Open thread for various climate science-related discussions. Suggestions for potential future posts are welcome.
Leo G — About removing the excess carbon from the active carbon cycle: assuming all of us stop using so much fossil fuel, there are several routes to removing the alrady existing excess. One is to bury biochar, possibly charcoal from trees grown just for that purpose, as in
Irrigated afforestation of the Sahara and Australian Outback to end global warming
Another is to enhance chemical weathering as in
In situ peridotite weathering:
A third is to capture CO2 directly from the air and permanently sequester deep undeerground.
None are without cost, but some biochar schemes seem rather inexpensive.
Leo G – “I understand the theory of C atoms absorbing and releasing radiant energy at certain wave lengths. Simple and makes perfect sense. Now the question, since we are talking about CO2, does the chemical bond between the carbon and the oxygens effect this absortion at all?”
It is common practice to measure fluxes of CO2, organic C, carbonate minerals, elemental C (whenever that would be important) in terms of amounts of C because the amounts don’t then need to be converted between different forms.
But the radiative properties of CO2 are not at all the radiative properties of C. The effects of a sooty or graphite-powder filled atmosphere or diamond-dust filled atmosphere would be different from each other and quite different than a gaseous CO2-bearing atmosphere, which itself is at least somewhat different than the effects of dry-ice clouds (dry ice clouds would contribute some albedo but would also contribute to a greenhouse effect via scattering of LW radiation (as well as absorption/emission???)(whereas gaseous CO2 contributes to a greenhouse effect by it’s absorption/emission spectrum) (dry ice clouds may have been important on early Mars).
#1044, Hi Lynn, how we all wish it were as easy to get started on an alternative path as it would have been only twenty years ago…begun forty years back, cakewalk might seem an operative term. Unfortunately the natural positive climate feedbacks have been kicking in all the while we have waited for our better angels. Less ice cover, more melting tundra, eventually potential explosions of a few methane hydrate deposits, saturation of carbon sinks, the recovery of normal solar output, reduction of aerosols aloft due to cleaner technology in China or various economic disasters, increased natural burnings of forests (including cities) and coal seams: the list could go on. The effect is a diminishing return on human climate protection effort of any kind, or conversely a multiplier of human climate protection effort that will be required over time, even as adaptive expenses mount.
I would be interested in a projection by Dr. Hansen et. al. about when natural feedbacks can be expected to marginalize human efforts to mitigate climate change. I remember reading somewhere that natural releases of CO2e recently amounted to 2 billion tonnes per year, which would have been close to 5% of the total anthropogenic GHG emissions in 2005. Many of us had taken literally the “turn of the (21st) Century” idea that only a decadal window remained open to achieve serious reversal of the trajectory of anthropogenic GHG emissions. Recall Michael Jackson’s mention in rehearsal captured for the motion picture “This is it” of the fact “we have four years left,” if I remember his dialog properly.
A fairly straight line logarithmic projection of the global trend in GHG emissions established 1995-2005 which I think may be reasonable based on expected human population growth puts us around 60 billion tonnes anthropogenic GHG emissions per year by mid-century, half again higher than in 1990. How will natural (positive feedback) emissions compare during this period? Doubtless they will increase. But when will natural emissions then outweigh whatever humans can or will do going forward? That point surely is coming. It seems to me, if identifiable, to form the natural endpoint of human mitigation efforts, and marks a full move into utter survival mode for civilization and many human beings. Ironically the more progress humans make at reducing their GHG emissions, the more pronounced will seem the natural feedbacks as they occur.
Perhaps better than any temperature rise by any date certain, the day that natural feedback GHG emissions probabilistically trump human emissions could serve as a meaningful endpoint against which to measure alternatives and options, especially such human processes as urban planning and reconstruction, refugee resettlement and assimilation rates, typical warfare blooms and technology adoption rates.
#1018 Greg GoodKnight
Are you really that thin skinned? As I said, if you are sold on GCR’s explain how they can add 3.6 W/m2 to atmospheric radiative forcing. And show your work.
Please explain why global temps did not jump during the Laschamp event for everyone here.
Also please explain how CO2 is not a greenhouse gas and that adding billions of tons of it to the atmosphere does not increase heat trapping ability.
I’m sure many here would like to see you prove your points so we can all move on. Looking forward to your answers. And by the way saying ‘there are many fine scientists working on this’ is not a proof of any kind. You’ve go t to show how they are correct in contrast to the many well analysis that show that the effect of GCR’s v. industrial GHG’s is more meaningful.
