Australia Bushfire Smoke Now Warming the Lower Stratosphere? March 2020 Update

April 1st, 2020 by Roy W. Spencer, Ph. D.

Last month I noted how the global average lower stratospheric temperature had warmed considerably in recent months, especially in February, and tentatively attributed it to smoke from the Australian bushfires entering the lower stratosphere. You can read more there about my reasoning that the effect was unlikely to be due to the recent Taal volcanic eruption.

Here’s the March 2020 update, showing continued warming.

The effect cannot be as clearly seen in regional averages (e.g. tropics or Southern Hemisphere) because those regions routinely see large changes which are compensated for by changes of the opposite sign in other regions, due to strong adiabatic warming (sinking motion) or cooling (rising motion) in the statically stable stratosphere. Thus, global averages show the best signal of something new going on, even if that something new is only occurring in a specific region.

62 Responses to “Australia Bushfire Smoke Now Warming the Lower Stratosphere? March 2020 Update”

Toggle Trackbacks

  1. skeptikal says:

    The Southern Hemisphere had a sudden stratospheric warming event around 6 months ago (spring in the SH)… maybe it’s just the Northern Hemisphere’s turn now (spring in the NH).

  2. ren says:

    Frosty air will hit the west coast of North America. Far to spring in Washington state.

  3. Snape says:

    Dr. Spencer

    I quoted from this link last month:

    [thermal cameras can detect heat through smoke, and are widely used by firefighters for this purpose. Soot particles in smoke effectively block visible light, but allow infrared radiation to pass through, letting firefighters or other first responders navigate through smoke-filled environments.]


    From this, it follows that smoke has the opposite effect as greenhouse gasses…. blocking sunlight from reaching the surface and, at the same time, allowing free passage of upwelling LWIR.

    So it makes sense that smoke has warmed the stratosphere (absorbs sunlight), but why do you think it has warmed the surface?

    • Amazed says:

      From your comment, it follows that you have no clue.

      • Robin says:

        So why not give us the benefit of your knowledge?
        Not all of us are rocket scientists – or even climate scientists.

        • Amazed says:

          My advice is to learn some basic physics. Good enough?

          • Strop says:

            Hi Amazed,

            My advice is to learn some basic manners. From your comments, it follows that you have none. 🙂

            If you think someone hasn’t a “clue” then you can either take the opportunity to afford them your great knowledge or simply not take the opportunity to insult them.

            My theory is the inability to fulfill the first option usually results in the opposite of the second option.

            With regard to Snape’s question I haven’t a clue either. So I’d appreciate your proving my above theory wrong so I can be educated twice by your one kind gesture.

            Thank you.

          • Amazed says:


            I don’t care what you think, so I’ll ignore your advice. It’s stupid, anyway.

            Learn what a theory is, if you feel like it.

            I’m not sure why you seem to take pride in being as clueless as Snape, but I suppose you have your reasons,

          • Strop says:

            Hi Amazed
            re: your reply April 2, 2020 at 1:28am (I reference this because there was no “reply” button below that message and this may appear out of sequence)

            I’m not sure why you thing I take pride in being “as clueless as Snape”. There’s a difference between admitting something and boasting about. I was simply admitting.

            Given your response it seams my theory still holds. Thank you.

            It seems my use of the word theory was also appropriate.


            The word ‘theory’ has several meanings:

            a guess or speculation
            a law about things which cannot be seen directly, such as electrons or evolution
            a whole system of laws and hypotheses which explain many things.
            a field of study

            These meanings can “shade into each other”. Another source offers:

            hypothesis, but not verified
            systematically organised knowledge

            A theory in science (in contrast to a theory in layman’s terms) is “a logical, systematic set of principles or explanation that has been verifiedhas stood up against attempts to prove it false”.[3] For example, Darwin’s theory of Evolution is a system of ideas that points to humans and apes having evolved from a common ancestor. This conclusion is based on evidence that supports it.


          • Amazed says:


            So is your supposed theory a guess, speculation or what? Do you really expect someone to care whether your speculation is wrong? Why would you think I would care?

