Bishop Hill Falsifiability in my lifetime
Jan 16, 2014 Climate: Models An article on the Nature website looks at the failure of global temperatures to rise in line with the climate models and finds a possible explanation in the Pacific Decadal Oscillation. I notice what may be the start of a new meme emerging:
...none of the climate simulations carried out for the IPCC produced this particular hiatus at this particular time. That has led sceptics — and some scientists — to the controversial conclusion that the models might be overestimating the effect of greenhouse gases, and that future warming might not be as strong as is feared. Others say that this conclusion goes against the long-term temperature trends, as well as palaeoclimate data that are used to extend the temperature record far into the past. And many researchers caution against evaluating models on the basis of a relatively short-term blip in the climate. “If you are interested in global climate change, your main focus ought to be on timescales of 50 to 100 years,” says Susan Solomon, a climate scientist at the Massachusetts Institute of Technology in Cambridge.
The idea that the predictions of climate models are only good over periods this long seems to represent a considerable upping of the ante, but it's one that I have heard elsewhere in recent days - if I remember correctly it was also mentioned by David Kennedy in his evidence to the Energy and Climate Change Committee. In the past, the community has stood by a period of 30 years (at least when it suited them), but it may well be that the public start to realise that the models have been running hot over periods of several decades, the climate modelling community has been forced to extend the limits.
100 years should ensure that all concerned make it to retirement.
Reader Comments (202)
Kim
Research Milankovixh cycles.
Mike Jackson
1. the arbitrary figure assigned to pre-industrial CO2 levels has been challenged; 2. the date from which that arbitrary figure started to increase appears to be up for debate (you are now saying 'late 19th century' while others give various dates as early as mid-18th century); 3. we have managed to get modellers to start admitting that their models are not all that good with clouds, PDO, AMO, cosmic rays even though extracting this concession has been like drawing teeth; 4. CO2 concentrations lag temperature and not the other way round.
You have made four statements straight out of the Heartland Institute book of sceptic slogans. Kindly show your evidence that any of them are worth taking seriously.
You complain that I do not supply proper evidence. Show me how it should be done.
Dave Salt
Could you be more specific. What contribution do you attribute to you different natural variations? Please include the large confidence limits you describe. It is much easier to falsfy specific statements than vague BS.
Since few readers will have lasted this far on the thread, may I just take up a little more space by reminding them that scientists have been ploughing this fsrrow since 2008, Following the dramatic drop in global temperatures in 2007, which saw them fall temporarily by as much as the entire net temperature rise of the 20th century, one of the first attempts to explain this as just a temporary blip, "masking the underlying warming trend". came in a 2008 paper I referred to in my book The Real Global Warming Disaster, as follows:
In May, for instance, considerable media coverage was given to a new study published in Nature which conceded that global temperatures might not rise over the next decade, ‘as natural climate cycles enter a cooling phase’. But after 2015, Nature’s readers would be reassured to know, global warming would again pick up, causing temperatures to rise even higher than those of 1998. This was based on the projections of a computer model run by a British scientist, Noel Keenlyside, at the Liebniz Insttute of Marine Sciences at Kiel in Germany, which based its results on predicting changes in the Gulf Stream, the ‘meridional overturning circulation’ (MOC) which brings warmer water across the Atlantic to Europe.
Keenlyside accepted that the IPCC’s forecast of a 0.3 degrees temperature rise during the current decade had not been borne out. But this was only, he suggested, because its models were not programmed to take proper account of ocean currents such as the Gulf Stream. His own model, he insisted, confirmed that by 2015 the warming caused by CO2 would re-assert itself, carrying temperatures up to record levels.
This might have given some cheer to the warmists, but it was hardly a ringing endorsement for the efficiency of the IPCC’s models, Indeed, curiously enough, another significant ocean current event overlooked by the IPCC’s models was reported by NASA on 21 April. This was the shifting of the Pacific Decadal Oscillation (PDO) ‘from a warm to a cool phase’. As was pointed out by Anthony Watts, the alternations of the PDO from between its warm and cool phases had coincided with each of the main temperature shifts of the 20th century: warming after 1905, cooling after 1946, warming after 1977. Now it was again shifting into a cool phase. Was it not odd that the IPCC’s models had not been programmed to take account of this?
