The Leicester press release made it to the Science News section of the U.S. Google News today, and, based on what else was available on the web, it seemed plausible to me. Without your posting helping me through the thinking, I would have wasted brain space etc. on the idea.
just how often do Tunguska scale events occur anyway? I seem to recall that they occur every 100 years or so. And even if they were rarer, and the claimed effect were true, such events would coincide with warmings in even recent records which have nada to so with man and his CO2 and nukes and such.
I put the words in the title into google news, and I only got 1 dupe of the U Leicester report, and one other article , which is claiming the lack of press traction is a case of censorship. physorg, they claim, put it up briefly and then took it down.
It’s too bad physorg didn’t make the old link re-direct to an explanation of how unlikely it is that Tungaska 1908 caused global warming, but such things take time and energy.
The claim that ‘debunkings’ or ‘alternative explanations’ of global warming get censored seems to get an awful lot of traction, despite the seemingly obvious success of many denialist claims. That seems to me to be a more serious problem than one seemingly obscure article claiming Tungaska 1908 caused global warming.
The author of the Tunguska theory, Vladimir Shaidurov, is the winner of the most prestigious scientific award in Russia for 2004, the State Prize, and he is the director of the Computer Modelling Institute of the Russian Academy of Sciences which itself makes the attempts to humiliate him slightly inappropriate.
[Response: This is let through in answer to previous comments. To all commenters, please, no ad-homs or diversions on to non-scientific topics. -gavin]
The “story being censored” claim linked to above is from a secondary source — it’s repeating a claim blogger John Ray found, he says, on Free Republic. I left him the working links in his comment mailbox.
I’m intrigued to see that, following the failure of Russia’s “Academy of Sciences” to contribute to the unprecedented joint report by so many other major national academies prior to the G8 meeting, this kind of third-rate tabloid speculation is now coming out of that country.
This is not in any way to belittle the professional integrity of Russian climate scientists, several of whom I am honoured to call friends, but to wonder at the degree of callous control by politicians.
[gratuitous comment deleted - moderator]
[Response: Minor correction. The Russian Academy of Sciences did sign on to the joint statement. -gavin]
Comment by Lewis Cleverdon — 15 Mar 2006 @ 8:14 PM
Gavin – my apologies, I was misinformed on this.
For the record, and since the meteorite theory claims to make the G8 report wholly redundant, could you possibly list the national academies that did sign ?
Comment by Lewis Cleverdon — 15 Mar 2006 @ 10:19 PM
Every G8 nation and three large developing nations.
Brazil, Canada, China, France, Germany, India, Italy, Japan, Russia, the United Kingdom, and the United States of America
To my mind the third of Gavin’s “three hurdles” has a whiff of begging the question. Imagine a creationist setting up some such hurdle to a Darwinian “… and thirdly, sir, your theory can’t be right as it implies the world was not made in seven days – which is patently absurd”. Moral: You can’t set up “agreement with (Gavin’s idea of) the current consensus” as a precondition for a competing theory! Unless of course you’re a paid up member of the “debate is over” school of climate change. In which case why carry on the discussion?
[Response: The current consensus has arisen because it does the best at explaining the observations and has been shown to have predictive power. New ideas need to do better than that in order to overturn current ideas. Pretty basic stuff really. - gavin]
(Re: response to 12) Perhaps we can agree with the proposition that the winning theory should be the one that “does the best at explaining the observations and has been shown to have predictive power”. Indeed Gavin claims that such a meta-scientific idea is “pretty basic” (if so, one wonders what Karl Popper et. al. found to do all day). Certainly we can tick off the cons (and, who knows, even the pros?) of theory A in contrast to theory B. But I am saying that I don’t think it should count as an additional con against A that, unfortunately, B has got there first and is “true” (whatever our meta-scientific view of that is). That would be begging the question surely.
[Response: No theories in earth science are 'true' in an absolute sense - they simply have more or less explanatory power. If theory B has more explanatory power than theory A it will be preferred regardless of which one got there first. Even if theory A is only a slight modification of theory B, it still has to explain more than it adds in complexity. In this case, theory A 'Tunguska' has very little explanatory power, and in many ways is inconsistent with observations that theory B (the 'consensus') explains quite handily. Even Popper would then reject theory A in such a case. -gavin]
No wonder action on reducing CO2 levels from human activities is very slow in coming. Why do Universities press release this stuff before it has been peer reviewed. Surely Peer review should decide before something is considered worthy of being published in respected scientific journals and hence seen as the truth by the public, the press and Governments around the world.
Something is wrong here surely when junk science once again is allowed to grab headline just because it sounds good and makes for a dramatic effect.
I know this is bit off topic but it is a genuine query. When GISS (or CRU) are calculating the monthly global temperature anomalies which stations do they use from South America. Presumably to qualify for the GISS record they would need to have a complete (or near) record for the 1951-1980 period (1961-90 for CRU) and one which runs up to the present day.
If you have a list I can reference I would be most grateful. It’s just that I’m struggling to find even one that fits the required criteria.
