On certainty: Truth is the Daughter of Time

This comment from Dr. Robert Brown at Duke University is elevated from a comment to a full post for further discussion. Since we have a new paper (Shepherd et al) that is being touted in the media as “certain” using noisy data with no stable baseline, this discussion seems relevant.

rgbatduke says:

So wait, you are saying that fossil fuels do not cause warming, but that if we shift away from them to clean energies, there is a risk of the earth cooling? Uh, could you just think that through and try agan?

No, that’s just some people on the list who are “certain” — with no more grounds than those of the warmists — that the Earth is about to cool. In the long run, of course, they are correct — the current interglacial (the Holocene) is bound to end at some point soon in geological time, but that could be anytime from “starting right now” to “in a thousand years” or even longer. Some are silly enough to fit a sine function to some fragment of data and believe that that has predictive value.

The problem is that nobody knows why the Eocene ended and the Pleistocene (the current ice age) started, and nobody knows exactly where and why the Pliestocene is a modulated series of glaciations followed by brief stretches of interglacial.

There are theories — see e.g. the Milankovitch cycle — but they have no quantitative predictive value and the actual causal mechanism is far from clear. So we do not know what the temperature outside “should” be, with and/or without CO_2. We do know historically that the Little Ice Age that ended around 200 years ago was tied for the coldest century long stretch of the entire Holocene — that is, the coldest for the last 11,000 or so years (where it might surprise you to learn that the Holocene Optimum was between 1.5 and 2 C warmer than it is today, without CO_2).

So the fact of the matter is that there is a risk of the Earth cooling — in fact, there is a risk of a return to open glaciation, the start of the next 90,000 year glacial era — but it is not a particularly high risk and we have no way to meaningfully do much better than to say “sometime in the next few centuries”. CO_2 might, actually, help prevent the next glacial era (or at least, might delay it) but even that is not clear — the Ordovician-Silurian ice age began with CO_2 levels of 7000 ppm. That is around 17 times the current level, almost 1% of the atmosphere CO_2 — and persisted for millions of years with CO_2 levels consistently in the ballpark of 4000 ppm. If the Earth’s climate system (which we do not understand, in my opinion, well enough to predict even a single decade out let alone a century) decides it is time for glaciation, I suspect that nothing we can do will have any meaningful effect on the process, just as I don’t think that we have had any profound warming influence on the Earth so far.

The fundamental issue is this. We have some thirty three years of halfway decent climate data — perhaps twice that if you are very generous — which is the blink of an eye in the chaotic climate system that is the Earth. There has been roughly 0.3 C warming over that thirty-three year stretch, or roughly 0.1 C/decade. It is almost certain that some fraction of that warming was completely natural, not due to human causes and we do not know that fraction — a reasonable guess would be to extrapolate the warming rate from the entire post LIA era, which is already close to 0.1 C/decade. It is probably reasonable to assign roughly 0.3 C total warming to Anthropogenic CO_2 — that is everything, not just the last thirty years but from the beginning of time. It might be as much as 0.5C, it might be as little as 0.1C (or even be negative), but the physics suggests a warming on the order of 1.2 C upon a complete doubling of CO_2 if we don’t pretend to more knowledge than we have concerning the nature and signs of the feedbacks.

At the moment there is little reason to think that we are headed towards catastrophe. When the combined membership of the AMA and AGU were surveyed — this is surveying climate scientists in general, not the public or the particular climate scientists that are most vocal on the issue — 15% were not convinced of anthropogenic global warming at all, and over half of them doubted that the warming anthropogenic or not would be catastrophic. It’s the George Mason survey — feel free to look it up. The general consensus was, and remains, that there has definitely and unsurprisingly been warming post LIA, that humans have caused some part of this (how much open to considerable debate as the science is not settled or particularly clear), that there is some chance of it being “catastrophic” warming in the future, a much larger chance that it will not be, and some chance that it will not warm further at all or even cool.

The rational thing to do is to continue to pursue the science, especially the accumulation of a few more decades of halfway decent data, until that science becomes a bit clearer, without betting our prosperity and the prosperity of our children and the calamitous and catastrophic perpetuation of global poverty and untold misery in the present on the relatively small chance of the warming being catastrophic and there being something we can do about it to prevent it from becoming so.

So far, if catastrophe is in the cards, the measures proposed won’t prevent it even according to those that predict it! In fact, it won’t have any effect on the catastrophe at all according to the worst case doom and gloomers. We could stop burning carbon worldwide tomorrow and if the carbon cycle model currently in favor with the CAGW crowd is correct (which I doubt) it would take centuries for the Earth’s CO_2 level to go back to “normal” — whatever that means, given that it varies by almost a factor of 2 completely naturally from glacial era to interglacial. In fact, according to that model the CO_2 levels will continue to go up as long as we contribute any CO_2 at all, because they’ve stuck an absurdly long relaxation time into their basic system of equations (one with very little empirical foundation, again IMO).

Again, I suggest that you reread the top article carefully. I actually do not think it is the best example of Monckton’s writing — a few people have noted that its tone is not terribly elevating, and I have to agree — but I sense and sympathize with his frustration, given the content of the article. There is a stench of hypocrisy that stretches from Al Gore’s globe-hopping by jet and his huge house and large car all the way to a collection of people with nothing better to do who have jetted to Doha to have a big party and figure out how to continue their quest for World Domination, hypocrisy with king-sized blinders that seem quite incapable of permitting the slightest bit of doubt to enter, even when bold predictions like those openly made in the 2008 report come back to bite them in the ass.

