Marohasy posted this little gem at Curry’s:
“In support of alternative perspectives, and Claes Johnson, I have posted a technical note explaining why we should be sceptical of the Stefan-Boltzmann equation.”
Andrew Hobbssays
Wow. Apparently Curry has decided that she is entitled to her own facts now.
In defense of Judith Curry, she has been very vocal against the whole “slaying the dragon” nonsense which is just a regurgitation of how the greenhouse effect isn’t real, back-radiation is unphysical, etc. Aside from letting them post on her webpage, she is not associated with Jennifer Marohasy or these wild claims about the Stefan-Boltzmann law being untrue.
Arne Melsomsays
I’m a bit puzzled by the title of this thread, as I believe that -in physics- any non-zero value of the tendency term must arise from some kind of forcing. Could you elaborate? Do you mean internal variability, i.e. variability of a system that is not due to forcing external to the system in question?
[Response: This is just a play on words denoting an open thread in which you can discuss any aspect of the science you like. Unforced variations or internal variability are usually just called weather. – gavin]
bratislasays
great, an open thread ! I will be able to ask a layman question at last.
So, I was wondering if it was possible / already done to quantify roughly high latitude heat transfer to the sea with the polar ice cover loss. I explain : since frozen and liquid water are in equilibrium, by measuring the ice loss between two dates you can measure \DeltaQ involved in a global manner – you do not look at particularities, just the global net variation.
This is only an estimate, since you rule out many phenomena (among many things, you consider the high latitudes to be a closed system without any heat transfer in lower latitudes, and you have to get a good measure of sea ice mass loss), but I wondered if anyone tried to do something like that, and how it can improved/ how wrong it is.
Looking forward for a serious answer for this silly question :)
[Response: You can certainly calculate a deltaQ for the ice loss, but it is really small compared to the heat input into the oceans or the variations in heat loss to space. Thus it is not a good constraint on overall heat content changes. Levitus et al (2001) did some basic calculations of this. – gavin]
It’s not written by her, but by an occasional contributor who goes by the handle “cementfriend.”
Some may wish to read it, either
a) to know what some bonehead is mangling out there in the blogosphere, or
b) for the pure entertainment value.
I’m not competent to do a thoroughgoing critique, but I came out with my eyebrows challenging my receding hairline.
Perhaps my favorite tidbit was “To me as an engineer the term albedo is gobbledegook and shows to a large extent the users do not understand heat transfer.”
Some may prefer “However, the concept of back radiation would be in conflict with the second law of thermodynamics.”
But I think you’ll find plenty to choose from, should you be so inclined.
Sorry, make that ‘cementafriend,’ not ‘cementfriend.’
Ray Ladburysays
Chris Colose says, “In defense of Judith Curry,…”
Why?
Andrew Hobbssays
#3 Chris Colose
Oops! A slip of the fingers. I meant ‘apparently Marohasy has decided that she is entitled to her own facts now.’
Sorry about that. (It was past midnight when I posted the comment.)
Adam R.says
So, is a “Venus syndrome” runaway possible on Earth due to fossil fuel use or is it not? Opinion seems divided among credible sources.
Bernsays
#6 Kevin McKinney: thanks for posting those quotes.
I’d like to re-word them, to express my opinion:
“To me, as an engineer who actually studied & got a passing grade in a subject about heat transfer, the term albedo expresses a key factor in absorption of radiative energy from the sun. Also, the concept of back radiation is in complete compliance with the second law of thermodynamics, and those who claim it isn’t have a fundamental lack of understanding of what that law is really saying, not to mention a strange perception of just how radiative heat transfer works”.
“… climate instability was not confined to the last glaciation, but appears also to have been marked during the last interglacial (as explored more fully in a companion paper) and during the previous Saale–Holstein glacial cycle. This is in contrast with the extreme stability of the Holocene, suggesting that recent climate stability may be the exception rather than the rule….” Validity of the temperature reconstruction from water isotopes in ice cores – Jouzel & Dansgaard et al. (1997)
[Response: Careful, these are old papers. The claim made in that early work that the last interglacial was ‘unstable’ was based on the GRIP ice core. The Europeans were a bit too quick to publish these results! When the GISP2 ice core was completed a few months later, it became clear that both cores had disturbed stratigraphy prior to about 100,000 years ago. So the conclusion about the last interglacial was wrong. There is no evidence that the last interglacial, or any interglacial was any more ‘unstable’ than the current one (the Holocene). I do think, however, that the ‘stability’ of the Holocene is itself overblown. That’s another story though.-eric]
The Stefan-Boltzmann comes directly out of statistical mechanics. I apply statistical entropy principles in analyzing oil depletion in the online book “The Oil ConunDrum”. Have a section on CO2 contributions from fossil fuel. This will give the CC skeptics conniptions.
“To me as an engineer the term albedo is gobbledegook and shows to a large extent the users do not understand heat transfer.”
Yikes! To me as an engineer, such statements by others claiming to be engineers are just plain embarrassing. A lot of people claim to be engineers, but I really doubt that this one made the grade.
Adam, we discussed this in the friday round-up thread.
The runaway greenhouse can be triggered in certain astrophysical circumstances where you have a planet with some reservoir of potential greenhouse gas, whether it be a CO2 glacier or an ocean of water. But you need the right stellar or orbital parameters, so CO2 increase alone won’t get us to Venus. I would also point out that there’s other theories for Venus’ evolution aside from a runaway greenhouse, since there’s different ways to get the very deuterium ratio in the water vapor traces on Venus, but I think that it is the best theory out there.