First my reaction to such “not human sources” stories (since I’m not a climate scientist) is — even if that meteor were to have some impact on GW, we still have our GHGs that we are currently emitting. We can’t control meteors (unless we do some DEEP IMPACT thing), but we can reduce our GHGs, so lets get to it. We have to do what we can & reduce even more in the face of such uncontollable threats….which brings me back to:
RUNAWAY GW (as usual)
I read today that GW had reach a 2nd tipping point (see link), that the earth will continue to warm even if we completely stop emitting GHGs — and that we’ve already reached that point (I think this is not news, that we have 2 degrees in the pipes, but I didn’t read the sci jnl article mentioned in this news story): http://www.climateark.org/articles/reader.asp?linkid=53930
I’m thinking of a 3rd tipping point. Okay, there’s more warming in the pipes from what we’ve already emitted, and nature is also net responding to that warming by giving off more GHGs. A 3rd tipping point would be when really serious positive feedbacks start kicking in — like deeper & deeper melting permafrost releasing bigger pockets of methane, and melting ocean clathrates.
In other words, it could get worse, so we have to really really redouble our efforts to reduce GHGs. And with the additional future possibilities of those pesky meteors, volcanoes, increased solar radiation (& for heaven’s sake, let’s stop nuclear testing) — well, we’ve got to reduce our fossil fuel consumption by at least 90% just to offset those. Luckily Amory Lovins says we can do that. So let’s get to it.
Comment by Lynn Vincentnathan — 16 Mar 2006 @ 9:49 AM
Pali Gap -
there would appear to be a further requirement for theory A-Tungusta to gain credence over theory B-AGW, which is that theory A must also describe the mechanisms by which it prevents the demonstrable warming effects of recorded anthro-GHG outputs from causing the observed global warming.
Comment by Lewis Cleverdon — 16 Mar 2006 @ 10:40 AM
While I agree, the theory of the Tunguska Event is far-fetched, I was under the impression that some kind of change has occurred in the mesosphere (thereby causing the noctilucent clouds) and that the exact mechanism creating them (dust, C02, methane, whatever), is still under investigation. My point is only to ask a question, not to refute AGW: Are we SURE that the changes to the mesosphere are DUE to Greenhouse Gasses?
Isn’t (hasn’t) NASA planning to send a satellite to investigate this anomaly (the Aeronomy of Ice in the Mesosphere satellite, or AIM for short)?
Perhaps the usual advice to fledgeling physicians is relevant here. “When you hear hooves, think first horses before you think zerbras.” It is certainly possible that there are zebras around affecting one or another aspect of climate, but greenhouse gases are rather obvious horses. The sceptic argument in these cases seems to be that I can explain observed warming by some rather obscure cosmic ray effect or meteor collision effect, so greenhouse gases must after all have had nothing to do with the matter. Such an argument by itself is insufficient. It must also be explained why greenhouse gas increases, the most obvious cause, have little or no effect. Either that, or the proposed obscure effect must be supported by overwhelming evidence.
The authors also appear to suggest that temperature is driving GHG concentrations, rather than the other way around:
…Therefore the rise of greenhouse gas concentration is more a consequence of warming but not a main reason.
Hypothesis 2: The above mentioned variant of self-stimulated process (with a permanent rise of average absolute humidity, and resulting concentration of carbon dioxide and other greenhouse gases) was launched in 1908 after the atmosphere reconstruction due to the Tungus meteorite. …
That’s hard to reconcile with the data, at least for CO2.
[Response: Excellent point. Anyone claiming that "the rise of greenhouse gas concentration is more a consequence of warming" must be very unfamiliar with the basic evidence. It is beyond reasonable doubt that the current rise in CO2 is anthropogenic - we have summarised the evidence here. Not only do we know how much CO2 we emitted (more than is now left in the atmosphere - which means that the natural reservoirs have taken up part of our CO2 emissions, rather than having released CO2 in response to a climate change). That the increasing amounts of CO2 in the atmosphere come from fossil fuels was already demonstrated by isotope analysis in the 1950s. CO2 increases not only in the atmosphere but also in the global oceans - this is documented by 10,000 measurements - and very likely in the biosphere. And it would be difficult to argue that through a natural climate change, CO2 has suddenly increased to values about 30% higher than at any previous time for the past 650,000 years, and that this occurred by chance just at the same time as humans released more than enough CO2 to explain the rise. -Stefan]
[Response: Sometimes it seems like people are desperate to find something, anything, other than GHGs to be responsible for GW. Maybe they should all get together and have their own mini-IPCC and see if they could get their story straight - William]
The article exaggerates the man’s statement — he’s just saying that variation in cosmic rays can affect cloud formation. Nothing outrageous there.
[Response:Indeed one should not judge what people said just on the basis of newspaper reports. But in this case, Veizer's own writing goes even further than the newspaper report - see our analysis of his key arguments here. -Stefan]
All the natural forcings can change the Earth’s climate — looking at the record as it’s teased out by researchers, there’s a huge number of different things that seem to affect climate at one time or another.
It seems clear that when something like a change in the sun warms up the Earth, or the Earth’s orbital changes warm it up, that’s followed by an increase in carbon dioxide released.
Simply increasing carbon dioxide levels — by hitting the planet with a large rock and causing a massive dieoff, or exposing something like the US western deserts’ coal beds long ago and having them catch fire and burn off — also causes warming. The physics of atmospheric CO2 and warming seems inarguable — no one anywhere is claiming that Arrhenius was way wrong about the physics, right?
