When paleoclimatologists met in 1972 to discuss how and when the present warm climate would end, termination seemed imminent and it was expected that rapid cooling would lead to the coming ice age.
These ideas were based on the 1M year analogue for climate transitions first proposed by M Milankovitch over 60 years ago which has been demonstrated to show the correlation of glacial and interglacial climate with solar insolation as it is modulated by our changing distance from the sun.
These data may be used to serve as a signal for the coming ice age.
Orbital geometry was approaching similar conditions to those of the previous transitions to ice.
But soon it was observed that global temperature was increasing and at about this time Global Climate Modeling (GCM) received more attention and the Milankovitch analogue was forgotten. There has been little further discussion about the coming ice age.
Perhaps underwriting the idea that our consumption of carbon and production of CO2 was contributing to climate warming was the work of Loutre and Berger and a paper by Loutre in 2000 claimed that the Holocene (the current warm period) would extend for at least another 30,000 (KY) years because of the effect of CO2 concentration as a greenhouse gas.
It was acknowledged in this paper that the orbital geometry 400KY which featured muted amplitude, was the “best and closest analogue to our near future climate”, but inexplicably the Global Climate Model LLN2-D NH was “tuned” to replicate the past 200KY climate transitions when insolation amplitude was at it’s highest level over the 400KY cycle and quite unlike present conditions. Using different values for CO2 it was found that “best agreement with SPECMAP is obtained near 210 ppmv CO2 ”.
Then using a modeled Holocene they projected climate using a range of CO2 forcing, and they reported that there was no transition to ice for at least 30KY into the future.
The algorithm for this process is not disclosed but the authors rightly list the limitations of the model in which CO2 is considered as an external forcing i.e. the carbon cycle is not simulated by the model. Clouds and the hydrological cycle are simplified and so is the heat transport to middle and deep ocean. In addition regional changes such as the North Atlantic and over Europe are not simulated “and might depart from the global trend”.
It is unfortunate that these limitations appear to have been ignored and the AGW hypothesis was born and has occupied science and the media ever since.
The Milankovich analogue has been forgotten.
But the reality is that CO2 is not driving temperature up , in fact the data below suggests that global temperature may be cooling since 1998 and CO2 continues to climb.
Remote Sensing Systems Advanced Microwave Sounding Units. Satellite Temperature data analysis here: http://wattsupwiththat.wordpress.com/2008/03/10/feb-2008-rss-global-temperature-anomaly-near-zero-and-in-good-agreement-with-uah/
There is further detailed material in a paper by Dr Willie Soon which shows that there is no evidence to support global warming by CO2.
The concentration of CO2 varies according to the temperature of the ocean and CO2 follows temperature. If the present decline in temperature continues we can expect to see a decline in the rate of CO2 as more is dissolved in a cooler sea.
The climate trends during the Holocene, and also the regular sudden climate transitions between the ice ages and the interglacial climate over the past 1M years are better explained by reference to the great external driver, the Sun.
There is abundant archeological evidence to show that global temperature is closely correlated with solar activity.
The following chart shows how solar activity has correlated with climate during the Holocene. The data is based on analysis of Carbon 14 which varies in concentration according to the level of solar activity.
Solar activity over the past 70 years has been greatest for 8000 years and is the most likely cause of the recent temperature trend through 1998 that has been wrongly attributed to CO2 warming.
The evidence for the solar insolation signal for the ice ages is contained in the Milankovitch analogue which has been overlooked for many years.
The following data was compiled by the mathematicians Quinn and Levine (Quinn et al 1991, A 3 Million year Integration of Earths Orbit, The Astronomical Journal Vol 101 pp 2287-2305). Insolation values due to Precession, Obliquity and Eccentricity as well as total insolation or Solar Forcing are charted on the same time scale as Stages of Glaciation representing climate. This climate data was provided by Lisieckie and Raymo and is based on sediment proxies. The climate data shows close agreement with Ice core data based on a different proxy.