I myself am not a believer in CAGW. Nor am I a disbeliever. The only thing that I “believe” in regarding the subject is our own ignorance, combined with a fairly firm belief that there is little reason to panic visible in the climate record, and that is before various thumbs were laid firmly on the scales. Remove those thumbs and there is even less reason to panic.

My own prediction for the climate is this. We will probably continue to experience mild warming for another ten to twenty years — warming on the order of 0.1C per decade. It will probably occur in bursts — the climate record shows clear signs of punctuated equilibrium, a Hurst-Kolmogorov process — most likely associated with strong El Ninos (if we get back to where strong El Ninos occur — the last couple have fizzled out altogether, hence the lack of warming). In the meantime, we will without much additional effort beyond existing research and the obvious profit incentives drop the cost of solar power by a factor of four, and it will become at least competitive with the cheapest ways of generating electrical power. We will also have at least one major breakthrough in energy storage technology. The two together will cause solar to become more profitable than coal independent of subsidy, for much but not all of the world. Without anybody being inconvenienced or “doing” anything beyond pursuing the most profitable course, global consumption of carbon will then drop like a rock no matter what we do in the meantime.

Beyond twenty years I don’t think anybody has a clue as to what the temperature will do. I don’t even have a lot of confidence in my own prediction. It wouldn’t surprise me if it got cooler, especially if the Sun enters a true Maunder-style minimum. Nor would it surprise me if it got warmer than my modest prediction. But either way, I think roughly 500 ppm is likely to be the peak level of CO_2 before it comes down, and it may well fail to make it to 500 ppm, and even the catastrophists would have a hard time making a catastrophe out of that given 0.3 C of warming in association with the bump from 300 to 400.

We could make it more likely to cut off before 500 ppm — invest massively in nuclear power. Nuclear power is actually relatively cheap, so this is a cost-benefit win, if we regulate them carefully for safety and avoid nuclear proliferation (both risks, but less catastrophic than the inflated predictions of the catastrophists). But I don’t think we will, and in the end I don’t think it will matter.

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Joseph Bastardi

will be hard to warm in a cold pdo which is not a nino friendly. In addition warm AMO is about to run its course ( within 10 yrs) would suggest reading Dr Bill Gray ideas on the thermohaline circulation and where we are about to go. He correctly forecasted the flip in the PDO and by 2020, the AMO should turn too. I am forecasting cooling and have been since 06 , back to levels as measured by satellites, of the 70s by 2030. I am in complete agreement with the idea that the more you study the majesty of the planet, you realize how little we are, or have to do with it

tadchem

What we *really* know, empirically, is that we have (1) a tad over 30 years of spotty data, much from less than reliable sources, (2) a handful of computer models that everyone knows have oversimplifications built in at almost every line of code, and (3) indications in the fossil records of rocks, ice, and plants that the climate is variable and has been warmer at some times, and cooler at other times.
What we *really* know, theoretically, is that (1) there are scores of variables that could affect the climate, (2) many of them have interactions with each other that have not yet been characterized, and (3) some are known to be non-linear and even ambivalent depending on their interactions with other variables.
What we *really* know, from experience, is that extrapolations are for fools. Just because variable A went up (or down) X points yesterday does not mean it will do so again today.
Ask Wall Street.

Joe – yes; all this farrago regarding CAGW simply demonstrates the extraordinary hubris of the warmes, to think that we really affect this globe that much.

MikeB

For those true believers who always reinforce their arguments by resorting to an ‘appeal to authority’, you should be aware that the full quotation, from Francis Bacon circa 1600, is
“Truth is the Daughter of Time, not of Authority”

jeanparisot

Dr Brown needs to provide a link to where at Duke I should send money for enlightening me repeatedly. Just the spin off reads of his references teach me things.

son of mulder

The word “chaotic” is used once and once is enough to support the rest of the article.

Julian Flood

Dr Brown writes:
quote
I suspect that nothing we can do will have any meaningful effect on the process, just as I don’t think that we have had any profound warming influence on the Earth so far.
unquote
With all due respect to your greater knowledge, I suspect we could, can and may be so doing. We are spreading enough light oil onto the ocean surface each year to cover it completely approximately every fortnight. I have seen oil smooths snaking out to the horizon from Tenerife, seen a smooth covering tens of thousands of square miles off Portugal, seen the Med covered from end to end. Oil smooths warm the sea surface by reducing albedo, lowering emissivity, reducing mechanical mixing, starving plankton to lower DMS production, reduce aerosol production by breaking waves, lower turbulence and thereby reduce stratocumulus formation and reduce evaporation.
Google Tom Wigley and ‘why the blip?’. Google Benjamin Franklin and Clapham pond.
The north Siberian coast has enough light oil coming down its rivers to equal an Exxon Valdez every five weeks — add in the North Slope and I’ll bet that means the Arctic seas are covered completely. Perhaps that’s why their warming is anomalously high.
Anyway… All you need to do carry on polluting the ocean surface. That’ll do.
JF

beesaman

And that folks is what a real scientist sounds like.
Hansen, Mann et al you might want to take note!

TomRude

@Joe, cooling? Isn’t that always because of global warming? 😉

mpainter

Dr Brown:
“My own prediction for the climate is this. We will probably continue to experience mild warming for another ten to twenty years-”
For the last fifteen years there has been no warming- absolutely none. So why do you say “continue”?

