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 to Will
When you refer to what most of the IPPCC scientist are looking for in response to AGW please add the word negative. As the IPCC takes AGW for granted, they mainly look for negative and often doubtfull effects, and ignore postive effects of increased CO2.
Hugh
December 22, 2008 3:11 am
“Don’t be too proud of this technological terror you’ve constructed. The ability to destroy a planet is insignificant next to the power of the Force.” D. Vader.
Tallbloke
December 22, 2008 3:26 am
Steve: Foinavens value of 3 should be around 2.92 for the figures to work.
Great thread. People actually discussing math and science.
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?
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?
pkatt
December 22, 2008 4:13 am
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? http://solarsystem.nasa.gov/planets/profile.cfm?Object=Venus&Display=OverviewLong
this post by NASA seems to point to dense clouds, high atmospheric pressure and recent extreme global volcanic activity(on a universal timescale). Further it states that Venus holds trapped heat, yet reflects a large portion of the sunlight it gets back into space. For grins a few posts ago I asked if co2 was indeed a warming forcer, why wasn’t it warmer on Mars.. I got the Mars is further from the sun and its atmosphere is thinner explanation. I would like to point out that works both ways folks. Venus is closer to the sun and its atmosphere is denser:)
Sure would be nice to have a scientist in his position that actually had a shred of professionalism or even a pretence of objectivity. He needs to be retired.
I dont remember who posted this site http://earthobservatory.nasa.gov/Features/OceanCooling/
but theres one line in there that says it all ….
‘Since the revision, says Willis, the bumps in the graph have largely disappeared, which means the observations and the models are in much better agreement. “That makes everyone happier,” Willis says.
Happier may not necessarily mean more accurate. Seems funny that the instruments both new and old had to be adjusted to fit the model temps. Seems like theres a lot of that going around, ocean temps, land temps, Ice mass… and yet it continues to get colder as the jet stream slams the northern hemisphere without the aid of La Nina. Dont worry tho, by summer this will be one of the hottest fall-winter seasons on record 😛
Arthur Glass
December 22, 2008 4:51 am
If Mercury has no atmosphere, how can we talk about its ‘climate’?
Dell Hunt, Jackson, Michigan
December 22, 2008 5:02 am
With regards to what I call the “Mysterious Trans-Siberian Heat Wave” that is “driving” global temps up and shown on the GISS map for 2008:
Has anybody looked into calculating the average temp, sans Siberia?
And if it weren’t for this Mysterious heat wave there, where would the global average be?
Interesting that while the rest of the globe has been cooling down, the one place with the least number of actual weather stations, the least reliable past temp history (especially long term), and the coldest land on Earth, outside of Antartica, is the only place thats showing significant warming.
I wonder what the sea ice graph will look like when the great lakes start freezing over? 🙂
foinavon
December 22, 2008 5:13 am
Steve,
Yes, your numbers are right. Within a climate sensitivity of 3oC (of warming per doubled CO2) we expect around 1.3 oC of warming at equilibrium for a CO2 increase from 280-380 ppm.
Of course that’s the equilibrium response. Since the earth has a large inertia (largely from the oceans), it takes some time for the planet to come to a new thermal equilibrium with the forcing. So we still have a bit of warming “in the pipeline” even were CO2 levels to stop dead at current levels.
We’re also still pumping out loads of aerosols and these are protecting us somewhat from the full whack of our greenhouse gas emissions. This has been reviewed recently by Ramanathan and Carmichael, who conclude that the 3 W m-2 excess greenhouse forcing is still being countered by around -1.5 W.m-2 of aerosol cooling.
V. Ramanathan & G. Carmichael (2008) Global and regional climate changes due to black carbon; Nature geoscience 1, 221-227.
That’s a costly paper to get hold of, but Ramanathan has made a detailed presentation of this work to the Wegman oversight committee which can be found here: http://oversight.house.gov/documents/20071018110734.pdf
The papers you cite concerning climate sensitivity are an odd bunch. I couldn’t find this one:
Compo and Sardeshmukh [2008]: Oceans a main driver of climate variability.
Until I realized you’d changed the title! Were you trying to make it sound more interesting?
