Sobering graphics to scale: ice sheets 21,000 years ago versus today’s skylines.
“Data adapted from ‘The Laurentide and Innuitian ice sheets during the Last Glacial Maximum’ by A.S. Dyke et. al., which was way better than the sequels ‘The Laurentide and Innuitian ice sheets during the Last Glacial Maximum: The Meltdown’ and ‘The Laurentide and Innuitian ice sheets during the Last Glacial Maximum: Continental Drift’.”
h/t to reader “View from the Solent”
No, the hockey stick was falsified by a fellow named Steve McIntyre looking into it and finding that the statistical analysis was botched. Several other people, including the inventor of the technique, agree.
Then people discovered several other things that Mann et al did that are questionable, wrong, or backward.
Not at all. One weekend I saw two or three reports of warmer conditions than now only 6,000 years ago. There may be several others. These are based on observations of trees and people being uncovered by the current glacial retreat.
Imagine being at the face of a melting glacier. The melt stream is milky with rock flour, the scoured valley has patches of low alpine plants struggling with the poor soil and short growing season – but there are pieces of full sized trees in the face of the glacier.
Sorry, only 6,000 years. See http://wermenh.com/climate/6000.html
@TWS
Hmmm your logic seems to be consistent with this lady’s:
Are you the same person as her?
JM VanWinkle says:
June 14, 2013 at 6:59 pm
Maybe time for another big sleep? 🙂
Sorry but I am skeptical
Tom in Florida says:
June 15, 2013 at 5:58 am
“However, as the good Dr S reminds us, eccentricity will be too low for the next 50,000 years for us to fall back into a glacial period.”
I have heard that thinking before, but it is inconsistent with the geologic record that interglacials end with the next point in obliquity passing 23.5 degrees (or thereabouts), very inconsistent. It is why the interglacials are only about 10k years, never significantly longer. You can see the record yourself, it is quite clear. I like theories to be consistent with the geologic record. Still, if Dr. S is talking about what will cause the next interglacial after the Holocene ends, that is another matter as the point of interglacial beginnings is variable, based on the record. As for me, that is further into the future than is personally interesting to me. Others maybe more optimistic.
I hope that makes sense.
Billy L, unfortunately insomnia has its own cycles which I also don’t understand.
A good display of how bad ice ages are. AWhere did it come from? It can only be the equator, where water would still be evaporating, not being below zero, but falling as snow, and not melting, in the Northern AND Southern regions. Homo Sapiens were around on the planet, this was only 21,000 years ago. Human civilization took off after the recession of the ice.
We had fire and weapons and stone tools before. But after the ice age, we also had clothes and agirculture.
JM VanWinkle says:
June 15, 2013 at 2:48 pm
“I have heard that thinking before, but it is inconsistent with the geologic record that interglacials end with the next point in obliquity passing 23.5 degrees (or thereabouts), very inconsistent. It is why the interglacials are only about 10k years, never significantly longer. You can see the record yourself, it is quite clear. I like theories to be consistent with the geologic record. Still, if Dr. S is talking about what will cause the next interglacial after the Holocene ends, that is another matter as the point of interglacial beginnings is variable, based on the record. As for me, that is further into the future than is personally interesting to me. Others maybe more optimistic.
I hope that makes sense.”
It makes sense unless we have an extended period of low eccentricity, which occurs about every 400K years. Low obliquity with low eccentricity will prevent the longer periods of colder temperatures that the Earth would have to go through to have a new glacial period.
Re: Ric Werme says:
June 15, 2013 at 12:41 pm
“…..This means that we would probably have to go back to the warmest since warm to get temperatures that are similar to those we are experiencing today.
Not at all….”
Thanks for taking the time to explain to the misguided, Ric. I get tired of explaining the fact when Roman stuff is buried by dark ages snow, not quite uncovered by Medieval thawing, reburied by Little Ice Age snows, and now reappears, it means it has gotten back to the warmth of Roman times 2000 years ago, not that it is the first time it has been this warm in 125,000 years.
It gets tiring saying the same thing over and over and over again, so I’ve been trying to jazz it up recently by telling tales of Hannibal crossing the Alps with elephants. However when you introduce new stuff you learn new stuff. There may not have been snow up in those passes, back then, but still it was pretty cold for elephants. Apparently some got pneumonia and died. Hannibal should have had huge blankets for the poor beasts. If a few woolly mammoths had survived to his time, Rome might have lost that war.
