Guest Post by Ira Glickstein
A multi-modal probability distribution, such as the graphic below [from Schmittner 2011], cries out “MULTIPLE POPULATIONS”. Equilibrium Climate Sensitivity (expected temperature increase due to a doubling of CO2 levels, all else being equal) is distinctly different for Land and Ocean, with two peaks for Land (L1 and L2) and five peaks for Ocean (O1, O2, O3, O4, and O5).
When a probability distribution includes more than one population, the mean may, quite literally, have no MEANing! All bets are off.
Example of a Multi-Modal Distribution
According to the basic tenets of System Science (my PhD area) probability distributions that inadvertently mix multiple populations often lead to un-reliable conclusions. Here is an easy to understand example of how a multi-modal distribution leads to ridiculous results.
Say we graphed the heights of a group of infants and their mothers. We’d get a peak at, say 25″, representing the average height of the infants, and another at, say 65″, representing the mothers. The mean of that multi-modal distribution, 45″, would represent neither the mothers nor the infants – not a single baby nor mother would be 45″ tall!
If some “alien scientist” re-measured the heights of the cohort of children and their mothers over a decade, the mean would increase rapidly, perhaps from 45″ to 60″. If that “alien scientist” did not understand multi-modal distributions representing different populations, he or she might extrapolate and predict that, a decade hence, the mean would be 75″! Of course, actual measurements over a second decade, as the children reached their adult heights, would have a mean that would stabilize closer to 66″ (assuming about half the children were male). The “alien scientist’s” extrapolation would be as wrong as some IPCC predictions seem to be.
Implications of Multi-Modal CO2 Sensitivity
Schmittner says:
The [graph shown above], considering both land and ocean reconstructions, is multi-modal and displays a broad maximum with a double peak between 2 and 2.6 K [1 K = 1ºC], smaller local maxima around 2.8 K and 1.3 K and vanishing probabilities below 1 K and above 3.2 K. The distribution has its mean and median at 2.2 K and 2.3 K, respectively and its 66% and 90% cumulative probability intervals are 1.7–2.6 K, and 1.4–2.8 K, respectively. [my emphasis]
The caption for the graphic says:
Marginal posterior probability distributions for ECS2xC. Upper: estimated from land and ocean, land only, and ocean only temperature reconstructions using the standard assumptions (1 × dust, 0 × wind stress, 1 × sea level correction of ΔSSTSL = 0.32 K…). Lower: estimated under alternate assumptions about dust forcing, wind stress, and ΔSSTSL using land and ocean data.
So part of the cause of multi-modality is due to different sensitivity to dust, wind, and sea surface temperatures for the combined Ocean and Land data, and part due to differences between Ocean and Land. But, that is only part of the story. Please read on for how Geographic Zones seem to have different sensitivities.
Geographic Zones Have Different Sensitivities
Another Schmittner 2011 graphic, shown below, indicates how different the Arctic, North Temperate, Tropics, South Temperate, and Antarctic zones are. Indeed, there is a startling difference between the Arctic and Antarctic.
The thick black line represents the “climate reconstruction” (change in temperature in ºC) between current conditions and those of about 20,000 years ago during the Last Glacial Maximum. The LGM was the coldest period in the history of the Earth in the past 100,000 years. Note that the Tropics were about 2ºC cooler than they are now, the South Temperate zone was about 3ºC cooler, the North Temperate zone about 4ºC cooler, and the Antarctic about 8ºC cooler. However, according to the climate reconstruction, the Arctic was about 1ºC WARMER than it is today!
The estimated CO2 level during the LGM is 185 ppm, quite a bit below the estimated Pre-Industrial level of about 280 ppm, and about half that of the current measured level of about 390 ppm. Thus, IF CO2 DOUBLING CAUSED ALL of the temperature increase from the LGM to the present, the sensitivity for the geographic zones would range from +8ºC (Antarctic) to +4ºC (South Temperate) to +3ºC (North Temperate) to +2ºC (Tropics) to -1ºC (Arctic).
Of course, based on the Ice Core temperature records for several ice ages over the past 400,000 years, the warming 20,000 years after a Glacial Maximum tends to be significant (several degrees). Thus, while increases in CO2, all else being equal, do cause some increase in mean temperatures, it is clear from the Ice Core record, where temperature changes lead CO2 changes by from 800 to 1200 years, that something else causes the temperature to change and then the temperature change causes CO2 to change. Thus, it would be wrong, IMHO, to assign more than some small fraction of the warming since the LGM to CO2 increases.
