When the Hunga Tonga–Hunga Haʻapai volcano erupted in January 2022, it immediately posed a problem—not merely scientific, but institutional. The eruption was the most explosive in the satellite era, injected an unprecedented quantity of water vapor into the stratosphere, and did so with a chemical signature unlike the canonical climate-cooling eruptions of the late twentieth century. It was followed, inconveniently, by a pronounced surge in global surface temperatures. The timing alone guaranteed scrutiny. What mattered was how that scrutiny would be framed.
The resulting assessment report is vast, meticulous, and technically competent. It documents the eruption and its atmospheric aftermath in extraordinary detail, particularly in its observational chapters. Satellite measurements are cross-validated, transport pathways mapped, and instrumental uncertainties repeatedly acknowledged. The early sections read as careful empirical science, and much of the observational synthesis is genuinely valuable.
But the report is not merely descriptive. From its opening highlights onward, it signals a specific destination.
“The record-high global surface temperatures in 2023/2024 were not due to the Hunga eruption.”
That sentence appears in the Highlights section, not buried in the discussion, and not framed as provisional. It is one of the few categorical statements in the entire summary. Its placement matters. In a scientific inquiry, conclusions typically emerge from analysis. In this document, the conclusion precedes it.
The report then devotes hundreds of pages to ensuring that this statement remains unthreatened.
To be clear, the authors do not deny that Hunga was extraordinary. On the contrary, they emphasize repeatedly that the eruption was unique in the observational record.
“The stratospheric hydration caused by the eruption was unprecedented in magnitude, altitude, and duration in the satellite record.”
That admission alone makes the subsequent dismissal of surface relevance nontrivial. Water vapor is not an exotic or speculative climate agent; it is the dominant greenhouse gas. An unprecedented perturbation at climatically sensitive altitudes is, at minimum, a legitimate explanatory candidate.
The report quantifies that perturbation carefully.
“Hunga injected an exceptional amount of water into the stratosphere, causing a ~10% (~150 Tg) increase in the global stratospheric water vapour burden.”
This is not a rounding error. Yet from this point forward, the analytical burden shifts. The question ceases to be what such an injection might plausibly do and becomes how its effects can be shown to dissipate, fragment, or sink below detectability.
Radiative forcing estimates are produced. The report arrives at a net top-of-atmosphere forcing of roughly −0.4 W/m² over the first two years, dominated by short-lived aerosol effects and partially offset by water vapor. From this, a small surface temperature response is inferred, followed immediately by a critical concession.
“As a consequence of the negative TOA RF, the Hunga eruption is estimated to have decreased global surface air temperature by about 0.05 K during 2022–2023; due to larger interannual variability, this temperature change cannot be observed.”
This sentence does more work than the report seems to recognize. An effect that cannot be observed, cannot be separated from noise, and cannot be detected empirically is not a finding; it is a boundary. It defines what must be ignored.
The report repeatedly emphasizes this indistinguishability.
“Surface climate impacts of the eruption… are relatively small and not distinguishable from the background internal variability of the Earth system.”
Internal variability thus becomes a one-way gate. It is sufficient to dismiss Hunga’s influence, but it is not subjected to the same analytical pressure as an explanatory mechanism in its own right. Variability explains by default; Hunga must explain beyond reasonable doubt.
This asymmetry is reinforced through modeling. The report leans heavily on global chemistry–climate models, repeatedly stressing their importance.
“Models are critical tools to elucidate the detailed chemical, radiative, and dynamical impacts on the Earth system from volcanic events, especially in the context of interannual variability.”
Yet these same models are acknowledged to diverge in key respects.
“Models differ in their simulations of Hunga aerosol microphysical properties, indicating that simulating aerosol microphysics remains a challenge for model development.”
Differences in aerosol growth rates, sedimentation, cross-equatorial transport, and decay times are treated as technical hurdles rather than epistemic warnings. Model spread does not weaken conclusions; it merely motivates more modeling.
When transport-driven ozone anomalies are discussed, the report concedes limits to causal attribution.
“The extent to which transport anomalies were causally connected to the eruption is not clear.”
This admission is quietly devastating. It acknowledges that large observed anomalies coincided with Hunga but cannot be cleanly attributed to it. Rather than opening the possibility that attribution itself may be structurally weak, the report uses this ambiguity to cordon off surface relevance altogether.
The same pattern recurs in the discussion of circulation effects.
