Alert readers will have noticed the fewer-than-normal postings over the last couple of weeks. This is related mostly to pressures associated with real work (remember that we do have day jobs). In my case, it is because of the preparations for the next IPCC assessment and the need for our group to have a functioning and reasonably realistic climate model with which to start the new round of simulations. These all need to be up and running very quickly if we are going to make the early 2010 deadlines.
But, to be frank, there has been another reason. When we started this blog, there was a lot of ground to cover – how climate models worked, the difference between short term noise and long term signal, how the carbon cycle worked, connections between climate change and air quality, aerosol effects, the relevance of paleo-climate, the nature of rapid climate change etc. These things were/are fun to talk about and it was/is easy for us to share our enthusiasm for the science and, more importantly, the scientific process.
However, recently there has been more of a sense that the issues being discussed (in the media or online) have a bit of a groundhog day quality to them. The same nonsense, the same logical fallacies, the same confusions – all seem to be endlessly repeated. The same strawmen are being constructed and demolished as if they were part of a make-work scheme for the building industry attached to the stimulus proposal. Indeed, the enthusiastic recycling of talking points long thought to have been dead and buried has been given a huge boost by the publication of a new book by Ian Plimer who seems to have been collecting them for years. Given the number of simply made–up ‘facts’ in that tome, one soon realises that the concept of an objective reality against which one should measure claims and judge arguments is not something that is universally shared. This is troubling – and although there is certainly a role for some to point out the incoherence of such arguments (which in that case Tim Lambert and Ian Enting are doing very well), it isn’t something that requires much in the way of physical understanding or scientific background. (As an aside this is a good video description of the now-classic Dunning and Kruger papers on how the people who are most wrong are the least able to perceive it).
The Onion had a great piece last week that encapsulates the trajectory of these discussions very well. This will of course be familiar to anyone who has followed a comment thread too far into the weeds, and is one of the main reasons why people with actual, constructive things to add to a discourse get discouraged from wading into wikipedia, blogs or the media. One has to hope that there is the possibility of progress before one engages.
However there is still cause to engage – not out of the hope that the people who make idiotic statements can be educated – but because bystanders deserve to know where better information can be found. Still, it can sometimes be hard to find the enthusiasm. A case in point is a 100+ comment thread criticising my recent book in which it was clear that not a single critic had read a word of it (you can find the thread easily enough if you need to – it’s too stupid to link to). Not only had no-one read it, none of the commenters even seemed to think they needed to – most found it easier to imagine what was contained within and criticise that instead. It is vaguely amusing in a somewhat uncomfortable way.
Communicating with people who won’t open the book, read the blog post or watch the program because they already ‘know’ what must be in it, is tough and probably not worth one’s time. But communication in general is worthwhile and finding ways to get even a few people to turn the page and allow themselves to be engaged by what is actually a fantastic human and scientific story, is something worth a lot of our time.
Along those lines, Randy Olson (a scientist-turned-filmmaker-and-author) has a new book coming out called “Don’t Be Such a Scientist: Talking Substance in an Age of Style” which could potentially be a useful addition to that discussion. There is a nice post over at Chris Mooney’s blog here, though read Bob Grumbine’s comments as well. (For those of you unfamiliar the Bob’s name, he was one of the stalwarts of the Usenet sci.environment discussions back in the ‘old’ days, along with Michael Tobis, Eli Rabett and our own William Connolley. He too has his own blog now).
All of this is really just an introduction to these questions: What is it that you feel needs more explaining? What interesting bits of the science would you like to know more about? Is there really anything new under the contrarian sun that needs addressing? Let us know in the comments and we’ll take a look. Thanks.
Gavin
Re my posts 799, 800, 801 and your comment to 799.
The “maximum-ever” anthropogenic CO2 level of somewhere between 700 ppmv (proven fossil fuel reserves only) and 1,000 ppmv (including optimistically assumed new finds) is pretty hard to refute. There is no way that this could be twice the amount, as you said off the top of your head.
The only open issue is the net impact of feedbacks. The models assume these to be strongly positive. The empirical evidence raises some serious questions, especially concerning clouds, which appear to exert a strongly negative net feedback.