The desperation seems to be to find any way to claim that producing a huge pulse of carbon dioxide from fossil sources can’t be all that big a problem — but nobody who does math seems able to defend that argument, it’s just political handwaving claiming the little effects of other things must somehow be greater than the big effect we know is due to human activity, because, well, because they must, because they profit us.
That’s why economics isn’t a dismal science, it’s a happy-face science — because it’s always possible to put costs off the budget (externalize them) and show a profit on paper.
But as to the various identified causes of warming:
Shaidurov is interested in the surface temperature trend decrease just prior to 1906 that is followed by a steady increase to about 1940 (and offers Tungusta). Then he notes the oscillating period from 1945 to 1976 before another steady increase starts again (I think he believes nuclear tests dampened down the Tungusta effect). Is there an AGW alternative explanation for the features on the graph that catch Shaidurov’s eye?
It’s not an either-or question. Theorists need to put numbers on their contributions, to make them possible for scientists to think about!
The sum total of all the different things that are happening — known and unknown — results in the changes (including changes we don’t yet know about — like what’s happening to temperature and dissolved CO2 in the deep ocean over recent time — we don’t have good data yet on that huge volume).
Shaidurov needs to come up with numbers people can do math with, to get his idea into the large group that are included in models and weigh this possibility along with others — correlation is not causation, they tell me.
Hank – that sounds right! “correlation is not causation, they tell me“. Yet isn’t that pertinent to this link of Gavin’s?
I’m interested in this comment by Gavin – “current theories based on greenhouse gas increases …do a pretty good job of explaining the temperature changes over the 20th Century“. Also the comments by Lewis and Leonard setting conditions on competing conjectures. Is it fair to say that Shaidurov is attempting to explain something (in a challenging and bold way) that is possibly an anomaly for the accepted AGW consensus?
Re #21: It is also somewhat deceiving of Canada’s National Post to present this as some sort of new hypothesis. In fact, Veizer’s work has been out there for a few years now…and long enough to be pretty much debunked (at least as an explanation of the current warming): http://www.bbsr.edu/Press_and_Pubs/pr2004/prjan2904/prjan2904.html
Shaidurov is interested in the surface temperature trend decrease just prior to 1906 that is followed by a steady increase to about 1940 (and offers Tungusta). Then he notes the oscillating period from 1945 to 1976 before another steady increase starts again (I think he believes nuclear tests dampened down the Tungusta effect). Is there an AGW alternative explanation for the features on the graph that catch Shaidurov’s eye?
What follows are the best guesses of this non-climatologist. (Corrections appreciated!)
The steady increase to 1940 is partly due to increases in human-emitted greenhouse gasses, but also partly due to increases in solar radiation. The fluctuations between 1945 to 1975 are due to mostly human-emitted sulphates blocking sunlight (thus counteracting the still-rising GHGS), and also due to fluctuations in solar radiation. Post 1975, human-emitted GHGs rise so fast they overwhelm all else.
See this graph (and then hit the ‘back to text’ link at the bottom for context). It graphs the forcings which have acted as heating or cooling forces on our climate. Note the graphs do not all have the same scale on the left side; solar, which has the least variation since 1750, ranges from maybe -0.37 Wm^2 (depending on reconstruction), to +0.35 Wm^2 . Well-Mixed Greenhouse-Gasses (WMGG) starts at 0 and ranges up to almost 2.5 Wm^2. Also, the 0 axis on each graph is relative to an appropriate historical average, not absolute. Compare to the Gisstemp or CRU temp graphs. The steady temp increase to about 1940 matches up well with the rise in the solar radiation shown graph 6.8 (d), and also with the similar-sized rise in WMGGs, shown in graph 6.8 (a). I believe that explains said rise (and also the many reports of warm temps in the 1930s).
From 1945 on, notice the solar radiation fluctuates rather than rising. WMGGs continue to rise. Now look at graph 6.8 (b), look at the sulphates line. Starting at about 1945 is a strong increase in the cooling effect of sulphates (negative numbers on the graphs indicate cooling effect). The increasingly negative sulphate forcing counteracts the rising WMGGs, and then some, resulting in weak cooling from 1945 to about 1975 . Past 1975, rising WMGGs nearly overwhelm all else.
One feature you refer to, which I haven’t explained, is the cooling which ends in about 1906 or so. 6.8 (c), the solar radiation graph, seems to show a weak decrease in solar forcing from about 1898 to about 1906. That may be the explanation.
A similar graph, which sorts the forcings differently, is here.
Please note that above, I intend to speak only of forcings resulting from various factors, not raw amounts, although my phrasing is admittedly ambiguous. Also, forcings are enhanced by positive feedbacks (like water vapor), dampened by negative feedbacks. and modulated by natural cycles of various lengths.
Finally, a realclimate decade-by-decade re-hash of the effect of various forcings on the climate, from about 1880 to the present, would be much appreciated. :-)
Shaidurov won! He wrote exactly: “The purpose of this report is to open the debate and to encourage discussion among scientists.” Scientists are discussing. Shaidurov achieved his purpose, at least, partially. Most of the statements of his opponents are of the type “we know the truth.” My congratulations! I am not an expert, but have PhD in Data Mining. The only question I would like to ask you is: is your climate model the result of fitting? How many parameters did you find by fitting? Is there a small place for doubt? (This is, of course, one question.)
