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Comments 51 to 100:

  1. Interview with John Cook about misinformation and artificial intelligence

    David-acct:

    I notice that you did not actually refer to any studies containing data (and analysis) that supports your assertions.

    The study that nigelj linked to provides details on what they said. They declared:

    ...we are well situated to evaluate the two key descriptive questions underlying his assertion [the assertion being that [s]tates with mask mandates fared no better against Covid than those without]

    1. Did COVID-related death rates in states that had mask mandates differ from those in states that did not have mandates?

    2. Is there a difference in death rates between states with higher and lower levels of mask wearing?

    I think that their brief analysis supports their conclusions. Yes, there is a difference across states with or without mask mandates. They also went on to say:

    Correlation is not causation. Those states that had high levels of mask wearing generally had more stringent policies, as well as higher levels of social distancing and avoidance of crowds and public places. Further, there are certainly other, pre-existing, factors that influence COVID-related mortality numbers (like age of the population; density of housing, etc). Pulling apart that causal tangle is extremely difficult.

    Thus, they recognize that there are other factors to consider, and that full analysis is difficult. But their data fully supports their conclusion that the assertion they were testing was false.

    It is you that is now misrepresenting the data and analysis, pretending it made claims that it did not make. This is a classic case of misinformation - from you.

  2. Interview with John Cook about misinformation and artificial intelligence

    Nigelji @6

    Sorry I didnt provide better example of the methodology errors in the pro masking studies.  I presumed everyone respondig would better understanding of the effect of cofounding variables.  The number one factor in the speed of transmission of a respiratory virus is time and space.  None of the pro masking studies demonstrated any effort to account for behavior changes that affected time and space, at least none of the 30-40 studies i evaluated.  Of furhter note, in all the pro masking  studies, the gap in infections rates all evaporated after 6-10 weeks and most of the time the unmasked population had lower infections rates after the 10 period.  

    The Kansas county mask v non mask county study was quite notable for the lower infection rates post study period.

    That is my primary point - The calls to suppress "misinformation" is a call for censorship as evidenced government efforts during covid.  

    Everyone loses in those cases

     

     

     

     

  3. Interview with John Cook about misinformation and artificial intelligence

    Nigelji @6

     

    Your link to the covid rates by state/mask mandate is a perfect example of "misinformation" and how easy it is to get fooled by misinformation. While the data used is correct, it is also highly misleading.

    The study used total population to compute covid deaths per 100k. We all know covid deaths were heavily skewed to the elderly, As such the correct metric is covid deaths by age group. Properly adjusted for deaths by age group, there was virtually no difference of per capita covid deaths between any state regardless of masking policies. (with the exception of the 5 outliner states SD, ND, which had high much higher rates and NH, OR, & HI which had much lower rates even after adjusting by age group).

     

  4. Interview with John Cook about misinformation and artificial intelligence

    David-acct starts off his commentary with the one-liner, "Calls to suppress "misinformation" are in reality calls for censorship."

    I agree with what OPOF says at comment 8. I also watched the entire video. The video primarily uses the same word that appears in the text summary in the blog post: "counter". What does that mean? From Wiktionary: (to select the relevant definitions):

    Verb

    counter (third-person singular simple present counters, present participle countering, simple past and past participle countered)

    1) To contradict, oppose.

    Coordinate terms: counteract, counterargue, counterbalance, countervail

    ...

    3) To take action in response to; to respond.

    So, using "suppress" is a misdirection. It argues against a position that was not made in the text or video. As a counter-argument to David-acct's statement, I will say:

    Cries of "censorship!" are in reality attempts to silence counter-arguments. Typically, those that scream about censorshiip are the ones that want to suppress open discussion.

    The cry of censorship is sometimes framed as a "Free Speach!" cry. This usually amounts to a cry of "you aren't allowed to speak freely if you express disagreement, because I am supposed to be able to speak freely without opposition".

    [See how easy it is to use David-acct's tactics in the opposite direction?]

    Much of the rest of the video discusses how to recognize and counter various forms of misinformation. One of the points of discussion was how social media allows people to spread misinformation in short quips that appear convincing and appeal to emotion. Countering those bits of misinformation often requires lots of time, effort, and space as facts are presented.

    Guess what? David-acct is doing exactly that. Short, seemingly-convincing statements that discredit "virtually every pro masking study", and "vax efficiency". One-liners with no supporting references in an attempt to discredit the science. Exactly the kind of tactics that the video warns us about. And people have had to provide lengthy rebuttals, with links to more complete information, in an attempt to counter David-acct's misinformation.

     

  5. Interview with John Cook about misinformation and artificial intelligence

    Eclectic

    Saying vaccines dont reduce transmission was my bad. Thanks for the correction and information. My comment was a bit rushed. Should have proof read it.

  6. Interview with John Cook about misinformation and artificial intelligence

    Dr. Oliver has many short videos addressing many false claims about COVID vaccines.

    Each video has an accompanying comment listing the research cited in the video, so you can read those papers yourself.

  7. Interview with John Cook about misinformation and artificial intelligence

    Empirical evidence that mask-wearing policy is effective in reducing transmission of COVID, is Dr. Susan Oliver. Specifically this video, Mask debating is great, but some are NOT doing it right!, also explains some of the challenges in judging how well masks prevent transmisson, and explains that properly meeting those challenges reveals that masking and masking policies indeed are effective.

    An accompanying comment listing the research cited in the video, so you can read those papers yourself.

  8. Interview with John Cook about misinformation and artificial intelligence

    COVID Vaccines Do Reduce Transmission, per empirical evidence summarized by Dr. Wilson in Debunk the Funk. References so you can read the original documents he cites are in the comments of that video.

  9. Interview with John Cook about misinformation and artificial intelligence

    An excellent resource created by Dr. Wilson and others is a free onlline database that does not even require creating an account. It contains solid references to counter common COVID myths. Just type into your browser's URL bar, covidresearch.net. For an overview and example of how to use it, watch the 6-minute video by Dr. Wilson on Debunk the Funk.