The colored lines in the above graphic correspond to modeled temperatures based on different assumed CO2 sensitivities, ranging from 0.3ºC to +8.4ºC. The darker blue line, corresponding to a sensitivity of 2.3ºC, is the best match for the thick black climate reconstruction line.
IPCC CO2 Sensitivities are Mono-Modal and have “Fat Tails”
So, how do the IPCC AR4 Figure 9.20 graphs of Equilibrium Climate Sensitivity compare to the Schmittner 2011 results? Not too well, as the graphic below indicates!
First of all, notice that NONE of the individual IPCC graphs are multi-modal! Yet, taken as a group, there are several distinct peaks, indicating that each of the researchers characterized only one of a number of multi-modal peaks, and were inadvertently (or purposely?) blind to the other populations. Thus, the IPCC curves, taken as a group, seem to support Schmittner’s results of multi-modality.
For example, compare the green curve (Andronova 01) to the red curve (Forest 06). They hardly overlap, indicating that they have sampled different populations.
There is another, less obvious problem with the IPCC curves. Notice that they each have a relatively “normal” tail on the left and what is called a “Fat Tail” on the right. What does that mean? Well, a “normal curve” has a single peak, representing both the mode and the mean, and two “normal” tails that approach zero at about +/- 3ơ (Greek letter sigma, representing standard deviation). A mono-modal curve may skew to the left or right a bit, which would put the mode (peak) to the left or right of the mean.
The problem with the IPCC curves is that, in addition to the skew, the right-hand tail extends quite far to the right, out to 10ºC and beyond, before approaching zero. According to Schmittner 2011:
…High sensitivity models (ECS2xC > 6.3 K) show a runaway effect resulting in a completely ice-covered planet. Once snow and ice cover reach a critical latitude, the positive ice-albedo feedback is larger than the negative feedback due to reduced longwave radiation (Planck feedback), triggering an irreversible transition … During the LGM Earth was covered by more ice and snow than it is today, but continental ice sheets did not extend equatorward of ~40°N/S, and the tropics and subtropics were ice free except at high altitudes. Our model thus suggests that large climate sensitivities (ECS2xC > 6 K) cannot be reconciled with paleoclimatic and geologic evidence, and hence should be assigned near-zero probability….[my emphasis]
Based on the above argument, I have annotated the IPCC figure to “X-out” the Fat Tails beyond 6°C. I did that because any sensitivity greater than 6°C would retrodict a “total snowball Earth” at the LGM which contradicts clear evidence that the ice sheets did not extend equatorward beyond the middle of the USA or corresponding latitudes in Europe, Asia, South America, or Africa. Indeed, if Schmittner is correct, the tails of the IPCC graphs that extend beyond 5°C (or perhaps even 4°C) should approach zero probability.
Conclusions
Schmittner 2011 contradicts the IPCC climate sensitivity estimates and thus brings into question all IPCC temperature predictions due to human-caused CO2 increases.
It is clear from the several, widely-spaced peaks in the IPCC AR4 Figure 9.20 curves that Equilibrium Climate Sensitivity is indeed multi-modal. Yet, ALL the individual curves are mono-modal. Thus, the IPCC figure is, on its face, self-contradictory.
If Schmittner 2011 is correct that sensitivity beyond about 6°C is impossible based on the fact that Tropical and Sub-Tropical zones were not ice-covered during the LGM, the Fat Tails of all the IPCC Equilibrium Climate Sensitivity curves are wrong. That calls into question each and every one of those curves.
The multi-modal nature of CO2 sensitivity indicates that the effects of CO2 levels are quite different between geographic zones as well as between Ocean and Land. Thus, the very concept of a whole-Earth Equilibrium Climate Sensitivity based on a doubling of CO2 levels may be misplaced.
Finally, if CO2 is as strong a driver of surface temperatures as the IPCC would have us believe, how in the world can anyone explain the apparent fact that, given a doubling of CO2 levels, the modern Arctic is about 1°C COLDER than the LGM Arctic?
