Wikipedia says:
The Eemian was an interglacial period which began about 130,000 years ago and ended about 114,000 years ago. It was the second-to-latest interglacial period of the current Ice Age, the most recent being the Holocene which extends to the present day. The prevailing Eemian climate is believed to have been similar to that of the Holocene.
Last Interglacial Arctic Warmth Confirms Polar Amplification of Climate Change
by the Cape Last Interglacial Project Members
Guest summary by Peter Hodges of the Paper at:
http://chubasco.fis.ucm.es/~montoya/cape_lig_qsr_06.pdf
It is widely accepted that the last interglacial was much warmer than the current. Forests reached the Arctic ocean across most of Eurasia, Scandinavia was an Island due to higher sea levels, and hippos swam in the Thames. As a basic introduction to the subject the Wikipedia http://en.wikipedia.org/wiki/Eemian entry is well worth a quick read.
The paper concerned, however, offers a comprehensive survey of literature concerning the Eemian interglacial, focused on the Arctic. The literature cited by the authors consists almost entirely of data from actual empirical research as opposed to “data” from model outputs. There are also four pages of citations for anyone who wishes to check the authors sources, or simply dig deeper. For those who have time, I highly recommend reading the paper in its entirety.
For those don’t have the time, the authors offer a concise summary in their conclusion:
“Quantitative reconstructions of LIG (Last InterGlaciation) summer temperatures suggest that much of the Arctic was 5C warmer during the LIG than at present… Arctic sea ice was reduced to a greater extent in the LIG than during the early Holocene due to both greater summer insolation and the larger flux of relatively warm Atlantic surface water into the Arctic Ocean during the LIG than at any time in the Holocene.”
The fundamental factor which drove Eemian temperatures higher than those in the Holocene was dramatically higher summer insolation. Northern Hemisphere insolation during the Eemian was higher than today, while Southern Hemisphere summer insolation was lower than today. Most importantly, “By the time sea level reached present in the Holocene (6 ka), the high latitude Northern hemisphere summer insolation anomaly was ca 15Wm_2, whereas at the comparable time in the LIG (130 ka) it was ca 45Wm_2, three times as large.”
How much warmer were Eemian summers? Evidence from the surveyed literature paint a consistent picture. The Atlantic-Siberian sector was typically 4-8C warmer, and Beringia 2-4C warmer. Alaska was 0-2C warmer in summer, but colder in winter. NE Canada and Greenland registered at least 5C warmer in summer. Temperate zones adjacent to the Arctic (and the planetary average) registered roughly 0-2C warmer than the present. This was apparently enough of a difference to facilitate vastly different plant and animal distributions. In some areas plant zones move 1000k north. Trees grew as for north as the Arctic Ocean and hippos swam in the Thames.
The authors argue that the polar region temperature anomalies were so much greater than the planetary average due to positive feedbacks. The warmer Arctic temperatures greatly reduced snow, land and sea ice cover relative to present. This decreased the albedo on land and sea, which resulted in warmer temperatures. While Arctic sea ice cover is rigorously debated, “the available data suggest that sea ice remained through the summer in the central basin.”
There would have been however, much more estensive leads and the ice in places was at least 800km north of the present summer extent. Reduced sea ice and increased meridianal circulation of warm, salty Atlantic waters into the Arctic dramatically warmed Arctic waters relative to the present which then allowed for a much warmer northern Eurasia.
There does not appear to be a consensus on exact ice cover in Greenland. Southern Greenland may have been ice-free or almost ice free while modeled estimates for the Northern Ice sheet are that it was reduced by 20-50%. There is at least solid evidence that some northern sites such as Dye-3 were not glaciated during the Eemian.
While the paper argues that there is indeed “polar amplification of climate change”, the conclusion is again worth quoting:
“The observational records of 20th century warming are not in perfect accord with model projections…The paleoclimate record is more direct… Most of the warming occurred in summer months, whereas model projections indicate winter warming should dominate.”
The authors then illustrate the effects of “polar amplification” during glaciation: While global temperatures are estimated to be roughly 6-8C below present at last Glacial Maximum, Arctic cooling as evidenced by Greenland Ice Sheet boreholes was 25C.
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kadaka (KD Knoebel) says:
September 10, 2010 at 3:29 am
… there has been no statistically-significant global warming since 1998 …
Or more specifically, there HAS been warming since 1998, but it just barely misses out on being “statistically” significant (so it is most likely real, but it could be a random fluctuation). AND that slight warming comes on top of the warmest decade in several hundred years (and perhaps several thousand years, depending on which proxies you believe).