It’s actually
Compo, G.P., and P.D. Sardeshmukh, 2008: Oceanic influences on recent continental warming. Climate Dynamics, doi: 10.1007/s00382-008-0448-9.
And in fact it’s not particularly controversial. The authors do some modeling and suggest that within their model they can calculate much of the land warming of recent years as a result of ocean warming. They don’t address the cause of the ocean warming, but the evidence is pretty strong that the oceans have warmed due to greenhouse enhancement. Some of the observations of the paper don’t accord with real world observations. For example they question the water vapour feedback to greenhouse warming (which they have eliminated from their model by design), particularly the prediction that the troposphere tends towards a constant relative humidity. However data that identify the predicted change in water vapour feedback and a tendency towards a constant relative humidity has recently been published:
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)
The “paper” by Douglas and Christy is being prepared for a non-science polemical magazine. That’s unlikely to be very helpful!
The Chylek paper seems O.K. I’ll read it when I get a chance…
tty
December 22, 2008 5:20 am
According to Hansen life is just about finished on this planet whatever happens. Ha says on p. 23 that 10-20 Wm-2 is sufficient to cause runaway warming until the oceans boil away. That is about a 1% increase in solar radiation, a figure that will be exceeded in another 100-200 million years.
Mark P
December 22, 2008 5:20 am
Hansen’s Venus comparison is utterly desperate and you’d think somebody working for NASA would actually understand the origins of that planet’s atmosphere. The idea that Venus is an example of ‘runaway greenhouse’ is a common misconception. Venus has always been hot and the reason there is so much carbon dioxide in its atmosphere has nothing to do with volcanic emissions as many people believe.
It all began billions of years ago when Venus and the Earth were much the same; balls of ice and rock. Unfortunately for Venus, its proximity to the Sun meant its ice soon turned to steam and, if there ever were any oceans, they never would have been below boiling point. As the steam reached the upper atmosphere, UV light from the Sun broke the water into hydrogen and oxygen. The hydrogen floated off into space whilst the oxygen sunk back down to the surface and joined with carbon from the super-heated surface rocks thus creating carbon dioxide.
Rather than getting hotter when the CO2 replaced the water vapour, Venus’ surface cooled quite significantly due to it being a much less effective ‘greenhouse’ gas. Venus has only managed to keep its heat due to its incredibly dense atmosphere and extremely slow rotation creating a pressure cooker effect. The atmospheric composition is largely irrelevant. One thing’s for sure though, Venus did NOT heat up as Hansen implies, it just never had a chance to cool down.
JimB
December 22, 2008 5:24 am
PeteM:
Was the article from New Scientist the only one you looked at?…there seems to be other articles that offer a different point of view.
Perhaps they may be of interest…
or not.
“Underground Coal Gasification (UCG) allows access to coal resources not otherwise recoverable and could be used to double or even triple U.S. coal reserves, Julio Friedmann of Lawrence Livermore National Laboratory’s (LLNL) energy and environmental security program” http://findarticles.com/p/articles/mi_hb5712/is_200803/ai_n25285308
JimB
December 22, 2008 5:36 am
“foinavon (14:47:48) :
That’s not really true crosspatch. The fact that enhanced CO2 concentrations result in enhanced warming of the earth has got very little to do with models. It’s the result of a whole load of empirical (and theoretical) analyses.”
Foinavon,
What is the difference between modeling and theoretical analysis?
“In fact the role of CO2 in warming the earth has been known since the middle of the 19th century, and already by the end of the 19th century Arrhenius had established that the earth’s temperature rose as the logarithm of the enhanced CO2 concentration. ”
So 1800s…this was “known”. I think there were quite a few things that were “known” then…but now, maybe not so much.
“There is a whole load of data that bears on the quantitative relationship between enhanced CO2 and enhanced temperature.”
And there’s a whole load of data that doesn’t.
“But it’s the empirical analyses, measurements and so on that inform the models and not the orher way round….”
I agree with this one. I think it’s been proven beyond any question that the models don’t inform the measurements, although some seem to be trying very hard to get them to do exactly that.
“it would be extraordinary to propose that raising atmospheric CO2 levels further (rather dramatically according to the “all the coal and tar shale’s burnt” scenario being discussed on this thread) wouldn’t result in a very large temperature rise”
Based on a 5 minute google of “u.s. coal reserves”, it’s pretty clear to me that there is no “consensus” on how much coal is available, so how is it possible to predict the result of buring it “all”. We have no idea what “all” is.