This chart confirms the correlation of climate transitions with insolation which is modulated by earth's position in orbit and was first proposed by Milutin Milankovitch over 60 years ago.
Milankovich Analogue Data, from Quinn et al. 1991
The signal for each transition to ice can be found by careful inspection of the data and projections.
In studying the analogue there is no use of a GCM (general circulation model) which is subject to limitations and interpretation. Use of the analogue is based on simple observation of clear empirical data and the archeological record of temperature. The data and the correlation are sound.
The interglacial stages are shaded grey by the authors, and the glacial stages are clear.
By reference to this chart we can make the following observations:
* Every interglacial (shaded grey) survives for a single half cycle maximum in Solar Forcing or total insolation, (yellow) and expires when insolation is in rapid decline and we are near that position now. The interglacials at 200 and 600KY are split because Precession (red) and Obliquity (green) combine in opposite phase to defeat Eccentricity and the interglacial temporarily returns to ice. Conversely total insolation at 400KY is forced into a second half cycle and the interglacial is extended to 28,000 years. Because muted Eccentricity at 400KY is considered a precedent for present conditions, the 28KY interglacial has been widely misreported as evidence for an extended Holocene. From the data we can see we have no such additional insolation half cycle. Insolation now is in rapid decline from a single peak.
* Each of the “Ice Ages” over the past 1M years corresponds with the minimum half cycle of Eccentricity (blue) which is the predominant orbital factor. We are close to the eccentricity half cycle minimum now.
* Counter intuitively every transition occurs from peak global T ;We may have a decline in T since a peak in 1998 .
* It follows that every transition occurs when polar ice melt has peaked. We have ice rebuilding in some regions now.
* Last transition to ice occurred about 120KY ago when T was 5 degC hotter than now and polar ice melt was greater than now. The average cycle is 100KY and the coming transition is overdue.
* By inspection we can see that all of the transitions have occurred when Solar Forcing ie total Insolation was very close to the present level.
* In addititon to the above which relates to the Milankovitch cycles we have a coincident decline in solar activity.
Solar activity is dormant now and cycle 24 is delayed.
The variations in Insolation seen in the data are not sufficient alone to explain the sudden climate transitions from interglacial to ice and reverse. The data provides a template for timing the changes based on the extended correlation but there must be an internal mechanism to explain the rapid process.
At the tipping point for each transition, global T has peaked. This follows from the fact that Earth has been receiving peak insolation throughout the interglacial for about 10,000 years. Polar ice melt has peaked and the polar seas are freshened which may affect circulation of the MOC and interrupt heat exchange with the equator leading to sudden NH cooling.
In addition it has been proposed by William Kininmonth, meteorologist and former head of Australia’s National Climate centre, that atmospheric heat and humidity transport to the NH would offer a larger contribution to variations in heat budget if it could be shown to respond to the 100KY cycle.
I think that this factor which is driven by equatorial SST will indeed have a 100KY signature because the transitions correspond to T max. which follows the 100KY cycle. SST will also peak near T max in accordance with the 100KY cycle.
This proposal offers the further advantage that it would provide a faster response which helps to explain the rapid climate change observed in the transitions.
It is significant to note that at this tipping point, energy transport to the northern hemisphere is at a peak and there is abundant humidity transported to the NH at a critical time when insolation is in rapid decline.
These are the conditions which favour maximum precipitation in the northern hemisphere winter.
These are the conditions now.
I think that the rapid decline to ice conditions will occur by the following process:
As temprature declines the precipitation will increasingly be snow and as albedo increases more heat will be reflected. Initially cloud cover will insulate the snow from summer insolation. Insolation continues to decline.
As temperature further declines water vapour in the northern hemisphere will be reduced and at T zero deg C it will practically disappear leading to a sudden elimination of water vapour GHG .
Then positive feedback due to this process will lead to a rapidly widening region of sub zero T and glaciation will begin to expand.
