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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.
Filed under: Future
I agree that even the remote possibility of a Venus-type runaway warming scenario should significantly affect our risk analysis.
After all, moving away from fossil fuels will eventually be necessary, regardless of what we do. They are fundamentally exhaustible resources. What we are considering now is an accelerated phaseout. In return, we reduce risks that range from certainties (ocean acidification, etc) to ones that are unlikely but terrifying (Venus).
We would also rid ourselves of the many non-climate costs of fossil fuels: from air pollution deaths to geopolitical vulnerability.
Although you (Barry Brook) are on the wrong side in the AGW debate I enjoy reading your posts, especially when they concern energy policy. Very few academics have your grasp of the “big picture” relating to long term energy issues.
It was therefore quite a shock to find you taking Hansen’s fairy stories seriously. Then I got to the bit where you recognized that the boiling ocean scenario is not plausible and that that stopped me hyper-ventilating!
Venus and Mars where on of the greater disappointments in my life. Having grown up on a diet of science fiction that assumed Venus was a jungle rainforest planet, and Mars a desert, with the scattered runes of an ancient alien civilisation, I was saddened to learn the truth.
Perhaps one day we will terraform these worlds into new homes. It would certainly be a noble project, worthy of a mature humanity.
Steve Goddard has suggested that the adiabatic lapse rate is the major factor contributing to the high surface temperatures on Venus.
See WUWT:
http://wattsupwiththat.com/2010/05/06/hyperventilating-on-venus/
Lubos Motl has been known to savage sloppy science from both sides of the AGW debate so I was pleased to find that he has done a quick sanity check on Steve’s numbers:
http://motls.blogspot.com/2010/05/hyperventilating-on-venus.html
I imagine that if one could climb a mountain on Venus the temperature would fall just like it does here on Earth. This temperature gradient is not dependent on the “Greenhouse” effect.
I doubt the runaway grenhouse effect is a possibility for earth yet. Kicking the earth into a ‘moist greenhouse’ state (temperatures rise enough to undo the cold trap at the tropopause and water vapour saturates the whole atmosphere and keeps building up until we have a 10-15 bar steam atmosphere where hydrogen loss to space is balanced by replenishment from the ocean) would require a 10% increase in insolation (predicted for ~1 billion years or so in the future). Well before that could occur as a result of CO2 increases, the greater hydrological activity should have purged the excess CO2 from the atmosphere. Our existential problem is what happens in that interval of ‘greater hydrological activity’, which should be worrisome enough.
I imagine that if one could climb a mountain on Venus the temperature would fall just like it does here on Earth. This temperature gradient is not dependent on the “Greenhouse” effect.
Denying the existence of the greenhouse effect (confirmed for just about every planetary body with an atmosphere in the solar system) is the equivalent of introducing arguments from creationism to a paleontology debate.
And now to register to follow the thread….
Que the popcorn.
Sorry, nothing constructive. just don’t wanna miss this. how about adding a subscribe button hey?
The following comes from the first link provided by gallopingcamel:
I bought off on the “runaway greenhouse” idea on Venus for several decades (without smoking pot) and only very recently have come to understand that the theory is beyond absurd. I explain below.
The first problem is that the surface of Venus receives no direct sunshine. The Venusian atmosphere is full of dense, high clouds “30–40 km thick with bases at 30–35 km altitude.“ The way a greenhouse effect works is by shortwave radiation warming the ground, and greenhouse gases impeding the return of long wave radiation to space. Since there is very little sunshine reaching below 30km on Venus, it does not warm the surface much.
It doesn’t have to. Venus’ greenhouse increment is so enormous that the small amount of sunlight which does reach the surface (about the same as a heavily overcast day on earth) is sufficient to maintain the current temperature.
This is further evidenced by the fact that there is almost no difference in temperature on Venus between day and night. It is just as hot during their very long (1400 hours) nights, so the 485C temperatures can not be due to solar heating and a resultant greenhouse effect. The days on Venus are dim and the nights are pitch black.
The atmosphere is so thick it rapidly smooths out any surface temperature fluctuations. Venus’ atmosphere effectively migrated around the surface once every four days.
The next problem is that the albedo of Venus is very high, due to the 100% cloud cover. At least 65% of the sunshine received by Venus is immediately reflected back into space. Even the upper atmosphere doesn’t receive a lot of sunshine. The top of Venus’ atmosphere receives 1.9 times as much solar radiation as earth, but the albedo is more than double earth’s – so the net effect is that Venus’ upper atmosphere receives a lower TSI than earth.
This is irrelevant. There is enough sunlight getting through to drive the process. This part is just a restatement of the assertion that there’s not enough sunlight getting through. It’s nonsense.
The third problem is that Venus has almost no water vapor in the atmosphere. The concentration of water vapor is about one thousand times greater on earth.
The overwhelming mass of CO2 more than makes up for a lack of water vapour. By the way, if Venus had a steam atmosphere (which it likely did in the remote past), the temperature there would be much higher, possibly around 1200 C.
From gallopingcamel’s second link, we find a reader response which provides an excellent reductio ad absurdum argument:
reader The Blob said…
Even if Venus absorbed all sunlight it couldn’t be more than 55C. The only way it can be warmer than that is through it’s atmosphere absorbing infrared.
That means the hundreds of degrees warmer that Venus is, is due to the greenhouse effect.
If you turned off infrared absorption in Venus’s atmosphere, the planet would rapidly cool. The mere presence of high pressure isn’t going to keep it warm. The easiest way to see why is to note that if atmospheric pressure could keep Venus warm, it would imply a body like Venus could just sit in space generating heat forever, like some inexhaustible mini-star.
So Steve’s post is not just slightly wrong, the conclusion is completely wrong. The heat on Venus is caused by the greenhouse effect.
Finrod,
I don’t know where you got the idea that I was “denying the greenhouse effect”. As a physicist I have no problem with radiative forcing. It is just a question of getting the numbers right.
The “greenhouse effect” is clearly insufficient to explain the high surface temperature on Venus.
The observed adiabatic lapse rate on Earth is variable in the range 6-10 degrees K/km depending on the water vapor content of the local atmosphere. As there is much less water vapor on Venus, the dry adiabatic lapse rate would apply (10.5 degrees K/km).
You said “So Steve’s post is not just slightly wrong, the conclusion is completely wrong. The heat on Venus is caused by the greenhouse effect.”
Actually the heat is coming from the sun and the “greenhouse effect” is helping to retain some of it. Without layering in the atmosphere, the greenhouse effect would not work so I hope you are not “Denying the adiabatic lapse rate”.
Finrod,
I don’t know where you got the idea that I was “denying the greenhouse effect”. As a physicist I have no problem with radiative forcing. It is just a question of getting the numbers right.
I got that idea from the links you included, and from your comment about temerature dropping with altitude on Venus. Of course a mountain sticking up into a cooler layer of the atmosphere will be cooled by it. What has that got to do with the greenhouse effect?
But if you are conceding the existence of the greenhouse effect, then fine.
You said “So Steve’s post is not just slightly wrong, the conclusion is completely wrong. The heat on Venus is caused by the greenhouse effect.”
No, that was said by the commenter known as The Blob. I am not that person.
Actually the heat is coming from the sun and the “greenhouse effect” is helping to retain some of it.
Thanks for clarifying that. Up til now I’d thought it was moonlight driving all of this.
Without layering in the atmosphere, the greenhouse effect would not work so I hope you are not “Denying the adiabatic lapse rate”.
Carbon dioxide absorbes infrared photons and increases its rate of thrashing around, transferring that energy to other molecules through collision, thereby raising the temerature. What is it about unlayered atmossphere which suppresses this mechanism?
