit of statins.
Alternatively, the preference to provide subjective bypass treatments may be stronger for patients who are not taking statins. If bypass provides no long-term benefit, conflating the *adverse event* of bypass surgery with the adverse event of thrombotic embolism could also inflate the relative benefit of taking statins.
My prior investigation of older research reveals that bypass provides no long-term benefit because advanced atherosclerotic damage quickly clogs the grafts. John McDougall referenced such studies in his pioneering 1980s book McDougall's Medicine.
If bypass only provides long-term benefit when the patient is also taking statins to prevent the graft from becoming blocked, then the recent meta-analysis may detect the simultaneous combined therapy of both statins and grafts driving favorable outcomes rather than statins alone.
Unclogging and stenting are other subjective uncertainties that might obscure the benefits of statins. Similarly, the benefits of lowered LDL levels with statins may be illusory if similarly conflated with other risk reductions such as dietary intervention and exercise.
This recent meta-analysis illustrates that it is impossible to attribute the 'relative' risk reduction benefit of statins objectively. The only way to attribute benefits of statins robustly is to control for subjective factors by ignoring them in the meta-analysis and focusing solely on the single objective outcome of thrombotic embolism that mainly manifests as death, heart attack, or stroke.
Since the nuance is too confusing to attribute in layman's terms, the popular press ignored the definitions of relative vs. absolute risk reduction, obscuring the science and causing confusion about why the distinction is important. Here's one example where the definitions are absent from the press coverage even though the percentages are included:
https://theconversation.com/benefits-of-statins-may-have-been-overstated-new-study-175557
The original study included the definitions of relative vs absolute risk, but these distinct risks are not clearly differentiated from each other in layman-friendly language with examples the way I just did. I had to heavily interpret the study to explain it in the terms that I understand it, as a layman, after reading very carefully and synthesizing with my pre-existing layman's knowledge:
https://jamanetwork.com/journals/jamainternalmedicine/fullarticle/2790055
It's no surprise that there is confusion about statins. Pharmaceutical companies aren't financially incentivized to expose the uncertainties of the benefits any more than they are incentivized to expose the uncertainties of the risks when designing and publishing their clinical trials. There is inherent conflict of interest.
Many medications are taken off the market by regulators years after introduction when independent retrospective studies reveal problems.
This conflict of interest is also why mavericks like John McDougall languish in obscurity and are mercilessly gaslit in their Wikipedia bios after correctly identifying the root cause of things like heart disease: half of everyone has a gene that prevents us from adequately metabolizing LDL. The best remedy is to eliminate animal products from our diets, because nothing else effectively keeps the vulnerable half of the population healthy.
We don't know exactly why this split in genetic diversity occurred, but I suspect that maybe with the advent of agriculture, we are less vulnerable to famine. The reduced need to pack on calories during the growing season may have allowed humans with lower cholesterol tolerance to survive and expand diversity in the gene pool. Another potential factor is that carnivores universally metabolize LDL cholesterol well, but omnivores and vegetarians have a harder time of it.
You won't be hearing this take on cholesterol from climate scientists any time soon, but LDL toxicity is yet one more wonderful reason to implement socialistic incentives away from agribusiness feedlot operations, in addition to their outrageous levels of greenhouse gas emissions.
Meanwhile, just as climate scientists are gaslit by denialist propaganda, so too is John McDougall gaslit with implications in his own Wikipedia bio that he is an emaciated, perpetually hungry, bean-chuffing fart machine and cancer conspiracy theorist who promotes folk remedies with no more credibility than laetrile, despite his own approach to life (and the clinic he founded) being based in the current standard of care for both heart disease and cancer.
He survived a stroke in his early twenties before normalizing his own cholesterol exclusively through dietary intervention informed by his own research of what was already established scientific fact as early as 1960. I took his challenge to confirm his claims that the research was 20 years ahead of the standard of care at the time, and checked my own George Mason University library in 1989. I discovered a hardcover volume simply entitled 'Cholesterol' that was published in 1960. It contained all of the facts that the current standard of care emphasizes, including that half of everyone is exceptionally vulnerable to the toxic effect of feedlot animals, and that two eggs per week is sufficient cholesterol intake to saturate the nonlinear response of LDL levels in the half of the human population with the vulnerable gene.
