Mayan ruins in Guatemala.
This is an email I recently received from statistician Dr. Richard Mackey who writes:
The following appeared on Gore’s blog of Nov 19, 2008:
Looking Back to Look Forward November 19, 2008 : 3:04 PM
A new study suggests the Mayan civilization might have collapsed due to environmental disasters:
These models suggest that as ecosystems were destroyed by mismanagement or were transformed by global climatic shifts, the depletion of agricultural and wild foods eventually contributed to the failure of the Maya sociopolitical system,’ writes environmental archaeologist Kitty Emery of the Florida Museum of Natural History in the current Human Ecology journal.
As we move towards solving the climate crisis, we need to remember the consequences to civilizations that refused to take environmental concerns seriously.
If you haven’t read already read it, take a look at Jared Diamond’s book, Collapse.”
This is a most curious reference.
It means that Gore is advocating the abandonment of the IPCC doctrine and barracking for the study and understanding of climate dynamics that ignores totally the IPCC/AWG doctrine and focuses on all the other variables, especially how climate dynamics are driven by atmospheric/oceanic oscillations, the natural internal dynamics of the climate system and the role of the Sun in climate dynamics.
Brian Fagan in Floods, Famines and Emperors El Nino and the fate of civilisations Basic Books 1999, shows that the Maya collapse, whilst having complex political, sociological, technological and ecological factors, was largely driven by the natural atmospheric/oceanic oscillations of ENSO and NAO. The book is one of three by Brian Fagan, Prof of Anthropology UC Santa Barbara, that documents how natural climate variations, ultimately driven by solar activity, have given rise to the catastrophic collapse of civilisations. The book has a chapter on the Mayan civilisation which collapsed around 800 to 900 AD.
Here are some quotes from his book:
“The “Classic Maya collapse” is one of the great controversies of
archaeology, but there is little doubt that droughts, fuelled in part
by El Nino, played an important role.”
“The droughts that afflicted the Maya in the eighth and ninth
centuries resulted from complex, still little understood atmosphere-
ocean interactions, including El Nino events and major decadal shifts
in the North Atlantic Oscillation, as well as two or three decade-long
variations in rainfall over many centuries.”
“Why did the Maya civilisation suddenly come apart? Everyone who
studies the Classic Maya collapse agrees that it was brought on by a
combination of ecological, political, and sociological factors.”
“When the great droughts of the eighth and ninth centuries came, Maya
civilisation everywhere was under increasing stress.”
“The drought was the final straw.”
“The collapse did not come without turmoil and war.”
Brian Fagan describes how the ruling class (the kings had divine powers, they were also shamans and there was a vast aristocracy and their fellow-travellers that the tightly regulated workers toiled to maintain) encouraged population growth beyond what the land could carry; how the rulers enforced rigid farming practices which were supposed to increase food production and the ruler’s incomes but had the effect of undermining farm productivity and diminishing the quality of the poor soils of the area. When there were heavy rains the soil was washed away. In times of drought the soil blew away.
More quotes from Brian Fagan:
“The Maya collapse is a cautionary tale in the dangers of using
technology and people power to expand the carrying capacity of
tropical environments.”
“Atmospheric circulation changes far from the Maya homeland delivered
the coup de grace to rulers no longer able to control their own
destinies because they had exhausted their environmental options in an
endless quest for power and prestige.”
Gore says that we should use our understanding of the Maya collapse help us solve the climate crisis, noting that “we need to remember the consequences to civilizations that refused to take environmental
concerns seriously”.
Given what we know of the Maya collapse, what is Gore really saying?
He is saying that we should take all the IPCC/AWG publications and related papers to the tip and bury them there and put all our efforts into the study and understanding of the reasons for climate dynamics that address every theory except that of IPCC/AWG doctrine.
Specifically, we should understand as well as we can how climate dynamics are driven by atmospheric/oceanic oscillations, the natural internal dynamics of the climate system and the role of the Sun in climate dynamics.
In an overview of his work Brian Fagan concluded: “The whole course of civilisation … may be seen as a process of trading up on the scale of vulnerability”. (Fagan (2004, page xv)).
We are now, as a global community, very high up on that scale.
Allow me to quote a little from my Rhodes Fairbridge paper because of its relevance to Brian Fagan’s work and what Gore is really trying to say, but can’t quite find the right words.
