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1. MA Rodger at 22:44 PM on 16 August 2026
   CO2 effect is saturated
   

   foxydoxy @885,888,890,

   (1) Treating the atmosphere as an "isolated system" is missing the most basic measure of the workings of the GH-Effect. The T_surface defines the atmospheric temperaure at ground level. The other variable which defines the size/power of the GH-Effect is the 'wavelength T_toa', the atmospheric temperature at the altitude from which the IR of that wavelength is emitted into space. The averaged 'wavelength Tt_oa' will provide the diminished IR cooling which will equal solar heating (under equilibrium). So that 'average' can be calculated from the solar input (since 2000 = +340.2Wm^-2 adjusted for albedo -99.8Wm^-2) = 241.4Wm^-2, this blackbody radiation yielding 255.4K. And over the same period T_surface = 288K. Thus the effective GH-Effect = 32.6K (but lacking a bit in equilibruim)

   This is a good starting-point for the physics of the GH-Effect.

   (2) The path length of IR within the atmosphere is not a good start point for the physics of the GH-Effect. The path length of 15 micorn IR in the lower atmosphere is short (2m, 10m) but that does not hold for the full 15 micron 'band' which has longer path lengths at wavelengths towards the edges of the 'band'.
   And if all the ground-emitted IR is extinguished at some elevation (be it great or small), the GHGs responsible for absorbing that IR will also (almost always because of excitation into a v2 state through collision rather than IR absorption) be also emitting said IR at the same intensity as it absorbs it.
   As the atmosphere cools with altitude in the troposphere, this 'boiling' cloud of IR will diminish in intensity with height. And as pressure drops and the air thins, the path length of that diminished IR will increase. Eventually, the atmosphere thins enough to allow emissions into space. It is the temperature at that point for that wavelength ('wavelength T_toa) that contributes to thr GH-Effect.
   No need to consider the path length other than the point when it stretches out to infinity and beyond.

   (3) The conservation of energy thing is pretty-much taken care of. The IR from the surface is matched by the IR generated from collision in the atmosphere. Likewise a packet of air will be shooting IR up, down and sideways, all this emitting enrgy. But this IR with its Energy_out will be matched by IR from surrounding packets of air and thus the Energy_in. Energy-wise, all is in balance IR-wise. And because the cooling of the atmosphere is pretty constant through the troposphere, tiny difference between the emitted IR_down and absorbed IR_up is matched by the emitted IR_up and absorbed IR_down. (For the pedants, the diminishing IR with altitude results in an upward energy flux which is tiny, about 100x the effect of conduction which is itself famously very very tiny for air. There is also a very very tiny amount of cooling with altitude due to the increasing path length of the IR with a constant lapse rate, a cooling which suddenly will rise to significance as the emissions altitude is reached and the emitted IR_up is lost to space.)

2. foxydoxy at 22:28 PM on 16 August 2026
   CO2 effect is saturated
   

   Eclectic @890

   Who's trying to disprove the important role of CO₂ in our planet's greenhouse effect?  I just want to see it evaluated correctly, and "rebuttals" to CO₂ band saturation that use violations of energy conservation (such as elastic collisions of a CO₂ molecule with an N₂ or O₂ that kicks the CO₂ molecule into the energized state) not helping.  I want valid, not necessarily mainstream, reasons as to why I am urged to watch my "carbon footprint".

   Moderator Response:

   It has been evaluated correctly. The catch is that you can't see it, because your mind is under the influence of Morton's Demon and you are blocking the correct evaluation and substituting an alternate reality of  your own making.

   Your arguments are strongly resembling those of user CallItAsItIs, who polluted this thread nearly two years ago, starting with comment 722. That user had also been active under other names in the past, with the same misinterpretations of how and when energy is conserved, what isolated systems were.

   I strongly suspect that you are yet another incarnation of those previous users. If you are not, you really need to go back to that point, read the comments, recognize that what you are saying has been said previously (and rebutted previously) before commenting again.

   If you are that previous user, you are violating the Comments Policy section against using multiple identities.

3. Eclectic at 21:08 PM on 16 August 2026
   CO2 effect is saturated
   

   Foxydoxy @890 :

   Nevertheless, your "arguments" about absorption / collisions / emissions are not in dispute, surely !

   But you fail to make any argument which disproves the important role of CO2 in our planet's GreenHouse Effect.  Yes, there are other atmospheric factors which contribute to our GH Effect, yet CO2 is one of the major factors.

   That the atmospheric CO2 concentration does produce such an important GHE / climate role ~ is demonstated both by the abstract physics and by the observed (by proxy) evidence of climate changes occurring during past geologic ages.

   Foxydoxy, there is no serious dispute among scientists about the major role of CO2 in GHE and in climate.

   But if you yourself are the new Galileo or new Einstein who has discovered an entirely revolutionary new insight into atmospheric physics ~ then please enlighten everyone immediately.  But thus far you have presented nothing in that direction.

4. foxydoxy at 19:59 PM on 16 August 2026
   CO2 effect is saturated
   

   Eclectic @889

   You are correct that each layer does not conserve energy, but interactions such as absorption, emission, and collisions certainly do; and that is the basis for my arguments.  The only times I have used the word "layer" in my comments is when I am describing the region at the bottom of the atmosphere where 15 micron photons can be absorbed by CO₂ molecules for greenhouse warming.

   Moderator Response:

   To quote Yoda: and that is why you fail.

   You keep picking one small part of the interactions, and acting as if that is isolated from all other parts.

   Your layer at the bottom of the atmosphere is not an isolated system.

5. Eclectic at 19:05 PM on 16 August 2026
   CO2 effect is saturated
   

   Foxydoxy @888 :

   You seem to be confusing yourself.

   Whether an absorption layer is 1 meter deep, or 10 meters deep, or 100 meters deep ~ the layer can absorb "new" energy by several mechanisms  i.e.  by absorption of short-wave solar radiation (directly by dust particles ~ or indirectly per solar heating of the planetary surface and subsequent radiational or H2O-phase-shift transfers or kinetic or convectional transfers from lower or higher layers).

   Each layer does not "conserve" energy, but undergoes a continual flow of energy ~ and shows a diurnal change plus longer/shorter-term changes of energy from advection, or from convection, or from H2O-phase-shifts (which in themselves lead to or precipitate [pun intended]  more changes in in temperature and/or convection in various regions of that layer).

   There is no steady state for any layers ~ but all is in a state of flux (of course, within certain limits that we observe in seasonal / climatic / altitudinal changes).

   Atmospheric layers do not have "conservation" ~ unless your are using  "conservation" in a peculiar  semantic manner that sabotages plain-English communication.  Indeed, perhaps that is where your difficulty may originate.

6. foxydoxy at 15:11 PM on 16 August 2026
   CO2 effect is saturated
   

   Eclectic @885

   You are correct in that CO₂ molecules within the 10 meter absorption layer get thermally excited by collisions with neighboring N₂ and O₂ molecule, but energy is conserved in doing so.  This means that for a collision of a CO₂ molecule with another molecule (usually N₂ or O₂) to kick the CO₂ molecule into the energized state, the combined kinetic energy of the two molecules must decrease by the amount equal to the difference in energy between the excited and original states of the CO₂ molecule.  If this newly energized CO₂ molecule then releases a "new" 15 micron photon, and this photon is subsequently absorbed and converted into thermal energy, then this "new" thermal energy, together with the original loss in thermal energy (to excite the CO₂ molecule), will result in a net-sum-zero increase in atmospheric thermal energy.  

