I received this presentation of the “Bjerknes Lecture” that Dr. James Hansen gave at the annual meeting of the American Geophysical Union on December 17th. There are the usual things one might expect in the presentation, such as this slide which shows 2008 on the left with the anomalously warm Siberia and the Antarctic peninsula:
Source: James Hansen, GISS
Off topic but relevant, NASA has recently “disappeared”updated this oft cited map showing warming on the Antarctic peninsula and cooling of the interior:
There is also some new information in Hansen’s presentation, including a claim about CO2 sensitivity and coal causing a “runaway greenhouse effect”.
Hansen makes a bold statement that he has empirically derived CO2 sensitivity of our global climate system. I had to chuckle though, about the claim “Paleo yields precise result”. Apparently Jim hasn’t quite got the message yet that Michael Mann’s paleo results are, well, dubious, or that trees are better indicators of precipitation than temperature.
In fact in the later slide text he claims he’s “nailed” it:
He adds some caveats for the 2xCO2 claim:
Notes:
(1)
It is unwise to attempt to treat glacial-interglacial aerosol changes as a specified boundary condition (as per Hansen et al. 1984), because aerosols are inhomogeneously distributed, and their forcing depends strongly on aerosol altitude and aerosol absorbtivity, all poorly known. But why even attempt that? Human-made aerosol changes are a forcing, but aerosol changes in response to climate change are a fast feedback.
(2)
The accuracy of our knowledge of climate sensitivity is set by our best source of information, not by bad sources. Estimates of climate sensitivity based on the last 100 years of climate change are practically worthless, because we do not know the net climate forcing. Also, transient change is much less sensitive than the equilibrium response and the transient response is affected by uncertainty in ocean mixing.
(3)
Although, in general, climate sensitivity is a function of the climate state, the fast feedback sensitivity is just as great going toward warmer climate as it is going toward colder climate. Slow feedbacks (ice sheet changes, greenhouse gas changes) are more sensitive to the climate state.
Hansen is also talking about the “runaway” greenhouse effect, citing that old standby Venus in part of his presentation. He claims that coal and tar sands will be our undoing:
Hansen writes:
In my opinion, if we burn all the coal, there is a good chance that we will initiate the runaway greenhouse effect. If we also burn the tar sands and tar shale (a.k.a. oil shale), I think it is a dead certainty.
That would be the ultimate Faustian bargain. Mephistopheles would carry off shrieking not only the robber barons, but, unfortunately and permanently, all life on the planet.
I have to wonder though, if he really believes what he is saying. Perhaps he’s never seen this graph for CO2 from Bill Illis and the response it gives to IR radiation (and thus temperature) as it increases:
It’s commonly known that CO2’s radiative return response is logarithmic with increasing concentration, so I don’t understand how Hansen thinks that it will be the cause of a runaway effect. The physics dictate that the temperature response curve of the atmosphere will be getting flatter as CO2 increases. Earth has also had much higher concentrations of CO2 in past history, and we didn’t go into runaway then:
Late Carboniferous to Early Permian time (315 mya — 270 mya) is the only time period in the last 600 million years when both atmospheric CO2 and temperatures were as low as they are today (Quaternary Period ).
There’s lots more in this paper to behold in wonderment, and I haven’t the time today to comment on all of it, so I’ll just leave it up to the readers of this forum to bring out the relevant issues for discussion.
I’m sure Steve McIntyre at Climate Audit will have some comments on it, even though his name is not mentioned in the presentation. My name was mentioned several times though. 😉
re George E. Smith 13:00:45 on the fact that CO2 changes lag behind temperature change in the ice-ages record.
Sorry if I failed to explain this to you–isn’t it obvious? The lag is not good news. Rather, it strongly confirms that the Milankovitch-cycle shifts in sunlight over tens of thousands of years regularly initiated a powerful feedback loop. I think essentially everyone agrees that the close of a glacial era comes when solar insolation in mid northern latitudes results in less snow cover in late spring and perhaps early fall, bringing a slight rise of temperature. The long-standing puzzle as to how this slight change could drive a glacial cycle is answered once we understand that the small temperature rise stimulates a substantial increase in gas levels (not only CO2 but also methane, which follows a similar path); this drives the temperature higher, which drives a further rise in the gas levels, and so forth. The process takes quite a few centuries. Ice ages are thus the reverse of our current situation, where humanity is initiating the change, setting the feedback in motion, by adding greenhouse gases — although far faster, and reaching a far higher level, than anything in the Pleistocene record.
Jack Simmons
December 22, 2008 6:25 am
foinavon (16:11:33) :
Dave Dodd,
I suspect you’ll find with deeper investigation that Beck’s data is not a reliable atmospheric CO2 record, although it is interesting in the historical sense…
These values are woefully inadequate as measures of atmospheric CO2, since cities give very high CO2 levels as they’re close to emission sources.
Aren’t the current measures of CO2 from Hawaii close to emission sources, that is, volcanoes?
Will (22:38:48)
I don’t think it’s an “ad hoc assertion”! There’s a lot of data on aerosols and their cooling and warming contributions, and even though the errors associated with quantifying their effects are large, they certainly have to be included in consideration of the historical temperature evolution and future effects.
There’s still a very strong aerosol load apparently, and this is protecting us somewhat against the warming effect of enhanced greenhouse gases. I described some of the data summarised by Carmichael and Ramanathan in their recent review in a post above. HereHere’s the source again:
V. Ramanathan & G. Carmichael (2008) Global and regional climate changes due to black carbon; Nature geoscience 1, 221-227.