I find that this is typical of the exceptionally able environmental PR people. Somehow, with enough PR about all the bad things that X environmental issue will cause, things get turned around, and it is up to critics (skeptics in the case of climate issues) to prove that something that might happen decades from now is unlikely to happen. Since this can never be proved, voila! An impregnable defense.
8 years ago, if you mentioned a lack of warming, and pointed to natural variability, you were rubbished because it was still within the 95% error bars.
3 years ago, if you mentioned lack of warming, and pointed to natural variability, you were rubbished and called a denier.
Now, even Nature magazine (only because they have to acknowledge reality) acknowledges the pause and even attributes it to natural variability. No apologies, though.
The whole hysteria is still real, and if you want to debate them, make an appointment for 2060 or thereabouts.
And the Guardian and their ilk will support them.
Models are the new Bible. In which there is a literal interpretation, which shall not be questioned. Like the tea party, but different. Only slightly.
"Since few readers will have lasted this far on the thread"
Christopher...we are not politicians.
CB - good to see that that you are reading here. And if I may go OT for moment, well done for all your efforts to expose the injustices of the Court of Protection and state-endorsed baby snatching.
Never having read the Heartland Institute Book of Sceptic Slogans I couldn't comment on what it contains but I do know that — a bit like "comedians" who still think saying 'Thatcher' is a sure way to get a laugh — warmists believe that saying 'Heartland' is enough to debunk any argument that has been put forward. It's sad, really, that otherwise moderately intelligent human beings fail to recognise that what they are doing is not rebutting anything by that sort of ad hominem (ad institutem?) attack but merely demonstrating the paucity of their own argument.
EM
I am getting rather tired of showing you "how it should be done". Start from the fact that previous warming periods have been broadly the result of natural variation (I say 'broadly' because it would be bizarre if mankind over the centuries had had no effect on local climate variation) and provide empirical evidence that the 1975-2000 warming was fundamentally different to all previous similar events.
So far (and I have been asking this question for nearly 15 years now) all I get is hand-waving, invective or the sort of diversionary tactic that you have engaged in above.
Christopher Booker
First let me endorse lapogus' comment. More power to your elbow!
Your arrival to mention the PDO is serendipitous in the light of Entropic Man's off-hand dismissal of my comment. But surely if we fully accept that the IPCC's remit was to investigate anthropogenic global warming with a view, by implication at least, to endorsing the views of Strong and his allies and facilitating a situation which would make their ambitions for the earth realisable then there is no reason to include such natural phenomena in their models.
[Those who think I'm exaggerating or finding conspiracies should remember that the IPCC is a UN creation and a political, not a scientific, body though it claims to use the "best" science to reach its conclusions.]
The important thing is to keep the message simple and on-track. The last thing the IPCC and its useful idiots in the environmental movement expected was that there would be enough scientifically knowledgeable people able to coalesce into the sort of critical mass that we have in the sceptic blogosphere, as witnessed by the odd collection of half-truths and distortions that they have used when caught out in some simple error, like the 2035 date for end of Himalayan glaciers.
What is so dangerous about this obsession with CO2 and warming is that there appears to be very little chance of the catastrophe they have prophesied (and continue to prophesy) actually coming to pass, certainly within the lifetimes of our grandchildren, while the alternative, a cooling period which may be just around the corner (or may not but we don't know because nobody is bothering to research it), is likely to be more catastrophic in terms of an increased demand for energy and a possible dip in crop yields.
Mike Jackson
Should I stop holding my breathe now?
Working now. We'll go into this more this evening.
Until then, could you print out a copy of the global temperature graph from GISS and mark off the peaks and troughs for the PDO/AMO 60 year cycle and the decadal solar cycle. Use the 5 year moving average. It filters out a lot of the weather noise.
SandyS
I did suggest not holding your breath would be best!
EM:
So, you admit that there are cycles that can affect global temperatures over which Man has no control. Can you accept that there might be other, similar, cycles that we have yet to find? Can you accept that there could be other non-cyclic influences over which Man has no control that could affect global temperatures?The whole “cAGW” scare was based upon:
a) global warming being a Bad Thing, and must not be allowed to happen;
b) CO2 being THE driving force behind global warming; and,
c) the rise in CO2 being from “fossil” fuels burned by humans.
The evidence is mounting to suggest that none of these fit the case. Why do you continue to deny the obvious?
Mike Jackson (Jan 18, 2014 at 9:30 AM): I have tried that argument on others, to be informed: “Ah! But this time, it’s humans that are causing it!”