   Therefore, the only way that thermal energy for CO₂ greenhouse warming can enter the atmosphere is by absorption of 15 micron IR radiation within 10 meters of the surfacr.

   Moderator Response:

   Alas, you have rapidly reached the point where moderation is needed.

   You appear to have a great deal of confusion regarding "conservation of energy" and "isolated system". This also goes along with your confusion between what happens at a molecular level and what happens to a large collection of molecules. You can't keep grabbing the properties of one and then apply them as if they are properties of the other.

    

7. Bob Loblaw at 22:57 PM on 15 August 2026
   CO2 effect is saturated
   

   foxydoxy @ 885:

   I think the first thing we need to establish is that you make one horribly big mistake in the second sentence of  your second paragraph. The atmosphere is not an isolated system. Everything that you say that follows from that is nonsensical. The atmosphere receives thermal energy and latent heat and IR radiation from the surface. It receives radiation from the sun. It emits IR radiation to space. It is not remotely close to an isolated system.

   The argument you are starting to present looks a lot like an argument that has been made here before, by multiple accounts. But, unfortunately, not by multiple people, as one individual keeps creating new accounts to try to repeat his bogus arguments. Creating multiple accounts this way is breaking the rules of the Comments Policy. Rules you agreed to when you signed up.

   I strongly suggest that you look through the comments here, to see where your argument has been presented before, and where people have pointed out the errors in that argument. Unless you actually have something new to say, you are wasting everyone's time by repeating the same errors.

8. Eclectic at 22:24 PM on 15 August 2026
   CO2 effect is saturated
   

   Foxydoxy @885 :

   It is not at all clear to me why you are stymied by the "10 meter extinction altitude"  of the 15-micron photons emitted by the Earth's surface.

   CO2 molecules within that 10 meter altitude band get thermally excited by collisions with neighboring N2 and O2 molecules, and then can re-emit (frequently!!) 15-micron photons in all directions.  Some of this "new" radiation will transmit upwards into the next 10-meter layer adjacent above.

   Likewise, that higher layer will radiate into the next 10-meter above that one . . . until eventually at high altitudes the air density is so low that the molecular spacing is great enough to allow some of the emitted 15-micron photons to escape the planetary atmosphere and be lost (and thus be part of the Earth's radiational spectrum lost to space).

   Thus "saturation" is a rather misleading concept ~ and the real interest is the heat gradient in the layers of atmosphere (i.e.  the actual Greenhouse Effect that contributes to the planetary surface temperature).

   Of course, that important temperature gradient is also influenced by convection and H2O condensation and solar radiation absorption by dust particles etcetera.  (The solar 15-micron emissions are rather small in this overall scheme of things.)   In the grand picture, the CO2 radiations are nevertheless a very important contribution to surface climate.

9. foxydoxy at 14:30 PM on 15 August 2026
   CO2 effect is saturated
   

    

   Bob Loblaw,

   I thought it might be beneficial to both of us, and of course anyone else taking an interest in this CO₂ band saturation effect, to briefly summarize my understanding of what's happening with this 15 micron band which essentially defines CO₂ greenhouse warming. Please point out any misunderstandings you feel I may have.

   First, we understand that we are trying to assess warming of the entire atmosphere due to CO₂ absorption of IR radiation in the specified 15 micron band. This means we regard the atmosphere as an isolated system and identify all sources of 15 micron radiation entering it. At this point, understand that while CO₂ absorbs and emits such radiation, it is not a source. Carbon dioxide molecules can only temporarily absorb and relay this radiation. The only source of 15 micron radiation (and in fact all atmospheric IR radiation) is the surface of the earth. Now, from measurements of CO₂ absorption coefficients in the laboratory and the atmospheric concentration of CO₂ near the surface of the earth, we find the extinction altitude of this 15 micron radiation to be about 10 meters. This means that, for all practical purposes, the entire band is absorbed within a 10 meter layer at the surface. The energized CO₂ molecules from this absorption band then collide with N₂ and O₂ molecules which cause them to drop back to their original energy states. The stored energy released in the process then takes the form of increased total kinetic energy of the molecules involved in the collisions. This we identify as heat or thermal energy which causes the observed warming. At this point, it is the rules of conduction, convection, and other forms of heat transfer that decide where this heat goes and what it warms. I believe you have lots of codes and models for handling such problems.  These mechanisms cannot, however, introduce more heat without a clearly identified source of energy for that heat. To do so would violate energy conservation, and at this point, we have accounted for all warming arising from the CO₂ greenhouse effect.

   Let us now consider the implications of the 10 meter extinction altitude mentioned earlier. In this case, all radiation within the 15 micron band is absorbed and converted into thermal energy well within the atmosphere. This means that increasing the concentration of CO₂ will not result in any further absorption or warming. The supply of 15 micron photons (the source of CO₂ greenhouse warming) has already been depleted by the CO₂ currently present. This is what is generally called CO₂ band-saturation, and it raises serious questions as to whether our "carbon footprints" have anything to do with global warming.

    

10. Bob Loblaw at 05:15 AM on 15 August 2026
    CO2 effect is saturated
    

    foxydoxy @ 883:

    There is a lot of room between individual molecule behaviour and "the entire atmosphere". I'm afraid I'm not really sure where in that vast range you are placing "macroscopic scale".

    The absorption and emission of IR, transfer of energy by collisions, etc. is happening at the molecular level. The concept of temperature is not, so you can't talk about molecules cooling or warming. You need to look at a bunch of molecules for that - a big bunch.

    Fortunately, you don't need to go to "the entire atmosphere" to get a bunch of molecules, though - and climate science doesn't. One m³ of air weighs over 1kg, so if you figure out how many moles that is, you can use Avogadro's constant (6.022x10²³) to figure out just how many molecules that is. (It's a bunch.)

    So, macroscale discussion of these effects can be carried out for pretty small volumes of air. Climate models do not go down to the 1m³ level - but they do divide the vertical profile into a number of layers, and divide the horizontal world into a number of areas. Each box then becomes a unit for conservation of energy, total absorption, total emission, temperature, etc. Mass and energy can move from box to box, and radiation can be absorbed, emitted, or pass through (no interaction) in each box.

    I know you will not have been able to wade through the 878 comments that came before you, but in comment 805 I discussed some of the characteristics of a one-dimensional (vertical) climate model and present a few graphics. This figure in that comment shows the results of a model as it progresses through (modelled) time to approach equilibrium. Dependent on the starting conditions, at each time step the model will warm or cool layers in response to the energy changes in that layer. (The figure is from Manabe and Strickler 1964.)

    

    I also suggest that you look through a blog post I did a few years ago on Beer's Law, which covers some of the theoretical aspects of radiation transfer in the atmosphere. The comments provide very useful additional information.

    The collisions between molecules are elastic in the sense you describe. There is no loss of energy. As MA Rodger pointed out, any molecule that has absorbed energy by absorbing IR radiation will almost always lose that energy to other molecules via collision, not the emission of radiation. That also holds true for any molecules gaining energy via collision with another molecule. If their energy level becomes higher than other molecules they collide with, they will lose energy via the next collision.