Finrod, YHBT.
Finrod, YHBT.
An unhelpful comment. As long as people are still pushing this nonsense, a response is occasionally needed.
Some feedback effects can kick in as fast as Western governments perceive them to be necessary.
My variant of Schuiling’s proposal is to use, per mole of targeted atmospheric CO2, 40 kJ of nuclear primary energy (13 kJ of electricity) to pulverize alkaline earth orthosilicate and 10 kJ to fling it into the sky.
That’s enough kinetic energy to lay it onto a suitably chosen trade wind 5 km above the flinger, and the pulverization energy is enough to make grains that settle at about 6 cm/s. Where the grains alight, they will, over approximately the next year, be consumed by, and consume, atmospheric CO2.
The energy inputs per mole of sequestered CO2 will be half what I wrote above if the alkaline earth carbonates that this produces dissolve in the ocean as bicarbonates. When I discussed this on RealClimate two years ago, the thread ended with a (n apparent) chemist assuring me this would make no difference, but I still don’t see how that can be true.
(How fire can be domesticated)
Southern Australia may record one of the warmest autumns ever
http://www.bom.gov.au/announcements/media_releases/ho/20100503.shtm
Should the trend continue it will affect agriculture, for example the cool weather dormancy period required by plants such as apple trees. If southern Australia gets increased summer rainfall (interspersed with heat waves) it could greatly affect grain production which is the source of much of our calories. On the positive side you won’t see so many obese people.
Try this link
http://www.bom.gov.au/announcements/media_releases/ho/20100503.shtml
Some decent (approximate) physics:
http://bartonpaullevenson.com/Greenhouse101.html
http://bartonpaullevenson.com/NewPlanetTemps.html
@ Dv8,
Dude, I take back anything I ever said about your naysaying wowserism. Terraform Venus! Forget asteroid mining for space-solar, you’re more of a techno-utopian than I am! Excellent. We are brothers!
eclipsenow- The difference of course, is that I’m not betting the farm on it.
Hi Finrod,
when quoting someone can you please use the following code (just delete the spaces) and it will make it clear to everyone when you’re quoting. I’ve used italics in the past, but I think blockquote is much clearer, so I’ll try to remember to use it in the future. Cheers.
D’oh! The code didn’t come up, must be actually reading HTML 5 or something…. just substitute blockquote for the i in the code, and you’ll get a nicer looking quote. Cheers.
If the Venus syndrome ever started to look serious, surely we’d:
* ramp up the biochar to sequester the carbon in our soils (but this is a slower and long term process)
* ramp up the sulfur
http://en.wikipedia.org/wiki/Stratospheric_sulfur_aerosols_%28geoengineering%29
It’s cheap ($50 billion a year compared to the world economy of $70 trillion a year! EG: even Australia could afford to do it if we Abolished the States and put the difference in cost straight into our own sulfur program!)
* In a REAL emergency (extinction of all life on earth becoming probable) use Nukes!
Just nuke something repeatedly until the dust does the job for us. Or pick the world’s most ‘fragile’ volcano, and nuke it till it blows? For that matter, if global warming ever became that bad wars would probably break out over other issues (like water rights etc) and we’d probably nuke each other anyway… bringing on a nuclear winter and reducing the number of ‘polluters’.
However, all of this assumes we don’t get the message when peak coal kicks in and have a REAL discussion about energy. When that happens, I imagine the biochar and energy strategies will grow exponentially beyond anything any of us could imagine.
Consider the Drake Equation, which estimates the number of technological civilizations in the galaxy based on things like number of planets, probability of habitability, lifetime of a typical civilization, etc.
Reasonable estimates for the parameters suggest there should be a detectable number of civilizations in our observable volume of space. Yet none have been detected. This is the Fermi Paradox, or as Paul Davies recently referred to it, “the eery silence”. Why is there no one out there? I attended a technical talk last year by Jill Tarter who runs SETI, and believe me, its not for lack of sophistication or scale in searching.
Sagan and others have speculated technological civilizations are necessarily short lived because they are doomed to destroy themselves, usually through war. But is it actually possible for a technological civilization to arise without destroying its planetary chemistry?
Its probably unlikely life could appear without liquid water, so that presumes a planet in the liquid water temperature range over abiogenesis timescales, which seems to imply some mechanism of temperature stabilization – some climate negative feedback effects.
Its probably impossible for a civilization to develop to the point where it can be broadcasting radio signals without exploiting concentrated energy resources. That means chemical energy. That means combustion. There’s no plausible non-carbon abiogenesis scenario, so that means burning carbon, or possibly some other combustible resource depending on the local chemistry – sulfur, phosphorous, boron.
Doing civilization is doing chemistry, at planetary scale. It will take a minimum quantum of energy to advance life to the point where it is broadcasting radio waves. At that point the civilization will be drawing a minimum amount of power. From chemical sources, producing a chemical output. This will be changing the intensive variables of the planetary system – composition, temperature, pH. This will be moving the system, and relying on stabilization mechanisms to act in response. The lucky civilizations will be those with a sufficiently deep stabilization well that they either run out of fuel before they run out of buffer, or can transition to non-chemical energy.
Where did everybody go? Maybe they just burned themselves out.
John Morgan – The Drake Equation’s predictions of the number of civilisations on other planets is very sensitive to initial assumptions. Low end estimates suggest that as few as three technological civilizations might exist per galaxy at any given time, and they may be separated such that they will never come in contact with each other despite millions of years of cohabitation.
Thus I would not draw too many conclusions from the lack of contact with off-world species.
John, I’ve mused about the Fermi Paradox before on BNC, here:
Carbon Targets I – Fermi Paradox solved?
That’s where I recycled the term ‘carbocide’ from – nothing more than a theory, but perhaps no less plausible than most others.
DV8 – I don’t. The Drake “Equation” can’t really be quantitative, but its an interesting scaffold on which to arrange some thoughts.
Barry, I’d forgotten that, or it might have been before I’d started reading your blog.
By the way, in checking the Fermi Paradox on wikipedia, I also came across Fermi Problems:
I’ve never heard it called this before, but this is what I do whenever I’m trying to understand something new. This is a very good description of your analytical approach, exemplified in many of the TCASE and IFRFAD articles. And I would say that it is the ability to think in this mode that separates those of us who “get” the analysis from those who don’t – Marcus, EclipseNow, Gloor, Lalor etc. I wonder if there’s some pedagogical insight there, but if so it eludes me.
Finrod,
In an earlier post you asked a question:
“Carbon dioxide absorbes infrared photons and increases its rate of thrashing around, transferring that energy to other molecules through collision, thereby raising the temerature. What is it about unlayered atmossphere which suppresses this mechanism?”
The greenhouse effect works because the outer layers of Earth’s atmosphere that radiate efficiently to outer space are at very low temperatures (typically, less than 230 degrees Kelvin). The amount of radiation follows the Stefan-Boltzmann equation that states that the energy radiated from a black body is proportional to the fourth power of the absolute temperature. This means that the cool outer layers radiate much less than the much warmer surface does (averaging 285 degrees Kelvin), ensuring a net retention of energy in the lower atmosphere.
If the radiating layers were at the same temperature as the ground, the outgoing radiation would be the same as for a planet with no atmosphere at all. In other words there can be no greenhouse effect unless there is a negative temperature gradient in the dense part of a planet’s atmosphere.
While the greenhouse effect is well understood in a qualitative way it gets controversial when you try to quantify the effect. Currently the “experts” (folks with more advanced degrees than I) have published results ranging from 0.5 to 4.5 degrees Kelvin/doubling of CO2 concentration in the atmosphere. While that is quite a large range of uncertainty there is another source of uncertainty owing to “feedbacks” such as the effect of water vapour and clouds.