  10. Interview with John Cook about misinformation and artificial intelligence

    It is important to distinguish different definitions of "infection":

    1. The infectious agent (e.g., virus) has landed on any infectionable portion of a persons' body, regardless of whether that landed agent has reproduced, and regardless of whether it can be detected by a given test.
      1. Masks, quarantine, isolation, sterilization, and similar methods reduce the probability of "infection" by this definition.
      2. Vaccines of course are not intended to prevent "infection" defined this way, because vaccines are physically capable only of improving the body's immune response to infectious agents that are on or in the body.
    2. The infectious agent has landed on an infectionable portion of a person's body and may or may not have reproduced, but in either case it can be detected by a "given" test.
      1. This definition has a subvariant definition for each type of test that is the definition's "given" test. For COVID, if an antigen test of a nasal swab is the "given" test, then a person may be declared infection free despite the possibility that a PCR test of that swab would have revealed infection. If a PCR test of a nasal swab is the "given" test, then it might be negative despite the fact that more sophisticated blood tests would yield a positive result. Often all such tests are combined with symptomology as part of the "given" test.
      2. Vaccines reduce the probability of "infection" by this definition, if the body's vaccine-heightened immune response keeps the viral load low enough to be undetectable by the given test, or wipes out all the virus before the load gets high enough to be detectable. Even if infection is detected by the given test, vaccines improve the immune response enough for viral load to remain so low that probability of any symptoms, probability of frequent or severe symptoms, and infectiousness, all are lowered at least some and often dramatically.

    Unfortunately that distinction is assumed rather than repeatedly stated explicitly by many people, including many otherwise excellent science communicators such as Dr. Wilson of Debunk the Funk. But that distinction is crucial for understanding questions of whether masks and vaccines prevent infection.

  11. Interview with John Cook about misinformation and artificial intelligence

    David-acct @3, in addition to the replies of other people:

    It is important to distinguish among the efficacy of a mask worn properly by a single person, self-reports of people claiming they wear masks, the type of mask, the properness of its fit, the properness of its wearing, the amount of time and circumstance in which it is worn, and policies that encourage or require mask wearing.

    An N-95 (or KN-95) mask worn properly, repeatedly has been proven by solid, physical, experiments to reduce both emission of viruses and other infectious agents past the mask, and inhalation past the mask.

    Throwing in all the other variables I listed, getting good evidence becomes more difficult. Nonetheless, there is solid, utterly reliable evidence of the efficacy of mask wearing. Of course the efficacy decreases with decreasing mask quality, time of wearing, and properness of wearing. And of course policies that encourage or mandate wearing are not adhered to 100% but that does *not* mean those policies are 100% useless.

    Here is a 10 minute video from Debunk the Funk with evidence of all the above. See the comments of this video for references so you can read the studies yourself.

  12. One Planet Only Forever at 13:20 PM on 8 December 2024
    Interview with John Cook about misinformation and artificial intelligence

    David-acct @1

    I offer this response that is more ‘on-topic’.

    I have read the post and watched the video. Your opening sentence does not appear to be on-topic.

    The only mention of efforts to suppress information that I came across is near the end of the video:

    • The discussion starting at 52:25 provides an example of the objective of work like John Cook’s - being to help people to be better critical thinkers, less likely to believe misinformation.
    • The discussion starting at 54:15 gets into the matters of attempts to suppress messaging. The evidence indicates that people who want to benefit from the popularity of misunderstanding, and reduced popularity of the fact-based better understanding are the ones who attempt to suppress awareness and understanding of the evidence of fact-checkers and misinformation researchers.

    So, the evidence appears to indicate that you are exhibiting the behaviour you complain about in your concluding sentence @1. Your comment @1 appears to be a misinformation effort trying to discredit, distract from, or suppress efforts that would help people be more aware and better understand how they can be less harmful and more helpful to Others.

  13. Interview with John Cook about misinformation and artificial intelligence

    Nigelj @6 :-

    A degree of correction, please  ~ many vaccines can achieve a huge reduction in transmission rates and/or in individuals' severity of disease.

    Depends on the disease type . . . ranging from the super-transmissible such as measles, to the low-transmissible such as leprosy [no vaccine yet, unfortunately].   You are right that, for some diseases, the individual's severity of infection can be smaller if the initial infecting dose is small   (see the history of small-dose "variolation" that was used in the centuries before the highly-effective modern smallpox vaccination was identified ).

    So for covid, using a mask may not necessarily prevent all transmission, but it may result in a smaller infecting dose and may result in a milder severity of disease for that individual . . . and that's something that might not show in the testing of masking, since the results tend to be measured in "got infected" versus "didn't get infected" categories.

    But that's not showing in David-acct's comments  ~ I am not sure whether he is taking an Ultra-libertarian-and-damned-to-everyone-else attitude, or whether he's simply got his science wrong also.

  14. Interview with John Cook about misinformation and artificial intelligence

    David-acct says: "Eclectic since you requested an example, virtually every pro masking study had serious flaws and methodology errors"

    You provide no evidence for your claim. Maybe think about what masks do. Masks reduce droplets getting through, and much of the virus is in the droplets (with covid some is airborne as well). This reduces the viral load on the lungs and is thus going to reduce the severity of the illness. Its not rocket science. Masks work. Loccations with high mask use were shown to have lower mortality rates. For example:

    www.covidstates.org/blog/did-mask-mandates-reduce-covid-deaths

    David-acct says : "eclectic - same issues with vax efficiency, virtually no reduction in infection rates and transmission rates, though did have some benefit in the reduction of severity and death for those who were at high risk.

    Most vaccines have little or no effect on infection and transmission rates. The purpose is to reduce the severity of the illness. And your implied claim that vaccines only reduce severity of illness in high risk people is completely unsubstantiated and defies commonsense and simple logic. Medications generally reduce severity in people regardless of their age group or underlying general state of health. I see no reason why vaccines would be different. Remember plenty of unvaccinated healthy or young people  died of covid or got very sick! The point is vaccines help everyone, but of course they are particularly helpful for older or at risk people. 

    I will explain why America had such a high covid mortality and illness rate Many millions of people (tending to be on the right of politics) didn't wear masks, or socially distance, or self isolate, or get vaccinated. So they died. What a surprise. In New Zealand we mostly did the opposite and had a much lower mortality rate.

    I realise Americans have this freedom thing where they utterly refuse to suffer any restrictions even temporarily. Its crazy and its got like an obsession. But you can't see it.