John Blake

Climatologists may not know “why the Pleistocene started” but geophysicists most certainly do. The short answer is plate tectonics, which deployed North and South American landmasses some 2.6-million years ago to wall off Eastern from Western hemispheres, thereby disrupting global atmospheric/ocean circulation patterns.
Since the Cretaceous/Tertiary (K/T) Boundary some 65-milion years ago, Planet Earth has experience five major geological eras lasting 12 – 16+ million years apiece. On this basis, our current Pleistocene Era should persist another 12 – 14 million years, until North and South American continents once more drift apart. During this time, the Earth’s micro-minuscule atmospheric film –say 4 miles on a planetary radius of 4,000 miles– will continue subject to Milankovich cycles, oceanic oscillations, total solar irradiation (TSI), volcanism and so forth, but “climate” is inevitably due for periodic “cold shock” fluctuations for another 14-million years or so.
In its self-induced astro-geological ignorance, “climate science” for all its high-tech gobbley-gook is akin to Blondlot’s N-rays, J.B. Rhine, Immanuel Velikovsky, Trofim Lysenko, and others of that ilk. Entering a 70-year “dead sun” Grand Minimum similar to that of 1645 – 1715, the Green Gang of AGW Catastrophists
is purposefully, willfully, putting all humanity at risk.

Joe Prins

Just finished reading John Kehr’s “the inconvenient skeptic”. I like it because:
1) It takes the very long view, that is, not decades but centuries:
2) It deals with the earth as a chaotic system;
3) It deals with the insolation reaching the earth esp. the Northern Hemisphere and
4) It posits that there is an energy gap of about 14 W/m2 and there has been for about 3000 yrs;
In other words, looking at the energy received by the earth and where makes a lot more sense to me than any Co2 theory. Trying to fit the Co2 theory to the facts is a fools game. Instead use facts to formulate a theory.

And there you have it.
Bravo!

James Evans

I’m printing that out and handing it to some friends.

John West

@Julian Flood
Ever hear of bacteria? Oil is biodegradable.
That’s why the Gulf of Mexico didn’t end up the catastrophe that some predicted. Yes, a lot of oil goes into the oceans both naturally and from human activities; but a lot of oil is consumed by bacteria as well.

Miket

Excellent commentary. I just wish one could persuade the likes of Obama and Cameron to take the time to read such a balanced view of the subject.

John West

And this is what the alarmists never seem to get:
“The fundamental issue is this. We have some thirty three years of halfway decent climate data — perhaps twice that if you are very generous — which is the blink of an eye in the chaotic climate system that is the Earth.” —- RGB@Duke
“There is something fascinating about science. One gets such wholesale returns of conjecture out of such a trifling investment of fact.” —- Mark Twain

Alex

In an October 2011 paper published in the International Journal of Public Opinion Research, researchers from George Mason University analyzed the results of a survey of 489 scientists working in academia, government, and industry. The scientists polled were members of the American Geophysical Union or the American Meteorological Society and listed in the 23rd edition of American Men and Women of Science, a biographical reference work on leading American scientists. Of those surveyed, 97% agreed that that global temperatures have risen over the past century. Moreover, 84% agreed that “human-induced greenhouse warming” is now occurring. Only 5% disagreed with the idea that human activity is a significant cause of global warming.[18][19]
^
from wikipedia is it me or is this something completly different then the Dr is saying about the survey? Perhaps it’s just another case of wikipedia bull we have seen before regarding climate articles.

Gary

Just a couple of corrections are needed in this post:
1. It’s pretty well established that the closing of the Central American isthmus initiated the Pleistocene glaciation cycles by diverting oceanic circulation patterns.
2. The Milankovich theory is quiet well-proven and is quantitatively predictive. Various other influences may affect the timing a bit — such as the lag effect of ice on the continents having to melt away before temperatures increase — but the orbital parameters that control insolation are dominant.

theduke

Dr. Brown is a born teacher and I envy his students.

George Lawso9n

Julian Flood.
What an exagerating alarmist you are. Yes we have all seen oil smooths in the sea from time to time, but I doubt whether anyone would support your stupid statement that you’ve seen oil smooths completely cover the whole of the Mediteranean. I suspect that is part of the warmists scaremongering again. Just look at the sites of major oil spills around the world and see how they have very quickly returned to their natural state within a very short space of time. Even the area of last years BP drilling accident in the Gulf of Mexico, which we know was devaststing to the local fishing industry, has surprised officials at the speed of its recovery to its natural ecology. Yes, the earth is capable of taking in its stride anything which we humans throw at it. It might be major in the warmists eyes, but it is very insignificant as far as mother earth is concerned

Doug Huffman

Here is a graph, a graphic, of the current, as of 3 Dec, monthly Smoothed Sunspot Numbers and of their 2009 consensus predicted numbers.
http://www.swpc.noaa.gov/SolarCycle/sunspot.gif

Duster

Julian Flood says:
December 3, 2012 at 11:32 am

Julian, you need to pay less attention to doom-prophesying “authorities” and more to basic science, in this case geology. The volume of oil seeping from natural sources sources is far greater than human linked “catastrophes.” Studies in the Gulf have imaged steady minor seeps over square miles. The Exxon Valdiz in Alaska and more recent events in the Gulf of Mexico are geographically focused – point locations – that magnify the apparent seriousness of the events. In reality, a small fraction of the oil you would pick up walking on a beach in the Gulf, the beaches of Central Africa, the Arctic, or California, or any of a dozen other places is the result of human activity. Just like water, oil seeps to the surface – la Brea in L.A. for instance, or the asphalt “volcanoes” in the channel off southern California. The asphaltum used prehistorically by the Egyptians, the Chinese, the indians of the southern California deserts, and in many other parts of the world was from natural seeps as well. Tanker spills and plumes from failing wells are are dramatic and can be very hard on wild life, but even there you want to look at the fossil count from la Brea before assuming to much about the influence of humanity on the environment.
Pollution is a serious problem, but we really need to know the magnitude of our own outputs, before we can do something useful about them. It is a profound mistake to simply conclude that nature would be benign if only people were tidier. It is simply not true and makes a secular “original sin” assumption that is logically and empirically unsupported.