It may be time to retire this sound bite. If 2010 continues as an exceptionally warm year, I suspect that there WILL be “statistically significant” warming since 1998.
Fred says: September 10, 2010 at 2:55 am
So I guess this website has shifted from saying that the ice in the Arctic is recovering to saying that when it melts, it won’t be so bad because it has melted before…
This website is and has always been a repository of wide-ranging analysis, opinion, and debate. There is no single dogmatic line, which is obvious to anyone who cares to examine the incredible body of work presented.
That being said, I have always maintained that Warmer Is Better. So for my part, I have adhered to that dogmatism faithfully. However, I respect and appreciate the diversity of opinion here.
tom says:
September 10, 2010 at 10:34 am
As to disavow… I’ll have to disagree with your interpretation.
Ok, Tom, you missed my point (but in your defense I can see why – poorly worded sentence). I wasn’t asking you to agree or dis my interpretation of the word disavow. I was wondering if you agreed with my interpretation of the authors’ conclusion:
“The observational records of 20th century warming are not in perfect accord with model projections…The paleoclimate record is more direct… Most of the warming occurred in summer months, whereas model projections indicate winter warming should dominate.”
Tom, my interpretation of this conclusion is:
The paleoclimate record ( from multiple sources) indicates most of the warming occurred in the summer months.
Current model projections indicate winter warming.
In other words, what the current GCM models predict will happen is not what the proxies indicate happened under similar circumstances in the Eemian.
I then asked:
If my interpretation is correct and you concur, what word other than disavow would you select?
Please pick from the following: belittle, mock, ridicule, criticize, vilify, disparage, deride, scorn, knock, disdain, scoff; or more along the touchy, feelly lines of distinguish, compare, or discriminate.
Tim Clark says:
September 10, 2010 at 6:15 am
Another point he missed – skeptics let the data lead them to conclusions, not the other way around. in other words, we do not have to cook the books to make a point. We are trying to find out what the point is by allowing the evidence to lead us to it.
AGW proponents reject anything that does not lead them to their preconceived conclusion.
R Gates
I am at a loss to understand your position now. If you accept that the Milankovitch cycles are the dominant effect you must also accept that we are about to enter an almost continuous decline in temperature.
I am not sure if CO2 levels were higher or lower in the Eemian period because I am not convinced that the ice core data give realistic absolute levels. However this is a rather academic point.
There would certainly have been an increase in CO2 as the sea warmed. Assuming this and the supposed increased moisture in the atmosphere (which current models assume) the current models would predict strong positive feedback. So why is it that this interglacial only lasted 16000 years. Where did the tipping point go? Don’t tell me it was because CO2 was not high enough. The IPCC are very clear that the dominant factor in their feedback is the impact of moisture that turns a small CO2 effect into something perhaps six times larger. Moisture does not care how the temperature was increased so if that temperature increase was there then so should be the amplifying feedback.
The fact is that some or all these “greenhouse” effects must be false or are so puny, compared to the orbital effects, that they can do nothing to stop the inevitable.
Hopefully we will eventually find the technology to actually delay or avert the next ice age; but I wager it will not involve CO2.
Enneagram says: September 10, 2010 at 9:50 am
…………….
Earth itself has two equatorial plasma bands,
http://www.nasa.gov/centers/goddard/images/content/154188main_plasma_bands_lgweb.jpg
they are directly related to subtropical jet stream and equatorial weather
http://www.srh.noaa.gov/jetstream//global/images/jetstream3.jpg
Below the plasma bands, a layer of the ionosphere called the E-layer becomes partially electrified during the day. This region creates the plasma bands above it when high-altitude winds blow plasma in the E-layer across the Earth’s magnetic field. Since plasma is electrically charged, its motion across the Earth’s magnetic field acts like a generator, creating an electric field. This electric field shapes the plasma above into the two bands. Anything that would change the motion of the E-layer plasma would also change the electric fields they generate, which would then reshape the plasma bands above.
Santa announces his arrival, next Christmas, on his new Plasma Sleigh over the jet stream, which will go so southward as to making a wall of ice to secure the southern US border from the mexican cartels.
From: Tim Folkerts on September 10, 2010 at 11:43 am
GISS seems to be working hard to make this so. They have declared January-July 2010 to be the warmest in their 131-year record.
