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Venus syndrome – the Claron’s despair

I’ve read deeply on Earth history over the last 30 years of my life — both for personal interest, and as an underpinning of my research and teaching. I first got into science because I wanted to be a palaeontologist (a specialist on past life and evolution in deep time), an interest that traces its origins back to a trip to the British Natural History Museum in London when I was four. The reason I chose to attend Macquarie University, out of the three major options in Sydney (the others were UNSW and U Syd), was because of its flexible palaeobiology curriculum. However, once I’d done a few years of undergraduate studies — majoring in biology, geology, astrophysics and computer science — I became convinced that what I really wanted to be was an analyst and modeller, rather than a field-based ‘rock jock’ who used fossils primarily as geological aids.

Still, my interest in past life, and the proximate and ultimate drivers of extinction, hasn’t diminished. Indeed, it’s been a principal research focus of mine over the last 15 years. Perhaps that’s why I found one particular aspect of Hansen’s book (reviewed on BNC here and here) so fascinating — and so worrisome. I’m talking about chapters 11 and 12, entitled “The Venus Syndrome” and “Storms of my Grandchildren”. For me, it was the stand-out element of the book.

Hansen’s thesis, in brief, is that if we burn all of the available fossil fuels, we run a high risk of setting in train amplifying feedbacks that lead to a runaway greenhouse effect.

How could this happen? Is it plausible? Well, perhaps, perhaps not. The ‘Venus syndrome’ hypothesis has certainly been derided by some, but to me, such blasé attitudes are puzzling, on both philosophical and scientific grounds. But let’s explore the issue a little more, before I offer some opinions.

Hansen first raised this issue in public at the 2008 AGU meeting. To quote from a report on that conference:

“The Venus Syndrome [in which Earth undergoes runaway warming and the oceans boil off] is the greatest threat to humanity’s existence. Earth is Goldilock’s choice of the planets — not too hot, not too cold, it’s just right.”

In the past there have been several periods where temperatures have dropped so low that the planet entered a “Snowball Earth” state, with ice covering the entire surface of the globe. But that slows the process of weathering by rocks and enables carbon dioxide levels to build up in the atmosphere, eventually leading to warming.

According to Hansen, there is no escape from the Venus Syndrome, which could occur for a forcing of 10-20 watts per square metre. For comparison, the net forcing today is between 0 and 3 watts per square metre. Although in the past carbon dioxide levels have reached 4000 parts per million (ppm) without a runaway warming effect, solar irradiance was lower. And today humans are increasing carbon dioxide levels at 2 ppm per year, 10,000 times faster than natural rates, which does not allow time for feedback effects to kick in.

“If we burn all the coal, we might kick in a runaway greenhouse effect, and if we burn all the tar shale and tar sands we definitely will,” said Hansen, who reckons we could decide to leave coal in the ground or use it only with carbon dioxide capture and storage. “We’re going to have to figure out how to power ourselves without it anyhow so why not do it sooner rather than later?”

Global temperature change in a climate model per unit forcing. Data from Hansen et al., "Efficacy of Climate Forcings."

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Here is another excellent description of the idea, from Milan Ilnyckyj:

At one point, Venus had liquid water on its surface. Then, the sun grew brighter and Venus warmed. Its oceans evaporated and huge amounts of carbon dioxide (CO2) got baked out of the crust. The heat made the water break up into hydrogen and oxygen: the oxygen bonded with carbon to make more CO2, and much of the hydrogen escaped into space. Venus became permanently hostile to life, with surface temperatures of 450°C. Could burning all of Earth’s fossil fuels produce the same outcome?

Some people take comfort from the fact that there have been times in the history of the planet when greenhouse gas concentrations were much higher than now. The world was very different, but there was no runaway greenhouse and life endured. James Hansen devotes the entire tenth chapter of Storms of My Grandchildren to considering whether thisassessment is valid. Three things give him pause:

1. The sun is brighter now than it was during past periods with very high greenhouse gas concentrations. The 2% additional brightness corresponds to a forcing of about 4 watts per square metre and is akin to a doubling of CO2 concentrations.

2. For various reasons, the greenhouse gas concentrations in past hot periods may not have been as high as we thought.

3. We are introducing greenhouse gases into the atmosphere far more quickly than natural processes ever did. This might cause fast (positive) feedback effects to manifest themselves forcefully, before slower (negative) feedback effects can get going.

He also explains that the sharp warming that took place during the Paleocene–Eocene Thermal Maximum (PETM) were not caused by fossil fuels (which remained underground), but rather by the release of methane from permafrost and clathrates. If human emissions warm the planet enough to release that methane again, it could add a PETM-level warming on top of the warming caused by human beings.

Hansen’s conclusions are, frankly, terrifying:

The paleoclimate record does not provide a case with a climate forcing of the magnitude and speed that will occur if fossil fuels are all burned. Models are nowhere near the stage at which they can predict reliably when major ice sheet disintegration will begin. Nor can we say how close we are to methane hydrate instability. But these are questions of when, not if. If we burn all the fossil fuels, the ice sheets almost surely will melt entirely, with the final sea level rise about 75 meters (250 feet), with most of that possibly occurring within a time scale of centuries. Methane hydrates are likely to be more extensive and vulnerable now than they were in the early Cenozoic. It is difficult to imagine how the methane clathrates could survive, once the ocean has had time to warm. In that event a PETM-like warming could be added on top of the fossil fuel warming. After the ice is gone, would Earth proceed to the Venus syndrome, a runaway greenhouse effect that would destroy all life on the planet, perhaps permanently? While that is difficult to say based on present information, I’ve come to conclude that if we burn all reserves of oil, gas, and coal, there is a substantial chance we will initiate the runaway greenhouse. If we also burn the tar sands and tar shale, I believe the Venus syndrome is a dead certainty.

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My favourite part of the book is that which follows the dry scientific description of the Venus Syndrome. Hansen presents a short ‘science fiction’ story — a parable, if you will, centred around  a sentient alien species called the Claron. Having detected early TV transmissions from the mid-20th century, the Claron arrive (after a supreme technological feat) at Earth, sometime after the year 2500. However, instead of encountering a verdant blue-green planet, flourishing with life and civilisation, they find a lifeless dust bowl with a blistering surface temperature exceeding 100 degrees Celsius – above the boiling point of water. After working out what must have gone wrong (‘carbocide’), the story story concludes with an act reminiscent of Charlton Heston on the beach, as he shook his fist at the half-buried Statue of Liberty (“Damn you all to hell!). The despairing Claron pilot, having left his companions at an abandoned 21st century Martian base, returns to Earth and plunges his craft into the baking hell hole that was once known as Washington DC.

[Do yourself a favour and read the whole short story, which goes for about 10 pages].

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My closing point is this: There is absolutely no certainty that human action will trigger positive Earth system feedbacks to the extent that all life is eliminated, forever… yet we cannot categorically rule it out. The Venus Syndrome is an unquantifiable and unprovable hypothesis, supported only by a logical — but ultimately subjective — interpretation of the messages of climate past. Hansen might very well has misread the palaeoclimate tea leaves, and those folks who confidently declare it to be nothing more than ‘alarmist speculation’ might well be right. But what if they’re not right? Or what if there’s even a 1% chance that they’re not?  (My interpretation of the science is that the odds are ‘better’ than 1%, and when we’re talking about the Venus Syndrome, that’s not comforting). It is nothing short of gross cognitive dissonance to unequivocally disregard this possibility and yet still claim that you give a damn about future generations, especially when (i) we know we have to move beyond fossil fuels at some future point in our civilisation, and (ii) we have already developed the technology to fully enable this transition.

It’s time for some rational risk management, folks.

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By Barry Brook

Barry Brook is an ARC Laureate Fellow and Chair of Environmental Sustainability at the University of Tasmania. He researches global change, ecology and energy.

218 replies on “Venus syndrome – the Claron’s despair”

…..”Furthermore, the upper clouds are marked by areas visible in the ultraviolet light that mysteriously absorb half of the whole solar energy received by the planet.

The mysterious ultraviolet absorber has been known of for decades.

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but we still don’t understand it – right!

I doubt anyone credible is claiming that we have a complete understanding of any planet’s climate system, including the one we live on. This doesn’t alter the widely understood basics of climatology.