With no greenhouse gases, a planet will increase its emission with temperature as T^4 and this strongly stabilizes the Earth’s climate to change. With a water vapor feedback though, the emission is a bit more linear (you might be able to parametrize it as T^3.9 over some domain for example). If the planet gets warm enough and the optical depth of water vapor is sufficiently deep, the outgoing radiation asymptotes to a horizontal line and becomes decoupled from the surface temperature. What happens is that there’s a mathematical contradiction between the amount of absorbing matter required for sustaining radiative equilibrium and the amount of absorbing matter that preserves the gas-liquid equilibrium.
It is possible for the absorbed solar radiation to exceed this limiting outgoing radiation, in which case the oceans are not stable in liquid form (or condensed CO2 glaciers at the surface must evaporate or sublimate into the atmosphere). The problem with modern Earth is that it’s not close enough to the sun (or the sun luminous enough) to get the absorbed radiation that high. Thus the inner limit of habitability for a planet is set by this threshold of vapor liquid water loss, but for our sun it’s clearly less than the mean Earth-sun distance.
This also depends on the star the planet is near. It’s often assumed the albedo of a planet is solely a characteristic of the planet itself, but it depends very much on the sun’s radiation it receives, and so for different solar types the distance to kick in the water vapor runaway changes, even for the same impinging radiation at the TOA. For Earth, you need over 300 W/m2 of absorbed radiation to kick in a runaway for sure, and we’re safely under that limit.
What is much more likely though is that climate sensitivity is high enough to cause very disruptive socio-economic changes as we continue to add CO2 to the atmosphere.
[Response: I completely agree with Chris here, but will add the caveat that clouds effects interfere with the relatively simple physics of the clear sky case, and make it harder to absolutely rule out a runaway with straightforward basic physics calculations. One can concoct a kind of cloud that would make a runaway possible in Earth’s orbit, but there are very good arguments (as I said in the Roundup thread) that such clouds are implausible, and that cloud feedbacks make it harder, rather than easier, to trigger a true runaway greenhouse. Further, I think that the fact that the massive PETM carbon release did not trigger a runaway is essentially conclusive evidence that cloud feedbacks are not of a type that could trigger a runaway — though the PETM certainly does suggest that some feedback (perhaps clouds) is operating to lead to high climate sensitivity. My flat-out judgment is that I think nobody need lose sleep over the chance of AGW triggering a “Venus syndrome.” –raypierre]
Edward Greischsays
“Of the 54 new planet candidates found in the habitable zone, five are near Earth-sized. The remaining 49 habitable zone candidates range from super-Earth size — up to twice the size of Earth — to larger than Jupiter.” http://www.nasa.gov/home/hqnews/2011/feb/HQ_11-030_Kepler_Update.html
E.T. should have been here by now. E.T. must have exterminated himself by GW. The odds of our survival are very poor indeed.
[Response: Don’t give up hope too soon. We don’t even know if
any of those hab-zone planets have atmospheres, let alone whether there’s CO2 and water vapor in them. The gas/ice giants almost certainly have atmospheres, because gas is the only way to make something so big, but the Earths and Super-Earths could be airless rockballs or iceballs for all we know. –raypierre]
David B. Bensonsays
Chris Colose @16 — Most clear, I think its finally sinking in.
Thank you.
David B. Bensonsays
raypierre @16 — Thanks for the reply.
Instead I’ll lose sleep over droughts interspersed with extreme precipitation events.
dhogazasays
Hank at #16 … god, that’s horrible.
I thought I might read it and come up with a few nuggets to protest against, but the whole is worse than the parts, and can only be appreciated in toto
john byattsays
#21 Drought is relative, it has a number of definitions in Australia and to qualify for drought relief depends on where you live and what you are growing, After a very long drought..{rainfall below a set,average over months not just NO rain} in Victoria that ended in 2010 The wheat farmers were expecting a massive crop only to lose the lot due to flooding from an extreme precipitation event, I think that its called global warming but our politicians say that its crap,
“His book, A “No-Nonsense Guide to Science”,has been published by New Internationalist magazine.”
NO wonder the world doesn’t know what science is all about! In the old days, it would have been phrased: “You don’t bargain with god.”
jyyhsays
#16 Looks like Lou Grinzo is right, ‘climate Pearl Harbor’ is the only thing that MIGHT convince some of those souls of the accuracy of the science in question.
bratislasays
@gavin : many thanks for your answer. I’ll dig that – as soon as I get rid of daily work :)
jyyhsays
#16 “Third, most agreed that there was no scientific basis for the world adopting a target to prevent global warming going above 2 °C. It was “arbitrary”, they said, and cooked up by climate scientists with a political agenda”, is truly funny. Almost so funny I could give up commenting on climate change and the politics that should, could, might, and must happen because of it. Timeframes aren’t very interesting to me within the science, too much to calculate, if you will, though I think I’m physically safe for the rest of my life @ +25m unless there’s a famine. Please delete the prev post.
CMsays
re: Pearce from Lisbon (Hank #16, dhogaza #22)
“whether ocean oscillations (…) could explain the global warming of the past 40 years”
Anyone know that this nugget refers to? The McLean, de Freitas and Carter debacle, or something vaguely real?
MARodgersays
Re the NewScientist article linked @ #16.
This piece contains a few little gems.
“Leaving out the cranks…” It would have been nice to see who they were.
“Few at the meeting doubted that climate change was a real issue that the world had to address, but they said the science had been corrupted.” Herein lies the sole sceptical concession in this piece, the use of the word “but”. As a result, can this mean anything less than ‘The world has to take action on climate change’?
