Discussion > An invitation to BH Regulars to tear apart my beliefes about CO2
To explain it further, the tropics, where I live for part of the year, has lots of water vapour and the temperature drops by only a few degrees in the night, what's more it doesn't rise by more than a few degrees in the heat of the sun. My guess is that the water vapour is the control knob, acting as a blanket in the night time and reflecting the sunlight in the daytime. But it's only a guess and I don't know of anything in the scientific literature that discusses the phenomenon.
Over deserts however the temperature can drop 30C overnight, and come back up by 30C the next day. There is no, or very little water vapour over a desert.
So why does one very hot place have a diurnal temperature range of 30C and another have a diurnal temperature range of a few degrees, when both have the same amount of CO2? Or do they?
geronimo
Phase change of water, geronimo. Apart from cloud&radiative effects, evaporation/condensation acts as a 'thermal buffer' to ameliorate temperatures in areas of high (absolute) humidity.
michael hart
May 14, 2014 at 8:22 AM | Unregistered Commenter geronimo
Of course it is possible to tell the truth all the time; it is a matter of being able and willing to take the consequences of telling the truth. Lying or withholding the truth are not ways that I am willing to take in order to reach my desired objective.
Yes if my wife wears something that makes her ass look huge or perhaps correctly shows that in fact her ass is getting rather big then I tell her straight (very gently and caringly and always having an escape route in mind ^.^).
I think she values the fact that I am always honest.
Dung
I think Martin A's topic about temperature change in deserts and a comparison with say jungles is a really good point. It begs the question that IF CO2 is a catalyst that causes water vapour to be produced when temperature increases, then why indeed is there no water vapour in the desert as the massive diurnal warming takes place?
Dung
Er Dung, I think that is geronimo's point, not mine.
Martin A
Dung
To generate atmospheric water vapour or clouds you need surface water, open or from moist soils. There is very little surface water in a desert.
Remember too that water vapour or clouds play a much larger role in diurnal heat retention than CO2 . The highest surface temperatures can occur in humid climates such as India.
Entropic man
EM I'm quite willing to be educated but you're still missing the point. It really doesn't matter what causes water vapour, what matters is how the climate reacts to areas of the world where there is no water vapour and CO2 and areas where there is water vapour and CO2. Simply put, where there is water vapour and CO2 there is little diurnal temperature change, and the night temperatures are near the daytime temperatures, and where there is no water vapour and CO2 there are large swings in diurnal temperatures, and the night temperatures freeze your bollard off, which means, if you think about it, that CO2 doesn't seem to trap heat as much as we're told.
geronimo
My apologies to geronimo and I still think it is a great point ^.^
I do not remember there being any caveats in the feedbacks theory?
Co2 causes warming and that warming causes increases in water vapour which then causes even more warming?
17 years of increasing CO2 and no warming therefore no increase in water vapour and no even greater warming.
It sounds like other factors cause warming which causes an increase in water vapour which may or may not cause further warming, CO2 does not seem to have a role to play and as in the ice core records; it is mostly a function of the initial warming (apart from our own meagre contribution).
Dung
Welcome back EM.
Still in the habit of stating the obvious as if it were a revelation of profundity?
"To generate atmospheric water vapour or clouds you need surface water, open or from moist soils. There is very little surface water in a desert."
Martin A
Does anyone see a similarity between gagging Bengtsson (because his comments were not helpful to the cause) and trying to get people on this blog to avoid talking about CO2 not causing warming ?
Dung
yes
Martin A
Martin A
The obvious seems to have been overlooked.
Climate sensitivity is made up of 1.2C/doubling of direct forcing by increased CO2, plus a similar amount of secondary forcing, mostly from increased atmospheric water content.
In the very dry conditions of a hot desert only the primary forcing will show locally, giving a rate of warming half that expected worldwide. Given an increase of 40% in CO2 this would warm the desert by a 0.3C day and night.
I doubt that dung or Geronimo would perceive a shift in mean temperature of 0.3C, when the diurnal variation is 30C.
Entropic man
Does anyone see a similarity between gagging Bengtsson (because his comments were not helpful to the cause) and trying to get people on this blog to avoid talking about CO2 not causing warming ?
Most definitely and I could link to just that coming from other commenters. However, our host has made it clear that he does not want that subject on the main posts as he sees it as disruptive of them. He does, however, tolerate it under 'Discussion' as we see here. And very interesting it is too.
ssat
Hello EM,
I ought to let Dung and geronimo say what they are saying and how I think that what your explanation misses the point. But, if I have understood what they are saying it is this: Comparing the evidence of our senses in a desert and in humid tropical places, and comparing the difference between day and night, it seems pretty obvious that CO2 can't be doing what it is cracked up to do, and that atmospheric H20 has a far greater effect.