There will be a decrease in cloud cover allowing more heat to escape in winter.
In this way the sudden transition to ice has commenced.
The geological record shows that the transitions are sudden, long term and extreme.
All of the Milankovitch parameters for a transition are satisfied by the present orbital position. We have already seen extreme northern hemisphere winter conditions and temperature appears to be declining in the short term. The decline will continue under rapidly declining insolation and the coincident effect of reduced solar activity which has also been correlated with temperature in the past.
It is possible that we may have already entered the sudden stage of the transition.
I would challenge: is there a good reason why the analogue will not apply now?
It is overdue time for engineers and scientists to reconsider the Milankovitch analogue and to plan for the contingency of an imminent transition to ice.
I think that the AGW hypothesis has proven to be a costly diversion of resources .
Peter Harris
Retired Engineer
luke,
I have been travelling.
Sorry to hear that you have not progressed one iota.
Maybe you should read the article again.
It is really very very simple
1.Milankovich proposed that climate transitions were timed by orbital variations which affect insolation in a cyclic predictable pattern. With laborious calculations he proved his hypothesis which was accepted. More recent data by Quinn et al confirms the relationship between the ice ages and orbital geometry as proposed by Milankovich.
2. It remains for you to inspect the data and find similarities now with the orbital parameters when each of the previous interglacials made sudden transition to ice and that is explained in my article.
You seem to be insisting that there should be some evidence to be found in TOA radiation but I expect this to pattern Qinns insolation data further modulated by solar activity. There will be no sudden major decline at TOA. The reality is that we do not know or understand the process that will cause the interglacial to collapse and that is why I wrote the article. I have suggested changes in state of H2O leading to a transition from interglacial to glacial.
You keep referring to Hollan and his claim that insolation will be too high for a transition in the forecast period but as I have explained before he has overlooked the fact that the transitions have occurred well before minimum at levels similar to now.
Peter
We would face a much greater disaster with a new ice age than with global warming. There is no experimental data to support the hypothesis that increases in human hydrocarbon use or other greenhouse gases are causing or can be expected to cause any global warming. Predictions of global warming are based only on computer models which do not hold up to honest scientific analysis. There is no provable evedence of a coorelation between increased Co2 and warming. Of many scientific papers on this topic one of the best; www:jpands.org/vol12no3/robinson600pdf. The ecconomies of both Australia and Europe are rapidly being destroyed by buying in to the greatest scam ever which will destroy civilization as we know it. Proof? Just read some of the blogs in these countries.
Jeez Peter
(1) you have no idea of the accuracy of the Milankovitch stuff at a decadal or even centennial level. You could be out by 100 years and not know.
Zilch. If so - table it with some dates. Actually where are we today in terms of distance to the trough or peak - how many days Peter ?
This business of "no tolerance" is totally spurious.
(2) and we're going to have a change in insolation and the radiation at the top of the atmosphere will be unchanged will it?
(3) the regularity of past cycles is no guide to the future as Hollan has shown
Really ...
If you're going to drop references a url link would be good.
I don't think we've progressed on iota.
Dear Lance,
I am not comfortable with your hypothesis about the very recent arrival of the Moon in Earth orbit and I have seen your evidential chart based on a dramtic change seen in the rate of T variations as we emerged from the last ice age.
I believe that the rapid and dramatic changes in T observed during the glacial phase are an unexplained characteristic of each of the ice ages.
We have two different relatively stable stages of quite different climate equilibrium ie glacial and interglacial. However the glacial phase is characterised by these rapid changes in T.These changes have been referred as Dansgaard Oescher events and are most evident in the NH.
The processes behind the T variations are not understood although closely related to Heinrich events which correlate with interruption to the MOC. Bond et al showed evidence that the Dansgaard Oescher evemts were globally synchronous.
Changes in albedo are thought to play a role.
I think that there should be more work done to understand the role of cloud cover which can instantaneously make dramatic changes to heat reflection or entrapment.