The latest satellite measurements on Earth’s radiation balance show that “feedbacks” reduce our planet’s sensitivity to radiative forcing compared to the assumptions in the IPCC’s climate models.
The latest satellite measurements on Earth’s radiation balance show that “feedbacks” reduce our planet’s sensitivity to radiative forcing compared to the assumptions in the IPCC’s climate models.
Only a fool would wager the future of the planet on ill-defined and unquantified feedback machanisms which may or may not save us.
Surely peak fossil fuels will change the economics of coal before we burn it all.
If Ian Lowe and his mates believe this extreme scenario is likely, then why aren’t they pushing to remove all the impediments to nuclear power and arguing to subsidise nuclear rather than renewables?
Why aren’t Ian Lowe and his ilk pushing for a Manhattan type project to get us off fossil fuels.
One thing for sure, arguing to put up the price of electricity through adding a carbon tax is not going to speed up the rate the world moves to clean energy!! It will slow progress. We’ve already wasted at least two decades with these groups blocking nuclear while raising alarm bells about climate change. When is the penny going to drop for these anti-nuclear groups.
The solution is so obvious that it would seem these anti-nuclear groups have other agendas, as DV82XL and others repeatedly point out.
Barry, I hope you can get this point across to Ian Lowe.
thought that this was relevant
http://www.sciencedaily.com/releases/2010/05/100504155413.htm
uninhabitable by 2150?
@J Morgan re: http://bravenewclimate.com/2010/05/09/clarons-despair/#comment-64055
re: your attempts at patronising NPP sceptics in regard of the Fermi paradox.
At Fora.TV there is a nukie video lecture by a US journalist called Tucker from 2008. He relates at 1:03.13 how he interviewed the head of Solar within the US Dept. of Energy. This fellow said he thinks nuclear and solar are complementary. So he had been trying (as of 2008) to get nukies and solars within DOE to talk to each other for 15 years and they just refuse. The former think the latter are Hippies and the latter think the former are Nazis (quote).
This terminology shows the social divide I referred to as “halo effect” on another thread, notwithstanding Finrod casting doubt upon it in his answer on that thread.
BNC cf. its apparent approval of corporate apologist Hayden Manning, provides ample evidence of same. Nor has BNC decided (see recent debate on IFR versus other types of NPP) if it wants the IFR or some other Gen IV NPP or is quite happy, on grounds of C02 reduction, with the current Gen II as in Germany, let alone Gen III.
So the matter of international control of pyroprocessing and nuclear proliferation (see IFR intro by S. Kirsch or the GREAT suggestion of T. Blees) gets fudged. A casual visitor to BNC cannot be clear about what line is being taken.
Closing, remember Geoff Russell’s comment which amounted (as I recall) to saying that Green PV and wind energy lovers are needed to stop the coal being dug up at all.
That is, I don´t see many nukies in business suits and ties and yellow hard hats and carrying clipboards chaining themselves to Hunter Valley coal railway tracks in NSW.
QED.
re: your attempts at patronising NPP sceptics in regard of the Fermi paradox.
75% percent of each of your posts Peter are patronising gibberish, and no exception here.
The former think the latter are Hippies and the latter think the former are Nazis
I think you fall in the latter camp. On the other hand, I think the hippies are well represented in the nuke camp here.
A casual visitor to BNC cannot be clear about what line is being taken.
Theres no line being taken, its whats known, outside of tightly controlled, politically correct circles, as a “discussion”. Google it.
I don´t see many nukies in business suits
I’ve never worn a business suit to a protest, the dry cleaning would break me.
Antice – there is a subscribe button in the top, left-hand corner of the page!
Finrod, on 9 May 2010 at 15.15 Said:
“Only a fool would wager the future of the planet on ill-defined and unquantified feedback machanisms which may or may not save us.”
Well said! Now I agree with you.
Debating with Finrod made me realise that there is no need to speculate about the temperature gradient in Venus’ atmosphere. Someone in the USA or Russia must have measured it. A little surfing on the Internet turned up a 15 year old graph (Jenkins, 1995):
http://www.astro.wisc.edu/~townsend/resource/teaching/diploma/venus-t.gif
The graph shows a nearly linear fall in temperature up to the tropopause at ~60 km compared to ~15 km on Earth.
There is a “Goldilocks” zone on Venus but it occurs at an altitude of over 50 Km!
It turns out that Steve Goddard’s speculation is not news after all.
The following article has an interesting chart showing the annual risk of death by age and gender in the UK:-
http://www.medicine.ox.ac.uk/bandolier/booth/Risk/dyingage.html
Death is a minor but real risk for most of us. Young women seem to be the least at risk. The rest of us have an annual risk of death way higher than one in 10000. We could be hit by a bus any day now. Yet if I threatern to build a nuclear power plant in your suburb with a chance that it will blow up and kill everybody once in a million years this worries people. A miniscule increase in everybodies risk of death is somehow a terrible thing if the risk in question entails a synchronized death. Individuals dieing at a high rate is nothing compared to a tiny risk of everybody (in your suburb or city or airplane) dieing at the same time. I suspect this attitude is a consequence of our selfish genes. Death of the self is less significant than death of the tribe.
When it comes to the extinction of our species we really get upset. However if you get wiped out by a bus then whether the earth gets destroyed a year later, or doesn’t, really doesn’t matter (to you) even if you think otherwise.
I don’t think people are logical when it comes to risks. On collective risks (ie synchronized death with the neighbours scenerios) they are even more illogical.
p.s. Putting this another way. If we are all fool enough to wager our lives (eg ride in a car) for a little comfort and convienience then why shouldn’t we collectively wager the planet for some collective comfort and convienience.
TerjeP,
As you point out, life is risky! Even so, it is worth designing safer nuclear power plants to reduce the risk of fatal accidents.
There are reactor designs that are potentially much safer than PWRs such as the RBMK. Several of them have been discussed on this blog,
One example is the Liquid Fluoride Thorium Reactor which is not subject to Chernobyl style failures. Here is a link to a fun video on LFTRs:
Here is a link where the pros and cons of LFTRs is discussed:
http://energyfromthorium.com/joomla/index.php?option=com_content&view=article&id=64&Itemid=63
Fast moving camel,
I don’t mind spending money on safety. However the cost and the benefit need to be considered. Low costs improvements to safety make some sense.
My main point was that risks that impact on us individually are not given as great a concern as risks that impact on us in a synchronized social tragedy. We don’t get much public debate about that red bus with your name on it.
In terms of betting the earth I don’t think the wager is necessarily that foolish. If I offered you a magic button that would enable an instant and sustained ten fold increase in the per capita GDP of the worlds 100 poorest nations then who wouldn’t want to press it. If there was a 1 in 10000 chance that pressing the button would instead destroy the planet I’d say that at those odds it would be folly not to press the button. Betting on the future of the planet seems quite reasonable to me if the odds are right.
TerjeP @ 10 May 2010 at 5.53
You make a good point that we evaluate the risk of death to an individual differently to the risk of death of many people at one time.
However, our evaluation of the risk of death from a nuclear accident is still irrational. Because even the worst accident ever did not kill or harm a large number of people compared with other frequent accidents. Nuclear accidents when they do occur may cause a small number of fatalities and a relatively small number of latent fatalities. I say ‘relatively small’ because I am comparing with the much larger number of fatalities that are caused by the routine operation of the alternative sources of power. I am also comparing with the consequences of accidents from our chemical industries. These industries are spread throughout our cities and are only lightly regulated when compared with the regulations on the nuclear industry.
