Discussion > Are Geological Paleo-Climate Records Relevant to The Climate Debate?
Okay, Philomena. Now, point to where I, or anyone else on this site, have said that there has been no warming since the end of the Little Ice Age. I am not sure if you have ever been hill-walking, but one of the remarkable things that you would notice is that, once you are at the top of a hill, you tend to be higher than anywhere else in the immediate vicinity. This does not mean that you are higher than anywhere else, just the immediate vicinity. If you are on a plateau, then your path might well continue higher but, to that point, you are higher than you have ever been on that walk. While it might surprise you, I do hope that the warming continues; to date, it has brought us great benefits, certainly more benefits than a cooling would do.
Radical Rodent
Radical Rodent
I never know how high to pitch to you. One moment you come across as intelligent and well educated. Then you come out with something monumentally stupid.
This is the sort of dumb question I mean. Read back over my comments on energy .imbalance and you will find that the two statements are not exclusive. I mentioned that in the short term the imbalance varies with snowfall , weather systems, sunspots etc. Over a few years you see variation due to ENSO.
Over 5000 years the short term noise cancels out and you can see the long term temperature trend. This is my data at 20 year resolution.
You pose a paradox. You claim that there is no data, yet you list four different climatic periods.When were all these warm periods, how much did their temperatures vary from the long term trend? We're they stable or transient?
I have shown you the method. Since you know these periods, you now have the chance to work out the energy imbalances. I would be interested to know if any of them approach the 0.7W/m^2 we see now.
This is GISTEMP since 1970,with the long term trend and the approximate confidence limits. I have also included the post-1998 trend. The difference between the two trends is small and getting smaller. If you genuinely see an ongoing pause, could you explain how you infer it.. I see nothing.
Entropic man
PC: mind you, referring to the past month and my own experience, I doubt that it was as warm as that we, in the UK, enjoyed in 2012, a March heat-wave that the BBC presaged with great glee was bound to lead to droughts and oppressive temperatures later that year. While I know that you will dismiss this as a mere local event, but, as far as most people are concerned, local events are what really concerns them.
Radical Rodent
EM: perhaps I am just dumb, but then the evidence does show that I might not be quite as dumb as you are. What paradox? The data I referred to that you do not have is the data to determine what the average energy imbalances might have been during or between the periods I stated. There is strong evidence that there was a Roman Warm Period (when the temperatures may have been up to 2K warmer than today), that there was a Dark Ages, that there was a Mediaeval Warm Period (when the temperatures may have been up to 1K warmer than today), and that there was a Little Ice Age. Would you like to dispute any or all of those periods?
If – and it does seem a big, big IF, with you – these did exist, then there must have been a transition between the two when the average energy imbalance was greatly different from the average you have surmised over several thousand years. What, during these various transitions, was the extrapolated century averaged energy imbalances for any 3 or 4 decades you might select?
Radical Rodent
Radical Rodent
There is strong evidence that there was a Roman Warm Period (when the temperatures may have been up to 2K warmer than today), that there was a Dark Ages, that there was a Mediaeval Warm Period (when the temperatures may have been up to 1K warmer than today), and that there was a Little Ice Age.
If there is no data, there is no data – you cannot just make it up!
Two contradictory statements. If there is no data how do you know that the Roman Warm Period was 2C warmer and the Mediaeval Warm Period was 1C warmer? What is this strong evidence?
I eagerly await your energy imbalance calculations.
Entropic man
Whoa, there… person. You are constructing a strawman here, I suspect: while there is strong data pointing to the facts of the warm periods and intervening cooler periods mentioned, there is not the data to be able to construct average energy imbalances in the short time periods from then that you are working in, in the present, but there might be sufficient for you to construct long-term averages. You dismiss peaks in the average in historical records as “noise”; why is that average in the present not similar “noise”?
So, I'll ask again: what is the average energy imbalance over the past 2,000 years?
Radical Rodent
EM
"Over the 5000 years before 1850 there was a 1C cooling. That is 0.02C/ century and a cooling imbalance of 0.02W/^2"
Please provide the data you rely on to support the cooling imbalance you quote above assertion (NOT Marcott. )
The COHAP simulation shows a decline in summer ( June ,July, August) radiation receipts from 108% of present insolation 10ka ago to 0% at present but an INCREASE in winter ( December, January, February) insolation of an equal amount over the same period. This is attributed to a particular combination of orbital conditions; see Kutzbach and Webb ( 1993).
PS The claimed resolution of Marcott is 300 years - not 20 years.
Paleoclimate Buff
Paleo,
The questions that was originally posed was why planetary energy imbalances of 0.6W/m^2, or so, aren't the norm. The very simply answer is that - given the heat capacity of our climate system - if such energy imbalances were the norm we'd expect to see evidence for century-scale variability of magnitude 1K, or greater. Given that there appears to be little evidence of variability of this magnitude over the last few thousand years, energy imbalances of 0.6W/m^2 appear not to be the norm. Even the warming associated with the Milankovitch cycles appear to be slower than this (i.e., about 4-5K over a few thousand years).