” Stefan (14:55:53) :
How on earth can so many of these eminent scientists be wrong?
Or are they just human like everyone else?”
There is a part of human nature that makes some people seek data that only supports their belief systems. I don’t know anyone who ever got a “bad deal” buying a car…just ask them.
JimB
Another problem with ‘doubling’ is saturation. A graph appeared many threads back that showed the diminishing return of absorbtion. (can’t remember the name, couldn’t find it) With CO2 somewhere above 97% of everything it can absorb, a doubling might get to 98.5%.
Is that the reason that the curve is a logarithmic one – i.e as the absorption spectra for CO2 gets saturated – CO2 faces a diminishing returns relationship for forcing warming?
Sort of. The IR absorption window _is_ saturated. Further increases in CO2
can only eat away at the margins of the window, slightly widening it. There are probably some effects due to IR photons having a shorter “mean free path” before getting absorbed, but that may be 10s of meters already. (Don’t quote me, I may be wrong!)
N.B. It’s important to keep in mind that the logarithmic relationship is primarily thanks to curve fitting and not theory. If falls down at low levels where the window isn’t saturated, and at high levels where the margins are virtually saturated too.
Cannot help but wonder if some of you folks are related to the creationista/ID folks.
What do ya alls think of comparison of the atmosphere to blood – specifically its function as a buffer? As with blood, it absorbs and absorbs and absorbs until a critical point is reached, whereby it all goes downhill from there.
foinavon
December 22, 2008 5:46 am
kuhncat:
In relation to your comments:
——–
kuhncat (18:33:59) Would you please post the data and models that differ from the IPCC who presented graphs, argument, data, and models showing the infamous HOT SPOT in conjunction with tropospheric cooling and tropopause heightening as the ID of Anthropogenic Global Warming through Greenhouse Gasses??
AR7 is what you must deal with to DENY the hotspot.
I assume you do not agree with the games with models and wind speed measurements to tell us that we can’t EXCLUDE THE POSSIBILITY OF A HOT SPOT??
Personally I am just fine with the IPCC science. They tell us that GG warming will cause the three mentioned data points. We do not have those data points. Therefore we either do not have GG warming (or ANY warming with no hot spot) or they are wrong.
———–
I’m not sure what you mean by “hot spot”. Can you enlighten us? It’s predicted that greenhouse warming will result in particularly strong warming in the high Northern latitudes due to efficient wind and ocean currents that transport excess heat from the equator, coupled with albedo feedbacks. is that what you mean?
As for the other predictions, our understanding of the greenhouse effect and the consequences of its amplification include enhanced tropospheric water vapour, tropospheric warming, stratospheric cooling, an increased height for longwave radiation to space and so on. Each of these has been characterised by real world measurements.
For example one of the many corrections of the early satellite temperature analysis describes the tropospheric warming and stratospheric cooling;
Q. Fu et al. (2004) Contribution of stratospheric cooling to satellite-inferred tropospheric temperature trends Nature 429, 55-58.
A whole load of analysis has characterised enhanced tropospheric water vapour:
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
A.E. Dessler et al (2008) Water-vapor climate feedback inferred from climate fluctuations, 2003–2008. Geophys. Res. Lett. 35, L20704.
There doesn’t seem to be any substantive disagreement between predicted and measured tropospheric temperature trends (‘though accurate tropospheric temperature measurements are still difficult):
B. D. Santer et al. (2008) Consistency of modelled and observed temperature trends in the tropical troposphere. International Journal of Climatology 28, 1703 – 1722.
and so on…
anyway, please give us some clarification with respect to the “hot spot”
JP
December 22, 2008 5:46 am
“It seems Illis is a garage scientist (Links to prof. qualifications appreciated.), so you are probably right. it is so easy to cook a graph, or just get it wrong, or, in the case of the denier folks, get what you are looking for instead of what is. This is why rigorous science is called for: while not perfect, since people aren’t”
The first thing Alarmists resort to is the credentials of those who critique. If that doesn’t work, personal attacks are in order.