[Response: Let's not mince words here. There is not anything of scientific interest to discuss in Shaidurov's paper. The errors he made in his argument were very elementary. He completely failed to understand the time scales involved in the atmospheric hydrological cycle, or the processes governing atmospheric water vapor. He also blundered by failing to realize that the mesosphere has so little
mass that it is very optically thin, so that mesospheric water vapor has an essentially negligible effect on climate. He failed to understand that there is abundant independent evidence that CO2 increase is due to human activities, and cannot be regarded as a consequence of warming. There is a bizarre claim about the pressure dependence of the freezing point of water at low pressures, for which the only support given is a reference to the general home page of the University of Waterloo science departments. The discussion in the paper (which I just wasted about 20 minutes reading) is full of other elementary misconceptions about the physics of climate, and for that matter, about basic physics as well. The interesting thing about the affair doesn't reside in any scientific issues raised. The two questions are these: How could somebody like Shaidurov with a basically sound scientific training fall prey to so many elementary errors when a brief consultation with a basic text, the most cursory discussion with a colleague who knows the subject, or even with a reasonably well-educated undergraduate, would have made the fallacies evident? How could a reasonably respectable University like Leicester issue a press release involving such a supposedly revolutionary result without screening it with an independent party who knew the subject? Among the many egregious faults of the press release is its misquote of Dessler's book; the quote seems to imply that water vapor changes are not incorporated in models (something also implied in Shaidurov's manuscript), and that human activities can't change water vapor. Dessler, of course, says nothing of the sort. As all regular RC readers know, anything that warms the climate (e.g. CO2) has an indirect effect on water vapor, through the water vapor feedback. Peer review will weed out Shaidurov's not even half-baked idea before it gets much farther, but what surprises me is that Leicester's public relations department was so sloppy. --raypierre]
Comment by Zhenya Gorbachev — 16 Mar 2006 @ 6:03 PM
Bayesian reasoners always attach probabilities to hypotheses and often to data. Hypotheses are compared by the probability that they explain the data. The hypothesis which best explains the data is that supported by the weight of the evidence. Here are some of the details: Given data D, treated as certain for simplicity, suppose there are two competing hypotheses, H and K, to be compared. Determine the probability of the data D given H, p(D | H). The same for K, p(D | K). Now compute
10 log( p(D | H)/p(D | K) ), decibans.
If this exceeds 1 deciban, the weight of the evidence supports hypothesis H. If less than 1/2 deciban, the weight of the evidence is inconclusive.
So for the baysian there is always room for doubt. The chosen hypothesis is simply the best (so far). We all do, in an intuitive manner, what I have described above, say some bayesians. From the original posting by Gavin and the subsequent discussion in the comments, my reading is that the weight of the evidence strongly favors the standard GHG theory over the Tunguska theory, by an estimate of many, many decibans.
Comment by David B. Benson — 16 Mar 2006 @ 6:35 PM
Zhenya, see this glossary of model types from the Hadley centre. To put it another way, modern climate models are simulations of physics – thermodynamics, fluid dynamics, some chemistry, and in some cases a little simulated biology. They are not the result of a ‘fitting’.
There is also a theory that the real cause of global warming is extraterrestrial beings who have for over a century systematically manipulated the development of human technology to ensure that its waste products would alter the composition of the Earth’s atmosphere, e.g. increasing the levels of CO2 and methane, to make it more hospitable to their alien biology, in preparation for a large scale invasion. The paper under discussion here has got it right, except that the Tungaska 1908 event was not caused by a “meteor” but by an alien weapon that was exploded to “jump start” the process of transforming the Earth’s atmosphere. This has been known since documents describing the extraterrestrials’ plan were recovered following the crash of an alien spacecraft near Roswell, New Mexico in 1947, however this theory is being censored by a worldwide conspiracy of climate scientists to cover up the existence of the extraterrestrials. I have to go now; the men in black are at the door.
I apologize so much, but you (and your link) did not answer my question at all. You write, for example, “some chemistry.” It is nice, but where your take the kinetic constants, for example? From the first principles? I don’t trust. It in not a detailed model. There is a hierarchy of fitting, and you change your model after any significant event. Please ask any chemical engineer (real engineer, not a “paper” one) about models of a catalytic reactor “from the first principles.” We cannot produce a model for so simple device without fitting, and you SERIOUSLY tell me about your simulation that is “not the result of fitting.” Let us be modest, please. (And about simulation biology, again, is is even more vague. It gives nice qualitative picture, helps us to understand reality, but ability of quantitative prediction… Let us be modest, please.)
Comment by Zhenya Gorbachev — 16 Mar 2006 @ 7:04 PM
“CO2 has suddenly increased to values about 30% higher than at any previous time for the past 650,000 years, and that this occurred by chance just at the same time as humans released more than enough CO2 to explain the rise”
misses one possibility.
The nuance he misses is that we started using fossil combustion because other resource limits, related to climate and population, limited our choices.
For example, if the receding ice no longer offered enough land for a growing population, then we would have to resort to higher efficiency conversion to extract more productivity. England was hit hard by the little ice age and the depleting forests, they adapted to coal and the industrial revolution was born.
Was this pattern local? Yes, but it gets duplicated. The rise of oil combustion in the U.S. concided with the completion of our expansion west.