It seems that anti-AGW people will latch on to anything which undermines the case for global warming, even if it is taken out of context, even if the interpretation is doubtful, and for that matter, even if the factoid being touted is in direct contradiction to the the last such factoid they paraded about.

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Barry, the simple answer is that the surface temperatures on Venus aren’t caused by the greenhouse effect. Remember that most of the greenhouse warming on Earth is caused by water vapor, not CO2. The atmosphere of Venus is 90 times thicker than Earth’s and the percentage of CO2 is hundreds of times greater than earths, so we are talking about 2^13th more CO2 on Venus, but the water vapor is only available in trace amounts. Without the feedback from the water vapor, the direct forcing from CO2 is less than 1 degree per doubling, so the actual CO2 greenhouse effect on Venus is actually less than Water Vapor + CO2 on Earth. The reason Venus is so hot is because the atmosphere is so thick. If our atmosphere was a thick as Venus, then we would be a boiling hot hell also. Here is a post I read with some more math.

http://www.buzzle.com/articles/how-hot-is-venus.html

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Joel, the Venusian atmosphere is so thick because its water oceans boiled away long ago due to a runaway greenhouse effect, after which its hydrogen was subsequently lost to space, and the oxygen scavenged carbon from the surface to form an atmosphere composed mostly of CO2. Without the runaway greenhouse effect, driven by water vapour (initially), Venus would not look the way it does today. I suggest you take the time to read Hansen’s book, reference in the lead post of this comment thread, if you want an explanation on this matter from a scientist who did his PhD on the atmosphere of Venus – this has allowed him to give a very lucid and clearly argued explanation of what went on.

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Barry Brook, on 12 May 2010,
I hope you will not mind me commenting on the Venus question you asked Joel. The science is beginning to make some kind of sense to me but I must confess I am a physicist rather than a climate scientist.

According to Soden and Held, 2000. (http://www.gfdl.noaa.gov/bibliography/related_files/annrev00.pdf) the Earth has an effective radiative temperature of 255 Kelvin owing to radiative layers at an average height of ~5 km. The radiation lost to space from these layers is in balance with the incoming radiation from the sun.

The average temperature at the Earth’s surface is 288 K which is 33 K warmer than the radiating layers. The temperature gradient to the ground is therefore approximately 6.6 Kelvin/km which is consistent with the measured adiabatic lapse rate which varies between 5 and 10 degrees Kelvin/km according to the local water vapour content.

For a more detailed explanation, please look at:
http://www.countingcats.com/?p=4745

Applying the same idea to Venus, after adjusting for the planet’s albedo the mean radiative temperature is 288 Kelvin and this temperature occurs at a height of ~50 km. See “Temperatures within Venus’s atmosphere”, Jenkins 1995:

Venus’ surface temperature is at ~ 733 Kelvin, 450 K hotter than the radiative equilibrium layers. This requires an adiabatic lapse rate of 9 Kelvin/km which is in reasonable agreement with the calculated (dry) rate of 10.5 Kelvin/km.

The high temperatures on Venus appear to be inevitable given that the planet has a much thicker atmosphere than Earth has. There is absolutely no need to invent a “Runaway Greenhouse Effect” to explain what has been measured.

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the mean radiative temperature is 288 Kelvin and this temperature occurs at a height of ~50 km.

If there were no greenhouse effect, wouldn’t the mean radiative temperature be the same as the surface temperature?

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@ Finrod

The anti-AGW people see through the “Wicked” problem that climate change is represented as a conventional environmental ‘problem’ that is capable of being ‘solved’. The use of a ‘deficit model’ of science hasn’t helped the cause either.

Maybe a little read over the Hartwell Paper will help loosen you up.

Click to access HartwellPaper_English_version.pdf

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So Gordon, what do you think? If a planet’s atmosphere has no greenhouse effect, ie, it’s completely transparent to all wavelengths, shouldn’t the radiative temperature and the surface temperature be identical?

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Finrod,
The “Greenhouse Effect” works by preventing the relatively warm surface of a planet from radiating directly to space. This has favourable consequences for Earth by causing a warming of roughly 33 degrees Kelvin.

As mentioned in an earlier post, if the radiative layers were at the same temperature as the surface there would be no warming effect at all.

Unfortunately for Venus the atmosphere is much thicker so the warming effect is inconveniently large at over 400 degrees Kelvin.

Gordon,
The Hartwell paper is a good read. I was surprised to see the word “sinful” used in the context of climate science! Although this think tank makes many excellent points they still come out in favour of a carbon tax, albeit a low one.

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So if the Venus terraforming lobby eventually get their way and a parasol is placed between the Sun and Venus in order to cut off sunlight to reduce the planet’s temperature, what do people think is going to happen? Will the temperature of Venus’ atmosphere and surface drop, or will it remain as it is because of the grat thickness and pressure of the atmosphere?

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@ Finrod:
Nice logical questioning sequence there, but don’t expect any answers. In a moment Gordon will point and shout “Look, bright shiny thing over there!” and link to something completely unrelated.

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As a matter of fact, assume all possible sources of heating except the sunlight (which has been cut off) to be at average levels which have established the long-term equilibrium.

So do tell us what you think will happen then.

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Well that depends on whether you believe that Venus is heated by a super greenhouse effect or it is still cooling from a celestrial event. In the case of the former it would cool quickly to -? K and in the case of the latter – cool slowly over a long period.

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I’m guessing that unless there is some left over radioactive heat at the core, like our own planet, it would quickly cool back to the background average level of interstellar objects.

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Well that depends on whether you believe that Venus is heated by a super greenhouse effect or it is still cooling from a celestrial event.

I’m interested in what you think would happen.

Are you implying, Gordon, that you’re a closet Velokovsyist?

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Mmmmm…. I can’t see where Velikovskyist proposed a theory for Venus’s retrograde rotation. Can you?

I expect you’re creative enough to dream something up. Now, what do you think would happen in my thought experiment?

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I defend the scientific consensus against denialists, so, coherently, I also defend it “against” individual climate scientists: I don’t think there is any peer-reviewed document supporting this notion that a Venus-like runaway feedback could possibly happen to the Earth.

Rasmus Benestad and Ray Pierrehumbert put this same idea across at realclimate.org: “Is there a risk that anthropogenic global warming could kick the Earth into a runaway greenhouse state? Almost certainly not”. They argue that 375 W/m2 would be needed, instead of the 10-20 W/m2 suggested by Hansen:
http://www.realclimate.org/index.php/archives/2006/04/lessons-from-venus/

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He dropped by my blog last night to spray some meaningless dribble… he’s all out of ideas I’m afraid. I’m not even a scientist and I could see where this was going. I think he’s realised his mistake.

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@ Finrod

Venus has:

1. A negligable magnetic field
2. An equatorial rotation of 6.5 km/h
3. Subduction that occurs on an enormous scale, completely recycling the crust every 100 M years.

But somehow think that Venus was once earth like!

Maybe it would be better if you focused on Mars – at least there is evidence that life once existed there.

@ Eclipsenow

Chirp..chirp…chirp…….(crickets in background)

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Maybe it would be better if you focused on Mars – at least there is evidence that life once existed there.

But the prize, Gordon… the prize! What you and Joel and GallopingCamel have done is describe a planetary-scale overunity device. I want to know how this process works, and if it can be artificially engineered for power production. Come on now, you owe it to humanity to tell us everything you know about this wonderful new paradigm.

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No Finrod, then energy is created from latent heat. If the Earth subducted like Venus what temperature do you think we would be sitting at ? Your theory hinges on everything being in balance but by your own admission science does not fully understand the processes operating on Venus let alone whether they are in balance.

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Will do Barry.

I enjoyed your ABC 702 interview, but would have liked it to run a little longer and get a bit ‘meatier’. It was good that both you and Ian seemed to agree on the urgency, and were even kind enough to argue one another’s positions a little… such as when Ian argued that a Chernobyl event was extremely unlikely because they basically sabotaged their own plant! I thought that was a strong word for an anti-nuclear activist to use.

I liked the humour at the beginning when James described it as a ‘dry’ read and you laughed and hammed up being defensive and said “Er, I thought it was very entertaining!” Humour on a fairly technical topic like this goes down well.