I'm pretty sure they are not talking about detecting global warming with their senses - after all, it can't be detected even with a worldwide network of measuring stations.
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"Climate sensitivity is made up of 1.2C/doubling of direct forcing by increased CO2, plus a similar amount of secondary forcing, mostly from increased atmospheric water content."
Is that any better than a guess? Rather than look for 'the missing heat', I'd have thought it would be better for climate science to admit that 'the pause' is nature's way of saying that the notion of 'forcing' and/or the values estimated for it are perhaps erroneous.
It's perhaps not directly relevant but here are some words on my views on 'forcing' etc:
As an ultra-sceptic (about just about everything, not just climate science), it's my nature to disbelieve anything that cannot be verified by tests and observations or by logic. (When I say "disbelieve" I mean not to accept that it is necessarily true; not immediately to believe the exact opposite.)
'Forcing' seems to me to be a fabricated concept, with, at best, some plausibility that it possibly means something as an approximation - but which can only exist in computer models, being incapable of being observed or measured in reality. (If you think otherwise, please point to measurements that verify the concept as it operates; I'm not talking about measuring CO2's absorption spectrum.).
The idea that there is 'primary' forcing (CO2) and 'secondary' forcing (H2)) seems nonsense to me. Both atmospheric CO2 and H20 depend on atmospheric conditions in a complicated and essentially unknown fashion (and the CO2 and H20 levels interact nonlinearly with each other - admittedly the timescales of their variations differ by orders of magnitude). The idea that everything is set by the prevailing CO2 level, that being set by mankind's activities, seems to me to be a climate science fantasy which common sense and the theory of dynamic equilibria say just cannot be right. The idea that one is independent 'forcing' - like the input to a control system - and the others are 'feedbacks', like the feedback signals in a linear control system, to me seems like a gross oversimplification of the nonlinear interactions between everything that occur in reality in the world and its atmosphere.
Martin A
Martin A
How about downwelling radiation?
If the peak at 15 micrometres is not due to reradiation by CO2 your better alternative explaination should be interesting.
http://agwobserver.files.wordpress.com/2010/03/ellingson_1996_fig3.gif
Entropic man
Like everybody else I find it interesting to read new papers which try to understand/explain how and why our climate changes. Most of these papers are pure theory (which does not mean they are wrong of course) and so why are we so interested in accepting them as relevant in discussions about climate change and what to do about it?
Lets look at the main story of the last few days ; Bengtsson. Why are we interested in this story? It is certainly the case that our opposition seem incapable of tolerating any paper/scientist that argues against their consensus. However it is just another paper about a model??
Is Bishop Hill as before simply backing a paper because it disagrees with the consensus?
Does this paper really deserve to be treated as credible if it is based on a model?
However you dress it up or try to complicate it, the scientific argument is simply 'Does rising CO2 cause rising temperature?' That is all it is and feedbacks are simply a possible explanation of how/why. I wonder why we spend so much time discussing distractions?
As geronimo rightly bangs on about; there is a totally separate (but linked) problem about the politics and how we deal with it.
Dung
EM - when I said "it seems pretty obvious that CO2 can't be doing what it is cracked up to do", I should have foreseen that it could be interpreted the way you have. I was not going MyDog'sGotNoNose and saying that CO2 does not in fact absorb and re-radiate electromagnetic energy (if that's what it is that MDGNN is always banging on about).
If I had said "it seems pretty obvious that CO2 can't be doing what it is cracked up to do to the extent that is commonly assumed", perhaps that have been better?
It's true that it would be revealing to compare the spectrum of downwelling radiation at midnight in the desert to the spectrum of downwelling radiation at midnight in New Orleans in mid summer. That might provide the answer. Could you help track down such spectra?
Martin A
Thanks Martin A you're spot on. This incarnation of EM is so thick that I'm beginning to think it's Chandra in disguise.
(or is it Chandra) CO2 absorbs and re-radiates in the 4 and 15 micron frequencies. Water on the other hand absorbs and re-radiates in a number of small frequencies under 20 microns, but above 20 microns it absorbs and re-radiates at every frequency up to 70 microns (I think, going from memory). (I haven't the slightest doubt that the climate scientists have spotted this and have a readily handy explanation as to why heat reflected at 50 million discreet frequencies counts for shit compared to heat reflected at 15 microns).