“But the radiative properties of CO2 are not at all the radiative properties of C. ” …
This being most important for longer wavelength radiation (such as that which is involved in the greenhouse effect) that is emitted or absorbed via exiting molecular vibration modes, etc. I’d assume there is considerably less difference among C atoms in different embodiments in the absorption of ionizing radiation involving core electrons.
#1048 Greg GoodKnight
You seem to love to focus on the ‘snide sarcasm’. Sort of a red herring though and truly unimportant. Actually, I think it is funny. I can’t imagine you in a conversation with a bunch of guys talking about GCR’s and solar and making snide remarks about those crazies over at RealClimate.
Now, if you can confirm for al of us here that you don’t make snide remarks in any conversations about those crazy ‘warmists’ that think CO2 is a significant GHG and that other GHG’s have been boosted in the atmosphere by industrial process, then we can canonize you.
As to concentrations. CO2 increase is around 0.01% representing around a 38% increase on mean seasonal fluctuation.
Of course going from 0.028 to 0.038 is a significant change. To call it anything else is to trivialize reality.
To put it in context, without that 0.028 CO2, the earth would be a frozen ball in space… or do you think GCR’s are really what is keeping us warm?
I have to confess that I am shocked by the rudeness of the pro-AGW people on this forum. I can certainly understand your frustration with many of the so-called “skeptics” and I think that when they are being not only wrong but wrong-headed and showing signs of acting in bad faith it is reasonable to be frank in calling this out, but I see people crossing the line here to being nasty, and doing this ultimately really just ends up hurting yourself because it makes it easier for your adversaries to pain you as being unreasonable.
@ Greg Goodknight # 1048
- “Jim Eager (#1041), the number I gave is correct for the metric I was trying to describe in the late hours last night, the fraction of the atmosphere that the increase of CO2 represents, held to one significant digit, but I suspect you already know that.”
Actually, the percentage is more like ~ 0.04% rather than ~ 0.01%, which is a factor of four but admittedly within the same order of magnitude as your figure. More importantly, the fact that this percentage is small is completely irrelevant; what matters is the sensitivity, so if you disagree with the assessment of this sensitivity it would be better to tackle this head on. The problem with tossing out figures like “0.01%” when reflection shows that they they are irrelevant is that they seem to be an appeal to intuition over evidence, “Surely common sense tells us that anything that is only “0.01%” of the atmosphere couldn’t have *that* big of an effect!”
- “If theories and research contrary to the RC wisdom were as weak as RC partisans believe, there should have been no need for the UAE CRU cohort to subvert the review process to kill inconvenient research or to effect removal of editors who weren’t compliant enough.”
That is one interpretation. Another is that the science that they were objecting was actually bad but was being published anyway due to political reasons, in which case they were doing their jobs and should be applauded for their efforts in this regard. Proper context is everything.
Also, frankly one should be careful about seeming to endorse hacking into the e-mail servers of those that you disagree with and using the information gleaned from this — which is inevitably going to be taken out of context — in order to assassinate their characters, if you ever want to be considered to be acting in good faith.
- “Followers of RC dogma are no more moral or intelligent than those who have not swallowed the AGW kool-aid.”
While I agree that many posters have crossed the line from frankness to rudeness in responding to your post, I must frankly point out that including a gratuitous taunt like this in your post is provoking this kind of reaction.
- “Stop denigrating the opposition; everyone who agrees with you are not your friends, and everyone who disagrees with you are not your enemies.”
I completely agree with this sentiment, but given the previous quote it does seem slightly hypocritical.
@ David Wright # 996 – “Apparently the reality of the CRU expose’ has not sunk in.”
Many of you here are objecting to this quote, and I can sympathize with this reaction because personally the CRU hacking is one of the very few things invoked by the anti-AGW side that makes me actively angry.
Having said this, David does have a point. Even when someone is being a crackpot, when you are perceived as not only opposing the crackpot but making active attempts to “squelch” the crackpot so that they can’t be heard at all, then many people will see this as providing evidence that the crackpot actually had a good point all along but is being shut down because those holding the conventional view are afraid of being overthrown even if they are wrong. Even if this characterization is completely unfair, people will still hold it.