    Who gains, who loses depends on the relative energy levels of the two molecules. Sometimes, a molecule will lose energy by emitting radiation, but nearly all the energy movement within the volume of air is by collision. That's why the concept of temperature (average kinetic energy of a bunch of molecules) works. Keep in mind that nearly all the other molecules that a CO2 molecule will run into are either nitrogen or oxygen. Collisions are an equal-opportunity energy transfer mechanism.

    A more technical discussion (linked elsewhere in this stream, but repeated here) is over at Eli Rabett's blog.

    Note that this discussion is getting a rather long way away from the topic of the OP - the myth that the CO2 effect has reached saturation.

11. foxydoxy at 11:19 AM on 14 August 2026
    CO2 effect is saturated
    

    I guess when I said "cooling" in 881, I meant only the loss of combined kinetic energy a CO₂ molecule and another molecule colliding with it (usually N₂ or O₂) where the collision causes the transition of the CO₂ molecule to the higher energy state from which it can emit a 15 micron photon.  I did not mean cooling of the entire atmosphere. 

    Since we are talking about collisions, however, there is one point of confusion that I believe may be troubling many individuals.  That is, when they hear or read the word collisions, they immediately think elastic collisions where there is no loss of total kinetic energy among the colliding particles.  This, of course, would be a clear violation of energy conservation if the collision involved an energy transition of one of the colliding particles.

12. Bob Loblaw at 07:43 AM on 14 August 2026
    CO2 effect is saturated
    

    foxydoxy @ 881:

    You are incorrect when you state "On the macroscopic scale, this would imply cooling." It only implies cooling if there are no other sources of energy of equal magnitude coming into that layer.

    Although you speak of the transfers of energy via convection, and speak of it redistributing energy, you neglect that this transfer of energy can counteract the loss of energy as radiation is emitted. The one molecule that loses energy via collision will re-gain energy from collision with higher-energy molecules, and the bulk properties will regain energy via these other energy transfers. Convection will bring in higher-energy molecules.

    Have you every heard of "radiation fog"? This occurs at night, close to the surface, when temperature inversions (cooler closer to the ground) suppress convection to the point that there is very little vertical mixing of the air. As a result, you do see the "macroscopic scale cooling" that you refer to. In this case, its the surface IR radiation being lost that removes energy (sends it upward), and that cooling surface cools the air by contact, but it is a case of radiative cooling. The air can't mix, so it can't bring energy to the surface to keep it warm.

    But under normal atmospheric mixing, the vertical energy transfer via convection has no difficulty in counteracting the energy loss by emission of IR radiation. You don't see radiation fog on windy nights - lots of vertical mixing. You need very calm conditions (and typically clear skies, which reduces any incoming IR radiation at the surface).

    Climate models do conserve energy. They do account for loss by IR radiation, but they also account for gains from absorbed radiation, transfers by convection, etc. If convection or radiation absorption can't keep up with IR losses, the models will cool that layer - but there won't be some infinite cooling trend just because there is IR radiation loss. Layers will warm when convection and radiation absorption exceed IR losses. It is not a one-way street.

    A key thing to remember is that convection involves both upward and downward movement of air. In equal quantities. It can carry energy upwards or downwards. If a puff of air moving up is warmer than the air above it, this will mean that the replacement air from above will be cooler, and it's this "warm up, cool down" that results in a net upward transfer of energy. In a temperature inversion (warm air over cold), convection will be moving thermal energy downwards. In either case, that layer in the middle that is emitting IR radiation will be getting thermal energy brought in - either from above or below, depending on the temperature profile.

13. foxydoxy at 05:38 AM on 14 August 2026
    CO2 effect is saturated
    

    MA Rodger @ 880

    Thanks for your diagram of absorption coefficient vs. wavelength.  It is of higher resolution than the plots I remember seeing, and those weaker sidebands do have somewhat higher extinction altitudes.  In my comment @879, I focused primarily on IR absorption and conversion to thermal energy via collisions which are the fundamental mechanisms by which greenhouse warming occurs.  There were several other important points I wanted to get to, but felt my comment was getting too long as it was.

    You are correct about CO₂ molecules becoming energized through collisions as well as IR absorption, but energy must be conserved in the process.  This means that the colliding molecules must lose some kinetic energy in order to provide the CO₂ molecule with the energy it needs for the transition.  On the macroscopic scale, this would imply cooling.

    Also, many critics of the CO₂ band saturation theory correctly point out that if all of the thermal energy from the 15 micron band were packed into a 10 meter thick layer at the surface, then we would have one scalding surface!  What mitigates this effect, however, is convection.  As the surface warms, steep temperature and pressure gradiants form just above the surface which cause updrafts.  These updrafts then carry the excessive thermal energy upward which results in a more uniform distribution of such energy over all altitudes. Note that this convection process does not affect the total amount of thermal energy in the atmosphere. It merely redistributes what energy is already there.

14. MA Rodger at 02:07 AM on 14 August 2026
    CO2 effect is saturated
    

    foxydoxy @879,

    It is correct that an IR photon of 15 micron will not get far in the lower atmosphere. 10 metres? On average? I thought it was less.

    And it is correct that the vast majority of those absorptions will result in the energy being transferred to the air as heat following collision. Collisions happen very quickly (milliseconds) while the relaxation time for an excited CO2 molecule takes longer (tenths of a second), on average.

    (One point to add is that the CO2 does have less strong absorption bands very close-by 15 microns and thus the almost-15-micron IR which can be absorbed bt CO2 will have a far longer path-length. It is only the central part of the 15 micron wave band that is absorbed so quickly.)

    Your description leaves out the mass of CO2 molecules that become excited without absorbing IR but by the frequent collisions with other molecules. Due to the massive number of collisions, at any one time, there are far far more excited CO2 molecules due to collision than are due to IR absorption. And the physics says that this excited population will emit IR commencerate with its temperature. If the air is the same temperature as the surface, the returning IR will match the surface IR. Also, the surface only has a top (this side of the planet). The air has a top and bottom so it will also emit IR up as well as down, and at the same intensity.

    Crutially, thus is all about temperature. The IR flying round the atmosphere will reduce in intensity as the air cools with height (due to the falling pressure). So when the IR reaches the TOA, there is less of it shooting out into space, less of it cooling the planet.

    Thus the greenhouse effect.

15. foxydoxy at 21:05 PM on 13 August 2026
    CO2 effect is saturated
    

    In the At-a-Glance section of this page, it is stated that

    You cannot say, “CO₂ is saturated because the surface-emitted IR is rapidly absorbed”, because you need to take into account the whole atmosphere and its constant, ongoing energy-exchange processes.

    In taking into account the whole atmosphere, however, we must remember that except for the earth surface and the TOA, it is an isolated system. As such, energy can only enter or leave the atmosphere through one of these surfaces, and thermal energy enters primarily from the earth surface. This energy arises from the radiant spectrum of the earth in thermal equilibrium with the sun, and is mostly in the infrared range. In 1824, Jean Baptiste Fourier made an estimate of the earth's surface temperature using known astrodynamic quantities and assuming a planetary object (ie.blackbody) model of the earth. This model had previously been shown to work well for the moon and planets without atmospheres. His calculated temperatures, however, were substantially lower than those obtained from the surface-level thermometers. From this, he concluded that the atmosphere was somehow acting as an insulating blanket retaining some additional heat that would otherwise be radiated into space. Later on, in the 20^th century, this would be called the greenhouse effect.