BOTTOM LINE: The Climate System is multi-faceted and extraordinarily complex. Even the most competent Climate Scientists, with the best and purest of intentions are rather like the blind men trying to characterize and understand the elephant. (One happens upon the elephant’s leg and proclaims “the elephant is like a tree”. Another happens to grab the tail and says with equal certainty “the elephant is like a snake”. The third bumps into the side of the elephant and confidently shouts “No, the elephant is like a wall!”) Each in his or her way is correct, but none can really understand all the aspects nor characterize or predict the behavior of the actual Climate System. And, sadly, not all Climate Scientists are competent, and some have impure intentions.
Thank you Ira for what I see as a very good post. The “multi-modal probability distribution” you describe is bound to bring about, just as you seem to suspect, wrong answers. –
The “mental leap” necessary to see and understand that averaging the Sun’s Wattage per square meter, i.e. dividing the “Solar Constant” by 4 is the same as halving the W/m² that actually does constantly fall upon (albeit on 50%) of the Earth’s surface is also bound to bring about wrong answers – even if it makes numbers on a plan, or graph, crunch up very nicely.
Oh, and R. Gates, my answer to your question/comment on December 18, 2011 at 10:40 am goes a bit like this: “On any Ice-core Graph” you will find that wheresoever the rising CO2 curve crosses the rising temperature (T) curve, that’s the point at which the CO2 takes over the warming.
If, however, you cannot find such a junction, then CO2 is probably always a product, or result, of any warming – of any type – anywhere.
Warming is very uneven. That is all this says. I think you are trying to draw rather overblown conclusions from that observation. In particular these “sensitivities” you are measuring are numbers which mean very little in our current context. The pattern of warming from the LGM to now is not the pattern of of warming that would be observed if the world were to warm from its current climate. These local “sensitivities” say nothing about what could happen to climate today.
@ur momisugly Arno Arrak:
December 18, 2011 at 2:54 pm
Well said sir!
Edim says:
December 18, 2011 at 3:08 pm
1. Where is our 30 Gt / year going?
One part remains in the atmosphere (in warmer years more), the other part goes into reservoirs (oceans mostly, in colder years more)
2. Why is the ocean a net sink of CO2, not a source (it’s getting more acidic/less alkaline due to CO2 take-up)?
Because of the anthropogenic input. Atmospheric CO2 is determined by climatic factors (temperature). So, the anthropogenic emissions will be distributed between the atmosphere and the oceans according to the climatic factors.
3. Where is the extra CO2 coming from if it’s not the oceans and it’s not fossil fuel burning?
Extra CO2 in the atmosphere is mostly from the oceans, maybe a small part is from burning carbon.
————–
So, Edim, why is the ocean now raising CO2 from 280ppm to 390ppm when it hasn’t been above 280ppm for the last 800K years, even though temperatures have changed more in that time (though probably not as fast)? We are burning 30 Gt / year, the atmosphere is gaining around 15 Gt / year (the rest going into the ocean) and atmospheric concentrations are higher than they have been for 800K years. It takes some serious mental gymnastics to not join those dots.
Really, there are lots more reasonable grounds on which to fight AGW than this one.
Cooling is very uneven. That is all this says. I think you are trying to draw rather overblown conclusions from that observation. In particular these “sensitivities” you are measuring are numbers which mean very little in our current context. The pattern of cooling from the MWP to now is not the pattern of cooling that would be observed if the world were to cool from its current climate. These local “sensitivities” say nothing about what could happen to climate today.
CynicalScientist says:
December 18, 2011 at 3:43 pm
Warming is very uneven. That is all this says. I think you are trying to draw rather overblown conclusions from that observation.>>>
LOL. The CAGW meme is that all the data shows that is the case. They only allow that it will be more pronounced at the poles than at the tropics, other than that they repeat over and over again the ridiculous notion of CO2 doubling causing an increase in the “average” temperature of the earth. How else are we to interpret their doublespeak? Is there anywhere in the IPCC reports that speak to the notion of the warming being uneven? Do they explain anywhere that the bulk of the warming will come at night time lows in winter at high altitudes? Do they explain anywhere that the least warming will come in the tropics, and it very well may be so small at to be unmeasurable? Do they not point repeatedly at the arctic screaming “its happening already” and “polar amplification” when they know very well that in any warming cycle small that is exactly what to expect and the fact that there is no corresponding warming in the tropics is just the laws of physics working exactly as expected and so even if (BIG “IF”) CO2 is driving the warming, it is nearly meaningless in the global picture?