When you get that sort of logic that actually contains no logic whatsoever, you know that you may as well give up arguing and let the poor soul continue their pointless digging.
RR
I am one of nature's optimists. I can usually see both sides of an argument. I try to find the best in people.
And so I continue to try and reason with them in the face of all the evidence that they do not want to be reasoned with.
But tell me ...
In what other sphere of human activity would evidence that catastrophe is not going to happen and that things are perhaps better than they thought greeted with howls of protest. Do these people want there to be catastrophe?
And if so, can they explain why?
MJ: like you, I, too, am inclined to be optimistic, and see the best in others. However, I do try to be pessimistic, as the inevitable surprises a pessimist experiences tend to be pleasant surprises.
As for the thinking behind the growing evidence of non-catastrophe occurring when once was thought the opposite being met with such protests, I am afraid we will have to look to the psychiatrists; but, then, when I first heard about Freud (I was about 14), I did a little investigating, and came away with the distinct impression he was a fraud, and thereafter changed his name (though was and have been ridiculed for it since – as a BTW, I always preferred Jung’s theories over Fraud’s). It has turned out that much of his “research” actually was fraudulent, so, which of the present-day crop of trick-cyclists, none of whom hold the same kudos that Fraud inexplicably retains, will give us a reasonable answer?
My own hypothesis, for which I would never get the grant for further study, nor do I have the skills to pursue, is that these people are the modern doomsayers. In times of yore, they would walk the streets, unwashed, tearing out their hair and tearing their clothes, waving (or wearing – or both!) placards, and wailing: “The end is nigh!” and generally been ignored or, at worst, ridiculed. They have borne a grudge for this treatment, and have, somehow, managed to get a toe-hold in the corridors of power, so are now wreaking their terrible vengeance upon us, the more sensible non-doomsayers.
RR
As for Freud, it was pointed out to me when I was studying educational psychology that since most of his theories were based on his experiences with his clients the majority of whom were middle-aged, middle-class, Jewish, Viennese, and predominantly female it was advisable to take these factors into account when drawing wide conclusions.I agree with you about modern doomsayers. If by chance you haven't read Booker and North's Scared to Death, I suggest you do. Without commenting on the extent to which they were right or wrong in the conclusions they drew, it it still a fascinating study in how easily people can be persuaded to buy into the prophecies of doom. Also remember Mencken's adage:
I think it might be useful for most scientific researchers to keep at the back of their minds that any set of factors which applies with any certainty only to a very small subset of the whole is not likely to be a particularly good proxy for the rest of the human race / planet / whatever!
The evidence is mounting to suggest that none of these fit the case. Why do you continue to deny the obvious?
Jan 18, 2014 at 11:14 AM | Unregistered CommenterRadical Rodent
What evidence? You all refuse to tell me. If it is so obvious you should be able to give me chapter and verse.
For example, Mike Jackson tells me in his point 1 that the accepted historical pattern of CO2 has been challenged. Who by? Where? On what data?
Did you copy the graph? It's here if you missed it.
http://data.giss.nasa.gov/gistemp/graphs_v3/Fig.A2.gif
Regarding 3. , I'd prefer you to identify the peaks and troughs of the PDO and solar cycles for yourself, rather than just take my word for them. Back later.
Could you explain that please, Entropic man? It appears to me like a comment you didn't intend to publish. I thought you were a retired school teacher?
Entropic man (Jan 17, 2014 at 11:28 PM) said "Could you be more specific. What contribution do you attribute to you different natural variations? Please include the large confidence limits you describe. It is much easier to falsfy specific statements than vague BS."
I'll assume you're actually interested in civil debate and not, as your last sentence suggests, simple here to antagonise. I’ll also point out that I never ‘described’ or said anything about large confidence limits… this is the second time in this thread that you’ve fabricated statements!
If the measured temperature rise over much of the last century was due to a simple combination of CO2 and PDO, it should be possible to take plots of temperature and CO2 over this period…
http://eatingjellyfish.com/?tag=atmospheric-co2-levels
…while taking special note of the way that the human component of CO2 has evolved…
http://tiki.oneworld.org/time_machine/detail/CO2_levels.htm
…to get an eye-ball estimate of just how much of the temperature rise was due to CO2.
Using the plot from the Nature article and those in the above links, my eye-ball estimation of the temperature rise due to CO2 (i.e. delta between complete PDO cycles, peak-to-peak or trough to trough) is less than 0.7 degC/century. Similarly, the rise in the human component of CO2 seems to be a steady 200ppm/century.