...and Then There's Physics
Paleoclimate buff
I think you mean COHMAP. That data is 23 years old and based largely on stratigraphic pollen analysis As an old pollen analyst myself it was nice to see, but there should be better data by now.
Can you translate that 8% into temperatures? An 8% insolation reduction globally would produce 28C cooling, which is absurd. How big a temperature change are you actually talking about?
The source I linked the graph from, Tamino said "20 year resolution". Note that the graph uses the RegEM rconstruction, not the usual Marcott et al(2013) presentaion. Anyway, the resolution does not matter in this case as we are discussing a change over 5000 years.
Entropic man
aTTP
"we'd expect to see evidence for century-scale variability of magnitude 1K, or greater........... there appears to be little evidence of variability of this magnitude over the last few thousand years,"
dO18 ratios recorded in the last 11,500 years show at least five episodes where temperature changes of the order of 1ºC occurred within periods of the order of a century - NORTHGRIP (2004). World data Center for Paleoclimatology, NOAA Climatology Program.
Clearly it is extremely difficult to produce definitive evidence of such minor temperature fluctuations over such brief periods as a century which may have occurred in pre instrumental times and dogmatic statements that such fluctuations have or have not occurred (and when ) are not justified by the present state of knowledge.
However there are significant research reports which indicate that changes of this scale over centennial times scales have likely occurred on multiple occasions in the Holocene.
See:-
Dansgaard (1989); Atkinson ( 1987); Koc et al.( 1994); Klikgaard-Kristensen et al. ( 1998); Baillie & Munro (1988); Alley et al. ( 1993);
Paleoclimate Buff
Radical Rodent
I ask again What strong evidence? If it is too weak to infer temperatures, how can it be "strong"?
So, I'll ask again: what is the average energy imbalance over the past 2,000 years?
Are you really incapable of doing this for yourself? I am getting tired of doing your thinking for you,
Let's do in in terms that even one of my duller 4th corners might understand. Since you were unable to give me any of your strong figures I will stick with the data I have.
2000 years ago was 16AD. For the 1834 years to 1850 the cooling imbalance imbalance averaged 0.02W/m2.
For the 70 years to 1910 the temperatures were approximately constant, therefore the imbalance was close to zero.
Between 1910 and 1970 the warming imbalance averaged 0.4W
From 1970 to 2016 the warming imbalance has averaged 0.8W/m^2.
An average is (sum x)/n.
The calculation is therefore (1834*-0.02)+(70*0)+(60*0.4)+(46*0.8) / 2000 = 0.012W/m2
At this point you will of course be tempted to point out the usual denier thinking that an average imbalance of 0.012W/m2 over 2000 years is nothing to worry about. Please don't. As even you would agree, we have seen a long slow cooling, followed by rapid warming.
Entropic man
Paleoclimate buff
Please provide links for your papers. is the HTML protocol to use.
I gave up an attempt to reply to one of your previous posts after a long and unproductive literature search.
Entropic man
Paleoclimate buff
As you see, the problem with trying to describe HTML protocols is that they tend to activate and disappear. Look below your reply box for more information. Failing that, one of the IT experts here might help.
Entropic man
Paleo,
Well, 5 in 115 centuries is still not "the norm". However, I've looked at NorthGRIP (2004) and I don't see the 5 events in the last 11500 years. Maybe you could clarify where I could find this information. Also, NorthGRIP - I think - is a single ice core, so unlikely to be representative of the entire globe.
...and Then There's Physics
Sorry, aTTP, that was not the question. Close, and close enough to make it look a stupid question; how convenient. The original question was: what evidence is there that a planetary energy imbalance is not the norm? No numbers involved, as even I can accept that there is not necessarily any balance in an imbalance. The evidence does suggest that perpetual energy imbalance is the case, as there are precious few periods in history or prehistory when the energy content of the planet was not either rising or falling (recently, geologically-speaking, we have been either going into an ice age, or coming out of one). Obviously, we can only interpret long-term rises and falls with periods further back than reliable instrumentation; this might mean that energy imbalances as great as, or even greater than, what we are experiencing today might be hidden in the broad brush-strokes of palæoclimatology. I could quote palæoclimatologists who state that a century-scale variability of 1K is not unusual, but am pretty certain that you will find some reason to dismiss them (as you have with Palæoclimate Buff, above). While this might not have been obvious over the past few thousand years, most palæoclimatologists admit that this period has been unusually stable, so, perhaps Mother Earth is reverting to her normal behaviour. Then again, I have seen data showing that the drop of >1K into the Little Ice Age occurred over just a few decades. Ho-hum.
Entropic man: what am I denying, for you to claim “the usual denier thinking”? I merely asked you for the average energy imbalance since 16AD; for some reason, you then proceed to give me the average energy imbalance since 1834, which works out at an unremarkable 0.012W/m2 over 2,000 years, despite you calculating it with data spanning less than 200 years. All records show that the temperatures in 16AD were most likely warmer than today; some claim up to 2K, others say not as much. I would moot that the average figure is a negative, which would explain why you are so loath to admit it. We do not have the data to be able to calculate a figure for any few decades in the warming period from the Dark Ages to the Mediaeval Warm Period, but I would posit that it is possible that there could have been times when the average energy imbalance was as high as it is claimed, today, say, in the 800s.