Believe this is where we disagree, not on the maximum anthropogenic CO2 level.
Max
[Response: Recent estimates are up to 2500 GtC (for instance http://en.wikipedia.org/wiki/Methane_clathrate#Reservoir_size), but if you think that’s negligible, go ahead. And by the way, there’s a big difference between saying there are uncertainties in the feedbacks and claiming they can all be ignored. Paleo constaints on climate sensitivity just do not allow for net negative feedback – and we’ve discussed this here a dozen times. There is very little point in discussing it again. – gavin]
Thank you Gavin.
Seeing this “can’t happen” stuff once again is like watching a kid playing with matches in a field of dry grass, convinced that the worst thing he could do would be to set fire to the whole matchbook all at once and burn his fingers, and that the grownups are overcautious.
Max: You’ve also forgotten possible deforestation emissions, natural carbon cycle feedbacks like carbon trapped in permafrost, emissions from cement… oh, and all the non-CO2 gases which also contribute to radiative forcing like N2O, CH4, HFCs, PFCs, SF6, the Montreal gases, NF3…
Meh.
Manacker doesn’t think there’s any evidence that climate change could be a potential problem
http://www.bbc.co.uk/blogs/thereporters/richardblack/2009/06/climate_meltdown_yet_fusion_la.html#P82067053
Also thinks that the PETM is in the future.
A pretty pathetic peripatetic.
Gavin,
I have told you that I do not believe methane hydrates are negligible as a potential future energy source.
I have just shown you that their impact on the total atmospheric CO2 is rather small.
The very optimistic estimates of oil, coal and gas reserves which I used to arrive at the maximum-ever anthropogenic CO2 level of 1,000 ppmv cover all of the anthropogenic CO2 we are likely to ever see.
If you have some better figures, bring them out and back them up.
Max
[Response: I did. If hydrates are 2500 GtC, then by your calculation that adds another ~200 ppm, hardly negligible (though you would need 5 times that to double estimates, so that was a bit of an overstatement – though in my defence earlier estimates did reach 10,000 GtC). But I agree that the point is that there is plenty of carbon sitting around. Your claims about feedback being ignorable is the nonsense, not your estimate of reserves. – gavin]
Patrick 027 says, “…Sometimes the net result of very complex behavior can be described accurately in a greatly simplified description.”
True. And then sometimes it isn’t anywhere close.
manacker (797), good review of the bidding. Like Peter M I have doubts if the log equation holds at, say, 560. Maybe the coefficient/exponent changes or maybe even the log form changes. Unlike Peter I don’t have a problem if the log form still proves to be valid. Nor do I have a problem with the concept of forcing being, say, linear at some base and log at another base. IIRC most if not all of the accepted forcing equations for other GH gases (except maybe H2O) are oddly linear.
Nor can I assert or prove that the current formula is not reasonable at 560ppm or even 1000ppm. I’m just saying that I don’t know and that climate science does not know. Climate science is making a reasonable scientific projection given what it knows (and, BTW, what politically we eventually ought to accept), but the boisterous dogmatic assertions that is unassailably exact is personal belief, not science.
Hi Marcus,
[edit]
Thanks for your post #803.
Yes. I have left out all the other anthropogenic GHGs basically because IPCC tells me that the effect of these is essentially cancelled out by anthropogenic aerosols and land use changes (IPCC SPM 2007, p.4).
Radiative forcing (1750-2005) for CO2 alone is 1.66 W/m^2 and for total net anthropogenic factors it is 1.6 W/m^2, so I have used CO2 alone as an approximation of the total.
You are also correct in pointing out that I left out deforestation emissions. I did this for two reasons: first, they are a relatively small part of the total today (roughly one sixth of the total today at 6 out of 36GtCO2 per year), and I believe that the global pressure that is being applied will result in a reduction of deforestation in tropical nations. In addition, there are significant reforestation programs underway elsewhere, which will essentially offset these emissions in the future.
So the 1,000 ppmv “maximum-ever anthropogenic CO2 level” is valid as an approximate probable upper limit.