    This greenhouse effect arises from the presence of certain (at least triatomic) trace gases with absorption bands occurring in the infrared (IR) spectral range. These gases then absorb upwelling IR radiation from the surface of the earth (within their respective absorption bands), thereby placing a portion of their molecules into higher energy states. Eventually, these energized molecules collide with other molecules (including O₂ and N₂), causing them to release this extra energy and return to their original states. In the process, this released energy then takes the form of increased combined kinetic energy of the two colliding molecules. This, we recognize as heat or thermal energy which causes a temperature increase.

    In regard to the CO₂ greenhouse effect, the primary absorption band is a strongly absorbing but relatively narrow band with a wavelength around 15 microns. There are also two other minor absorption bands, but they only affect the total absorption by a few percent and are generally neglected in CO₂ greenhouse studies. As acknowledged by all experts in spectroscopy, the CO₂ absorption of this band is strong enough to give it an extinction length of about 10 meters. This means that nearly all (99%+) of the 15 micron radiation eminating from the surface of the earth is absorbed below 10 meters. Most but not all of this energy is converted into thermal energy as described above. For our purposes, however, we will assume that all absorbed 15 micron radiation becomes thermal energy since this would result in the largest possible temperature increase.

    At this point, it must be indicated that 15 micron photons absorbed above the 10 meter altitude would not result in any more warming since these photons could not have originated from the influx of new photons (and new energy) at the surface. A 15 micron photon above the 10 meter extinction altitude could only have been emitted by an already energized CO₂ molecule well inside the atmosphere. Absorption of this photon by another CO₂ molecule would only result in a zero net-sum-gain in electromagnetic energy and no net changes in the atmosphere.

    Statements that CO₂ is always emitting and absorbing IR radiation at all levels of the atmosphere at all times are correct, but energy must be conserved in the process.  In the case of atmospheric warming, the energy driving that warming can enter only from the surface. Therefore, photons transporting this new energy must originate from the surface and not from mid-air CO₂ molecules. They can act only as energy relays, not energy sources.

16. sparky at 00:31 AM on 12 August 2026
    The Strongest El Niño Ever
    

    Your opening sentence notwithstanding, I found your analysis troublingly unmeasured.  You mention RONI only briefly and then return to using ONI.  Certainly NOAA is now fully embracing RONI as a more appropriate metric, not some experimental metric that should be mentioned only in passing. Second, if you look at the CPC web site, they show adjusted forecasts that account for the statistical bias in their model when compared with past observed ENSO behavior.  These adjusted forecasts are significantly lower in the peak RONI predicted for this event than the unadjusted forecasts you show.  Please see https://www.cpc.ncep.noaa.gov/products/CFSv2/cfsv2fcst/CFSv2SST8210.html  The current forecast is for a peak RONI of around 2.3 deg. C.  Yes, definitely a big event, in league with the handful of historically largest events on record, but not precedent shattering as your article implies.

17. Bob Loblaw at 23:32 PM on 10 August 2026
    2026 SkS Weekly Climate Change & Global Warming News Roundup #32
    

    RedRoseAndy:

    You need to be more specific when referring to "turbine generators". Hydroelectric dams use turbines, driven by water. Generators using natural gas are typically turbines. Wind power uses turbines. Steam generators (powered by nuclear, coal, or others) use turbines. A turbine is something that produces electricity by spinning, and many technologies use a variety of methods of making a turbine spin.

    Which article in this OP prompted your comment? The one titled "Factcheck: How nuclear, gas, wind and solar power are affected during heatwaves" covers a variety of power sources and how heat affects their efficiency. Hot spells are often associated with low winds, so wind power production drops - but solar production is high, so wind and solar work well together. Some technologies run into efficiency problems simply because of heat, whereas other suffer from lack of cooling efficiency (often due to lack of water, or warmer water).

    ...and providing sources for your numbers would help.

18. RedRoseAndy at 21:17 PM on 10 August 2026
    2026 SkS Weekly Climate Change & Global Warming News Roundup #32
    

    The UK uses half of it's fresh water in turbine generators. We can shut fifty of them just by rebuilding all old onshore wind turbines to planning permission maximums. This would triple the electricity generated by them. Octopus Energy are rebuilding 10% of our onshore wind turbines, Germany are doing all of them.

19. prove we are smart at 12:51 PM on 7 August 2026
    Skeptical Science New Research for Week #32 2026
    

    This article from above- 

    Managing climate overshoot: a risk-based strategy for climate stabilisation, Taylor et al., Frontiers in Climate

    Outlines the reality we are all living in and more hopium to offset my increasing doomism.

20. prove we are smart at 17:22 PM on 30 July 2026
    The government canceled this nature study. Scientists finished it anyway.
    

    In hindsight, the Australian recession in early 1990s forced me to leave my 20 yr tradie job and reinvent myself to become a farmer. Now retired after 30+ yrs, it was a poorer paying job but richer in what matters to your well-being. 

    Having nature time is a positive but critical thinking is essential too because it helps you distinguish signal from noise, truth from manipulation, and insight from assumption. It’s the skill that lets you navigate complexity rather than be overwhelmed by it. If nature time helps people rediscover their quiet thoughfulness-lets hope it is part of a catalyst for a needed change worldwide.

21. jozef.van.giel@gmail.com at 05:24 AM on 30 July 2026
    Fact brief - Do solar plants require backup from fossil fuels?
    

    Alone, Batteries are unaccaptably expensive for seasonal storage. Despite that fact I agree with the statemen. You can backup with nuclear energy.

22. Bob Loblaw at 05:43 AM on 29 July 2026
    Hot days, cold thermometers
    

    This is an interesting read about the pitfalls of "raw" data and poor data analysis.

    Any scientific paper is supposed to outline the sources of data, the analysis done ("methodology"), the possible interpretations of that data and analysis (including interpretations that may go against the hypothesized explanation) - all prior to drawing conclusions.

    The data sources used and the methodology applied to transform that data are dependent on the question that is being asked. Proper methodology will extract the signal from the noise, and reveal the patterns buried in the avalanche of information. Improper methodology will create biases that hide information.

    The simple example is to sample a sine wave at intervals of 2π, get values of 0,0,0,0,0..., and decide that the signal is not varying. Or decide that the signal may be varying, but decide that you want a simple average over time, so you average over 2π intervals, and decide it's safe to stick your finger in that light socket that the "experts" said has 120V running through it.

    Recent SkS discussions have touched upon this "raw data" issue. People saying "here is a link to data that proves my case - figure it out". Or people citing sources that they call "raw", with the argument that other "processed" data can't be trusted.

    In the case that Zeke has described here, the bad analysis that started the discussion Zeke is casting illumination on it makes several bad assumptions that erroneously treat certain data sources as unbiased representations of reality.