Of course then there’s their favourite rebuttal when data shows that the earth had been warming since the LIA, that temps were warmer than now all over the world during the MWP, THEN they stick their nose in the air and say…”well, those were just regional”.
REALLY? When there is no global pattern of warming, it just means the warming is “uneven”. But when data shows that warming and cooling happen at the same time in different places, its just regional. Would you clowns please pick one? Warming is uneven, ot it is even. Oddly, no matter which one you pick, your argument is sunk. That’s why you clowns argue one way in one situation, and then use the exact same data showing the exact same thing to argue a different way in a different situation.
Itz one thing to grasp at straws, another to poke yourself in the eye with them.
R. Gates says:
December 18, 2011 at 12:50 pm
Andrew30,
Your use of short-term temperature series, subject as it is to short-term climatic forcing and variations, is inappropriate when looking at the longer-term effects as from CO2.
We have no direct evidence CO2 has any longer term effects. The physics tells us CO2 has an immediate effect. What the effect is, an hour, a day, a year later we simply don’t know, because feedbacks are so poorly understood.
And as for the multi-modal graph above. If it shows anything, it shows we have no idea what the climate’s sensitivity to 2X CO2 is.
One thing it does show is that a climate sensitivity of less than 1 is politically unacceptable.
Some thing to keep in mind:
1. The transition from glacial to interglacial conditions is very fast. Probably in less than a century we go from glacial temperatures to interglacial temperatures.
2. Transition from interglacial to glacial is gradual overall but very unstable. Temperatures of an interglacial period generally decline as it progresses. Temperatures are generally very stable during an interglacial, much more stable than during interglacials, but they tend to decline. Toward the end of the interglacial, temperatures go unstable and seem to be characterized by increasingly cold cool periods separated by a jump to nearly temperatures.
3. Glacial periods have extremely unstable climate. Temperatures can change from extremely cold to nearly interglacial temperatures and go back to deep glacial cold in less than a millennium. These interstadials can see quite warm temperatures but they don’t “stick” and we slip back into cold very quickly.
4. Glacial periods tend to get colder as they progress.
5. Glacial periods end just as they reach their coldest time.
So if solar forcing from orbital changes activates these cycles, and if these orbital changes are gradual and ongoing, why don’t we see the glacial period slowly warm into the interglacial? It is likely that we pop out with an interstadial event when conditions are good for allowing us to stay there for a while. In fact, we very nearly had an interglacial about 34,000 years ago when we had a major interstadial where got very warm, to temperatures seen during the Holocene (warmer than temperatures during the 8.2ky event), and it stayed relatively warm for a considerable period gradually cooling, then falling quickly to very cold temperatures only to nearly pop completely to Holocene temperatures again very quickly 30,000 years ago.
There were 11 such rapid warming/cooling events in just the last 40,000 years. And by rapid, I mean extremely rapid. I am talking global warming/cooling from temperatures of a deep glacial to near modern temperatures and back again to glacial conditions in less than 500 years in some cases. Rapid warming was generally completed in much less than a century. The Younger Dryas ended in a period of 50 years warming from glacial conditions to pre-borial in the easy span of a single human’s lifetime.
The point is that there is a very well-documented history on this planet of extreme climate change. Much more extreme climate change than we have experienced this century. None of these extremely climate change events (over a score of them, both warming and cooling in only the last 40,000 years) can be attributed to atmospheric CO2. These are climatic tsunamis.
The problem with these “climate scientists” is they depend on the illusion that climate is somehow stable. It isn’t. The 8.2ky event, the Little Ice Age, the Younger Dryas and the warming following these events are nothing. Nature can throw some mighty fastballs. I am seriously of the opinion that these so-called “scientists” don’t really have a clue what they are talking about. Too clever by half, if you ask me.
R. Gates says:
December 18, 2011 at 10:40 am
“The central question is: what will the effect be of raising CO2 to levels not seen in at least 800,000 years over a time-frame so short so as to not find a parallel in the geologic record?”
Well, the effect of NOT raising the CO2 level is a mile-thick sheet of ice covering much of the northern hemisphere wiping out a good fraction of our civilization not to mention rivers and lakes and wetlands and forests and etcetera.