Max
manacker Says (26 June 2009 at 7:52 AM):
“The “maximum-ever” anthropogenic CO2 level of somewhere between 700 ppmv (proven fossil fuel reserves only) and 1,000 ppmv (including optimistically assumed new finds) is pretty hard to refute.”
Add to that fossil carbon some part of the maybe 42,000 gigatons of carbon stored in the biosphere*, some of which probably will be released due to dieoff from the climate changes caused by the 1000 ppm CO2 from fossil fuels, and the 30,000 gigatons stored in the ocean, some of which will be released as the temperature warms.
*Numbers from here: http://en.wikipedia.org/wiki/Carbon_cycle so I don’t guarantee them.
“Nor can I assert or prove that the current formula is not reasonable at 560ppm or even 1000ppm. I’m just saying that I don’t know”
Well, that’s right, Rod.
“and that climate science does not know.”
And that’s nor, Rod.
[edit – stop the baiting, or I will simply delete all the post]
So maybe just because YOU don’t know something, doesn’t mean NOBODY knows it either.
Does it.
James
All the conjecture of what will happen to the natural CO2 balance as a result of the anthropogenic atmospheric CO2 increase from pre-industrial 280 ppmv to a maximum-ever level of 1,000 ppmv is exactly that: conjecture.
We don’t have a clue what the response will be on increased plant photosynthesis or on higher phytoplankton absorption due to higher CO2 content in the ocean.
Max
[Response: For some reason, you insist on making unsupportable statements. We do know that the carbon cycle feedbacks are positive – you can see it in the ice cores. Do we have a lot of precision on this? no. But that is a lot different from ‘we don’t have a clue’. – gavin]
Gavin,
The link you cited confirmed that of the 2,500 GtCO2 equivalent only a relatively small portion of the assumed global methane hydrate reserves will be economically viable to recover. I believe my estimate of 4x the amount deemed economically recoverable in the USA is a fair estimate of the total. This represents between 25 and 30 ppmv of additional atmospheric CO2, so is negligible. Even if it were twice this amount, it would still be negligible.
The all-time maximum ever anthropogenic CO2 level remains at around 1,000 ppmv (or 720 ppmv above the “natural” CO2 level of 280 ppmv).
That’s it, Gavin. As they say: “Ain’t no’ mo’.”
Let’s talk about model assumptions versus empirical evidence on cloud and water vapor feedbacks in another exchange.
Max
Gavin — As I pointed out some time ago Max Anacker (manacker) is here to waste your time, IMO.
I did a little googling of Max Anacker and I’d say that David Benson is absolutely correct.
Re: Max: Ok, I can buy the optimistic hope that deforestation will level out and not contribute over the next century.
I think permafrost carbon release is still important. And I think that “cancelling out” the other gases because they currently cancel out with aerosols is a bad idea: 1) aerosols are a short lifetime substance. If we were to hold emissions constant at today’s levels, aerosols would stay constant while N2O and other long-lived gases would continue to grow in concentration. That alone would lead to them no longer canceling out. 2) if we’re being optimistic about deforestation, we might also be optimistic about air quality policy, and therefore project that aerosol emissions will actually _decrease_ by the end of the century, meaning that they would not even cancel out today’s concentrations of non-CO2 gases.
Re: Rod B: “Is 5.35*ln[C/Co] the correct direct forcing math (period) for CO2 or not? What’s your view? Yes or No?”
5.35*ln[C/C0] is an approximation that holds sufficiently well over the relevant range of CO2 concentrations that we will see in the next several centuries (eg, between 200 ppm and 2000 ppm).
At low concentrations, where no absorption peaks are saturated, forcing due to gases is close to linear (in between there’s a square root relationship), and at high concentrations, the increase of radiative forcing due to broadening of current highly saturated peaks (which leads to the log relationship) will be dominated by other, smaller peaks whose continued linear increase is currently too small to matter.
The precise approximation (5.35, etc.) will probably continue to change slightly, both with improved understanding of CO2 line broadening in the upper atmosphere but also due to changes in other gas concentrations.
Max,
David Benson is right. You are here to waste everyone’s time. There is no possibility that you’ll ever change!