  15. Interview with John Cook about misinformation and artificial intelligence

    David-acct @3 ; @4  :-

    No , David , you need to do a lot better than that.

    e.g. Vaccines.   Fortunately, the scientists had been working on developing the novel concept of mRNA-type vaccines over about a 5-year period before covid's surprise arrival.   To his great credit, President Trump quickly poured government money into an acceleration of R&D of a mRNA covid vaccine.   [Yes, at times he acts on the advice of experts!  But for the future, one might worry about the influence of proposed Head Health Honcho RFKjr.   ;-)   ]

    The result ~ covid vaccines that were (like all vaccines) less than perfect but still highly effective at the individual and societal level.  Saving money and giving a large reduction in expected covid deaths in the elderly, and a very large reduction in non-fatal disabilities such as myocarditis and Long-Covid.

    # Personal anecdote :  Previously I have had 5 or 6 covid vaccinations (one does lose count, eh ).   And about 14 months ago, I came down with covid ~ so slight, that I wan't sure I was ill  (a headache so slight I wasn't sure the headache was actually in existence, and a temperature so slight that I couldn't be sure my neck felt any warmer than normal ).   But the nasal swab home-test kit showed a positive for covid.   And I have been well since.

    David , the covid viruses are very contagious  ~  not quite as badly as measles, where you are at risk from someone walking down the other side of the street [minor exaggeration! ].

    Sure, wearing a filtered-air spacesuit helmet might give you 100% protection. ~  but if wearing paper-type facemasks reduces your risk of covid infection by around 50%  (as common sense would suggest for aerosol-type infections)  then it would be foolish to avoid masking up until some super-precise scientific testing had been completed.  For at least in the early pandemic, and/or in crowded spaces, and/or in hospital care settings, etcetera  ~  until such time as vaccinations & herd immunity had improved the situation (i.e. as today).

    Rejecting vaccines and appropriate maskings . . . would be as foolish as rejecting a bullet-proof vest because the vest "ain't 100%" .

    In the risky situation ~ how is a bullet-proof vest a "misinformation"?

  16. Interview with John Cook about misinformation and artificial intelligence

    eclectic - same issues with vax efficiency, virtually no reduction in infection rates and transmission rates, though did have some benefit in the reduction of severity and death for those who were at high risk.  

  17. Interview with John Cook about misinformation and artificial intelligence

    Eclectic since you requested an example, virtually every pro masking study had serious flaws and methodology errors

  18. Interview with John Cook about misinformation and artificial intelligence

    David-acct @1 :

    Human history, human psychology, demonstrate that the world is not black-and-white.  Nuances exist.  Doctrinaire slogans ~ such as "Four legs good, two legs bad" (or even "censorship bad, toxic free speech good") ~ are not a healthy way for society to exist.  Major problems result.   Better, if common sense is used.

    [... Insert cliched quote by Voltaire ...]

    Getting slightly off-topic here, David  ~  but could you add a list of egregious covid-related official authoritative pronouncements you were thinking of as produced great harm (and were unreasonable, given the scant knowledge of the virus's properties at the early stages of the pandemic) ??

  19. Interview with John Cook about misinformation and artificial intelligence

    Calls to suppress "misinformation" are in reality calls for censorship.

     

    As evidenced during the Covid pandemic, almost all of what the experts and government authorities labeled "misinformation" turned out to be correct while much of the official authoritive pronouncements turned out to be false or highly misleading. (with the exception of Ivermectin and hydroclorox  - All those postive claims did turn out to be false).

     

    Typically whenever someone is screaming about misinformation, they are the ones guilty of the charge.

  20. How Plastics Fuel Climate Change

    The talks in Busan, South Korea, to secure a Plastics Treaty as a start to reduce plasstic production have ended in failure.

    Why, resistance by the usual suspects (fossil fuel states), including Saudi Arabia, Iran and Russia.

    Link to article....

    https://www.theguardian.com/environment/2024/dec/02/countries-call-for-binding-targets-to-cut-plastic-production-busan-talks

    Moderator Response:

    Link activated.

    The web software here does not automatically create links. You can do this when posting a comment by selecting the "insert" tab, selecting the text you want to use for the link, and clicking on the icon that looks like a chain link. Add the URL in the dialog box.

  21. CO2 effect is saturated

    CallItAsItIs @842,

    That was not a response to my question @841 which, posted eight minutes before your comment @842, appears to have prompted your comment @842 as a reply.

    You ask "Now who's changing laws of physics!?" Do note the quote you read @808 present @842 was my interpretation of your argued position. The full quote runs:-

    "The argument that was being made by commenter CallItAsItIs ... is to suggest that the likes of Kirchoff's Law can be ignored because the atmosphere is warming and thus Kirchoff's Law and its ilk which apply in a state of equilibrium do not apply under AGW. Of course, that situation should mean you adapt the physics such that they do apply, an adaption which commenter CallItAsItIs feels is not required as he can instead happily applies his own nonsense as an alternative."

    If you feel AGW is adding some fundamental problem for the use of Kirchoff's Law, perhaps AGW can be ignored for this description of the physics of the atmosphere. Consider instead the pre-industrial pre-AGW climate: does that fix your objection to the use of Kirchoff's Law?

    And note the more trivial question I posed @841remains unanswered.

    Moderator Response:

    Until such time as CallItAsItIS provides a numerical calculation of the purported effects he claims exist, and shows that it agrees with measurements, expect any and all comments from CallItAsItIs or reacting to him to be deleted.

  22. CO2 effect is saturated

    MA Rodger @841

    Your correction to the quote at 831 certainly seems reasonable.

  23. CO2 effect is saturated

    michael sweet @838

    Your claim at 835 that frequency is conserved directly contradicts your previous claim that all the 15 micron photons are absorbed in the lower atmosphere. Making contradictory claims voids your entire argument.

    What do you mean "frequency is conserved"?  I never made any such claim, not in 835 nor any place else!

    Moderator Response:

    You don't even know what it means when you say "the law of conservation of energy applies to each and every frequency individually", do you?

  24. CO2 effect is saturated

    MA Rodgers @808

    ... and thus Kirchoff's Law and its ilk which apply in a state of equilibrium do not apply under AGW. Of course, that situation should mean you adapt the physics such that they do apply, ...

    Now who's changing laws of physics!?

    Moderator Response:

    Everybody except you knows the answer to that question.

  25. CO2 effect is saturated

    CallItAsItIs @840,

    Perhaps we can work from that apparent point of agreement.

    To correct the quote @831 a little

    "When a CO2 molecule absorbs a photon it will hardily ever emit another photon. The energy from the photon is distributed to other molecules."