Essentially the same data can be accessed from Ramanathan’s testimony before the Wegman oversight committee hearing last year: http://oversight.house.gov/documents/20071018110734.pdf
Attribution of the contributions from aerosols can be found there. Likewise ice core data can be used to for determining black carbon and sulphurous aerosols in great detail, although the levels in ice cores likely give a localized measure:
J. R. McConnell et al (2007) 20th-Century Industrial Black Carbon Emissions Altered Arctic Climate Forcing. Science 317, 1381 – 1384.
more global scale analysis of emissions and their contributions have come from detailed fuel use statistics and suchlike:
e.g. Novakov T (2003) Large historical changes of fossil-fuel black carbon aerosols, Geophys. Res. lett. 30,, art # 1324
but I suspect these aren’t as precise as we would like, and it’s not an easy subject to quantitate. It does seem to be reasonably well established that the aerosol load is actually substantially greater now than through the 50’s-60’s, but then the greenhouse forcing from excess CO2 during this period wasn’t actually than large either (< 0.3 oC at equilibrium).
Wondering Aloud
December 22, 2008 6:51 am
Wow Hansen has “nailed it”! I don’t notice any data though, or even an explanation of a logical line of reasoning that doesn’t assume all the effects he is supposed to be measuring?
Hypothesis is not theory, theory is not fact. The burden of proof is supposed to sit squarely on the theory in question.
Computer model runs are not data, corrections to the temperature record also known as WAGs are also not data. I like foinavon waving away all the paleo data. In the past CO2 has clearly not been a major climate driver, nor is it even evident that it is a positive effect despite a prediction based on incorrect assumptions from Arrhenius.
If you think Hansen has any credibility it isn’t because of science. Until he releases his raw data and his methods for doing his calculations the logical conclusion is fraud.
foinavon
December 22, 2008 7:09 am
Bill (03:55:54)
re: Question I have is that if the temperature response to CS (Climate Sensitivity) is logarithmic as Dr Hansen and most seem to agree then why:
1) is the temperature increase primarily linear? Only way that happens I think is if CO2 growth is exponential, yes?
Good question. The temperature response in an ideal world with an instantaneous forcing (e.g. add 386 ppm’s worth of CO2 into the atmosphere as now and then stop and wait to see what happens!) would be something like a hyperbolic rise to a new equilibrium:
e.g. T = Tmax*t/(t+k)
where T is the temperature, Tmax is the temperature at equilibrium that will eventually result from the effect of the forcing, t is time and k is some constant that relates to the intertia in the system.
This should give a hyperbolic change in temperature that tends towards Tmax.
Even within this simple model the temperature change might appear linear since the early parts of a hyperbolic are near linear (t <k). Likewise as you say, the forcing is an ever increasing one since we are continuing to pump CO2 into the atmosphere. This will also tend to make the temperature trend more linear… 2) Given the 2.5 – 3.5C temperature in response to doubling CO2 from 280ppmv and we are currently nearing 400 ppmv (about halfway there) should we not have already seen about 70% of the 2.5-3.5C temp increase?
We can calculate the temperature rise expected within a 3 oc climate sensitivity (CS) (280-400 ppm change) as 1.5 oC, so yes, your value of around 70% is about right. However this is the change expected at equilibrium. It comes back to the inertia in the climate system defined by in the equation just above (in fact there are many different ‘s with different elements of the climate system equilibrating on different timescales). So we don’t expect to get the full “whack” of our current emissions until some decades into the future…
It also seems that the earth’s temperature response to enhanced greenhouse gas concentrations is somewhat suppressed by our aerosol emissions:
see, for example the testimony from V. Ramanathan before the Wegman oversight committee last year which is very informative on the current aerosol science: http://oversight.house.gov/documents/20071018110734.pdf
foinavon (05:59:16)…
You wrote:
“The Scotese graph with a pseudo-”paleotemperature/paleoCO2 evolution” is also horribly incorrect, but that’s another matter!”
I’m sorry, but the Scotese graph has been corroborated using other proxies (i.e isotopes and iron stained grains) and it is correct. If you read the references at the bottom of the diagram, you would find other authors who have found the same results.
Hansen makes a bold statement that he has empirically derived CO2 sensitivity of our global climate system. I had to chuckle though, about the claim “Paleo yields precise result”. Apparently Jim hasn’t quite got the message yet that Michael Mann’s paleo results are, well, dubious, or that trees are better indicators of precipitation than temperature.
Since his argument isn’t based on Michael Mann’s paleo results, I don’t see that this message (assuming it to be true…another whole can of worms) is particularly relevant.
Bill Illis says:
First, where is the solar reduction part of the equation due to the Milankovitch cycle. This formula says it doesn’t even play a part including kicking off the ice albedo in the first place.
Yes, changes in solar insolation kick off the ice albedo changes. However, these changes are in the distribution of solar insolation. The total amount of solar insolation hitting the earth does not change (or not appreciably).
Second, his math is wrong if the sensitivity is 3.0C per doubling because a reduction to 180 ppm from 280 ppm only results in a decline of 1.9C (picky I know but he is the one who says he has nailed it empirically – the formula doesn’t even work).
Your calculation includes only CO2. His presumably also includes methane(and maybe NO2?).