Rahmsdorf (Potsdam 2003) observed a 1470 year cycle in these T variations but could not find a matching Lunar cycle.The regularity of the cycle suggests an inter planetary beat.
I agree with your comment that we should consider all of the Solar influences which are modulated by distance including gravity, and recent work by Russians Troshichev (2005) have also shown a correlation between the Interplanetary Magnetic Force with extreme Antarctic winds which affect the Lan Nina/ El Nino systems.
I think the Earth sciences have been neglected with the obsession to simulate by GCM and it seems that there is little exploratory thinking in this neglected field.
Lance beware of the wiles of Jennifer or you too could be sucked into a blogging.
Regards
Peter
Alarmist creep aka Luke
Your references to the measured solar data by ACRIM and other means are irrelevent as I have explained before.
My article is about the Milankovich analogue which shows that the climate transitions correlate with CALCULATED insolation based on orbital position and it shows that sudden transitions to ice have ocurred EVERY time when orbital parameters are similar to now. Based only on the 1M year record we can say with 100% certainty the there will be a transition to ice whenever Eccentricity approaches a minmimum.
It is approaching a minimum now.
The interglacials survive only one positive half cycle of Solar Forcing.
We are near that position now.
I have challenged anyone to explain why the transition will NOT occur this time.
Only Prof Lance Endersbee has offered a reason which would cancel the Milankovich analogue if he is right about the recent arrival of the Moon in Earth orbit but that hypotheis is the subject of a friendly argument.
The insolation data calculated by Quinn et al was confirmed in detail by Laskar. There is no tolerance given.
The transition will be rapid. The process is not known and is not even being studied as most scientific resources are now devoted to GCM simulation funded to investigate GW. The transition cannot be simulated as the process is not known.
I will be travelling for a month and will only be able to respond periodically.
Peter
Yes, we are most certainly entering uncharted territory, but there are basic principles still being ovlerlooked. Ultramicroparticular pollution in the upper atmosphere that doesn't resemble anything volcanic, has to be brought into the newer models. There may be evidence for a decrease in temp. over say 10ky, but the exponential effect of light scattering in the troposphere could potentially accelerate this cooling. By how much you may well ask???
from Lance Endersbee
I want to caution against suggestions that the predicted cooling of the
earth may lead to a return to the Ice Ages.
It is evident that the present dynamic system driving climate is radically
different to that of the recent ice ages.
I attach a chart of temperature changes for last 50,000 years.
It is taken from the excellent paper by Bob to AusIMM last year, also
attached.
Note the dramatic drop in the range of the variations in temperature which
occurred about 10,000 years ago.
In my book I explain that the dramatic change was due to the acquisition of
the moon into orbit around the earth.
Prior to the capture into orbit around the earth, the moon had been captured
by the earth into synchronous orbit around the sun.
During the Ice Ages, the dynamic system driving climate was the sun, earth,
other planets and the cosmos.
For the past 10,000 years, the dynamic system has been all of these plus the
moon.
I describe the evidence for this in my book.
The capture of the moon caused a great increase in diurnal tides, and
created the Gulf Stream.
It modified geotectonic activity.
It certainly modified climate.
During the ice ages, the climate changes relate well to the Malenkovich
cycles.
Malenkovich was interested in variations in solar radiation.
But the solar radiation cycles are also an indicator of variations in
gravitational attraction.
Thus the Malenkovich cycles can also be used for gravity variations, and for
geotectonic analyses.
I think gravity effects are evident in the stick-slip behavior during the
ice ages.
The record suggests a gradual accumulation of strain with major geotectonic
convulsions at 100k intervals.
With the capture of the moon into orbit the geotectonic response of the
earth was modified.
The much stronger lunar tides led to more frequent and smaller geotectonic
events.
Thus the Malenkovich cycles are still with us, but the impact is modified.
There is wonderful historical evidence about the capture of the moon.
The ancient Greeks had a word for their early predecessors- they were the
people before the moon.