So I argue that the population’s fear of nuclear energy is a totally irrational one.
And this irrational fear of nuclear energy is delaying us moving to low cost, clean, safe electricity supply. I hold the Green groups as largely responsible for the delay in progress on this.
gallopingcamel, on 10 May 2010 at 7.12 Said
This is illogical and irrational. Gen II PWR’s are already 10 to 100 times safer than coal and far safer than the other industries. The PWR’s are also too expensive because of all our over design and over regulation. So they don’t get built. So we keep building plants that cause 10 to 100 times more fatalities per unit of energy supplied. Asking for more safety for the safest plane we have is irrational and illogical if by doing so we prevent them being built at all. And that is exactly what we are doing, and have been doing for the past 40 odd years.
TerjeP
The cheapest way yo improve safety of electricity supply is to remove the impediments on nuclear that make it more costly than coal in western countries. Allow nuclear to compete with coal, and replace coal. That would be the least cost way to improve safety and also reduce emissions. If we allow nuclear to become low cost, as it should be because of its high energy density, it will more rapidly replace coal world wide. That is the route to the reducing world emissions fastest.
DV82XL- You don’t have to terraform Venus to live there, just stay high enough in the atmosphere to keep the temperature manageable. Habitat could be carbon ‘ teratubes’, with most of the oxygen vented out, a couple of pounds partial pressure of oxygen inside and enough nitrogen and maybe helium for buoyancy and good breathing. Might be a more benign environment than space in some ways. If that’s not doable you could boost them into orbit and spin them up for gravity. Hope we never have to do it here though…
On the subject of risk, lets consider some possible outcomes depending on paths chosen and upon who ultimately turns out to be correct concerning AGW.
Suppose we end going with one set of technologies dominating our energy industry in the manner fossil fuels do today. Consider the outcomes for a world based mostly on renewables, fossil fuels or nuclear fission. What are the outcomes, depending on who was right or wrong about AGW? The following is a brief summary of my opinions:
Renewables, AGW false:
Industrial civilisation collapses, billions die, humanity takes centuries to recover and rebuild after the overthrow of the pro-renewables regime.
Renewables, AGW true:
Industrial civilisation collapses, humanity helpless in the face of climate change, possible extinction.
Fossil fuels, AGW false:
Business as usual, present system continues on for a few decades until growing fuel shortages and rising demand force a changeover to nuclear power, some economic disruption possible if the switch to nuclear is delayed too long by fossil fuel interests. No great cause for concern.
Fossil fuels, AGW true:
CO2 continues to build up in the atmosphere until either the signs of warming are so plain that denial is no longer possible, or until fuel shortages force the switch to nuclear power. The maximum possible amount of CO2 from FF burning has been added to the atmosphere, and the world must cope with a more severe problem than was necessary. The only way to know how severe that problem will be is to run the experiment.
Nuclear fission, AGW false:
There is a minor negative impact on the world economy caused by allocating resources to swithching to nuclear power a few decades earlier than might have been absolutely necessary (although it can be strongly argued that it’ cheaper to do so even now), but the situation improves rapidly as nuclear fission’s long term advantages start to have an impact. Valuable carbon reserves no longer slated for the furnace are now available as chemical feedstock.
Nuclear fission, AGW true:
The carbon dioxide which would have beed in the atmosphere had fossil fuels continued being burned is eliminated, and the world has a robust energy supply to assist in whatever measures are deemed necessary.
I dunno… which of the above do people prefer?
@ Finrod:
What, this is the result if we go down the renewables path? Hilarious doomerism on the order of Mike Stasse. Come on Finrod, a renewable grid might be a lot more expensive than a nuclear grid, but surely it isn’t the end of civilisation as we know it? (TEOTWAWKI)?
@Finrod – Ya, that’s been my general reasoning too. Beyond this of course is that nuclear is the only viable path out of poverty for the Third World, as they simply cannot take the same route we did.
Just for the record: I’m in a debate on wind with the Climate Crock guy here.
His climate stuff is great, but I’m just there to jog people’s memories about some of the other issues with wind, which Climate Crock recommended as a power source. I’m engaging the big-picture questions only (EG: At 30% capacity, doesn’t that mean it will cost 3 or 4 times as much to ensure baseload, especially if we talk about building solar for the day, wind for the evening, etc).
However, ultimately if costs come down enough on a few storage technologies… who knows? I remain ‘agnostic’ about which energy source will win, while being quite ‘enthusiastic’ about nuclear for now.
What, this is the result if we go down the renewables path? Hilarious doomerism on the order of Mike Stasse. Come on Finrod, a renewable grid might be a lot more expensive than a nuclear grid, but surely it isn’t the end of civilisation as we know it? (TEOTWAWKI)?
EN, if we try to tun the world with ‘renewable’ energy, Haber-Bosch will be a thing of the past, modern agriculture will no longer be possible on the scale needed, food production will collapse, and billions of people will die.
Biochar can probably supply enough liquid fuels for agriculture (and massively reduce the need in the first place for NPK fertilisers), wind can run Haber Bosh, solar thermal & geothermal can run stuff. It’s doable, but according to the arguments here just more expensive.
D’oh! Biochar provides syngas, which would probably be more efficient straight in the harvester, than using MORE energy to actually turn it into synfuel. By “liquid fuels” I meant anything you can burn in a harvester or tractor, including jerry-rigging the tractors to run on gas.
Finrod, on 10 May 2010 at 9.47 Said:
“EN, if we try to tun the world with ‘renewable’ energy, Haber-Bosch will be a thing of the past, modern agriculture will no longer be possible on the scale needed, food production will collapse, and billions of people will die.”
Which is why this will never happen, and why the whole ‘renewables’ meme is a fraud. It depends on the ignorance and innumeracy of the audience to get any traction. Once anyone looks at the numbers critically with some awareness of just how dependent we are on electric power beyond lighting our homes, their support for renewables vanishes.
Everybody that counts know the truth -everyone- and that is why this renewable fraud is nothing more than greenwash for more FF use. It is just that simple.
Quite right DV8
Finrod’s exercise was purely theoretical — an attempt to get past the practicalities to the end point, so as to interrogate the reasoning.
Really, in practice, we will never have industrial scale renewables on a global basis, because on cost-benefit, schedule and operational grounds, they are simply not viable at that scale. Some places — Iceland for example, are especially lucky and can get away with it, but these can’t be a general solution.
Rather they are a feel good solution that will cover the reality of extended fossil fuel usage — and so become a variant of Finrod’s other options.
I thought Finrod left out some of the benefits of nuclear fission in his AGW false scenario — and these are the local environmental impacts — where you immediately get a much cleaner airmass and zero contamination of the local land, waterways etc, with all of the positive health effects on humans these imply. Indeed, the amenity of an area is improved by something as simple as having fewer trucks transporting feedstock to the plant, as is the amentity of the coal delivery chain. This very much applies in China where coal is transported long distances. If coal were abandoned as an energy source in the US in favour of nuclear, about 40% of heavy freight on rail would be freed up.
So regardless of AGW, humans start benefiting immediately a thermal fossil plant is retired in favour of a nuclear plant. Indeed, this remains true even if the plant an NPP replaces is waste biomass, since that too has its own footprint.
.
Oh I understand what was being said, I was just adding to it. Like I often say: when I see a base metal smelter running on wind I’ll believe…
I thought Finrod left out some of the benefits of nuclear fission in his AGW false scenario — and these are the local environmental impacts — where you immediately get a much cleaner airmass and zero contamination of the local land, waterways etc, with all of the positive health effects on humans these imply.