Another aspect is the concentrated usage of omega-6-rich grains in feedlots as opposed to the omega-3-rich grasses of 'grass fed beef' which usually isn't exclusively raised on grasses anyway because that's too slow and expensive. Besides, there is no such thing as grass-fed pork, poultry, or fish. Only ruminants qualify.
Most people don't realize that the less fat a given meat contains, the more cholesterol it contains as a relative fraction of total calories. Shellfish is the worst because of its low fat content.
Meanwhile, Atkins' Wikipedia bio doesn't even mention the speculation that his own family refused an autopsy to prevent the discovery of a blood clot bringing him down with a sudden massive stroke rather than him dying from a slip and fall. He was known to be in poor health. His meat-centric diet is so toxic that most people can't comply with it in the long term even if they try. If an autopsy revealed that his own fad diet killed him, that would be bad for future book sales based on his popular legacy that the family depends upon for their standard of living.
The science robustly supports McDougall over Atkins, but you'd never know it from reading their Wikipedia bios. They are presented at similar levels, as if that's remotely scientific. Their physical appearances in photographs clearly illustrate the remarkable difference in their relative health. McDougall often used photographs of supposed health researchers to illustrate the irony of their claims.
It's interesting that even statins relate to global warming in such an intricate and profound manner. Similar relationships exist for most of modern fossil living. The polycrisis is a remarkable phenomenon.
Thank you for engaging. While modern global civilization abounds in irony ("Faustian bargain" seems apt), health care is particularly fraught, with subjective factors dominant in every personal or professional judgement. Suspicion of "Big Pharma", i.e. for-profit pharmaceutical manufacturers, is assuredly warranted. Your argument would be stronger if you linked the meta-review you cited in opposition, however. Otherwise, the relative death-rate reductions analyzed in the meta-review I cited pretty much speak for themselves, AFAICT.
TBH, I lack sufficient biomedical "meta-literacy" (h/t TX State Climatologist John Nielsen-Gammon) to decisively resolve any peer-reviewed controversy over statins myself. The better part of humility, IMHO, is to assume the experts, who recognize each other by their peer-reviewed output, know more than I do. That's how I approach climate science: I assume the peer-review process, broadly defined, weeds out the most egregious bias. I realize biomedicine encompasses obvious cognitive motivators, but without mutual, trained peer discipline, even experts have no way to know whether they're fooling themselves or not. What are genuinely skeptical lay people to do? Simply the best we can, ever mindful we could be fooling ourselves!
We fool ourselves about our health with lamentable ease (nytimes.com/2024/04/24/opinion/medical-skepticism-doctors-trust.html). Yet anecdotally, I'm provisionally confident my own risk of cardiovascular disease related to high blood cholesterol is less than it would be without daily, generic rosuvastatin (gotta love Medicare). At best, that means something else will kill me first! Neither immortality nor perfect health are attainable, at any price. For me, it's a matter of cost-effective risk management until age catches up with me.
Meanwhile, "the future's uncertain and the end is always near" (J. Morrison). Irony abounds: having taken my rosuvastatin pill this morning, I'll confidently eat a large ribeye steak tonight, with a nice Oregon pinot noir. Do you propose I satisfy myself with wistful imagining instead?
Very useful analysis Zeke. However, not much description of the model and especially feedbacks. No mention of water vapor and its vital role, for instance.
He's using the FAIR model, which is a 2-layer global average model with specified climate sensitivity. They've calibrated the parameters of the model to reproduce the global average behavior of the CMIP models.
I didn't want to spend too much time on the details of the model, but this paper goes into quite a bit of detail on the calibration to ensure it matches the CMIP6/AR6 ranges across various parameters: https://gmd.copernicus.org/articles/17/8569/2024/
https://notrickszone.com/2025/01/08/japanese-scientist-the-ipccs-climate-models-are-fundamentally-flawed-use-false-assumptions/
I wouldn’t give the IPCC modellers much belief!
I wouldn't give notrickzone.com much belief, myself. Hell, I can't even be bothered to click on your link. I've heard it all before, and it's all still misleading or just plain false.
My own simplistic model relies upon a single recent span in time (August 2023-July 2024, averaging +1.64C over the year) for calibration of normalized SST as a proxy for global surface temperatures above pre-industrial.