(My paper is here: http://www.griffith.edu.au/conference/ics2007/pdf/ICS176.pdf ).
“In his many publications (for example, NORTH (2005)), Douglass North stresses that if the issues with which we are concerned, such as global warming and the global commons, belong in a world of continuous change (that is, a non-ergodic world), then we face a set of problems that become exceedingly complex. North stresses that our capacity to deal effectively with uncertainty is essential to our succeeding in a
non-ergodic world. History shows that regional effects of climate change are highly variable and that the pattern of change is highly variable. An extremely cold (or hot) year can be followed by extremely hot (or cold) year. Warming and cooling will be beneficial for some regions and catastrophic for others. Brian Fagan has documented in detail relationships between the large-scale and
generally periodic changes in climate and the rise and fall of civilisations, cultures and societies since the dawn of history. The thesis to which Rhodes Fairbridge devoted much of his life is that the
sun, through its relationships with the solar system, is largely responsible for these changes and that we are now on the cusp of one of the major changes that feature in the planet’s history. As
Douglass North showed, the main responsibility of governments in managing the impact of the potentially catastrophic events that arise in a non-ergodic world is to mange society’s response to them so as to
enable the society to adapt as efficiently as possible to them.
Amongst other things, this would mean being better able to anticipate and manage our response to climate change, to minimise suffering and maximise benefits and the efficiency of our adaptation to a climate that is ever-changing – sometimes catastrophically – but generally predictable within bounds of uncertainty that statisticians can estimate. At the very least, this requires that the scientific community acts on the wise counsel of Rhodes W Fairbridge and presents governments with advice that has regard to the entire field of planetary-lunar-solar dynamics, including gravitational dynamics.
This field has to be understood so that the dynamics of terrestrial climate can be understood.
References:
North, D. C., 2005. Understanding the Process of Economic Change
Princeton University Press.
Fagan, B., 2004. The Long Summer. How Climate Changed Civilization.
Basic Books.”
Robert Austin–
Some of what you write is correct. But you are mistaken on some points.
At least some, if not the majority, of assumed positive feedbacks have a firm basis in physic. For example, the fact that warm air holds more moisture than cold air is not derived from the supposition that recent warming is due to man. (Certainly, no one sizing a dehumidifier thinks this assumption arises from the supposition that recent warming is due to man.) Also, the spectral properties of CO2 or H2O are not derived from the supposition that recent warming was due to man. ( That’s why Phil’s discussion of the behavior or lasers above applies. The spectral properties of CO2 are the spectral properties of CO2.)
That said: There are many parameterizations (aka. approximate descriptions of physics) in models, and these parameterizatoins are often not tightly constrained by known physics. There is enough that is unknown to permit one to doubt predictions or projections of models. At a minimum, the standard should be: provide quantitative compare the predictions with a critical eye describing flaws or strengths in a balanced way.
The difficulty is that, for some reason, quite a few people seem to want to criticize those aspects of the science on which there is greatest agreement: the radiative physics of CO2 and/or H20. Unlike Leif, I don’t know how much the temperature would drop if we halved CO2– but we both agree it would drop. CO2 matters enough that doubling or half, should, in the long run, make a noticeable difference to the earth’s climate. Of course, noticable is not necessarily catastrophic– but that possiblity can’t be excluded either.
Monocausal accounts of the rise and fall of civilizations are surely woefully inadequate
It ain’t necessarily so,
It ain’t necessarily so.
There ain’t no reliance on climatic science
As far as all honest men know.
Phil.
There is a lot of fuzzy logic in this:
“That’s exactly what happens, during the radiative lifetime of the excited state it will endure ~10^5 collisions, more than enough to deactivate the excited state and share the energy with the colliders, predominantly N2 & O2.”
What exactly do you mean by “deactivate” in quantum mechanical terms?
The GHG is in an excited state, pregnant with a photon of a specific energy, a quantum. It cannot give up that energy by rubbing or bouncing against other molecules. That energy will be given off piecemeal. That is what a quantized state means. Thus I cannot see what the collisions have to do with the case.
The infrared photon coming out of the GHG in deactivation will be of the same energy it came in and the only mechanism I see of giving kinetic energy to other molecules is by successive compton scatterings after it comes out.