That’s true. The list I came up with was in response to the economic concerns the anti-AGW faction sees as paramount. If I had been engaging with renewables advocates, my list would have been a little different.
If I had been engaging with renewables advocates, my list would have been a little different.
Sorry, just to clarify, that’s because I assume the average renewables advocate would be more concerned about environmental impact than economic cost (or would at least claim they were).
Peter Lang,
Nuclear power is presently making a significant contribution to reducing CO2, and hopefully will make even a larger contribution in the future. The only threat to this happening would be a major accident because some foolish government decides to cut corners to either reduce costs or speed up construction.
The number of people killed by such an accident will not be relevant. The risks are similar to airline industry, we dont shut down airports because plans drop from the sky and kill passengers, but we would (and have) if most of those airline accidents result in planes regularly dropping onto major cities. People can accept the risk of going into a mine, fishing or farming, or flying but the general population doesnt want to share in those risks on a day to day basis.
If you are making the argument that we can only have nuclear power with lower safety standards then you have lost the argument with the general population.
It seems to me that nuclear power with present worlds best practice is viable and should be promoted, but we have to live with the longer build times and slightly higher costs. Standardized design can both lower costs and build times without compromising safety.
Which, Neil Howes, is the position I persistently put to Peter Lang and which he, for reasons that remain elusive, rejects.
I have an observation on the nuclear safety issue in relation to air travel. In the Fifties and Sixties a crash was a major issue for all airlines, because when that happened all carriers took a major hit in traffic. Traffic would drop for months before recovering. This phenomenon stopped in 1974 when Turkish Airlines Flight 981 went in.
I was working for an airline at the time and everyone braced themselves for the drop in traffic. Everyone from fuel purchasing, to crew scheduling, stated to recalculate based on the expected fall, and this was going on across the industry.
And in the end that shoe never dropped. The public had just folded the risk into their thinking, just as they had for other forms of transportation. Over time this will happen with nuclear.
Maybe it will DV8, as ‘over time’ could mean a very long time.
But it might prove disastrous for our challenges today if a major new accident occurred right now. Now is when we need to have the public debate in a public space unclouded by another Chernobyl.
PS: Also, how can you compare a few hundred dead compared to a city and region abandoned for a few hundred years?
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.
Second, it only took twenty years for Europeans to forget what Total War meant before they went at it again. Collective memory is no so reliable in these cases.
Third, the DC-10 has killed over 1,261 people to date, in some 30 hull-loss accidents, which is comparable to similar second-generation passenger jets, and people still fly. How many has Chernobyl killed?
Neil Howes,
I think you have missed a lot of the background to my comments about the irrational imposts on nuclear power. These imposts are causing nuclear to be, perhaps 4 times more coslty than it needs to be. By requiring nuclear to be 10 to 100 times safer than coal fired power, we are preventing nuclear competing as it should. So by requiring ridiculous levels of safety, we are preveniting us getting trhe benefits of nuclear. It is an irrational discussion. I agree wtih you that we have a mjor public perseption problem, but that is what I am arguing we need to address. IMO we should not continue to burry the problem.
By the way, I posted another respponse to your comment about the project you have been working on. I wonder if you saw it. It is here: http://bravenewclimate.com/2010/01/09/emission-cuts-realities/#comment-63258
This may also be relevant to what you are working on: http://bravenewclimate.com/2010/04/05/pumped-hydro-system-cost/#comment-64083
Ewen Laver,
Ewen, the reason my argument remains elusive to you is because you haven’t really tried to understand it. You are trying to put your own argument, and continually repeating it, before you’ve even tried to understand mine. Your argument is based on your beliefs about current politics, as if these beliefs will last forever and should drive our decisions forever. However, in my opinion those beliefs are irrational. I am trying to urge people to think rationally and make the right decisions for the long term. I understand where the population is at with nuclear. But I’ve also spent time in Canada and Sweden and elsewhere where a rational discussion can be held on these topics. So I know these currently held beliefs can cnahge. In fact I believe they will change. I am trying to facilitate that to happen faster.
You have never answered how you justify requiring nuclear to be 10 to 100 times safer than coal, and therefore to cost probably 4 times more than it needs to. You don’t seem to accept that higher cost electricity will slow the rate of uptake of clean, safe power world wide. You don’t seem to appreciate that our ridiculous requirements are causing nuclear to be much more expensive than it needs to be. For some reason you just don’t seem to be able to follow this line of reasoning. You seem to get stuck on the fatalities that coal causes but cannot see the whole picture in a balanced way. The arguments you are putting are the ones have been blocking progress with nuclear for 40 years. And yet you persist with them.
We’ve been through this numerous time on BNC so there is little point in me trying to explain it to you again. If you want to try to understand the point I’ve been making then please look back over where I’ve explained it before. I can’t see any point in you and I writing any more to each other on this topic. I am happy to discuss it with others, but I think you and I would be wasting our time discussing it any further.
DV8,
I appreciate that you need a theme song for that mantra because I’ve had to sing it myself… a ‘Chernobyl’ event can’t happen the same way again, because we actually build containment domes in the west.
But when a tricky terrorist “Black Swan” unforeseen event takes out one of these domes and blows radioactive crap all over Brisbane, we’ll say “Boy I hope that a Brisbane event never happens again!”
Then when we build the ‘super-dome’ and some sneak invents the ‘super-dome-buster’… well, etc. Technological proliferation of defence and attack technologies will hopefully make each generation of domes harder to crack…
But my point is never say never so arrogantly.
PS: I’m not using any of this as an argument against nuclear power itself. If we want a modern technological civilisation, that comes with a certain level of risk.
EN, how combustible is your water in Brisbane?
It’s not arrogance, it’s science, as Peter’s comment is meant to indicate. Phrased in another way, I could ask: “where’s the graphite?”
eclipsenow – To postulate a <"tricky terrorist “Black Swan” unforeseen event" and be taken seriously, you have to extend a credible mechanism how this could happen. Anyway cracking a dome isn’t enough in and of itself to cause a radiological event. Modern NGS use defence in depth, and your attackers would have to be able to break several lines of defence before getting at the core. We can safely assume that there would be efforts to interdict them after they made their first penetration attempt. Thus the likelihood of prosecuting such an attach successfully is low.
But just invoking terrorists with black swans to me is the same as invoking the bogeyman with a bag of tricks, in that it seems to be used as a rhetorical tool to drop logic for wild speculation, which really has no place in this debate
Peter Lang, TerjeP & DV82XL,
You seem to be in tune with Barry Brook on energy policy so you all will get my vote if you run for office.
Commercial aviation has an amazing safety record; one of the few human endeavours that comfortably achieves a 6-sigma quality standard (3.4/million) when it comes to the probability of being killed on a scheduled airline flight. Even though the standards are so high there are still 1,000 to 2,000 airline fatalities each year.
Nuclear power plants are arguably much safer than airlines in terms of annual fatalities and yet the perception among the general public is that nuclear power is dangerous. While I regard the fear of nuclear power as irrational it still makes sense to improve the cost and safety of nuclear reactors through innovative design.
As this thread started out discussing the high surface temperature on Venus this question may be “off subject” but here goes:
What would you say if someone offered to install a small nuclear reactor to serve your community?
The reactor would be built in a factory and delivered to site on a single 40′ truck. The power capacity would be <75 MWe. There would be no high pressure containment structure as the reactor operates at 1 atmosphere pressure. There would be no nuclear containment structure as the reactor would be incapable of suffering a criticality accident. The power generated would cost you 7 US cents/KWh and there would be no cooling tower or chimney.
Assuming that you lived a few blocks from the proposed reactor site, would you vote for it or against it?