    The reason for this is because the average relaxation time required for the excited CO2 molecule to emit another photon is many times longer than the average time before it will be in collision with other air molecules which will neutralise the excitation and thus convert the excitation energy into thermal energy within the gas mollecules.

    So CallItAsItIs, I would assume someone with a PhD in Physics will have no problem with wrapping their head round the amended quote and the explanation and give it a yea or ney (and if 'ney' the reason why).

    (And apologies to Moderators for this late attempt to reach some agreement.)

  26. CO2 effect is saturated

    michael sweet @831

    When a CO2 molecule absorbs a photon it does not emit another photon. The energy from the photon is distributed to other molecules.

    Agreed!, but Bob Loblaw, Charlie_Brown, and a few others seem to feel I am breaking Kirchhoff's Law in making such a claim.  Could you maybe straighten them out in this matter.

    Moderator Response:

    This has been explained to you many times in this thread.

  27. CO2 effect is saturated

    Michael Sweet @837

    Thanks. I wondered about that imbalance in the budget. I didn’t know if it was the difference between input and outputs or whether it was calculated from the radiative balance. Radiant energy calcs are precise, so I prefer using MILIA for that purpose or using the forcings from the ICPP. A small difference between large numbers with uncertainties is not so precise. Anyway, it is the right order of magnitude for the calculated radiative imbalance.

    Moderator Response:

    No more please. Attempting to explain physics to Callitasitis has been futile. He/she needs to show how their wierd way of thinking reproduces existing measurements or better still correctly predicts measurements of radiation. So far Callitasitis has resisted tying their calculations to measurements and this thread is pointless till that happens.

  28. CO2 effect is saturated

    Callitasitis:

    Your claim at 835 that frequency is conserved directly contradicts your previous claim that all the 15 micron photons are absorbed in the lower atmosphere.  Making contradictory claims voids your entire argument 

    In any case the claim frequency is conserved is obviously false.  Incoming energy is visitlight while outgoing energy is IR light.  Frequency is obviously not conserved.

    I cannot believe that someone with a physics degree would make such an obvious, basic error.  

  29. CO2 effect is saturated

    Charlie Brown:

    Your points to Callitasitis are on point 

    I think your addition has an error.  From the diagram at 827:

          341.3 (solar in) =

          101.9 (reflected) + 238.5 (ir out) +0.9 (absorbed)

    The absorbed is the energy that heats the Earth.  When you rounded the numbers they didn't add up.  I do that all the time.

  30. CO2 effect is saturated

    CallItAsItIs @ 835

    Unfortunately, I am completely lost by this explanation. We are talking about the Energy Budget diagram @753 and @827, aren’t we? Thermal is convection from the surface, 17 W/m^2. Evapotranspiration is 80 W/m^2, and Latent heat for condensation is 80 W/m^2. Those energy streams redistribute energy in the lower atmosphere and affect the atmospheric temperature profile, along with the lapse rate. The Response @827 already explained it correctly. Note that an energy budget describes the energy flows within the overall global system. If you are talking about the overall global system energy balance, then the boundary is at the TOA. The intermediate streams in the lower atmosphere are not needed. The energy balance becomes:

    Solar In (341 W/m^2) = Solar Reflected (102 W/m^2) + IR Out (239 W/m^2)

    IR Out is the full IR spectrum because it includes IR emitted by the surface that is not absorbed and re-emitted by greenhouse gases.
    Conservation of energy does not apply to each and every frequency individually. Kirchhoff’s Law explained @756 and elsewhere allows for collisions between molecules and energy exchange by conduction. For a small, localized packet of isothermal atmosphere, absorptance will equal emittance. But since there is a temperature change with altitude, it is conservation of energy, not conservation of photons.

    It is clear that you did not understand my description of AWG because you say that we are only interested in 14-16 microns. But AWG also includes strengthening of weak CO2 emittance lines between 13-14 microns and 16-17 microns, as illustrated @788. And warming of the surface increases caused by increasing CO2 increases IR from all of the transparent lines also. The atmospheric spectrum was shown in @819 and for different altitudes @731.

    My perspective now is that you have no business critiquing AGW because we are not even close to talking about the same thing. We seem to be hopelessly talking past each other.

  31. CO2 effect is saturated

    Response @827

    Well, you will be pleased to know that every energy flow shown in your diagram is EMR — just different frequencies.  And since our topic is the CO2 greenhouse effect, we are only interested in the absorption band from 14-16 microns.  Finally, since we are not in the realm of nonlinear optics, the law of conservation of energy applies to each and every frequency individually as well as collectively.  I hope clears up your understanding and perspective on this issue.

    Moderator Response:

    I'd be tempted to ask what frequency evaporation happens at, but I know there isn't an answer to that, because it isn't EMR.

    The only understanding you have cleared up is that you are eternally misinformed.

  32. CO2 effect is saturated

    CallItAsItIs @832

    If you understand the fundamental principles, then perhaps you are not understanding how the parts of AGW fit together and do not violate any of them. Help us out here. Just what part of AGW is it that you think violates a fundamental principle? Kirchhoff’s Law, which I thought was your stumbling block, was well covered in great detail by Bob Loblaw @830 and Michael Sweet @831. Perhaps you are confused about the word “atmosphere” as defining the system energy balance. @827 you say:

    “The problem with this claim is that it is only by EMR that energy enters and leaves the atmosphere. Conduction and convection only redistribute energy already within the atmosphere, and therefore give a sum total contribution of zero to the thermal energy contained in the atmosphere.”

    It is correct that only radiant energy enters and leaves the overall global system at the Top of the Atmosphere (TOA) where the global system includes the atmosphere plus the surface. However, you seem to exclude the surface by saying that conduction and convection only redistribute energy already in within the atmosphere. As shown in the energy budget diagram, convection and evaporation transfer energy from the surface to the atmosphere. Total IR flux leaving the TOA is determined by the temperature profile of the atmosphere and the surface. The intensity of the total IR spectrum at the TOA is integrated to give IR heat flux. Do not think that AGW is caused only by absorbing IR in the lower atmosphere. It is caused by reducing IR loss to space which then has to be compensated by accumulating energy until IR from a warmer surface balances the reduction through the full CO2 absorption band. The warmer surface heats the lower atmosphere.

  33. CO2 effect is saturated

    CallItAsItIs:

    As a Ph.D. physicist...

    You need to ask for your money back.

  34. CO2 effect is saturated

    Response @825

    ... would bother to try to learn it.