That the meeting was reported without talk of any statement agreed between the climate scientists & sceptics present perhaps demonstrates the event was just nonsense. (Instead we hear the three main ‘totemic’ issues.(i) The “scandalous” adoption of the hockey stick. (ii) What about those ocean oscillations? (iii) And defining 2oC as the safe limit for AGW is both arbitrary and “political”.)
Amid all the time “taken up bitching”, the only question this meeting raises of any merit is surely “What is this piece of so-called journalism doing on the NewScientist website?”
MARodgersays
Re the NewScientist article linked @ #16
The piece contains some little gems. “Leaving out the cranks…” It would have been nice to see who they were.
“Few at the meeting doubted that climate change was a real issue that the world had to address, but they said the science had been corrupted.” Herein lies the sole sceptical concession in this piece, the use of the word “but”. As a result, can this mean anything less than ‘The world has to take action on climate change’?
That the meeting was reported without talk of any statement agreed between the climate scientists & sceptics present perhaps demonstrates the event was just nonsense. (Instead we hear the three main ‘totemic’ issues.(i) The “scandalous” adoption of the hockey stick. (ii) What about those ocean oscillations? (iii) And defining 2oC as the safe limit for AGW is both arbitrary and “political”.)
Amid all the time “taken up bitching”, the only question this meeting raises of any merit is surely “What is this piece of so-called journalism doing on the NewScientist website?”
MARodgersays
Re the NewScientist article linked @ #16
The piece contains some little gems. “Leaving out the cranks…” It would have been nice to see who they were.
“Few at the meeting doubted that climate change was a real issue that the world had to address, but they said the science had been corrupted.” Herein lies the sole sceptical concession in this piece, the use of the word “but”. As a result, can this mean anything less than ‘The world has to take action on climate change’?
That the meeting was reported without talk of any statement agreed between the climate scientists & sceptics present perhaps demonstrates the event was just nonsense. (Instead we hear the three main ‘totemic’ issues.(i) The “scandalous” adoption of the hockey stick. (ii) What about those ocean oscillations? (iii) And defining 2oC as the safe limit for AGW is both arbitrary and “political”.)
Amid all the time “taken up bitching”, the only question this meeting raises of any merit is surely “What is this piece of so-called journalism doing on the NewScientist website?”
Oldfartsays
Can anyone link a list of studies that support the “hockey stick” and/or climate warming? I am a layman involved in fighting off the forces of darkness within my own small area and demand that my demented opponents provide me scientific evidence that anthropomorphic climate warming is not true which, of course they cannot provide. My specious argument on my behalf is that climate warming is “settled science” and that they are the ones making extraordinary claims. However, they occasionally demand peer-reviewed proof of my arguments and I don’t have a handy list stored anywhere. Not asking anyone to do the work, just requesting a bibliography if it already exists.
toxymoronsays
Hi Oldfart,
Lots of places to start with, but I do like Sceptical Science
(http://www.skepticalscience.com/), especially for ‘beginners’.
Ray Ladburysays
Oldfart,
I think the key word you want is “attribution”. For instance, if you type attribution into the RC search box, you get these results”
Also, check out Tamino’s Open Mind blog for excellent statistical analysis and skepticalscience.com for digests of the technical arguments. There are lots more resources out there. If you have specific questions, let us know, and I’ll try to vector you to the right studies.
The thing is that there is a whole mountain range of evidence, temperature trends, energy balance, stratospheric cooling… It isn’t merely rising temperature.
CMsays
#30 (re: “can anyone link a list of studies that support…”)
But that may be a bit more than you bargained for. An update that provides a far shorter, and more reader-friendly overview: http://www.copenhagendiagnosis.com/
Oldfart: http://www.skepticalscience.com/ should provide all the answers you need as well as a means of debunking the most common denier arguments.
Adam R.says
Chris & raypierre:
Thanks for the very useful replies. I will preserve them for the next time someone asks me. It seems the “If it could happen, it probably would have already” answer will do for a quick response. And yes, there is plenty to worry about without boiling oceans in the prospect!
Thanks again for your efforts in this excellent blog.
[Response: Thanks. But a small technical point (of more relevance to those who care about thermodynamics than to those trying to survive in a 100C ocean) — in a runaway greenhoue the oceans do not boil. Boiling happens when the saturation vapor pressure exceeds the local pressure (which is the air pressure, near the surface) in a runaway greenhouse, the added water vapor increase the air pressure enough that you never actually get boiling, which involves forming bubbles in the interior of the fluid. You’re arlready familiar, I’m sure, with the concept that boiling temperature is lower at high altitudes. This is the same thing in reverse, except that you have increased air pressure at sea level instead, by increasing the mass of the atmosphere. You just get evaporation of the ocean sufficient to maintain the atmospheric humidity. –raypierre]
adeladysays
oldfart. If navigating around a site like Skeptical Science seems a bit daunting, go first to the guide. Might be worth printing off a copy and keeping it handy once you’re on top of it.
A subject that perhaps deserves more attention than often awarded is the extent to which future climate change is dependent on the availability of easily extractable fossil fuel reserves. Coal is often estimated at about 900 Gtons, and oil plus gas at probably a smaller figure. The consequences in terms of warming will involve the uncertainties surrounding these estimates, as well as those surrounding climate sensitivity and the probability of tipping points. Nevertheless, each of these elements could be parameterized to create a set of Bayesian priors that might permit a probability range to be estimated. Has this been done? Perhaps the IPCC SRES analyses did some of it, but I haven’t looked into that. Are there other relevant data?
JMsays
Don’t give up hope too soon. We don’t even know if
any of those hab-zone planets have atmospheres, let alone whether there’s CO2 and water vapor in them.