By the way, that’s a good collection of stories about finding wood in glaciers at your website http://wermenh.com/climate/6000.html. I saved the link for future reference.
Caleb, the Romans learnt to part ranks to leave passage for the elephants, as they did with Bodacia’s scythed chariots.
We undoubtedly ARE approaching the end of the current interglacial and by all indications are overdue for the next ice age. That means the climate is close to the tipping point. The consequences of an ice age commencing really would be catastrophic as the xkcd panels illustrate. We came very close to tipping into a full ice age during the LIA triggered by the Maunder minimum. It was a lucky escape. Note how quickly the world cooled and how long it took temperatures to recover. Many skeptics like myself are more concerned that the greenhouse effect from added CO2 might not be large enough to help us escape from ice age during the currently commencing solar minimum. An ice age really is catastrophic in a way that a warmer world is not. Just look at the XKCD panels.
A warmer world means longer growing seasons – less frost – faster growing crops due to CO2 fertilisation – higher average rainfall – and less extreme weather overall due to lower temperature contrasts. There is absolutely no evidence in the geologic record of any kind of tipping point in the climate on the warm side. That some GCMs predict this is merely more evidence of the failure of GCMs. In fact the evidence is that the climate is quite stable on the warm side. I’d therefore be very happy to see the world move away from the edge of the ice age precipice by warming a bit.
For a start, the hockey stick is simply wrong. The mathematics it used is completely broken. It is a scientific error so why are we even talking about it.
What you call the “medieval climate anomaly” the rest of us are happy to call the medieval warm period. By all historical accounts the climate at that time was benign and human civilisation flourished and spread. Your use of the word “anomaly” to describe this period is judgemental and suggests that the climate at that time was atypical, unnatural or abnormal. How can you possibly justify that judgement? The weather in the MWP – far from being anomalous – was fairly typical of most of the holocene. The anomalous climatic episodes are the cold periods like the LIA which have been gradually becoming more frequent and more severe. Eventually one of these will tip us over the edge into true ice age. Most of us will then die of starvation and our cities will be obliterated by miles high walls of grinding ice. That is true catastrophe.
Alarmists have to work very hard indeed to make a warmer world sound alarming. Some of their stories are frankly ridiculous. Weeds will grow faster (all plants will grow faster!). Crops may have a slightly lower protein content (because they will be vigorous, healthy, and bursting at the seams with sugars – eat meat if lack of protein worries you). Mosquitoes may spread further (conditions will be benign for all life – so spend a bit more on mosquito control – problem sorted). That they have to work this hard to find the dark lining in the silver cloud illustrates that a warmer world is not a problem. A colder world on the other hand is a very scary possibility.
Eric’s paper in Science is at best Fraudulent, and dismissible with 30 seconds of clear thinking. Yet, his paper in Science IS necessary for the AGU to give him an award (tainted paper) and money ($10K of tainted paper). With certainty Eric will deliver five talks at the AGU which only allows at most three, but the AGU is the home of Peter Gleick the fraudster, and pal of the AGU intelligente.
PiperPaul says:
June 14, 2013 at 7:38 pm
Back in the ’70s, our balls were taken away from us in the name of feminism.
=========
The only “humor” shown on TV these days is to portray white males as stupid. If you tried this with females it would be sexist and if you did it with any other race it would be racist.
For some reason however, prejudice against white males is permitted by society and TV broadcast standards. I call it a double standard. If it is wrong to “make fun” of women, blacks, orientals and hispanics, then it is surely wrong to “make fun” of males, whites and any other groups. Otherwise, if it OK to “make fun” of white males, then surely it is equally correct to “make fun” of any group.
Email, write and phone in your complaints to the TV station, regulators and legislators whenever you see this sort of sexist and racist portrayal of any groups, including white males. You will be surprised to find that many people that consider themselves “progressive” cannot see that stereotype portrayals of white males is both sexist and racist.
Do your bit to bring up the subject at the next cocktail party you attend. You may be surprised how many people do not even see the problem. Educate them. It is the first step in growing a pair.
Midwestern farmers remember the basic rules for ice vs. liquid water, thelastdemocrat … 10 inches of snow, depending on how wet it is, of course, equals only an inch of water, i.e. water EXPANDS as it freezes. So that’s why the ice towering over the skyscrapers seems disproportionate to the amount of water now in the oceans.