Personally I’m willing to gamble that raising CO2 level can’t be worse than not raising it.
It almost seems inevitable that when you’re teetering on the edge of an ice age like the earth is today what with the Holocene interglacial getting statistically long in tooth it’s almost inevitable that some perfect storm of volcanoes or one real doozy will be the straw that breaks the camel’s back and ice age here we come. As an engineer I’d just as soon have a bigger safety margin and if manmade CO2 buys us a few degrees, right where we need it in the high northern latitudes where glacial expansion begins. Now throw the general benefits of higher CO2 levels for plant growth and water usage and longer growing seasons and raising CO2 level is such a good thing it’s kind of nutty to worry about it. Don’t be nutty, Gates.
davidmhoffer says:
December 18, 2011 at 4:54 pm
” Is there anywhere in the IPCC reports that speak to the notion of the warming being uneven?”
Yes.
It’s nice that you asked. You should ask more and state less, Mr. Jedi Salesman.
There’s some meat here that Pat Frank might be interested in. Surprised he has not commented.
Mark
from: Jedi Scientist
to: Jedi Salesman
Frequently Asked Question 11.1
Do Projected Changes in Climate Vary from Region to Region?
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-11-1.html
ROFLMAO@u
Exactly so. And furthermore the pattern of cooling will not simply reverse the pattern of warming.
Some of you seem to think I am defending AGW. You should read more carefully.
“Those who see houses of cards think that if any piece is removed, the whole lot falls down. Most scientists I know, including myself, are “jigsaw” types. We have to see how this result fits in with the rest of what we know, and continue testing assumptions, before we can come to a consensus about what’s really going on here.”
The reality is that most scientists want to believe they are dealing with a jigsaw puzzle and will strongly reject evidence that what they are in fact dealing with is a house of cards with key supporting cards missing (as shown by the evidence).
This has been documented by Kuhn and others. Although there is little research on it as a socio-psychological phenomena. IMO it is a characteristic all humans share and isn’t specific to science.
Thanks for that Ira.
With Moore’s Law holding, I would expect that it will be several decades before any useful predictions from models will exists. Climate is just too complex. Besides, IMHO, science is provisionary. Otherwise Newton’s Law’s would be universal (or should I say multiverse).
Harry Dale Huffman says:
December 18, 2011 at 2:03 pm
Harry, Harry, Harry…
I’ve told you many times your temperature/density notions about planetary atmospheres is so totally misunderstanding gas laws it isn’t even funny.
Well, actually it IS funny.
Venus is hot because of its atmosphere. You have that part right. You also have the part right about the high surface temperature not being caused by CO2 retaining solar energy through the so-called greenhouse effect. There’s no sunlight even gets close to the surface on Venus. It’s pitch black. The surface is so hot because the temperature gradient from the molten core of the planet does not take a radical dip downward close to the surface as it does on the earth. That’s because the 90X thicker atmosphere of Venus insulates the crust a lot better than our wispy atmosphere and heat from the mantle rises further because it isn’t being carried off as fast. So you see it isn’t the sun heating the surface of Venus it’s the molten interior of the planet that’s heating it. The temperature gradient of the planet from core to surface is different on Venus because the surface is far better insulated.
And from the standpoint of the UN Agenda-21 people, that is a feature, not a bug. Most of what is now Canada being deposited by a glacier in the middle of Indiana is a “sustainable” development as far as they are concerned. There’s no sustainable development like no development at all. A lack of development can be sustained forever.
Ira Glickstein, PhD says:
December 18, 2011 at 3:03 pm
Have a close look at the Ice Core graphs and you will see that temperatures begin their rise from the depths of Glacial Maximum at the very moment in time that CO2 levels are at their lowest.
Ira, there is nothing in this to suggest that CO2 is anything but an inverse forcing for climate. As you state:
” at the very moment in time that CO2 levels are at their lowest. Temperatures rise for hundreds of years” “when CO2 levels are at their very highest, temperatures begin a relatively rapid fall”
Where is the observational evidence that increasing CO2 leads to increasing temperatures? All the ice cores show is that climate science has cause and effect backwards.
John B says:
December 18, 2011 at 4:31 pm
So, Edim, why is the ocean now raising CO2 from 280ppm to 390ppm when it hasn’t been above 280ppm for the last 800K years,
Likely because this interglacial has lasted longer than average, allowing more CO2 to out-gas, or because we are using different techniques to measure modern CO2 levels as compared to 800K years ago.