So, the question that I always ask is. If we had kept our population limited and used available surface energy, then when would the real ice age start? The Vostok co2 measuremns seems to show that a rise on co2 was well under way by 8,000 bp, and had reached nearly ice age levels by 1930.
Perfectly! Your “decibans” are very good, thank you, I really enjoy.
The only thing, finally, just now I read the Shaidurov paper (not only the abstract and this PR). It seems unbelievable, after all our discussion, but he did not object the GHG arguments. He just told: Look, so perfect piecewise-linear trend. And where are the break points? This mysterious Tunguska Event is at the first? Strange… Let us discuss. This coincidence may be not by chance. There were many atmospheric anomalies fixed after this event… and so on. As I understand, he is absolutely not sure in his explanations, did not call them explanations or theories, just a hypothesis.
Have a nice day, I should leave (a train, sorry).
Comment by Zhenya Gorbachev — 16 Mar 2006 @ 7:24 PM
Zhenya, here are some RealClimate articles I should’ve linked in my earlier post: Modeller vs. modeller and Chaos and Climate which I found helpful, especially the former. Unfortunately, they are not exactly what you are looking for.
Note, at one point you refer to ‘your simulation’. I don’t have a simulation – as I have explained in previous posts, I am not a climatologist. My reply was simplified in part because your post was vague, and in part because my knowledge of climate models is limited. What you meant by ‘fitting’ was not at all clear. In many past discussions I have had, various people (not you) have used ‘fitting’ to mean a pure statistical fit. I assumed – unjustly, it now seems – that by ‘fitting’ you meant a pure statistical fit. When I said ‘They are not the result of a fitting’, I should have said: ‘They are not the result of a pure statisical fit’. Pardon my oversimplification! Unfortunately, I have niether the time nor the understanding to give a complete explanation of the relationship between models and statistics. I don’t even have any good links. :-(
Hopefully Gavin will speak up; he’s done climate modeling, with the GISS GCM .
Pali –25 –I don’t think so, no. Read the response Llewelly posted in 27, he points to the method for figuring out how much effect a given process has, and adding them up. There are a lot of things going on. Tunguska happened to hit at a particular date, but one about the size that made Tunguska comes along every 100 to 300 years or so, on average. Not all that big a deal compared to the strength of other forces, unless someone can come up with a mechanism. That’s the difference here — coincidence is “at the same time” but doesn’t imply any causation.
Now, CO2 and warming, there’s good physics and math explaining how changing CO2 levels causes Earth to retain heat, and it’s not new either.
To nail down whether something like Tunguska can make a big difference, you’d want to come up with estimates for the corresponding numbers for how much dust the meteor left at what altitudes, what the chemistry was that would affect the high clouds, how the nuclear tests would have affected them, and what the result would be. Sum that with all the other known forces acting on climate (some plus, some minus).
Note that the USSR did a very large number of high altitude nuclear bomb tests in the far north. Someone ought to come up with a mechanism for how those changed the climate, if we’re going to take those into account.
Nice idea, nice coincidence, now someone needs a physical mechanism that would explain causation and some numbers to calculate the likelihood.
There’s no big unexplained problem that this new notion would satisfactorily explain — it’s simply another possible idea to which support will or won’t be discovered.
Note he has stated assumptions for the altitude, the mass and the composition of the meteor, for example. Those are assumptions. Compare those to other people’s estimates of how high it exploded, into what sort of material — you can come up with a wide range of possibilities (“error bars” around an estimate). What difference would it make if the assumptions differed? We have no idea ’til he comes up with a mechanism and some numbers. Hope he does. But I suspect this is a ‘talking point’ article not one that’s going to show up in a refereed science journal.
Just my hunch. Look at those links in 27, they ought to answer your question.
[Response: It's not a "nice idea," and it's not even a "talking point" article. There is no data analysis in the paper other than the author's rambling on about the the shape of the well-known graph of instrumental temperature records. The physics behind the supposed mechanism is ill-informed (at best). It doesn't have a prayer of a chance of being right. Any attempt to follow up this idea more scientifically would just be a waste of time. --raypierre.]
Eyeballing Shaidurov’s graph, it strikes me how small the oscillations he describes are. That brief episode strikes me as well within natural variability and error bounds; I’d be OK with calling it a wiggle, but to see “oscillatory behavior” takes a leap of faith. Humans are good at pattern recognition, but also good at spurious pattern recognition.
The difference between the model fit Gavin linked and Shaidurov’s verbal explanation of the temperature trajectory is that the former represents output of a model that embodies a physical explanation of the phenomenon and integrates as much information (e.g. other forcings) as possible. Assuming it also passes basic tests like robustness in extreme conditions, one could start to have some confidence that the fit is more than coincidental. Shaidurov has a long way to go to reach that level – but then he did say “The purpose of this report is to open the debate and to encourage discussion among scientists.”
Pali, here’s another good example of why it’s important to check the actual math before relying on pictures. Pictures have to have some math behind them if they’re telling us anything. As Ronald Reagan memorably said: “Trust, but verify.”
“Analysis of a number of published graphs that have played a major role in these debates and that have been claimed to support solar hypotheses [Laut,2003; Damon and Peristykh, 1999, 2004] shows that the apparent strong correlations displayed on these graphs have been obtained by incorrect handling of the physical data.The graphs are still widely referred to in the literature,and their misleading character has not yet been generally recognized. Readers are cautioned against drawing any conclusions, based upon these graphs ….”