Noblesse Oblige says:
I have seen at least a half dozen empirical estimations of the climate sensitivity done by a variety of different methods, and their range runs from less than 1 to ~ 1.7 deg C for doubling. They use a variey of correlation techniques (e.g., Douglass and Christy) or estimates of the temperature relaxation time (Schwartz, Scafetta).
Actually, Schwartz has revised his estimate in the reply to the comments on his original paper. His new estimate is something like 1.9 C and has large enough error bars to overlap with a good portion of the IPCC range. (And my guess is some of the commenters on his paper would argue his new estimate is still too low based on the problems they identified in his paper.)
Phil, have you had a bad eperience with “foinavon” in the past? Is that something I might know about?
Yes, my money was on Red Alligator! http://en.wikipedia.org/wiki/Foinavon
My issue with Bill’s data fits is that he treats the baseline [CO2] as one of his parameters, in the latest graph it’s as high as 334ppm
Joel Shore
December 22, 2008 7:36 am
Richard deSousa says:
Hansen also fails to mention Venus’s atmosphere is 97% CO2… how he can jump from Earth’s atmosphere of .03% CO2 to runaway global warming is beyond comprehension… he’s completely an imbecile…
That is it’s composition now but the question would be what its composition was before the runaway greenhouse effect got going. In particular, all the water on Venus boiled into the atmosphere when it got very hot, dissociated and then I think it eventually escaped into space. It is also worth noting that although nitrogen only makes up ~3.5% of the current Venus atmosphere, this is not a small amount of nitrogen considering that the air pressure on Venus is currently 92X that on earth.
Since Hansen is one of those responsible for understanding the greenhouse effect on Venus, I think he might know a little more about it than you do. (That said, I must admit that I am also surprised to hear him argue that a runaway effect could occur here on Earth, since most scientists that I know of, such as those at RealClimate, argue that a true runaway on Earth is not in the cards. I would like to hear the arguments on both sides.)
tty
December 22, 2008 7:39 am
“Philip_B (05:50:54) :
Human-made aerosol changes are a forcing, but aerosol changes in response to climate change are a fast feedback.
Oh Boy! A new magic fudge factor.”
You don’t know how right you are. There is strong evidence that aerosols (dust) is a very important factor in the sharp swings between glacial and interglacial climate. What Hansen is trying to do is to claim that GHG is the one important thing and everything else (including aerosols) is feedback. That bit about “fast” feedback, is because dust levels change very quickly in ice-core records when the climate shifts, much faster than the CO2 levels, so for “fast” read “effect before cause”
tty
December 22, 2008 8:03 am
foinavon, would you perhaps indicate where in your opinion correct paleotemperature/CO2 level curves are to be found?
By the way only the paleotemp curve is due to Scotese, as you would have seen if you had bothered to check. Incidentally the original has rather more detail during the Cenozoic, Anthony selected a simplified version.
JimB
December 22, 2008 8:05 am
OT, but thought it was interesting anyway…
Anyone in New England with access to the cable channel NECN, as part of their 30 minute “news loop”, they are reporting that even though THIS Christmas will be white, Global Warming is threatening to eliminate ALL white Christmases in the future…
They can even tie it into the holidays.
Wonder what Dickens’ Tiny Tim would have thought about that…
JimB
Joel Shore
December 22, 2008 8:05 am
E.M.Smith says:
Do you have a citation?
….
I’d say a more accurate description would be that “a research associate provided the computer programs that lead to the claim of global cooling.”
All is see is Hansen backpedaling from his earlier model to a newer model.
Hansen explains here that what he gave Rasool was a code to do Mie Scattering calculations. Mie Scattering is something that was worked out around 1900, although the formulas are complicated enough that it would have been a non-trivial task to write code to calculate them back in 1971. (Today, with routines to compute Bessel functions and Legendre Polynomials more readily available, it is much easy to calculate Mie scattering and many people, including myself, have written our own codes.)
To say that Hansen or his model predicted cooling because that is the result that Rasool got is not much different than saying that Newton predicted cooling because Rasool used calculus, invented by Newton, to get his result. (In fact, Newton actually invented, or co-invented, calculus whereas Hansen merely codified the theory already worked out by Mie, so Newton’s connection is more direct.)
It is also worth noting that although the initial paper by Rasool and Schneider in 1971 did predict that cooling due to aerosols would win out over warming due to GHGs, the authors themselves admitted it was a first calculation…and, particularly in response to a comment on their paper, were very clear in noting that their calculation had a variety of potential inaccuracies. Within a few years, Schneider had done further calculations that made him realize that warming would likely win out over cooling. (It is also worth noting that in 1971 it was by no means clear that the U.S. and other Western countries would begin to sharply curtail their emissions of aerosols because of the Clean Air Act and other legislation…and thus that these emissions would not continue to grow exponentially.)
As for the other predictions, our understanding of the greenhouse effect and the consequences of its amplification include enhanced tropospheric water vapour,…./foinavon
Which is also not happening so far, consistent with the fact that water vapor alone has not produced the maximal theoretical “greenhouse” effect it otherwise should have, according in part to the very same energy wave absorption mechanism alleged to operate in the case of CO2 [coupled with water vapor’s increasing concentration per atmospheric temperature increase] – an effectively real damping regulation probably due to the operation of climatic mechanisms involving heat energy blocking and dissipation by means of cloud formation, release of latent heat during water vapor precipitation, and convection.