And will they have metallic cores and magnetic fields, or will their local solar winds gradually erode said atmospheres? And then there’s the matter of gravity, which I find to be a matter of taste.
Nope, terra firma is the only place for me, so far.
[Response: As a way of preserving atmospheres, I think magnetic fields are way over-rated. But they’re great if, like me, you prefer your Suunto compass when hiking around Kolmen Valtakunnal Rajapykki, over some fancy battery operated GPS. –raypierre]
Mayasays
“E.T. should have been here by now. E.T. must have exterminated himself by GW. The odds of our survival are very poor indeed.”
It isn’t just the vastness of space that is a barrier to finding E.T., but the vastness of time. Humans are hardly a blip in planetary history; we’d barely make it into the fossil record. Entire intergalactic civilizations could have risen and fallen before mammals even became ascendant on this planet.
So, although I have to agree with you that our odds are not looking very good, I don’t think it’s quite a given that we will exterminate ourselves. Close, but not quite. Civilizations rise and fall, though, and ours is not immune just because it’s technological. The planet has the last say in that, I’m afraid.
David Millersays
OT: apologizes in advance.
I need to animate molecules (multi-atomic, not simple spheres) bouncing around in a cylinder and diffusing through a filter.
Ideally the modeled molecules would have real-world interactions, but the animation doesn’t strictly require it. It does require random linear motion and random rotation. The end result needs to play back on a laptop, but I have no preference between flash, gifs, quicktime, wmv, etc.
If anyone has any suggestions or questions, either post here or email them to me. dmil.rc1 is the name. metheus.org is the domain.
I wonder if anyone can explain this apparent conundrum.
It seems that climate scientists believe that in the next billion years or so the Earth will become so hot it will lose its oceans
“Once the solar luminosity is 10% higher than its current value, the average global surface temperature reaches 320 K (47 °C). The atmosphere will become a humid greenhouse leading to a runaway evaporation of the oceans.[49] At this point, models of the Earth’s future environment demonstrate that the stratosphere would contain increasing levels of water. These water molecules will be broken down through photodissociation by solar ultraviolet radiation, allowing hydrogen to escape the atmosphere. The net result would be a loss of the world’s sea water in about 1.1 billion years from the present”
However. the Earths temperature is said to be related to the 4th root of the suns luminosity. Therefore, the the fourth root of 1.10 is 1.02411369. Applying that to the Earths current temperature of 288K gives 295K.
That is not hugely hot and also seeing as the forecast is for CO2 to fall over the long term, perhaps to much lower than 50 ppm, which would be an effect of minus three doublings of CO2 ie 9K leaving an actual remperature of 286K, which is actually rather cool.
So which bit of the science is correct?
Alan
[Response: The answer is that the fourth power law only applies when the greenhouse gas content of the atmosphere is held constant. The water vapor feedback adds more greenhouse gas to the atmosphere as the climate gets warmer, and leads to more temperature increase. You are thinking well — a 10% increase in luminosity would be not such a big deal if Stefan Boltzmann were the only game in town. The water vapor feedback leads to greater climate sensitivity when you get to very warm climates. All explained with lucidity in Chapter 4 of my book, Principles of Planetary Climate. –raypierre]
You’re ignoring the whole feedback loop which makes the runaway worth talking about!! Water vapor.
The “effective” equilibrium temperature of Earth that balances the absorbed shortwave radiation is 255 K. In general it is the quantity [S(1-a)/σ4]^0.25 where S is the incoming solar radiation at the TOA and ‘a’ is the albedo. “4” is a re-distribution factor that accounts for the spherical geometry of the planet (sometimes it’s better to use something else here; on airless bodies with very large diurnal temperature gradients, averaging over an isothermal sphere is not very meaningful).
If this whole quantity exceeds about 270-280 K on a planet with an ocean, the planet cannot be habitable anymore. Therefore it is a necessary condition that the effective temperature be below about 275 K (though by no means sufficient, this criteria is met on Venus for example).
Oy, look at kind of the sources they rely on:
Source: Oregon Institute of Science and Medicine, “Environmental Effects of Increased Atmospheric Carbon Dioxide,” Journal of American Physicians and Surgeons, Fall 2007
They’ve been building quite a reputation as a reliable source.
I can’t see how.
Pete Dunkelbergsays
What is your baseline for n++? The main page says only 19 comments at this time.
Marohasy posted this little gem at Curry’s:
“In support of alternative perspectives, and Claes Johnson, I have posted a technical note explaining why we should be sceptical of the Stefan-Boltzmann equation.”
Wow. Apparently Curry has decided that she is entitled to her own facts now.
Andrew Hobbs,
In defense of Judith Curry, she has been very vocal against the whole “slaying the dragon” nonsense which is just a regurgitation of how the greenhouse effect isn’t real, back-radiation is unphysical, etc. Aside from letting them post on her webpage, she is not associated with Jennifer Marohasy or these wild claims about the Stefan-Boltzmann law being untrue.
I’m a bit puzzled by the title of this thread, as I believe that -in physics- any non-zero value of the tendency term must arise from some kind of forcing. Could you elaborate? Do you mean internal variability, i.e. variability of a system that is not due to forcing external to the system in question?
[Response: This is just a play on words denoting an open thread in which you can discuss any aspect of the science you like. Unforced variations or internal variability are usually just called weather. – gavin]
great, an open thread ! I will be able to ask a layman question at last.
So, I was wondering if it was possible / already done to quantify roughly high latitude heat transfer to the sea with the polar ice cover loss. I explain : since frozen and liquid water are in equilibrium, by measuring the ice loss between two dates you can measure \DeltaQ involved in a global manner – you do not look at particularities, just the global net variation.