I read the link you provided: http://www.laserk.com/newsletters/whiteTHE.html
It elaborates a bit more but in no way it makes clear how a quantum state becomes a classical collisions case.
I think that in the AGW models there is confusion between quantum and classical quantities and properties. This is one of them.
Lucia
The sensitivity of a black-body earth is 0.21 K/(W/m2)
The sensitivity of the grey-body earth as we observe it today is 0.30 K/(W/m2). The difference from what I understand is mainly caused by water in it’s various forms, a few other ghgs and surface reflectance. If the insolation increased by 3.7 W/m2 the temperature would rise 1.1 degree C because the 0.30 sensitivity is that of equilibrium, after all the feedbacks, and the minor change of 1.1 degree (compared to the 33 degree already there) can not change the sensitivity much.
Why then will 3,7 W from a CO2 doubling be totally different, giving a 3 degree rise? (IPCC)
Not through feedbacks, the 0.30 K/(W/m2) is what we are observing, with feedbacks included.
Leif says:
Thank you for reminding me that I should not elide important parts of the argument.
Lucia says:
Lucia, how much weight should we give to that possibility, and how much comfort can we derive from that fact that it hasn’t happened in the past. See for example:
Carbon levels in the past where there is evidence of CO2 levels being something of the order of 5 times todays levels (ie 2 doublings) only some 300MYA …
Given that we have evidence that higher CO2 levels are not going to cause the thermal runaway that the AGWers claim, I think that their extraordinary claims require extraordinary evidence, not arm waving, and ten more years of research, during which time I believe we will get a definitive answer, is not going to cause even one doubling in CO2 by man’s hand.
anna v (12:12:32) :
Phil.
There is a lot of fuzzy logic in this:
No fuzzy logic on my part, some misunderstandings about quantum mech. on your part though.
“That’s exactly what happens, during the radiative lifetime of the excited state it will endure ~10^5 collisions, more than enough to deactivate the excited state and share the energy with the colliders, predominantly N2 & O2.”
What exactly do you mean by “deactivate” in quantum mechanical terms?
The GHG is in an excited state, pregnant with a photon of a specific energy, a quantum. It cannot give up that energy by rubbing or bouncing against other molecules. That energy will be given off piecemeal. That is what a quantized state means. Thus I cannot see what the collisions have to do with the case.
The infrared photon excites a transition from a lower rovibronic state (v=0, j=n) to a higher state (v=1, ∆j=0,±1), that takes a single quantum of light. However, there are many intervening rotational states with a small energy separation compared with the 667 cm-1 vibrational separation, so collisions can deactivate one quantum of rotational energy at a time (there are no selection rules for this process). Think of it as jumping onto a second story and climbing back down a ladder on step at a time.
The infrared photon coming out of the GHG in deactivation will be of the same energy it came in and the only mechanism I see of giving kinetic energy to other molecules is by successive compton scatterings after it comes out.
See above.
I read the link you provided: http://www.laserk.com/newsletters/whiteTHE.html
It elaborates a bit more but in no way it makes clear how a quantum state becomes a classical collisions case.
I think that in the AGW models there is confusion between quantum and classical quantities and properties. This is one of them.
Not on my part!
Leif Svalgaard (20:15:06) :
It’s actually pretty amazing that I thought of the car analogy too. What might be more apt is to consider a glass of water with ice that you are holding as you are driving around. Is everything moving the same? Have you experienced that sensation in your stomach after near free fall like on a roller coaster. Not everything moves together – if they aren’t attached rigidly. The Sun moves due to the planets. The Sun is made of gas and plasma (“liquid” is a simplification) and it all acts accordingly (not uniformly I hypothesize) when changes direction occur.
This is the telling formula for center of mass: xcm = (m1x1 + m2x2 + m3x3 +… )/(m1 + m2 + m3 +… ). The distance of the planetary masses (all other things equal) makes the solar system center of mass move farther from the Sun as the distance of the planetary masses increase from the Sun (unlike tidal forces that weaken over distance). Would not the Sun’s orbit around the barycenter follow Kepler’s laws (even thought they were written for planets around the Sun)?
I find your discussion about center of mass and center of gravity interesting. If you dig in a little further, you’ll find that approximations are made for mathematical simplicity. Every atom attracts every other atom (so yes, I disagree with how you describe it). It makes things easier mathematically when lots of atoms/molecules are in the same approximate place. I haven’t figured out how that adds to this discussion though…
Thanks for your insights and time.