Here’s another peculiar thing about the press release. The press release claims that the work is under consideration for publication in the journal Science First Hand. However, a search on Google and on a number of University library catalogs doesn’t reveal any trace of a journal by this name. The closest thing I found on Google was a newsletter about an NSF-sponsored program to help Middle-School students with science projects (goodness I hope Shaidurov’s project wasn’t one of those!)
So, has anybody located a journal called Science First Hand?
[Response: Thanks for that information. Google finds it if you search "sciencefirsthand", but not if you put spaces between the words, which is what I was doing. If this is indeed the journal in question, it appears to be a popular science magazine rather than a professional journal. That means that the idea isn't even being submitted to peer review in the usual sense. --raypierre]
Tunguska, estimated at somewhere in the range of 12 to 15 megatons and exploding somewhere around 5000 to 8000 meters elevation, would show as a new dot on this chart — a bit higher, and not the largest of the explosions charted here: http://www.johnstonsarchive.net/nuclear/tests/hob.gif
I got curious about what in the world Shaidurov might have meant by his mesospheric freezing point graph. Just as an exercise, by playing around with Clausius Clapeyron (once I looked up the conversion factor from mm Mercury — the units used by Shaidurov — to Pascals) I figured he was actually trying to talk about the saturation vapor pressure, not the freezing point. If this is what he meant, he seems to have confused partial pressure of water with total atmospheric pressure. Even correcting for this, the graph only shows what is standard knowledge in mesospheric thermodynamics — the mesosphere rarely gets cold enough to make water clouds. Shaidurov seems to be trying to argue that since water doesn’t condense easily in the mesosphere, it can stay around for a long time. His argument falls apart, though, because the partial pressure of water vapor in the mesosphere is so low that it has almost no effect on the radiation budget. Hence, it wouldn’t even make any difference if Tunguska could affect the mesospheric water vapor content on the centennial time scale. (Not that Shaidurov has supported such a long residence time for mesospheric water vapor either.)
“In an additional twist, it is suggested that atmospheric nuclear tests from 1940s to the 1970s masked out the effects of the impact due to the supposed mixing up of tropospheric water vapour into the stratosphere after every explosion. This is even odder since stratospheric water vapour is actually quite a significant greenhouse gas, and had this occured to any large extent, it would have been a warming factor, not a cooling one.”
Does this mean that the hypothesis of nuclear winter does not survive testing by modern climate models?
[Response: Nuclear winter is not supposed to have been caused by water vapor, but rather by soot injected into the upper atmosphere from secondary fires caused by nuclear war. It's certainly true that a high soot layer distributed globally would shut off the hydrological cycle and tropospheric convection, and cause the surface temperature to go down to -20C or so for however long it took the soot to settle out of the atmosphere. Where nuclear winter petered out, as a major threat was in the question of how global the soot distribution would be, and how much soot would be injected by firestorms, vs how much would be rained out locally. With realistic assumptions about soot injection, it doesn't seem that nuclear winter significantly alters the already grim calculus of nuclear warfare. It's a moderate additional stress on society, but basically not such a big deal in comparison to the enormous direct impacts of blast and long-lived radioactive fallout. By the way, the story of nuclear winter provides an excellent example of how good science is at weeding out "alarmist" predictions that aren't supported by science. In this case, liberals and pacifists had every reason to believe in the validity of the nuclear winter theory, as it provided additional arguments against strategic doctrine based on pre-emptive nuclear strikes. Nonetheless, the scientific community evaluated the idea very fairly, and in the end came to the conclusion that the initial predictions of nuclear winter did not hold up against more detailed examination. This contrasts with the situation of global warming, in which scientists have become more alarmed the more they have studied the problem. --raypierre]
Maybe Realclimate team has already begun writing about that.
“…Jan Veizer says high-energy rays from distant parts of space are smashing into our atmosphere in ways that make our planet go through warm and cool cycles..”
Not an easy situation this one about understanding Global Warming precise culprits, when everyday there are new hypotheses about this most important situation.
Re, grundt, 46:
Veizer’s claims have already been analyzed here, and rejected. I can’t tell from the various popular news reports whether or not he’s added anything new that would affect the previously linked realclimate analysis. Regardless, the modern climate record contains very little variability that is not confidently explained by the forces outlined in articles like this . Several RealClimate articles spend at least a few paragraphs on this; see here, and here. Also, see my earlier post, if you’ll accept the arguments of this non-climatologist.
Re#47. Thank you, you are absolutely right. Sorry I have not had the conditions nor time to read all the articles and previous posts.
Of course I accept all arguments form people who are reasonable and cautious. No matter if they are or not climatologists. I am not.
Almost everything is important. For example, sometimes some chemical reactions cannot be reproduced because the initial obtained had a few molecules which acted as never recognized catalysts (unnoticed “dirt”).
I am sorry to comment things that have been already well discussed, because I also do not like when people makes comments over and over again about well discussed points. (example you point, 188.8.131.52 Cosmic rays and clouds, from http://www.grida.no/climate/ipcc_tar/wg1/212.htm )
I wanted to express it is overwhelming to deal with so many interpretations. I am aware too many variables are involved, and believe we are in a chaotic system. And, of course, it will never reach steady state. I can be always wrong.