This is only an estimate, since you rule out many phenomena (among many things, you consider the high latitudes to be a closed system without any heat transfer in lower latitudes, and you have to get a good measure of sea ice mass loss), but I wondered if anyone tried to do something like that, and how it can improved/ how wrong it is.
Looking forward for a serious answer for this silly question :)
[Response: You can certainly calculate a deltaQ for the ice loss, but it is really small compared to the heat input into the oceans or the variations in heat loss to space. Thus it is not a good constraint on overall heat content changes. Levitus et al (2001) did some basic calculations of this. – gavin]
The ‘technical note” can be found here:
http://jennifermarohasy.com/blog/2011/02/a-note-on-the-stefan-boltzman-equation/
It’s not written by her, but by an occasional contributor who goes by the handle “cementfriend.”
Some may wish to read it, either
a) to know what some bonehead is mangling out there in the blogosphere, or
b) for the pure entertainment value.
I’m not competent to do a thoroughgoing critique, but I came out with my eyebrows challenging my receding hairline.
Perhaps my favorite tidbit was “To me as an engineer the term albedo is gobbledegook and shows to a large extent the users do not understand heat transfer.”
Some may prefer “However, the concept of back radiation would be in conflict with the second law of thermodynamics.”
But I think you’ll find plenty to choose from, should you be so inclined.
Sorry, make that ‘cementafriend,’ not ‘cementfriend.’
Chris Colose says, “In defense of Judith Curry,…”
Why?
#3 Chris Colose
Oops! A slip of the fingers. I meant ‘apparently Marohasy has decided that she is entitled to her own facts now.’
Sorry about that. (It was past midnight when I posted the comment.)
So, is a “Venus syndrome” runaway possible on Earth due to fossil fuel use or is it not? Opinion seems divided among credible sources.
#6 Kevin McKinney: thanks for posting those quotes.
I’d like to re-word them, to express my opinion:
“To me, as an engineer who actually studied & got a passing grade in a subject about heat transfer, the term albedo expresses a key factor in absorption of radiative energy from the sun. Also, the concept of back radiation is in complete compliance with the second law of thermodynamics, and those who claim it isn’t have a fundamental lack of understanding of what that law is really saying, not to mention a strange perception of just how radiative heat transfer works”.
“… climate instability was not confined to the last glaciation, but appears also to have been marked during the last interglacial (as explored more fully in a companion paper) and during the previous Saale–Holstein glacial cycle. This is in contrast with the extreme stability of the Holocene, suggesting that recent climate stability may be the exception rather than the rule….”
Validity of the temperature reconstruction from water isotopes in ice cores – Jouzel & Dansgaard et al. (1997)
Hat tip to Papers of Willi Dansgaard at http://agwobserver.wordpress.com/
[Response: Careful, these are old papers. The claim made in that early work that the last interglacial was ‘unstable’ was based on the GRIP ice core. The Europeans were a bit too quick to publish these results! When the GISP2 ice core was completed a few months later, it became clear that both cores had disturbed stratigraphy prior to about 100,000 years ago. So the conclusion about the last interglacial was wrong. There is no evidence that the last interglacial, or any interglacial was any more ‘unstable’ than the current one (the Holocene). I do think, however, that the ‘stability’ of the Holocene is itself overblown. That’s another story though.-eric]
The Stefan-Boltzmann comes directly out of statistical mechanics. I apply statistical entropy principles in analyzing oil depletion in the online book “The Oil ConunDrum”. Have a section on CO2 contributions from fossil fuel. This will give the CC skeptics conniptions.
Thank you eric!
“To me as an engineer the term albedo is gobbledegook and shows to a large extent the users do not understand heat transfer.”
Yikes! To me as an engineer, such statements by others claiming to be engineers are just plain embarrassing. A lot of people claim to be engineers, but I really doubt that this one made the grade.
Fred Pearce at New Scientist embarrasses again:
http://www.newscientist.com/blogs/shortsharpscience/2011/02/climate-sceptics-scientists-at.html
Check out the Climate Dogs.
Adam, we discussed this in the friday round-up thread.
The runaway greenhouse can be triggered in certain astrophysical circumstances where you have a planet with some reservoir of potential greenhouse gas, whether it be a CO2 glacier or an ocean of water. But you need the right stellar or orbital parameters, so CO2 increase alone won’t get us to Venus. I would also point out that there’s other theories for Venus’ evolution aside from a runaway greenhouse, since there’s different ways to get the very deuterium ratio in the water vapor traces on Venus, but I think that it is the best theory out there.
With no greenhouse gases, a planet will increase its emission with temperature as T^4 and this strongly stabilizes the Earth’s climate to change. With a water vapor feedback though, the emission is a bit more linear (you might be able to parametrize it as T^3.9 over some domain for example). If the planet gets warm enough and the optical depth of water vapor is sufficiently deep, the outgoing radiation asymptotes to a horizontal line and becomes decoupled from the surface temperature. What happens is that there’s a mathematical contradiction between the amount of absorbing matter required for sustaining radiative equilibrium and the amount of absorbing matter that preserves the gas-liquid equilibrium.
It is possible for the absorbed solar radiation to exceed this limiting outgoing radiation, in which case the oceans are not stable in liquid form (or condensed CO2 glaciers at the surface must evaporate or sublimate into the atmosphere). The problem with modern Earth is that it’s not close enough to the sun (or the sun luminous enough) to get the absorbed radiation that high. Thus the inner limit of habitability for a planet is set by this threshold of vapor liquid water loss, but for our sun it’s clearly less than the mean Earth-sun distance.