Phi.
The infrared photon excites a transition from a lower rovibronic state (v=0, j=n) to a higher state (v=1, ∆j=0,±1), that takes a single quantum of light. However, there are many intervening rotational states with a small energy separation compared with the 667 cm-1 vibrational separation, so collisions can deactivate one quantum of rotational energy at a time (there are no selection rules for this process). Think of it as jumping onto a second story and climbing back down a ladder on step at a time..
Right, quantum into classical.
I need a link before I can begin thinking it is not hand waving here, preferably with experimental results.
Ok, one flaw in my prev post is that 31% of the 3,7 W increased insolation is reflected so it should be removed from the equation.
But still, the remaining 2.54 W should give a 1.1 K temp increase which gives a sensitivity of 0.43 K/(W/m2) or +1.6 C for a CO2 doubling.
(very close to Lyman et al. 2006 btw)
Alphajuno (21:50:24) :
Have you experienced that sensation in your stomach after near free fall like on a roller coaster.
As long as the free fall is maintained, no force is felt.
This is the telling formula for center of mass: xcm = (m1×1 + m2×2 + m3×3 +… )/(m1 + m2 + m3 +… ). The distance of the planetary masses (all other things equal) makes the solar system center of mass move farther from the Sun as the distance of the planetary masses increase from the Sun (unlike tidal forces that weaken over distance). Would not the Sun’s orbit around the barycenter follow Kepler’s laws (even thought they were written for planets around the Sun)?
Consider a little pea at some distance from the Sun. As you point out, the barycenter moves away from the Sun as the bodies of the solar system increase their distance. So, now move the pea away from the Sun; since there is no limit to how far away you can move the pea, there will be no limit to how far away you can move the barycenter either. All of this has been discussed over and over again before. To get a feeling for the arbitrariness of the barycenter notion, consider this question: Since both the Sun and the Earth orbit the barycenter, will the distance between the Sun and the Earth reflect that motion? or will the distance be unaffected by the barycenter orbits? For simplicity, one may assume that the eccentricity of the Earth’s orbit is zero. If so, the distance between the Sun and the Earth will be constant at all times. Agree?
If you dig in a little further, you’ll find that approximations are made for mathematical simplicity.
No, not at all. Mother Nature does not make any approximations. Astronomers and navigators do not make approximations either, but calculate the positions as close to actuality as humanly possible [important when trying to land a spacecraft on Mars].
Anna V
Right, quantum into classical.
I need a link before I can begin thinking it is not hand waving here, preferably with experimental results.
There is generally much handwaving in Phil.’s posts and he can’t even answer simple questions like “Prove that CO2 in LTE emits no radiation while it absorbs the available IR” (that is what he believes 🙂 ) .
Actually it is not necessary to consider lasers that work in non equilibrium conditions and only mudy waters when it comes to the atmosphere .
The things that happen are rather simple .
Let’s consider only a mixture of N2 and CO2 exposed to IR radiation to avoid strawmen and red herrings that come when adding other molecules , non equilibrium conditions and such .
The behaviour of this mixture will be dominated by only 2 processes .
1) absorption and emission of infrared radiation
2) absorption and emission of kinetic energy by collisions
1)
The first process is quantum mechanical .
N2 having no permanent electrical dipole will negligibly interact with IR radiation (it actually has collision induced dipole so emits and absorbs IR but we’ll neglect this) .
CO2 has 3 vibration modes that present an electrical dipole so will interact with IR and 1 mode that is IR inactive .
The vibration energy levels are of course quantified , therefore CO2 has absorption and emission bands .
For the most important energy levels the mean decay time is in the order of millisecond .
As the CO2 has no permanent electrical dipole , it has no pure rotational transition .
However we have seen above that 3 vibration modes induce an electric dipole , so there will also be rotation lines BETWEEN every 2 vibration lines .
The molecule will therefore absorb and emit photons with energy that corresponds to the difference between 2 vibration lines and 2 rotation lines .
2)
The second process is semi classical .
During collisions between CO2 and N2 following can happen with notations : T = translationnal energy , V = vibrationnal energy , R = rotationnal energy .