“In the NH, observed stratospheric meteorological conditions following the Hunga eruption were within the range of interannual variability, and model simulations show no consistent circulation response.”
No consistent response becomes synonymous with no meaningful effect. The possibility that the climate system simply lacks the resolution to isolate short-term forcings of this type is never seriously entertained.
Perhaps the most revealing sentence in the entire document appears not in the science chapters but in the forward-looking institutional context.
“Models are critical tools to elucidate the detailed chemical, radiative, and dynamical impacts on the Earth system from volcanic events, especially in the context of interannual variability.”
This is less a methodological statement than a declaration of dependence. Where observations fail to resolve attribution cleanly, models are invoked to close the question.
The report also makes clear that its remit extends beyond pure inquiry.
“This report has aligned closely with… upcoming international assessments.”
That alignment explains much. An open-ended conclusion—that a large, natural, poorly constrained event may have contributed meaningfully to recent warming—would complicate attribution frameworks that depend on trend continuity. Ambiguity was not an acceptable endpoint.
Instead, the hypothesis is exhausted. Not falsified, but procedurally neutralized. Every plausible pathway is examined, attenuated, and shown to fall below detectability thresholds. Uncertainty is acknowledged, but always in ways that weaken the Hunga hypothesis more than its alternatives.
The length of the report is not incidental. A short paper declaring Hunga irrelevant would have invited skepticism. Only a document of this scale—dense with data, models, intercomparisons, and caveats—could plausibly declare the case closed without appearing dismissive. The volume itself functions rhetorically, conveying finality through exhaustion.
None of this requires accusing the authors of misconduct. The report is careful, internally consistent, and often admirably cautious. But caution is not evenly distributed. Skepticism is applied asymmetrically. One explanation is forced to clear a high evidentiary bar; others pass unchallenged.
In that sense, the document reads less like an open scientific inquiry and more like a legal brief. Evidence is marshaled, counterarguments anticipated, uncertainties catalogued, and a verdict delivered early, then defended at length. The goal is not discovery, but closure.
The Hunga Tonga eruption presented an opportunity to examine the limits of short-term climate attribution and to confront how much natural variability remains unresolved. Instead, it became a case study in how institutions respond when nature threatens to intrude on a preferred narrative. The report succeeds on its own terms. Whether those terms serve science—or merely its administrative needs—is the question it never seriously asks.
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From the above, IMHO, overall excellent article:
“It is sufficient to dismiss Hunga’s influence, but it is not subjected to the same analytical pressure as an explanatory mechanism in its own right. Variability explains by default; Hunga must explain beyond reasonable doubt.”
In response and supporting the article’s overall thrust, there is this “analytical reasoning”:
“When Hunga Tonga–Hunga Haʻapai, an underwater volcano near Tonga in the South Pacific Ocean, erupted in 2022, scientists expected that it would spew enough water vapor into the stratosphere to push global temperatures past the 1.5 C threshold set by the Paris Accords. A new UCLA-led study shows that not only did the eruption not warm the planet, but it actually reduced temperatures over the Southern Hemisphere by 0.1 C.
“The reason: The eruption formed smaller sulfate aerosols that had an efficient cooling effect that unexpectedly outweighed the warming effect of the water vapor. Meanwhile, the water vapor interacted with sulfur dioxide and other atmospheric components, including ozone, in ways that did not amplify warming.”
— “Hunga volcano eruption cooled, rather than warmed, the Southern Hemisphere”, Holly Ober, April 2, 2025 (my bold emphasis added), https://newsroom.ucla.edu/releases/hunga-volcano-eruption-cooled-southern-hemisphere , with an embedded hyperlink to the full text of the UCLA-led study publication of March 2025 in Nature: Communications Earth & Environment that is available at https://www.nature.com/articles/s43247-025-02181-9 .
This goes a long way toward explaining the fact that UAH satellite-based measurements of GLAT temperatures only began to rise above the UAH satellite-established trend line some 14-16 months AFTER the HT explosion and injection of water vapor into the stratosphere.
Do you think UCLA would have more credibility is they had reported their 0.1C cooling likely, but 0.1C warming possible but less likely? What a joke. What would the response time had to have been for UCLA to come to some other conclusion?. See below “climate-related disasters”? Not extreme weather events? I live in California I see the institutional alarmism.