Hi grundt. Good to see your comments again & hope you are doing well. llewelly covered it aptly, but I like the link I provided in 28 above, as it is an interesting discussion that more should read. :o)
Yes, yours is a good link. Mein Deutsch ist nicht gut.
But at least I can read the English links and translate some German text with help.
I have to take time to read it well. The cosmic rays subject was in the past (and is still now) very interesting to me.
Some physical and chemical reactions take place all the time due to these rays. Some reactors must be highly shielded due to their penetration . Very sensitive chemical reactions in labs are thought to have been influenced every now and then by them, leaving scientists without an easy explanation.
The last years events in my life made me lose so much information..
No ad hom, intended , but it may be ad rem that the Moscow Institute is the one ill famed for ‘corroborating ‘ bad models by simply rerunning them on older mainframes.Before it went into Lukoil’s service ,its former Director Gerasimov was guardian of the party line on ‘nuclear winter’.
Lest we forget, his unenthusiastic protege Vladimir Alexandov , was hustled off into oblivion in March ’85 .
The Tunguska analogy is pretty funny, and there is certainly plenty of comedy of manners in the climate wars , but I think we can agree that liquidating modelers goes beyond the limits of tasteful precedent.
What is one to make of a recent press release and submitted preprint blaming global warming on the Tunguska meteor event in 1908?
If global warming were less politics and more science, what you would make of it is an interesting hypothesis which should be looked into, not a crackpot idea which should be ignored and yes, not allowed to be published for fear of causing confusion.
Naturally, the idea will be dimissed as unlikely without much thought. But, they laughed when it was suggested gastric ulcers were due to an infection.
[Response: Not all ideas are created equal. -gavin]
Re #44 — it’s dangerous to go up against Ray on a climate issue, especially for someone like me who has no formal training in climatology. But I do want to say that I still think Nuclear Winter might be a real threat. Turco et al. reexamined the issue in their 1991 paper, and concluded that there were serious flaws in the ’84 and ’86 counter-papers (by Schneider and Thompson, if I remember correctly) — e.g. a plume height off by a factor of three.
[Response: Not so dangerous, I hope! To clarify, I didn't mean to say it wasn't a threat -- just that the immediate and more established consequences of nuclear war are a greater and more clear threat, so that nuclear winter doesn't change the calculus of terror as much as was thought, On the other hand, nobody expected the ozone hole until it happened, so it must be admitted that there are surprises in the climate system that are hard to anticipate. I certainly hope we'll never get to test the nuclear winter theory. --raypierre]
Re #52: It is not for political reasons but for valid scientific reasons that peer-review has come into being. In fact, allowing an article to be published in a scientific journal when it contains serious elementary errors is a more political response than subjecting it to the same standards of peer-review that other articles must undergo. It sounds like you are in favor of what some on the Right might term “affirmative action” for articles that go against the consensus views on climate change. (And really, this would be “affirmative action” in a caricatured sense since this is the kind of thing that has been ruled unconstitutional when applied in the sociopolitical realm…i.e., “affirmative action” in hiring or admission to colleges does not compel [or even allow] one to admit clearly unqualified people just because they are an underrepresented minority).
According to the press release, the theory was “revealed at a meeting at the University of Leicester (UK) and is being considered for publication in the journal ‘Science First Hand’.”
Buried at the end of the article it then states that the author of the theory “visited University of Leicester in April 2005.”
So the press release is based on a talk that took place 11 months ago. And I’ve never heard of Science First Hand. That’s…that’s pretty embarrassing for the university press office to put out this kind of release.
It raises questions about professionalism.
[Response: I hadn't heard of the journal either, but it was identified a few comments back. Science First Hand seems to be a popular science journal, something like a Siberian version of Scientific American. I agree wholeheartedly that something must have gone very wrong at the Leicester press office. --raypierre]
“detonated … at approximately 13,000 feet [4 km]… The giant fireball reached from ground-level to about 34,000 feet [10.4 km] …. The mushroom cloud … stretched sixty kilometers into the sky…
“The ground surface of the island has been levelled, swept and licked so that it looks like a skating rink. The same goes for rocks…. their sides and edges are shiny. There is not a trace of unevenness in the groundâ�¦ Everything in this area has been swept clean, scoured, melted and blown away.”… the area of complete destruction had a radius of twenty-five kilometers from ground zero.
See the fireball viewed from the plane that dropped the bomb, here:
I have a question and this is the right place – does anyone know of any research that looks into what effect, if any, several decades of nuclear testing itself could be having on the climate? Seems to me that adding that much energy (equivalent to dozens of Tunguskas) directly to the upper atmosphere and oceans over an extended period of time is bound to do something. It occurred to me after reading this article. And that would explain why there was no spike and drop-off soon after the T.E. itself.
I can’t do the math, but the question you’re asking is the one that was asked in the Russian article that got this thread rolling, so you’ll probably find your best answer in previous postings. The experts don’t seem impressed by the idea; see the “Nuclear Winter” discussion of a few decades ago. Note that for the ‘Tsar Bomba’ I quoted above most of the heat went straight into space.
I think it’s the difference between a flashbulb and a campfire — the campfire will warm you, even though it may not be as bright momentarily.