Peter
I share your view that we shouldn’t redux our old argument. Your position on costing (opposition to internalisation) is clearly a matter of faith and thus impervious to reason.
That said:
You assume that in practice cutting nuclear safety to coal safety would actually save a substantial portion of these costs. There’s simply no evidence at all for this. Most of the regulatory burden bears no more than notional pertinence to operational safety and those that do are minor factors.
Most of the cost saving in nuclear would be achieved through standardisation of design and mass production.
Your most important error though is to foreget that reason in this debate is an innocent bystander. Politics is about rrade in the right to mobilise political behaviour. Inviting swinging voters who understand almost nothing about how nuclear pwoer works to weigh up the calculus of safety and vote their side of a risk trade with cost and the relative appeal of coal would never, could never stop one side wedging the other on this isue enough to lose. Yours is a recipe for never having nuclear power taken seriously. Renewables will always be the gleaming example in that context as some moron shouts “No more Chernobyls … what price safety?” or “Renewables not Chernobyls!”
Personally, I’d sooner sell nuclear power as expensive precisely because it is safer than coal.
Finrod – your set of scenerios is a bit crude and the odds ought to be better quantified but I don’t have any real disagreement with where it is headed. I’m an AGW sceptic but more so to the extent to which AGW is a problem than as to whether it is a real phenomena. Obviously it could be a big problem and cheap solutions such as a switch to nuclear power have a lot of merit especially given that there are few if any regrets in such a transition.
p.s. But in principle we should bet the planet if the odds are good enough. Worst case we end up extinct a bit earlier than expected.
Worst case we end up extinct a bit earlier than expected.
When do you expect this?
Finrod – your set of scenerios is a bit crude and the odds ought to be better quantified
I wasn’t trying to make an ironclad case for my own particular set of opinions (they’ve been made elsewhere), so much as set out a scenario matrix for the consideration of and debate concerning various options. If the matrix itself is considered valid as a framework within which the discussion should take place, then my intention is accomplished. I’m well aware that others rate the cost/benefit of these option differently, and that a more in-depth analysis is necessary for the resolution of disputes about the correct value for each option.
Concerning the original topic of this post: James Hansen’s book and the “Venus Syndrome” — does anyone have a comment or observation about Dr. Roy Spencer’s latest series of posts and published (forthcoming issue of Journal of Geophysical Research) article on radiative forcing and climate sensitivity?
http://www.drroyspencer.com
Always appreciate a reasoned response.
gallopingcamel, on 10 May 2010 at 13.16 Said:
For me the issue is cost, not safety. I have no problem at all with having NPP’s wherever they should be located for least cost electricity. That includes being near where I live. I am sure the the chemicals at Fyshwick and Hume nearby are far more dangerous, and far more likely to leak and far more likely to cause fatalities and illnesses than a small or large NPP. I am also sure that Googong Dam, just up stream from us, is more likely to break and drown thousands of people than is the likelihood of an NPP doing anywhere near that level of damage.
So safety is not the issue for me. The sole issue for me is the cost.
You ask would I vote for this NPP if: “The power generated would cost you 7 US cents/KWh?”
The question is not clear to me. Is this the cost of the electricity that the power station needs to recover (the Levelized Cost of Electricity (LCOE)), is it the average wholesale price the NPP sells it for, or is it what I, a householder, has to pay? If the latter, then it is about half the price I pay now. So that would be a good deal. If it is the LCOE, then it is twice the cost of electricity from our coal fired power plants. So that cost is too high and is not competitive. There may be other factors involved and it may still be a good deal at LCOE = 7c/kWh. However, I believe nuclear power in Australia should be no more than the cost of new coal, (say 5 c/kWh) and far less than the cost of new Combined Cycle Gas Turbine. I believe this is definitely achievable and is what we should aim for.
Give the engineers a clearly defined goal and they will achieve it. The task I would set them is:
Provide clean electricity at a cost less than from coal with safety not less than from coal.
Ewen,
Look in the mirror.
Well go and join a coo-op with a group of your mates and buy your own NPP then. Or a windmill. But don’t try to force your irrational beliefs on others. A few like yourself may be prepareed to pay twice as much for the same product, but most wont.
Ewen, You simply don’t understand. You keep rehashing the same nonsense that I and others have shredded about ten times. You simply don’t get it.
You keep saying Peter that you have “shredded” my arguments, but repeating this claim won’t make it so.
You are the only one who is stuck on this point as a matter of principle, so it’s hard to imagine who the “others” are. DV8 made some points on getting down costs which I endorsed.
You alone want to reduce the safety of nuclear so it will be no better than a coal plant. Good luck selling that idea.
Hopefully, nobody who isn’t in favour of NPPs will hear this pitch because you would definitely damage the credibility of the campaign. If I believed you were serious I’d prefer coal. Luckily, I know this is just some blindspot you have.
Safety and environmental benefit is our selling point and you want to cast it all away for … nothing.
Amazing.
Seeing as we are once again discussing NPP safety, I was wondering if anyone could answer this question: –
Is Methyl isocyanate (MIC) commonly used in pesticide production today?
This was the chemical which was responsible for fatalities in the Bhopal disaster – which killed at least 100 times more people than Chernobyl.
If the answer to the question is yes, we probably have pesticide production facilities using MIC in many of the cities we live in.
Perhaps we could tactically shift the fear mongering to the pesticide industry, and people will forget their fears of nukes. (I’m not actually being serious here)
Ewen, Peter, probably best to be revising this debate in the Open Thread or one of the NP-focused ones.
DocForesight, Hansen’s view (and mine) is that the most powerful evidence on feedbacks, +ve and -ve, is paleohistory, and these data have consistently indicated a relatively high degree of sensitivity (i.e. a predominance of +ve forces) which can only be counterbalanced by compensatory feedbacks over the long term. Right now, the forcing is so rapid that the -ve feedbacks are likely to prove inadequate on any timescale we’d care about.
But Teekay it is a good point, because to live in a modern civilisation is to accept some level of risk for various benefits. If the safety risks of nuclear power plants and waste storage can be explained in relationship to more everyday activities that people don’t otherwise blink at, maybe the word ‘nuclear’ can be demystified of its horror to these people.
(I kind of include myself in the last batch as I struggle through the waste issues… I’m still willing to learn more but time limits… which brings me to…)
Barry, any news on discussions with technical folk about running a regular podcast?
Barry: Why do you think the Venus Syndrome is unquantifiable and unprovable? People live David Archer are quite sure the syndrome is impossible … and they
have calculations to prove it. Hansen presumably agreed with these calculations
for a long time until he realised that some of the assumptions were
soft. But we may well get more accurate measurments of past climate
parameters, and we may well be able to put robust bounds on climate
predictions and prove the issue one way or the other … probably not in
our lifetime, but another 40 years of data and modelling might well solidify
the proofs .. one way or the other.
Teekay,
Yes, it is. You’ll also be delighted to know toluene diisocyanate and methylene diphenyl diisocyanate are major monomers in in polyurethane production (though less hazardous due to their lower volatility). I know of large (high volume production scale) tanks of these materials in Melbourne. A leak would be horrible.
I think the key messages that will help people to reconsider what they think about nuclear are of the following form:-
1. A nuclear power plant is less risky than a hydroelectric dam.
2. A nuclear power plant imposes less nuclear waste on humans and the natural environment than the coal fired powerstations we currently live with.
Sell those two ideas persuasively and convincingly and all but the ideologically committed will start to question ill founded beliefs. IMHO.