And why these same mechanisms for regulating water vapor’s “ghg” effect would not also work in the case of CO2’s so as to further blunt the alleged large temperature effect from doubling [a small] atmospheric CO2 concentration, is certainly a mystery to me, again especially noting that water vapor concentration is not increasing, but even instead decreasing with increased CO2 concentration.
Moreover, regarding any alleged correlation between CO2 concentrations and temperature over some range of CO2 concentration, if CO2 concentrations follow/lag temperature increases quickly enough, a relevant correlation between them of some significance could be present but not a CO2–> temperature causation. Apparently, previous concentrations of CO2 much higher than those of today have not abetted warming temperatures nor prevented atmospheric temperature decreases.
Joel Shore
December 22, 2008 8:46 am
Pk att says:
Question. If Venus has run away global warming, why is its temp not continuing to rise over time? Is that not the definition of “run away” temps?
No…Eventually, there are forces that come in that stabilize the temperatures. A definition of “runaway” that required such stabilization to never occur and the temperatures to run off to infinity could certainly be proposed but would not be very interesting since such a scenario would never occur. (In particular, I believe you’d be violating the laws of thermodynamics if the temperature of the atmosphere got larger than that of the surface of the sun.) I am not sure if a precise definition has been settled upon but I doubt that any scientist would argue that temperatures rising to the point where all the water in the oceans boils away should not constitute “run away global warming”!
Bill Marsh says:
1) is the temperature increase primarily linear? Only way that happens I think is if CO2 growth is exponential, yes?
One thing that many people fail to realize is that all functions are locally linear over a small enough range unless you are right at a point of zero slope. So, over a small enough range, it is difficult to distinguish between logarithmic and linear or between linear and exponential. And, that range is not all that small: For example, if we assume a linear relationship for temperature for CO2 concentrations between 280 and 560 ppm, we get that our current concentration of ~385 ppm is 37.5% of the way there whereas if we assume the expected logarithmic relationship, we get that it is 46% of the way there, not that huge a difference.
2) Given the 2.5 – 3.5C temperature in response to doubling CO2 from 280ppmv and we are currently nearing 400 ppmv (about halfway there) should we not have already seen about 70% of the 2.5-3.5C temp increase?
I am not sure how you came up with the 70% number. My number of 46% is more accurate. Furthermore, you have to understand that the estimate you quote for a temp increase is the EQUILIBRIUM climate sensitivity…and we are pretty far outside of equilibrium…i.e., we haven’t yet seen the full response of the climate to the current levels of CO2 in the atmosphere. Best estimates for the transient climate response for a doubling CO2 levels are lower (and depend, of course, on the rate of CO2 increase). Also, without having good estimates for the other contributions to climate forcing during the 20th and early 21st century, such as aerosols, as well as internal climate variability, it is rather difficult to obtain very strong bounds on the estimated climate sensitivity by considering the temperature rise that we have seen over this time. Better estimates are obtained from other events (such as temperatures at the last glacial maximum vs now or response of the atmosphere to the major volcanic eruptions like Mt. Pinatubo).
Citing Venus as an example is laughable. The Venusian atmosphere is hundreds of times denser than ours. This is like arguing that since the armor on an M1A1 tank can protect one from an RPG, a throw pillow should do the same.
J. Peden,
You are missing the obvious explanation that the CO2 travelled back in time to cause the warming. Surely this makes more sense than doubting global warming orthodoxy.
hunter
December 22, 2008 9:09 am
The dead give away that Hansen is full of it is to try and drag Venus in to his claims.
Venus, besides being composed of chemicals similar to Earth, has nothing to do with Earth’s climate. It is much closer to the sun, its rotation is practically nil, it does not have oceans, tectonics, and its atmophere is radically different and always has been. When AGW promoters use Venus as a bogey man to try and induce fear based belief, they are simply demonstrating the lack of proof behind their fear mongering.
foinavon
December 22, 2008 9:13 am
J. Peden,
I’m surprised that you assert that our understanding of the greenhouse effect and the consequences of its amplification include enhanced tropospheric water vapour,… is not happening. That simply doesn’t seem to accord with the science:
A recent experimental study presents further evidence for the water vapour feedback, and supplements a whole slew of studies identifying warming-induced enhancement of tropospheric water vapour (see following citations):
A.E. Dessler et al (2008) Water-vapor climate feedback inferred from climate fluctuations, 2003–2008. Geophys. Res. Lett. 35, L20704,
a summary can be found here: http://www.nasa.gov/topics/earth/features/vapor_warming.html)
see also:
Soden BJ, et al (2005) The radiative signature of upper tropospheric moistening Science 310, 841-844
Santer BD et al. (2007) Identification of human-induced changes in atmospheric moisture content. Proc. Natl. Acad. Sci. USA 104, 15248-15253
Buehler SA (2008) An upper tropospheric humidity data set from operational satellite microwave data. J. Geophys. Res. 113, art #D14110
Brogniez H and Pierrehumbert RT (2007) Intercomparison of tropical tropospheric humidity in GCMs with AMSU-B water vapor data. Geophys. Res. Lett. 34, art #L17912
Gettelman A and Fu, Q. (2008) Observed and simulated upper-tropospheric water vapor feedback . J. Climate 21, 3282-3289
etc. etc….
hunter
December 22, 2008 9:14 am
AGW beleivers, when it is convenient, claim climate reposnes to forcings is swift, but when the evidence that the Earth climate is not radically changing, they make the pitiful dodge that ‘we are not seeing the full effect yet’.
