Study: the Greenland ice sheet collapsed 400,000 years ago

From Oregon State University

Study links Greenland ice sheet collapse, sea level rise 400,000 years ago

CORVALLIS, Ore. – A new study suggests that a warming period more than 400,000 years ago pushed the Greenland ice sheet past its stability threshold, resulting in a nearly complete deglaciation of southern Greenland and raising global sea levels some 4-6 meters.

The study is one of the first to zero in on how the vast Greenland ice sheet responded to warmer temperatures during that period, which were caused by changes in the Earth’s orbit around the sun.

Results of the study, which was funded by the National Science Foundation, are being published this week in the journal Nature.

“The climate 400,000 years ago was not that much different than what we see today, or at least what is predicted for the end of the century,” said Anders Carlson, an associate professor at Oregon State University and co-author on the study. “The forcing was different, but what is important is that the region crossed the threshold allowing the southern portion of the ice sheet to all but disappear.

“This may give us a better sense of what may happen in the future as temperatures continue rising,” Carlson added.

Few reliable models and little proxy data exist to document the extent of the Greenland ice sheet loss during a period known as the Marine Isotope Stage 11. This was an exceptionally long warm period between ice ages that resulted in a global sea level rise of about 6-13 meters above present. However, scientists have been unsure of how much sea level rise could be attributed to Greenland, and how much may have resulted from the melting of Antarctic ice sheets or other causes.

To find the answer, the researchers examined sediment cores collected off the coast of Greenland from what is called the Eirik Drift. During several years of research, they sampled the chemistry of the glacial stream sediment on the island and discovered that different parts of Greenland have unique chemical features. During the presence of ice sheets, the sediments are scraped off and carried into the water where they are deposited in the Eirik Drift.

“Each terrain has a distinct fingerprint,” Carlson noted. “They also have different tectonic histories and so changes between the terrains allow us to predict how old the sediments are, as well as where they came from. The sediments are only deposited when there is significant ice to erode the terrain. The absence of terrestrial deposits in the sediment suggests the absence of ice.

“Not only can we estimate how much ice there was,” he added, “but the isotopic signature can tell us where ice was present, or from where it was missing.”

This first “ice sheet tracer” utilizes strontium, lead and neodymium isotopes to track the terrestrial chemistry.

The researchers’ analysis of the scope of the ice loss suggests that deglaciation in southern Greenland 400,000 years ago would have accounted for at least four meters – and possibly up to six meters – of global sea level rise. Other studies have shown, however, that sea levels during that period were at least six meters above present, and may have been as much as 13 meters higher.

Carlson said the ice sheet loss likely went beyond the southern edges of Greenland, though not all the way to the center, which has not been ice-free for at least one million years.

In their Nature article, the researchers contrasted the events of Marine Isotope Stage 11 with another warming period that occurred about 125,000 years ago and resulted in a sea level rise of 5-10 meters. Their analysis of the sediment record suggests that not as much of the Greenland ice sheet was lost – in fact, only enough to contribute to a sea level rise of less than 2.5 meters.

“However, other studies have shown that Antarctica may have been unstable at the time and melting there may have made up the difference,” Carlson pointed out.

The researchers say the discovery of an ice sheet tracer that can be documented through sediment core analysis is a major step to understanding the history of ice sheets in Greenland – and their impact on global climate and sea level changes. They acknowledge the need for more widespread coring data and temperature reconstructions.

“This is the first step toward more complete knowledge of the ice history,” Carlson said, “but it is an important one.”

###

 

Lead author on the Nature study is Alberto Reyes, who worked as a postdoctoral researcher for Carlson when both were at the University of Wisconsin-Madison. Carlson is now on the faculty in Oregon State’s College of Earth, Ocean, and Atmospheric Sciences.

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wws
June 25, 2014 1:43 pm

So that’s what happened to Atlantis, them and their dirty carbon fuel habits.

June 25, 2014 1:49 pm

At least they are now talking about the cores being a LOCAL record. The quality of the research is now getting better thanks to some very smart people taking the bad science to the woodshed.