BobG

In pointing out that there is no scientific certainty about several things, you then write what I think is a non-scientific opinion, “there is a risk of a return to open glaciation, the start of the next 90,000 year glacial era — but it is not a particularly high risk …”.
I have not seen any paper about this and don’t really think the risk of another ice age is quantified in any scientific way. It is possible that all that is needed is another Little Ice Age of a sufficient magnitude that we hit a “tipping point” after which the earth gradually slide decade after decade inexorably towards an increasingly cold and glaciated earth. Given the current very quiet sun, perhaps such a little ice age is pending. My non-scientific guess is like yours that we probably have a few hundred more years. But it is an opinion and not based on anything quantifiable.

rgbatduke

With all due respect to your greater knowledge, I suspect we could, can and may be so doing. We are spreading enough light oil onto the ocean surface each year to cover it completely approximately every fortnight.
Let’s look at this closely, shall we? And let’s use arithmetic in the form of a “Fermi Estimate”, not words. The surface area of the ocean is 3.6 \times 10^{14} square meters (four hundred trillion square meters). In order to cover with oil at a depth of 1 millimeter one time would require roughly 360 billion metric tons of oil. The complete annual production of oil worldwide is currently around 30 billion barrels of oil, and it takes roughly seven barrels of oil to produce a metric ton. That is, the complete annual production of oil is around 4 billion metric tons. This would make a layer approximately ten microns thick, if you could get it all into the ocean at once.
Of course, we don’t do any such thing. Oil on the ocean is wasted oil, and we want to use it. I would cheerfully estimate that we don’t lose one hundredth of one percent of all the oil mined into the ocean in a year. In that case it would make a layer one nanometer — two or three molecules — thick. Once. Out of a whole year’s oil production, assuming what is in all frankness probably an egregiously high estimate of waste.
On a fortnightly basis divide by 26. We spread a layer one whole molecule thick roughly once ever ten fortnights, call it four months.
This still doesn’t do your assertion full justice. “Oil” is a heterogeneous mixture of hydrocarbons. Some of them are volatile and almost immediately evaporate. Others are dense and sink. All of them are quite tasty to a number of things that live in the ocean. While I am quite certain that there are places where oil slicks both natural and manmade can be seen on the ocean, there is no possible way that those slicks would ever actually cover the ocean because they would be eaten, oxidized, evaporated, and sink faster than they could ever spread. At no time could they cover even a significant fraction of the ocean’s surface area. That, as noted above, is enormous.
So I must regretfully state that unless I have made an egregious error in my arithmetic above — always possible — your statement is an absurd number of orders of magnitude away from being anything like truth. I spend my summers in boats, fishing off of the North Carolina coast outside of its busiest harbor. I have yet to see one oil slick, or even a single extended patch of oil on the surface, even in the harbors. I have also read papers that suggest that the oil dumped into the Gulf in its disaster was eaten at many times the rate anticipated beforehand, so that nature actually cleaned it up at an astounding rate, and that really was a well dumping enormous amounts of oil directly into the ocean (but tiny amounts compared to its surface area for all of that).
I suggest that you change your primary sources away from ones that not only lie to you, but lie to you in a way that insults your intelligence and ability to do arithmetic. I also humbly suggest that if you have posted this misinformation elsewhere, you consider the damage this sort of nonsense does to everybody’s ability to hold a rational conversation on the subject. I would expect the “coverage of the ocean with oil” to be an utterly negligible effect compared to the direct greenhouse effect of the volatiles and natural gas released when oil is pumped plus the greenhouse effect of the burned oil in the form of CO_2. Those positive warming effects might well be partially balanced by particulates that could have either warming or cooling effects and aerosols that are mostly cooling. In other words, there is literally no point even mentioning it, which is why nobody ever does and they are completely ignored in all global climate models.
Try again.
rgb
rgb

DavidG

Wonderful comment at precisely the right time! There is so much unscientific noise masquerading as fact, no wonder most people give up trying to decode it.

rgbatduke

For the last fifteen years there has been no warming- absolutely none. So why do you say “continue”?
Because looking at any fifteen year interval as representative of a trend in climate science is so utterly absurd as to beggar description. On both sides. Frankly, 33 years is little better. I’m extrapolating the rise out of the LIA to have at least a century or three in my baseline, and of course that is arguably not terribly meaningful as well. I’m also hedging my bet with the belief that the GHE actually exists and is unlikely to have actively negative feedback; with CO_2 based GHE only one expects roughly 0.1 C/decade of warming, assuming CO_2 levels continue to rise.
This latter is actually the null hypothesis of the entire discussion! Given ignorance about net feedback, the assumption of zero feedback is the best one can do. Climate scientists believe in their positive feedback models enough to bump this to 0.2 to 0.3 C/decade; I do not. That doesn’t mean that I believe the data suggests negative feedback (reliably) either!
rgb