This also depends on the star the planet is near. It’s often assumed the albedo of a planet is solely a characteristic of the planet itself, but it depends very much on the sun’s radiation it receives, and so for different solar types the distance to kick in the water vapor runaway changes, even for the same impinging radiation at the TOA. For Earth, you need over 300 W/m2 of absorbed radiation to kick in a runaway for sure, and we’re safely under that limit.
What is much more likely though is that climate sensitivity is high enough to cause very disruptive socio-economic changes as we continue to add CO2 to the atmosphere.
[Response: I completely agree with Chris here, but will add the caveat that clouds effects interfere with the relatively simple physics of the clear sky case, and make it harder to absolutely rule out a runaway with straightforward basic physics calculations. One can concoct a kind of cloud that would make a runaway possible in Earth’s orbit, but there are very good arguments (as I said in the Roundup thread) that such clouds are implausible, and that cloud feedbacks make it harder, rather than easier, to trigger a true runaway greenhouse. Further, I think that the fact that the massive PETM carbon release did not trigger a runaway is essentially conclusive evidence that cloud feedbacks are not of a type that could trigger a runaway — though the PETM certainly does suggest that some feedback (perhaps clouds) is operating to lead to high climate sensitivity. My flat-out judgment is that I think nobody need lose sleep over the chance of AGW triggering a “Venus syndrome.” –raypierre]
“Of the 54 new planet candidates found in the habitable zone, five are near Earth-sized. The remaining 49 habitable zone candidates range from super-Earth size — up to twice the size of Earth — to larger than Jupiter.”
http://www.nasa.gov/home/hqnews/2011/feb/HQ_11-030_Kepler_Update.html
E.T. should have been here by now. E.T. must have exterminated himself by GW. The odds of our survival are very poor indeed.
[Response: Don’t give up hope too soon. We don’t even know if
any of those hab-zone planets have atmospheres, let alone whether there’s CO2 and water vapor in them. The gas/ice giants almost certainly have atmospheres, because gas is the only way to make something so big, but the Earths and Super-Earths could be airless rockballs or iceballs for all we know. –raypierre]
Chris Colose @16 — Most clear, I think its finally sinking in.
Thank you.
raypierre @16 — Thanks for the reply.
Instead I’ll lose sleep over droughts interspersed with extreme precipitation events.
Hank at #16 … god, that’s horrible.
I thought I might read it and come up with a few nuggets to protest against, but the whole is worse than the parts, and can only be appreciated in toto
#21 Drought is relative, it has a number of definitions in Australia and to qualify for drought relief depends on where you live and what you are growing, After a very long drought..{rainfall below a set,average over months not just NO rain} in Victoria that ended in 2010 The wheat farmers were expecting a massive crop only to lose the lot due to flooding from an extreme precipitation event, I think that its called global warming but our politicians say that its crap,
16 & 22 on New Scientist absolute nonsense: Jerry Ravetz an …………….. etcetera etcetera
http://www.sbs.ox.ac.uk/centres/insis/associatefellows/Pages/jerryravetz.aspx
“His book, A “No-Nonsense Guide to Science”,has been published by New Internationalist magazine.”
NO wonder the world doesn’t know what science is all about! In the old days, it would have been phrased: “You don’t bargain with god.”
#16 Looks like Lou Grinzo is right, ‘climate Pearl Harbor’ is the only thing that MIGHT convince some of those souls of the accuracy of the science in question.
@gavin : many thanks for your answer. I’ll dig that – as soon as I get rid of daily work :)
#16 “Third, most agreed that there was no scientific basis for the world adopting a target to prevent global warming going above 2 °C. It was “arbitrary”, they said, and cooked up by climate scientists with a political agenda”, is truly funny. Almost so funny I could give up commenting on climate change and the politics that should, could, might, and must happen because of it. Timeframes aren’t very interesting to me within the science, too much to calculate, if you will, though I think I’m physically safe for the rest of my life @ +25m unless there’s a famine. Please delete the prev post.
re: Pearce from Lisbon (Hank #16, dhogaza #22)
“whether ocean oscillations (…) could explain the global warming of the past 40 years”
Anyone know that this nugget refers to? The McLean, de Freitas and Carter debacle, or something vaguely real?
Re the NewScientist article linked @ #16.
This piece contains a few little gems.
“Leaving out the cranks…” It would have been nice to see who they were.
“Few at the meeting doubted that climate change was a real issue that the world had to address, but they said the science had been corrupted.” Herein lies the sole sceptical concession in this piece, the use of the word “but”. As a result, can this mean anything less than ‘The world has to take action on climate change’?
That the meeting was reported without talk of any statement agreed between the climate scientists & sceptics present perhaps demonstrates the event was just nonsense. (Instead we hear the three main ‘totemic’ issues.(i) The “scandalous” adoption of the hockey stick. (ii) What about those ocean oscillations? (iii) And defining 2oC as the safe limit for AGW is both arbitrary and “political”.)
Amid all the time “taken up bitching”, the only question this meeting raises of any merit is surely “What is this piece of so-called journalism doing on the NewScientist website?”
Re the NewScientist article linked @ #16
The piece contains some little gems. “Leaving out the cranks…” It would have been nice to see who they were.
“Few at the meeting doubted that climate change was a real issue that the world had to address, but they said the science had been corrupted.” Herein lies the sole sceptical concession in this piece, the use of the word “but”. As a result, can this mean anything less than ‘The world has to take action on climate change’?
That the meeting was reported without talk of any statement agreed between the climate scientists & sceptics present perhaps demonstrates the event was just nonsense. (Instead we hear the three main ‘totemic’ issues.(i) The “scandalous” adoption of the hockey stick. (ii) What about those ocean oscillations? (iii) And defining 2oC as the safe limit for AGW is both arbitrary and “political”.)