What we do know is that 280ppm is very low in terms of CO2 levels over most of the past billion or so years that life has existed on this planet. CO2 levels this low are typically only seen during ice ages, which are not exactly “life friendly”.
Harry Dale Huffman says:
December 18, 2011 at 2:03 pm
You won’t believe this but when I read your article linked above and saw the factor 1.176 I could not believe it myself, for I recognized that figure, from doing some analysis on Venus’s atmosphere and temperatures but from a totally different direction. I was tracing energy transfers in relation to the mass attenuation coefficient across Venus’s entire atmospheric column, from surface to TOA, Venus’s atmosphere having 94 times the mass compared to earth.
The brunt of my analysis was why Venus, with a surface radiative power of 17004 Wm-2 (740K) can transfer to a 65.3 Wm-2 power at the TOA, why. There is a large attenuation of radiation as you progress upward from the surface to the TOA. (and amazingly that same effect occurs in our atmosphere by pure mass but by 94th root to that on Venus due to the 94 times mass)
Would you like to see that parallel, if your are still monitoring this thread? It really floored me and it would take me a little while to type it up in an understandable form.
Dave Springer says:
December 18, 2011 at 5:38 pm
from: Jedi Scientist
to: Jedi Salesman
Frequently Asked Question 11.1
Do Projected Changes in Climate Vary from Region to Region?
http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-11-1.html
ROFLMAO@u>>>
Why thank you for that Mr Springer. For once you’ve managed a retort with relevant information, though your perserverance in demonstrating that your are a complete and total jerk is also on full display.
On the other hand, the link you provide speaks to regional factors that cause idiosyncratic warming. However, the article was in regard to the uneveness of various factors including geographic differences just as the link you posted suggest. Despute this, as the article also discusses, the IPCC estimates for CO2 sensitivity are mono-modal while the data clearly shows that sensitivity is multi-modal.
In other words my dear friend, the article you linked to indeed says that warming will not be uniform. However, the discussion was in regard to sensitivity directly attributed to CO2. In terms of sensitivity to CO2, the IPCC has been quite clear that they consider it uniform. In fact, they calculate an increase in radiance at TOA as 3.7 w/m2 on a 24 hour basis. Given that they claim also the source of the radiance is LW absorbed from earth surface and re-radiated back to earth, one can only wonder how the tropics, radiating as much as 450 w/m2 or more, and the polar regions, which may be under 200, can possibly result in a uniform TOA increase of 3.7w/m2. Further, since the poles are nearly devoid of water vapour, which dwarfs CO2 as a GHG, the imbalance and lack of uniformity between the tropics and the poles should be larger still. Furthermore, the tropics are net absorbers of energy, while the poles are net losers of energy.
In other words, in terms of sensitivity to CO2 increases, there is nothing possibly uniform at all. Despite which, the IPCC attempts to pain that picture. Please note that while the link you supplied does in fact explain the variations expected in warming due to regional wind patters and so on, it says not one damn thing about variations in sensitivity to CO2.
crosspatch says:
December 18, 2011 at 12:34 pm
Does the bad guy have to be “Jim”?
wayne says:
December 18, 2011 at 6:53 pm
Would you like to see that parallel, if your are still monitoring this thread?
A number of readers that have followed Dale’s work would likely be interested.
The work of Schmittner et. al. is just another piece of computer simulation.
The post here analysing a multi-modal description is implicitly accepting Schmittner et. al.
Why should this particular simulation be trusted over any other?
It will likely be a period such as the Little Ice Age that we simply aren’t able to recover from. If you look back over the past 2000 years, we have had several cool periods. Each one bottoms out a little cooler than the previous did. Each warm period tops out a little cooler than the previous one did. We know that this warm period is colder than the MWP because we can’t yet establish farms in Greenland in places where crops were grown then in Greenland. Same is true for valleys in Scandinavia and the Alps that are currently too cold or too wet from retreating ice to grow a crop but supported crops during the MWP.
Looking at the various literature in paleoclimatic reconstructions of all sorts and seeing the various recurring cycles that seem to appear in all of them, it would seam reasonable, simply based on the number of these conducted using different proxies by different people at different times that we are not likely to get much warming between now and the end of this century.