Lucius von Steinkaninchen
June 25, 2014 1:53 pm

So much for the overuse of the word “unprecedent” in AGW scaremonging headlines.

milodonharlani
June 25, 2014 1:55 pm

I have commented on this blog before about the super-interglacial of ~400,000 years ago, in which the southern dome of the Greenland Ice Sheet largely disappeared. Same apparently happened some 800,000 years ago. Scientists disagree as to whether the current interglacial, the Holocene, will last as long as MIS 11. I went round the mulberry bush with Lord Monckton on the issue of the likely time remaining for the Holocene.
Based upon orbital parameters, the now ~11,000 year-old Holocene could go super, like MIS 11’s tens of thousands of years in duration, but against that forecast is the fact that for at least the past 3000 years, earth’s climate has been in a cooling trend, which if simply extrapolated would get us back to glacial conditions in a few thousand years.
But IMO this study is misleading to speak of “collapse”, if that is its actual language. The melting occurred over a very long period of temperatures higher than now. It was a gradual diminution, not a prompt collapse due to suddenly elevated temperature.
If the Holocene lasts as long as MIS 11, then the southern dome will probably melt at least as much, ie partially, as it did during the previous interglacial, the Eemian of MIS 5, which was warmer & lasted longer than the Holocene has to date, but not as long as MIS-11.

Kenw
June 25, 2014 2:13 pm

milodonharlani says:
June 25, 2014 at 1:55 pm
………
But IMO this study is misleading to speak of “collapse”, if that is its actual language. The melting occurred over a very long period of temperatures higher than now. It was a gradual diminution, not a prompt collapse due to suddenly elevated temperature.
***********
I believe we remember a recent similar situation resulting from the particular meaning of that same word at the other end of the planet.

Taphonomic
June 25, 2014 2:25 pm

Gosh darn that Neanderthal man and his Flintstonemobiles!

spdrdr
June 25, 2014 2:51 pm

Greenland is one of my favourite anti-CAGW examples.
Greenland had a permanent Viking settlement for over 500 years (during the medieval warm period), and there are remains of graveyards and structures under ice sheets today.
They were driven out by (you guessed it!) Climate Change.

June 25, 2014 3:00 pm

spdrdr says:
June 25, 2014 at 2:51 pm
Dunno about under ice sheets, but still under permafrost, yeah, you betcha!

GuarionexSandoval
June 25, 2014 3:01 pm

““This may give us a better sense of what may happen in the future as temperatures continue rising,” Carlson added.”
Like over the past 17 years, Anders? No, temps have fallen. 80 years? No, temps have fallen. How about over the past 1000 years? Fallen. 2000 years? Fallen. 3300 years? Fallen. 8000 years? Fallen. The entire interglacial period up to the present day? A >10,000 year cooling trend, the warm periods becoming progressively cooler, and the intervening cooler periods, progressively colder still, the last one the coldest the planet has been since the last glacial period.

June 25, 2014 3:01 pm

Kenw says:
June 25, 2014 at 2:13 pm
“Collapse” has joined the unprecedented lexicon of how to lie using words as well as statistics.

June 25, 2014 3:09 pm

Taphonomic says:
June 25, 2014 at 2:25 pm
Gosh darn that Neanderthal man and his Flintstonemobiles!
——————————————————————————–
We have the previously unnoticed Neanderthal Industrial Age to blame for partial GIS melting during the Eemian, and it’s H. heidelbergensis’ fault for turning forests into spears and burning them down to cook Irish elk and for warmth without tailored (or maybe any) clothing for the total meltdown of MIS 11. And 800,000 years ago more archaic Homo subspecies had recently invaded Europe. Coincidence? I think not!

spdrdr
June 25, 2014 3:12 pm

Sorry, it is permafrost. I cannot tell the difference between permafrost and an ice sheet, being a tropical sun-lover…

June 25, 2014 3:27 pm

spdrdr says:
June 25, 2014 at 3:12 pm
Good on ya, then!
Color and consistency are give aways, should you ever chose to visit Arctic climes.

charles nelson
June 25, 2014 3:34 pm

Just tell them that Leif and Willis don’t reckon the ‘sun’ has any impact on the earth’s climate.
That should put them in their place!