Amid all the time “taken up bitching”, the only question this meeting raises of any merit is surely “What is this piece of so-called journalism doing on the NewScientist website?”
Re the NewScientist article linked @ #16
The piece contains some little gems. “Leaving out the cranks…” It would have been nice to see who they were.
“Few at the meeting doubted that climate change was a real issue that the world had to address, but they said the science had been corrupted.” Herein lies the sole sceptical concession in this piece, the use of the word “but”. As a result, can this mean anything less than ‘The world has to take action on climate change’?
That the meeting was reported without talk of any statement agreed between the climate scientists & sceptics present perhaps demonstrates the event was just nonsense. (Instead we hear the three main ‘totemic’ issues.(i) The “scandalous” adoption of the hockey stick. (ii) What about those ocean oscillations? (iii) And defining 2oC as the safe limit for AGW is both arbitrary and “political”.)
Amid all the time “taken up bitching”, the only question this meeting raises of any merit is surely “What is this piece of so-called journalism doing on the NewScientist website?”
Can anyone link a list of studies that support the “hockey stick” and/or climate warming? I am a layman involved in fighting off the forces of darkness within my own small area and demand that my demented opponents provide me scientific evidence that anthropomorphic climate warming is not true which, of course they cannot provide. My specious argument on my behalf is that climate warming is “settled science” and that they are the ones making extraordinary claims. However, they occasionally demand peer-reviewed proof of my arguments and I don’t have a handy list stored anywhere. Not asking anyone to do the work, just requesting a bibliography if it already exists.
Hi Oldfart,
Lots of places to start with, but I do like Sceptical Science
(http://www.skepticalscience.com/), especially for ‘beginners’.
Oldfart,
I think the key word you want is “attribution”. For instance, if you type attribution into the RC search box, you get these results”
https://www.realclimate.org/index.php/archives/2011/02/unforced-variations-feb-2011/index.php?s=attribution&qt=&q=attribution+site%3Awww.realclimate.org&cx=009744842749537478185%3Ahwbuiarvsbo&client=google-coop-np&cof=GALT%3A808080%3BGL%3A1%3BDIV%3A34374A%3BVLC%3AAA8610%3BAH%3Aleft%3BBGC%3AFFFFFF%3BLBGC%3AFFFFFF%3BALC%3A66AA55%3BLC%3A66AA55%3BT%3A000000%3BGFNT%3A66A%5CA55%3BGIMP%3A66AA55%3BFORID%3A11%3B&searchdatabase=site#895
Also, check out Tamino’s Open Mind blog for excellent statistical analysis and skepticalscience.com for digests of the technical arguments. There are lots more resources out there. If you have specific questions, let us know, and I’ll try to vector you to the right studies.
The thing is that there is a whole mountain range of evidence, temperature trends, energy balance, stratospheric cooling… It isn’t merely rising temperature.
#30 (re: “can anyone link a list of studies that support…”)
Uh… There’s the IPCC report with more references than you can shake a stick at.
IPCC 4th Assessment Report:
http://www.ipcc.ch/publications_and_data/publications_and_data_reports.shtml
Friendly interface to the references:
http://zvon.org/eco/ipcc/ar4/index.html
But that may be a bit more than you bargained for. An update that provides a far shorter, and more reader-friendly overview:
http://www.copenhagendiagnosis.com/
You can usually rely on skepticalscience.com for bite-sized rebuttals by favorite denier meme, with references to the peer-reviewed literature. E.g.
http://www.skepticalscience.com/broken-hockey-stick.htm
http://www.skepticalscience.com/empirical-evidence-for-global-warming.htm
For further rebuttal resources:
https://www.realclimate.org/wiki
Then come back here for more depth, and for the real debates and uncertainties.
By topic:
https://www.realclimate.org/index.php/archives/2004/12/index/
Hope this helps.
Oldfart: http://www.skepticalscience.com/ should provide all the answers you need as well as a means of debunking the most common denier arguments.
Chris & raypierre:
Thanks for the very useful replies. I will preserve them for the next time someone asks me. It seems the “If it could happen, it probably would have already” answer will do for a quick response. And yes, there is plenty to worry about without boiling oceans in the prospect!
Thanks again for your efforts in this excellent blog.
[Response: Thanks. But a small technical point (of more relevance to those who care about thermodynamics than to those trying to survive in a 100C ocean) — in a runaway greenhoue the oceans do not boil. Boiling happens when the saturation vapor pressure exceeds the local pressure (which is the air pressure, near the surface) in a runaway greenhouse, the added water vapor increase the air pressure enough that you never actually get boiling, which involves forming bubbles in the interior of the fluid. You’re arlready familiar, I’m sure, with the concept that boiling temperature is lower at high altitudes. This is the same thing in reverse, except that you have increased air pressure at sea level instead, by increasing the mass of the atmosphere. You just get evaporation of the ocean sufficient to maintain the atmospheric humidity. –raypierre]
oldfart. If navigating around a site like Skeptical Science seems a bit daunting, go first to the guide. Might be worth printing off a copy and keeping it handy once you’re on top of it.
http://www.skepticalscience.com/The-Scientific-Guide-to-Global-Warming-Skepticism.html
A subject that perhaps deserves more attention than often awarded is the extent to which future climate change is dependent on the availability of easily extractable fossil fuel reserves. Coal is often estimated at about 900 Gtons, and oil plus gas at probably a smaller figure. The consequences in terms of warming will involve the uncertainties surrounding these estimates, as well as those surrounding climate sensitivity and the probability of tipping points. Nevertheless, each of these elements could be parameterized to create a set of Bayesian priors that might permit a probability range to be estimated. Has this been done? Perhaps the IPCC SRES analyses did some of it, but I haven’t looked into that. Are there other relevant data?