Radical Rodent
RR,
what evidence is there that a planetary energy imbalance is not the norm?
If you mean, what evidence is there that it is not normally zero, then none, because it is almost certainly is not normally zero. That is a stupid question and I assumed that it was not what you were actually asking. There is, however, little evidence that the norm is a planetary energy imbalance comparable to what we have today. I wasn't trying to make your question seemed stupid as it seemed like a reasonable question. It appears that I may have misunderstood and that you were actually asking a stupid question.
...and Then There's Physics
Not a stupid question, aTTP, as you have been banging on about planetary energy imbalance as if it was something unusual. I merely wanted to know why, given that it is widely accepted that there has been constant change in the planetary energy balance, why you seem so fixated that the present imbalance is unusual.
Radical Rodent
RR,
Not a stupid question, aTTP, as you have been banging on about planetary energy imbalance as if it was something unusual.
I've been banging on about it because it is a pretty fundamental aspect of AGW. That you appear not to realise this is not a surprise.
I merely wanted to know why, given that it is widely accepted that there has been constant change in the planetary energy balance, why you seem so fixated that the present imbalance is unusual.
Because it is probably about an order of magnitude larger than has been the norm for the last few thousand years. Why could this be? Maybe - and this is just a thought - it's a consequence of us pumping many giga-tonnes of radiatively active gases into the atmosphere. Actually, yes, that probably is the reason, but you're free to deny that if you wish.
...and Then There's Physics
How can you be so confident that there has never been a period of a few decades in the past 11,500 years when the average energy imbalance was as great as you are reporting, now? Today, the energy imbalance could be as “noisy” as it was in, say the period 880AD – 910AD, or 1250BC – 1220BC, yet you seem convinced this could not be. Why?
Radical Rodent
RR,
I didn't say never. There probably has been a few decades in the last 11,500 years where the imbalance has been similar to today (internally driven warming of a few tenths of a degree per decade, for a few decades, is quite possible). However, there is little evidence to suggest that such a large imbalance is the norm, or even common, in the last few thousand years.
...and Then There's Physics
Radical Rodent
This is becoming embarassing. 16AD is 1834 years before 1850AD. I certainly did not start from 1834AD. Is the difference between --0.012 and 0.012 large enough to me to equivocate about? I think not. I ran the calculation again and the 0.012 is actually positive.
All records show that the temperatures in 16AD were most likely warmer than today; some claim up to 2K, others say not as much
You keep talking about your evidence, but you do not produce any.Links please. You may not be a scientist, but I still think like one. Peer reviewed scientific papers only, please. Try to give several sources which agree, rather than a single ice core in Greenland. Perhaps Paul Dennis and Alan Kendall can help.
I would posit that it is possible that there could have been times when the average energy imbalance was as high as it is claimed, today, say, in the 800s.
Again, where is your evidence? Another standard argument on the sceptic propaganda sites is that the Romans grew grapes in England and therefore it was warmer than today. They carefully ignore that there are English vineyards today, one as far north as Yorkshire. Show me numbers!
On second thoughts, perhaps you would prefer to change the subject. You have already demonstrated your foolishness to an astrophysicist and a retired science teacher, plus whoever else is lurking
Entropic man
Another standard argument on the sceptic propaganda sites is that the Romans grew grapes in England and therefore it was warmer than today. They carefully ignore that there are English vineyards today, one as far north as Yorkshire.While you carefully ignore that this is evidence that temperatures were either close to or exceeded those of today.
You obsession with numbers and this rather crazy demand that we supply only peer-reviewed papers as evidence that any student of historical documents can provide is starting to get tedious. We have ample evidence of warmer and cooler periods from those documents and the fact that they weren't able to calculate the world temperature to three decimal places does not make their evidence any less reliable just a little less accurate.
Unless you have managed to avoid reading any history at all during your life, you know this to be the case.
Their main priority of course was survival. It is only now that that is no longer a matter to which we need to give such high priority that we can afford to waste our time obsessing over minutiae.
Mike Jackson
EM dismisses a citation by Paleoclimate Buff on the grounds that it is 23 years old.
My understanding is that the warming effect of CO2 - extensively referred to by AGW enthusiasts as underpinning the greenhouse effect of CO2 relies on work by Fourier published in 1824 and Arrhenius published in 1889. Moreover the reconstruction of pre- industrial levels of atmospheric CO2 relies on work by Callendar published variously between 1938 and 1950 and the publication of Keeling in 1960.
Perhaps we should dismiss these on the same grounds.
Spectator
EM (2.17pm).
Why is it that periodically you feel the overwhelming need to insult those who are taking their precious time to communicate with you in an amicable fashion? It is unpleasant for the rest of us to watch.
Is it your time of the month?
Alan Kendall
And not exactly "shattered" either, RR. Phil-o-Clark links to a WUWT article which shows that some monthly temperatures are now slightly higher than they were in, errrmm, 1998. Should we be pleased, crying in our beer/milk, or just bored with the same-old-same-old.