@ dhogaza # 1002 – “Go jump off a cliff, David Wright. A high one. Because, after all, Einstein proved that Newton was wrong, therefore, such a jump can’t harm you, can it?”
Again, the CRU scandal personally makes me very angry and so I can sympathize with your reaction, but people who are looking to cast the pro-AGW side as consisting of unreasonable people will point to quotes like this as “proof” that they cannot tolerate any challenge at all, but rather get defensive and rude.
@ simon abingdon # 957 – “We’re just arguing semantics.”
I concur with you on this point. I also must respectfully suggest that you were trying too hard to parse words in your posts. During nighttime, when someone puts a blanket on a person or object to keep it warm, they don’t think “I am going to put a blanket on this in order to prevent it from cooling down,” they usually think “I am going to put a blanket on this to keep it warm,” i.e. that they are using the blanket because of its “warming effect”. It is true that from the standpoint of thermodynamics you aren’t warming anything in this case but rather are slowing down the rate of cooling, but the effect of keeping something warmer than it would be otherwise is still a real effect and is what the term “warming effect” is understood to mean, consistent with colloquial usage.
Greg (@1048), describing CO2 or the increase in CO2 as a fraction of the total atmosphere is known as the dilution argument, which is a red herring distraction since all greenhouse gases combined, including water vapour, constitute less than .5% of the atmosphere, meaning that over 99.5% of the atmosphere is not directly involved in the radiative absorption mechanism of the greenhouse effect. That means the relevant metric is the increase in CO2 compared to other greenhouse gases, not compared to the total atmosphere.
I don’t know if you already know that or not, but as a self-described scientist you certainly should, which suggests that your intended metric was either used out of ignorance or was meant as deliberate distraction or misinformation.
Care to fess up as to which is the case?
Timothy Chase (#999), and Ron R (#966)-
I feel that you could add a patina of erudition to your exchange if it were continued in latin.
Leo G (#1049), in my layman’s understanding,
- being an atom, C has electronic energy transitions with their characteristic absorption/emission lines;
- being a molecule, CO2 has vibrational and rotational energy transitions as well, which correspond to characteristic absorption/emission bands.
Hope this is helpful (and reasonably accurate) for starters.
Climate change sceptics will note that the above latin link allows full inspection of the source code.
I understand stratospheric cooling (more or less). What would one expect specifically in the upper trop/lower strat altiudes (9-15 km, especially at the N pole? As an aside, what causes extreme temp at that altitude (<-60c)? Can we expect more or less of these in the future? (working on an airline freezing fuel problem)
In the programming world they call it dead chicken waving… as in ‘hey, look at me waving my dead chicken’.
Greg GoodKnight is utilizing his superior ability in politeness to prove gcr’s have a significant temperature regulation ability in contrast to CO2 and, and, and…
I would love it if he would provide some substance to his argument. Let’s all be patient with Greg, he will solve it all and prove CO2, CH4, N2O and flourins are not significant to increased radiative forcing, while GCR’s have not been increasing in the past 20 years in step with temperatures, thus proving that relatively stable GCR’s increase temperature on earth and greenhouse gases are insignificant.
We’re waiting, and waiting, and waiting…
Leo, as has already been pointed out by others, it is indeed the quantum mechanics of the carbon-oxygen bonds, particularly the bending mode, that give CO2 its ability to absorb and emit long wave IR photons of discrete wavelengths, particularly centering on 15 microns.
For more help in understanding this I highly recommend David Archer’s Global warming: Understanding the Forecast
the slim text book for his UofChicago science for non-science majors course of the same name.
The best part is all of the lectures for his course are available free on-line at:
About the moderation:
I agree you should be reasonably hard on newcomers. You are the experts, and you deserve to be treated with respect. That means, visitors that come there should assume they know less than you. If someone wants to argue about correctness of the science, this should not be the place – he should rather publish it in a journal. If someone wants to learn, he can ask questions, with respect, provided he does his homework and doesn’t ask questions which are already contained in “start here” section.
On the other hand, if you moderate comment out, there should be a box saying why it was moderated, pointing out to this policy and “start here” (or some sort of FAQ). I would also add to the policy, if someone has a feeling his question wasn’t answered, he should cite in the comment a part of FAQ he doesn’t understand, to at least prove that he read it. The FAQ should be updated with new questions.