            You have admitted you are clueless, so I won’t waste my time asking you to prove you understand physics. If you cannot be bothered learning for yourself, that is your choice.

          • Strop says:

            Hi Amazed,

            Your caring about my theory is not relevant to the conversation and wasn’t even contemplated or implied by me. From my perspective it’s nice to not be shown to be incorrect and your actions have supported that. Which is why I thanked you.

            Why would you even contemplate the notion of asking me to prove I understand physics when I said I didn’t? Odd. My knowledge of physics is not on trial because I didn’t pretend to have any, like you are pretending to. It’s your knowledge that’s in question.

            You took the time to insult someone and (as it still appears) to pretend to have knowledge of something you obviously don’t. You also pretend to not be inclined to waste time, so you can pretend that’s a reason you’re withholding knowledge that you don’t have, yet you have time to waste engaging in a conversation such as this.

            As for “learning for yourself”. You think Roy didn’t have a physics teacher? But don’t worry. I’ll research what I can for myself because I know you won’t be able to offer the explanation Snape requested anyway.

            Please consider the original point which was about refraining from commenting if it’s only to offer an insult.

            Not doubt this conversation has been a nice waste of time for the other readers. I’ll end my part of it.

          • Mikey says:

            I think we should be allowed to upvote comments! I would like to upvote ‘Strop’. I only have a basic understanding of physics, so when I pose a question (such as on YouTube) I too get shot down by some numpty who ‘thinks’ he (with the benefit of distance via a keyboard) is big and brave enough to berate me for my lack of understanding – while at the same time actually failing to explain anything. I too, get the comment – ‘You haven’t a clue’. Indeed, I’ve probably already stated that I don’t, that’s why I was hoping for an explanation. Instead, all I get is some big brave man who knows he is safe (from getting a smack in the mouth)* and insults.
            *No, I’m not advocating violence, I’m merely pointing out that, standing face to face in a bar, that big brave man (yes, that’s you, ‘Amazed’) wouldn’t be so brave. At least make an attempt to being courteous, even if your parents never taught you any manners at all.

          • Amazed says:


            You admit to being clueless, and lacking knowledge, but claim to be more knowledgeable than I in the same breath! Typical alarmist fool who resorts to feeling insulted or demeaned when exposed to reality.

            The usual nonsense. Climate science is as much science as are political science and social science. As to rocket science, show me a university degree in Rocket Science! I know, I know, you didn’t mean to be taken literally, I suppose.

            If you choose to feel insulted, why should I care? Does anyone else care if an anonymous self admitted clueless person feels insecure? Learn some physics and correct me if I err. I wont feel insulted. Grateful, more like it.

          • Amazed says:


            If you are truely as clueless as you claim, do you really think that you can learn physics by asking for explanations from anonymous commenters? Obviously. It demonstrates your stupidity. Heres a hint – try textbooks or Google.

            As to bar fights, I leave those to you. Make sure you remain courteous, and remember its bad manners to complain you only got flogged because the guy you picked on didnt fight fair.

          • spike55 says:

            So funny,

            Amazed has proven that he is clueless, by his abject inability to produce anything other than bluster..

            He still hasn’t put forward anything in the way of physics or knowledge.

            He say “correct him”, yet has has only made empty comments.

          • Amazed says:



          • Mikey says:

            Amazed: I’m certainly not going to waste any more time on someone as puerile as you, and with someone evidently lacking a basic grasp of social etiquette on a forum. And I’m hardly ‘stupid’ – I’m an engineer, an expert in my particular field, and with an IQ of 132, but I’m not surprised you made that mistake. I guess you’ve gone through life in your crass way, and I’ve no doubt you often wonder, sitting alone in your room, why it is that you have no friends (or wife/girlfriend). I’ll leave you to carry on blustering. There are too many people like you in the world, and they make it a less-pleasant place.

  4. DMacKenzie says:

    Dr. Roy, Isnt the decline in lower stratospheric temperature over the last 35 years also the logical outcome of the increasing CO2 levels ?….the increased CO2 emitting more IR to outer space. Are those numbers scientifically reasonable compared to the troposphere numbers you work with ? Sorry, Im wandering off the fire and volcano topic a bit…but couldnt help but notice that temperature decline.