James Abbott
June 25, 2014 4:18 pm

So it might not be a good idea to keep increasing CO2 concentration in the atmosphere. How would we defend coastal cities from a 5m sea level rise ?

milodonharlani
June 25, 2014 4:25 pm

James Abbott says:
June 25, 2014 at 4:18 pm
So far CO2 increase has been a very good thing. Another 100 ppm or so would be even better for plants & other living things.
The southern dome thawed over tens of thousands of years of elevated temperature. A century of at most one degree higher than during 1977 to 2006 won’t do it.

James Abbott
June 25, 2014 4:35 pm

milodonharlani you put your faith in a rise of only 1C.
We have warmed 0.6C in the last 40 years (NASA GISS).
Also, why do you assume that the elevated temperature will only last a century ?

Vercigenitorex
June 25, 2014 4:39 pm

Yes if the Greenland Ice sheet or Antarctica melted it would be catastrophic. It would also be catastrophic if there were another Toba event or a large asteroid struck the planet.

Luke Warmist
June 25, 2014 4:59 pm

” They acknowledge the need for more widespread coring data and temperature reconstructions.”
…as always, more funding required.

James Abbott
June 25, 2014 5:09 pm

Vercigenitorex – very true. But we have some control over whether the planet continues to warm over the coming centuries but no control at all over a major volcanic eruption or an asteroid strike.

James Abbott
June 25, 2014 5:13 pm
Latitude
June 25, 2014 5:16 pm

James Abbott says:
June 25, 2014 at 4:35 pm
We have warmed 0.6C in the last 40 years (NASA GISS).
==
James..we warmed for the first 30 years because NASA/GISS erased the cooling trend and used a different set of temperature numbers to show temps rising…they did that in 2000…we have not warmed at all since they did that….
..since 2000 there has been no global warming

June 25, 2014 5:16 pm

Jam Abbot says:
“But we have some control over whether the planet continues to warm over the coming centuries”
Yes, “Settled Science”.

Bill Hirt
June 25, 2014 5:40 pm

More Justification Needed for Limiting CO2 Emissions
The scientific basis for limiting CO2 emissions is summarized by two sentences in the “Summary for Policymakers” of the Intergovernmental Panel on Climate Change (IPCC) Fourth Assessment Report (AR4). Both are in a paragraph from Section 2, “Causes of change” of AR4.
“During the past 50 years, the sum of solar and volcanic forcings would likely have produced cooling. Observed patterns of warming and their changes are simulated only by models that include anthropogenic forcings.”
The term “forcings” is the climatologist’s way to quantify the impact of potential contributors to global temperatures in their computer models. Positive and negative forcings denote global warmers and global coolers respectfully.
The first sentence reflects the IPCC climatologist’s assessment that the combination of the sun and volcanic activity would have reduced global temperatures. When they used their estimated “cooling” forcings in the computer model the results, not surprisingly, predicted slight declines in global temperatures over the last 50 years.
As the second sentence explains, rather than “adjust” the sun and volcanic activity forcings, the climatologists assumed the computer model failure was due to a lack of “anthropogenic” green house gases (GHG) primarily CO2 forcings. Raising the computer model “predicted” temperatures to the measured levels required GHG forcings 10 times climatologists estimates for the Sun. It is this level of forcings that makes global temperatures so sensitive to increased GHG emissions and has led to billions spent attempting to reduce their emissions.
It’s not clear why climatologists concluded any potential warming from the Sun was “likely” more than offset by the cooling effects of volcanic ash during the last 50 years. The combination of the two has been largely responsible for many warming and cooling periods for hundreds of thousands of years. Global temperatures during the Medieval Warming Period in 1000-1100 AD were at least as high as current levels. The MWP was followed by cooling, presumably due to some combination of reduced energy from the sun and/or more volcanic ash that lasted until the end of the Little Ice Age of the mid 1800’s.
Much of the temperature increase after 1850 occurred prior to significant GHG emissions. What led climatologists to conclude the combination of the Sun and volcanic activity would reduce rather than increase global temperatures during the last 50 years? Why assume the increase was due to relatively small changes to atmospheric CO2 levels from ~ .031% to .036% during that time period? Particularly since subsequent increases to ~.040% recently haven’t resulted in any significant additional global warming?
The only link between atmospheric CO2 levels and global temperatures was an early assessment (Al Gore (?)) showing global temperatures tended to increase, purportedly in response to higher CO2 levels. However, an article recently published in “Climate of the Past” about East Antarctic ice core studies showed CO2 levels lagged temperature changes by 500 to 5000 years. Obviously increasing CO2 can’t cause global warming if it occurs after the increase.
In conclusion, the hundreds of billions already spent limiting GHG will be dwarfed by the costs associated with future efforts. Climatologists need to do more to justify the need to do so beyond “During the past 50 years, the sum of solar and volcanic forcings would likely have produced cooling.”