This way, it won’t become tiresome (hopefully) to answer newbies’ questions. Of course, there would be people bitching about those rules, but that can’t be helped. Science is not a democracy (and I say it as a big fan of direct democracy).
Leo G, it’s not carbon that’s a greenhouse gas, it’s carbon dioxide (and many others). So wherever you got your original explanation, it wasn’t really right.
Most of the first hits from this are decent explanations:
Yes, the bonds that hold the molecule together are involved.
These bonds and how they interact with photons are not neither “absorbtion” nor “adsorbtion” as those are usually used in chemistry.
There are a lot of “explanations” at different school levels for what these bonds are; with only high school chemistry some years ago, you probably got the same sort of explanation I did, and it’s closer to poetry than a real explanation. If you got to how electrons are shared in molecules, “orbitals” and energy levels that’s a bit better idea. But without the math it’s _still_ poetry, mostly.
Philippe Chantreau (#1043), CLOUD would be further along had politics not delayed funding for most of a decade. That link you found is regarding the results from the initial apparatus, which, by my understanding, was a prototype (CLOUD-6 in 2006) to verify the results of the Danish SKY experiment (the published results cleared the CERN funding roadblock) and to better understand the issues needed for the second generation CLOUD-9 apparatus meant for insertion into a CERN particle beam. CLOUD-9 is (iirc) now being used to gather data. That, taking into account what was learned from -6, was in the making for about three years.
An interesting reviewed article that I hope most of you read, rather than accept the RC summary of why you shouldn’t bother, is of course Svensmark et al. “Cosmic ray decreases affect atmospheric aerosols and clouds” Geophysical Research Letters, 2009. The seven day delay between a strong Forbush event and the detected decrease in cloud cover is another SKY/CLOUD mechanism.
Anyone wanting the Reader’s Digest version, there’s always ScienceDaily. I salute them, they are better known for uncritically passing on alarmist press releases:
Steve Fish # 1042 said: Regarding the agonizing here about whether to stick to the science and exclude pseudo skeptic remarks, or be more open– The problem is that being more selective can also throw out those who genuinely want to learn, and just beginning with the science, with the bath water.
Right, that’s why having another forum that such discussions can be redirected to might be a good compromise. Then “censorship” would be less of an issue. Everyone still has his/her say (unless it gets ridiculous of course) and can get answers.
If at another site as Hank suggests it might be good to state that the other site is associated with RC so that it’s not like people are being completely ejected from the main site. I think that reasonable people among the newbies would understand.
More controversially, if this occurred, it might be productive and interesting to then formally invite the more (albeit comparatively few) scientific of the skeptic crowd to the science site where pro/con can now talk directly to each other rather than past each other on differing sites. And more of us would enjoy lurking on the main science forum to learn from the experts.
Reisman (#1054) there is a nice treatment of a Laschamp event in Kirkby’s “Cosmic Rays and Climate”. See section 2.3.2 Laschamp event.
Also, since I’ve not made a claim that CO2 (or methane or…) is not a greenhouse gas, and would not make that claim, it is curious you expect me to prove that is so. Are you confusing my posts with someone else’s?
Greg C (1057) since I was referring to the increase in the fraction of the atmosphere that is CO2, 0.01% is indeed correct. Were I to refer to the current total fraction to one significant digit, your 0.04% would be accurate.
And for Jim Eager (1058) I made no claim that 0.01% was insignificant, just that I find that the sun being more energetic over the period (about 100% more, by Solanki, to an 8000 year maximum) should at least get the same notice, especially if one accepts it was cold during the Maunder and Dalton minimums.
[Response: You think that the sun has doubled it's output over the last 8000 years? Really? Think about it a little. - gavin]
Revising my suggestion a bit. What if it were as simple as two different comment buttons side by side on the very same RC articles – one for the experts and protected by IP and/or email address filters or whatever arrangement is used and the other for everyone else? Everyone gets to comment on the same article. Those who want to go off on a (related) tangent are allowed and those of us who want to read the higher on topic debate are not denied that option.
If I’m off in left field feel free to tell me so.
Right, that’s why having another forum that such discussions can be redirected to might be a good compromise. Then “censorship” would be less of an issue. Everyone still has his/her say (unless it gets ridiculous of course) and can get answers.