    • The assumption that each temperature station carries equal weight in obtaining a regional average. Adding a bunch of closely-packed stations in a warm region doesn't warm the national average, and closing a bunch in the same region doesn't cause cooling.
    • The assumption that you can pool a bunch of data from areas with different characteristics, and treat the average or total as if it applies everywhere.
    • The person with a raging fever that trudges through a snowstorm to the hospital and arrives with frozen feet is not on average "doing fine".
    • The assumption that using a max/min thermometer reset once a day is not influenced by the time of day it is reset.
    • A max/min thermometer already represents a large degree (pun intended) of data processing. Temperature varies continuously through the day, and representing it my two numbers recorded over the past 24 hours does not give you "raw" data.
    • The use of different measurement technologies (liquid in glass vs. electronic) represents a change in data processing.
    • "Data processing" can be done by mechanical means as well as mathematical means. By its nature, a liquid in glass thermometer averages over a period of time - it takes time for it to heat up or cool down. Electrical sensors can provide extremely rapid response if they are small, or slow response (read "averaging") if they have more mass. This response time needs to be considered in the methodology used to look at the data.
    • Choosing the correct measurement technology is dependent on the question being asked.

    Any time someone claims "I'm right - I used raw data", take it with a large dose of salt.

23. Bob Loblaw at 03:35 AM on 24 July 2026
    Dangerous and historic wildfire smoke pollution event engulfs the U.S. and Canada
    

    wild @ 8:

    I disagree that native populations are well-distributed to manage the boreal forest writ large. The figure from the paper you cited shows vast areas of the boreal forest that are very sparsely covered. (Keeping in mind that locations of reserves, as provided in that paper, are only partly representative of the historic range of the indigenous population.)

    Compare that figure to the following figure, which shows today's fire distribution in Canada, taken from the Canadian Wildland Fire Information System. (I am grabbing today's display as a local file, as the image will change over time.)

    

    Note that many of the fires are in the northern portions of the boreal forest, where there would have been relatively little human activity historically. These areas are often still very difficult for travel.

    The same applies to today's smoke patterns (same source):

    

    Again, the origins of much of the smoke is in sparsely settled areas.

    I would agree that many historical indigenous practices would be of benefit for protecting settled areas, and that our current forestry, building and development habits have made for very difficult times in recent years. But nothing done on local or regional scales surrounding current settlements and forest harvest areas will do much for the large areas that are currently unpopulated and burning.

     

24. wilddouglascounty at 00:23 AM on 24 July 2026
    Dangerous and historic wildfire smoke pollution event engulfs the U.S. and Canada
    

    Bob @ 7:

    Actually I had read Zeke's article from his Climate Brink posts, and I also suggested to him that he read over the article I linked to. The very same figure you linked from that article shows that the native populations were well placed to indeed manage the boreal forests through the use of local, small scale burns that created buffers in much the same way as is being documented in Australian aboriginal fire management practices, most vividly described in Victor Steffensen's excellent book "Fire Country." The goal is not to burn over the entire boreal forest as you suggested in your calculations of hectares/person, but rather to create and mantain a mosaic of burned areas that stimulates biodiversity, breaks up the potential for megafires, protects villages, etc. The nomadic nature of the communities, particularly the seasonal hunting and gathering cycle, is conducive to and consistent with such management practices and there is evidence that such practices covered more land than you might expect. All of this is not to say that the megafire problem exacerbated by climate change is not a huge problem, but as in Australia, the indigenous fire management practices that were practiced for thousands of years, then suppressed, offers an excellent tool for the future in regards to optimizing biodiversity, strengthening the links of human communities to the surrounding boreal forests, and helping mitigate some of the threats of megafires to those communities. Nothing short of reducing our fossil fuel emissions will truly mitigate the mess we're in, but it's a both/and situation that is possible here!

25. Bob Loblaw at 06:00 AM on 23 July 2026
    Canada's boreal wildfires aren't just bad forest management
    

    Tamino has posted a blog article about Canada's forest fires, along with some relevant climate analysis.

    Short version: the increase in forest area burned is statistically significant, and the expected climate variables indicating shifting climate and a longer fire season (increasing temperature, decreasing spring snow cover) are also significant.

26. Bob Loblaw at 04:39 AM on 23 July 2026
    Dangerous and historic wildfire smoke pollution event engulfs the U.S. and Canada
    

    Wild @ 6:

    It may be that you hadn't read Zeke Hausfather's reposted article from today that covers several aspects of the Canadian boreal forest management question in detail. Among other things, he specifically talks about the large areas of Canada's boreal forest that have never seen any form of management.

    Regarding your link to the indigenous forest management practices, I think there is a matter of scale to consider. A quick read of that article gives me the impression that many of the practices they talk about are largely local. These can be highly important in helping protect a settlement and managing local land use, but do not represent a methodology that can be applied to managing the boreal forest writ large.

    Their figure 1 shows the scattering of current indigenous land (reservations) within the boreal forest. In the past, many indigenous cultures were somewhat nomadic, which would increase the likelihood that the use of fire (or mitigation of fire risks) is largely local. The map shows large areas of the boreal forest with little or no indigenous presence today. (The figure cannot be displayed here directly. This link will take you to it, if you don't want to follow wild's link to the entire article.)

    https://link.springer.com/article/10.1007/s40725-022-00168-9/figures/1

    Going back to the 1800s, the indigenous population in those areas was probably of the order of 100,000 (although very hard to estimate, I would guess). This is one source I could find with some actual numbers. (I ignored what Google AI thinks it can intelligently espouse.) As I mentioned above, the boreal forest covers some 550 million hectares. That would be 5500 hectares per individual for the indigenous population to "manage".

27. ubrew12 at 02:55 AM on 23 July 2026
    Canada's boreal wildfires aren't just bad forest management
    

    The U.S. NorthEast also has a lot of pine forests: New York, Maine, Vermont, etc.  Burned acreage per year has decreased there in recent decades, unlike what is happening in the U.S. West.  It seems to me this makes 'forest mismanagement' a less likely explanation for the increased fire damage in the West, as the same management techniques are used in the NorthEast.  What does fit both data points, however, is climate change.  The West is drying out, and much of that precipitation is now falling in the NorthEast.

28. wilddouglascounty at 00:10 AM on 23 July 2026
    Dangerous and historic wildfire smoke pollution event engulfs the U.S. and Canada
    

    The Republican charge that the boreal forests are being mismanaged and the appropriate push back that this is driven by climate change does overlook another important factor for the future: active suppression of cultural fires set by indigenous nations who used to manage these boreal forests much more effectively than they are currently managed. Starting in the 1600s, indigenous fire management of the landscapes in question were actively suppressed across much of the boreal forest region, and yet those fire management traditions are still alive in many of the 600 predominantly indigenous communities across the north woods, who ironically are the most heavily impacted by the current mega-fires. Reflecting a recognition of the importance of aboriginal fire management techniques in Australia, there has been a quiet revolution that has been a long overdue recognition that indigenous burning practices, small in scale and well timed earlier in the year, can head off much of the large scale dangers that are inherent in boreal forests that are not logged or otherwise accessed by western lumber/agricultural interests.

    It is a misnomer to say that these boreal forests were not actively managed just because they weren't being logged. For an excellent research paper outlining these practices and their results on biodiversity, forest composition, wildfire management and human's relationship to these forests, I recommend reading "Centering Indigenous Voices: The Role of Fire in the Boreal Forest of North America" in the journal Fire Science and Management: https://link.springer.com/article/10.1007/s40725-022-00168-9

    Moderator Response:

    [BL] Link activated.