    • Roy W. Spencer says:

      John Christy has compared our lower stratospheric temps to the CMIP5 climate models and the average of the models match the observations almost perfectly. I believe the cooling trend is some combination of increasing CO2 and ozone depletion.

      • DB says:

        From Thompson and Solomon, “Understanding Recent Stratospheric Climate Change”

        The lower stratosphere has cooled by a globally averaged ~0.3-0.5 K/decade since 1979. The global-mean cooling has not occurred monotonically, but rather is manifested as two downward “steps” in temperature, both of which are coincident with the cessation of transient warming after the major volcanic eruptions of El Chichon and Mt. Pinatubo.

        The lower stratosphere has not noticeably cooled since 1995, which indicates that the trends in this region are not dominantly controlled by the known increases in carbon dioxide over this period. Attribution experiments indicate that the long-term cooling in global-mean lower stratospheric temperatures is driven mainly by changes in stratospheric ozone.

      • barry says:

        Solomon and her fellow researchers agree with Roy Spencer, DB. From the article:

        “The warming of the stratosphere since the eruption of Mount Pinatubo is largely driven by the recent increases in global-mean ozone. In fact, when the linear relationship with ozone is regressed from the data, stratospheric temperatures have decreased since the eruption of Mount Pinatubo. The decreases in the residual temperature data since the mid-1990s can be interpreted as reflecting physical processes other than ozone depletion and are broadly consistent with the predicted impact of increasing greenhouse gases (Shine et al. 2003; Ramaswamy et al. 2006).”

        And this is a consistent theme across other articles she has written, though her papers tend to focus on ozone and the Dobdon-Walker circulation in stratospheric temperature evolution.

  5. Stephen Paul Anderson says:

    Maybe whatever is causing the volcanic eruption is causing the lower stratosphere warming or whatever is causing the lower stratosphere warming is causing the volcanic eruption?

  6. Stephen Paul Anderson says:

    Is causing the brushfires too?

  7. Stephen Paul Anderson says:

    And, causing CO2 to be on an upcycle?

  8. ren says:

    Very low temperature in the west of North America.

    • pochas94 says:

      What do you think about that? Could rays precipitate ice crystals? Just being provocative.

      • ren says:

        Yes, because the high temperature in the lower stratosphere allows water vapor to escape into the stratosphere. Thank you for the wise question.

      • pochas94 says:

        The stratosphere begins at about 20 km and goes up to about 50 km. Noctilucent clouds occur even higher, 76 to 85km. So water vapor ice is definitely present in and even above the stratosphere.

  9. coturnix says:

    oh… is this an april fools joke? How can a smoke, which isn’t even supposed to get past 4 km, can possibly warm stratosfere?

    • Roy W. Spencer says:

      coturnix, apparently you aren’t aware that NASA’s CALIPSO satellite Lidar data showed the smoke going into the stratosphere:

      • coturnix says:

        Nice, a reply from dr Spencer himself… no offence, but i hate april fools and consider anything published on that date to be a B.S. fake unless proven otherwise. Hence, the tone of my comment.

        Also, how can a smoke rise up so high? it was my understanding that dry convection only spreads withing the boundary layer, that even over hot deserts doesn’t extend more than 4 km above ground. Elsewhere, to ge into the upper troposphere, the air must go through the moist convection, which as I understand should wash out most of not all of the smoke out of it. Or at least, teh sulfates and the ashes are hydrophobic so those should be gone.

      • ren says:

        January 22, 2020
        NASA Satellites Observe Smoke Transport into the Stratosphere from the 2020 Australia Fires
        What has changed since January 22?

      • coturnix says:

        Ok, 1) meant ‘hydrophilic’ in the previous commenta, and 2) also i think i am wrong as i did forget about transport along the extratropical cyclone conveyor belts. As i understand, they are rather low on convection, therefore it may be that particulates would not be all soaked and removed out of the atmosphere.

  10. ren says:

    Meanwhile, the subsurface temperature in the equatorial Pacific begins to decline.