Tsk Tsk
June 25, 2014 5:46 pm

James Abbott says:
June 25, 2014 at 5:09 pm
Vercigenitorex – very true. But we have some control over whether the planet continues to warm over the coming centuries but no control at all over a major volcanic eruption or an asteroid strike.
===========================================================
Given sufficient time –say on the order of decades that you warmists wail about– we most assuredly CAN prevent an asteroid strike.
How many billions are you willing to sacrifice to your CO2 monster?

AndyZ
June 25, 2014 5:47 pm

Earth’s orbit? Whatever. We all know it was the Neanderthals use of fire that caused the collapse

June 25, 2014 6:28 pm

Mr. Abbott how much CO2 do we need to take out of the atmosphere to prevent a 5m sea level rise from orbital changes? Will that also make the dark, sooty snow less CO2ey?

June 25, 2014 6:40 pm

James Abbott says:
So it might not be a good idea to keep increasing CO2 concentration in the atmosphere. How would we defend coastal cities from a 5m sea level rise ?
Non-sequitur. The two statements have no relationship. CO2 does not cause sea level rise.
More CO2 is a good thing, as demonstrated by a measurable GREENING of the earth from the current CO2 rise. There is no downside, because there is no evidence of any global harm from that beneficial trace gas. More is better.
If sea levels began to rise to 5 meters, it would mean most of the polar ice has to melt. Since there is no indication whatever that that is happening, Abbott’s statement comes across as a wild-eyed Chicken Little scare.
Relax, Abbott, it was only an acorn.

Mike McMillan
June 25, 2014 8:21 pm

The last interglacial, the Eemian, was a couple degrees warmer than today for around 4,000 years, and yet the Greenland ice cap survived. I think we have some breathing room on this crisis.

JeffC
June 25, 2014 8:54 pm

so they sampling a sand bar and trying to claim they can tell how much ice was on Greenland 400,000 years ago … BS times 10 …

Bill Illis
June 25, 2014 9:47 pm

The southern third of Greenland is too far south to have glaciers. It only has glaciers today because the northern/central region has been accumulating ice for 2.5 million years. Gravity has pushed it down to cover the southern region. And then 100,000 year ice ages ensure it stays in the southern third …
… except when an interglacial period lasts more than 15,000 years. It just takes a certain amount of time to melt out all that ice at today’s temperature levels.
The interglacial at 400,000 years ago was 25,000 years long and temperatures were similar to today. Same with the interglacial 800,000 years ago. In both these interglacials, the southern third of Greenland melted out and small trees even grew there.
The current interglacial is projected to be the longest one yet. Lasting at least 52,000 years morel and, more likely, 125,000 years. Far northern summer solar insolation will decline by a tiny amount (0.5 W/m2) in the next 2,000 years, leaving it well above the limit needed to melt the snow in the summer on non-glaciated land. It will then go back up again and stay above the limit needed to melt the snow in the summer for the next 50,000 years after this. It will be touch and go at this time, but solar insolation will then increase again after this time, staying high until 125,000 years from now.
The southern third of Greenland will not have glaciers in about 2,000 or 3,000 years. The central part will melt out over the next 20,000 years.
It is just what the Milankovitch cycles project. We can be reasonably accurate about this for as much as 5 million years out after which there are too many uncertainties.
Nobody will be around to check this forecast, but it is what it is.