The problem I have with the Venus type outcome is why a Venus type outcome didn’t happen 400 million years when all the carbon was still in the atmosphere and not in coal beds? The thing is when you look at the thing quantitatively is that even if we dug up and burned all the economically recoverable coal, there is no way we could push the CO2 level past 1000ppm.
Even that would have to assume much cheaper ways of digging up coal than are currently available. It is important to remember that no one is going to bother to dig up coal and burn it if the energy to dig it up is more than energy generated by burning it.
1000ppm CO2 would be an environmental disaster, but no Venus.
Joel, the difference is the luminosity of the sun was much lower in the distant past, as explained in one of the quotes I give above. Hansen is very careful in explaining these apparent paradoxes in this book. The Venus Syndrome is not a hypothesis to dismiss lightly. And as I pointed out in closing, if we can say with 99% certainty that “1000ppm CO2 would be an environmental disaster, but no Venus”, leaving a 1% chance that “1000ppm will lead to runaway feedbacks [driven predominantly by methane clathrate releases] and elimination of all life on Earth”, then we have a serious risk management problem that we’re not paying proper heed to.
Sure, but as you pointed out in the article on why you love economics, and are not worried about anti-nuclear activists, the economic factors will ultimately win out.
So surely peak coal will stop us burning *all* that coal? The economics will shift towards nuclear somewhere after half-way, and as we all know, the University of Newcastle has placed peak coal somewhere between this year and 2048, while others are arguing peak coal is definitely earlier than 2048… more like 2025.
http://en.wikipedia.org/wiki/Peak_coal#World_peak_coal
This prescription seems aimed only at blocking sunlight, not at correcting the buildup of CO2 in the atmosphere.
Even for that SACTCAR objective it is ill-crafted: it uses excessive amounts of explosive nuclear energy to do a job that much smaller amounts of nuclear-generated electricity would do better.
Plus, you can, over a period of a few years, get a lot more energy out of a reactor that is not painstakingly designed to overcome fission’s natural tendency to self-control than you can from one that is so designed. You can even use unenriched uranium.
Each 150 thermal kWh of the much larger amounts of energy that reactors can provide, compared to bombs, can make 50 electrical kWh, and this can pulverize a tonne of an alkaline earth orthosilicate mineral such as olivine or wollastonite. Disperse enough of it in the upper air, by efficient electrical means, and sunlight will be blocked, and the planet will cool, but the oceans’ diminishing pH will not be corrected.
Disperse a much lesser amount, and it will soon — within about a year — snatch down, if I recall correctly, a tonne of CO2. And this will counteract all the effects of that excess CO2. So dust made from these minerals is much, much more effective than dust from a randomly bomb-dispersed bit of the Earth’s crust.
So a tonne of unenriched uranium, in reactors like those that today run on it, can power the removal of a million tonnes of CO2 from the atmosphere. The ~20 million tonnes U that are known to be recoverable from phosphate deposits are much more than enough to bring the atmosphere’s CO2 inventory back to what the planet is used to. (Much of the necessary energy doesn’t come from the reactors but from the mineral grains and the CO2 themselves, as <a href="Enhanced weathering of rocks“>David McKay says:
The nuclear energy serves only in a catalytic role.
(How fire can be domesticated)
Joel Upchurch, on 11 May 2010 at 9.15 Said:
QUOTE
1000ppm CO2 would be an environmental disaster, but no Venus.
UNQUOTE
Why should 1,000 ppm of CO2 be a disaster given that the planet had much higher levels for millions of years without any hint of a Venus syndrome? The idea that CO2 is the main climate driver is not supported by scientific studies looking backwards in time. To the contrary, the evidence shows that rising temperatures are usually followed by rising CO2 levels after a few hundred years.
Looking forward in time, the IPCC’s temperature “Hockey Sticks” (AR4) seem less and less plausible with every year that passes.
@ Camel:
This has already been *repeatedly* answered on this thread (if you bothered to read it). The sun is much warmer now than when we were last at 1000ppm Co2.
Also, you sound like you’re just recycling another of the top 28 denialist myths, the “Temperature always precedes and causes Co2 changes” strawman. Bottom line: while it has in the past, you’re still missing the point. (Lying with a half-truth is always more convincing, but still always a lie).
@ Eclipsenow
There is still debate on whether the sun was cooler in the past. Carl Sagan pointed out an apparent contradiction between observations of liquid water early in the Earth’s history and the astrophysical expectation that the Sun’s output would be only 70% as intense during that epoch as it is during the modern epoch.
See: http://en.wikipedia.org/wiki/Faint_young_Sun_paradox
There is still debate on whether the sun was cooler in the past.
Not much of one. The astrophysics is pretty solid.
I suspect that “Gordon” is another name for El Gordo who posts his own crafted denier talking points regularly on Deltoid.
If this is so, then the point he raises above has been answered many times there. El Gordo, when cornered, simply raises a new point hoping people will forget the old one he has run away from for long enough for him to pitch it again.
Accordingly, while people can do as they please, can I say at the start of the exercise that if Gordon really is El Gordo then he is a time waster.
No Fran, I am not El Gordo
@ Finrod,
Gordon believes in Abiotic oil, and, well, basically any fringe science, scientist, or ‘vague idea’ that will make peak oil and global warming go away for him.
He just doesn’t want to deal with reality.
Then he probably also doubles as a dozen other call signs and avatars for Denialists that I’ve met in other science forums, where EXACTLY the same immature tactics are used. It’s revolting when you think you’re in a conversation and then after another few posts start to smell the foul reek of swamp goo from under-the-bridge.
Discussing global warming must sound like “Tritt-Trott, Tritt-trott” to these people.
http://en.wikipedia.org/wiki/Three_Billy_Goats_Gruff
Gordo, just remember how that tale ends.
@Eclipsenow
No Dave, I am not El Gordo and thinking that I “lurk” in other science forums makes you sound somewhat paraniod – but hey, I already suspected as such. Speaking of immaturity, one only needs to look at your posting history of name calling to determine your level.
Yes the tale ended by the IPCC declaring goats as dangerous methane producers and recommending to world leaders they all be put down 🙂
Just on Abiotic processes maybe you would like to comment on this:
http://en.wikipedia.org/wiki/Mud_volcano
Up to 235 Tg/yr methane produced – from where?
Dude, I did not mean it was actually you in other forums, but was just making the observation that you Denialists all behave in the same way. Like now, pointing at a another thing (Mud volcanoes) because you can’t be bothered dealing with Co2′s magnifying effects of previous Milancovitch warmings.
Not that I expected an actual answer that would actually address the actual climate papers. Come to think of it, you never answered why if the world is running on abiotic oil, why don’t all the depleted wells refill?
But hey, at least you’re being consistent. Fran really nailed your number.
@ Eclipsenow
I didn’t raise a new point – I merely addressed the one that you had raised!
I thought we had already addressed the (lack of) CO2 magnifying effects of previous Milankovitch warmings with this:
http://oregonstate.edu/ua/ncs/archives/2009/aug/long-debate-ended-over-cause-demise-ice-ages-%E2%80%93-may-also-help-predict-future
The researchers concluded that:
“The melting was first caused by more solar radiation, not changes in carbon dioxide levels or ocean temperatures…..”
Well, are you going to address where all that gas is coming from?
eclipsenow,
You can repeat nonsensical arguments all you like but in the real world cause precedes effect. Anything else is sophistry.
Your argument about lower solar output does not fly over the last ~750,000 years (the extent of ice core proxies). The ice core proxies show temperature rises preceding rises in CO2 concentration. Although this does not prove that temperature drives CO2 concentration (correlation does not imply causality) it disproves the hypothesis that CO2 concentrations are the main driver of temperature on the 10,000 – 750,000 year scale.