Check out the recent history. Looking at the three latitude bands, from 2001 to 2008 the low latitudes (23.6°N to 23.6°S) were cooling, the southern latitudes (23.6° to 90°S) were holding steady, the warming was in the northern latitudes (90°N to 23.6°N) but the temps nosedived between 2007 and 2008. This was mostly corrected in 2009 with the adoption of the USHCN_V2 dataset, the low and southern latitudes show large increases for 2009, although the northern latitudes still had a small decrease. The hemispheric chart was made right again, with the Southern Hemisphere annual mean now showing a proper large jump for 2009 while the Northern Hemisphere, with its part of the low latitude increase, managed to display a noticeable rise.
Guess that lack of statistically-significant global warming since 1995 (not 1998, my mistake) and non-statistically-significant global cooling since January 2002 was getting kind of embarrassing. Someone had to step forward and verify the science!
In fact, the presence of an icecap in the Arctic Circle is very abnormal. There are very few occasions in the Earth’s more than 4 billion year existence when an icecap has been present in the Arctic, even during the occurrences of ice ages with extensive icecaps in the Antarctic Circle. Before the currently ongoing ice age and interglacial period, there was an icecap in the Arctic for awhile during the Permian. Before the Permian you must go backwards to a time before there were any trees or flora on the continents to find an icecap in the Arctic.
Life and biodiversity flourished when the temperatures were greater than the past century, and they suffered when the climactic conditions were the same as the past century and colder.
AGW, Global Warming, Climate Change activists often cite the precautionary principle as an excuse for taking actions in the absence of conclusive evidence, yet they refuse to take note of the general destruction of most of the life on this planet if it were ever possible for them to actually cause the decrease of carbon dioxide concentrations in the atmosphere by half or more and thereby end the photosynthesis of most or virtually all plant life. Such an act upon their part would make all of the genocides perpetrated by other socialists such as the Khmer Rouge, Communist Chinese and Mao, Soviets and Stalin, Hitler and the NSDAP, and all predecessors totally insignificant by comparison.
vukcevic says:
September 10, 2010 at 1:56 pm
Remarkable!. And those bands are up there, these are real not computer games, driven by the Sun and not by a Joystick.
R. Gates (11:21 am):
“….what the planet has seen over the past 250 years or so is a human CO2 volcano whereby humans are releasing large amount of CO2 via the burning of fossil fuels…”
That is incorrect.
The human “CO2 volcano” did not begin to erupt until after WW2 and the only net warming observed since then was between 1980 – 2000:
http://cdiac.ornl.gov/trends/emis/graphics/global_ff_1751_2006.jpg
I dud the google thing. It looks like this claim by Peter Hodges is wrong.
———–
It is widely accepted that the last interglacial was much warmer than the current.
———–
wikipedia reckons the global average was much the same as now, since the southern hemisphere temperatures were lower thus balancing the higher northern. Basically a Milankovitch cycle effect.
Guys please stop forgetting about half the planet.
LazyTeenager (great nic),
The southern hemisphere temperatures mirrored the northern hemisphere ones. There is not quite as much variability in the south as in the north but generally the temperatures follow the same track.
The 800K ice core record from Antarctica.
http://img707.imageshack.us/img707/5052/last800k.png
And then an 800K year high resolution record from north Atlantic Ocean proxies versus the Antarctic temps. (The chart is very busy but one should be able to get the idea). Note these proxies provide a different temperature record that those from the Greenland 110,000 year ice core data but I generally think the Greenland ice core data is not being calibrated properly. (the Younger Dryas needs to be berry berry scarry).
http://img340.imageshack.us/img340/4670/last800knaant.png
——————
Regarding the Milankovitch Cycles, I think it is important for people to understand that its changes are very, very, very small. They really should not be able to put the Earth into and out-of ice ages.
In concrete terms, it is 300 kms.
The variation in solar energy in the summer is only a change of +/- 150 kms. At the height of a downturn in the Milankovitch Cycles, Chicago’s has summer sunshine like Milwaukee (just an hour and half north up the road). At the peaks of the Milankovitch Cycle, Chicago’s summer sunshine is like Bloomington Illinois (just down the road again).
It should make no difference at all really.
But let’s say, the location is now the Arctic Ocean or Ellesmere Island or northern Greenland. Now that total change of 300 kms in summer sunshine is just enough so that the Arctic sea ice doesn’t melt anymore (it only takes a degree or so). The snow doesn’t melt completely in the summer at the higher elevations on Ellesmere Island and northern Greenland.