It is sobering to actually crunch some numbers, which I won’t do but have seen done, and realize how puny we are. For example, the total energy expended in one major hurricane is equivalent to dozens (or more, I can’t recall) of very powerful H-Bombs. So I think all the world’s nuclear tests would not amount to even one busy hurricane season.
There are probably a lot of legitimate questions to be raised against Vladimir Shaidurov’s “Silver Cloud” theory of global warming: but leave Occam’s Razor out of it! This really isn’t a good reason to discard the theory. Shaidurov’s theory may indeed be vulnerable if his understanding of the mesosphere is defective (we know very little about this region, even now), but the theory fulfills Occam’s Razor so well that I’ve actually included it in an essay on Occam’s Razor at http://logictutorial.com/occam.html
which also includes a general discussion of how our simplistic understanding of Occam’s Razor may have delayed any response to global warming and human industrial activity for decades.
I do expect that the “silver cloud” theory is false, if only because most surprising ideas with only a few weeks of provenance turn out to be false; but mere novelty is no reason to rule it out of court! There’s much more on Occam at logic tutorial.com, so I won’t belabor these points here.
The first criticism listed, that the effects would be local, is absurd. The mesosphere is 50km up and effects there would not remain local very long – even the initial pressure wave was detected as far away as Britian at the time, with the instruments then available, and at the surface of the earth. How likely is it that the effect would still be local, nearly a hundred years later?
The second objection isn’t even comprehensible to me as stated – does this suggest that the largely smooth change in global temperature is disconfirming? Or that the interruption in that smootheness is disconfirming, instead? Or that the change should have been faster? Or slower? And just why, given what putative mechanism? I find myself unable to interpret this objection, as written, so I’ll have to wait for clarification.
Re another objection: comparable very high altitude nuclear tests have never been conducted. As I say in the Occam article, that may be just as well, to say the least.
It is very surprising to me, even shocking, how little media attention this theory has gotten. Doubtless the murder of a minister this week is a more critical issue for our times.
I’m for any story that helps keep our attention on global warming, and the reality of that peril, because I’m convinced by the science that it’s a profound problem. Anything that gets more people to look at the actual graphs of earth’s temperature data over the last century is fine by me.
Russell — When you looked up the altitudes and magnitudes for high elevation nuclear tests, and compared those to the Tunguska elevation and magnitude estimates — What numbers did you find? Where did you find them? Please give us your source.
I posted what I found with references above. Your say you have found different information. Where did you find the numbers you rely on, please?
Promise of a series of articles in Nature and other journals based on one well documented event in 2005, http://www.sandia.gov/news-center/news-releases/2005/physics-astron/lidar.html
mentioned as a challenge to the climate modelers to incorporate dust deposited in the stratosphere. Although I imagine if it’s deposited on a longterm average basis it’s just background, unlike a major volcanic explosion.
Um, one thing the above article does not explain… if not the Tunguska event, what DID cause the sudden recorded upswing in global temperature that began around 1909 Shaidurov is claiming?
I’m guessing it wan’t the Tunguska event. But the data Shaidurov presented seems to imply that *something* must have changed around then that caused an upswing in global temperatures. His conclusion that it must be Tunguska is a leap.
What someone needs to do is : A) check his data! and B) *if* it turns out to be legit, look for alternate explanations and explore them.
It is his data that needs to be looked into, not his theory as to why that data is what it is. The article above does not mention the data at all. But it’s important. Beacuse *IF* the data is correct and tempertaure was cooling through the 19th century, but suddenly started a slow rise beginning in early 20th century, the cause is likely NOT fossil fuel emmissions. (one would expect the rise to begin sooner in that case)
[Response: Don't over-interpret little wiggles in the graph. Natural variability and the known forcings explains it as well as is needed - William]
“… Between 30 to 50 times a year, scientists say, a fireball comes screaming through Earth’s atmosphere, but chances are you never hear about most of these intruders. Since the late 1970s, military satellites have spotted about 400 such events. So far most of the data have remained classified. Scientists estimate that nine out of 10 fireballs remain out of public and scientific view. …”
I also found mention that high altitude dust trails from meteors appear on LIDAR (laser optical ‘radar’) used to look at high clouds. This makes me wonder if there’s a group of climatologists who have appropriate security clearances who get to work with data from the military/security sources (including also the navy/submarine salinity and current records).
Many decades ago I spent a summer at a marine biology program, and recall that the French, British and US marine biologists had to get together at bars after conferences to compare their sonar information. Each country’s research programs used sonar equipment supplied by their national Navy. Each country’s equipment had cutouts built in so the researchers would not see anything that could compromise national security (submarines, and whatever else they were using). And … duh … each nation’s cutouts were different. So over drinks, the scientists could piece together a complete picture of what was going on in the ocean. That was early in the 1960s, I think, maybe even earlier.
Presumably that’s no longer a workable tactic for today’s scientists around the world. But I hope having at least a few fully informed scientists is part of our policy. Research can be published even when the exact data is secret and details of individual events are obscured — I hope! — and still give climate scientists useful information. If we don’t have such a program in place, we ought to, and have the journals accept papers with different rules when the underlying data collection is from classified sources.
If you’ve heard ’7 meters’, that is how much ice is locked up in Greenland’s ice sheet, and therefor, how much sea rise we’ll see if and when Greenland’s ice sheet melts, which is expected to take anywhere from centuries to millennia.