29. prove we are smart at 18:32 PM on 22 July 2026
    Canada's boreal wildfires aren't just bad forest management
    

    Thanks for the facts Zeke. We know a lot about fires too in Australia, and the grand standing politicians muddying the waters. If the diminishing flora and fauna could speak, what shame would be cast on those clever apes.

30. prove we are smart at 13:20 PM on 22 July 2026
    Dangerous and historic wildfire smoke pollution event engulfs the U.S. and Canada
    

    Lets be clear, 25% of the CO2 in the globes atmosphere has been spewed out by one country to last for centuries. This country willingly elects known climate change deniers as their leaders and role models. May the smoke from these new normal fires settle over their land and force the consequences of climate change inaction into their thoughts.

31. Bob Loblaw at 11:30 AM on 22 July 2026
    From the eMail Bag: the Beer-Lambert Law and CO2 Concentrations
    

    a female Faust:

    If you want to try this dye in water experiment described in the OP, I would encourage you to do so. Perhaps, if you want to see what happens with different wavelengths of light, you could try different colours of dye.

    As mentioned in the OP, I used some woodworker's brown dye, simply because I had it available. You could also use many household colouring agents: different soft drinks (cola, orange, grape), tea, coffee, food colouring, artists paints (water colours) and so on. Something like milk would not work - it is a colloidal suspension, not a dissolved compound. You want something that is clear (more or less) once it dissolves but adds colour.

    If you do experiment, I'd encourage you to come back and tell us what you see.

32. Bob Loblaw at 10:56 AM on 22 July 2026
    Dangerous and historic wildfire smoke pollution event engulfs the U.S. and Canada
    

    Michael:

    Yes, much of the forest is unmanaged. Much of it has no road access, and is not harvested. What management happens is managing harvesting and reforestation. The forestry companies that are given the rights to an area will build roads as needed - because they want to be able to take the wood out.

    In British Columbia, historically there have been locations with huge trees where they have used large helicopters for extraction of highly-valuable timber, but that is in coastal forests, not the boreal forest. Much of the boreal forest timber is used for basic dimensional lumber (the proverbial 2x4 for house construction), fence posts, pulp for paper, etc.

    Fire-fighting priorities have changed somewhat over the decades, but much of it is geared towards protecting human habitation, areas of active timber harvesting, etc. They do try to hit small fires early, to prevent large ones from developing. They also try to leave less slash around after harvesting, but again that will only be in the harvest areas.

    In the boreal forest, a lot of the wood is deadwood on the ground, rather than in living trees. That's the natural state, long before anyone could imagine "managing" the forest. The largest carbon storage in the boreal forest is actually in soil carbon.

33. michael sweet at 07:51 AM on 22 July 2026
    Dangerous and historic wildfire smoke pollution event engulfs the U.S. and Canada
    

    Bob Loblaw,

    It is my understanding that the great majority of the Canadian boreal forest is not managed at all, and has not been managed in the past.  The large fires of the last few years, which did not occur in the past, cannot be caused by mismanagement.

    While a lot of forrest in the USA, and Canada, is managed, there are large areas of both that have never been managed.  Increases in fire in unmanaged forest are directly caused by climate change.  The deniers are simply looking for a simple excuse that sounds good, not an actual explanation.

    But you already knew that.  Hopefully it helps other readers.

34. Bob Loblaw at 06:05 AM on 22 July 2026
    Dangerous and historic wildfire smoke pollution event engulfs the U.S. and Canada
    

    Alas, the "you need to manage your forests" deflection point was used in the US a few years ago, when California was suffering from severe fires. The usual suspects were in "climate change can't be a factor"" mode, and looking for any possible alternative explanation - ABC (Anything But Carbon dioxide). It's the standard playbook on climate change contrarianism - look for any other factor, and try to deflect attention towards that squirrel.

    Trump has threatened (and now announced) tariffs as a result of the smoke.

    The Canadian boreal forest covers an area of some 550 million hectares. We have about 41 million people. That averages out to about 13 hectares each. We'd have to get each person cleaning 13 hectares to cover the forest - and much of it is not accessible by roads. I can just imagine the bulk email:

    In order to manage Canada's boreal forest, you have been assigned 13 hectares you need to clean up. It is located 800km from the end of the road in northern Ontario.

    Please make sure you get it cleaned up by Thursday next week.

    The boreal forest is dependent on fire for much of its ecology. Forest management does play a role in fire frequency and intensity, but claiming forest fires will stop with proper management is loony.

35. Bob Loblaw at 05:49 AM on 22 July 2026
    From the eMail Bag: the Beer-Lambert Law and CO2 Concentrations
    

    a female Faust @ 34:

    Three problems with your idea of using CO2 in water:

    1. You need to use a source of radiation that is at a wavelength where CO2 absorbs. That means a non-visible source of radiation (somewhere in the IR band). You will not be able to see the radiation with the human eye - you'd need an appropriate detector.
    2. Liquid water absorbs IR radiation pretty much completely. Adding CO2 will not absorb more, as all relevant IR radiation is already absorbed.
    3. As a near-perfect absorber of IR radiation, liquid water also is a near-perfect emitter of IR radiation. Any IR radiation detected coming from the liquid water will be IR radiation that was emitted by the water, not passing through it.
36. a female Faust at 02:19 AM on 22 July 2026
    From the eMail Bag: the Beer-Lambert Law and CO2 Concentrations
    

    re your experiment: i am curious what you think would result from using CO2 itself, rather than dye, to adulterate the water (and if you think that information interesting, relevant, or useful).  curious enough that i had to sign up to submit this comment...curious enough, in fact, that, especially should that curiosity be shared, i may just have to replicate the experiment with that alteration, that is, using water that is carbonated instead of coloured.

37. prove we are smart at 18:39 PM on 21 July 2026
    Dangerous and historic wildfire smoke pollution event engulfs the U.S. and Canada
    

    Here is another example of the environment affecting the people in a very damaging way. Along with increasing horrific algae blooms, fresh water declines, weather patten anomalies, ad nauseam.

    Many people understand the existential threat the co2 increase in the atmosphere is creating day by day, yet till it affects them meanfully, personally and constantly, this is what most people in the world really worry about, www.gallup.com/analytics/701519/worlds-most-important-problem-report.aspx?utm_source

    We can come together every 4 yrs for sport or to save our ozone layer yet I'm told constantly not to scare people with the truth of an increasingly malevolent weather from our modern industrial practises and lifestyles. 

38. Bob Loblaw at 05:31 AM on 19 July 2026
    Eastern U.S. broils after heat wave kills over 1,300 in Europe
    

    Michael @ 10:

    Thanks for the positive feedback and kind words. I (nearly) always write discussions like this assuming that there are at least a few lurkers that will read my comments and learn from them - something more than just the one person I'm discussing with directly.

    I agree with you about the need for people posting comments to provide some analysis, rather than just posting a link to "data". There is almost no such thing as "raw data" - any measurement has some level of implicit or explicit processing involved. From the recent discussion, I'll take the example of "wind direction". What does "average wind direction" really mean?