How interesting that one of the world’s preminent statisticians (Wegman) is denergenated, and is reduced to a “garage scientists” becuase he failed to toe the line. CCPO, you seem blissfully unaware that Mann’s MBH9X temp reconstructions were nothing more than a statistical analysis of 1300 temp proxies. Those was no “science: involved in crafting the Hockey Stick, as it was purely an excercise in Principle Component Analysis. McIntyre and McKitrick are professional statisticians, and it didn’t take them and many others to find out what Mann was up to. Yet, not one of Mann’s “peers” discovered Mann’s mistakes. So much for Peer Review. Wegman was correct in affixing the label “Social Network” to Climate Science’s peer review process.
BTW, keep a weathered eye on GISS and NOAA’s treatment of December’s Siberian temp anaomalies next month. Should be interesting as Central Siberia has had high temps ranging from -40 to -80 deg F for this month.
Philip_B
December 22, 2008 5:50 am
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.
For those of not inclined to sift through Hansen’s argument. In summary he says,
Aerosols are a cooling forcing roughly half the size of CO2 warming over 20th century (although uncertainty is large and aerosols may be as large as CO2).
Warming causes more water vapour in atmosphere which reduces aerosols and aerosol cooling. Aerosols are therefore a warming (positive) feedback.
Hansen claims aerosol emissions have not reduced. On a global basis he may be right, but aerosols operate locally (mostly) and we know there have been large changes in local aerosol production (Clean Air Acts; Asian industrialization).
The kicker is the overwhelming majority of the sites Hansen uses in his climate network (GISS) are in places where aerosol prodcution has changed substantially (mostly reduced).
Another example of local changes averaged and extrapolated to show a spurious global effect.
foinavon
December 22, 2008 5:59 am
J Peden,
You’re right that the climate sensitivity breaks down at very low [CO2] concnetrations, but these aren’t realistic anyway. Anything below around 100-120 ppm isn’t relevant to CO2 levels during any period in the earth’s history of the last billion years or more (except perhaps during the nasty ice house period(s))!
And of course the climate sensitivity as defined in mine or Bill Illis equations doesn’t give the absolute temperature (mine does since I’ve normalised this to 15 oC at 280 ppm) , but the temperature increase above the blackbody (atmosphere-free) temperature of the earth supplemented with whatever residual warming that would exist in a CO2-free world. So as one continues to halve the CO2 concentration within the climate-sensitivity relationship, the temperature tends towards some horrible cold temperature (around 255K-ish?), rather than continuing to plummet with 3 oC of cooling per halved [CO2]!
The point of my analysis ‘though and the equation that I produced (post at 12:52:53) is to highlight the extremely misleading nature of the Bill Illis curve in the introductory article here.
The Scotese graph with a pseudo-“paleotemperature/paleoCO2 evolution” is also horribly incorrect, but that’s another matter!
foinavon
December 22, 2008 6:01 am
Phil, have you had a bad eperience with “foinavon” in the past? Is that something I might know about? Or did you have an accident on the mountain or something? 😉
Don Keiller
December 22, 2008 6:06 am
Forgive me if this has already been said- I hadn’t time to read Hansen’s opus and all comments.
Am I mistaken in my belief- since Hansen’s ignored it- that ice-age inceptions and terminations have everything to do with solar radiation input at over 65 degrees latitude (Milankovitch cycles) and nothing to do with CO2 (which lags temperature changes by up to 800 years).
So let’s see whether I’ve “nailed it” Looking at slide 8 in Hansen’s lecture (We have good records of the long-lived atmospheric gases from ice cores, covering 400,000 thousand years, even 800,000 years.) there is a temperature change of about 7-8 degrees for roughly a 1.6 increase/decrease in C02, or about 4.5 degrees for a CO2 doubling. Dial in the logarithmic “response” and a few other non-solar “feedbacks” and there you are- about 3.5 degrees/CO2 doubling.
Simple- as long as you ignore the big bright yellow ball in the sky.
Bill Illis
December 22, 2008 6:08 am
Hansen’s presentation (and foinavon) mention Pangini’s high resolution CO2 estimates covering the period from about 16 million years ago to about 45 million years ago.
Hansen used this paper to say CO2 levels should stay below 450 ppm because that is the level Pangini got for the time period when Antarctica glaciated over about 35.5 million years ago.