These eye-ball estimates suggests that a doubling of CO2 from a pre-industrial level of 280ppm to 560ppm will force a temperature rise of less than 1.1 degC, which is in-line with predictions from the ‘classical’ greenhouse effect but well short of those predicted by the ‘enhanced’ greenhouse effect (i.e. the evidence does not support CAGW if PDO is assumed to have contributed to historic temperature trends).
I know that this assessment is far too simple to draw any meaningful conclusions, but it does illustrate that the CAGW hypothesis is not the clear/obvious answer as some would have us believe.
EM:
a) Nothing has been seen that shows that the slight rise in temperatures since the Little Ice Age has been detrimental to the planet; everything I have seen suggests that it has been positively beneficial. Most people prefer the warmer winters we are now enjoying (skiers may howl me down, here).
b) CO2 levels in the atmosphere are rising; temperatures are not – ergo, CO2 is NOT the “driving force” for temperatures. If it can be over-ridden by “natural variation”, then, perhaps, natural variation is the actual “driving force” behind temperature rise.
c) The human contribution to the rise in CO2 by the burning of “fossil” fuels is generally acknowledged to be about 3%. Unless the human-origin CO2 has special. malevolent qualities, how can we so categorically blame humanity for global warming?
The evidence that you so desperately seek is all around you, yet you refuse to see it – there are no catastrophes outside the normal amount that the world springs upon us (though, I have to admit, even one is one too many, especially for those engulfed in it). What extremes there have been have often been the wrong sort of extreme – the lowest number of tropical revolving storms (hurricanes, typhoons, etc.) for decades, and when one does occur, it tends to be a low-energy, weak storm. If you cannot see what is in front of your nose, what chance have we of helping you to see it?
David Salt
Thank the lord for a man willing to debate!
I use the GISS graph I linked above as a ready reckoner for two reasons. It presents the data in a visually simple manner. It is also a dataset which makes some attempt to include the Arctic.
Using that graph the approximate 5-year average temperature anomalies for 1880, 1910 and 2010 are -0.2, -0.45 and 0.57. The increase from 1880 to 2010 becomes 0.77 or 0.59C per century. We agree.
I would agree with your 200ppm/century too, though it is accelerating. IPCC estimate that 560ppm will arrive about 2160 if business-as usual continues.
Using the 0.59C/century rate that would produce a temperature rise between 1880 and 2060 of 1.06C for the doubled CO2.You make very good estimates.
Now for our differences. As you say, cAGW is more complex than simple figures.
One problem is lag. The temperature increase lags behind the CO2 increase because it takes time for the extra heat to spread throughout the system and reach equilibrium. Thus 2013 temperatures reflect the CO2 concentration some years ago.
Even if concentrations stabilised at 560ppm in 2060 the temperature would continue to increase for some time. The final temperature rise is the equilibrium climate sensitivity, ECS. The rise you see en route is the Transient Climate response, TCR.
Your estimate is based on TCR, rather than the full ECS and would underestimate the full climate sensitivity.
You also suggest that PDO is sufficient to explain much of the temperature record. This overlaps with Mike Jackson's third point,so we can turn to the GISS graph. PDO/AMO is usually quoted as a 60-65 year cycle. That gives just over 2 full cycles since 1880, so we should be able to get some information from the graph about timing and effects.
By inspection I estimate two PDO peaks in the 5-year average in 1941 and 2003, with troughs in 1880, 1910 and 1972. The average difference between adjacent peaks or troughs is 0.25+0.56+0.06+0.58/4 = 0.36C, about 60% of that 0.59C/century range.
PDO and other cycles should be temperature neutral over more than one cycle since, if there were no long term trend, each cycle should peak at the same temperature.
In practice there was a 0.26C increase from the 1880 peak to 1941 and another 0.52C to the 2003 peak. These would be due to other effects, not PDO.
The 11 year solar cycle has the same limitation, Mr Jackson. It can produce a +/- 0.1C short term variation, but not explain the long term trend.
Michael hart
I trust my comment to Dave Salt indicates why I referred to the GISS graph.
Radical Rodent
The title of this thread is "Falsifiability in my Lifetime". That's the problem; you are too impatient.
You are saying "There's no problem" before the real consequences of the problem have had time to develop. The small changes seen to date are the precursor.