I thought RC was about communicating climate science to the public. The “About” page states it pretty clearly. I wouldn’t want RC to turn into a place only for scientists talking to each other. That’s what conferences and peer reviewed journals are for. I come to RC to read about climate science issues from actual climate scientists, not wanna-be auditors or self-styled skeptics. The “About” page also states that the forum is moderated and as such, anyone who posts must recognize that any OT posts and the like will be moderated. Seems clear and fair and necessary.
Maybe it’s time for yet another RC article on GCR’s, solar forcing, and climate, again…
Greg Goodknight, seriously, read the RC material on solar forcing (scroll down to find a bunch of links of solar forcing):
I’d like to know your thoughts after a thorough review. As I recall there is this thing about CCN’s and affect of GCR’s and time spans??? hmmm… think I will review a bit too :)
Re Gavin’s response to 1070. Greg G. was probably referring to the suggested or deduced solar forcing over the past 8000 y compared to the anthro CO2 forcing to date. But, I suspect Greg can clarify that himself.
I second the idea of a (guest?) post on the current capabilities of regional climate projections. My rather elimentary understanding is that these are still considered to be somewhat unreliable when it comes to the most important quantity, precipitation.
Some time ago I read a regional forecast fo Argentina which included some about Chile as well. I studied the projection for the rest of this century with care just for Patagonia, since weather patterns are actually quite predicatable there. The general conclusion was increased drought, in keeping with the trend seen in the records of the 20th century. Based on some readinag about paleoclimate in Patagonia, I agree.
The only surprise was a prediction of increased precipitation along the southeast coast and a bit inland. That does not seem in keeping with the one paleoclimate study from that area which I have read. (Indeed, it might be the only one.) To what extent can I trust such a prediction of increased precipitation in a rather small area?
#1069 Greg Goodknight
I’m not confusing you with anyone else. If GCR’s are the culprit and CO2 and other GHG’s are quantifiable in amount and forcing, and since positive radiative forcing is now around 3.6 W/m2 (apparently caused by GCR’s according to you) then if you add the GHG’s and and their forcing, we should be somewhere around 7.2 W/m2 above thermal equilibrium. Right?
So I am waiting for you to prove your claims. Prove that radiative forcing is now around 7.2 W/m2 above thermal equilibrium.
@ Greg Goodknight # 1070 – “since I was referring to the increase in the fraction of the atmosphere that is CO2, 0.01% is indeed correct.”
Oops, okay, I see now that I misunderstood what you had meant. Nonetheless, I stand by my original point that your use of the number “0.01%” seems to be to suggest that common sense should indicate that such a small amount of additional CO2 could not possibly have the magnitude of the effect predicted by AGW, when in practice the real world tends to violate our intuitions about how it should work all the time, and so the fact that “0.01%” *feels* like a small number is completely irrelevant.
- “find that the sun being more energetic over the period (about 100% more, by Solanki, to an 8000 year maximum)”
Solanki said no such thing about the luminosity, so presumably you are referring to something like the number of sunspots? Also, it’s not like the models of the climate haven’t been accounting for solar variability; rather, even accounting for this, it was determined that solar variability alone was insufficient to account for the observed change. Scientists do tend to be curiously natured people by-and-large (otherwise, they’d get a better job!) so it’s not like they wouldn’t have investigated this possibility if it seemed like a plausible explanation.
Gavin, that’s not quite what I wrote and certainly not what I meant. From Solanki’s letter to nature, using sunspot numbers as a proxy for magnetic energy, the sun reached a maximum not seen for about 8000 years, but that about doubled from the level in the very early 20th century.
Obviously, it’s settled science that incident sunlight varies very slightly with the solar cycle.
Yes, Solanki et al. have made it clear they believe it “unlikely to have been the dominant cause” of the 20th century warming, leaving open the issue of how much of a warming that might be attributed to it, but others have made their disagreements clear and now it does seem the detected cloud response to some Forbush events has established a physical mechanism.
I realize RC has made it clear the opinion here is that the lack of gcr trend since the mid 50′s means that gcr as a significant cause of warming, but since that doubling was already underway by then it would seem to me the lack of a later trend does not falsify the gcr theories.
I managed to drop part of a sentence, if I may revise my last paragraph (IN CAPS):
I realize RC has made it clear the opinion here is that the lack of gcr trend since the mid 50′s means that gcr as a significant cause of warming SHOULD BE CONSIDERED FALSIFIED, but since that doubling was already underway by then it would seem to me the lack of a later trend does not falsify the gcr theories.