Your statement that ” It appears that he believes that the logarithmic function is part of a conspiracy by Lindzen…” is just rubbish. Whether you want to call the curve logarithmic or not, the likely figure for a doubling of CO2 from pre-industrial levels is likely to be around 3 degrees.
But you are right about the behaviour of CO2 at low levels. A better understanding could provide more information on the natural GHE of 33 degs C which is beyond question. I notice that even Roy Spencer had to speak up on his website recently when some of his contrarian allies had been denying even that.
CO2 is a significant contributor to that 33 degC. It would be good if someone could put an figure to it, but even so, it must be obvious to anyone with half a brain that doubling the atmospheric concentration is likely to be extremely dangerous and measures to stop it happening should be given the highest priority.
manacker Says (26 June 2009 at 2:12 PM):
“We don’t have a clue what the response will be on increased plant photosynthesis or on higher phytoplankton absorption due to higher CO2 content in the ocean.”
Wrong. We do have quite a few clues, for instance studies of how carbon uptake varies with temperature and CO2 concentration.
As for the 36,000 gigatons of carbon dissolved in the ocean, if I’m not mistaken the solubility is a simple function of temperature. Raise the temperature, and some of the CO2 comes out of solution – though I’m sure Gavin or someone could provide more detail. (Possibly a topic for a post?)
Mark (810) says, “…just because YOU don’t know something, doesn’t mean NOBODY knows it either.”
I absolutely agree. Also, just because YOU don’t know something, doesn’t mean EVERYBODY else does know it either.
Marcus (815), good summary. I can pretty much go along with most of what you say. My major disagreement is that I would say the “sufficiently well approximation at 2000ppm” has some but little scientific justification — at best it’s a SWAG.
PeterMartin (816) starting a phrase with “it must be obvious to anyone with half a brain” puts it out of the science realm right from the git-go.
I would like to know more about the effects of thermohaline circulation in the Pacific Ocean. What about the upwelling of many(?) sverdrups of deep ocean water in the northern Pacific? What are the mechanisms for the rise of deep ocean waters in the northern Pacific? I have heard deep water in the Pacific is warmed. What causes the warming of deep water in the Pacific? How does it affect sea surface temperatures in the northern Pacific? Does it play a major role in cycles of the Pacific Decadal Oscillation? Does the surface flow have any effect on ENSO? Since we have found that there is significant intra-annual variability of the THC in the Atlantic, what about variability in the Pacific? Perhaps there is too little known about this topic.
Gavin, Reur responses to Max, appended on his posts 798, 801, and 805, you wrote in part:
Thus, you have accused Max three times so far of ignoring feedbacks, apparently based on the final line of his 798 where he wrote:
“…So this tells us that the combustion of all the fossil fuels on this planet will result in a theoretical greenhouse warming of under 2°C (excluding the suggested increase due to net “positive” feedbacks).” (my emphasis added)
However, this should be read in the context of his whole post in which the uncertainties in feedbacks are indicated to not allow, at this time, for reliable adjustment to the underlying CO2 GHG effect. Thus he does NOT ignore feedbacks, and clearly indicates that he has excluded them because of that uncertainty.
In fact, Max has been very active elsewhere discussing for instance the work of Andrew Dessler et al (peer reviewed and published in GRL) that indicates a positive feedback of water vapour within certain constraints. He has also discussed the work of Roy Spencer et al (also peer reviewed and published in the very same journal; GRL) in which a highly significant negative feedback in clouds is indicated, but again within certain restraints. (eg spatially in latitude, as were the limitations with Dessler’s work)
In fact, Max does not ignore feedback, it’s just that there is uncertainty both in magnitude and sign of the various elements of it, and he did not include any guesswork in that respect in his 798, as stated.
[Response: ??? His ‘conclusions’ in #798 only arise if he ignores feedbacks. They can’t be ignored, therefore his ‘conclusion’ is nonsense. – gavin]
Good. About time. Go away until you learn it, too.
Really? You never took any mathematics courses where the teacher says …
“Clearly …”
?
If you understood without explanation, you were on your way. If you didn’t, well, you weren’t.
For Steve Mann — actually it’s well answered already.