This led me to speculate on water vapour, or lack thereof, in the desert, and the presence in water vapour in the tropics and the dramatic FALL in temperature during the night in the desert, and the near constancy of temperature during the night in the tropics, and what could cause that massive, as you say 25-28C difference in diurnal temperatures. It certainly looks that in the absence of water vapour the heat retained by CO2 on it's own is negligible, as you say 0.3C of the 25-28C retained in the tropics is down to CO2. (I have no doubt that climate scientists have noticed this and have a perfectly reasonable explanation as to why the desert has a diurnal shift in temperatures 12-15 times those in the tropics, and that it will have nothing to do with CO2). But I was just wondering is all.
I make no claims about this, it's just that enemy of climate science, an "observation".
geronimo
Yes - I wondered if it was Chandra who was wearing an EM mask. But Chandra would not have come up with a spectrum graph, so undoubtedly it's EM. He's certainly doing a good impression of being thick but it's most likely that he's just not paying attention. I think he said he had some distractions to deal with so that might explain it.
Martin A
EM, you say " an increase of 40% in CO2 this would warm the desert by a 0.3C day and night". However, my speculation to Martin's question about what would happen if all of the CO2 instantly disappeared was "I would expect diurnal surface temperatures across the planet to be virtually unaffected apart from deserts, which would become marginally hotter by day and colder by night. The effect on the average surface temperature of the planet would be negligible"
Now, bear in mind that surface temperatures in deserts are HOTTER than those in the tropics by day (as well as colder by night). If CO2 is a powerful greenhouse gas we could assume that its effects are similar to those of water vapour, in other words that flooding the deserts with CO2 would produce effects similar to those in the tropics - warmer by night but COLDER by day? Or is this over simplistic in that it ignores the different absorption spectra of H20 and CO2?
A lot of this argument is obscured by the fact that the climatologist's metric of choice is AVERAGE surface temperature. As Rhoda has said, a benign average surface temperature could kill everyone on the planet.
However, my main point remains that desert temperatures do not appear to have altered during the instrumental record, while CO2 has increased by 40%. Therefore, CO2 is having little or no effect on surface temperatures in the absence of water.
Your comments, and those of others, appreciated.
Roger Longstaff
EM: "How about downwelling radiation?"
You would think that standing in a desert at night while pointing an instrument at the sky and saying to yourself "that's where the heat is coming from" while temperatures around you are falling might suggest that you are missing something.
ssat
"However, my main point remains that desert temperatures do not appear to have altered during the instrumental record, while CO2 has increased by 40%. Therefore, CO2 is having little or no effect on surface temperatures in the absence of water."
If as you say Roger desert temperatures haven't changed with 40% increase of CO2, there isn't much to comment on as it disproves the theory in a very straightforward manner. Just on a more local level a few sunny days and cloudy nights that keep nighttime temps say 10 degrees higher for a while immediately disappears into space on a clear crisp night.
One thing that gets me is that any average global temperature lower than a previous one (say 2 decades ago) immediately tells you that no energy has been stored up in the atmosphere, and you then have to start introducing the 'well, its stored in the ocean now".
a) There just isn't effective physical mechanism to get it there and b) the ocean is absolutely flippin' enormous - any energy that does end up there is basically irrelevant. It looks like there are yearly/decadal and much longer cycles which are based on the ocean which is physically very believable - but to say someone's extra CO2 emissions from driving their Ford Escort to work and back then helps to heat up the 1.3 billion cubic kiliometres of ocean (according to Wikipedia - so every 5 people on the planet get and entire cubic kilometre) is just ridiculous.
Rob Burton
That has made me think about the GCM's
If say we have a model that has say a 0.5 degree increase per decade due to increased CO2 but has significant 'natural variability'. Say it stars in 2000 and wobbles around and ends up with the same 'average global temp' in 2010 as it did in 2000. Is there anything in the model state that helps it get back to it's otherwise linear trend from 2000 or is it equally valid to start a new trend again in 2010.
It would be interesting to hear what state change could get it back on it's original track. I'm sure anything thing like atmosphere <-> ocean energy exchange is just parameterised so I don't expect anything physical to be going on there.
Rob Burton
"... it disproves the theory in a very straightforward manner"
Thank you Rob. Any other comments?
Roger Longstaff
EM. We're talking about diurnal temperatures and the seeming lack of a "blanket" in areas of the world with the same CO2 but vastly different water vapor cover.