  11. ren says:

    Both solar polar fields have already reached their peak, which marks the beginning of the new 25 solar cycle. The spot has now appeared in the northern solar hemisphere.
    The North Polar Field may have peaked at the end of 2019, while the South Polar Field peaked in November 2015.

    • Appe.ll says:

      In fact, the climate is very insensitive to changes in global solar irradiance.

      dT/T ~ dS/4S

      where T = surface temperature, S = solar irradiance.

      Plug in the numbers.

      dT <~ 0.1 degC/(W/m2)

  12. Snape says:


    [Also, how can a smoke rise up so high?]

    I think the intense heat from the flames probably explains this.

    • coturnix says:

      Hardly a scientific explanation. The temperature of the flames could be as high as 1900C (from wikipedia), which theoretically should allow the flames to rise half way to the ISS [10K per km for air would give 190km rise, but the flames were probably more dense as co2 definitely dominated water vapor in them], but they didn’t. If they didn’t, then how do you know that they rose 10 or 20 km? Because it means that there were factors affecting the flames such that they didn’t realize the full potential of 190km that they could have risen to, then how do you a priori constrain such constraining factors?

  13. Snape says:

    And maybe water vapor coming from the trees and vegetation as they burned.

  14. angech says:

    At last.
    A “real” hot spot found.

  15. Snape says:


    You bring up an interesting question, when and where is it appropriate to use a standard lapse rate?

    • Amazed says:

      When you are not concerned with reality. The measured change in temperature with altitude will only agree with the modelled lapse by accident. Marginally more useful than the fact that a stopped watch is absolutely accurate twice a day, I suppose.

      The average family in the USA comprises 3.14 people. More or less useful than the standard (average) lapse rate?

    • coturnix says:

      If the smoke rises without mixing, and fast enough not to experience significant radiative cooling, its temperature would fall along the dry adiabate for that particular gas mixture that forms smoke, also taking into the account the fact that the heat capacity of gases may change with temperature. In reality, neither of those conditions hold place, smoke will probably cool radiatively, and it will mix with the surrounding air. Question is to what extent? I suppose it may be possible that the smoke from a fire with a horizontal extent much larger than the height of the troposphere will experience only limited mixing in of the surrounding cool air, and will rise much higher than one would normally expect. I’m not sure we could know that exact height from just back of envelope calculations.

    • coturnix says:

      On a second thought maybe it won’t follow the dry adiabate at all, since that is calculated for homogenous atmosphere. It would follo some kind of adiabate though.

  16. Snape says:

    I had a stopped watch that was accurate five or six times a day. Go figure.

    You could be right about the lapse rate.

    • Amazed says:

      Five or six? Don’t know? You are an idiot. The lapse rate is what it is. Do you think your approval makes any difference to anything at all?

  17. Strop says:

    Hi Amazed,

    I wasnt going to comment further but I should correct a couple of your thoughts about the conversation.

    Regarding your comments about sciences, rocket science, climate science, being literal. I didnt make any reference to rocket science, climate science etc. I think youre incorrectly attributing comments by others to me.

    As for my admitting to not having a clue or no knowledge it was in relation to knowledge required (basic physics you suggest) to correctly answer Snapes question. I have great knowledge in other areas.

    I did not say or imply I have more knowledge than you. I only suggested you also dont have the knowledge to answer Snapes question.

    As for me learning physics and correcting you if you err. So far you havent stated any physics in relation to Snapes question.

    As for you suggesting I choose to be insulted and that I feel insulted. I dont feel insulted. Never said I was. My initial comment was about you offering an insult to someone. Whether they actually felt insulted or not is not relevant to my saying its bad manners to offer an insult instead of answering the question.

    Hope this clears up things.

    • Amazed says:

      You say you did not imply you had more knowledge than me. You only “suggested” that I share your lack of knowledge. How would you know? Are you claiming that I am just as ignorant as yourself?

      As to insults, you are being a little precious, aren’t you? How do you determine what is insulting if you are not aware of it? As to bad manners, who determines what is mannerly? You?