Perhaps you should consider the man falling off the Empire State building. As he passed the 40th floor he called "It's fine so far." :-)
Mike Jackson
Re. Point 4
Massive vulcanism in the Cambrian and Permean produced CO2 which preceded the resulting temperature increase. Despite Radical Rodent's doubts CO2 increase in the modern era is running ahead of the temperature increase it will produce, especially in the last decade. If you are unsure on this point consider the difference between ECS and TCR which I discussed with David Salt.
Entropic Man:
Eh? What on Earth are you talking about? Perhaps you fear a train crash while the train has yet to leave the station – what consequences of global warming as we have experienced it so far do we have to fear? Nothing we have yet experienced is anywhere close to falling off the Empire State Building (from which floor, by the way – you do know it is stepped, so a drop from the top will probably not reach the 40th floor?).
In my lifetime, to date, the temperatures are reported to have risen less than 0.5°C. Even if these were to rise by twice as much over the rest of my life, what’s the scare?
However… the rise has paused, and has been paused for over 15 years; indeed, the indications are that the temperatures are likely to fall. What does worry me is that we are soon to plunge into another ice age. Be it a little one, or a major one, either will be truly catastrophic, and no amount of “fossil” fuel burning will be able to keep it at bay.
Entropic man (Jan 18, 2014 at 10:43 PM) said "You also suggest that PDO is sufficient to explain much of the temperature record".
I did *not* suggest that PDO is sufficient to explain much of the temperature record, said *if*… why do you keep making things up like this?
I said “If the measured temperature rise over much of the last century was due to a simple combination of CO2 and PDO” because I wanted to assess the consequences of the Nature article’s hypothesis and its likely impact on CAGW theory. The result seems to falsify CAGW but tends to verified AGW, which would support the ‘lukewarm’ view of climate change.
Concerning TCR versus ECS, all I did was consider linear rises in both the CO2 and temperature. This is clearly an oversimplification if only because the warming effects of CO2 will diminish at higher concentrations due to saturation, so I think it’s rather unwise to try and extract too much detail from such a crude analysis. Nevertheless, I’m glad you agree with the general method.
David Salt
." the evidence does not support CAGW if PDO is assumed to have contributed to historic temperature trends"
Perhaps I am reading more into this than you intended.
I'm not sure that the CO2 greenhouse effect will saturate with increasing concentration. At 15 micrometres it has already saturated. This is demonstrated by the 50% absorption in the OLR at the spot frequency.
However, band spreading is already causing absorption across a band between 13 and 17 micrometres. This will continue to increase with increasing concentration.
http://wattsupwiththat.com/2011/02/28/visualizing-the-greenhouse-effect-atmospheric-windows/
There is also the reductio absurdam argument of Venus. With a high pressure atmosphere, 95% CO2 and 433C surface temperatures saturation does not seem to have been a limitation.
Interesting term "micrometres" although its an official SI unit since the late 60's, "micron" is still more frequently used.
Entropic Man
After looking at the Graph posted by Lapogus here which is more up to date than the one I found and apparently your tablet can access could you tell me why the recent warming and peak is so very different from any of the previous ones in the current inter-glacial and therefore indicating manmade doom?
As this is my third time of asking and I can find no response can I assume there is none?
Sandy S
Briefl, because for most of this interstadial the orbital configuration favoured warming and we got warming. Now the configuration favours cooling and we are getting warming instead.
It is not clear from this graph how much of the short term variation is noise, especially as it is based on one ice core. If you look at an ensemble curve like that in Marcott et al a lot of the noise disappears.
Dave Salt, Mike Jackson
The irony struck me this morning. If PDO is powerful enough to accelerate warming during the "warm" phase and pause it during the "cold" phase, we should expect the 20th century pattern to continue, with 30 yeasr periods of rapid warming to alternate with 30 year pauses.
This would mean that the next warming period will resume in 2030 and " no warming for 17 years" is evidence that global warming is right on schedule. :-)
EM Milankovitch?
Not without problems in itself nor well understood so we're (humanity) are still guessing on that as well. The optimums for the current interglacial ended about 3500 years ago then warmed again for 1300 years to 1250 AD and we're still on the cool side although at the top of series of declining peaks, Whether it goes down or up from now is pure conjecture.
Why take a negative view?
Too simplistic, EM
You're still obsessed with the idea that the main driver of climate is CO2 — correction, that this time the main driver is CO2.