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I’m going to wind up my comments on this matter with this observation: High pressure and a thick atmosphere does not by itself force high temperatures. Venus’ cloud cover already acts as a pretty effective planetary parasol, and the heat balance is maintained at it’s current high temperature by virtue af it’s massive greenhouse increment, which results mainly from its enormous CO2 atmosphere, with a bit extra thrown in from the small water vapour content still present, which neatly blocks off another part of the em spectrum. If there were no greenhouse effect,. the surface temperature would be about that of Mars (due to the high albedo).

My line of questioning was intended to highlight the logical absurdities in the claim that high pressure alone would result in ongoing high temperatures. go down that path and you cannot avoid asssumptions which lead to violations of thermodynamics (nor generally held to be a good sign for a dcientific hypothesis).

For those who are interested, if a parasol system were to completely shade Venus, it would take a bit over 200 years for the CO2 component of the atmosphere to freeze out on the surface (although there is so much N2 present that the atmopshere would still be thicker than Earth’s, to the extent that explorers would have to guard against nitrogen narcossis).

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Just imagine what you could do if you covered this futurist parasol with nano-pv spray and beamed the microwaves into receiver dishes strategically placed around Venus…

(This is no slight against nuclear power, which seems to be the most economical way to move forward, but just brainstorming future scenarios based on a Venus terraforming project. Off topic, so I guess it ends here.)

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Barry, I’ve reserved the Hansen book at the library and I’ll check a branch near my house that might have a copy on the shelf. It doesn’t appear to technical based on what it shows in Amazon. What technical references does Hansen cite on Venus? I assume he doesn’t actually the actual math in this book.

BTW, my favorite explanation on greenhouse warming is here: http://brneurosci.org/co2.html

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So Hansen claims Earth did not previously “go Venusian” when CO2 was 4,000 ppm because solar irradiance was 4W/m² lower at that time. That doesn’t even pass the smell test.

Total solar irradiance of the Earth varies between 1,412 W/m² in January to 1,321 W/m² in July. So the natural variation within a single year is 22 times the deficit that supposedly previously saved the Earth from its fiery Venusian fate.

Or to put it another way, do you really believe the Earth’s thermodynamics are on such a hair-trigger than a 4W/m² increase in irradiance out of 1400 4W/m² would cause runaway greenhouse, yet the 91W/m² change from July to January has almost no measurable effect?

This is why climate science has zero credibility.

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Total solar irradiance of the Earth varies between 1,412 W/m² in January to 1,321 W/m² in July

No, it didn’t. It varied between 1365.25 and 1365.5 W/m2 between January to July, which is 1/16 of 4 W/m2 forcing, not 22 times. You are wrong by considerably more than 2 orders of magnitude.

That’s why fly-by-night commenters like you have zero credibility, ‘libertarian’. This is a science blog, not a place for fairy stories.

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Pffft. I’m no scientist, but I can see some wonkiness here. Accepting your data for the moment (and I note you don’t quote any sources) you’re talking about shorter term seasonal averages within the natural variation.

What if that natural variation were 4W/m2 lower than today?

Wonkitated ‘logic’ like this is why even us laymen scoff at Denialist claims. It’s like some Denialist loony pointing at the Arctic ice regrowing every winter, and saying “Look at all the ice growing!” Yeah. But what about the accumulated multi-year ice, the thickness of the ice, the bigger picture, and what will happen to seawater temperatures each year as the summer sun belts down straight into ice-free water?

You carrying on about seasonal variation ignores the difference a mere 4W/m2 can have if it is 4W/m2 higher across that seasonal variation. (So, for argument’s sake, January was 1408 and July was 1317 in geological time ago).

But, “Look at all the ice regrowing!” ;-)

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And I of course defer to Barry’s temperature expertise here. My whole exercise was just to highlight some of the logical fallacies in the way they use the data, let alone the fact that you Denialists so often get the data wrong in the first place!

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No, it didn’t. It varied between 1365.25 and 1365.5 W/m2 between January to July,

They must be seasonally adjusted figures. Think about it for a minute Barry. The Earth’s orbit is not circular – closest point to the sun (perihelion) is about 147.1 Gm, farthest point (aphelion) is about 152.1 Gm.

To first order, the relative change in insolation from perihelion to aphelion is the ratio between the surface areas of the spheres at those radii, or 147.1^2 / 152.1^2 = 0.935. So just by simple geometry the total insolation varies by 6.5%, which is almost exactly the figure I quoted (6.5% = 91/1400).

Like I said: climate science has zero credibility.

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Yes, they are seasonally adjusted figures, which is what is relevant for assessing a trend in TSI due to changes in the physical conditions of the sun. But I understand what you seem to be arguing now — because the Southern Hemisphere summers are hotter than the Northern Hemisphere summers, due to orbital eccentricity, any additional and year-round forcing from increased GHG cannot be relevant to climate, nor drive climate change. I had misinterpreted the intent of your statement, as it never occurred to me that someone might seriously be arguing that the existence of this natural component of seasonal-hemispherical climate variability axiomatically renders human-caused (or any other externally driven) global climate change as irrelevant/impossible, as you seem to be implying.

Think about that logical train of thought for a while. How, for instance, does natural orbital eccentricity change the simple conclusion of a net planetary energy imbalance due to the additional GHG forcing (or any other new forcing)? How does one explain the glacial-interglacial cycles, if such small forcings, exerted year in, year out, are irrelevant? Indeed, on this basis, how did climate ever change naturally in the past, other than via the predictable long-term shifts in eccentricity on a ~50 kyr semi-amplitude?

Further, from you statement “climate science has zero credibility”, are you implying that climate scientists have not thought of this, or that this is not accounted for? Or are you suggesting that this very basic fact is ignored, or miscalculated, in climatology? What is the credibility problem of which you speak?

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barry: does the variance in libertarian’s numbers (1321-1412 w/m2) refer to the “natural component of seasonal-hemispherical climate variability?”

are the two sets of numbers then consistent? (1365.25 to 1365.5 w/m2 averaged over the globe from jan to july)

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Barry & libertarian,
It seems you are both right so this may be a “failure to communicate” (as in Cool Hand Luke).

The measured eccentricity in Earth’s orbit is 0.0167 and the orbit major axis is currently 299.2 Gm. The corresponding perihelion and aphelion distances are therefore approximately 152.1 and 147.1 Gm as stated by libertarian.

The mean Total Solar Irradiance is ~1,366 W/sq. meter so each year the TSI oscillates between 1,412 and 1,321 W/sq. meter (91 W/sq. meter or ~6.4% range).

Barry appears to be quoting the long term average TSI that varies by less than 0.25% and therefore cannot account for the observed correlation between solar activity and global temperature.

I have to thank you guys for forcing me to think and then look for ways to figure out how smart people can disagree on matters of basic science.

The huge variation in TSI each year seems to favor the arguments of Roy Spencer and Richard Lindzen who suggest that Earth’s climate is relatively insensitive to radiative forcing owing to negative feedbacks (f~ -0.3).

The climate models used by the IPCC all assume positive feedback coefficients which should amplify the annual temperature variations.

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I had misinterpreted the intent of your statement,

I call revisionist BS Barry. My statement was perfectly clear:

Total solar irradiance of the Earth varies between 1,412 W/m² in January to 1,321 W/m² in July.

That makes little sense as a “seasonally adjusted” statement since it is discussing precisely the variance in insolation between January and July, which are when the Earth is at its extremal positions relative to the sun. (I am using “seasonally adjusted” in the general economic sense; the insolation variation due to the radius change does not cause the seasons as its effect is overwhelmed by the change in insolation due to the Earth’s tilt.)

that the existence of this natural component of seasonal-hemispherical climate variability axiomatically renders human-caused (or any other externally driven) global climate change as irrelevant/impossible,

This is more revisionist BS. I wasn’t claiming that climate change is impossible, just that Hansen’s argument that we should derive no comfort from 4000ppm CO2 in the past because the sun was 4W/m2 dimmer is bogus:

Or to put it another way, do you really believe the Earth’s thermodynamics are on such a hair-trigger that a 4W/m² increase in irradiance out of 1400W/m² would cause runaway greenhouse, yet the 91W/m² change from July to January has almost no measurable effect?

Sure, a 4W/m2 change can have a long-term moderate effect. But it is simply not plausible that a system averaging 1400W/m2 with intra-annual changes of nearly 100W/m2 has previously been saved from Venusian tragedy by a mere 4W/m2.