I tried pasting your entire multi-question posting above into the Google search box, minus the last sentence.
It works — 31 hits.
Try it! you’ll get links into relevant pages at the AIP and in various topics here at Realclimate.
The same huge search done in Scholar gets 26 relevant papers, mostly recent, mostly with multiple later citations you’ll find helpful.
Google’s apparently able to take _huge_ compound questions and give relevant and useful responses.
Those ought to help you focus without lots of retyping here.
Mark @ 728:
That’s not at all what I said, and I’ve stated that CO2 emissions in one place can be “made up for” with CO2 capture (or conversion to biomass) in another place. If you want to run your vehicles on switch grass ethanol, or algae biodiesel, have at it. My own personal experience with owning an electric vehicle is that it’s really nice not to have to buy fuel from a gas station.
“I absolutely agree. Also, just because YOU don’t know something, doesn’t mean EVERYBODY else does know it either.”
WHAT????
THE????
[edit]?????
How does that follow?
What does it MEAN???
You stated that science doesn’t know something.
Your only proof of this is that you didn’t know it.
Marcus
Thanks for your #815.
Did a quick check on the potential magnitude of the long-term permafrost carbon release with warming.
http://www.sciencedaily.com/releases/2009/05/090527130826.htm
“Schuur noted most of the 13 million square kilometers, or roughly 5 million square miles, of permafrost in Alaska, Canada, Siberia and parts of Europe remain frozen. However, thawing already occurring around its southern edges is expected to expand this century. Should that occur, this study suggests the permafrost could lose in the range of 1 gigaton of carbon, or 1 billion tons, per year – about the same order of magnitude as being added by current deforestation of the tropics, another large biospheric source, Schuur said.”
So it is (maybe, if the plants can’t keep up with added photosynthesis) up to 1 GtC per year (or around 10% of the current 10 GtC per year from fossil fuels, deforestation and cement production).
I would agree with you that it is a substantial amount, but not enough to greatly change the 1,000 ppmv long-term maximum anthropogenic CO2 level.
Max
manacker writes:
Water vapor feedback is “anything but certain?” Why don’t you try Googling “Clausius-Clapeyron law?”
Or read these:
Brown, S., Desai, S., Keihm, S., and C. Ruf, 2007. “Ocean water vapor and cloud burden trends derived from the topex microwave radiometer.” Geoscience and Remote Sensing Symposium. Barcelona, Spain: IGARSS 2007, pp. 886-889.
Dessler AE, Zhang Z, Yang P 2008. “Water-Vapor Climate Feedback Inferred from Climate Variations.” Geophys. Res. Lett. 35, L20704.
Well! How about these five pillars of rational scientific debate, and their most recent wisdoms:
1) Mark 810:
“…So maybe just because YOU don’t know something, doesn’t mean NOBODY knows it either.”
2) David B. Benson 813:
“Gavin — As I pointed out some time ago Max Anacker (manacker) is here to waste your time, IMO.”
3) dhogaza 814:
“I did a little googling of Max Anacker and I’d say that David Benson is absolutely correct.”
4) Peter Martin 816:
[1]“Max, David Benson is right. You are here to waste everyone’s time. There is no possibility that you’ll ever change!…”
[2]“…it must be obvious to anyone with half a brain…”
5) Rod B 818:
“Mark (810) says, “…just because YOU don’t know something, doesn’t mean NOBODY knows it either.”
I absolutely agree. Also, just because YOU don’t know something, doesn’t mean EVERYBODY else does know it either.”
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
To demonstrate what I mean, I COULD respond to Peter Martin’s 816, item [2], in the same fashion that we see commonly from Mark, like this:
“Peter Martin, since it’s a fact that you only have half a brain, that explains your stupid dogma on this matter.”
I would only be joking in such a hypothetical of course, but how does this sort of waste of page-space junk have any benefit in what should be a scientific debate?
BobFJ, how does any of that show what you are trying to insinuate?
Are you saying that if someone doesn’t know something that this MUST mean that nobody else knows it either?
How does saying that someone is wasting your time prove they aren’t wasting your time?
And if Max does have form, isn’t that a FACT OF MEASUREMENT?