@mpainter: I don’t want to put words into Dr. Brown’s mouth, but I believe that what he was talking about is rise averaged over a long period – a century or more. The Earth’s temperature doesn’t, and never has (to my knowledge) exhibit monotonic rises (or falls) of temperature unless you look at a long term average.
Looking at the practically instantaneous snapshot that we have of processes which take millenia to run their course is meaningless.

kwik

Dr Brown:
“My own prediction for the climate is this. We will probably continue to experience mild warming for another ten to twenty years-”
mpainter says:
December 3, 2012 at 11:46 am;
For the last fifteen years there has been no warming- absolutely none. So why do you say “continue”?
Yes, why?

I fully agree with Dr Robert Brown about the limits of our present knowledge. To overstate what we know is to create a blind religious belief. Having said that, and as a cycles researcher, I must take issue with the statement “Some are silly enough to fit a sine function to some fragment of data and believe that that has predictive value”. Sometimes the fragments of data are quite long in the form of proxies. But yes, we must take care in interpreting these.
The fact is that people using cyclical methods have the best success at predicting solar changes. The 208 year cycle present in several solar proxies and in the instrumental SSN records clearly indicated that we were due for several weak solar cycles starting with the current one. The climate record also shows this same cycle period so we can expect some cooler period for a while. However that must be superimposed on other longer and shorter cycles. There is a 2300 year climate cycle which is still warming. There is a cycle of 53 to 60 years which also peaked out at then end of the last century.
For these reasons I would expect a slight cooling for then next decade or two before another 30 year warming period. A different guess to Dr Brown.

Walt The Physicist

@ Julian Flood:
The main statement of the post is a humble admission that, very little known about physics of the Earth climate and therefore any reliable prediction is impossible. Unfortunately very few educated people and even fewer scientists admit (or realize) that “science” isn’t omnipotent. Not surprising, since increasingly the “tabloid science” dominates the scene for the reasons of ease of obtaining funding and higher entertainment value. And thus, the “tabloid scientists” entertain/scary public and overwhelm funding sources by showing that their peer-reviewed “science” publications undoubtedly show that “oil smooths warm the sea surface by reducing albedo, lowering emissivity, reducing mechanical mixing… lower turbulence and thereby reduce stratocumulus formation and reduce evaporation.” In the midst of all this confusion neither public nor program managers notice that “reducing albedo” is opposite to “lowering emissivity”… In midst of this confusion examining and questioning the accuracy of these research becomes next to impossible, especially after energized and vocal consumers of “tabloid science” weigh in. Please stop drinking kool-aid, go start business, do something usefull.

DavidG

Not surprising that someone named Flood is prone to exaggeration, given the last month.;]
I do agree that if no warming has occurred, then Dr. Brown needs to reconsider what he wrote about continued warming.including also the facts of a cold PDO and eventually a cold AMO, coming by 2020 as Joe predicts. If it does cool, we will be revisiting the incredibly high cost of carbon mitigation for no scientific reason.

rgbatduke

Just a couple of corrections are needed in this post:
1. It’s pretty well established that the closing of the Central American isthmus initiated the Pleistocene glaciation cycles by diverting oceanic circulation patterns.
2. The Milankovich theory is quiet well-proven and is quantitatively predictive. Various other influences may affect the timing a bit — such as the lag effect of ice on the continents having to melt away before temperatures increase — but the orbital parameters that control insolation are dominant.

I won’t argue with either of these — although I think that I could. Not so much with the hypotheses, but with the degree to which the evidence “proves” them, especially without controlling for other possible factors. For example, I’ve read theories suggesting that the upthrust of the Himalayas exposing large amounts of rock that subsequently weathered and absorbed CO_2 was also a factor, or responsible, depending on whether or not you want CO_2 to be the sole meaningful driver of going in and out of ice ages on a geological time scale. I don’t think that is “proven” either. I think it is really pretty difficult to prove what happened between 50 and 3.5 million years ago to gradually drop temperatures to where orbital variations seemed rather “suddenly” capable of modulating glacial/interglacial cycles. I also think — and several of my climate scientist friends seem to think — that it is difficult to quantitatively predict or understand why the cycles went from 20-26 thousand years (axial precession) to 40 thousand to 100 thousand years, and why the last half million years have been 90 thousand (or so) of glaciation followed by 10 thousand (or so) of interglacial.
Milankovich works qualitatively well, or even semi-quantitatively well in that it gives us a nice heuristic explanation for the primary fourier components in the pliestocene thermal record as determined by proxy, but it is completely useless as a predictive tool capable of telling us what the temperature outside “should” be right now with or without CO_2. It cannot explain the particular date the Wisconsin glaciation started to end. It cannot explain the Younger Dryas. It cannot explain the several deep dips in global temperature visible in the proxy based thermal record of the Holocene (although it may give us some insight into the Holocene Optimum and general slow reduction of temperature that followed ignoring the fluctuations). It cannot explain the MWP or the LIA. It does not explain why the world warmed again after the LIA or was warming on its own at least up to where CO_2 entered the picture as a possible factor.
Without a quantitatively precise theory for the baseline temperature that the Earth should have ignoring human influences, the task of extracting the human “signal” from the unknown multiple-timescale “natural” variation of the climate due to the Milankovich agencies and many other things is, IMO, a bit of a chore if not an actual joke. We haven’t the foggiest idea of what the temperature in the latter half of the 20th century would have done if humans had not existed on the Earth at all, let alone what fraction of the temperature we imperfectly observed with large error bars was due to human affairs.
If you disagree (and have quantitatively precise references that predict the day and the year of the next ice age) please let me know as I’d love to see them. In the meantime I’ll have to assert that the theory is at least as reliable as the Mayan Calendar for predicting the end of the world. Might be even more reliable, dunno. But either way I’d want to see the direct, contemporary evidence and not yet another argument on the basis of numerical correspondence.
rgb