California Climate Action Grants: UCLA-led projects have received $7.5 million in state-funded grants through the University of California’s Climate Action initiative. These grants support research on climate change impacts, electric vehicle adoption, energy storage, and health and safety for workers responding to climate-related disasters. The program overall allocated $185 million for UC climate initiatives, with UCLA among the major beneficiaries. [newsroom.ucla.edu]
Reply to ToldYouSo
HTTH volcano
Observed global temperature anomalies didn’t spike immediately; instead, some datasets show subtle changes appearing 14–16 months later.
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The eruption also released sulfate aerosols, which reflect sunlight and cause cooling. Initially, these offset the warming from water vapor.
Delayed Signal: Climate systems have inertia—ocean heat uptake and atmospheric mixing can delay the manifestation of net effect.
Current Consensus Most peer-reviewed studies still lean toward net warming from the water vapor injection.
Not only is the UCLA study wrong, it’s shameful intentional misleading bias that deserves at least a slap on the wrist for malfeasance, not being referenced as a dynamic research discovery IMHO.
Ditto. The study never said what caused the heat spike.
Uhhhh . . . maybe, just maybe, that is because that was never the purpose of the study.
ROTFL!
Exactly.
The strongest yearly amplitude variation of energy input to Earth results from Earth’s elliptical orbit around the Sun, where the solar insolation at aphelion (July 3, 2025) is about 7% less than at perihelion (January 3, 2026).
The coldest days (lowest temperatures of the lower atmosphere) in the Earth’s southern hemisphere, which has far larger percentage of ocean surface area than does the NH, typically occur in the months of July and August (ref: https://earthsky.org/earth/why-isnt-the-longest-day-of-the-year-the-hottest-day/ )
This indicates that the Earth has a delay factor of at most around 60 days in responding to a change in forcing (i.e., beginning of increase in solar insolation on July 3 versus beginning of lower atmospheric warming at, say, end-August), and this despite the large surface area of water beneath that atmosphere which contributes to causing that delay.
So, yeah, there is a characteristic delay time in Earth’s climate system even when consideing the thermal inertial of its oceans . . . it’s around two months or less . . . NOT 14-16 months.
off topic, not applicable to temperature response from HTHH
Really, if HTHH did not affect the balance between energy arriving and energy leaving the Earth’s TOA—exactly as does Earth’s annual variation from the Sun—then please explain how its injection of water vapor into the stratosphere WAS able to to do so, especially explaining the cause of the asserted delay of 14-16 months in rising GLAT as measured by UAH using satellite data.
So easy to just merrily assert claims . . . so often impossible to logically and objectively support such claims.
Seasonal lag is not the same as climate inertia. The two-month delay you cite reflects short-term surface warming after solstice, not the global response to a sudden radiative forcing change.
Volcanic aerosols and ocean heat uptake operate on much longer timescales because of deep ocean mixing and feedback loops. That’s why major eruptions like HTHH show peak temperature impacts 12–18 months later, not weeks:
https://doi.org/10.1029/1998RG000054 Large volcanic eruptions inject sulfur gases into the stratosphere, which convert to sulfate aerosols with an e-folding residence time of about 1 year. Large ash particles fall out much quicker. The radiative and chemical effects of this aerosol cloud produce responses in the climate system.
The warming after the July 3 solstice continues continuously for the next six months until the occurrence of the January 3 solstice.
BTW, the atmospheric warming associated with a 7% increase in solar insolation at TOA from aphelion to perihelion amounts to about 2*0.035*1360 W/m^2 = 95 W/m^2 total variation, the solar constant being defined at 1 AU, the mean distance between aphelion and perihelion.
This change in incoming power flux can be compared to various estimates that put the impact of the Hunga-Tonga eruption in the range of ± 0.5 W/m2, with most science publication now agreeing on an overall net decrease of radiation flux reaching the ground . See
https://pmc.ncbi.nlm.nih.gov/articles/PMC11949836/
and
https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2024JD041296.
That’s nicely asserted, but in the particular case of the HT eruption of January 2022 versus UAH measurements of GLAT, the atmospheric temperature only departed above the trend “noise level” 14-16 months later and even then only reached its most recent peak in the first half of 2024 . . . that would be an interval of, yeah, more than 24 months after the eruption. So, if you meant to imply the e-folding was positive, then the peak required 2 e-foldings . . . pretty weird since the stratospheric water vapor was claimed to be dissipating from the moment it was injected by the HT eruption. Alternatively, if you meant to imply the e-foldings would be negative, then they could not have ever caused a resulting increase in temperature, ONLY a decrease.