You know, like “The CEO of Exxon-Mobil may have a stake in the AGW debate”. Saying so doesn’t make the CEO have no stake in it, does it.
And does telling someone to stop wasting your time mean that you must waste your time?
The Oracle has your number: reuther threeyearolds.
BobFJ, what goes on in the comment thread isn’t a “scientific debate” — that takes place in laboratories, journals, scientific conferences, and the like. What goes on here are discussions and debates and arguments related to the science, by people who are interested in and often (but by no means exclusively) who’ve learned something about the science. So far as I know, none of the five people you’ve quoted are climatologists. If you just want the science, read the part written by the scientists ;)
Gavin, first of all, thankyou for NOT deleting my post 822.
However, you appended a response to my 822 that I must disagree with. You wrote in full:
Sorry Gavin, but you have now accused Max of IGNORING feedbacks for the fourth time, but this is simply not true! Let me repeat what Max said, after him earlier in his text making clear reference to feedbacks and their uncertainties:
So this tells us that the combustion of all the fossil fuels on this planet will result in a theoretical greenhouse warming of under 2°C (excluding the suggested increase due to net “positive” feedbacks). (my emphasis added)
This should be read in the context of him saying that there is a considerable uncertainty in the net of various positive and negative feedbacks.
Of course, he might have avoided pedantic attack by expressing it more concisely such as like this:
“…will result in a theoretical greenhouse warming of under 2°C, plus x, where x = the net of positive and negative feedbacks that are yet to be convincingly determined.
AND, of course, if anyone wants to consign a value to x, then please go ahead!
BTW, do you disagree with the recent study of Roy Spencer et al (negative for clouds) as peer reviewed and published in EQUAL STATUS with Andrew Dessler et al, (positive for water vapour) in the SELF-SAME journal? (and that these do not resolve the uncertainty?)
Do I need to quote AR4 about the IPCC’s confessed uncertainty in 2007?
[Response: ??? You seem to be missing the key quote #798: “As these are all anything but certain based on the empirical evidence supported by actual physical observations, we can probably ignore them for now.” I think I’ve made clear I disagree. Uncertainty does not mean that a value of zero is valid. – gavin]
Max (#799),
I think your numbers on how much carbon man can put into the atmosphere are a gross underestimate because you are using an “economically recoverable” filter which is unreasonable. Presently, we extract fossil fuels as an energy source so that your filter makes some sense. But, there is a clear trend of increased extraction with lower energy payback for fossil fuels so we must question the assumptions in economic recoverability as a limit. This is especially true because it does not much matter when the carbon enters the atmosphere, only that it does. If we have an economy over the next 500 years, it is entirely possible that we might go extract oil from currently abandonded fields at an energy loss so long as the price for oil is high enough. So, for conventional oil alone we should estimate at least another 5 trillion barrels available at a price for oil above $120/barrel (see for example World Energy Outlook 2008). It won’t be available all at once, but that just helps to keep the price high and ensure its eventual production and use. Similarly, for shale oil, you should use something much closer to oil-in-place estimates so that 8 trillion barrels might be used over the next 500 years. Extensive thin coal seams may well sucumb to the automation trend in mining that is already strong in that industry if the price of coal rises much. In situ coal gassification may provide access to deep coal seams as well. One can easily envision a 100% renewable energy economy which uses cheap abundant renewable energy to extract fossil fuels at a net energy loss to allow for such convieniences as aviation. The energy supply would be 100% renewable but we’d be using that energy to cook up that last bits of Green River Formation at near 100% recovery of oil-in-place.
Given these very large corrections, it is a bit a nit to pick to point out that your high estimate of the amount of oil that goes into petrochemicals really does not help us much because much of that will be burned. If we are mining tar sands at an oil price $60/barrel, the asphalt in our roads will soon be replaced with cement as we crack that as well. Weathering would do the job in any case.