    • You can't just take a collection of wind direction readings and do a simple average. One minute of wind from 5° averaged with one minute of wind direction from 355° does not a south wind (180°) make.
    • The usual process is to treat wind as a vector (speed plus direction) and sum the vectors to get the resultant vector. This gives more weight to the readings with greater wind speeds (among other factors).
    • ...but the magnitude of the resultant vector will be less than the mean speed, if there is any variation in direction. Twelve hours of north winds at 40km/hr combined with 12 hours of south winds at 40km/hr does not a calm day make.

    When Eric posted his strong claim ("never") about temperatures and exhaust heat from the terminals, my spidey sense immediately began to think we'd be dealing with another version of Anthony Watt's claims about station siting affecting temperature readings and rendering them useless.

    • My background (people can read a bit about it on the SkS Team page) includes much work in microclimatology, so the immediate question to me was "where exactly is the weather station located?"
    • ...but documentation on airport weather stations often provides the Airport Reference Point (as mentioned in comment 4), not the actual instrument location.
    • ...and I knew to look for this because I have a background in instrumentation and standards for automated weather stations. Aviation stations are linked to aircraft needs (such as altimeter settings) and have their own standards.
    • So Google Earth to the rescue - and because I knew what to look for, I could fairly easily find the actual weather station on the imagery.

    For the record, here is the snippet from Google Earth that shows the automated weather station at Reagan airport:

    

    I immediately recognized the shadow of the anemometer (wind speed and direction, top middle) mast, and the wind shielding around the precipitation gauge (circular pattern on the left). [Again, my experience includes a lot of time working around automated weather stations, so I know what they look like.]

    Later confirmation that I had found the correct location came when Eric posted information about BWI and Dulles airport weather stations. For the record, here are GE images for Dulles and BWI:

    

    

    Note the close similarity in the views. Not exactly the same, but clearly following a similar standard layout. FYI, I was able to find a NOAA image of their standard ASOS (airport weather) system. Looks familiar...

    

    As for working through and combining various sources of data related to the problem at hand (AC exhaust), my background also includes a period of time participating in the Canadian met service's data quality working group. I finished my time with the met service (in part) supervising the staff responsible for data QA/QC.Although automated systems do some checks (detecting spikes, step changes, unrealistic instrument readings, etc), most of these require an examination by human eyeballs. Figuring out "is that reasonable?" requires a blend of detective skills plus an understanding of micro- and meso-scale weather and climate. A sudden drop in temperature makes sense when you see a similar drop a few hours earlier or later in other nearby stations, and the shifting wind patterns and pressure changes tell you a cold front is moving through.

    To Eric's credit, although he started with a strong assertion about exhaust plumes, he clearly listened to what I was saying and showed a willingness to change his mind. In the end, he agreed that AC exhaust plume hypothesis was not plausible. That shows a tendency towards genuine skepticism, not the dogged "you can't change my mind" that is often seen in climate discussions.

    As you state, Michael, there is a level of skill involved. There is also a level of experience and training - "knowledge" as you describe it. Two old quotes come to mind:

    From Alexander Pope, An essay on Criticism:

    A little learning is a dangerous thing;
    drink deep, or taste not the Pierian spring:
    there shallow draughts intoxicate the brain,
    and drinking largely sobers us again.

    And from the Canadian Aviation Safety Letter (from back in my pilot days):

    Learn from the mistakes of others. You won't live long enough to make them all yourself.

     

39. michael sweet at 01:05 AM on 17 July 2026
    Eastern U.S. broils after heat wave kills over 1,300 in Europe
    

    Bob Loblaw,

    I found it very interesting to see how someone skilled in the art (you) can look at the details of where a weather station is located and what direction the wind blew from to show that claims of AC venting were incorrect.  It is always enlightening to see what scientists can determine from all the data that is available.  

    This is another example of why citing raw data doesn't make sense.  Analysis by scientists skilled in the art has so much more knowledge embedded in it.

40. Evan at 08:20 AM on 16 July 2026
    Fact brief - Do electric vehicles stop working in extreme heat?
    

    Thanks Baerbel for the adjustment.

    Like Doug, we've been successfully driving an EV for about 10 years, in both heat and cold. My favorite quip was during a very cold Minnesota winter day something commenting, "I didn't know EVs worked in the cold." I commented back that they start much more reliably than ICE cars in Minnesota, and they also heat up a lot faster!

41. ozthrox at 06:57 AM on 16 July 2026
    Home batteries could become the next must-have household appliance
    

    There is already a massive battery uptake in Australia, with the resultant improvement to grid reliability and a marginal lowering of energy prices as peaks and troughs are flattened. 

42. BaerbelW at 04:27 AM on 16 July 2026
    Fact brief - Do electric vehicles stop working in extreme heat?
    

    Evan @1

    Thanks for the pointer regarding the double negative, Evan! After checking with Sue Bin I updated the title to eliminate it while sticking with a question giving "No" as the answer. We'll also try to turn this into a rule of "avoid double negatives" for future fact briefs we create.

43. Doug Bostrom at 07:09 AM on 15 July 2026
    Fact brief - Do electric vehicles stop working in extreme heat?
    

    After about 10 years of experience w/an EV as primary automobile my observation is that cabin temperature control imposes a fairly modest effect on operations, using 5-10% of available battery in warmish conditions of say ~32C. Usually the hit isn't even visible on the realtime kW power instrumentation and only shows up in cumulative kWh stats after some hours of use. 
    
    On one occasion during prolonged parking with the vehicle "on" and in 41C ambient outside temp the kW hit shown via instrumentation became quite visible as work was done to keep the propulsion battery healthy (Bolt separately reports comfort cooling vs battery cooling energy usage).

44. Evan at 02:33 AM on 15 July 2026
    Fact brief - Do electric vehicles stop working in extreme heat?
    

    Usseful fact brief, but if we are trying to help people clearly understand fact briefs, maybe it's preferable to avoid using double negatives. Instead of writing

    "Are electric vehicles unable to function in extreme heat?, No"

    write instead

    "Are electric vehicles able to function in extreme heat?, Yes"

    Nothing wrong with the article, but might be a bit clearer by avoiding double negatives.

45. nigelj at 07:54 AM on 13 July 2026
    Six charts show how clean power was world’s largest source of new energy in 2025
    

    David-acct @3

    Michael Sweet: In 2021 the Texas debacle was caused by the failure of gas and nuclear units.

    David acct: The loss of electric generation from Gas and Nuclear plants was about 40% loss starting on 2/15/2021 and lasting until early 2/19/2021 (approximately 80 hours) where as the loss of electric generation from wind, solar was approximately 75% starting on 2/9/2021 and lasting until mid to late 2/19/2021 ( approximately 10 days).

    Nigel: Davids reply implies the main cause of the power failure was renewables. But this is incorrect. According to official investigative reports the main cause was failure of the gas supply system due to freezing up of supply lines and equipment due in turn to bad design by the grid authority. This took a lot of generation off line just when it was needed.

    https://www.ferc.gov/news-events/news/final-report-february-2021-freeze-underscores-winterization-recommendations

    The numbers David quotes for wind power output losses exceeding thermal and nuclear output is partly due to wind turbine equipment freezing up like with the gas system. But it also appears to include planned reductions in wind power due to the lack of wind. The system as a whole is designed to cope with this - provided the gas backup is working. So the real culprit was the failure with the gas supply. Nuclear power also had failures due to the freezing conditions.