This kind of extreme global warming alarmism requires at root an unrealistically sensitive climate system. If the Earth was indeed such a system we wouldn’t be here today to discuss it. Hansen should know this. You should know it too Barry. If either of you are representative of the state of the science, then I stand by my claim: climate science has zero credibility.

(ok, it has some, but those with crediblity need to start denouncing this kind of BS rather than promoting it).

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So because I couldn’t conceive that you could be so naive (to use a euphemism) as to equate natural, unforced annual cyclic change with a forced, cumulative change, you now think it’s revisionist BS. Right… Meanwhile, from you, a 4 W/m2 now would have a ‘moderate effect’ and you’re suddenly happy to start talking about the concept of climate sensitivity — you sure changed your tune. And then you ignore (forgot?) feedbacks, and imply that Hansen says 4W/m2 would be it. Take another peek at the chart shown in this post, and add up the cumulative forcing as forcing continues to double with methane release, albedo changes and other feedbacks (including, at the very end, an evaporated ocean).

But you know what? This latest exchange has reminded me why I try not to get into such arguments in the first place; I thought I was well over trying to ‘debate’ this really fundamental stuff. I tip my hat to you for drawing me into a pointless activity that I’d long ago vowed never again to engage in. I appreciate it when commenters like gallopingcamel say that they enjoy an intelligent debate, but when one ‘opponent’ liberally throws around words like ‘BS’ and dismissals like ‘zero credibility’, I have to say that sorry, I’m just not interested in it. As such, I’ll be more strict with the use of my mental ‘ignore’ button in future, and I should have been in this instance.

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This thread started out discussing the high surface temperature on Venus. One hypothesis is that the high temperature would not be possible without the thick atmosphere that supports a huge temperature differential owing to convective layers with an adiabatic lapse rate of ~10 degree Kelvin/km. Given the 97% CO2 atmosphere and sulphuric acid clouds at ~50 km one can calculate a surface temperature of 750 Kelvin.

At the risk of demolishing an argument I find plausible, imagine Earth a couple of billion years ago, much too hot to allow water to condense on its surface. The atmospheric pressure would be ~300 bars so the atmosphere would be thicker than Venus’ with its puny 90 bars. Furthermore the atmosphere would be thicker in the ratio 48/14, given the molecular weights of the dominant gasses (CO2 and H2O respectively). Temperatures at the surface would be at least 1,000 Kelvin.

How is it that the Earth cooled but Venus did not?

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Meanwhile, from you, a 4 W/m2 now would have a ‘moderate effect’ and you’re suddenly happy to start talking about the concept of climate sensitivity — you sure changed your tune

Are you being deliberately obtuse Barry? I never implied, nor intended to imply, nor believe, nor have ever believed, that 4W/m2 has zero effect on climate. If you actually read my original comment: you’ll see that I only ever took issue with the claim that 4W/m2 saved the Earth from going Venusian.

I have not changed my tune at all. You, however, got caught in an elementary error and tried to fudge your way out of it.

And then you ignore (forgot?) feedbacks, and imply that Hansen says 4W/m2 would be it. Take another peek at the chart shown in this post, and add up the cumulative forcing as forcing continues to double with methane release, albedo changes and other feedbacks (including, at the very end, an evaporated ocean).

None of the feedbacks make any difference to my argument. Hansen’s argument (and yours) is that a difference of 4W/m2 in Total Solar Irradiation (TSI) stopped the runaway greenhouse effect when CO2 concentration was 4000ppm (an order of magnitude higher than we’re likely to see from human influence). That argument might have some plausibility if not for the fact that 4W/m2 is less than 0.3% of the total which itself varies by 6.5% within a year.

Yes, I understand that the 0.3% is effectively constant whereas the 6.5% is oscillating. However, it is in no way plausible that the Earth stood poised to descend into runaway greenhouse for much of its history, but for such a tiny difference in forcing.

CO2 has varied by orders of magnitude. The temperature has been far hotter and far colder than today. Solar irrradiance has been higher and lower. The Earth’s axis has moved around. The continents have been all over the place. In all that variation over billions of years you want to claim we dodged the runaway greenhouse bullet by a few watts per meter squared? No way. If it was that close it would have already happened.

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libertarian, fine, I’m happy for you to go on believing what you like, if that gives you some comfort.

I’ll leave you with a passing thought. Say you’re bouncing on a trampoline, and each spring takes you 2 metres up/down. There is a concrete roof at 2.1 m. Someone then extends the trampoline’s legs by 15 cm. The difference between that small constant upwards adjustment, and your large bouncing swings, is relatively tiny. But your head sure feels the difference.

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Hi Barry,

Ha ha ha! Great analogy! As in so many Denialist arguments, they try to ignore the overall measurable trends while focussing on moment by moment details. They can’t see the forest for the trees, the 1998 La Nina super-spike compared to the decades long upward trends, and the SUN GETTING BRIGHTER over millions of years compared to the annual perihelion and aphelion.

Even the wiki states..

“In modern times, Earth’s perihelion occurs around January 3, and the aphelion around July 4 (for other eras, see precession and Milankovitch cycles). The changing Earth-Sun distance results in an increase of about 6.9%[2] in solar energy reaching the Earth at perihelion relative to aphelion. Since the southern hemisphere is tilted toward the Sun at about the same time that the Earth reaches the closest approach to the Sun, the southern hemisphere receives slightly more energy from the Sun than does the northern over the course of a year. However, this effect is much less significant than the total energy change due to the axial tilt, and most of the excess energy is absorbed by the higher proportion of water in the southern hemisphere.[3]”

http://en.wikipedia.org/wiki/Earth%27s_orbit#Influence_on_the_earth

Denialists want their audience to get bamboozled by the details in their presentation, and then ask an outright dishonest question leading to their dishonest conclusions.

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Hi Barry,
another factor that is interesting is continental drift over those millions of years. I wonder if January was always the coolest (global) month back when Pangea ruled the world. Has the southern January tilt always exposed more water, cancelling out the swings in global temperature we might otherwise expect?

All this explains why July is our planet’s warmest month: Northern continents baked by the aphelion Sun elevate the average temperature of the entire globe. January, on the other hand, is the coolest month because that’s when our planet presents its water-dominated hemisphere to the Sun. “We’re closer to the Sun in January,” says Spencer, “but the extra sunlight gets spread throughout the oceans.” Southern summer in January (perihelion) is therefore cooler than northern summer in July (aphelion).

http://science.nasa.gov/science-news/science-at-nasa/2002/02jul_aphelion/

Anyway, don’t expect Libertarian to admit that the dominant oceanic surface of the south overcompensates for the increased TSI during January, because Libertarian just wants to emphasise the overall TSI perihelion / aphelion cycle’s 6% difference, without looking at where that 6% falls.

Dude, the globe is COOLER when the TSI is 6% HIGHER (closer to the sun). So Barry’s analogy, while amusing, doesn’t necessarily hold true, because the 6% TSI is cancelled out by other factors (as luck would have it or maybe our weather patterns would be more erratic!)

How interesting that you never mentioned the huge affect of the northern continents on warming the world when the TSI is at it’s weakest, or the southern oceans on cooling the world when the TSI is at it’s strongest? (Nudge nudge wink wink)

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I am no expert, but would the annual variation in solar radiation hitting the Earth be of any relevance if the effects of small changes in such radiation take many months, or years, to have an effect?

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Say you’re bouncing on a trampoline, and each spring takes you 2 metres up/down. There is a concrete roof at 2.1 m. Someone then extends the trampoline’s legs by 15 cm. The difference between that small constant upwards adjustment, and your large bouncing swings, is relatively tiny. But your head sure feels the difference.

Lets make your analogy fit the situation at hand, Barry.

You can’t see the concrete roof. You only surmise its existence and height based on some not very well understood science (and I mean that non-pejoratively – this is not the fine structure of the hydrogen spectrum).

You’ve been bouncing on that trampoline for billions of years. The mat has been tauter at times and slacker at other times. The springs have been tighter and looser. The air denser and sparser. All these effects have at one time or another changed your bounce height by considerably more than 15cm. You don’t know all the times those effects have reinforced and when they have cancelled, but you do know that you have never before hit the concrete roof.

Instead of concluding the roof is likely a lot higher than 2.1m, or perhaps doesn’t exist at all, you posit a theory that by some monumental fluke all those other effects have always cancelled each other sufficiently to keep your head below 2.1m It’s not plausible.