Except Pangini’s numbers are much higher than this for the time period, as high as 1,500 ppm 34 million years ago.
The CO2 estimates vary greatly over the overall time period including some numbers as low as 181 ppm 16 million years ago (before Greenland glacatiated over.)
Some CO2 enthusiasts might like to look at the actual numbers and see if one can build a CO2-temp correlation from this data. ftp://ftp.ncdc.noaa.gov/pub/data/paleo/climate_forcing/trace_gases/pagani2005co2.txt
re to Will
When you refer to what most of the IPPCC scientist are looking for in response to AGW please add the word negative. As the IPCC takes AGW for granted, they mainly look for negative and often doubtfull effects, and ignore postive effects of increased CO2.
“Don’t be too proud of this technological terror you’ve constructed. The ability to destroy a planet is insignificant next to the power of the Force.” D. Vader.
Steve: Foinavens value of 3 should be around 2.92 for the figures to work.
Guys, It’s the antarctic_temps.AVH1982-2004.jpg you’re looking for.
Great thread. People actually discussing math and science.
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?
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?
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?
http://solarsystem.nasa.gov/planets/profile.cfm?Object=Venus&Display=OverviewLong
this post by NASA seems to point to dense clouds, high atmospheric pressure and recent extreme global volcanic activity(on a universal timescale). Further it states that Venus holds trapped heat, yet reflects a large portion of the sunlight it gets back into space. For grins a few posts ago I asked if co2 was indeed a warming forcer, why wasn’t it warmer on Mars.. I got the Mars is further from the sun and its atmosphere is thinner explanation. I would like to point out that works both ways folks. Venus is closer to the sun and its atmosphere is denser:)
Sure would be nice to have a scientist in his position that actually had a shred of professionalism or even a pretence of objectivity. He needs to be retired.
I dont remember who posted this site http://earthobservatory.nasa.gov/Features/OceanCooling/
but theres one line in there that says it all ….
‘Since the revision, says Willis, the bumps in the graph have largely disappeared, which means the observations and the models are in much better agreement. “That makes everyone happier,” Willis says.
Happier may not necessarily mean more accurate. Seems funny that the instruments both new and old had to be adjusted to fit the model temps. Seems like theres a lot of that going around, ocean temps, land temps, Ice mass… and yet it continues to get colder as the jet stream slams the northern hemisphere without the aid of La Nina. Dont worry tho, by summer this will be one of the hottest fall-winter seasons on record 😛
If Mercury has no atmosphere, how can we talk about its ‘climate’?
With regards to what I call the “Mysterious Trans-Siberian Heat Wave” that is “driving” global temps up and shown on the GISS map for 2008:
Has anybody looked into calculating the average temp, sans Siberia?
And if it weren’t for this Mysterious heat wave there, where would the global average be?
Interesting that while the rest of the globe has been cooling down, the one place with the least number of actual weather stations, the least reliable past temp history (especially long term), and the coldest land on Earth, outside of Antartica, is the only place thats showing significant warming.
All roads lead to Rome…
Earth Observatory
Image of the Day (h/t Steve Goddard)
Visible Earth
I wonder what the sea ice graph will look like when the great lakes start freezing over? 🙂
Steve,
Yes, your numbers are right. Within a climate sensitivity of 3oC (of warming per doubled CO2) we expect around 1.3 oC of warming at equilibrium for a CO2 increase from 280-380 ppm.
Of course that’s the equilibrium response. Since the earth has a large inertia (largely from the oceans), it takes some time for the planet to come to a new thermal equilibrium with the forcing. So we still have a bit of warming “in the pipeline” even were CO2 levels to stop dead at current levels.
We’re also still pumping out loads of aerosols and these are protecting us somewhat from the full whack of our greenhouse gas emissions. This has been reviewed recently by Ramanathan and Carmichael, who conclude that the 3 W m-2 excess greenhouse forcing is still being countered by around -1.5 W.m-2 of aerosol cooling.
V. Ramanathan & G. Carmichael (2008) Global and regional climate changes due to black carbon; Nature geoscience 1, 221-227.