The glaciers can only advance south if enough ice builds-up first and reflects more sunshine. The glaciers are always on a precarious balance where they frequently advance and retreat and what we have is much more variability in the northern hemisphere Ice Albedo and hence its temperatures. The glaciers are always melting profusely in the summer when they get down to Chicago, sometimes they back up to Winnipeg and then they advance again back down to Chicago.
During the Younger Dryas, the glaciers still covered all of Hudson Bay and more than half of Canada. It was just the last advance stage.
The forecasts for the Milankovitch Cycle (and these can be accurate out 5 million years) is that we are not going to have a big enough downturn to put us into another ice age for perhaps 50,000 years.
This interglacial should be twice as long as the last longest one at 400,000 years ago (see charts above) where Greenland’s glaciers melted out of at least the bottom third of Greenland and forests actually grew in that area (as well as on Ellesmere Island and Baffin Island). We are in the good part of the Milankovitch Cycles if one is concerned about human civilization.
The only significant warming there has been since about 1998 has been in the falsified datasets that are being increasingly corrupted with fantasy adjustments to fit the propaganda messages. We can see it it the plants we grow in gardens located in widely separate regions throughout the United States. We have plants which were too intolerant of cold weather to grow in Washington, Wisconsin, and New York in 196,1976, and 2010 that were thriving moderately well in 1995 to 1998. The cycle has changed, and it is getting colder during the past ten years as it returns to what we experienced about 1954 to 1979 in Virginia, Georgia, Tennessee, Kentucky, New York, Indiana, Illinois, Michigan, Wisconsin, Minnesota, Pennsylvania, Missouri, Kansas, Arizona, California, Oregon, Washington, Great Britain, Belgium, the Netherlands, Germany, Switzerland, Austria, Italy, Spain, France, Egypt, India, Japan, the Phillipines, Australia, New Zealand, Brazil, Bolivia, and Chile…to name a few.
From: madmike.davies@hotmail.com
To: newideas@fcpp.org
Subject: FW: A new view of the Earth and its climate
Date: Fri, 3 Sep 2010 19:59:57 +0000
I have an idea for a science book, theory, on climate change, it is not solely about climate change but also about the physics of the Earth Sun System, it´s operation is analagous to an operational amplifier in electronics. By treating the earth as a homogenous and isolated simple Thermal Amplifier, it can be shown that the Holocene temperature record exhibits the properties of damping since the CO2 levels in the atmosphere levelled out at the end of the last ice age The so called Anthropogenic C02 has stopped our climate from large climate shifts and is good for the earth.
The documents Modelling & Function of the Earth as a Thermal Amplifier is the core of the theory. These can be found on my Weblog http://madmikedavies.wordpress.com/comments/feed/
Since I wrote this it has been brought to my attention that Bill Ruddiman has published several books which have some agreement with my theory but the physical design of the thermal amplifier effect is my own.
The theory is based on Milankovich cycles, as the energy input source.
I was driven to writing this theory by erroneous science programs on the television. I did all my research on wikipedia, and most of the information to prove the theory is in the public domain. I studied all the necessary basic science in Geology, Plate Techtonics, Astrophysics, Physics, and Chemistry at thr Open University in the 1980´s
I believe that as a generalist and not a specialist I have been able to see the bigger picture
Another logical outcome of my theory is that Human Evolution is a function of the evolution of the Earth. The theory states that we evolved our intelligence in the face of a cooling world and the reason for this was to reverse the cooling trend. Evolution of intelligence allowed us to control our environment, and as a consequence we changed the climate of the Earth. This process is irreversible as long as humanity survives, the next logical outcome is to achieve thermal equilibrium, which from the paleoclimate record is about 3degC warmer than current and requires a C02 level of 600ppm or roughly 3 times the Holocene average.
I have started a weblog at
http://madmikedavies.wordpress.com/comments/feed/
regards
Mike Davies
Retired Communications Engineer, living in Portugal. Interests are Cosmology, Earth Sciences, Organic farming, Climatology, Football, Golf, Birdwatching, and Dogs
LazyTeenager says:
September 10, 2010 at 4:48 pm
It’s really hard not to notice the obsession with half the planet.
But that is to be expected, as Climate Change (nee AGW) is half a theory, the other half being pinned on a trace gas (thin air). Be sure to watch Joe Bastardi’s Monday Sea Ice report. His approach is level-headed, as most good meteorologists are.