“However, as the good Dr S reminds us, eccentricity will be too low for the next 50,000 years for us to fall back into a glacial period.”
===============
Similar arguments were made 80 years ago to discredit Milankovitch. Until the ocean cores were sampled in the 70’s.
The problem for Sr S and climate science in general is that we do not have sufficient understanding of the problem or the mathematics to make reliable predictions. Thus for example, the 100,000 year problem in climate science.
http://en.wikipedia.org/wiki/100,000-year_problem
Spectral analysis shows that the most powerful climate response is at 100,000-year period, but the orbital forcing at this period is small.
This would appear to contradict Dr S’s assurances that small orbital forcing prevents ice ages. While that might be true in linear systems, in non-linear and chaotic systems no such limitation exists.
S.D. skeptic says:
June 15, 2013 at 9:43 pm
Midwestern farmers remember the basic rules for ice vs. liquid water, thelastdemocrat … 10 inches of snow, depending on how wet it is, of course, equals only an inch of water, i.e. water EXPANDS as it freezes. So that’s why the ice towering over the skyscrapers seems disproportionate to the amount of water now in the oceans.
This is so wrong. Sorry, it is a valiant try but …. snow is very loosely packed and consists of ice plus quite a lot of air. So, roughly 10-12 inches of snow -> ca. 1 inch of water because of that air, not the expansion of ice, which only makes a brief turn around before continuing to shrink as it gets colder.
In regards to ice sheets and why the ice vs. skyscraper scene might seem disproportionate, it is really because all that ice is now water, and back in the ocean basins. Since those basins cover about 3/4s of the planet, and those oceans are 300 feet deeper! now than they were then, well, it really isn’t so disproportionate at all. There was a lot of land, dry back then, that requires a submarine to visit now, that or very highly specialized diving gear. It’s too bad the artist didn’t include the mile worth over New York.
Tom in Florida,
Thanks for that explanation on eccentricity. Also despite CO2 hijacking climate science, some work is seeping through the Warmist Barrier. I was scouting for information and found this in my archive:
“(Boston) –Through dated geological records scientists have known for decades that variations in the Earth’s orbit around the sun – subtle changes in the distance between the two – control ice ages. But, for the first 2 million years of the Northern Hemisphere Ice Age there has always been a mismatch between the timing of ice sheet changes and the Earth’s orbital parameters.
A new model of ice volume change developed by Boston University researchers Maureen Raymo and Lorraine Lisiecki proposes a reason for this discrepancy…
“Because summer insolation is controlled by precession, and summer heating controls ice sheet mass balance, it is difficult to understand why the ice volume record is dominated by the obliquity frequency,” said Dr. Raymo. “It’s not a complete mismatch, but the precession frequency we think should be strong in geological records is not.”
The new model proposes that during this time, ice volume changes occurred in both the Northern Hemisphere and Antarctica, each controlled by different amounts of local summer insolation paced by precession.
“The reason the frequency is not observable in records is because ice volume change occurred at both poles, but out of phase with each other. When ice was growing in the Northern Hemisphere, it was melting in the Southern,” said Raymo.
The team believes scientists have been operating under the assumption that Antarctica has been exceptionally stable for 3 million years and very difficult to change climatically. “We don’t tend to think of ice volume in that region as varying significantly, even on geologic time scales,” said Raymo. “However, only a modest change in Antarctic ice mass is required to “cancel” a much larger Northern ice volume signal.”
There also was a newer article from Lorraine Lisiecki on eccentricity and the 100,000 year cycle.
Best regards
ferd berple says:
June 15, 2013 at 9:57 pm
JM VanWinkle says:
June 16, 2013 at 1:10 am
I do not think that any one parameter controls climate change, as is discussed on this blog frequently. But insolation change brought about by orbital change certainly has to be a major player. Earth’s most natural state is glaciation and interglacial warm periods are the exception, which have been occurring about every 100,000 years for some time now. Now we know that an interglacial started 10-12,000 years ago so if we look at the orbital parameters then we can say with some certainty that when eccentricity is lower, obliquity is high and NH summer solstice is at perihelion, an interglacial happens. Each of these orbital parameters has a different cycle period but we can retrace those combinations in time to see when the same combinations came together in history. My rough calculations show that the proper combination of the 3 orbital parameters for an interglacial to begin happens about every 100,000 years. So it is not solely the eccentricity period of 100,000 years but the proper combination of all 3 parameters, which just happen to be about 100,000 years. But eccentricity now is in the 400,000 year pattern which will keep it low for the next 50,000 years or so. This low eccentricity should prevent long cold spells that usually bring on glaciations regardless of the other 2 parameter changes. So it looks like we will have our current general climate (with all it’s colder and warmer periods) to remain as is for 40 – 50,000 years. We could then enter only a brief period of glaciation because in 90,000 years all 3 parameters will again match up to the proper combination for the next interglacial. . After that, I really don’t care :).