Gore lied in his film An Inconvenient Truth by linking CO2 concentrations to temperature without factoring in the ~800-year time lag.
On a shorter timescale the 20th century does not support his lie either since CO2 and temperature which were supposedly more or less in lock step have not been for most of the century.
Now that we have another pause/decline/slowdown (following the 1880-1910 and the 1940-1970 ones) while CO2 has been rising steadily we have the latest excuse that its last decade's CO2 that is driving temperature, still without a smidgin of empirical evidence that anything that has happened during the last 100 years is in any way outside the bounds of what has occurred many times in the past.
Will you please explain why climate science is allowed to think up a new idea and demand the rest of us accept it or in effect prove the negative rather than postulate a new idea based on evidence that the existing idea is not correct? Science advances by proving that existing hypotheses are faulty not by plucking new ones out of the air and telling everyone you've found the Hoy Grail and you lot had better shut up and just believe it!
On your specific point about 30-year periods of rapid warming interspersed with 30-year pauses, this from Wood for Trees tells a slightly different story depending on whether you choose to accept the argument that the earth is still recovering to some extent from the LIA.
[If you don't like my dates, incidentally, I'm sorry but since I started this lark I have always used HadCRUT 3 and 80/10/40/70/00 to avoid accusations of cherry-picking. Except when I only need data from the satellite era when I use UAH, mainly because I trust the satellites more than I trust any figures that Jones or Hansen have had their fingers on.)
Two of the periods you describe as pauses are declines and the current one still has at least 10-15 years to go. Assuming no more than a continued hiatus that will mean a warming of around 0.7C (I'm eyeballing) in 150 years. Am I worried? No. Should I be? Not that I can see.
Looks like certain people from Pennsylvania are being more brazen than ever... perhaps a trial balloon for the return of the hockey stickhttp://mobile.nytimes.com/2014/01/19/opinion/sunday/if-you-see-something-say-something.html?_r=0&referrer=
David Chorley
I hope you washed your hands after posting that link. :-)
Mike Jackson
I like that graph. HadCrut3 under-reads slightly, but not enough to matter. The differences between the different datasets are small over multi-decadal periods.
The warming periods are similar. The three "pauses" show a trend. The earliest declined at 0.07C/decade. The second declined at 0.02C/decade. The most recent was about flat. If that trend continues the next "pause" may be warming. Are we seeing accelerating warming?
Your 0.7C in 2030 is not frightening., but is, alas, probably not the end of the story.
Sandy S
Reducing the uncertainty is what a lot of research in this field is about. The better the understanding, the better our chances of getting accurate forecasts, which would in turn make life easier for the decision makers.
Entropic man (Jan 19, 2014 at 1:42 AM) said “Perhaps I am reading more into this than you intended.”
You are… as I said “it’s rather unwise to try and extract too much detail from such a crude analysis” so I don’t think it worth digging deeper on these points in this particular thread.
Repeating what I wrote before, the evidence does not support CAGW if, as the Nature article suggests, the PDO is assumed to have contributed to historic temperature trends. This means that even if your statement is true (i.e. that the next warming period will resume in 2030 and "no warming for 17 years" is evidence that global warming is right on schedule), it will only serve to falsify the ‘enhanced’ greenhouse effect and so remove the ‘C’ from CAGW.
Entropic man, think of added CO2 as retarding cooling. As we add more the average ability to cool decreases, but amount of the decrease depends on weather. A lot of modelers depict weather as a positive feedback, for example: http://www.cgd.ucar.edu/cas/jyin/IPCC_paper_GRL_Jeff_Yin_final.pdf or more recently by the eminent scientists at the Guardian; http://www.theguardian.com/environment/2013/dec/31/planet-will-warm-4c-2100-climate
But the fact of 17 years of weather feedback leading to less than 0.1C per decade of warming (I prefer to use UAH satellite data as an index) with largely "neutral" weather is strong evidence for 1C rather than 4C for 2100. The weather is what determines the quantity of the positive (or negative) feedback to CO2 warming. for example with less concentrated convection there will be more warming on average (as postulate by the Guardian paper). Another example is decreased meridional heat flux shown by most climate models leading to more warming. That also means, incidentally, less storminess, cold snaps, etc.