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mw, JB, liberatarian, whatever, on what basis are you apparently so confident that net global climate forcing has been higher in the past (near or deep time) than is projected for a scenario where all the available fossil fuels are burned? What particular lines of evidence, relating to this assumption, do you place most credence in? Or, to look at it another way, what probability would you place on this underpinning assumption? Unforced orbital eccentricity is obviously not relevant to this question, and so, returning to your original post and my first reply, I’m still confused as to why you brought this up?

Overall, your modified analogy is clever, and, as indicated in my original post (which I’d ask you read again) I agree that there is no certainty in such a hypothesis, and that palaeoclimate offers some reasonable reassurance. Above, I obliquely implied the odds may be no better than 1%. My conclusion, however, was that this was not sufficiently reassuring to continue BAU fossil fuel combustion, when a better alternative is already in the offing.

some not very well understood science (and I mean that non-pejoratively

If no pejorative was intended, why use terms like “BS” and “climate science has zero credibility”?

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Anyway, don’t expect Libertarian to admit that the dominant oceanic surface of the south overcompensates for the increased TSI during January, because Libertarian just wants to emphasise the overall TSI perihelion / aphelion cycle’s 6% difference, without looking at where that 6% falls.

Actually eclipsenow, your example makes my point. Read my original comment, I acknowledged the seasonal forcing change has almost no measurable effect:

Or to put it another way, do you really believe the Earth’s thermodynamics are on such a hair-trigger than a 4W/m² increase in irradiance out of 1400 4W/m² would cause runaway greenhouse, yet the 91W/m² change from July to January has almost no measurable effect?

You don’t need to move the oceans much to negate the cancellation, yet it still wouldn’t trigger runaway greenhouse. And the oceans have been in very different configurations than they are today. As have many other variables that determine climate. Yet in all those myriad different configurations of the planet and sun over billions of years, configurations that have moved a lot more than 4W/m2 around, we’ve never had runaway greenhouse.

But apparently Hansen knows that if not for a 4W/m2 solar deficit when CO2 was 4,000ppm, none of us would be here today to debate this? Gimme a break. That is just bad science.

You can bet that if a prominent skeptic ran such an argument supporting their position they’d be eviscerated by the climate priesthood.

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In my last post I was trying to get things back on the subject of Venus. As everyone else wants to discuss radiative forcing I will go along with it. After all, radiative forcing is at the heart of the climate debate.

Earlier I made the point that Roy Spencer and Richard Lindzen using satellite measurements (CERES & Aqua) have concluded that Earth’s sensitivity to radiative forcing is low owing to NEGATIVE feedback (f = -0.3), in sharp contrast with the IPCC’s models that all have POSITIVE feedback coefficients. http://www.drroyspencer.com/2010/04/update-cloud-forcing-paper-finally-accepted-to-jgr/

eclipsenow said:
“Dude, the globe is COOLER when the TSI is 6% HIGHER (closer to the sun). So Barry’s analogy, while amusing, doesn’t necessarily hold true, because the 6% TSI is cancelled out by other factors (as luck would have it or maybe our weather patterns would be more erratic!)”

eclipsenow’s statement implies that the feedback is negative and fast acting. It is easy to understand why this is probably correct; increased TSI causes greater evaporation in the low latitudes thereby increasing cloud cover.

In my opinion “eclipsenow” is right to conclude that the TSI annual oscillation with an amplitude of 91 W/sq. meter has very little effect owing to negative feedbacks.

However, the same feedback mechanisms also apply to longer term effects such as the putative 4 W/sq. meter forcing due to CO2, so I am with “libertarian” when people start talking “Catastrophe” in relation to an effect that is proving very difficult to measure.

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Libertarian,

1. you’re coming on a bit hard about one speculative post by Barry’s. Correct me if I’m wrong Barry, but you’re not nailing your colours to this particular Venusian mast are you? You’ve said it is possible, but not probable or inevitable. And then to top it all off, you go an get on your high horse as if this is how ALL climatologists think, and it shows how silly climate science is etc etc yadda yadda.

2. You make this huge fuss about the annual variation being 22 times the 4W/m2, yet totally ignore:
a/ the moment it gets to it’s highest TSI, it starts to swing on the 6 month journey towards the lowest TSI. Yet you ignore that it takes time for a climate forcing to take place. So the net effect in a year is actually zero, because you are always back where you started. Climate is measured in decades, centuries, and millennia. So what the heck is your point? You don’t have one.

b/ You also ignore that most of the 6% change in TSI is negated by other climate factors (continents and oceans). In other words, the TSI maximums don’t get translated into HEAT which is what we’re really interested in in this discussion. Net effect again? Pretty close to zero.

c/ But the sun has increased it’s TSI by 4W/m2, and this is consistent over decades, centuries, millennia, and even millions of years. This is REALLY long term stuff.

d/ You keep trotting out 4000 parts per million CO2!!!! The earth survived FOUR-THOUSAND-PARTS-PER-MILLION! (I have in mind Austin Powers asking for 1 MILLION DOLLARS!)

In reality, the extra greenhouse returns after a certain point diminish. (Where is that Barry… around 1000ppm?) Up to this point, most of the damage has been done, but beyond that… well, diminishing returns on the damage. So the point is the earth survived slipping into runaway greenhouse gases with just 4W/m2 at those incredibly high Co2 levels because, well, they’re not *really* that incredibly high after a certain point. The real climate damage is done at a much lower level, and we are closer to that point of no return than you’ll ever admit.

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OOooppsss… Barry, I switched back to talking to Libertarian at this point. Sorry if I caused offence.

And then to top it all off, you go an get on your high horse as if this is how ALL climatologists think, and it shows how silly climate science is etc etc yadda yadda.

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Living in denial: Why sensible people reject the truth

Kalichman, feels that everyday reasoning alone is not enough to make someone a denialist. “There is some fragility in their thinking that draws them to believe people who are easily exposed as frauds,” he says. “Most of us don’t believe what they say, even if we want to. Understanding why some do may help us find solutions.”

He believes the instigators of denialist movements have more serious psychological problems than most of their followers. “They display all the features of paranoid personality disorder”, he says, including anger, intolerance of criticism, and what psychiatrists call a grandiose sense of their own importance. “Ultimately, their denialism is a mental health problem. That is why these movements all have the same features, especially the underlying conspiracy theory.”

Source:http://www.newscientist.com/article/mg20627606.100-living-in-denial-why-sensible-people-reject-the-truth.html?full=true

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From the article: bullet points on how to be a denialist.

1. Allege that there’s a conspiracy. Claim that scientific consensus has arisen through collusion rather than the accumulation of evidence.
2. Use fake experts to support your story. “Denial always starts with a cadre of pseudo-experts with some credentials that create a facade of credibility,” says Seth Kalichman of the University of Connecticut.
3. Cherry-pick the evidence: trumpet whatever appears to support your case and ignore or rubbish the rest. Carry on trotting out supportive evidence even after it has been discredited.
4. Create impossible standards for your opponents. Claim that the existing evidence is not good enough and demand more. If your opponent comes up with evidence you have demanded, move the goalposts.
5. Use logical fallacies. Hitler opposed smoking, so anti-smoking measures are Nazi. Deliberately misrepresent the scientific consensus and then knock down your straw man.
6. Manufacture doubt. Falsely portray scientists as so divided that basing policy on their advice would be premature. Insist “both sides” must be heard and cry censorship when “dissenting” arguments or experts are rejected.

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on what basis are you apparently so confident that net global climate forcing has been higher in the past (near or deep time) than is projected for a scenario where all the available fossil fuels are burned?

I am not claiming that. All I am claiming is Hansen’s argument that 4,000ppm of CO2 didn’t cause runaway greenhouse due to 4W/m2 less solar forcing is bogus.

However, who says all available fossil fuels will be burnt? We don’t even know how much coal is out there. You are likely talking hundreds of years at a time of exponential technological development. We’ll be well off fossil fuels before they are even close to exhausted.

Unforced orbital eccentricity is obviously not relevant to this question, and so, returning to your original post and my first reply, I’m still confused as to why you brought this up?

To demonstrate the absurdity of claiming 4W/m2 is all that has separated us from runaway greenhouse disaster. When annual variability is 20 times greater, and the actual forcing is 350 times greater, something stinks.