    As a Ph.D. physicist, I have already learned the fundamental principles claimed in this AGW stuff, and I resent this comment of yours.  The issue at hand is that after careful review of the SkS "rebuttals" to the CO2 band saturation effect, I believe they violate at least one very fundamental physical principle and am trying to get this matter resolved.  And your snip-happy attitude isn't helping any.

  35. CO2 effect is saturated

    Callitasitis at 826:

    This is the basis of your misconceptions.  When a CO2 molecule absorbs a photon it does not emit another photon.   The energy from the photon is distributed to other molecules.  New photons are emitted according to the temperature where they are emitted.  You are focused on the incorrect issue and you do not understand how energy flows through the atmosphere.  IndividuaI photons are not important.  I will try to explain it to you again.

    The surface of Earth emits radiation according to its temperature.  Let us say it is 290K.  I will look at the later of air 1000 meters high.  As you point out, all the upwelling energy is absorbed.  Since I am now higher this layer is colder, it is only 285K.  I look at this layer from above.  I see that this layer emits 15 micron radiation according to its temperature.  Since it is colder than the surface it emits less energy.

    Now I look at the next 1000 meters of the atmosphere.  It absorbs all the upwelling radiation.  It is only 280K so it emits less upwelling radiation.

    This process goes up to the top of the atmosphere with each layer emitting less energy up.  The incoming  energy from the Sun makes the Earth about 275K.  At the top of the atmosphere the energy emitted averaged over all wavelengths of radiation must be 275K due to the law of conservation of energy.  Incoming energy must equal outgoing energy.  For the purpose of this discussion I will say that at 3000 meters the temperature is 275K.

    The key issue is the concentration of CO2.  The top of the atmosphere is determined by the concentration of CO2.  The concentration of CO2 determines the amount of energy emitted up.  If the concentration of CO2 is lower the TOA is lower, if the concentration of CO2 is higher the TOA is higher.  The concentration of CO2 is lower when you go up in the atmosphere because the pressure is lower.

    Now I add more CO2 to the atmosphere. I do not care about the first 2999 meters of the atmosphere, I only care about the top of the atmosphere

    At 3000 meters there is now more CO2 so more upwelling energy is absorbed.  (upwelling energy from 2,999 meters).  This reduces the energy emitted to space.   In order to conserve energy the top of the atmosphere has to move higher where CO2 is lower.   Now it is 275K at 3,100 meters instead of 3,000 meters.  The top of the atmosphere must stay 275K to conserve energy.  The CO2 concentration is lower since the pressure is lower.

    The temperature of the atmosphere is determined by the lapse rate.  The lapse rate is a physical property of the atmosphere.  It is measured as 5K per 1000 meters.  That means that if you go up 1000 meters the air is 5K colder.

    When it was 275K at 3,000 meters it was 290K at the surface.  Now, because the CO2 has increased, it is 275K at 3,100 meters.  Since the top of the atmosphere is 100 meters  higher the lapse rate forces the entire atmosphere to increase  by 0.5K.  It is now 290.5K at the surface.

    The top of the atmosphere is extremely sensitive to the concentration of CO2.  It doesn't matter that the first 10 meters on the atmosphere absorb all upwelling 15 micron radiation from the surface.  The upwelling radiation is replaced by black body radiation originating in the atmosphere.  Focus on the top of the atmosphere.

    You have not taken advanced atmospheric physiior chemistry.  Reading a little on the Internet does not make you smarter than all the scientists in the world.  Accept that you do not understand the energy flow in the atmosphere.

  36. CO2 effect is saturated

    I have been staying out of this, to let the moderators try to control the situation, but CallItAsItIs's latest diatribes continue to make the same basic mistakes that he started with, so I"ll attempt once more to point out his main errors.

    The moderator reposted the Trenberth Energy diagram in response to comment 827. I had previously discussed this diagram in comment 772, over a week ago. CallItAsItIs is under the illusion that no energy enters the atmosphere except via radiation. In the diagram, we see 17 W/m2 entering the atmosphere from the surface via "thermals", and 80 W/m2 entering the atmosphere via "evapotranspiration". These values are not zero.

    • The "thermal" part of this is heat transfer by conduction, as a hot(ter) ground or water surface heats the cool(er) air over that surface. No radiation is involved.
    • The "evapotranspiration" part of this is the movement of energy as a result of the evaporation (or sublimation) of water (liquid or solid) at the surface (or from plants - "transpiration"), the movement of water vapour into the atmosphere, and the condensation (or sublimation) of that water vapour back into liquid (or solid), releasing the latent heat of vaporization back into thermal energy. No radiation is involved.
    • These energy transfers from the surface into the atmosphere are important.

    CallItAsItIs continues to misunderstand the importance of non-radiative energy transfers in the atmosphere, by saying they don't matter, as they just redistribute energy, not adding it. He's wrong about adding it, but he is also wrong about the importance of redistributing it.

    • When looking at a layer of the atmosphere, its temperature (and any changes to that temperature) is a response to any source of energy from layers above and below it that gets converted to thermal energy within that layer. It does not matter whether that energy gets there because of radiation, conduction, condensation, etc.
    • Things that add thermal energy to a layer include:
      • absorption of radiation (IR or solar)
      • bring warm are into the layer and move cooler air out (convection)
      • conduction (can be ignored except directly at the surface, since convection is far more important)
      • condensation of water vapour (when the water vapour was evaporated elsewhere and carried into this layer by convection - i.e., move moist air in, replacing drier air).
    • Things that remove thermal energy from a layer include:
      • emission of radiation (that then leaves the layer)
      • convection (move warm air out of the layer, replace it with cooler air)
      • evaporation of water (and moving the vapour out of the layer)
    • Whenever convection moves energy from one layer to another (thermal or in the form of latent heat in water vapour), that will have an effect on the emission of IR radiation within that layer.

    Now, let's take another look at CallItAsItIs's misunderstanding of the Schwarzchild equation and Kirchoff's Law. Again, previously posted, we have Schwarzschild's equation:

    Schwartzschild equation

    This is a differential equation, telling us the change in radiation in a layer (infinitely thin, only ds units thick, as Calculus is wont to do).

    • If dIλ is >0, the layer is gaining energy via radiation at this wavelength.
    • If dIλ is <0, the layer is losing energy via radiation at this wavelength.

    There are two terms in it (in the middle form):

    • The first is the emission of radiation, according to Planck's law.
    • The second is the absorption, related to Beer's Law.