The "11 year" solar cycle you refer to is a straw man. The warming from CO2 is allegedly delayed by decades due to ocean thermal inertia. If that is true, then a decadal solar cycle will be largely smoothed, and the upcoming cooling from low solar activity http://www.leif.org/research/Ap-1844-now.png will also be delayed by a decade or two. That graph plus a delay would also explain why warming is still continuing to some extent after the abnormally high solar activity of the 20th century tapered of in the 1990's.
David Salt
We don't have much data on the behaviour of the PDO over centuries, so it's contribution on the largest scales must be speculation.
Over the 130 years for which we have good data, the PDO is modulating the rate of warming in the short term, but not contributing to the longer term trend.The problem for your hypothesis that the two cycles between the 1880 and 2002 peaks there has been a warming of about 0.77C which cannot be assigned to the PDO.
This is conventionally assigned mostly to CO2. How much of it is due directly to the gas, and how much to enhancement remains open, subject to the behaviour of other parts of the system
Eric (sceptic)
"Think of added CO2 as retarding cooling."
A good description. The decrease in action with repeated doublings is natural logarithmic. If we were talking about a change from 0.04% to 4%, perhaps eight doubling, later doubling would poduce considerably less change than the early ones.
Over the likely range of change, a couple of doublings at most, the change would be effectively linear.
17 years is too short a period to draw conclusions about long term trends.
The Sherwood paper was about convection and cloud formation. He discovered that models with convection patterns which produced a greater proportion of high cloud (and hence more warming), were also better predictors of real conditions. He also noticed that the more accurate models predicted higher climate sensitivity.
Both weather and solar cycles are straw men where long term climate trends are concerned. They take place too briefly and do not input enough energy to overcome the thermal inertia in ice and oceans.
"They take place too briefly and do not input enough energy to overcome the thermal inertia in ice and oceans."
EM - please can you explain what this means?
EM, the weather patterns may change with CO2 warming, so weather is not a straw man but an unknown. My first link above is a very common result of climate models, even those that show more meridional flow in the short term. The long term shows a poleward migration of the mid latitude storm track, a strengthening polar jet and less meridional flow. That means less poleward heat flux especially in winter when the jet currently migrates south.
If the weather patterns do indeed change like that, the lack of distribution of warm air to polar regions in winter will mean less heat loss for the planet as a whole.
As for the straw man potential of solar cycles, yes there is some, particularly 11 year cycles as I mentioned. But nobody can predict what the sun will do over the next few decades. A lull in activity spanning several cycles is not out of the question. It is simply an unknown. Such a lull in activity would not just lower TSI a bit, but would change weather patterns over the span of the lull. That change may include more meridional flow due to reduced solar UV and or increased cosmic rays.
In short the cooling potential of more meridional flow and thus more polar heat flux cannot be ignored when considering the next few decades of global warming (i.e. reduced cooling). It may offset some or all of it.
not banned yet
I would think you'd know.
There are four main parts to the climate system; land, atmosphere , ice and ocean. Each can store energy. Add more heat and you increase their temperatures.
Each has a different specific heat, the amount of heat they store for a 1C temperature increase.
Compared to the others the atmosphere has a low specific heat and a low mass. Add a small amount of heat and you get a big temperature change. Hence the big temperature changes seen even during one day. The atmosphere reacts quickly to short term changes in energy.
The ocean is the opposite. It has a large volume and a high specific heat. You have to pump in a very large amount of heat to get even a very small temperature change. You see this as the seasons change, with sea surface temperatures lagging months behind land temperatures.
The average temperature of the whole system depends on the amount of energy entering the whole system. Given a few centuries of stability the whole system comes to equilibrium as the different parts exchange heat. Put in more energy and the whole system gradually comes to a new equilibrium at a higher temperature.
You upset that equilibrium by increaing the amount of incoming energy; eg by increasing CO2 and its greenhouse effect. The atmosphere reacts in hours.The ocean surface reacts in months. The deep ocean reacts over decades or centuries.
Weather varies over hours or days. The atmosphere warms or cools over that timescale. You observe big changes in air temperature and small changes in sea surface temperature.
Solar cycles change insolation by a small amount over a decade. There is time for the atmosphere and sea surface to react, which is why they are visible in the record, but not for enough energy to reach the deep ocean, which does not change.
Long term increases in energy such as the orbital changes inducing the end of a glacial period produce a sustained increase in energy input over centuries. This gradually warms the deep ocean and allows the whole system to come to a warmer equilibrium.