That’s a costly paper to get hold of, but Ramanathan has made a detailed presentation of this work to the Wegman oversight committee which can be found here:
http://oversight.house.gov/documents/20071018110734.pdf
The papers you cite concerning climate sensitivity are an odd bunch. I couldn’t find this one:
Compo and Sardeshmukh [2008]: Oceans a main driver of climate variability.
Until I realized you’d changed the title! Were you trying to make it sound more interesting?
It’s actually
Compo, G.P., and P.D. Sardeshmukh, 2008: Oceanic influences on recent continental warming. Climate Dynamics, doi: 10.1007/s00382-008-0448-9.
And in fact it’s not particularly controversial. The authors do some modeling and suggest that within their model they can calculate much of the land warming of recent years as a result of ocean warming. They don’t address the cause of the ocean warming, but the evidence is pretty strong that the oceans have warmed due to greenhouse enhancement. Some of the observations of the paper don’t accord with real world observations. For example they question the water vapour feedback to greenhouse warming (which they have eliminated from their model by design), particularly the prediction that the troposphere tends towards a constant relative humidity. However data that identify the predicted change in water vapour feedback and a tendency towards a constant relative humidity has recently been published:
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)
The “paper” by Douglas and Christy is being prepared for a non-science polemical magazine. That’s unlikely to be very helpful!
The Chylek paper seems O.K. I’ll read it when I get a chance…
According to Hansen life is just about finished on this planet whatever happens. Ha says on p. 23 that 10-20 Wm-2 is sufficient to cause runaway warming until the oceans boil away. That is about a 1% increase in solar radiation, a figure that will be exceeded in another 100-200 million years.
Hansen’s Venus comparison is utterly desperate and you’d think somebody working for NASA would actually understand the origins of that planet’s atmosphere. The idea that Venus is an example of ‘runaway greenhouse’ is a common misconception. Venus has always been hot and the reason there is so much carbon dioxide in its atmosphere has nothing to do with volcanic emissions as many people believe.
It all began billions of years ago when Venus and the Earth were much the same; balls of ice and rock. Unfortunately for Venus, its proximity to the Sun meant its ice soon turned to steam and, if there ever were any oceans, they never would have been below boiling point. As the steam reached the upper atmosphere, UV light from the Sun broke the water into hydrogen and oxygen. The hydrogen floated off into space whilst the oxygen sunk back down to the surface and joined with carbon from the super-heated surface rocks thus creating carbon dioxide.
Rather than getting hotter when the CO2 replaced the water vapour, Venus’ surface cooled quite significantly due to it being a much less effective ‘greenhouse’ gas. Venus has only managed to keep its heat due to its incredibly dense atmosphere and extremely slow rotation creating a pressure cooker effect. The atmospheric composition is largely irrelevant. One thing’s for sure though, Venus did NOT heat up as Hansen implies, it just never had a chance to cool down.
PeteM:
Was the article from New Scientist the only one you looked at?…there seems to be other articles that offer a different point of view.
Perhaps they may be of interest…
or not.
“Underground Coal Gasification (UCG) allows access to coal resources not otherwise recoverable and could be used to double or even triple U.S. coal reserves, Julio Friedmann of Lawrence Livermore National Laboratory’s (LLNL) energy and environmental security program”
http://findarticles.com/p/articles/mi_hb5712/is_200803/ai_n25285308
“foinavon (14:47:48) :
That’s not really true crosspatch. The fact that enhanced CO2 concentrations result in enhanced warming of the earth has got very little to do with models. It’s the result of a whole load of empirical (and theoretical) analyses.”
Foinavon,
What is the difference between modeling and theoretical analysis?
“In fact the role of CO2 in warming the earth has been known since the middle of the 19th century, and already by the end of the 19th century Arrhenius had established that the earth’s temperature rose as the logarithm of the enhanced CO2 concentration. ”
So 1800s…this was “known”. I think there were quite a few things that were “known” then…but now, maybe not so much.
“There is a whole load of data that bears on the quantitative relationship between enhanced CO2 and enhanced temperature.”
And there’s a whole load of data that doesn’t.
“But it’s the empirical analyses, measurements and so on that inform the models and not the orher way round….”
I agree with this one. I think it’s been proven beyond any question that the models don’t inform the measurements, although some seem to be trying very hard to get them to do exactly that.