Just like Hansen’s contrivance of climaing that the Antarctic’s continued cooling and ice growth is a proof that it will later warm, this ‘delay’ dodge is just an effort to make the prophecy seem to be reliable.
When Pinatubo or Krakatoa blew, the impact was immediate. If we were seeing someting anywhere close to what Hansen and the IPCC claim, it would alreadybe happening. It is not, so now we get slideshows of grandkids and ohter entertainments as distractions.
Bill Marsh
December 22, 2008 9:26 am
Joel,
“One thing that many people fail to realize is that all functions are locally linear over a small enough range unless you are right at a point of zero slope.”
I don’t consider 118 years (1890 – present) to be a small range? Actually it’s pretty much the entire range so it can’t be ‘small’. Small would be 5-10 years, at least to me.
‘we get that our current concentration of ~385 ppm is 37.5% of the way there whereas if we assume the expected logarithmic relationship, we get that it is 46% of the way there, not that huge a difference.
‘
I’d disagree that it is ‘not that big a difference’, close to a 20% difference is big (46% is ~ 20% larger than 37.5%). Assuming 3C for doubling and accepting the 46% figure, doesn’t that mean that we should have already seen a 1.15 – 1.61C temp increase (and we clearly haven’t seen even the low end of that range). Further if we’ve seen .6C increase (not an accurate figure, it may be lower) over 46% of the range, then doesn’t that mean we might expect to see roughly a 1.3C total increase?
Alan Chappell
December 22, 2008 9:29 am
foinavon
” If ” you are still with us in the New Year, it will be interesting to see what music you are playing.
re George E. Smith 13:00:45 on the fact that CO2 changes lag behind temperature change in the ice-ages record.
Sorry if I failed to explain this to you–isn’t it obvious? The lag is not good news. Rather, it strongly confirms that the Milankovitch-cycle shifts in sunlight over tens of thousands of years regularly initiated a powerful feedback loop. I think essentially everyone agrees that the close of a glacial era comes when solar insolation in mid northern latitudes results in less snow cover in late spring and perhaps early fall, bringing a slight rise of temperature. The long-standing puzzle as to how this slight change could drive a glacial cycle is answered once we understand that the small temperature rise stimulates a substantial increase in gas levels (not only CO2 but also methane, which follows a similar path); this drives the temperature higher, which drives a further rise in the gas levels, and so forth. The process takes quite a few centuries. Ice ages are thus the reverse of our current situation, where humanity is initiating the change, setting the feedback in motion, by adding greenhouse gases — although far faster, and reaching a far higher level, than anything in the Pleistocene record.
foinavon (16:11:33) :
Aren’t the current measures of CO2 from Hawaii close to emission sources, that is, volcanoes?
TonyB
http://meteo.lcd.lu/papers/co2_patterns/co2_patterns.html
This is the report from whence the wind updraft plot comes. Quite recent data.
Higher resolution CO2 and temperature estimates over the last 500 million years can be seen here.
http://upload.wikimedia.org/wikipedia/commons/thumb/f/f5/All_palaeotemps.png/800px-All_palaeotemps.png
http://www.globalwarmingart.com/images/7/76/Phanerozoic_Carbon_Dioxide.png
Will (22:38:48)
I don’t think it’s an “ad hoc assertion”! There’s a lot of data on aerosols and their cooling and warming contributions, and even though the errors associated with quantifying their effects are large, they certainly have to be included in consideration of the historical temperature evolution and future effects.
There’s still a very strong aerosol load apparently, and this is protecting us somewhat against the warming effect of enhanced greenhouse gases. I described some of the data summarised by Carmichael and Ramanathan in their recent review in a post above. HereHere’s the source again:
V. Ramanathan & G. Carmichael (2008) Global and regional climate changes due to black carbon; Nature geoscience 1, 221-227.
Essentially the same data can be accessed from Ramanathan’s testimony before the Wegman oversight committee hearing last year:
http://oversight.house.gov/documents/20071018110734.pdf
Attribution of the contributions from aerosols can be found there. Likewise ice core data can be used to for determining black carbon and sulphurous aerosols in great detail, although the levels in ice cores likely give a localized measure:
J. R. McConnell et al (2007) 20th-Century Industrial Black Carbon Emissions Altered Arctic Climate Forcing. Science 317, 1381 – 1384.
more global scale analysis of emissions and their contributions have come from detailed fuel use statistics and suchlike:
e.g. Novakov T (2003) Large historical changes of fossil-fuel black carbon aerosols, Geophys. Res. lett. 30,, art # 1324
but I suspect these aren’t as precise as we would like, and it’s not an easy subject to quantitate. It does seem to be reasonably well established that the aerosol load is actually substantially greater now than through the 50’s-60’s, but then the greenhouse forcing from excess CO2 during this period wasn’t actually than large either (< 0.3 oC at equilibrium).
Wow Hansen has “nailed it”! I don’t notice any data though, or even an explanation of a logical line of reasoning that doesn’t assume all the effects he is supposed to be measuring?
Hypothesis is not theory, theory is not fact. The burden of proof is supposed to sit squarely on the theory in question.
Computer model runs are not data, corrections to the temperature record also known as WAGs are also not data. I like foinavon waving away all the paleo data. In the past CO2 has clearly not been a major climate driver, nor is it even evident that it is a positive effect despite a prediction based on incorrect assumptions from Arrhenius.