You see, it matters little what I asses the credibility of the UCLA-led study team and their findings to be.
What matters—and you apparently choose to overlook—is that the editors at Nature chose to publish it in their scientific journal Communications Earth & Environment.
I didn’t bring UCLA into the discussion, I simply pointed out how worthless, biased, and alarmist there senseless drivel is .
Do you not see the obvious contradiction between “I didn’t bring UCLA into the discussion” and “I simply pointed out . . . their worthless . . . drivel”.
ROTFL!
It looks like an attempt to discount water vapor.
True — it never said what caused the heat spike.
If you cared to look into the title and purpose of the UCLA-study publication in Nature that I previously referenced—and in this thread’s context believe it be the “it” to which you refer in you comment immediately above—you will find its title is “The January 2022 Hunga eruption cooled the southern hemisphere in 2022 and 2023” (https://www.nature.com/articles/s43247-025-02181-9 ).
Nowhere in this publication does one find that the study team had the purpose of discovering the cause of the UAH-measured “temperature spike” that peaked in the first half of 2024.
Thank you for writing this, I have a few questions on that topic and the literature I could find seems lacking.
Global Climate Models seem to show the believe of the caster more than anything. I point to the unrealistic results of some high-CO2-sensitive climate models in the CMIP6-frsmework while compareable models in CMIP5 and older were found accurate and skillful. This not only shows those model to produce fantasy results in the later generation, but also casts massive doubts on established model testing procedures, as we now know for certain that wrong models slipped through the tests earlier, clearly the uncertainty accessment is insufficient for those and all other tested models.
For the Tonga aftermath an observation published by K. Emmanuel and others seems brelevant: An often observed anti-correlation of Stratospheric cooling and Tropospheric warming.
One general idea is that the Stratosphere is cooling when additional radiative pathways are generated by additional greenhouse gases, which is omnidirectional and thus generates warming for the lower air (alarmists point to the addition of CO2, but the idea should hold for the Tonga water)
I haven’t read that report yet, but any publication which does not include an estimate of that effect under various feedback scenarios seems worthless.
The other question is how these models which explain the recent warmer years mostly by greater internal variation of Earth climate fare for long-term trends.. I am guessing they should generate large uncertainty in global trends (temperature, percolation, extreme weather.. you name it) andvthus represent a huge step back for model based predictions!?
Well, they are probably about right, considering the additional stratospheric water vapor then had more molecules emitting both up and down and the lower troposphere has more water vapor molecules to absorb said IR….not to mention a surface to absorb most of the remaining downward headed IR.
However, what they are really missing is that the Sun’s heat input to our atmosphere and the surface causes “temperature” but also converts to the kinetic energy of convection and advection (winds). That stored up energy of air motion, and its daytime addition and nightime dissipation don’t make it onto energy budget diagrams (while SB fore and back radiation do)
“Total atmospheric column kinetic energy” per sq.M is built up and half (or so, very variable) is dissipated between the daytime and nightime input of sunlight.….on the order of kilowatts per sq.M of surface…..
Consequently -0.4W/m² is of little effect. So little, in fact, that it is like analyzing baseball homerun statistics for a correlation to player’s diet….realistically none if your stats are all major leaguer’s to start with… but maybe well fed players hit the odd extra one over the fence…..and by starving a few players in the name of science until they are weak you can probably confirm your pre-conception in a peer reviewed paper…
NOAA Earth System Research Laboratory reports specific and relative atmospheric humidity measurements by balloons for near the surface, 4.2 km altitude and 9 km altitude dating back to 1948. This data can be found at climate4you.com under the climate+clouds button. Only one data set, 4.2 km altitude – specific humidity, shows a modest increase following the Hunga Tonga Hunga Ha’apai eruption in January 2022. The observed increase occurred over a 2-3 year period following the eruption and amounted to an increase of about 0.2 gm/kg out of a range of about 1.8 to 2.4 gm/kg, roughly 10%. However, neither the specific humidity near the surface nor at 9 km altitude shows such any such change. A similar increase is shown for the years 1956 through 1958 at all three altitudes following a comparable dip during the prior few years. For a 7 year period beginning about 1975 to 1982 a larger but slower increase is shown for the 9 km data set, but not for the 4.2 km or near-surface data sets. Overall, specific humidity numbers have been wiggling about since 1948. To the contrary, relative humidity values have been declining since 1948, quite dramatically at 9 and 4.2 km altitudes and slightly near the surface. It seems that atmospheric humidity has its own masters which we do not understand.