Looking back many millions of years to times when the sun’s output was significantly lower than today, there were still ice ages and warm periods while CO2 concentrations averaged over 2,000 ppm.
While most scientists understand that CO2 concentrations raise temperatures at the Earth’s surface, quantifying the phenomenon is still subject to fierce debate owing to the complex nature of the “feedbacks” involved. You need to get over the absurd idea that CO2 is the main climate driver on any time scale on Earth.
From the comments earlier on this thread you should have picked up on the idea that the thickness of the atmosphere is a better explanation for the high surface temperature on Venus than Hansen’s “Runaway Greenhouse Effect”.
We seem to have a miscommunication about the timeframe I’m talking about. I’m discussing the conditions before the carboniferous periods when the coal beds were created about 400 million years ago. The faint young sun period ended about 2,500 million years ago. http://en.wikipedia.org/wiki/Sun#Faint_young_Sun_problem
400 million years ago the sun has already stabilized into pretty much it’s current condition.
The early Earth still hadn’t cooled yet and had a reducing atmosphere with a large Methane component which would have generated a greenhouse effect impossible to create with just carbon dioxide, since Methane absorbs a much wider part of the spectrum than CO2. The greenhouse effect is logarithmic with the CO2 content, not linear. Even if we quadrupled the CO2 in the atmosphere we are probably talking about warming in the 6-8 degree range Centigrade worst case. That would decimate the human race but not exterminate it, like a Venus type outcome would. Of course, the biological consequences of such an increase in CO2 would be unpredictable, especially over a timeframe of decades rather than millennia.
I hope most people would agree that something that might kill off between ten and fifty percent of the human race would still fall under the heading of a disaster that it would be highly desirable to avoid.
I frankly don’t think raising a Venus bogeyman is helpful. To convince people we should stick to real science and skip the fantasy stories. Climate science has taken enough creditability hits.
@Gordon and gallopingcamel –
Isn’t it fun to be the recipient of the “denialist” smear? Classy, that. By the looks of things at UN IPCC and affiliated groups, it’s getting harder to ‘corral the cats’ as more questions are raised and the computer models miss the mark.
Though I am involved in solar and battery back-up systems, nothing can compete with nuclear power for base-load. That the environment (in all respects – fresh water, clean air, less mining sites, less deforestation, greater economic development and security, etc.) would benefit from nuclear power is an additional and significant advantage.
400 million years ago the sun has already stabilized into pretty much it’s current condition.
Ignorant garbage. Astrophysical theory states that stars like the sun continue to brighten all throughout their career on the main sequence. This has continued all throughout solar system history and continues now, and shall continue up to the initiation of the red giant stage. It is this model which leads to the prediction that earth shall be pushed into a ‘moist greenhouse’ condition in about 1 billion years.
(yawns)
@ Gordon and Camel,
stop using Strawman arguments.
Maybe “Climate Crock” can explain the Milankovitch cycles relationship with Co2 for you, as the New Scientist article summing up the peer reviewed papers seems to have gone over your heads.
I mean, did you both get your ‘science’ from “The Great Global Warming Swindle” or something? Honestly! Martin Durkin was just jerkin his Gherkin!
Joel, 400 million years ago, the sun was roughly 4% less luminous than today.
http://solarb.msfc.nasa.gov/science/timeline/
That’s a considerable negative forcing compared to today, and must have been offset by something – such as increased atmospheric levels of greenhouse gases.
I have a question for you. How did Venus ever reach its hothouse state, given that the climate sensitivity is logarithmically related to CO2 concentration? Can you see a flaw in your extrapolation?
Barry,
The Venus Express team have discovered mysterious ultraviolet markings on the Venusian clouds.
…..”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.
What is the origin of these ultraviolet markings? What makes their absorption power so high? “…….
http://www.esa.int/esaMI/Venus_Express/SEMFPY808BE_0.html
Is it possible that we don’t quiet yet fully understand how the Venusian climate really works?
…..”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.
@ Finrod
but we still don’t understand it – right!
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.
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
Barry, the simple answer is that the surface temperatures on Venus aren’t caused by the greenhouse effect.
In the fullness of time, you shall be my court jester.
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.
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:
http://www.astro.wisc.edu/~townsend/resource/teaching/diploma/venus-t.gif
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.
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?
@ 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.
http://eprints.lse.ac.uk/27939/1/HartwellPaper_English_version.pdf
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?
The point I (and Hansen) are trying to make here is that the thick atmosphere is a consequence of a runaway greenhouse effect.
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.
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?
@ 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.
Look, is that a shiny bright thing over there…..no it is way too dull…..it looks like an Eclipse Now”
@ Finrod
That would depend on the level of volcanic activity 🙂
http://www.space.com/scienceastronomy/venus-volcano-hotspot-100408.html
That would depend on the level of volcanic activity 🙂
Assume volcanic activity to be that of the long term average.
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.
It would cool.
It would cool.
Really? How much would it cool?
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.
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.
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?
Velikovskyist, I mean.
Ha ha ha! 😉
Well said Finrod! I get the joke.
Mmmmm…. I can’t see where Velikovskyist proposed a theory for Venus’s retrograde rotation. Can you?
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?
Go on Fin, spin me a story 🙂
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/
Go on Fin, spin me a story 🙂
I’m giving you a chance to explain this major logical inconsistency in your position. You’ve got nothing, have you?
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.
@ 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)
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.
Come on Gordon, do share.
(or else we’re back to…)
“Who’s that trotting over my bridge?!” said the troll.
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.
eclipsenow, Gordon, Finrod, can we cut this fruitless back-and-forth off at that point, thanks?
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.
eclipsenow, Gordon, Finrod, can we cut this fruitless back-and-forth off at that point, thanks?
Fruitless? Gordon’s on the ropes, and you want me to stop now?
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).
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.)
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
@ Joel Upchurch
Great link! Thanks for sharing.
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.
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.
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!” 😉
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!
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.
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?
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)
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.
I call revisionist BS Barry. My statement was perfectly clear:
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.)
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:
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).
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.
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?
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.
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.
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.
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..
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.
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?
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)
(Barry’s analogy of course holds true if focussing only on the TSI hitting the planet, but I was looking at it from the perspective of global temperatures on the earth).
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?
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.
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.
If no pejorative was intended, why use terms like “BS” and “climate science has zero credibility”?
Actually eclipsenow, your example makes my point. Read my original comment, I acknowledged the seasonal forcing change 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.
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.
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.
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.
Living in denial: Why sensible people reject the truth
Source:http://www.newscientist.com/article/mg20627606.100-living-in-denial-why-sensible-people-reject-the-truth.html?full=true
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.
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.
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.
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.
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
@greg meyerson – right over his head….
Hey, DV8, I love the way that New Scientist article opens!
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…
Libertarian says:
Except that it’s not 20 times greater, or 350 times greater. See my post here which you completely ignored.
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”.
If you don’t like the National Enquirer then don’t side with the conspiracy theorists by using similar tactics.
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?
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.
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.
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”.
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.
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.
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.
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.
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)
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.)
I regret that I stepped away from your blog and missed this post while the conversation was fresh. I too was reinvigorated by Hanson’s worst case scenario that I laid it out his argument in a diagram here:
http://brightstarswildomar.blogspot.com/2010/01/on-reading-hansons-storms-of-my.html
john
Toonite on ABC1 Voyage to The Planets will hopefully explain how Venus got hot and stayed hot.
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.
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.
[…] 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). […]
[…] There is some (low) probability that feedbacks in the climate system will double the 2100 estimate (or more) — much as I’d like to, I cannot dismiss this possibility. Sea level rise by 2100 will […]