T-T transfer which is the classical collision where the molecules exchange only translationnal energy
T-V transfer where CO2 changes its vibrationnal energy (e.g excites or decays) while N2 changes correspondingly its translationnal energy (e.g decreases or increases) .
V-V transfer where CO2 changes its V and N2 changes its V too .
T-R transfer is forbidden because neither CO2 nor N2 has a permanennt dipole
T- V+ R transfer where CO2 changes both its V and R while N2 changes its T . This is actually the general case .
(For more technical details you can consult f.ex “V.Joly , C.Marmignon , P.Jacquet in Aerospace Science and Technology 1999 No5 , “Vibrationnal relaxation of CO2 in a CO2-N2 mixture”)
When our mixture is in LTE (Local Thermodynamic Equilibrium) what is the case up to some 100 km altitude , following is true :
– the mean time between collisions is much shorter than the emission mean time . About 100 000 times less . So the mixture is collision dominated what is precisely the condition for LTE .
– the energy is distributed according to the Planck-Boltzmann law what is the consequence of the great number of collisions that equilibrate T with V and R . The V-V processes are a specific matter that I won’t consider here .
From the 2 results above follows and even if Phil. doesn’t like the idea that
The radiation emitted by the excited CO2 can be described by the Planck and Stephan-Boltzmann black body laws at the local equilibrium temperature
So yes , the CO2 in LTE radiates and radiates exactly as much as is necessary to maintain a constant temperature regardless of all collisional processes that are in themal equilibrium too .
anna v (22:10:35) :
Right, quantum into classical.
I need a link before I can begin thinking it is not hand waving here, preferably with experimental results.
Be my guest, Googling “collisional quenching” should find you plenty to start from. In your case there are so many holes in your knowledge on the subject (10+ orders of magnitude out on radiative lifetime!) that a text book would be more appropriate. Laser Diagnostics for Combustion Temperature and Species (Combustion Science & Technology Book)
by Alan C. Eckbreth would be a good start.
Given all your errors in this thread it would be a good idea if you provided links when you posted, it might save some bandwidth.
‘Liquid Carbon Dioxide Pump delivers high-pressure operation.’
Interesting; but isn’t it still the case that under natural atmospheric pressures, CO2 does not exist in the liquid state?
Thanks for the new word. I must say, barracking is a bit… unusual. I had to obambulate over to my dictionary to find out what it means.
Will we be seeing a lot of this word in the next, say, eight years?
Arthur Glass (07:18:16) :
‘Liquid Carbon Dioxide Pump delivers high-pressure operation.’
Interesting; but isn’t it still the case that under natural atmospheric pressures, CO2 does not exist in the liquid state?
True. I was only pointing out that CO2 can exist as a liquid as can all gases under certain conditions.
Thanks, Tom.
I am out of my field in this.
I can see the semiclassical as a sort of coherent interaction/exchange of very low energy photons between whole molecules exciting vibrational bands. After all the kinetic energy available from collisions is very soft.
Can you clarify for me if, once the CO2 has absorbed a “hard” infrared photon it can get deexcited by a collision? I can see cascade decays spewing out softer photons if the energy levels are there, but can collisions trigger this, which is what Phil is saying?
But then, isn’t the issue that N2 cannot give up its energy by radiation and can only transfer it back to H2O and CO2? And given that it is much more abundant than either of those, they will pretty much absorb as much energy as they can from N2 and radiate it away?
Richard Sharpe (10:05:49) :
But then, isn’t the issue that N2 cannot give up its energy by radiation and can only transfer it back to H2O and CO2? And given that it is much more abundant than either of those, they will pretty much absorb as much energy as they can from N2 and radiate it away?
M. Chrysos et al. Phys. Rev. Lett. vol 100, 133007, 2008 show that a large class of molecules, including CO2, absorbs and scatters light during intermolecular collisions. During a molecular interaction [e.g. collision with N2], a transient ‘supermolecular’ complex arises with its own degrees of freedom [different from those of the constituent molecules]. The net result is that a broader band of frequencies [not available to single molecules] can be absorbed or scattered. They show that these long-range intermolecular interactions are far more important than short-range ones for absorption, in conflict with mainstream assumptions.
anna – I too am out of my depth – and the depth of discourse here is wide 😉
I ran across this paper a while back and one of the warmers dismissed it as it contains a spelling mistake in the first couple of paragraphs (yeah, I know) and comes from a laser guy.
http://icecap.us/images/uploads/ClimateChange_Nicol.pdf
Leif Svalgaard (01:36:36) :
Leif,
Thanks for your continuing dialog. May I suggest that you visit an amusement park on your next vacation?