Kev-in-Uk

John Blake says:
December 3, 2012 at 11:47 am
My thoughts exactly, +1
I do think rgb has done a great job of enlightening many folk – and he has obviously managed to grab some geological understanding (i.e. re timescales) along the way – it is truly a shame that climate science does not embrace the same understanding. Geological timescales are logically the only real ‘baseline references’ for climate analysis (any analysis of climate on anything less than a few millenia of data is unable to see the ‘real’ natural climatic variation, cycles, etc) – and even then, they can still change every few million years!

rgbatduke

Of those surveyed, 97% agreed that that global temperatures have risen over the past century. Moreover, 84% agreed that “human-induced greenhouse warming” is now occurring. Only 5% disagreed with the idea that human activity is a significant cause of global warming.[18][19]
The 97% is bullshit — it is a direct read of the thermometric data. The 3% that disagreed must really be mavericks…;-)
If only 84% agree that anthropogenic greenhouse warming is now occurring, 16% disagree, is it not so? That is slightly more than the 15% I asserted. Additionally, IIRC some 53% thought that there was anthropogenic warming, but that it would not be “catastrophic” by the end of the century (although I’m remembering the numbers without looking them up again). Added up, over 2/3 of them disagreed with CAGW., while some 80 to 85% of them believed in some measure of human induced GHE warming.
The 5% can also be ignored, because most of them no doubt know of things like the Sahara desert and desertification due to land use changes. But those things are unlikely to be a major factor in future catastrophic warming. Or maybe not, dunno.
It is still far from the homogeneous 96% of all scientists agree in global warming. Possibly true, but who cares! That’s just reading a thermometer, not assigning causes. The following, however, is a true statements:
According to the George Mason Survey, over 15% of the climate scientists surveyed did not agree with human induced greenhouse warming as a hypothesis.
Not really surprising. In physics, you can’t get everybody to believe in any controversial proposition at the 96% level. Why would it be different in the most difficult physics problem in the world, the solution of the most fiendishly complex set of nonlinear differential equations I can even imagine?
rgb

rgbatduke

The fact is that people using cyclical methods have the best success at predicting solar changes. The 208 year cycle present in several solar proxies and in the instrumental SSN records clearly indicated that we were due for several weak solar cycles starting with the current one. The climate record also shows this same cycle period so we can expect some cooler period for a while. However that must be superimposed on other longer and shorter cycles. There is a 2300 year climate cycle which is still warming. There is a cycle of 53 to 60 years which also peaked out at then end of the last century.
And I believe that people who were born in the sign of Aries are maximally compatible with Libras. And that the length of skirts is a definite predictor for the market. Or (fill in your own favorite example of post hoc ergo propter hoc). I don’t actually completely disagree with you; I just don’t agree that the predictions of a Fourier Transform of a given data set are particularly robust outside of the interval where it is fit. Do I need to go through the reasoning for my doubt?
The discovery of patterns in data is an important first step in understanding the underlying causes of that data. However, humans find fluffy sheep in the clouds because that is the way we are wired, and it is a cruel fact of functional analysis that fitting an arbitrary function with any basis you like can often be done as closely you like in some finite interval and yet the fit have absolutely no extrapolative value whatsoever. Without a physical model to explain why “208 years” is an important number, you might as well be doing astrology. It’s the year of the dragon, that’s always hot. Why not?
rgb

Stephen Richards

BobG says: and everyone else
December 3, 2012 at 12:39 pm
Dr Brown is correct in everything his says. He may not be as precise as he would have wished but he was writing this as a comment and not a post. Although you may have read that the movement of the techtonics plates started the current ice age cycling, and that is not an unreasonable assumption, it has never been proven conclusively. Also, no-one has ever been able to quantify how the Milan. cycles produce an ice age. Up to now, the only quatifying attempt has merely shown that it is likely that another trigger, along with the Milan. cycles, would have been necessary. Lastly, we have in the past on various sceptic blogs, had some lengthy discussions on what could cause the ice age cycling within the general ice age of the past few million years. No-one that I have read has yet found the trigger, definitively. Why did we cycle down to the little ice age? It might has been the MM and maybe we will have some conclusive proof in the next 20 years or so but at this moment there is none. You might say the sun, PDO/AMO, thermalhaline anything you wish but show the proof, please.

Stephen Richards

rgbatduke says:
December 3, 2012 at 1:32 pm
Witness Mannian maths.