If you think Hansen has any credibility it isn’t because of science. Until he releases his raw data and his methods for doing his calculations the logical conclusion is fraud.
Bill (03:55:54)
re:
Question I have is that if the temperature response to CS (Climate Sensitivity) is logarithmic as Dr Hansen and most seem to agree then why:
1) is the temperature increase primarily linear? Only way that happens I think is if CO2 growth is exponential, yes?
Good question. The temperature response in an ideal world with an instantaneous forcing (e.g. add 386 ppm’s worth of CO2 into the atmosphere as now and then stop and wait to see what happens!) would be something like a hyperbolic rise to a new equilibrium:
e.g. T = Tmax*t/(t+k)
where T is the temperature, Tmax is the temperature at equilibrium that will eventually result from the effect of the forcing, t is time and k is some constant that relates to the intertia in the system.
This should give a hyperbolic change in temperature that tends towards Tmax.
Even within this simple model the temperature change might appear linear since the early parts of a hyperbolic are near linear (t <k). Likewise as you say, the forcing is an ever increasing one since we are continuing to pump CO2 into the atmosphere. This will also tend to make the temperature trend more linear…
2) Given the 2.5 – 3.5C temperature in response to doubling CO2 from 280ppmv and we are currently nearing 400 ppmv (about halfway there) should we not have already seen about 70% of the 2.5-3.5C temp increase?
We can calculate the temperature rise expected within a 3 oc climate sensitivity (CS) (280-400 ppm change) as 1.5 oC, so yes, your value of around 70% is about right. However this is the change expected at equilibrium. It comes back to the inertia in the climate system defined by in the equation just above (in fact there are many different ‘s with different elements of the climate system equilibrating on different timescales). So we don’t expect to get the full “whack” of our current emissions until some decades into the future…
It also seems that the earth’s temperature response to enhanced greenhouse gas concentrations is somewhat suppressed by our aerosol emissions:
see, for example the testimony from V. Ramanathan before the Wegman oversight committee last year which is very informative on the current aerosol science:
http://oversight.house.gov/documents/20071018110734.pdf
foinavon (05:59:16)…
You wrote:
“The Scotese graph with a pseudo-”paleotemperature/paleoCO2 evolution” is also horribly incorrect, but that’s another matter!”
I’m sorry, but the Scotese graph has been corroborated using other proxies (i.e isotopes and iron stained grains) and it is correct. If you read the references at the bottom of the diagram, you would find other authors who have found the same results.
foinavon (05:59:16) :
The Scotese graph with a pseudo-”paleotemperature/paleoCO2 evolution” is also horribly incorrect, but that’s another matter!
You make sweeping comments like this, without any links.
What is the correct ”paleotemperature/paleoCO2 evolution” according to you? Links please.
And here are my links of why the whole caboodle of GCM as presented in the IPCC reports should be considered bad history.
This is the third time I am putting these up on these boards, and I hope the regulars here will excuse me.
A model/theory falls even if one datum disproves it, and there are at least four failures of the projected fits of the models to the data of the last ten years.
1) Temperatures do not follow IPCC projections. Here is a plot to remind this:
http://icecap.us/images/uploads/ipccchart.jpg
2) The fingerprint of CO2 in the tropical troposphere as set out in the AR4 report is absent in the data. Here are the links
for models:
http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter9.pdf
data:
http://icecap.us/images/uploads/GHGModsvsReality.jpg
3) The oceans are cooling instead of warming and setting off a feedback loop of greenhouse warming: http://www.npr.org/templates/story/story.php?storyId=88520025
The spin is: global warming missing heat. The truth is, nature does not follow the GCM IPCC models.
4) the specific humidity is not rising as it should in order to create the runaway feedback loop predicated in the models:
http://www.cdc.noaa.gov/cgi-bin/Timeseries/timeseries.pl?ntype=1&var=Specific+Humidity+(up+to+300mb+only)&level=300&lat1=90&lat2=-90&lon1=-180&lon2=180&iseas=1&mon1=0&mon2=11&iarea=0&typeout=2&Submit=Create+Timeseries
Here are plots of relative humidity, which also falls: http://icecap.us/images/uploads/GlobalRelativeHumidity300_700mb.jpg
The basic premise of the models, that the tiny, (anthropogenic CO2 is a tiny fraction of the CO2 in the atmosphere:
http://www.co2web.info/Icecap_CarbonDioxide.pdf) anthropogenic CO2 is the straw that breaks the camel’s back and starts runaway greenhouse warming is absolutely not supported by the data
In addition there is no driving correlation between the rise in CO2 and global temperatures in this plot: http://icecap.us/images/uploads/Correlation_of_Carbon_Dioxide_with_Temperatures_Negative_Again.pdf
Anthony Watts says:
Since his argument isn’t based on Michael Mann’s paleo results, I don’t see that this message (assuming it to be true…another whole can of worms) is particularly relevant.
Bill Illis says:
Yes, changes in solar insolation kick off the ice albedo changes. However, these changes are in the distribution of solar insolation. The total amount of solar insolation hitting the earth does not change (or not appreciably).
Your calculation includes only CO2. His presumably also includes methane(and maybe NO2?).
Noblesse Oblige says:
Actually, Schwartz has revised his estimate in the reply to the comments on his original paper. His new estimate is something like 1.9 C and has large enough error bars to overlap with a good portion of the IPCC range. (And my guess is some of the commenters on his paper would argue his new estimate is still too low based on the problems they identified in his paper.)