I obliquely implied the odds may be no better than 1%.

Why not 3%? 0.1%? 0.0006%? No doubt you picked 1% because 10% is clearly too large, and we have 10 fingers so work naturally in base 10 hence lopping off a digit (no pun intended) gives you 1%. A psychologically and anatomically comforting number to be sure, but with zero scientific justification. Just because you can imagine a scenario does not mean you can assign a valid objective probability to it.

If no pejorative was intended, why use terms like “BS” and “climate science has zero credibility”?

I intended no pejorative concerning our poor understanding of climate science because it is a complex and multi-faceted discipline. However, I have nothing but contempt for those who exploit our uncertainty for political ends. Unfortunately, in addition to the usual culprits – activists, zealots, and politicians – that group also includes a large fraction of the climate science community itself.

Anyway, I have said my piece. If anyone wishes to read more analysis of the state of climate science from someone far more qualified to opine on such matters, I suggest checking out Richard Lindzen’s latest talk

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Hey, DV8, I love the way that New Scientist article opens!

HEARD the latest? The swine flu pandemic was a hoax: scientists, governments and the World Health Organization cooked it up in a vast conspiracy so that vaccine companies could make money.

I always advise Denialists to carry around plenty of Vaseline (lubricant sold here in Australia) because “You never know man, when the ALIENS are going to probe you maaaaan, because like they KNOW they’re out there man, they’ve got some at Area 51 and like it’s a conspiracy of the guv-ern-ment maaaaaaan!”

So please, lub up boys, because you just can’t imagine how deep the conspiracy goes…

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Libertarian says:

To demonstrate the absurdity of claiming 4W/m2 is all that has separated us from runaway greenhouse disaster. When annual variability is 20 times greater, and the actual forcing is 350 times greater, something stinks.

Except that it’s not 20 times greater, or 350 times greater. See my post here which you completely ignored.

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I was interested in the discussions on Venus and radiative forcing but now we are into the alleged motivation of “Deniers” it is time to find another thread.

The “New Scientist” has been in decline for many years but I never thought it would descend to the level of the “National Enquirer”.

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if earth’s sensitivity to climate feedback is so low, ala Lindzen, how do you explain the palaeoclimate record, which is what Hansen and others rely on in their climate sensitivity estimates?

as barry commonsensically asked, how did climate ever change naturally in the past, other than via the predictable long-term shifts in eccentricity on a ~50 kyr semi-amplitude? (by negative feedback mechanisms that balance out initial forcing? this answer makes no sense to me)

We have to explain rapid temperature shifts in the climate record? how does Lindzen explain these rapid shifts?

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He can’t greg. It’s a fundamental problem for those who offer a predominance of -ve feedbacks. Palaeoclimates tell us, very clearly, that amplifying feedbacks predominate, although, if the +ve forcing operates on a sufficiently slow scale, -ve feedbacks will eventually compensate. One of Hansen’s key justifications for the ‘Venus syndrome’ is the rate of the current forcing, and that projected should we burn all the coal, oil and gas and start moving into exploitation of tar sands, oil shales and seafloor methane.

gallopingcamel, please read a little deeper, and if you’re going to critique Hansen, please read his work first. He makes a very strong scientific case for a predominant role of CO2 as a forcing (and feedback) in deep time.

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greg meyerson,
What caused those past climate shifts on long time scales? As you point out, the best explanations we have today rely on Milankovitch cycles but there are still plenty of unanswered questions.

Shaviv, Svensmark and several others have suggested that cosmic rays play a major role in determining climate both long term as the Earth moves through the spiral arms of the galaxy and short term owing to solar wind. Lindzen has expressed skepticism about these ideas but if he has a better idea, I have yet to hear of it.

In my opinion we simply don’t know know enough yet and it is not helpful for folks like Hansen to pretend otherwise. One hypothesis that fails dismally on long time scales is Hansen’s idea that CO2 concentrations are the main driver of climate change.

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Barry,
Hansen made his name modelling the climate on Venus. I used to think he was on to something but now I can see that the adiabatic lapse rate in a thick atmosphere contributes more than the greenhouse effect on Venus and on Earth too.

Anyone who thinks that the mega-year climate record supports the concept that CO2 had a “predominant” role in shaping Earth’s climate needs to abandon the quaint idea that cause precedes effect. I am not ready to do that yet, even if James Hansen demands it.

Fortunately, Hansen’s ideas on CO2 are capable of being tested in the short term. If he is right, the Earth will start warming to the point that the temperature increase will be more than a few tenths of a degree Kelvin so that measurements will indeed be “unequivocal”.

In another 20 years the effect of CO2 on climate will be resolved beyond all doubt given that the People’s Republic of China will continue to open a new coal fired power plant every few weeks while building as many cars as they can.

Please note that I hold this blog and its thoughtful commenters in the highest esteem and do not want to become “persona non grata” by pushing my anti-CAGW views.

My main interest is energy policy, rather than “Climate Science”.

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Please note that I hold this blog and its thoughtful commenters in the highest esteem and do not want to become “persona non grata” by pushing my anti-CAGW views.

There is no risk of that, gallopingcamel. Sensible sceptical questions, arguements are always welcome here, and I found your comments to be just that. Even ‘libertarian’ made some good points, but that was offset by the offence I took at his baseless sprays about people’s — or whole scientific field’s — motivations and credibility.

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I have a number of problems with the physics.

1. Working on the SURFACE energy balance, if the temperature increased 3DegC, it would require an increase in forcing of between 22 and 32W/m^2 to maintain the new temperature (lower figure is for an increase in evaporation of 7.5%, higher is for 20%). It is not clear that the increase of 3.7W/m^2 in forcing at the Tropopause will translate to 22-32W/m^2 at the Surface.

2. The absorption of 15um photons by CO2 is extremely fierce. For wavenumber 650 (not the most active part of the spectrum, which is 670, but I don’t have absorption figures for 670), over 50% of photons emitted from the surface have been absorbed in the first 25m of atmosphere. At the top of the atmosphere, absorption is still occurring, and the absorption tables strongly suggest that the emissions from CO2 which make it to space are coming from the lower Stratosphere and above, NOT from below the Tropopause. Confirmation of this is shown in the satellite spectra (see http://www.sundogpublishing.com/AtmosRad/Excerpts/AtmosRad217.pdf), where the emissions at wavenumber 670 are more intense than for wavenumber 650. Because these are necessarily being emitted from higher, it is clear that the temperature gradient is positive and therefore ABOVE the tropopause. The implication is that increased CO2 results in a decrease in forcing.

3. Even allowing that a doubling of CO2 results in a 3.7W/m^2 increase in “Radiative Forcing” at the bottom of the Tropopause, it is not clear how that translates down to the Surface. One can believe in a fixed Lapse Rate, and also in magic – there is no reason why the thin upper air cannot locally heat or cool, and radiosonde data confirms what a variable feast the Tropopause really is. Take a dekko at http://weather.uwyo.edu/upperair/sounding.html

4. In summary my 3 problems are:
a. The Surface is much more insensitive to changes in forcing than the Tropopause.
b. Absorption tables for CO2 suggest that emissions to space come from above the Tropopause, and
c. A warming of the atmosphere at the Tropopause does not magically translate to the same warming at the surface: there has to be a 5-8 fold amplification of “forcing”(depending on one’s guess at evaporation) and it is not clear that this occurs.

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Fred,
Most of the issues you raise are made complex by the highly variable concentration of water vapor in the lower atmosphere. For example, it is well established by copious measurements that Earth’s adiabatic lapse rate varies between 5 and 10 Kelvin/km depending on water vapor content.

Although much fewer measurements have been made on Venus, the measured lapse rate is in the range 7 to 10 Kelvin/km, compared to the calculated (dry) lapse rate of 10.5 Kelvin/km. The vapor that is causing the reduction in lapse appears to be sulphuric acid.

Likewise with absorption spectra. How much of the greenhouse effect is caused by CO2 and how much by water vapor? While CO2 is highly absorbent around 14.9 microns (wave number 670), water vapor can be dominant at other wavelengths owing to its relative abundance.

The answers to many of your questions will become clearer as the debate over feedbacks unfolds. The furor over the Earth Radiation Balance Experiment and Lindzen & Choi, 2009 is still going on. Fresh fuel to this fire can be expected when Roy Spencer’s much anticipated paper appears in JGR.