There is a very simple road (often called BAU) to a much higher concentration of CO2 in the atmosphere than you assume. It seems to me to be an economically unavoidable outcome unless we do something to control the price of oil and coal and eventually natural gas to assure that resources don’t get exploited. http://mdsolar.blogspot.com/2008/06/oil-is-too-expensive.html
manacker states:
“All the conjecture of what will happen to the natural CO2 balance as a result of the anthropogenic atmospheric CO2 increase from pre-industrial 280 ppmv to a maximum-ever level of 1,000 ppmv is exactly that: conjecture.
We don’t have a clue what the response will be on increased plant photosynthesis or on higher phytoplankton absorption due to higher CO2 content in the ocean.”
100% bovine tail pipe emissions. Not even going to begin citing references that nullify this claim. It might be best for all involved if you don’t confuse what you don’t have a clue about with what scientists don’t have a clue about.
dhogaza, so if a student has no preconceived knowledge of integration by parts, he is clearly not scientific and is out — too bad?
Mark (827), am I still going too fast??
Maybe I’m being unfair as dhogaza didn’t catch it either. You said if I don’t know something doesn’t mean that others don’t know it. And I said that if I don’t know something, that doesn’t mean that others do know it. It’s not complicated. Whether I know something or not has no logical conclusion that anyone else knows that something or not.
“Mark (827), am I still going too fast??
Maybe I’m being unfair as dhogaza didn’t catch it either.”
No, you’re going too stupid.
You;re saying that A=B and B=C therefore C=A.
There are quite a few mistakes there.
Your only “proof” of how science didn’t know it was that you didn’t know it.
See Argument by Personal Incredulity.
Sorry, Max Acker, you keep using the number for instantly doubling CO2 without changing anything else as though it were possible.
You can’t imagine any way to have that happening. Nor the opposite — to _halve_ the number of CO2 molecules without changing anything else.
In your next thought experiment, leap off the floor and hover.
Now, while hovering ….
See? If you weren’t on this planet, you might be somewhere that could work for you.
But here you are.
“Reality is that which, when you stop believing in it, doesn’t go away. ” — Philip K. Dick.
Gavin, you appended the following to my 833
Sorry Gavin, but I think it is unfair that you isolate that line, because e.g. the paragraph that followed it is more key in that it explains context
“As it looks at this point, observed water vapor feedback is a fraction of what would theoretically occur if relative humidity remained constant as assumed by the models and clouds appear to actually exert a fairly strong net negative feedback instead of a strong positive feedback as assumed by the models.”
And, you also wrote:
But Max does not suggest that feedbacks amount to zero net. In effect he says they net to x, where x is currently unknown/not yet understood. He clearly states for his conclusion: [this is] “excluding the suggested increase due to net “positive” feedbacks”
Thus if you or anyone want to vector in an estimated feedback effect, you are free to do so.
Oh, and BTW, my 833 mentions recent peer reviewed work on water vapour and cloud feedbacks, that are very significant to this context. It would be good if you could find time to comment on that.
… MLS and AIRES observations show an increase in cirrus clouds and water vapor over warm oceans, indicating that cloud and water-vapor feedbacks amplify global warming.
— Professor Paul Dimotakis, Engineering & Science, Spring 2009, p. 43.
David B. Benson Reur 841:
This is a quickie, because I have commitments this evening. Your reference to Professor Paul Dimotakis, Engineering & Science, Spring 2009, p. 43. is interesting, but I don’t have access to it. Is there any chance you could expand on it a bit?…. like for example, what are the spatial and temporal limitations, how much, and what are the relationships with other parameters and whatnot. Also what about the low level clouds? What happened there?
Does it contradict the two GRL peer reviewed papers of Andrew Dessler and Roy Spencer?
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Meanwhile, since Gavin has not yet, and may remain too busy/uninterested to respond to my 840, I’m wondering if you may be able to help me with a problem I have with the feedback debate in a seldom mentioned crudely six-cornered interdependence thingy as follows:
1) Water vapour,
2) Cirrus clouds,
3) Other clouds
4) Particulates
5) Evapo transpiration (evaporative cooling)
6) Convection/conduction.
As an engineer, I’m very curious about these six basic interdependencies, but perhaps the most troubling aspect of it is the level of understanding about clouds.
Could I ask you to study the following?