Tom,
The importance of eccentricity varies from theory to theory, but most discount it. Here is what Dr. Lorraine E. Lisiecki’s dissertation says:
The 100-kyr Cycle
Virtually all models of the 100-kyr glacial cycle in the late Pleistocene rely on the argument that long time constants in the climate system favor a 100-kyr glacial cycle by decreasing the climate’s sensitivity to the more rapid variations of precession and obliquity. Theories differ in the source of the long time constant, but popular suggestions are large ice sheets and their underlying bedrock [Weertman, 1964] or the global carbon cycle [Shackleton, 2000]. A direct response to eccentricity is unlikely because it has very little net effect on annual insolation and because the 400-kyr power of eccentricity produces little response in late Pleistocene climate.
Most models differ in the extent to which eccentricity and nonlinear responses to obliquity and precession drive 100-kyr glacial cycles. One group of theories holds that 100-kyr oscillations are self-sustained, requiring no external forcing [e.g., Maasch and Saltzman, 1990; Tziperman and Gildor, 2003]. Even if variability is self-sustained, orbital forcing may still play an important role in pacing 100-kyr glacial cycles [Huybers and Wunsch, 2005]. Another group of theories posits that nonlinear responses to obliquity and/or precession result in conditions conducive to deglaciation with a period of approximately 100 kyr [e.g., Raymo, 1997; Paillard, 1998; Ruddiman, 2003]. Finally, it is possible to produce 100-kyr power in climate models simply by introducing different rates of ice sheet growth and decay [Imbrie and Imbrie, 1980]. One very different model proposes that 100-kyr cycles in orbital inclination may force late Pleistocene glacial cycles [Muller and MacDonald, 1997], but very little support exists for forcing mechanisms associated with inclination [Winckler et al., 2004].
Possibly many would ask how do we know how thick the ice sheet was at any location. It comes from “soil mechanics” the behaviour of natural clays under loading. Experimentally, if you take a core of undisturbed clay and load it with a certain weight on a piston and cylinder arrangement, the clay compresses to a certain level. If you now take this clay and reload it, there is no added compression until you exceed the former loading and the compression curve then continues where it left off from the previous experiment. Clay layers that have been under the compression of glacial ice behave the same way. A number of cores in a given area are taken, each placed in a compression cylinder and loaded until the beginning of compression of the clay. This figure, with good repeatability represents the load/square area that this clay has been under in the past – a complete memory of the compression event. Cool, huh?
Tom, here is a poster of a temperature poxy ice, δD (Antarctic temperature) in grey that you can download as a pdf. When I look at it, the 400k BP interglacial is about 10k years also. See what you think.
http://lorraine-lisiecki.com/lisiecki_poster_agu08.pdf
A sheepsfoot roller is used to compact and densify soils for roads – resistance to further compaction and and earth-filled dams – to provide the strength and resistance to hydraulic lifting in the soils- same principle of the compaction measurement of my above comments
http://web.mst.edu/~rogersda/umrcourses/ge441/online_lectures/compaction/GE441-Lecture2-1.pdf..
On a clear sunny day the sun’s intensity occurs at midday but the maximum temperature happens around 3 hours later. Other conditions result in a widely different time of day for the maximum temperature; sometimes during the middle of the night.
Why would the Milankovitch cycles each not have a time lag? These time lags would not be the same and could, in combination with climate response, change. A summation could generate (overall) periods that are at present about 90 ka, that oscillate wildly between an overall cycle: adding constructively and destructively where one or the other prevails. But hahaha there could even be an as yet undiscovered astronomical input that could rationalize the quantal change in period of the last couple of millions of years.
So how big will the space mirrors need to be to be to reflect enough additional sunlight to avoid glaciation?
Forgot to link;
http://4.bp.blogspot.com/-FgaPchYinO8/UMD2PwSKlWI/AAAAAAAAADs/K3_d49i_GME/s1600/400000yearslarge.gif