Neil
June 25, 2014 9:53 pm

James Abbott asks, “How would we defend coastal cities from a 5m sea level rise ?” – if such a thing were to happen for whatever reason.
The answer to your question is “Dikes”. When I lived in Holland I was 8 metres below sea level, so it’s already existing technology.

June 25, 2014 10:20 pm

Forget Milankovitch, the real problem is dark energy flux. Just divide by the square root of minus 1. Get a term that is equal even though it differs over a range of 2. Mathematics is the art of making two different things the same.

arfurhaddon
June 25, 2014 11:32 pm

“…as temperatures continue rising”???
Shouldn’t that be if or when?

phlogiston
June 26, 2014 1:13 am

This was an exceptionally long warm period between ice ages that resulted in a global sea level rise of about 6-13 meters above present.
So let’s get this straight.
Longer duration of an interglacial means more sea level rise.
So it is normal to see sea level rise throughout an interglacial.
BUT [scary organ music in background]
Current sea level rise is different.
It is not natural.
Oh no.
It is because of our SINS! [Wails of religious angst and self-loathing]
It can only be CO2.
Human activity is the only possible cause of climate change.
How long will these mendacious morons get away with peddling this crap?

Stephen Richards
June 26, 2014 1:21 am

James Abbott says:
June 25, 2014 at 5:09 pm
Vercigenitorex – very true. But we have some control over whether the planet continues to warm over the coming centuries
Oh oh the man behind the curtain has appeared. and how do we have control over the climate then James ?? You have some magic extremely high powered control machine do you ?
Oh sorry your second name is Jesus. Which lunatic asylum did you escape from ?

Stephen Richards
June 26, 2014 1:22 am

How long will these mendacious morons get away with peddling this crap?
For as long as the other mendacious morons in government need the taxes to spend.

June 26, 2014 1:39 am

I would like to chime in with others who have noted that this is a misuse of the word “collapse.” Correct usage of the word suggests speed and suddenness, in its primary definition: “To break apart and fall down suddenly.” It is a stretch to use it for something that takes thousands of years to happen.
You have to scratch your head in wonder, when a worst-case scenario is a rise of a couple inches in a lifetime. I have built sand castles at the beach that could withstand waves that tall.

charles nelson
June 26, 2014 2:07 am

I think we’re witnessing the ‘collapse’ of the CAGW cult.
Ok…well more like it’s agonisingly slow decline!

charles nelson
June 26, 2014 2:12 am

its agonisingly slow decline…tsk.

phlogiston
June 26, 2014 3:04 am

Bill Illis says:
June 25, 2014 at 9:47 pm

The current interglacial is projected to be the longest one yet. Lasting at least 52,000 years morel and, more likely, 125,000 years. Far northern summer solar insolation will decline by a tiny amount (0.5 W/m2) in the next 2,000 years, leaving it well above the limit needed to melt the snow in the summer on non-glaciated land. It will then go back up again and stay above the limit needed to melt the snow in the summer for the next 50,000 years after this. It will be touch and go at this time, but solar insolation will then increase again after this time, staying high until 125,000 years from now.
Tzedakis in his 2012 paper said that:
“The glacial inception during Marine Isotope sub-Stage 19c, a close analogue for the present interglacial, occurred near the summer insolation minimum, suggesting that the interglacial was not prolonged by subdued radiative forcing.” (my bold)
http://www.nature.com/ngeo/journal/v5/n2/abs/ngeo1358.html
This contradicts your assertion that “subdued radiation forcing” will prolong the current interglacial.
Its a nonlinear system. The absolute values of insolation are not the be-all-and-end-all that you make them out to be.
Note also – why did the MPR happen? We are over the long term in a period of deepening glaciation. From no glaciation, to interglacials with 40k year spacing, to 100k year spacing, to predictably a future of uninterrupted glaciation.
A 125k year interglacial is very unlikely in this context.