    ...but we have not really talked about what all the variables mean. Copying from the Wikipedia page:

    n is the number density of absorbing/emitting molecules (units: molecules/volume)
    σλ is their absorption cross-section at wavelength λ (units: area)
    Bλ(T) is the Planck function for temperature T and wavelength λ (units: power/area/solid angle/wavelength - e.g. watts/cm2/sr/cm)
    Iλ is the spectral intensity of the radiation entering the increment ds with the same units as Bλ(T)

    Let's make a few points:

    • Emission requires knowledge of the layer temperature. Any energy flow that affects temperature (not just radiation absorption) will change the emission rate.
    • Absorption does not have  a temperature term.
    • The two terms will only balance at one specific temperature. Any other temperature will lead to an imbalance - i.e., dIλ will not equal zero.
      • "Any other temperature" can and wll occur when there are other energy transfers besides radiation. This is why CallItASItIs is wrong,wrong, wrong, when the thinks that other energy transfers are not important.
    • We also notice that both the emission and absorption terms include the variable σλ - the "absorption cross-section".
      • How does an "absorption" term end up in the emission calculation? Because of Kirchoff's Law.
      • Kirchoff's Law does not say that absorption = emission. It just says that the efficiency of absorption is equal to the efficiency of emission.
        • CallItISsItIs gets it wrong, wrong, wrong when he thinks Kirchoff's Law requires that every absorbed photon must be immediately emitted again.
          • Absorbed photons add there energy to the local thermal energy.
          • Emitted photons take their energy from the local thermal energy.
          • The two processes are largely independent, linked only through thermal conditions, of which radiation absorption is only one part.
          • And thermal conditions depend on absorption of other wavelengths, not just the wavelength that we are currently looking at using Schwarzschild's equation.

    Although CallItAsItIs seems to accept that Schwarzschild's equation is reasonable, he rejects Kirchoff's Law, in spite of the fact that Schwarzschild's equation has Kirchoff's Law as one of its essential parts. In order to reject Kirchoff's Law he throws out bogus "laws of thermodynamics" and "thermal equilibrium" claims that have been criticized many times:

    • Conservation of energy must include all energy transfers - not just radiation, and especially not just an isolated wavelength of radiation.
    • Kirchoff's Law is applicable when we have local thermodynamic equilibrium.

    At this point, it is clear that CallItAsItIs suffers from two major intellectual issues:

    • He does not understand the details of individual bits he reads.
    • He does not understand how these individual bits are related to each other.

    I don't think there is much more we can do help him understand. The resistance is extremely strong.

  37. CO2 effect is saturated

    CallItAsItIs @827 ; @828 ; @829  ~

    [snip]

    You are outdoing yourself.  Not two, but now three (3) repeated posts within 2 hours.

    Still, it does supply some reassurance that you aren't an A.I.

    No A.I. that I am aware of, would make such errors.  Nor would an A.I. keep repeating the multiple scientific errors that you keep repeating. 

    An A.I. of the most modern sort, would change and adapt its responses, when those errors were pointed out.

    Moderator Response:

    This does not help.

  38. CO2 effect is saturated

    Charlie_Brown @825

    Forget about conserving only radiant energy and remember that conservation of energy includes conduction and convection.

    The problem with this claim is that it is only by EMR that energy enters and leaves the atmosphere.

    [snip]

    Conduction and convection only redistribute energy already within the atmosphere, and therefore give a sum total contribution of zero to the thermal energy contained in the atmosphere. I believe I explained this in one of my posts which the moderator removed.

    I think your blind spot is assuming that radiation in the CO2 absorption band is absorbed and disappears somewhere within about 10 meters of the surface.

    No, that is not correct. I know that such thermal energy is somewhere within the atmosphere. It's simply a point that I haven't mentioned just yet since it is not relevant to solving the Schwartzschild equation. One thing worth pointing out, however, is that while adding massive amounts of CO2 to the atmosphere does not increase the overall CO2 temperature forcing, the entire radiated energy from the 15 micron band would be concentrated within just a few meters from the surface. From this, one might think that the surface would be too hot to touch! And that might be true except for one thing — convection. In addition to the surface being so hot, steep temperature gradients would form which would then result in steep pressure gradients. Then, according to the Navier-Stokes equation, the pressure gradient would drive a fluid velocity near the surface which carries away the excess heat. Anyway, I just wanted to make the point that I have not forgotten about that heat within 10 meters of the surface. It simply hasn't been a compelling issue just yet.

    Moderator Response:

    No matter how many times you say this, it is still wrong.

  39. CO2 effect is saturated

    Charlie_Brown @825

    Forget about conserving only radiant energy and remember that conservation of energy includes conduction and convection.

    The problem with this claim is that it is only by EMR that energy enters and leaves the atmosphere. Conduction and convection only redistribute energy already within the atmosphere, and therefore give a sum total contribution of zero to the thermal energy contained in the atmosphere. I believe I explained this in one of my posts which the moderator removed.

    [snip]

    I think your blind spot is assuming that radiation in the CO2 absorption band is absorbed and disappears somewhere within about 10 meters of the surface.

    No, that is not correct. I know that such thermal energy is somewhere within the atmosphere. It's simply a point that I haven't mentioned just yet since it is not relevant to solving the Schwartzschild equation. One thing worth pointing out, however, is that while adding massive amounts of CO2 to the atmosphere does not increase the overall CO2 temperature forcing, the entire radiated energy from the 15 micron band would be concentrated within just a few meters from the surface. From this, one might think that the surface would be too hot to touch! And that might be true except for one thing — convection. In addition to the surface being so hot, steep temperature gradients would form which would then result in steep pressure gradients. Then, according to the Navier-Stokes equation, the pressure gradient would drive a fluid velocity near the surface which carries away the excess heat. Anyway, I just wanted to make the point that I have not forgotten about that heat within 10 meters of the surface. It simply hasn't been a compelling issue just yet.

    Moderator Response:

    Leaving a portion of this intact. Once again, your assertion that no energy enters or leaves the atmosphere except by radiation is wrong. This is only true at the top of the atmosphere. It is not true at the surface. And this has been explained to you several times. Look at this diagram, once again.