Greg G @1070 wrote, presumably with a straight face:
“And for Jim Eager (1058) I made no claim that 0.01% was insignificant”
Sure you didn’t, Greg, but then you didn’t really need to be that explicit when choosing a metric that allows you to quantify the increase in CO2 as one hundredth of one percent.
That slight of hand may work on a non-science public blog, but it won’t cut it here, where it makes you look either foolish or devious.
you said: “The seven day delay between a strong Forbush event and the detected decrease in cloud cover is another SKY/CLOUD mechanism.” -?? The delay is a mechanism? Please parse — I’m curious what you actually meant.
Comment by Ron R. — 28 December 2009 @ 3:47 PM:
Hi Ron. I have no objection to a companion RC site, but I would not dare ask Gavin and company to increase their workload in order to accomplish this.
Greg Goodknight, did you mean that a pre-1950s trend in GCRs is still causing increased temperature because of a lag in its effect?
But the Earth’s energy imbalance has not been decreasing. Same reason the effect of solar radiance’s increase up to then cannot lag this long. Ditto CFCs.
New poster here, please be gentle. I’ve been mugging up on my late 1980s geography undergraduates’ knowledge of climate change / AGW of late, starting with the UK Met Office website and then arriving at this excellent website here.
As a non-expert, non-physicist AGW adherent, could somebody point me to a layman’s explanation of how time lags in the climate system are figured out. No doubt this is a very dumb question (but it’s sincerely dumb), but I’d like to get a basic understanding of how it is that some forcings play out over a few short years eg. El Nino, volcanic eruptions, but others pan out over decades – specifically, we are frequently told that the full temperature impact of anthropogenic emissions already released into the atmosphere will take several more decades to fully take effect. Maybe I’m not looking in the right place, but I haven’t found a concise summary yet. Thanks in advance.
Uh, Gary Goodknight, you can’t really mean that solar flux has doubled–that would raise global temperatures by about 19% on the Kelvin scale, and since we are still all alive, I presume this has not happened. Care to clarify what you mean by “doubling”
Owen B (1084) — Roughly, the atmosphere (box one) responds faster than the oceans (box two). For more, I suggest
and also the links therein to the two box model.
Owen B. (#1084),
As another non-expert I think it’s a pretty good question. Perhaps RC would be willing to do an introductory post about different time lags in the climate system? Meanwhile, here’s one partially helpful pointer:
CM (1081) — The findings of the SKY experiment and the CLOUD-6 experiment was that very small particles were formed fairly quickly. The handwaving was that these would grow with time to be a size known to be effective cloud condensation nuclei.
The seven or eight day delay for the cloud decrease to be noted after strong Forbush events likely to have an effect was apparently the first good experimental evidence that this was indeed happening in the real atmosphere, and how long it would take.
Had Svensmark’s SKY been well funded he might have been able to go further, but it’s my understanding he started the effort without any funding in place, and only got as far as he did after a $600K grant from the Carlsburg Foundation, the largest private grantor of funds for basic science in Denmark. Carlsberg, the best beer in the world, due to chemistry.
Jim Eager (1080) — Now that we’ve established that 0.01% of the atmosphere can have a significant effect, can we agree that a 100% increase in solar magnetic energy might also have a significant effect?
Tom Dayton (1083) — My understanding of the theories is that a decrease in GCR starting in the ’40′s due to heliosphere changes can be expected to have decreased low cloud levels and kept them lower for the duration. A small decrease in albedo, more or less during the entire space age. I recall reading about the old Earthshine project at the Big Bear Observatory, and that the variation of albedo was large compared to the IPCC determination of warming ascribed to CO2.
Here’s something Earthshiny…
“Traditionally the Earth’s albedo has been considered
as a roughly invariant parameter in global circulation
models and climate studies. With the earthshine project,
we have shown how, on the contrary, the Earth’s albedo
is quite a variable parameter for which a detailed study
of its seasonality, long-term variability and climate
implications need to be carefully undertaken, if we are
to fully understand the present changes in the Earth’s
As far as I can tell, at the moment no one really has a clue as to exactly what particles and energies have what effect, so probing questions will have to be answered “hell if I know”.
[Response: Read this. - gavin]
Interesting. Never knew about the .5% of the atmosphere being the absorbing gasses. Hmmmm.
Last question for a while, (as you all have given me a lot of homework!)