The pea analogy I think would apply to Pluto but not more massive bodies like the gas giants.
Consider a lever. The fulcrum is the barycenter. As you get farther and farther from the fulcrum, it takes less force to raise the large mass on the other side of the fulcrum. I think this analogy would only apply to bodies orbiting another body. Certainly a distant star does not have the same influence if the star is not gravitationally bound to our Sun.
In order for equilibrium to be maintained for the gas giants, the Sun must move with them (otherwise the universe would be a very chaotic place with no bodies orbiting other bodies). When the Sun moves, it may disrupt its internal equilibrium and the 11ish year solar cycle. There are probably other things going on as well but I would find it hard to believe that a relatively chaotic response (referencing the link to the plot of the Sun’s orbiter around the barycenter due to Jupiter only) to large gas giants causing the Sun to speed up and slow down (or wobble) would have no influence. At some point, the Sun’s innards will get reorganized again and then we’ll start seeing sunspots again. But right now, there may be internal solar chaos due to the Jupiter/Uranus/Neptune alignment. The only other answer we have is “this happens once in a while – solar activity will pick up again soon”. That’s not a very good answer.
Leif Svalgaard (01:36:36) :
Sorry, I should have answered your Earth question a little bit more directly. In a two body system with circular orbits – yes I agree. We don’t have that in the solar system.
Alphajuno (20:52:16)
I think it was Aristotle who said: give me where to stand and I can move the earth. He should have added: and a strong and long enough stick.
The fulcrum is a good analogy of why barycenters are just virtual points:
Think of your fulcrum. Substitute the whole length of it with an (large)elastic material keeping the mass there constant. Will the fulcrum work and raise the other mass?
Why not?
Because it depends on the transfer of the forces, no matter how slight, through the strong bonds of the solid material. The elastic material defuses the forces into distortions.
Thus, for gravity and the motion of the planets to have any strong measurable effect on the sun, the force of gravity should have been much stronger than it is. It is the weakest of the four forces we know .
The only way the planets can affect the sun is through tides, and those of course will be correlated with the barycenter motion, but not caused by it, as the lifting of the mass in your fulcrum is not caused by the barycenter. These tides are very small, order of mm lift as Leif has taught us, to make any difference in what the sun does internally.
The tides of the moon on the earth are much stronger. Did you know that the barycenter of the earth moon system passes underneath us, in the earth? Nothing extra than the normal tides happens, because the barycenter is a virtual point sometimes helpful ( as in the fulcrum, and the design of cars) in calculations and mostly irrelevant.
Walk with somebody down a road, one on each side . There is a barycenter between you walking the middle of the road. A car goes through the barycenter of the two of you. Do you feel anything?
It is the forces, not the virtual constructs that are important.
Alphajuno (21:06:56) :
In a two body system with circular orbits – yes I agree. We don’t have that in the solar system.
A three-body system: Sun, Jupiter, Earth. Still agree? Since the Earth’s orbital eccentricity varies, at some point it could be exactly circular [this is just to make the argument simpler]. Your argument should work even if the orbits were circular. If you don’t think so, then at what eccentricity should it begin to work?
This is the telling formula for center of mass: xcm = (m1×1 + m2×2 + m3×3 +… )/(m1 + m2 + m3 +… ).
Does not involve a fulcrum nor anything gravitationally bound. But if you like, let the pea be in circular orbit. Consider two comets orbiting very close to one another. One has eccentricity 0.999,999,999,999,999 and is therefore gravitationally bound, the other has eccentricity 1.000,000,000,000,001 and is therefore not gravitationally bound. You are suggesting that one would orbit the barycenter and the other one not? The orbits that bodies follow have nothing to do with being ‘bound’. The two comets will see almost exactly the same gravitational field and will travel side by side to a very high degree when within several astronomical units of the Sun. If not close enough for you, throw in some more 999s and 000s, until satisfied.
May I suggest that you visit an amusement park on your next vacation?
I may need it, as it is sad in this day and age to be confronted with such blatant ignorance. Maybe there is something to the notion that the school system has failed the public.