Cloud Feedbacks in the Climate System: A Critical Review.
http://irina.eas.gatech.edu/EAS_spring2006/Stephens2005.pdf
I have some questions.
The IPCC reports goes into that.
I take it you haven’t read it yet.
Do that first.
Use your time before you use others.
re840, Max has picked up someone else’s model (note that: MODEL) that has no science to explain why it happens (note that: NO SCIENCE) and whose figures are fitted to the curve (note that: curve fitting) to make it work over what we’ve measured.
But this is EXACTLY what Max says is wrong about climate science (although he’s wrong that it applies to GCMs).
1) Model, not empirical
2) No science
3) Curve fitting
strange isn’t it.
And you’re fine with those three.
You can get the log curve from the basic science involved.
Therefore it’s a log curve.
Just like you can get PV=nRT from the basic science used in the Ideal Gas Law and this only breaks down when
a) there are very few molecules there
b) there are far, far too many molecules there
and this breakdown of the Ideal Gas Laws is well understood.
Just like the breakdown of the log relationship.
If you think it could be something other than log law, do the work, show the science and don’t do #1-#3 above.
“…crudely six-cornered interdependence thingy” ?? There’s no answer to that!
I think we should let Gavin get on with his report for the IPCC. It sounds slightly more important.
Mark #838.
“You;re saying that A=B and B=C therefore C=A.
There are quite a few mistakes there.”
Sorry, I don’t understand. Please explain.
For the study of Prof. David Rutledge on cumulated carbon contained in our planet’s total fossil fuels see:
http://rutledge.caltech.edu/
My long-term figure of 1,000 ppmv CO2 is shown by Rutledge to be on the high side (he comes up with figures under 450 ppmv, while IPCC puts this at 500 to 980 ppmv by 2100).
Rutledge estimates that this will result in a long-term temperature increase of 0.0 to 0.5°C above the 1998 all-time record (which was 0.515°C above the 1961-1990 baseline, according to the Hadley record).
This equals a total anthropogenic temperature increase (from pre-industrial times) of around 0.9 to 1.4°C from all the fossil fuel on this planet.
Rutledge’s numbers may be a bit on the low side, but I believe they point out clearly that an anthropogenic CO2 level of much above 1,000 ppmv (or 720 ppmv above the “natural” CO2 level) is not realistic.
David B Benson/all,
Further my 842, concerning the interdependence of parameters that make-up individual feedbacks, the most frequently discussed are water vapour and various cloud types. These obviously all require a budget of water vapour, but there are complications. For example, one of them might increase, but would that necessarily be because the total budget has increased or that another has reduced, thus changing the ratios. Or, if there is drought, more water remains suspended and so-on.
Whatever, the underlying driver is evapo-transpiration. (E-T) The 3AR and AR4 WG1 reports (2001/2007) show that (E-T) comprises ~46% of the HEAT loss from the surface, as a consequence of evaporative cooling. This is a huge proportion of HEAT loss from the surface, and the non-EMR, (non-radiative) losses, (that are probably interdependent), total the majority of loss at ~61%, compared with only ~15% via EMR that is absorbed by greenhouse gases.
(Thermals; ~14%, EMR directly to space; ~24%)
Thus, it follows that if water levels in the atmosphere are increased via feedbacks, then the already large cooling effect of ~61% would as source, also have to increase, and that thus there would be major negative feedbacks.
Do you know of any work that discusses or quantifies this?
Do you disagree?
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Data source; e.g. see FAQ 1.1, figure1, extracted here:
http://farm4.static.flickr.com/3178/3064545467_7b7d04b38d_o.gif
BobFJ (842) — The article by Dimotakis is a reply to letters regarding his earlier contribution in E&S. There is nothing more regarding clouds.
I read The Stephens paper you linked. He mentions, but not not begin to use, the systems identification problem (sip) of control theory. There is a vast literature on sip, some of which might be of use in climatology.
833 response by Gavin, “Uncertainty does not mean that a value of zero is valid. – gavin]”
Yet isn’t that exactly what the IPCC does with regard to sea level rise? Since the potentially devastating and certainly not zero rise of sea level due to ice melt over the next several decades is unknown, the whole shebang is ignored in the final estimate.