      Maybe you could take a good hard look at yourself. Are you setting yourself up as the defender of dills that choose to feel insulted? Call the politeness police if you are not happy. I’ll ignore them too! Have you managed to find the scientific “theory” of global warming, or climate change, or something?

      Sorry, I know you admitted you are clueless. I do not mean to taunt a disadvantaged person. My apologies.

  18. Snape says:


    Thanks for tying to defend me, but I should tell you – Amazed has been insulting people on this blog for several years, originally using the name Mike Flynn.

    He was apparently banned by Dr. Spencer (second hand information), but has since come back under various monikers, this being the latest. Sort of like a mosquito you cant seem to swat.

  19. Snape says:


    Those are my thoughts exactly!

  20. Henry Pool says:

    Dear Roy
    Thanks for the informative update.
    as a hobbyist, I have done an investigation into the CO2 warming thing, looking at it from a completely different angle, here!At1HSpspVHO9pwx0EPc_q0yoFNKR?e=kE8DTl

    I know you are pretty much the big expert on this…. If ever you have some time or do get some time, would you perhaps have a look at it, and let me know what you think of it.

    I would very much appreciate any comment you can make.

    You can click on my name for contact details.

    Many thanks!

  21. Monte Olsen says:

    Troll. Ignore the guy.

  22. Another Joe says:

    Let me get this right:

    an event that happened on the SH is supposed to create a global signal, and it ” cannot be as clearly seen in regional averages (e.g. tropics or Southern Hemisphere) … Thus, global averages show the best signal of something new going on, even if that something new is only occurring in a specific region.”

    Could you show the curve for the SH and NH separately? Or does this potentially and visibly impact on the validity of this theory?

  23. Test says:


    Like many ‘skeptic’s in this blog (quotes needed), some newcomers in this endless Moon discussion seem to put toy-like explanations (chalk, coins, racehorses, coffee cups) ahead of any scientific results, even those resulting from century-long observation and research.

    Many ‘skeptic’s doubt about the accuracy of Einstein’s work, explaining that ‘everything made up by Einstein’ can be explained using Newton’s laws.

    But suprisingly, when it comes to Moon’s rotation about its axis, Sir Isaac Newton’s wordings about it suddenly are subject to heavy discredit! How interesting.

    Yes yes, ‘even a genius like Sir Isaac can go wrong’, the ‘skeptic’s say… It is as simple as that!

    Newton’s Propositio (he lacked the time to bake that stuff into a final theoretical work) can be found in his original Latin edition of Principia Scientifica of 1687 (propositio XVII, Theorema XV):

    or in the latest, 1726 edition of his magistral work:

    Here is a translation into English of Newton’s latest Latin Principia edition by Andrew Motte (1696-1734), published in 1729, and out of which the first official American edition was derived in 1846.

    It can be found in

    That the diurnal motions of the planets are uniform, and that the libration of the moon arises from its diurnal motion.

    The Proposition is proved from the first Law of Motion, and Cor. 22, Prop. LXVI, Book I.
    Jupiter, with respect to the fixed stars, revolves in 9h.56′; Mars in 24h.39′; Venus in about 23h.; the Earth in 23h.56′; the Sun in 25½ days, and the moon in 27 days, 7 hours, 43′.
    These things appear by the Phænomena.
    The spots in the sun's body return to the same situation on the sun's disk, with respect to the earth, in 27½ days; and therefore with respect to the fixed stars the sun revolves in about 25½ days.
    But because the lunar day, arising from its uniform revolution about its axis, is menstrual, that is, equal to the time of its periodic revolution in its orb, therefore the same face of the moon will be always nearly turned to the upper focus of its orb; but, as the situation of that focus requires, will deviate a little to one side and to the other from the earth in the lower focus; and this is the libration in longitude; for the libration in latitude arises from the moon's latitude, and the inclination of its axis to the plane of the ecliptic.
    This theory of the libration of the moon, Mr. N. Mercator in his Astronomy, published at the beginning of the year 1676, explained more fully out of the letters I sent him.
    The utmost satellite of Saturn seems to revolve about its axis with a motion like this of the moon, respecting Saturn continually with the same face; for in its revolution round Saturn, as often as it comes to the eastern part of its orbit, it is scarcely visible, and generally quite disappears; which is like to be occasioned by some spots in that part of its body, which is then turned towards the earth, as M. Cassini has observed.
    So also the utmost satellite of Jupiter seems to revolve about its axis with a like motion, because in that part of its body which is turned from Jupiter it has a spot, which always appears as if it were in Jupiter's own body, whenever the satellite passes between Jupiter and our eye.