    Trenberth Energy diagram

  40. CO2 effect is saturated

    Charlie_Brown @825

    All right — This whole matter of Kirchoff's law seems trivially simple to me, so I guess I must be missing something.  Therefore, I seek your great wisdom in order to understand this law and its implications correctly.  Now, my understanding is that for each photon that is absorbed, an identical one is emitted, and vice-versa.  So, if a CO2 molecule absorbes a photon and emits one exactly like it, how much of the energy from the absorbed photon is available as heat energy to warm the atmosphere?

    Moderator Response:

    I will leave this intact, even though it is not the numerical calculation we are asking for, but this is a prime example of how you continue to get things wrong.

    Kirchoff's Law does not say what you imply here.

  41. CO2 effect is saturated

    CallItAsItIs @823

    Schwartzchild equation is correct. Beer's Law applies. Kirchhoff's Law applies. Conservation of energy applies. Planck Distribution Law applies. Stefan-Boltzmann Law applies. You need to figure out why your conclusion is not consistent with the fundamental laws of radiant energy. MA Roger certainly did not agree that any of those laws do not apply and did not concur that you have used the equation correctly.

    A good place for you to start would be to go back and re-read previous posts because the answers are there. Hint: Beer's Law applies to attenuation of the source photons. Kirchhoff's Law describes re-emission of those photons. CO2 molecules at a specified temperature absorb and emit photons equally, else internal energy would be accumulating and temperature would be changing. Forget about conserving only radiant energy and remember that conservation of energy includes conduction and convection. I think your blind spot is assuming that radiation in the CO2 absorption band is absorbed and disappears somewhere within about 10 meters of the surface. That would not be consistent with conservation of energy.

    Moderator Response:

    As you point out, the answers are all there in previous comments, if CallItAsIt is would bother to try to learn it.

  42. CO2 effect is saturated

    Philippe Chantreau @822

    [snip]

    I really do not see how it is anybody else's responsibility to help.

    Of course it is not anyone else's responsibility to help. I was hoping, however, that with this being a climate site, somebody here more knowledgeable in climate science than me would be anxious to help. This is how science progresses, and a true scientist would want issues and conflicts resolved as opposed to censoring the person who discovered it. But with the disrespect, unfair censoring, and just plain hostility shown me, I've obviously overestimated the "experts" at SkS and probably the entire AGW community.

    Textbooks have all the theory. Classes covering radiative transfer exist in many educational institutions. The LBLRTMs are physical models. The model predictions exist before the measurements to validate them take place. It takes a lot of painstaking work to build them but LOTRAN and MODTRAN are accessible to the public.

    Then what do we need scientists for!?

    Moderator Response:

    Still can't get it right.

  43. CO2 effect is saturated

    MA Rodger @819

    [snip]

    So, you concur then that the Schwartzschild equation is the correct equation to solve in order to determine the spectral intensity Iλ. Furthermore, since this equation is a first order linear DE and the value of Iλ at s=0 is given, that solution is unique. Therefore, since this solution is not compatible with Kirchoff's law (unless we give up energy conservation), it means that Kirchhoff's law does not apply for this system. Thanks! You have been quite helpful.

    Well Moderators, it seems that MA Rodger has concurred that my model using the Schwartzschild equation is correct and I have the calculations ready. It turns out that if we double the current CO2 concentration, the effect it would have on the CO2 temperature forcing is, for all practical purposes, a big zilch. Therefore, I have completed your request so we can now stop blocking my posts.

    Moderator Response:

    Same incorrect conclusions, with no numerical result, deleted.

  44. Sabin 33 #5 - Is solar energy worse for the climate than burning fossil fuels?

    Thank you for your thoughtful and productive critique, walschuler. 

    Sabin is actively maintaining this collection and we are delighted to help with that. We'll pass along your comments and work with Sabin to address them. 

    Published research literature will provide our improvements; if you have relevant references please do post them in this comment thread. As is said of software, with enough eyeballs all bugs are shallow. :-)

  45. Philippe Chantreau at 05:03 AM on 6 December 2024
    CO2 effect is saturated

    I really do not see how it is anybody else's responsibility to help. Textbooks have all the theory. Classes covering radiative transfer exist in many educational institutions. The LBLRTMs are physical models. The model predictions exist before the measurements to validate them take place. It takes a lot of painstaking work to build them but LOTRAN and MODTRAN are accessible to the public.

  46. CO2 effect is saturated

    Philippe Chantreau @818

    I understand your concerns

    [snip]

    and I have had them too. We must realize, however, that in setting up a model, there are typically a bunch of unknown that must be pinned-down somehow. Normally, they are tweaked for best agreement with observation, and if good agreement is obtain over a wide range of data, then we say we have a good model. There is nothing "wrong" with that but we must realize its limitations. What works well now may not give such good results in a few years. This is why a "good" model must be "maintained" or "updated" every so often and may not be meaningful for long-term predictions.

    In my work, however, I am not building a model for comparison with observations. I am only trying to assess the effect of increased atmospheric CO2 content on the total greenhouse forcing in order to establish whether this effect is saturated. Therefore, I only determine the CO2 greenhouse forcing assuming that all essential inputs are given. The idea then is to keep this problem as simple as possible, solve it on a first-principles level, and then test the solution over a realistic range of input parameters.  I did not include convection in my analysis since it does not affect the amount of new heat entering the system, but only where it goes.  Also, since convection depends on fluid velocity, the model would need frequent updates and be more of a complication than what it is worth.  Therefore, a comparison of my results with observations and/or the Feldman et al (2015) paper isn't even possible. I attempted to point this out to the "moderator" in comment 815, but look back to this comment and see what happened! Their incompetence in understanding this has resulted in grossly unfair "snipping" of my comments.

    Now, just over the past few days, I had a breakthrough in my understanding of the alleged "rebuttal" to the CO2 band saturation effect. It turns out that most everyone working on this CO2 band saturation issue has religiously applied Kirchoff's Law of Thermal Radiation even though this law applies only to systems in thermal equilibrium, and a warming atmosphere is not in thermal equilibrium. Well, this week I showed that this application of Kirchoff's law implied that there could be no CO2 greenhouse warming without violating energy conservation, and as you can see from the postings, this did not settle very well with several people on this page, especially the moderators. Despite the denials and ridicule, however, no one has disproved me.

    Finally, I should point out that I have reached out in 813 for individuals willing to help me trouble-shoot my approach and identify any misconceptions I may have that renders my methods invalid. To initiate this effort, I posted two questions that I believe should be easily answered, but thus far I got no response. Now, with the arrogance and hostility toward me that they have shown, I believe they would have torn me to pieces if they could. Well, perhaps they can't!