My opinion is that the the feedbacks are more likely to be negative/damping (Lindzen & Co.) than positive/amplifying (IPCC). One of my reasons for believing this is that we hardly notice the 90 W/sq. meter annual oscillation in Total Solar Irradiance as discussed earlier in this thread.

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Barry,
A couple of AGW scientists showed up at the recent ICCC conference in Chicago. Here is a presentation made by one of them:

http://www.heartland.org/events/2010Chicago/PowerPoints/Scott_Denning.ppt

In my opinion a pretty nifty explanation of radiative forcing for non-experts. Note that Denning arrives at a 1.2 Kelvin/CO2 doubling which leading skeptics such as Lindzen have no quarrel with.

Climate science needs some bridge builders so let’s hope there are more Scott Dennings out there.

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From Hansen, for whatever it’s worth:

Changes in solar irradiance for the 10,000 year period between the last glacial period and the holocene were about .0002 watts. Climate forcing due to ghg changes was 3 watts and the albedo effect was 3.5 watts.

The total forcing “maintained an equilibrium temp change of 5 degrees celsius,” “implying a climate sensitivity of about .75 degree C” per watt of forcing. This climate sensitivity holds for a range of climate states and converts to a 3 degree C climate sensitivity “for a 4 watt forcing of doubled carbon dioxide.”

SOLAR IRRADIANCE had little to do with it (the 5 degree temp change, though the orbital changes associated with the SI were an instigator). Hansen treats the climate sensitivity issue in the palaeoclimate record as solved.

Lindzen’s mechanism of negative feedback thus isn’t reflected in the climate record. H argues that L’s views derive from a “theological or philosophical perspective that he doggedly adheres to.” (55)

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I agree with GallopingCamel that in the real world the lapse rate is highly variable.
Let us assume that the atmosphere gets optically thicker at 15um, and that this means that the radiation of 15um photons to space comes from higher up, and that this is from a colder layer (an assumption which I think is shaky).
There is no change in surface conditions. The same temperature, evaporation and energy balance apply. So the same rate of energy is being pumped into the atmosphere by the surface, but up high there is a shortfall in the energy being sent to space.
So what would happen is that where the system is imbalanced (ie at the 15um radiating level) the air would warm up.
Full Stop. There is no need (or ability) to alter the surface conditions. The energy is being delivered to near the right place high in the atmosphere. It can’t get out, so that place warms up until the energy can get out.
(And that’s what I see in the Radiosonde data – the Tropopause is highly variable, it is not an area of exactly constant temperature.)

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These shows are great for the kids. They’re not too technical, are very visual, and talk about places of interest for the tourist. (This approach makes it more accessible).

Thanks for reminding me, my PVR is pre-programmed to record it but it is good to remember there’s something cool on.

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Does a significant difference between Venus and Earth reside in the different rotations and geomagnetic fields characteristic of the two? Venus barely rotates and possesses a minimal magnetic field. Earth is quite different. Venus’ lack of a magnetic field denied its primordial atmosphere, rich in H2O, any protection from ionising particle radiation. The dissociation of water molecules occured, and combined with the high energy solar charged flux at lower atmospheric levels, resulted in the massive leaching of hydrogen from the Venusian atmosphere. That process is negligible on Earth.

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[…] Climate change, left unabated, will increase the frequency and severity of natural disasters. More and more energy is being trapped within the Earth system (see figure to the right), and it has to be expressed somewhere, sometime. The laws of physical science dictate nothing less. And it will, in turn, hit the Australian and World economy hard. Those economic rationalists among us should heed the reminder that these latest natural events have delivered. Avoided global heating is avoided cost (with the worst-case scenarios being incalculable). […]

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Just for the history books, check out this comment above in the light of hindsight.

////DV82XL, on 10 May 2010 at 11:55 AM said:

eclipsenow, – First, and by God I’m going to set this to music: NO NUCLEAR POWER REACTOR OF THE SORT IN USE IN THE WEST CAN FAIL LIKE CHERNOBYL – IT JUST CANNOT HAPPEN DUE TO THE TYPE OF DESIGN AND THE LEVEL OF CONTAINMENT MANDATED BY LAW.

There will never be another Chernobyl, or anything close.////
I wonder how that music is playing now?

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EN, you need to keep the context. Fukushima was nothing like Chernnobyl – the accident was totally different. The total radiological release was 4.5% of Chernobyl, and the reactor core did not massively overpower and blow up – this was not possible for these LWRs, as DV82XL stated.

Still, it was a lot worse than I or DV8 would have imagined possible, even for this old design hit with a massive extreme event, I’ll certainly grant that, and lessons in over-confidence should be hard won.

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Hi Barry,
And I was also impressed that even anti-nuclear activist Ian Lowe says Chernobyl was ‘sabotaged’.

Personally I would want to site all nukes far away from large cities. I’m not a fan of the small-nuke idea integrated into every few suburbs! If we’re *forced* to use this technology then for pity’s sake play it safe.

My preference would be for BIG nukes placed hundreds of km’s away from our major cities. The cost of some extra HVDC wiring is NOTHING on having to evacuate a major modern city! Build them in places that could easily be turned into ‘natural parks’ for a few hundred years should some unforeseen accident blow the thing. However unlikely, we need to be prepared.

So I still support nuclear power… but *well* outside our major cities. Australia has lots of deserts. Would they work? Air cooled towers?

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As DV82XL does not post here any more I need to point out that his statement that “Chernobyl cannot happen…..” was not disproved by Fukushima.

That said, I agree with Barry’s comment that Fukushima was a lot worse than any of us could have imagined……………yet nobody died. Compare that with an airline accident or Bhopal.

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I’m not a fan of the small-nuke idea integrated into every few suburbs! If we’re *forced* to use this technology then for pity’s sake play it safe.

“Forced”? Why the prejudicial choice of words? I thought we were doing it because it’s the nicest option. There are others. If all our major coastal communities come to need tall dikes, the Dutch have shown us this can be done. It’s an option.

Small nukes now are integrated into small floating suburbs. The one Lonnie Dupre is photographed posing with has two.

Notice the name on the masthead. Another time, he and another man were rescued off an ice floe by this same boat, and this got into the papers, and their routine use of it became known. So eventually the sponsoring outfit had a choice of showing moral courage, or going to one of those other options. They now operate the MV Arctic Sunrise. Despite the “sun” in its name, it is diesel-powered.

Perhaps someday they’ll ride in it along one of those dikes, and look down on us.

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Remote location of nuclear facilities seems to me to be a concession to the FUD about nuclear energy. It may be a necessary compromise to accommodate fear, which is so much more emotionally compelling than logic and facts, but it remains a foolish waste of resources nonetheless.

Put an SMR in the basement of our commercial building here in the the upper Midwest of the U.S. (it would be the second reactor in town, we have one at the University) and we could district heat the downtown, grow our own winter vegetables with the excess heat, electrify the city and eliminate the local coal-biomass choker, thus cleaning up the air around here and probably extending lives that would otherwise be shortened by air pollution.

Its a more efficient use of resources, by far.

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Frank Jablonski,

I agree. There are so many small nuclear reactors out there already. For example there are over 400 powering ships.

If the government would encourage GE to build PRISM reactors rather than windmills it would not take long to create a robust electricity generating infra-structure with much less reliance on high voltage transmisssion systems and vast power plants.

I am a little puzzled that nobody has developed an MSR to power ships given the small size (owing to higher operating temperatures) and the possibility of simpler, more reliable safety systems.

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Frank, you’re missing the irony of what happened up-thread. I spoke about how impossible it would be to promote nuclear power if there was *another* Chernobyl and was told it was physically impossible. Then Fukishima happened, which saw 1/20th the radiation released, but still also saw an enormous area of highly valuable land evacuated. I love Sydney. I don’t want it evacuated. FUD? How can you say that when:
* None of us can see the future
* I nervously asked “What if” and was told it couldn’t happen — and then it DID!