My understanding right now is that CO2 concentrates (lumpily I now gather from NASA :) )
in the upper troposphere. When re-emitting the photon (again very simplistic), The usual quote is that there is a 50% chance of it heading back earthwards. But can the height of the actual molecule not change this to maybe only 40-45% chance of re-emmitance towards earth?
(i.e. – higher up, some re-emmitance from below horizontal would not “see” the earth)
Uh, Rey Ladbury (1085), note that I never claimed a change for solar luminance, since clarified, but I believe both magnetic and solar wind fluxes did indeed double but have since crashed.
Do you ever tire of the “Gotcha!” game?
Owen B (1084) & CM (1087) — Climatologist W.F. Ruddiman’s textbook for non-science students, “Earth’s Climate: Past and Future” is organized around the different timescales. I started (after having read his “Plows, Plagues and Petroleum”) and certainly recommend it. Of course, there are several other starting good books such as David Archer’s, which has the advantage of videos of lectures freely available; see a prior thread here for the link.
Steve Fish #1082: Hi Ron. I have no objection to a companion RC site, but I would not dare ask Gavin and company to increase their workload in order to accomplish this.
Your right, that’s why I suggested that the new forum be moderated by other intelligent regulars here (I’m not suggesting myself obviously as I’ve still a lot to learn). That would leave Gavin and co to stick to the science.
I was just throwing out an idea as people are getting worked up, and rightly so IMO, about all the noise drowning out the signal.
Thanks for the RealClimate link, Gavin, I have seen it before. Particularly unsatisfying is the mention, without citation, that “A recent study found that a change in GCR intensity, as is typically observed over an 11 year solar cycle, could, at maximum, cause a change of 0.1% in the number of CCN.”
If that’s the study that I’m thinking of, it’s a computer simulation, not an actual measurement. As the chair of my alma mater’s chemistry department liked to say, “one clean experiment is worth a thousand dirty equations”. I’m not sure, for example, forcing GISS GCM II-prime into service standing in for the real world should trump either the real atmosphere or a CERN experiment using real particles.
[Response: Not quite clear why you have to throw in a sneer about models - perhaps you'd like to explain how you are going to observe all the clouds and aerosols in the world and derive exactly how much of the cloud-aerosol interaction is due to aerosols that were nucleated by GCR ionizing radiation and managed to survive growth to CCN and happened to be in an environment conducive to cloud formation? I'm sure everyone will be very impressed. Similarly, I'm fascinated to know how CERN is actually going to work out how their aerosols will interact with clouds when they won't have any clouds in their experiment. Surely they aren't going to use some kind of model to explore the global sensitivity of whatever it is they find at the aerosol formation stage? Golly. - gavin]
Greg Goodknight — 28 December 2009 @ 3:43 AM
Shaviv and Veizer (2003). A major problem with that paper is that Veizer himself reinterpreted his paleotemperature data, and the extremely tentative “correlations” between the putative CRF variation and temperature in S/V2003, doesn’t “correlate” any more [*]. Veizer considers that the paleoproxy temperature data is coupled to the atmospheric CO2 concentration (at least during the Paleozoic part of the Phanerozoic). This is consistent with what is now an extremely large body of evidence that paleoproxy temperature data is strongly linked with paleoproxy CO2 measures throughout the last 500-ish million years.
[*] R.E. Came, J.M. Eiler, J. Veizer et al (2007) “Coupling of surface temperatures and atmospheric CO2 concentrations during the Palaeozoic era” Nature 449, 198-202
The Jasper Kirby video is disappointing; For example, he makes some unfortunate errors in insinuating that well-established contributions (CO2, solar irradiance changes) can’t have made a significant contribution to the temperature increase from the LIA to the mid 20th century. The Moberg temperature reconstruction he shows gives a LIA to mid-20th century temperature rise of around 0.6 oC. Kirby asserts that CO2 variation can’t have made a contribution to climate change pre-20th century. However we know that the pre-industrial CO2 levels (280 ppm) rose to 300 ppm by 1900 and 310 ppm by 1940. That gives an equilibrium temperature contribution of 0.3 oC (280-300 ppm) or 0.45 oC (280-310 ppm), using the middle of the range of likely climate sensitivities (3 oC of warming per doubling of atmospheric CO2). Since this rise covered a long period, we can expect a substantial temperature contribution (say 0.35 oC by mid 20th century).