Don’t give up hope too soon. We don’t even know if
any of those hab-zone planets have atmospheres, let alone whether there’s CO2 and water vapor in them.
And will they have metallic cores and magnetic fields, or will their local solar winds gradually erode said atmospheres? And then there’s the matter of gravity, which I find to be a matter of taste.
Nope, terra firma is the only place for me, so far.
[Response: As a way of preserving atmospheres, I think magnetic fields are way over-rated. But they’re great if, like me, you prefer your Suunto compass when hiking around Kolmen Valtakunnal Rajapykki, over some fancy battery operated GPS. –raypierre]
“E.T. should have been here by now. E.T. must have exterminated himself by GW. The odds of our survival are very poor indeed.”
It isn’t just the vastness of space that is a barrier to finding E.T., but the vastness of time. Humans are hardly a blip in planetary history; we’d barely make it into the fossil record. Entire intergalactic civilizations could have risen and fallen before mammals even became ascendant on this planet.
So, although I have to agree with you that our odds are not looking very good, I don’t think it’s quite a given that we will exterminate ourselves. Close, but not quite. Civilizations rise and fall, though, and ours is not immune just because it’s technological. The planet has the last say in that, I’m afraid.
OT: apologizes in advance.
I need to animate molecules (multi-atomic, not simple spheres) bouncing around in a cylinder and diffusing through a filter.
Ideally the modeled molecules would have real-world interactions, but the animation doesn’t strictly require it. It does require random linear motion and random rotation. The end result needs to play back on a laptop, but I have no preference between flash, gifs, quicktime, wmv, etc.
If anyone has any suggestions or questions, either post here or email them to me. dmil.rc1 is the name. metheus.org is the domain.
Fred, this isn’t exactly what you’re looking for, but it may help you in your search: http://www.energybulletin.net/primer
I wonder if anyone can explain this apparent conundrum.
It seems that climate scientists believe that in the next billion years or so the Earth will become so hot it will lose its oceans
“Once the solar luminosity is 10% higher than its current value, the average global surface temperature reaches 320 K (47 °C). The atmosphere will become a humid greenhouse leading to a runaway evaporation of the oceans.[49] At this point, models of the Earth’s future environment demonstrate that the stratosphere would contain increasing levels of water. These water molecules will be broken down through photodissociation by solar ultraviolet radiation, allowing hydrogen to escape the atmosphere. The net result would be a loss of the world’s sea water in about 1.1 billion years from the present”
However. the Earths temperature is said to be related to the 4th root of the suns luminosity. Therefore, the the fourth root of 1.10 is 1.02411369. Applying that to the Earths current temperature of 288K gives 295K.
That is not hugely hot and also seeing as the forecast is for CO2 to fall over the long term, perhaps to much lower than 50 ppm, which would be an effect of minus three doublings of CO2 ie 9K leaving an actual remperature of 286K, which is actually rather cool.
So which bit of the science is correct?
Alan
[Response: The answer is that the fourth power law only applies when the greenhouse gas content of the atmosphere is held constant. The water vapor feedback adds more greenhouse gas to the atmosphere as the climate gets warmer, and leads to more temperature increase. You are thinking well — a 10% increase in luminosity would be not such a big deal if Stefan Boltzmann were the only game in town. The water vapor feedback leads to greater climate sensitivity when you get to very warm climates. All explained with lucidity in Chapter 4 of my book, Principles of Planetary Climate. –raypierre]
Oldfart,
Here is a link which lists some articles about the global warming debate.
http://climatechange.procon.org/
Any comment on this (source: http://www.enterstageright.com/archive/articles/0211/0211natclichange.htm ):
[edit – the link is fine]
I’m thinking that journal may not be “prestigious” much longer…
[Response: It’s not new work at all – and it ignores updates to the dataseries. The Gray et al (2010, Rev. Geophys.) paper is far better. – gavin]
Alan Millar,
You’re ignoring the whole feedback loop which makes the runaway worth talking about!! Water vapor.
The “effective” equilibrium temperature of Earth that balances the absorbed shortwave radiation is 255 K. In general it is the quantity [S(1-a)/σ4]^0.25 where S is the incoming solar radiation at the TOA and ‘a’ is the albedo. “4” is a re-distribution factor that accounts for the spherical geometry of the planet (sometimes it’s better to use something else here; on airless bodies with very large diurnal temperature gradients, averaging over an isothermal sphere is not very meaningful).
If this whole quantity exceeds about 270-280 K on a planet with an ocean, the planet cannot be habitable anymore. Therefore it is a necessary condition that the effective temperature be below about 275 K (though by no means sufficient, this criteria is met on Venus for example).
> Dan H.
> procon.org
Riiiight. On one side, science; on the other, Heartland/SEPP, presented equally side by side, as though they were comparable ‘pro’ and ‘con’ sources.
Feh. It’s a source for political material ‘pro’ and ‘con’ for believers who don’t know how to find or understand the science, on many issues.
Look at any issue where you know the science, and see what they’re doing with it. Subtle. Not good.
> climatechange.procon.org
Oy, look at kind of the sources they rely on:
Source: Oregon Institute of Science and Medicine, “Environmental Effects of Increased Atmospheric Carbon Dioxide,” Journal of American Physicians and Surgeons, Fall 2007
They’ve been building quite a reputation as a reliable source.
I can’t see how.
What is your baseline for n++? The main page says only 19 comments at this time.