Stephen Richards

sorry, I wrote the 2 posts above before Dr Brown’s 2 posts had appeared

mikerossander

Alex, the two descriptions of the George Mason study are consistent. “84% agreed that human-induced greenhouse warming is now occurring” is (within rounding) semantically identical to “15% were NOT convinced of anthropogenic global warming”.
Regarding your second snippet about human activity being a “significant cause” – start with your quote that “97% agreed that that global temperatures have risen over the past century” (regardless of cause). Your quote that “Only 5% disagreed with the idea that human activity is a significant cause of global warming” only means that 95% (all but 9 of the respondents who said that temperatures have risen at all) agree that human activity has contributed to warming enough that the null hypothesis of 0.000000…degrees impact can be rejected. Since the concept of urban heat islands is universally accepted, the conclusion is unsurprising. Heat islands may only add a tiny fraction of a degree to the global temperature but they clearly do exist. No conclusions can be drawn from that statistic about the believed magnitude of the human contribution, however.

Stephen Richards

Unfortunately very few educated people and even fewer scientists admit (or realize) that “science” isn’t omnipotent
That is something of a cruel statement. There are many, many scientist that read and comment here and very well educated ones at that. I was once but have been retired for too long to remember how well.

Very good, Robert.
I describe science as ‘the exploration of uncertainty’. Until you have honesty about what you are uncertain about, there can be no science.

rgbatduke

Why did we cycle down to the little ice age? It might has been the MM and maybe we will have some conclusive proof in the next 20 years or so but at this moment there is none. You might say the sun, PDO/AMO, thermalhaline anything you wish but show the proof, please.
Yes, precisely. Even listening in on the arguments of experts in the field like Lief, I come away unconvinced on almost every topic that is individually debated. There is a proliferation of hypotheses, all of them at least somewhat plausible, none of them either proven or refuted by our absolutely miserable half-century max of instrumental data that didn’t rely on hot electron tubes with their notorious drift to collect and assess, let along our 33 years of mostly-reliable satellite data. The oceans alone — 70% of the Earth’ surface, a huge VOLUME of its thermal reservoir — we have good data on for maybe half of that. And then there is the sun.
If one applies an honest Bayesian analysis to the entire multilple hypotheses descriptions and models of the climate, one concludes what mere common sense (Bayesian analysis as produced by our intuitive brains) already tells you — we haven’t a clue about what drives the climate, not really. Or rather, we have too many clues, not enough data, and cannot home in on what is probably true to the exclusion of what is probably false yet, in nearly any particular. We cannot even reliably account for large century-scale movements that are empirically many times larger than all of the supposed AGW that has occurred to date, let alone for variations on a scale of thousands or tens of thousands or hundreds of thousands or millions of years.
One cannot show the proof in this — it isn’t yet possible to prove anything. In fifty years, maybe. In twenty years, perhaps but don’t hold your breath, In a century, probably. To put it bluntly, temperatures could go back down for twenty years and the CAGW hypothesis could still be correct — we have no idea what kinds of natural drivers might override it in the short run, or what “the short run” even is.
rgb

rgbatduke

No conclusions can be drawn from that statistic about the believed magnitude of the human contribution, however.
No, but the working group reports in the AR process probably give one some idea. Not the politicized summaries — the climate guys I know indirectly from interactions on this and other lists don’t like them any more than ardent “skeptics” do as they are political crap, not summaries of the actual science (which is always far more cautious and full of doubt than the summaries for politicians the lay public ever end up). I truly do think that it is a fair statement that the majority of climate scientists believe in one variant or another of “there is some degree of anthropogenic global warming caused by increases in CO_2, and that the likely warming produced by the end of the century will probably be damaging, but not catastrophic”.
Individually you’ll have a wide range on both sides of this statement — 15% plus who remain uncertain even about the “proven reality” of GHG AGW in the first place, 25% or so who think it will be catastrophic, and people smeared out in between. The latest “consensus” of maybe 2.5C of total warming reflects that range, probably biased somewhat to the warmer side of things, but again, come back in five years with temperatures still stable and ask again and you’ll get a very different answer.
The public doesn’t ever get a measured presentation of this sort of reality — that scientists really do Not Agree on complicated and uncertain science supported by sketchy and incomplete data and somewhat corrupted by a natural desire to “save the world” (only possible if the world is in danger!). It is reduced to sound bites and out and out lies — such as the lie that we cover the ocean with oil ever fortnight (right up their with the arithmetic supporting Noah’s Ark, preserving several million species for most of a year in a floating wooden boat the size of WalMart ventilated through less than a square meter). Or the lie that Sandy was “caused by human produced climate change”.
Horseshit.
And now I really must go, at least for a while.
rgb

xham

Since the article quotes George Mason survey that is not freely available can anyone provide a link to corroborate of the 50+ % who don’t believe in catastrophic AGW? Thanks.

David Schofield

“rgbatduke says:
December 3, 2012 at 12:53 pm
For the last fifteen years there has been no warming- absolutely none. So why do you say “continue”?
Because looking at any fifteen year interval as representative of a trend in climate science is so utterly absurd as to beggar description………….”
Agree with that but when does the agw theory become falsifiable?

wayne

I so much agree with rgb’s statements on the inherent stability of Earth’s climate system.
If you have a question as to part of “why”, check some thoughts in this thread:
http://beforeitsnews.com/science-and-technology/2012/11/wayne-jackson-new-identity-linking-meteorological-phenomena-2498686.html

Red Baker

Summary articles like this should be done once or twice a year to bring us up to date. This puts the state of knowledge in perspective.
Most folks have no idea that 90%+ of the time of the last million years were ice ages; that the average temperature for the past 12,000 years (since the end of the last ice age) was about 2 degrees warmer than today; much higher CO2 existed even as ice ages were starting; and temperatures have been flat for the last 16 years while CO2 keeps rising.