I just recently found out that NOAA has modified some of these old radiosonde based data sets. I suspect the same ones referenced by climate4you. I’d not put much confidence in that data. See section 4.7 in ….
https://scienceofclimatechange.org/wp-content/uploads/Miskolczi-2023-Greenhouse-Gas-Theory.pdf
how that scrutiny would be framed.
Enter the media- eg the BBC
This water also clearly played a role in creating the conditions necessary to generate the “greatest concentration of lightning ever detected”,
https://www.bbc.co.uk/news/science-environment-63953531
I’m tempted to predict a correlation in the number of wildfires, but I won’t.
The report accomplishes what it set out to show:
As Charles Rotter reports, “No consistent response becomes synonymous with no meaningful effect. The possibility that the climate system simply lacks the resolution to isolate short-term forcings of this type is never seriously entertained”.
Mission accomplished,
1) It’s not water vapor, so it has to be CO2.
Meanwhile any honest appraisal of what the UAH anomaly graph shows is that the warming and subsequent cooling tracks HTTH (but that does not provide “proof” in a legal sense)
2) Since the volcano injected water vapor into the Stratosphere now, it certainly suggests that it wasn’t the one and only time in the last million years.
The absence of any evidence of earlier such sub sea eruptions of comparable magnitude in the historic geologic record must be discounted away as insignificant as it threatens the accuracy of everything else promoted by the CO2 as Climate Control Knob by the climate consensus cult.
3) This is very complicated, send more money for modeling so we can get the answers.
Here’s what really happened:
The reporting agency knows it, we know it, and anyone paying attention knows it, but the climate alarmist industrial complex feeding off Cap and Trade, agencies relying on government funding, and grant seeking universities don’t want to hear it, so they don’t hear it.
OK, please get back to me when your asserted certainty of events and your science-based certainty of the asserted physical processes that you list has been published (outside of WUWT or a vanity website) for all to review.
Hint for you: I do believe you’ll need to provide quite a bit more details regarding what “really happened” than you did in your post above in order to be taken seriously.
“Evidence is marshaled, counterarguments anticipated, uncertainties catalogued, and a verdict delivered early, then defended at length. “
Isn’t that exactly what a scientific enquiry should do? Your objection is not to the method but to the conclusion. But you can’t say why the conclusion is wrong.
“Water vapor is not an exotic or speculative climate agent; it is the dominant greenhouse gas.”
Water vapor in the troposphere is the dominant greenhouse gas. That is where the greenhouse effect is happening. Not in the stratosphere, where there is very little water. So a 10% increase is not such a big deal. 150 Tg (=15 Mtons) of water is, by the standards of GHG emissions, a small mass. We put that much C)2 in the air every few days.
“It was followed, inconveniently, by a pronounced surge in global surface temperatures.”
But, inconveniently, the timing did not fit. The change to the strtosphere was immediate, in Jan 2022. No surge happened until mid 2023.
“”Not in the stratosphere, where there is very little water. So a 10% increase is not such a big deal. “”
Not big compared to what? The total CO2-effect is below 1% of the solar effect.
Isn’t the question how much surface warming could come stem this stratospheric change and did they really consider/present the strongest possible result?
What I see reported here looks to.me like a series of assumptions to maximize all other possible contributions rather than an honest attempt to qualify the possible warming range from the eruption.
So in policing terms –
“it’s a fit-up”?
Wrong. That’s just where the radiative effect is most dominant.
I have no idea how studies like this are conducted. My question is did they gather good measurements and evidence. If they did and our side had that information how would they have conducted the study? Did they evaluate the other stuff sent into the atmosphere by the eruption? It is my understanding that volcanic eruptions blow lots and lots of CO2 into the atmosphere, does that still happen with underwater eruptions? If they have good measurements and data/evidence why would models be so important? This study appears to be less than helpful.
Once again I find greenhouse efficiency insights by Willis to be informative.
https://wattsupwiththat.com/2025/01/22/greenhouse-efficiency-2/ (see figure 3, greenhouse efficiency)
Notice the big drop and subsequent increase right after the 2022 eruption for the greenhouse effect. I suspect the big drop was caused by the sulfate aerosols reflecting extra solar energy to space even as clouds thinned over the same time period. Then it appears the aerosols dissipated and allowed the cloud effect to take over along with El Nino.