I'm also using a linear regression model of SST from localized oscillation modes to subtract out the effects of various local ocean oscillation modes from normalized global SST. I'm using exclusively SST data that isn't perturbed by volcanic eruptions to avoid modeling the eruptions with localized oscillation modes.
I'm doing this linear regression to obtain a low-noise warming trend line without needing sophisticated modeling that is beyond my capability to implement or understand. This is a novel approach and not in line with climate science in general.
I'm getting a trend line that has us crossing 1.5C in July of 2025. This isn't anywhere near IPCC-based model, despite my trend being calibrated to IPCC baseline. I'm wondering why there would be such a marked discrepancy aside from human error and inappropriate methodology on my part with my simplistic method. I've often heard that IPCC estimates of global warming acceleration are overly conservative, and I'm wondering if my primitive approach has identified some sort of bias outside of my own, or if I simply blew it with my inexpert assumptions and calibration.
I'm also seeing us having permanently crossed 1.5C in practical terms in early March of 2023, owing to the currently unexplained pulsed ~0.2C rise of sea surface temperatures.
My model shows that pulse is exponentially decaying, but combined with the overall global warming trend, it manifests as a pause in global warming that I anticipate lasting for 5-9 years. The difference in my extrapolations depends on whether I include the Atlantic Multidecadal Oscillation that some scientists believe isn't an oscillation at all, and that exhibits zero phase delay from SST temperatures. I'm suspecting that it's difficult or impossible to isolate AMO from AMOC, and that the Atlantic exhibits no substantial oscillations in sea surface temperature aside from the wide swings of apparent ringing that we saw during that unexplained pulse in 2023, so I'm trusting my model without AMO better than the one with.
I'd be interested in your interpretation of this result that I'm showing. I've posited on Gavin's RealClimate that maybe there's been some change in teleconnection between the surface ocean and the subterranean ocean that we've been hearing about lately. The pulsed warming has a much sharper attack than the cooling trend from Pinatubo, and also seems to have occurred simultaneously across all ocean depths. Another potential explanation is the collapse of the carbon sink in 2023-2024 and the biological implications upon ocean temperatures of that recent change.
Are there any answers yet? Can you incorporate a model of this pulsed warming in your analysis? The IPCC hasn't yet announced any consensus as to why this pulsed warming occurred.
To the best of my knowledge, IPCC hasn't even acknowledged that it is a pulse either, so my own result seems to be an original contribution to the science, even if the calibration may be off and the modeling may have systematic error. I'd like an informed opinion as to whether I've made a bona fide discovery of a warming pulse in my quest to understand the gobsmackingly bananas SST warming and Antarctic ice loss of 2023? If I have, those promoting recent acceleration from aerosols may find their claims confounded by the pause in warming that I'm attributing to the currently unexplained portion of recent abrupt warming that seems to have been a one-time occurrence rather than part of a long-term trend.
Details at the link below. I haven't yet posted a comparison between models that includes the one without AMO. I suspect that the inclusion of AMO in my model exaggerates the duration of the pulse because 9 years seems like a really long pause in an accelerating warming trend, but 5 years is a lot more believable. I'll be uploading another version without AMO and pinning it to my profile soon.
Since this pause is detected by subtracting the global effects of localized oscillation modes, it isn't directly observable in uncompensated normalized SST. Also, since the model is largely uncalibrated and may have systematic error, the decaying pulse may be an artifact of the model rather than real...but it sure looks real on a visually graphical level after detrending the compensated SST data. Visually compelling results like this seem to me authentic, especially given that I've also credibly detected the appropriate magnitude and duration of cooling from Pinatubo that I wasn't even looking for when I first began this investigation, as well as Chichon and associated eruptions pre-dating Pinatubo, plus maybe an earlier Hunga Tonga submarine eruption pre-dating the most recent one in 2022.
Thanks in advance for any insights you may apply to my result, or any elaboration you can supply on the 'missing factor' that your own analysis may not have taken into account, since there's no consensus yet on what caused the unexplained +0.2 degrees C of abrupt warming in 2023 that seems to have persisted past the end of the ENSO maximum but apparently hasn't caused any acceleration on its own:
https://bsky.app/profile/cheryljosie.bsky.social/post/3lei5c3upes2z
Great article Zeke! i tried to find any peer-reviewed articles that attempt a similar breakdown and came up empty. surely researchers have done this decomposition previously in other models? was hoping to be able to reference similar results from a more comprehensive ESM to back up these numbers... thanks!