Phil, have you had a bad eperience with “foinavon” in the past? Is that something I might know about?
Yes, my money was on Red Alligator! http://en.wikipedia.org/wiki/Foinavon
My issue with Bill’s data fits is that he treats the baseline [CO2] as one of his parameters, in the latest graph it’s as high as 334ppm
Richard deSousa says:
That is it’s composition now but the question would be what its composition was before the runaway greenhouse effect got going. In particular, all the water on Venus boiled into the atmosphere when it got very hot, dissociated and then I think it eventually escaped into space. It is also worth noting that although nitrogen only makes up ~3.5% of the current Venus atmosphere, this is not a small amount of nitrogen considering that the air pressure on Venus is currently 92X that on earth.
Since Hansen is one of those responsible for understanding the greenhouse effect on Venus, I think he might know a little more about it than you do. (That said, I must admit that I am also surprised to hear him argue that a runaway effect could occur here on Earth, since most scientists that I know of, such as those at RealClimate, argue that a true runaway on Earth is not in the cards. I would like to hear the arguments on both sides.)
“Philip_B (05:50:54) :
Human-made aerosol changes are a forcing, but aerosol changes in response to climate change are a fast feedback.
Oh Boy! A new magic fudge factor.”
You don’t know how right you are. There is strong evidence that aerosols (dust) is a very important factor in the sharp swings between glacial and interglacial climate. What Hansen is trying to do is to claim that GHG is the one important thing and everything else (including aerosols) is feedback. That bit about “fast” feedback, is because dust levels change very quickly in ice-core records when the climate shifts, much faster than the CO2 levels, so for “fast” read “effect before cause”
foinavon, would you perhaps indicate where in your opinion correct paleotemperature/CO2 level curves are to be found?
By the way only the paleotemp curve is due to Scotese, as you would have seen if you had bothered to check. Incidentally the original has rather more detail during the Cenozoic, Anthony selected a simplified version.
OT, but thought it was interesting anyway…
Anyone in New England with access to the cable channel NECN, as part of their 30 minute “news loop”, they are reporting that even though THIS Christmas will be white, Global Warming is threatening to eliminate ALL white Christmases in the future…
They can even tie it into the holidays.
Wonder what Dickens’ Tiny Tim would have thought about that…
JimB
E.M.Smith says:
Hansen explains here that what he gave Rasool was a code to do Mie Scattering calculations. Mie Scattering is something that was worked out around 1900, although the formulas are complicated enough that it would have been a non-trivial task to write code to calculate them back in 1971. (Today, with routines to compute Bessel functions and Legendre Polynomials more readily available, it is much easy to calculate Mie scattering and many people, including myself, have written our own codes.)
To say that Hansen or his model predicted cooling because that is the result that Rasool got is not much different than saying that Newton predicted cooling because Rasool used calculus, invented by Newton, to get his result. (In fact, Newton actually invented, or co-invented, calculus whereas Hansen merely codified the theory already worked out by Mie, so Newton’s connection is more direct.)
It is also worth noting that although the initial paper by Rasool and Schneider in 1971 did predict that cooling due to aerosols would win out over warming due to GHGs, the authors themselves admitted it was a first calculation…and, particularly in response to a comment on their paper, were very clear in noting that their calculation had a variety of potential inaccuracies. Within a few years, Schneider had done further calculations that made him realize that warming would likely win out over cooling. (It is also worth noting that in 1971 it was by no means clear that the U.S. and other Western countries would begin to sharply curtail their emissions of aerosols because of the Clean Air Act and other legislation…and thus that these emissions would not continue to grow exponentially.)
Sorry I forgot the link to Hansen’s explanation: http://www.columbia.edu/~jeh1/mailings/20070924_Grandfather.pdf
As for the other predictions, our understanding of the greenhouse effect and the consequences of its amplification include enhanced tropospheric water vapour,…./foinavon
Which is also not happening so far, consistent with the fact that water vapor alone has not produced the maximal theoretical “greenhouse” effect it otherwise should have, according in part to the very same energy wave absorption mechanism alleged to operate in the case of CO2 [coupled with water vapor’s increasing concentration per atmospheric temperature increase] – an effectively real damping regulation probably due to the operation of climatic mechanisms involving heat energy blocking and dissipation by means of cloud formation, release of latent heat during water vapor precipitation, and convection.
And why these same mechanisms for regulating water vapor’s “ghg” effect would not also work in the case of CO2’s so as to further blunt the alleged large temperature effect from doubling [a small] atmospheric CO2 concentration, is certainly a mystery to me, again especially noting that water vapor concentration is not increasing, but even instead decreasing with increased CO2 concentration.
Moreover, regarding any alleged correlation between CO2 concentrations and temperature over some range of CO2 concentration, if CO2 concentrations follow/lag temperature increases quickly enough, a relevant correlation between them of some significance could be present but not a CO2–> temperature causation. Apparently, previous concentrations of CO2 much higher than those of today have not abetted warming temperatures nor prevented atmospheric temperature decreases.
Pk att says:
No…Eventually, there are forces that come in that stabilize the temperatures. A definition of “runaway” that required such stabilization to never occur and the temperatures to run off to infinity could certainly be proposed but would not be very interesting since such a scenario would never occur. (In particular, I believe you’d be violating the laws of thermodynamics if the temperature of the atmosphere got larger than that of the surface of the sun.) I am not sure if a precise definition has been settled upon but I doubt that any scientist would argue that temperatures rising to the point where all the water in the oceans boils away should not constitute “run away global warming”!