“it would be extraordinary to propose that raising atmospheric CO2 levels further (rather dramatically according to the “all the coal and tar shale’s burnt” scenario being discussed on this thread) wouldn’t result in a very large temperature rise”
Based on a 5 minute google of “u.s. coal reserves”, it’s pretty clear to me that there is no “consensus” on how much coal is available, so how is it possible to predict the result of buring it “all”. We have no idea what “all” is.
” Stefan (14:55:53) :
How on earth can so many of these eminent scientists be wrong?
Or are they just human like everyone else?”
There is a part of human nature that makes some people seek data that only supports their belief systems. I don’t know anyone who ever got a “bad deal” buying a car…just ask them.
JimB
Graeme Rodaughan (22:20:35) :
Sort of. The IR absorption window _is_ saturated. Further increases in CO2
can only eat away at the margins of the window, slightly widening it. There are probably some effects due to IR photons having a shorter “mean free path” before getting absorbed, but that may be 10s of meters already. (Don’t quote me, I may be wrong!)
N.B. It’s important to keep in mind that the logarithmic relationship is primarily thanks to curve fitting and not theory. If falls down at low levels where the window isn’t saturated, and at high levels where the margins are virtually saturated too.
Cannot help but wonder if some of you folks are related to the creationista/ID folks.
What do ya alls think of comparison of the atmosphere to blood – specifically its function as a buffer? As with blood, it absorbs and absorbs and absorbs until a critical point is reached, whereby it all goes downhill from there.
kuhncat:
In relation to your comments:
——–
kuhncat (18:33:59)
Would you please post the data and models that differ from the IPCC who presented graphs, argument, data, and models showing the infamous HOT SPOT in conjunction with tropospheric cooling and tropopause heightening as the ID of Anthropogenic Global Warming through Greenhouse Gasses??
AR7 is what you must deal with to DENY the hotspot.
I assume you do not agree with the games with models and wind speed measurements to tell us that we can’t EXCLUDE THE POSSIBILITY OF A HOT SPOT??
Personally I am just fine with the IPCC science. They tell us that GG warming will cause the three mentioned data points. We do not have those data points. Therefore we either do not have GG warming (or ANY warming with no hot spot) or they are wrong.
———–
I’m not sure what you mean by “hot spot”. Can you enlighten us? It’s predicted that greenhouse warming will result in particularly strong warming in the high Northern latitudes due to efficient wind and ocean currents that transport excess heat from the equator, coupled with albedo feedbacks. is that what you mean?
As for the other predictions, our understanding of the greenhouse effect and the consequences of its amplification include enhanced tropospheric water vapour, tropospheric warming, stratospheric cooling, an increased height for longwave radiation to space and so on. Each of these has been characterised by real world measurements.
For example one of the many corrections of the early satellite temperature analysis describes the tropospheric warming and stratospheric cooling;
Q. Fu et al. (2004) Contribution of stratospheric cooling to satellite-inferred tropospheric temperature trends Nature 429, 55-58.
A whole load of analysis has characterised enhanced tropospheric water vapour:
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
A.E. Dessler et al (2008) Water-vapor climate feedback inferred from climate fluctuations, 2003–2008. Geophys. Res. Lett. 35, L20704.
There doesn’t seem to be any substantive disagreement between predicted and measured tropospheric temperature trends (‘though accurate tropospheric temperature measurements are still difficult):
B. D. Santer et al. (2008) Consistency of modelled and observed temperature trends in the tropical troposphere. International Journal of Climatology 28, 1703 – 1722.
and so on…
anyway, please give us some clarification with respect to the “hot spot”
“It seems Illis is a garage scientist (Links to prof. qualifications appreciated.), so you are probably right. it is so easy to cook a graph, or just get it wrong, or, in the case of the denier folks, get what you are looking for instead of what is. This is why rigorous science is called for: while not perfect, since people aren’t”
The first thing Alarmists resort to is the credentials of those who critique. If that doesn’t work, personal attacks are in order.
How interesting that one of the world’s preminent statisticians (Wegman) is denergenated, and is reduced to a “garage scientists” becuase he failed to toe the line. CCPO, you seem blissfully unaware that Mann’s MBH9X temp reconstructions were nothing more than a statistical analysis of 1300 temp proxies. Those was no “science: involved in crafting the Hockey Stick, as it was purely an excercise in Principle Component Analysis. McIntyre and McKitrick are professional statisticians, and it didn’t take them and many others to find out what Mann was up to. Yet, not one of Mann’s “peers” discovered Mann’s mistakes. So much for Peer Review. Wegman was correct in affixing the label “Social Network” to Climate Science’s peer review process.