It builds off the work done in the AR6, specifically Chapter 7, Figure 7.8: https://www.ipcc.ch/report/ar6/wg1/figures/chapter-7/figure-7-8/
There is also a more up-to-date version published in Forster et al 2024: https://essd.copernicus.org/articles/16/2625/2024/
Does there exist an attribution, like in the first chart, for the northern hemisphere? Given that aerosols predominantly affect the NH, we should have had a negative total forcing for most of the time there, only turning positive lately.
The rate of warming is the derivative of total warming, so the timing when aerosols switch from reducing to increasing the rate of warming depends on when aerosol emissions peak and start to decline rather than their magnitude.
What about instead of 'drivers' you examined the causes:
- short term thinking
- profit prioritisation
- overconsumption
- disconnection from nature
. . . and then the actual root causes which I've written about here: https://shorturl.at/psCTI
Excellent post as usual Zeke.
What did you think about Tamino's analysis of recent warming? https://tamino.wordpress.com/2024/12/07/too-hot/#more-12273
The correlation of the two piece linear fit with adjusted temperatures is striking. Of course just a statistical fit and the temperatures are adjusted.
For those interested in sulfate modifications of the atmosphere remember that volcanos decrease both temperature and precipitation. If your farmers get drought would you be very happy?
Great article Zeke! These charts show some interesting trends depicted very clearly. Thank you!
Is “solar output” just referring to very long term variation in solar luminosity? Or is it also taking into account variation in Earth’s orbit (Milankoch cycles driving recent ice ages)? Because the climate denier argument is to say “we’re still leaving the last ice age” so to refute that the expected temperature change as a function of Milankovich cycles must be included
Milankovich cycles have not changed over the past 150 years, they vary over tens to hundreds of millennia, so putting ~0.0001 w/m^2 into a model will give you no change (and, more broadly, represent a quite small external radiative forcing and rely extensively on feedbacks for amplification – including CO2! https://www.carbonbrief.org/explainer-how-the-rise-and-fall-of-co2-levels-influenced-the-ice-ages/)
Well sure Milankoch cycles haven’t “changed” much but the normal cycling I was referring to has big impacts on climate on the 20,000 to 100,000 time scales and are thus relevant to discussions about exiting the last ice age ~10,000 years ago, i.e., would the shorter precession and obliquity cycles, superimposed, result in warming or cooling now, absent changes in CO2? It wasn’t clear to me that the normal cycling of precession and obliquity were taken into account here, but maybe it was. This NASA link suggests our current position in the super imposed Milkanvich cycles would result in cooling, maybe that’s lumped into your “solar output” portions
https://science.nasa.gov/science-research/earth-science/why-milankovitch-orbital-cycles-cant-explain-earths-current-warming/
EDIT: I see your link discusses how the cycles are not really independent sources of warming/cooling, so I assume it would be difficult (meaningless?) to tease apart the orbital cyclicity while holding CO2 constant.. better I guess to see total aggregate cooling/heating net effect predicted today absent anthropogenic CO2…
A question: James Hansen has written several times in his blog in recent years that aerosols are still not being measured and that their contribution to warming is therefore unclear. He called for the amount and effect of aerosols to finally be measured.
In this article, the first diagram shows a very large error range for aerosols, which fits with Hansen's statement, but the other diagrams show exact numbers and curves without this wide error range.
So here's the question: contrary to Hansen's statement, are there precise measurement data on aerosols and their effect on temperatures from 1905 to today as shown in the two diagrams below?
We should be thankful for our current inter glacial warming - life thrives in it
Is a frog in a pot thankful for the nice warm water, before it comes to a boil?
The earth isn’t going to boil, only the inept UN and its arrogant child, the IPCC, peddle that nonsense because their continued taxpayer funding depends upon it!
"The earth isn’t going to boil..."
"Frog in a pot" is a metaphor. I didn't intend to imply you're an actual frog, either!
Yep, there it is: conspiracism, the last refuge of the paranoid denier. Zeke, do you and Andrew have a "Crank Shaft" à la RealClimate?
Does this mean when we see assumed temperature targets in the future like 2- 2.5 degrees we should add .5 degrees to it? Does this mean we're currently at 1.8C? Or is there something that balances this out as we reduce emissions?
Thanks!