Bill Marsh says:
One thing that many people fail to realize is that all functions are locally linear over a small enough range unless you are right at a point of zero slope. So, over a small enough range, it is difficult to distinguish between logarithmic and linear or between linear and exponential. And, that range is not all that small: For example, if we assume a linear relationship for temperature for CO2 concentrations between 280 and 560 ppm, we get that our current concentration of ~385 ppm is 37.5% of the way there whereas if we assume the expected logarithmic relationship, we get that it is 46% of the way there, not that huge a difference.
I am not sure how you came up with the 70% number. My number of 46% is more accurate. Furthermore, you have to understand that the estimate you quote for a temp increase is the EQUILIBRIUM climate sensitivity…and we are pretty far outside of equilibrium…i.e., we haven’t yet seen the full response of the climate to the current levels of CO2 in the atmosphere. Best estimates for the transient climate response for a doubling CO2 levels are lower (and depend, of course, on the rate of CO2 increase). Also, without having good estimates for the other contributions to climate forcing during the 20th and early 21st century, such as aerosols, as well as internal climate variability, it is rather difficult to obtain very strong bounds on the estimated climate sensitivity by considering the temperature rise that we have seen over this time. Better estimates are obtained from other events (such as temperatures at the last glacial maximum vs now or response of the atmosphere to the major volcanic eruptions like Mt. Pinatubo).
Citing Venus as an example is laughable. The Venusian atmosphere is hundreds of times denser than ours. This is like arguing that since the armor on an M1A1 tank can protect one from an RPG, a throw pillow should do the same.
J. Peden,
You are missing the obvious explanation that the CO2 travelled back in time to cause the warming. Surely this makes more sense than doubting global warming orthodoxy.
The dead give away that Hansen is full of it is to try and drag Venus in to his claims.
Venus, besides being composed of chemicals similar to Earth, has nothing to do with Earth’s climate. It is much closer to the sun, its rotation is practically nil, it does not have oceans, tectonics, and its atmophere is radically different and always has been. When AGW promoters use Venus as a bogey man to try and induce fear based belief, they are simply demonstrating the lack of proof behind their fear mongering.
J. Peden,
I’m surprised that you assert that our understanding of the greenhouse effect and the consequences of its amplification include enhanced tropospheric water vapour,… is not happening. That simply doesn’t seem to accord with the science:
A recent experimental study presents further evidence for the water vapour feedback, and supplements a whole slew of studies identifying warming-induced enhancement of tropospheric water vapour (see following citations):
A.E. Dessler et al (2008) Water-vapor climate feedback inferred from climate fluctuations, 2003–2008. Geophys. Res. Lett. 35, L20704,
a summary can be found here:
http://www.nasa.gov/topics/earth/features/vapor_warming.html)
see also:
Soden BJ, et al (2005) The radiative signature of upper tropospheric moistening Science 310, 841-844
Santer BD et al. (2007) Identification of human-induced changes in atmospheric moisture content. Proc. Natl. Acad. Sci. USA 104, 15248-15253
Buehler SA (2008) An upper tropospheric humidity data set from operational satellite microwave data. J. Geophys. Res. 113, art #D14110
Brogniez H and Pierrehumbert RT (2007) Intercomparison of tropical tropospheric humidity in GCMs with AMSU-B water vapor data. Geophys. Res. Lett. 34, art #L17912
Gettelman A and Fu, Q. (2008) Observed and simulated upper-tropospheric water vapor feedback . J. Climate 21, 3282-3289
etc. etc….
AGW beleivers, when it is convenient, claim climate reposnes to forcings is swift, but when the evidence that the Earth climate is not radically changing, they make the pitiful dodge that ‘we are not seeing the full effect yet’.
Just like Hansen’s contrivance of climaing that the Antarctic’s continued cooling and ice growth is a proof that it will later warm, this ‘delay’ dodge is just an effort to make the prophecy seem to be reliable.
When Pinatubo or Krakatoa blew, the impact was immediate. If we were seeing someting anywhere close to what Hansen and the IPCC claim, it would alreadybe happening. It is not, so now we get slideshows of grandkids and ohter entertainments as distractions.
Joel,
“One thing that many people fail to realize is that all functions are locally linear over a small enough range unless you are right at a point of zero slope.”
I don’t consider 118 years (1890 – present) to be a small range? Actually it’s pretty much the entire range so it can’t be ‘small’. Small would be 5-10 years, at least to me.
‘we get that our current concentration of ~385 ppm is 37.5% of the way there whereas if we assume the expected logarithmic relationship, we get that it is 46% of the way there, not that huge a difference.
‘
I’d disagree that it is ‘not that big a difference’, close to a 20% difference is big (46% is ~ 20% larger than 37.5%). Assuming 3C for doubling and accepting the 46% figure, doesn’t that mean that we should have already seen a 1.15 – 1.61C temp increase (and we clearly haven’t seen even the low end of that range). Further if we’ve seen .6C increase (not an accurate figure, it may be lower) over 46% of the range, then doesn’t that mean we might expect to see roughly a 1.3C total increase?
foinavon
” If ” you are still with us in the New Year, it will be interesting to see what music you are playing.