    [snip]

    Moderator Response:

    No, you clearly do not understand any of the objections that have been made. And these have been pointed out repeatedly.

    You need to provide numerical results and an explanation of how you arrived at them. In comment 800, you claimed "I have already done the math". Since then you've just made excuses, and continued to misinterpret and misunderstand much of what you read.

    Final Warning

    Please note that posting comments here at SkS is a privilege, not a right.  This privilege can and will be rescinded if the posting individual continues to treat adherence to the Comments Policy as optional, rather than the mandatory condition of participating in this online forum.

    Moderating this site is a tiresome chore, particularly when commentators repeatedly submit offensive, off-topic posts or intentionally misleading comments and graphics or simply make things up. We really appreciate people's cooperation in abiding by the Comments Policy, which is largely responsible for the quality of this site.
     
    Finally, please understand that moderation policies are not open for discussion.  If you find yourself incapable of abiding by these common set of rules that everyone else observes, then a change of venues is in the offing.

    Please take the time to review the policy and ensure future comments are in full compliance with it.  Thanks for your understanding and compliance in this matter, as no further warnings shall be given.

  47. CO2 effect is saturated

    Bob_Loblaw @786

    If CallItAsItIs wants to continue to ignore Kirchoff's law when forming his arguments, he will need to provide a much stronger argument as to why it does not apply than to hand-wave it away with a statement such as "may well be compromised".

    Would violating energy conservation be a strong enough argument for you?  As Charlie_Brown as well as myself have already pointed out, Kirchoff's does not apply in non-equilibrium systems, and that includes LTE along with any system that is warming or cooling.

    Moderator Response:

    Another comment that fails to provide the requested numerical results of CallItASItIs's "theory" of atmospheric energy transfer.

  48. CO2 effect is saturated

    CallItAsItIs @813,
    I'm not sure where you are going with this yea-or-nay stuff, mainly because it is all rather trivial.

    The Schwartzschild equation dIλ/ds = nσλ[Bλ(t)-Iλ] tells us the spectral intensity Iλ at a temperature t will tend to the value determined by the Planck function Bλ(t), this a function of temperature t and familiar to us as the black body curve when plotted for the full spectrum.
    Thus, up towards the TOA, where the atmosphere becomes thin enough to allow IR in the 15 micron waveband to shoot off into space (and CO2 is well mixed way above), there will be altitudes with particular temperatures which define the emissions of a particular wavelength in that 15 micron waveband.
    Earth IR spectrum
    This is why the IR spectrim from Earth is often annotated with blaclbody curves for differing emitting temperatures, these showing CO2 is blocking emissions through much of the 15 micron waveband below an altitude with temperature roughly 220K. Note the spike in the centre of the 15 micron waveband. This spike shows the population of more static non-spinning CO2 molecules (so n in Schwarzchild but not in Planck is greater) sees more 'blockage' such that the emissions to space occur above the tropopause where temperatures begin to rise again. The same phenomenon is seen in the 9.6 micron ozone waveband.

  49. Philippe Chantreau at 06:37 AM on 5 December 2024
    CO2 effect is saturated

    The Feldman et al (2015) paper, published in Nature, shows the values obtained from modeling based on radiative transfer physics (which do not belong to anybody and can't be called "mine" or "theirs"), and it shows how that compares to actual measurements. They match.

    If CallItAsItIs argument is that everyone else gets the physics wrong, then the following questions arise:

    How do the "wrong" physics led to theoretically predicted values confirmed by measurements?

    Can we have references to papers published in serious journals that outline these correct, more complete physics?

    Are there LBLRTMs that integrate these "different' physics and produce usable results, the kind that the USAF would trust in their IR weapon guidance and other systems (like with MODTRAN and HITRAN)?

    What is producing the increased downwelling IR radiation?

    Without answers to these, I'm skeptical.

  50. Sabin 33 #5 - Is solar energy worse for the climate than burning fossil fuels?

    This is a very important summary of information and extremely useful, but I think certain points need more emphasis or examination: First I think it ought to be emphasized that the co2 advantage of solar pvs and the other renewable tech is based on current average use of fossil energy to make them, a part of their current embodied footprint. If these energy sources become renewable, say PVs, then the advantage grows. In fact, all renewable equipment makers should be using their own or others' renewable equipment to make more of them- a zero carbon bootstrap. To make this bootstrap complete the renewables makers need to iron out fossil fuel use down their whole supply chain.

    Second, the statement below from the last reference posted above needs examination: "in addition to having smaller greenhouse gas emissions, solar power likewise outperforms fossil fuels in minimizing direct heat emissions. A 2019 Stanford publication notes that, for solar PV and CSP, net heat emissions are in fact negative, because these technologies “reduce sunlight to the surface by converting it to electricity,” ultimately cooling “the ground or a building below the PV panels.”4 The study found that rooftop and utility-scale solar PV have heat emissions equivalent to negative 2.2 g-CO2e/kWh-electricity, compared to the positive heat emissions associated with natural gas, nuclear, coal, and biomass."

    This statement is true in certain circumstances and not in others. In the case of PVs in the desert in Arizona, the blackness of the collectors absorbs more sunlight than the desert would absorb. It isn't as reflective as snow, but the difference is significant. Of the absorbed sunlight today's PVs convert about 20% to electricity. The other 80% heats the PVs and is either radiated to the sky and ground or convected to the air. This could lead to a net addition to solar input to the climate energy balance at such a site. If the PVs replace grass or trees, the reflectivity issue more or less goes away but so does the latter's co2 trapping. This is however still in favor of PVs with respect to carbon balance, as another of your posts makes clear. In the case of PVs on buildings, the provided shade lowers air conditioning loads which is a clear advantage along with generating carbon free energy, and the reflectivity for most roofs is low. If the roof is highly reflective before PVs are installed, a part of the advantage is lost.

    I think the last of your linked references is wrong in part. There we find:

    "Use solar panels with reflective coatings. These coatings can help to reflect sunlight away from the panels, reducing
    heat absorption.
    Plant vegetation around solar panels. Vegetation can help to shade the panels and keep them cool." The first point, unless it means use selective surface coatings that reflect IR solar wavelengths the the PV can't convert to electricity, makes no sense. The second makes no sense. If the vegetation shades the panels the panels lose access to sunlight. For maximum benefit the panels need unrestricted access to sunlight.

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