Likewise Kirby shows Judith Leans irradiance reconstructions (mislabelled, since Lean 2002 only covers solar data back to 1840). Kirby’s graph actually looks like Leans 2005 reconstruction [**]. Lean calculates a change in solar irradiance forcing of 1 or 1.4 W/m2, which corresponds to a temperature rise of 0.14 – 0.2 oC (not the “few hundredths of a degree” that Kirby asserts). Likewise Kirby ignores the evidence that enhanced volcanic activity likely made a conrtribution to temperature suppression at the LIA [***].
[**] Y.-M. Wang, J. L. Lean and N. R. Sheeley, Jr. (2005) Modeling the Sun’s Magnetic Field and Irradiance since 1713 Astrophysical J. 625 522-538
[***] see e.g. Figure 7 of: [*] P.D. Jones and M.E. Mann (2004) Climate over Past Millenia Reviews of Geophysics, 42, RG2002.
So even using a fairly conservative combination of rather well-characterized forcings (e.g. 0.35 oC from CO2, 0.15 oC from solar irradiance, 0.1 oC from recovery from volcanic cooling), the entire temperature rise from the LIA can be understood. Of course that doesn’t mean that that’s exactly how the LIA – mid-20th century temperature rise was forced. However there’s no good scientific reason for either pretending these contributions don’t exist, or interpreting them incorrectly.
One might also point out that an inspection of Kirby’s figure showing the Moberg temp reconstruction/14C reconstruction for the period of the MWP shows that during that entire period the temperature change lead the 14C change right throughout this period. At face value this negates any significant contribution from the CRF to MWP temperature variation.
And the more general problem of course is that the 14C variation is a function of variation in solar activity. One can’t ascribe this specifically to the CRF component of the solar variability, without ruling out a dominant contribution from the solar irradiance contribution (as in the case of the LIA)….
Rich Creager #1059, :-D
Yet another way to waste time on the internet. I’m looking for a way to actually lessen my time in front of the computer.
New Year’s resolution.
It’s only tiring because we don’t get paid by the post, by you do. Or do you get paid by the hour?
Greg Goodknight, galactic cosmic ray fluxes have not changed appreciably (modula the solar-cycle variation) since the 1950s. I can say with pretty reasonable certainty that in my day job, I would have noticed such changes had they occurred as they would have affected single-event upset rates on satellites. Do you seriously believe that there’s a 30-50 year lag in GCR effects? Do you realize what that would mean for CO2 sensitivity?
I’m an agnostic on GCR. However, I don’t see how GCR give you:
1)stratospheric cooling along with tropospheric warming
2)greater warming in winter than summer
4)how GCR could fake 10 separate lines of evidence all pointing toward a CO2 sensitivity of 3 degrees per doubling.
And on and on. See the problem is that you have to look at all the evience, and then GCR don’t look so good. Of course, then there’s the fact that the mechanism is still pretty half-baked. Are you sure you want to reach for this straw?
Leo G., The vast majority of excited CO2 molecules relax by imparting their excess energy to N2 (or O2 or Ar or other CO2) molecules during collisions.
Also, I wouldn’t overstate the lumpiness–that’s a pretty short-term effect. Over time, the CO2 spreads out from its sources.
Leo, just check the wiki page on Earth’s atmosphere:
78+% nitrogen (N2), 21-% oxygen (O2), 1-% argon, none of them IR absorbers Earth’s atmosphere, but that’s for a dry atmosphere because water vapour is not evenly distributed.
Water vapour can be as high as 4% locally at the surface in the tropics but falls off as latitude increases and temperature falls and falls off rapidly as elevation increases and temperature falls rapidly.
You are correct that altitude increases what can be considered “up”.
Greg Goodknight, it doesn’t matter what the purported mechanism of GCRs’ change is. My point was that once the GCR changes stopped, the resulting energy imbalance of the Earth must “immediately” have started to decrease as the Earth “immediately” started to heat and therefore radiate more to match the new, now constant, level of GCRs.
Substitute for the word “GCRs” in that last sentence, “cloud cover,” or any mechanism you desire. The mechanism doesn’t matter. That’s why I linked you to the Skeptical Science posts on how we know that Earth’s heating since the 1950s cannot be due to the Sun’s higher output that plateaued in the 1950s. The same argument applies to any factor once it stops changing.
(Side note to Owen B.: Those links all are relevant to your question about lag.)
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