The PDO and cAGW are intermediate. The PDO undergos "cool" 30 year periods in which the Pacific is a net absorber of heat to depth, leaving less to heat the air and sea surface. Temperature records show a pause. The "warm" 30 year periods bring that energy back to the surface. Incoming energy stays in the atmosphere. Air temperatures rise.
Increased CO2 is warming the atmosphere enough to allow increased heat flow into the deep ocean in the same way, very gradually warming the whole ocean volume. It will take decades/ centuries to warm the whole ocean volume.
Eric (sceptic)
The unknowns you mention are all short term and hard to predict, which is why short term forecasts for a few years or a decade ahead are less certain. Longer range forecasts, in which these short term variations have had time to average out, are more reliable.
As for meridional flow, this is increasing in the Antarctic, possibly due to changes in the Ozone hole.
In the Arctic the amount of heat flowing into the Arctic Ocean is incresing, not decreasing. At present the interactions involving the Arctic Oscillation, the Atlantic and Pacific, and the jetstream are too complex and unstable to say much about meridional airflow.
"Long term increases in energy such as the orbital changes inducing the end of a glacial period produce a sustained increase in energy input over centuries. This gradually warms the deep ocean and allows the whole system to come to a warmer equilibrium."
EM, don't forget that there are positive feedbacks to warming from lowered albedo and lower dust along with the higher CO2 released from the warmer ocean. Those feedbacks are nonlinear particularly albedo as the NH glaciers melt. The energy change from the orbital changes are not as important as the incidence angle and weather changes.
That last one is the one you keep leaving out of your analysis. You are correct that it is complex and we can't say much about it right at the moment. But there is evidence that the transition from glacial to interglacial conditions involved a rather large weather feedback from poleward movement of the polar jet and storm tracks. Here's one description: http://asmerom.unm.edu/Research/Papers/Asmerom%20et%20al%20Nature%20Geo%20SW%20Winter%20Moisture%20Last%20Glacial.pdf
Here's the URL for that paper in a format that might work: http://tinyurl.com/ogkevs7
Entropic Man
No arguing with that, although forecasts currently have the authority of certainty rather than being best guesses. In my children's lifetime my best guess is that climate forecasts will remain best guesses.
It still doesn't answer the question of why this is not just another peak in a series of peaks in descending magnitude.
EM - Re: GISP ice core temperature, Current Interglacial
If you are so certain that the 20th rise is due to anthropological CO2 emissions, please explain what caused the following rises, which are all similar if not larger in magnitude: GISP ice core temperature, Current Interglacial
The Medieval Warm Period peak (800-1300AD)
The Roman WP - 500BC - 100AD.
The Bronze/Iron Age WP - 1500BC to 1000BC
The Minoan WP - 2500BC to 2000BC
and the two Holocene Optima circa 6500BC and 5000BC respectively?
And please don't say these temperature rises are just unique to Greenland - they show up in other proxies, and in the Vostok cores also - as noise, in a downward trend:
Enjoy the Holocene while it lasts.
Sandy S, lapogus
You need to get things in the right order. Weather is the effect of climate, not its cause.
Tak a look at Figure 1B here.
http://content.csbs.utah.edu/~mli/Economics%207004/Marcott_Global%20Temperature%20Reconstructed.pdf
This is the temperatures for the last 11,000 years based on an ensemble of 70 proxy studies, including the data Lappus used for his graph and including confidence limits. The overall pattern shows a sustained warmth anomaly around 0.4C from 10,000 to 5000BP, then a gradual decline accelerating downwards from about 1000BP, This bottoms out about 150BP at -0.4C. From there the data bcomes unreliable as most proxies stop. The evidence for the subsequent warming has to come from the temperature record. Marcott et al recognised this, but carried the graph forward until they ran out of proxies around 1940. This uptick is what got all the spin-sceptics all het up, but its not relevant to our discussion.
Note that the short term peaks you discuss disappear when you go from one proxy to an ensemble. This strongly suggests that the big changes in the Lappus graph are local variations, noise on the longer term trend shown by Marcot et al.
What distinguishes the 20th century warming is that it abruptly reverses the 5000 year downwards trend, for no detectable natural reason. If you look at Figure 2 in the paper you see the main forcings driving long term temperatures. Look particularly at 2F and G, the solstice effects, which are driven by orbital changes. They are the main driver of the cooling trend, and do not change as we enter the period of 20th century warming.
With no natural change in forcing to explain the warming, we are left with CO2, which is sufficient.