I’m of the opinion the water vapor change is a red herring. The real issue is the reduction in clouds. It was suppressed for about 1.5 years and then became the biggest factor.
In UAH data, we can see the cooling after the end of the El Nino in 2024 was fairly mild (only 0.2 C after 6 months). I think that tells us the El Nino itself was fairly weak. If so, that puts the Hunga-Tonga warming effect at around 0.5 C.
This would also tell us the cloud effects have not yet ended and could continue on for who knows how long.
There’s only 3 problems with climate “science” –
the probity, the provenance, and the prosecution of the selected (usually cherry-picked) climate “data”.
This paper demonstrates the Prosecution problem, as Charles highlights, by announcing the conclusion of cause-effect BEFORE presenting the rationale of the conclusion.
Judges often deliver their sentencing remarks in this fashion after the jury has handed in a guilty verdict, detailing what a p.o.s. the perp is, and what horrible things he / she / they did.
But climate “scientists” aren’t judges.
They just think they are.
If the HT eruption and sudden major pulse of water vapor didn’t cause the spike, then the only other candidate is El Niño. The 1997-98 el niño caused a similar-sized spike, but he was a monster El Niño. Do the authors feel that our modest el nino after HT could have caused it? If it is to be tak3n as a CO2 warming signal, why so pronounced, rapid, sudden, and out of nowhere?
Something to take note of is that during the satellite era, the UAH lower-troposphere temperatures have not had an El Nino spike of similar magnitude with a similar full-width, half-maximum. That is, this is the widest pulse observed in the UAH time-series coincident with an El Nino event. While they claim to have eliminated the HT eruption as being responsible for the strong warming, they have not explained the anomalous behavior (width) of this pulse.
We’re looking at such a minuscule time frame, we don’t even know what normal is.
NB : “The climate” is complicated, with many factors interacting in unknown ways. I think “only” should be replaced with “most likely” here.
.
One of my (many) “idle curiosity” spreadsheets plots various aspects of the UAH (lower troposphere, V6.1) versus ENSO/SOI (I use ONI V5, which is based on ENSO-3.4 anomalies) and changes in CO2 levels (at Mauna Loa, delta-CO2[X] = MLO[X] – MLO[X – 12 months]).
A copy of the graph with data updated to November 2025 is attached below (starting in January 1997, with a “stretched” X-axis to help visibility).
Notes
1) The timing is usually “ONI then UAH then delta-CO2”, with visible gaps (on the timescale used in this graph) between each “peak”. See the reactions to the 1997/8, 2009/10 and 2015/6 El Ninos for some clear examples of this phenomenon.
The UAH “reaction” to the 2023 rising edge of ONI was almost immediate instead.
2) The UAH falling slopes of large pulses usually have roughly the same amplitude — with the vertical scalings chosen by me for the graph below — as the preceding ONI falling slopes (e.g. 1998 and 2010), though this is not always the case (e.g. 2016).
There is a noticeably larger “inertia / pulse stretching” effect on the UAH curve in the fall from its peak at the beginning of 2024.
.
My “gut reaction” — which is almost certainly either “very” or “completely” wrong ! — when seeing the versions of this graph in the first half of 2024 was that the HTHH eruption had somehow “primed the pump” of the Earth’s climate system to that the next “large” El Nino, which duly occurred at the beginning of 2023, would “trigger” a large and rapid response in the UAH (LT) numbers at that later date.
The latest version (attached below) reinforces the idea that there is something “hanging around” that is slowing down the “normal” UAH falling edge (which should “probably” have got back down to its end-2022 level around this time last year ?).
The main problem with this conjecture is that I am unaware of an actual physical mechanism that would be a viable candidate for the “pump” being posited …
Boldly spoken but unprovable . . . as if humans truly understand all the variables that go into affecting the month-to-month swings reflected in the UAH tracking of global (let alone regional) lower atmospheric temperatures.
Maybe no one really knows what is going on. Nature does not seem to cooperate with any model or assumption. It remains too complex a system to anticipate. I think Willis has the best explanation out there. One thing is apparent–there is no climate crisis. Free The Carbon!
No one knows. Everyone has WAGs.