BTW, keep a weathered eye on GISS and NOAA’s treatment of December’s Siberian temp anaomalies next month. Should be interesting as Central Siberia has had high temps ranging from -40 to -80 deg F for this month.
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.
For those of not inclined to sift through Hansen’s argument. In summary he says,
Aerosols are a cooling forcing roughly half the size of CO2 warming over 20th century (although uncertainty is large and aerosols may be as large as CO2).
Warming causes more water vapour in atmosphere which reduces aerosols and aerosol cooling. Aerosols are therefore a warming (positive) feedback.
Hansen claims aerosol emissions have not reduced. On a global basis he may be right, but aerosols operate locally (mostly) and we know there have been large changes in local aerosol production (Clean Air Acts; Asian industrialization).
The kicker is the overwhelming majority of the sites Hansen uses in his climate network (GISS) are in places where aerosol prodcution has changed substantially (mostly reduced).
Another example of local changes averaged and extrapolated to show a spurious global effect.
J Peden,
You’re right that the climate sensitivity breaks down at very low [CO2] concnetrations, but these aren’t realistic anyway. Anything below around 100-120 ppm isn’t relevant to CO2 levels during any period in the earth’s history of the last billion years or more (except perhaps during the nasty ice house period(s))!
And of course the climate sensitivity as defined in mine or Bill Illis equations doesn’t give the absolute temperature (mine does since I’ve normalised this to 15 oC at 280 ppm) , but the temperature increase above the blackbody (atmosphere-free) temperature of the earth supplemented with whatever residual warming that would exist in a CO2-free world. So as one continues to halve the CO2 concentration within the climate-sensitivity relationship, the temperature tends towards some horrible cold temperature (around 255K-ish?), rather than continuing to plummet with 3 oC of cooling per halved [CO2]!
The point of my analysis ‘though and the equation that I produced (post at 12:52:53) is to highlight the extremely misleading nature of the Bill Illis curve in the introductory article here.
The Scotese graph with a pseudo-“paleotemperature/paleoCO2 evolution” is also horribly incorrect, but that’s another matter!
Phil, have you had a bad eperience with “foinavon” in the past? Is that something I might know about? Or did you have an accident on the mountain or something? 😉
Forgive me if this has already been said- I hadn’t time to read Hansen’s opus and all comments.
Am I mistaken in my belief- since Hansen’s ignored it- that ice-age inceptions and terminations have everything to do with solar radiation input at over 65 degrees latitude (Milankovitch cycles) and nothing to do with CO2 (which lags temperature changes by up to 800 years).
So let’s see whether I’ve “nailed it” Looking at slide 8 in Hansen’s lecture (We have good records of the long-lived atmospheric gases from ice cores, covering 400,000 thousand years, even 800,000 years.) there is a temperature change of about 7-8 degrees for roughly a 1.6 increase/decrease in C02, or about 4.5 degrees for a CO2 doubling. Dial in the logarithmic “response” and a few other non-solar “feedbacks” and there you are- about 3.5 degrees/CO2 doubling.
Simple- as long as you ignore the big bright yellow ball in the sky.
Hansen’s presentation (and foinavon) mention Pangini’s high resolution CO2 estimates covering the period from about 16 million years ago to about 45 million years ago.
Hansen used this paper to say CO2 levels should stay below 450 ppm because that is the level Pangini got for the time period when Antarctica glaciated over about 35.5 million years ago.
Except Pangini’s numbers are much higher than this for the time period, as high as 1,500 ppm 34 million years ago.
The CO2 estimates vary greatly over the overall time period including some numbers as low as 181 ppm 16 million years ago (before Greenland glacatiated over.)
Some CO2 enthusiasts might like to look at the actual numbers and see if one can build a CO2-temp correlation from this data.
ftp://ftp.ncdc.noaa.gov/pub/data/paleo/climate_forcing/trace_gases/pagani2005co2.txt
Sorry, that should say Pagani.