R. Gates says:
“… Current CO2 levels are far higher than they’ve been for at least 400,000 years, and likely even longer. The Milankovitch cycles are the most likely driver behind the Eemian and the Holocene Optimum, and CO2 levels were about the same during both at about 260-280 ppm. Essentially what the planet has seen over the past 250 years or so is a human CO2 volcano whereby humans are releasing large amount of CO2 via the burning of fossil fuels in a geologically short period of time. The current warming may or may not be related to this, but I think it far more likely than not that it is, as there is currently no other known cycles to account.
In short, the warmth during the Eemian or the Holocene Optimum in no way disprove current AGW from CO2 release– and if anything, they confirm the basic notion of polar amplfication during warm periods just as GCM’s predict will happen with AGW.”
_________________________________________________
Mr Gates…. You still miss the point also….. The Current warming actually started in 1700, after a long period of cooling…. From then on, the planet has warmed. A question could be posed. What caused the cooling between 1360 and 1700? It certainly wasn’t a decrease in CO2, nor anything to do with Milankovitch cycles.
On the same token, as the increase in CO2 was nil or negligible up until 1930…. What caused that warming trend?…
Then between 1940 and 1976 there is a cooling in global temperature but a very significant increase in CO2… You described it as a “Human CO2 Volcano”…. But we recorded a cooling…? Very strange as far as promoting the hypothesis of AGW goes, don’t you think Mr Gates?
J.Hansford says:
September 10, 2010 at 10:01 pm
=========================
All great points.
But count on your logic falling on deaf ears.
Chris
Norfolk, VA, USA
Bill Illis says:
September 10, 2010 at 5:46 pm
LazyTeenager (great nic),
Regarding the Milankovitch Cycles, I think it is important for people to understand that its changes are very, very, very small. They really should not be able to put the Earth into and out-of ice ages.
What has “should” got to do with it. In the following graphic:
http://en.wikipedia.org/wiki/File:Milankovitch_Variations.png
Every one of the 11 interglacial (IG) peaks in the last million years has coincided with three (inter-related) things:
– peaks in amplitude of precession oscillation
– peaks in amplitude of solar forcing oscillation
– peaks in eccentricity
This correlation seems too much to be a fluke. The relationship is there and the starting point of research is why is it there – rather than denial of Milankovich forcing of glacial-interglacial cycle. One might as well argue that night and day are some sort of illusion and the reality is a continuous twilight. I can understand a climate establishment trying to gently draw people’s gaze away from these inconvenient facts.
I guess the party line is fear of the consequences of the MSM and general public getting into a scare about an impending ice age.
I have never understood this complacent hypotheses that the current IG will last 50,000 years. What exactly is meant by length of IG? There is a big difference between the width or FWHM of an IG peak, and the width of a plateau at the top. Our present warm conditions represent the top plateau of the holocene. Temperatures at the mid-peak or FWHM are at least 3C cooler globally. Conditions at the IG peak FWHM are “semi-glacial”.
It is true that the precession and solar amplitude peaks and the eccentricity peaks are small right now just like 400 kyrs and 800 kyrs ago. But the IG peaks at both those times also had narrow peaks (although the 400 kyr IG had a wider waistline). The 800 kyr peak was a regular IG peak like all the rest.
Every single one of the last 11 interglacial peaks have been just that – peaks. To argue now for a 50,000 year platuea would be to argue for something totally breaking the pattern of the last million years – you would need a good reason for this. Perhaps the argument is that the present glacial epoch is over?
The graph at the top of this post shows that the insolation peak initiated the start of the interglacial – but the insolation does not coincide with the interglacial – it falls back as the IG proceeds. By the IG midpoint the insolation is already well past its peak.
Some of the IGs coinciding with the solar and orbital Milankovich peaks are kind of double-peaks, e.g. at 200k, 500k and 600k yrs ago.
On the gross scale the pattern is a saw-tooth of rapid temperature increases at the start of each IG and then slow ragged decline toward glacial maxima that are reached only just before the next IG. However, the IG peaks are peaks, and the start of the decline after an IG is always a sharp drop of 1 or 2 C globally.
At a finer scale looking at more recent data, it is evident that within the Holocene, temperature peaks are also peaks, with a sharp rise and fall separated by more ragged oscillation.
http://globalwarmingskeptics.info/forums/thread-188-post-3123.html#pid3123
(Thanks to sunsettommy!)