    Moderator Response:

    [BL] Link activated

46. Bob Loblaw at 05:17 AM on 13 July 2026
    Eastern U.S. broils after heat wave kills over 1,300 in Europe
    

    Eric:

    Another factor for short-term variations in local temperature is sunshine. The data source you linked to for DCA in your earlier comment does not include radiation measurements (it's not critical for aviation weather), but it does include cloud cover information. (I don't know if this is from human observers or an automatic system.) Most of the day on July 4 had clear skies. Cloud cover began to increase late afternoon, and some clouds remain after the brief rain/thunder spell around 6:30pm.

    As for comparing temperatures regionally - still somewhat of a mug's game when it comes to absolute values. There is a reason why global temperature changes are evaluated using anomalies, not absolute values. There is an excellent 4-part series on this question starting here.

    Regional precipitation patterns are even harder, as so many precipitation events (especially summer thunderstorms) are so localized. It's easy for significant events to slip between observing stations (or park over one and make it look like the whole region is getting dumped on). In Canada, a Canadian Precipitation Analysis product (CaPA) combines surface measurements, radar, and forecasting model results to provide precipitation maps and such. Documentation here, page with links to current maps here. I do not know if the US produces anything similar for public consumption.

    As for the "exhaust plume" issue (to exhaust that discussion), there is much literature on the subject, from the perspective of pollution sources and how they spread locally or regionally. A basic model is the "Gaussian Plume". This link seems to give a decent overview. From a point source, the turbulent wind dynamics will spread a pollutant (or any property, such as temperature) both vertically and horizontally. As the spread increases, the concentration decreases. The further downwind, the harder it is to detect a weak source.

    If the plume is hot (as you would expect for a source of heat, as you originally supposed) the plume will also tend to rise through the cooler air. At greater heights, turbulent mixing is increased as the mixing eddies increase in size.

    What is seen at a point sink (e.g. a weather station) is the opposite: the further upwind you look, the wider the area the weather station sees. It will be getting air from a long line of (possibly differing) point sources.

    Pollution spread science  also looks at linear sources (think "highway vehicle exhaust in an urban area") and area sources (think "city surrounded by rural areas").

    It is for these reasons that I rapidly discounted your AC heat plume hypothesis - before looking at data and hypothesizing alternate explanations for the temperature pattern you identified.

47. michael sweet at 03:31 AM on 13 July 2026
    Six charts show how clean power was world’s largest source of new energy in 2025
    

    Frans,

    Hundreds of papers like Jacobson et al 2022 (sorry no link, my computer is down) show that all Europe, and the entire World, can produce All Energy using renewable sources.  Low wind periods can be accommodated with a combination of solar, hydro, storage and other technologies linked with a large grid.  The amount of storage needed is measured in hours, not days.  You have been misled by fossil fuel supporters. 

    In several of the graphs in the OP they show total energy, not capacity.  As discussed in the OP, showing total energy severely handicaps renewables since thermal resources waste two thirds of their energy as waste heat while renewable electricity is much more efficient.  None of the graphs show capacity, only generated energy is graphed.  

    Comparing the first graph of total energy supply it appears that nuclear supplies more energy than renewables.  The next to last graph of electricity (graphing terrawatt hours) shows renewables produce much more usable electricity than nuclear.  The additional energy in the first graph is released into the environment as waste heat. 

    Many people, including me, think it important to prevent killing a river by raising it's temperature.  This is a serious concern.  Thermal pollution kills environments.

48. michael sweet at 02:59 AM on 13 July 2026
    Six charts show how clean power was world’s largest source of new energy in 2025
    

    David-acct,

    We have previously discussed your citing raw data that doesn't support your claims instead of actual analysis of that data.  You have refused to answer my questions about how the raw data from France proved that nuclear reactors were shut down on weekends when you falsely claimed reactors were not shut down.

    It is not my job to analyse your data.  You must provide the analysis.

    Over 90% of the power lost in Texas was from thermal resources.  You are simply parroting the fossil fuel industry's lies.  If the Texas grid was linked to the rest of the country it would not have failed.

    Anecdotes about periods of low wind do not show that peer reviewed papers (cited hundreds of times) are incorrect.  If you want to claim Jacobson's paper was incorrect you must cite analysis of data.  Since all his code was published it would be easy for fossil companies to replicate his work using the conditions you refer to.  Since they have not shown Jacobson was incorrect it is most likely that they tried and found his system worked during the time periods you mention.  I note hundreds of other papers, using different models, show a completely renewable system can supply All Energy to the world.

    Find some analysis that supports your wild claims.  Links to raw data with unsupported claims the data shows something is simply promoting lies.

    Moderator:  David-acct has previously linked raw data claiming it supports his claims when I have proven the data contradicts his claims.  He refuses to answer my questions about his false claims.  He should answer my questions or withdraw his false claims before he starts the same BS on another topic.  He needs to cite analysis instead of making false claims about huge data sets.  He is wasting our time.

    I am sorry I didn't link our previous discussion on the nuclear thread, my computer is down.

    Moderator Response:

    [BL] Indeed. David-acct has been warned before about  providing links without giving much (or any) context or analysis.

    Most recently, he was warned about this on this comment and this comment. Just because this was over a year ago does not mean he gets to start his bad habit all over again.

49. Eric (skeptic) at 12:36 PM on 11 July 2026
    Eastern U.S. broils after heat wave kills over 1,300 in Europe
    

    Bob, my reason for bringing up only IAD and BWI along with DCA is I look at them daily for precipitation as part of early morning commentary at a local weather site.   While the June 12th 100 degree event happened I had the CWOP and other station site up looking for other 100 degree readings.  I came up with the plume explanation on that day based on wind switching to the west and nearby comparisons.

    I saw the Andrews max at 103 for the first time before the post with that link.  I was otherwise occupied on the 4th, and not able to look at the local stations.  A general explanation for July 4th is synoptic scale warming from thunderstorms blowing themselves out to the west, heating both DCA and a number of MD stations with hotter and a bit drier air.

    A more specific explanation for DCA is that the 9mph west wind at 5:40 droppd the dew point from 20C to 18C due to a drier air source and the potential of drier air mixing down.  You noted those possibilities and the complexity and I agree.  An AC exhaust plume is not a good explanation for that.

50. Philippe Chantreau at 11:44 AM on 11 July 2026
    Six charts show how clean power was world’s largest source of new energy in 2025
    

    I'm not one to condemn nuclear systematically, but also not one to give a pass to ERCOT. In the Texas outage of 2021, one could legitimately make the argument that the (much) larger share of gas/combined-cycle suddenly reduced, and the expectation that it is supposed to be baseload, i.e. not subject to weather, were factors.

    Taking a swipe at wind power like their politicians did was grandstanding nonsense. However, I noticed from the link provided by David acct that even coal dipped when the thing went down, so there is certainly an issue with the larger picture, including grid and exchanges with neighboring states. The integration of the European grid is a strength and France still has one of the lowest CO2/kw of electricity in Europe. However, they are facing problems, as the current very longand intense heat wave shows. 

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