    { A possibly useful explanation: in astronomy, the upper focus of an elliptic orbit is where the orbited celestial body is located (the lower focus of course is always empty). }

    Later, scientists like Lagrange and Laplace continued Newton’s work with theories he couldn’t provide for, and confirmed the point that Moon’s libration is a consequence of its very slow roation speed.

    I won’t contribute to this imho fully inadequate, meaningless toy-based discussion, and I’m wondering why people like Norman, Ball4, bgdwx and others manage to step into this trap again and again.
    Nor would I ever been willing to accept pseudo-arguments like
    The Moon rotates about the Earth-Moon barycentre
    This is nothing else than stupid, pseudoskeptic blah blah: this barycentre (which some highly educated ‘skeptic’s incredibly suppose to be in the middle of a line between Moon and Earth) is in fact within Earth, at 4000 km distance from Earth’s centre.

    No celestial body ‘rotates’ about a point located within the body it orbits on an ellipse!

    J.-P. Dehottay

  24. Test says:

    It is really amazing to see half a dozen of persons writing here their trivial, stubborn, endlessly repeated stuff as if it was the worldwide most important, most scientific contribution anybody has ever written since the Antiquity.

    I don’t care about them, and continue my references to real science, this time out of the English translation of a Russian document:

    Rizvanov / Rakhimov

    History of development of selenodesy and dynamics of the Moon in Kazan

    In section 3 of the document, we read:

    3. Theory of rotation of the Moon

    The most significant theoretical investigation of rotation of the Moon is undoubtedly the work of Sh. T. Habibullin “The Nonlinear theory LPhL [my emphasis: Lunar Physical librations] of the Moon” [13].

    The author solved the problem of nonlinear fluctuations of rotation of the Moon by methods of N. Њ. Љrylov, N. N. Bogoljubov and N. G. Malkin.

    The nonlinear theory in case of a resonance (f=0.622) gives the steady solution in contrast to the linear theory.

    In the intervals which are far from the resonance, the nonlinear theory does not reveal essential refinements in comparison with the linear theory, but more authentically describes so called “free libration”.

    Sh. T. Habibullin [15] gave the analysis of systems of the selenographic coordinates and developed the theory of precession and nutation of the axis of rotation of the Moon.

    It makes here few sense to reply absolutely stoopid nonsense like

    – ” the authors confound rotation about an axis and rotation about an orbited planet”

    – “the authors aren’t engineers and hence lack to necessary understand of Physics”.

    The so-called, self-named ‘engineers’ should give a proof of their real experience in the engineering field instead.

    Until now, all of them utterly failed in doing that.

    I suspect that none of them has ever worked in that field, and that all of them therefore will comfortably keep behind nicknames or pseudoreal names,like e.g. ‘Gordon Robertson’.


    Do not confound the historically known ‘optical librations’ with the ‘physical librations’.

    While the former are illusions created by the conjunction of several concurring phenomena:

    – the ellipticity of all orbits,
    – the inclination of a body’s rotation axis wrt its orbit plane,
    – the inclination of orbiting planes wrt the planes of the orbited bodies

    the latter are real and are subdivided into two classes:
    – ‘forced’, i.e. generated by constant, commensurable origins
    – ‘free’, i.e. of unknown origin.

    Only the former could be computed by differential motion equations long time before it was possible to observe them.

    I don’t know exactly why it is so important to get knowledge about physical librations. I suppose that this is due to geologists who are interested in knowing more about the satellites’ ‘inner life’, in our case: that of the Moon.

    Pseudoregards from a real, retired engineer to all anonymous ‘pseudoengineers’ posting their stoopid nonsense on this respectable blog!

    J.-P. Dehottay

Leave a Reply to Monte Olsen