The one thing absent from the whole temperature record is any sort of plateau.
Enneagram says:
September 10, 2010 at 2:53 pm
vukcevic says:
September 10, 2010 at 1:56 pm
Remarkable!. …………..Connection between weather in the tropical regions and the Earth’s magnetic field is clearly demonstrated in the updated link:
http://www.vukcevic.talktalk.net/LFC20.htm
Weather forcasters watch the sky. Climate forcasters watch the trees. (Of course etamilcologists –‘climate’-olo-gists spelled backwards– only watch their bank accounts and their last TV interview over, and over, and over…)
[And their backs! ~jove, mod]
phlogiston says:
September 11, 2010 at 1:33 am
We have all seen the Milankovitch Cycle charts. But what we have not seen is the temperature cycles and the Milankovitch Cycles on the same chart so we could actually see the correlation.
And the match is not good at all. Here is the last 3 ice ages against the solar forcing at 75N.
http://img109.imageshack.us/img109/9195/milkanvsiceages.png
And here is the last 800K years.
http://img341.imageshack.us/img341/8735/milankovitch800k.png
One can play around with the numbers and take 65S or 65N or just the 100K year orbital cycle or the 41K axial tilt cycle and none of them really work any better.
A paper by Gerald Roe seems to have made the best analysis on how this system works. Generally, it is the change in ice balance – the delta ice balance (driven by the change in summer solar insolation) which governs the ice age cycles. So much ice can build up at certain points, that there is just not enough melt in high individual Milankovitch peaks to bring the system into an interglacial. The interglacials only hit every third or fourth Milankovitch peak. It will now take a really big downturn to bring back a high ice balance and the forecasts do not predict that for a long time.
http://earthweb.ess.washington.edu/roe/GerardWeb/Publications_files/Roe_Milankovitch_GRL06.pdf
Bill Illis says:
September 11, 2010 at 6:05 am
Thanks for the helpful reply and the Roe paper. I would certainly agree that trying to fit the start and end of all IGs to an individual insolation peak is diffiult and not persuasive – Roe admits this effectively on one passage:
It is not possible to unequivocally attribute a climate
response to an insolation forcing at a particular latitude and
season because, to a good approximation, any such forcing
can be constructed from a linear combination of climatic
precession and obliquity indices [Imbrie and Imbrie, 1980].
In theory then, an infinite set of insolation curves (or their
meridional gradients) can be matched with a given climate
signal, leaving the physical mechanisms producing the
climate response ambiguous.
But why are we sure that insolation per se is the key player? What jumps out of the graphs to me is that it is not individual peaks of insolation (there are too many of them) that are convincing forcers between glacial and IG, nor even the average value of insolation, but rather the amplitude of the oscillation of insolation. The maximum amplitude peaks coincide with the IG onset every time.
Why? As Roe says the mechanism is ambiguous. What we know is that at the eccentricity maxima, the rates of change of both insolation and precession (amplitude of oscillation regardless of individual peaks) are also maximal. Perhaps this is a clue, but what physical processes could this entrain? I think Roe is right to draw attention to rates of change rather than individual values of parameters – he applied the principle to ice volume but the same could be applied to the astrophysical orbital parameters.
My main original point (sorry for the shrill tone of the earlier post) was that – despite the complex raggedness of the temperature reconstruction and the differences in IG shapes due to changing amplitude of orbital parameters, the peak tops of all the IGs are all sharp. (The current one is already a bit of an exception by being flattish for ~10k years.) One should expect it also to drop “sharply” (on a scale of kilo-years) soon, not straight to full on glacial but at least a degree or two, as the (always rapid) start of a protracted – and sometimes interrupted – decline. A long prolongation of the current IG at current temperatures for 50k years would look very strange – it would look like the end of the current glacial epoch.
OT – but get this if you like cool astronomy photos:
http://www.bbc.co.uk/news/science-environment-11213528
J.Hansford says:
September 10, 2010 at 10:01 pm
Then between 1940 and 1976 there is a cooling in global temperature but a very significant increase in CO2… You described it as a “Human CO2 Volcano”…. But we recorded a cooling…? Very strange as far as promoting the hypothesis of AGW goes, don’t you think Mr Gates?
The mere matter of over 700 atmospheric atomic tests between 1945 and 1980 injecting particulates into the stratosphere likely had something to do with that.