Now I’ve raved (in my layman’s terms) about the benefits of “neutron leak” passive safety physics in reactor fuel rods themselves, as a last ditch safety system to fall back on even IF the brand-spanking shiny new cooling systems fail, which is pretty unimaginable. But I’ve also raved about the need for safety, and against Peter Lang’s “Cheaper nukes at any cost” economic rationalism. I’ve done my time defending nuclear power as best I can (with a poor layman’s understanding of the technology and not a lot of time to study serious books on the topic). But here’s the thing. Barry’s published books on nuclear power that recommend distant energy parks outside our cities, and I agree with that both because it makes sense, and because given the nervous state of Australian culture towards nuclear power, I think we need it as an activist strategy as well.

So don’t you DARE accuse me of FUD given the history I’ve had of being patronised on this thread and patted on the head and assured everything would be OK, and then it really, really wasn’t.

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EN – l’d say you are being disingenuous and that you are guilty of FUD as espoused.
Fukushima wasn’t another Chernobyl!
Chernobyl had no containment dome; Fukushima did.
Hydrogen explosions occured at Fukushima and blew the outer building shell but there was no explosion of nuclear material. Thankfully, unlike the 28 workers at Chernobyl, no-one was killed at Fukushima and, according to the latest UN/WHO report on Fukushima radiation, the likelihood of getting cancer has increased by only 0.003%, not measureable above usual levels of the disease.

Click to access 9789241503662_eng.pdf

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I think EN has a point, though I don’t agree entirely.

While the radiological release was much less from Fukushima, the overall results are pretty much the same as Chernobyl. Little to no long-term physical health implications, a vast area vacated, and (assumedly) long-lasting psychological impacts. An out-of-control media reaction (excuse the pun). The event was different, but the consequences essentially the same.

If we replaced the 1.3 GW Torrens Island gas plant here in Adelaide with a large nuke (for example), and something remotely like Fukushima happened, current policy would likely see a large area evacuated – regardless of how little that makes sense. That would not appease peoples’ fears.

Perhaps it’s a concession we have to make? But then again, Frank Jablonski’s point about playing into the hands of the fear-mongerers by placing them remotely wouldn’t help either.

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Ms Perps,
“Fukushima wasn’t another Chernobyl!” and then you quote a bunch of irrelevant technobabble. Do you *honestly* think any of your technobabble has *any* comfort value to the average Aussie? It’s just words. The *facts* are that it released 1/ 20th of the radiation of Chernobyl, which was serious enough to vacate a VAST area of Japan. This is the *MAIN* effect I am talking about and you haven’t even bothered to mention. The economic implications of this are CATASTROPHIC if applied to Sydney.

///EN – l’d say you are being disingenuous and that you are guilty of FUD as espoused.///
When I stop my online activism FOR nuclear power, and tell you I’ve dropped my support for nuclear power based on these concerns, THEN you can accuse me of FUD! But as I’m just voicing my support for Barry Brook’s concept of energy parks well outside city limits, then I guess your accusations of FUD apply to Barry Brook as well.

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It is strange to find myself on the same side as “ms.perps” but she sees the big picture more clearly than “Eclipse Now”.

Many of the things we do are inherently dangerous. We drive cars, fly aeroplanes, dig up minerals, grow food, build houses, dam rivers, manufacture chemicals and so on. The death toll associated with these activities is immense but we have learned to take the dangers in our stride because the benefits outweigh the risks.

With nuclear power the FUD factor causes us to exaggerate the risk so we evacuate huge areas whenever there are significant releases of fission products.

The use of nuclear power is a choice made by nations rather than individuals or corporations. Consequently some nations will shun nuclear power and others will embrace it with enthusiasm. As times roll by the nuclear “Club” will out perform the others economically. To borrow from Mark Twain “…that will gratify some and amaze the rest.”

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Ms Perps,
“Fukushima wasn’t another Chernobyl!” and then you quote a bunch of irrelevant technobabble. Do you *honestly* think any of your technobabble has *any* comfort value to the average Aussie? It’s just words. The *facts* are that it released 1/ 20th of the radiation of Chernobyl, which was serious enough to vacate a VAST area of Japan

Vast, but inhabited by a very small fraction of Japan’s population.

I would say the released radioactive material, along with the Japanese government’s financial interest in natural gas, along with the smallness of the above-mentioned fraction, were together enough to give those people the boot.

If it had been a part of Tokyo inhabited by senior mandarins (can you call civil servants mandarins if they are Japanese?), and staging a good radiophobia drama would have required them to relocate themselves and their families, they would not have done so. No-one’s going to go to that much trouble just to fatten the public purse a little, and avoid years of radiation exposure that — if received instantly — would be as bad as a few CT scans.

Only if they could limit the heavy thespian lifting to a few unimportant hicks could the show go on.

Finally, the *facts* are not as simple, nor as stark, as you say. More later.

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Just to get the evacuation limit into perspective, it amounts to a third of 1% of Japan’s land mass.
Barry provided an infographic demonstrating the coverage of solar thermal power stations needed to replace the output from just the Daiichi nuclear plan, would encompass the whole of the 20 mile exclusion zone.
https://bravenewclimate.com/tcase7
Imagine how much land would be needed to replace the output of Japan’s nuclear fleet! No nuclear power=more fossil fuel power=more warming.
Emissions in Japan (and Germany) have risen dramatically during the last 12 months.

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///it amounts to a third of 1% of Japan’s land mass.///
Oh come ON Ms Perps! I feel like I’m in some kind of bizarro-world conversation where you’ve suddenly turned into Peter Lang! This is a FINE example of lies, damn lies and statistics! Do you really think the *actual* percentage area is important? When I say it’s a VAST area, I’m talking about relative to something in particular, aren’t I Ms Perps? Can you go back and re-read my posts and see if you can identify exactly what I’m worried about?

Put it this way, do I care if 0.001% of Australia gets covered in a fine coating of radioactive dust if it’s out in the desert twice as far as whoop-te-do? No! That’s the point isn’t it? That’s why I’m actually here trying to REDUCE Australian FUD by backing Barry’s recommendation for remote energy parks. Because I DO care if a 20km radius of Sydney is evacuated!

I remain a passionate advocate for nuclear power IF positioned correctly, and that means away from things like tsunami prone coastlines and capital cities.
MODERATOR
Snide, patronising remarks removed.

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Lies, damn lies and statistics, eh? Reminiscent of the anti-nuke lobby’s radiation scare tactics.
You said VAST – vast to me means what the dictionary states:
1.
of very great area or extent; immense: the vast reaches of outer space.
2.
of very great size or proportions; huge; enormous
3.
very great in number, quantity, amount,
4.
very great in degree, intensity, etc.

Choose your hyperbole more carefully:)

There are places in the world where there is no way a nuclear power plant could be situated in remote regions away from large populations e.g. UK, and most of the rest of Europe.
Your argument is, therefore, a deterrent to the take up of nuclear power in such places.
The point is that new generation nuclear plants don’t need to be sited remotely. They have passive safety systems governed by physics. They are as safe (actually safer) than having a large hydro dam burst over an area or a huge oil refinery fire engulf a community.
The risk to land, health and humanity is far greater if we delay the build out of nuclear power worldwide, thus allowing fossil fuels to continue to destabilise the world’s weather systems and locking in up to 6 degrees of warming. You will really have to worry about VAST areas of uninhabitable land then, and disease, death and dislocation on a mammoth scale.
Promulgating FUD around nuclear power will stymie any hope of avoiding such a catastrophic situation.
I normally agree with most of what you say EN – but in this case we will have to differ.

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The last I looked, the UK, and most of the rest of Europe already *have* nukes. My ‘argument’ is a simple statement that here in Australia where nukes are not yet even on the agenda, we can *afford* to promise to stick them out in whoop-whoop if that helps us get our first commercial nuclear power plant built. OK? Nothing more. Nothing less. Just that *extra* level of safety that won’t cost us too much, really. Especially compared to the unaffordable renewables.

The point is I *know* about passive safety systems and all that jazz, but I also *know* from personal experience that most advocates on this site were swearing black and blue that Fukishima was going to be nothing: a media beat up and exaggeration. And yet that exclusion zone remains a 30km radius from Fukishima, and will cost a trillion yen to clean up. It was far, far worse than people here predicted, as can be seen up-thread a little. I mentioned having a strategy in case accidents happened, and was almost nagged off the board for being such a FUDdy duddy wowser. Well guess what? I was, sadly, right, and a “Black Swan” event did strike.

And it was pretty bad.

http://en.wikipedia.org/wiki/Japanese_reaction_to_Fukushima_Daiichi_nuclear_disaster#Evacuationsc

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