Oops–ignore the link I provided above. It refers to a mere public opinion survey. The real link is below.
Here’s how Wikipedia, at http://en.wikipedia.org/wiki/Surveys_of_scientists'_views_on_climate_change, spun the AMA/AGU survey by Mason:

STATS, 2007
In 2007, Harris Interactive surveyed 489 randomly selected members of either the American Meteorological Society or the American Geophysical Union for the Statistical Assessment Service (STATS) at George Mason University. The survey found 97% agreed that global temperatures have increased during the past 100 years; 84% say they personally believe human-induced warming is occurring, and 74% agree that “currently available scientific evidence” substantiates its occurrence. Only 5% believe that that human activity does not contribute to greenhouse warming; and 84% believe global climate change poses a moderate to very great danger.[8] [9]
8 Lavelle, Marianne (2008-04-23). “Survey Tracks Scientists’ Growing Climate Concern”. U.S. News & World Report. Retrieved 2010-01-20.
9 Lichter, S. Robert (2008-04-24). “Climate Scientists Agree on Warming, Disagree on Dangers, and Don’t Trust the Media’s Coverage of Climate Change”. Statistical Assessment Service, George Mason University. Retrieved 2010-01-20.
At http://stats.org/stories/2008/global_warming_survey_apr23_08.html

Here’s the heart of the report, taken from the link above:

Major Findings
Scientists agree that humans cause global warming

Ninety-seven percent of the climate scientists surveyed believe “global average temperatures have increased” during the past century.
Eighty-four percent say they personally believe human-induced warming is occurring, and 74% agree that “currently available scientific evidence” substantiates its occurrence. Only 5% believe that that human activity does not contribute to greenhouse warming; the rest are unsure.
Scientists still debate the dangers
A slight majority (54%) believe the warming measured over the last 100 years is not “within the range of natural temperature fluctuation.”
A slight majority (56%) see at least a 50-50 chance that global temperatures will rise two degrees Celsius or more during the next 50 to 100 years. (The United Nations’ Intergovernmental Panel on Climate Change cites this increase as the point beyond which additional warming would produce major environmental disruptions.)
Based on current trends, 41% of scientists believe global climate change will pose a very great danger to the earth in the next 50 to 100 years, compared to 13% who see relatively little danger. Another 44% rate climate change as moderately dangerous.
Seventy percent see climate change as very difficult to manage over the next 50 to 100 years, compared to only 5% who see it as not very difficult to manage. Another 23% see moderate difficulty in managing these changes.
A need to know more
Overall, only 5% describe the study of global climate change as a “fully mature” science, but 51% describe it as “fairly mature,” while 40% see it as still an “emerging” science. However, over two out of three (69%) believe there is at least a 50-50 chance that the debate over the role of human activity in global warming will be settled in the next 10 to 20 years.
Only 29% express a “great deal of confidence” that scientists understand the size and extent of anthropogenic [human] sources of greenhouse gases,” and only 32% are confident about our understanding of the archeological climate evidence.
Climate scientists are skeptical of the media
Only 1% of climate scientists rate either broadcast or cable television news about climate change as “very reliable.” Another 31% say broadcast news is “somewhat reliable,” compared to 25% for cable news. (The remainder rate TV news as “not very” or “not at all” reliable.) Local newspapers are rated as very reliable by 3% and somewhat reliable by 33% of scientists. Even the national press (New York Times, Wall St. Journal etc) is rated as very reliable by only 11%, although another 56% say it is at least somewhat reliable.
Former Vice President Al Gore’s documentary film “An Inconvenient Truth” rates better than any traditional news source, with 26% finding it “very reliable” and 38% as somewhat reliable. Other non-traditional information sources fare poorly: No more than 1% of climate experts rate the doomsday movie “The Day After Tomorrow” or Michael Crichton’s novel “State of Fear” as very reliable.
Are climate scientists being pressured to deny or advance global warming?
Five percent of climate scientists say they have been pressured by public officials or government agencies to “deny, minimize or discount evidence of human-induced global warming,” Three percent say they have been pressured by funders, and two percent perceived pressure from supervisors at work.
Three percent report that they were pressured by public officials or government agencies to “embellish, play up or overstate” evidence of global warming: Two percent report such pressure from funders, and two percent from supervisors.
Changing scientific opinion
In 1991 the Gallup organization conducted a telephone survey on global climate change among 400 scientists drawn from membership lists of the American Meteorological Association and the American Geophysical Union.
We repeated several of their questions verbatim, in order to measure changes in scientific opinion over time. On a variety of questions, opinion has consistently shifted toward increased belief in and concern about global warming. Among the changes:
In 1991 only 60% of climate scientists believed that average global temperatures were up, compared to 97% today.
In 1991 only a minority (41%) of climate scientists agreed that then-current scientific evidence “substantiates the occurrence of human-induced warming,” compared to three out of four (74%) today.
The proportion of those who see at least a 50-50 chance that global temperatures will rise two degrees Celsius has increased from 47% to 56% since 1991.
The proportion of scientists who have a great deal of confidence in our understanding of the human-induced sources of global climate change rose from 22% in 1991 to 29% in 2007. Similarly, the proportion voicing confidence in our understanding of the archeological climate evidence rose from 20% to 32%.
Despite these expressions of uncertainty, however, the proportion which rating the chances at 50-50 or better that the role of human behavior will be settled in the near future rose from 47% in 1991 to 69% in 2007.

It’s time for another round of that survey—six years have passed.