James Abbott
June 26, 2014 3:07 am

Ignoring dbstealey’s C18th take on science…
Tsk Tsk you say
“Given sufficient time –say on the order of decades that you warmists wail about– we most assuredly CAN prevent an asteroid strike.”
Tell us how please ?
Also, we know the orbits of all the large asteroids. Work is ongoing on tracking the smaller ones now – and those would not cause a global disaster. The bigger immediate danger is comets. We might have just a few years warning of an impact from a newly discovered large comet coming in from the outer solar system.
But the risk of that is very small compared to the risk of just allowing CO2 concentration to keep increasing. Stephen Richards – we have control over that – which is my point. Or do you think the rise in concentration since the Industrial Revolution is natural ?

richardscourtney
June 26, 2014 3:52 am

James Abbott:
I am genuinely curious.
At June 26, 2014 at 3:07 am you assert

But the risk of that is very small compared to the risk of just allowing CO2 concentration to keep increasing. Stephen Richards – we have control over that – which is my point. Or do you think the rise in concentration since the Industrial Revolution is natural ?

Please explain
1.
What is the “risk of just allowing CO2 concentration to keep increasing”?
2.
Whether or not the rise in concentration since the Industrial Revolution is natural, how do we “have control over that” when “no systematic analysis has published on the relationship between mitigation and baseline scenarios”?
3.
The fact that nobody knows the relationship between mitigation and baseline scenarios was published by the IPCC in Chapter 2 from Working Group 3 in the IPCC’s Third Assessment Report (2001). Nobody has made such a publication since, so how do you know “we have control over that” when nobody else does?
4.
Why have you not published your unique knowledge of how “we have control over that” when you claim there is “risk of just allowing CO2 concentration to keep increasing” unless – of course – you think the “risk” is trivial?
Thanking you in anticipation of your clarifications
Richard

Alan the Brit
June 26, 2014 4:10 am

There seems to me to be a big gap between the atmospheric CO2 “causing” Climate Change, & proving it. The only argument seems to be “but what else can it be?” which has much to be desired on a scientific front, especially when NOBODY has described what the natural variability of climate actually is! Who will hold these AGW/CC idiots to account in the long run, or will they just be handsomely pensioned off into oblivion to be forgotten with the “best available science at the time” meme ringing in our ears? This reminds me of crying witch! Better get the ducking stool ready along with some bundles of sticks for the fire!

Ah. . . Clem
June 26, 2014 5:42 am

James Abbott says:
June 25, 2014 at 5:09 pm
Vercigenitorex – very true. But we have some control over whether the planet continues to warm over the coming centuries but no control at all over a major volcanic eruption or an asteroid strike.

Who is we James? ISIS? The Chinese? Subsaharan Africans? The Yanomami? Popol Vuh? Global Warming is a First World problem dreamed up by half educated socialist globalists who are totally blind to the second and thiird world social, economic, nationalist and religious extremist threats staring them squarely in the face.

Kenw
June 26, 2014 5:58 am

“Ah. . . Clem ”
perhaps I am the only other one who knows where that name comes from…..

June 26, 2014 6:59 am

Reblogged this on This Got My Attention and commented:
Whoa, Nelly! The Greenland icesheet collapsed WITHOUT man-caused global warming 400,000 years ago. How will the alarmists work this into their models?

david
June 26, 2014 7:11 am

It would have been illuminating if they had shown data for other interglacials so as to judge the MIS 11 sedimentation events comparatively. To refer to MODELS of anything just diminishes further what they have to say. Who reviewed this for Nature – where all the trouble starts. How long before the politicians latch on to this as “evidence” for a catastrophic future. 0 out of 10 I`m afraid, and hardly scientific.

tadchem
June 26, 2014 7:35 am

Teriffic! Now we have empirical data regarding the consequences of global warming and a global MSL rise both 400,000 Ya and 125,000 Ya – two periods remarkable in the fossil record for a complete dearth of global catastrophe and the mass extinction of absolutely nothing.
So the AGW alarmists want us to invest trillions of dollars/euros/yuan/shekels/kroner/etc. in a futile effort to prevent – nothing.

June 26, 2014 7:43 am

James Abbott says:
June 26, 2014 at 3:07 am
Or do you think the rise in concentration since the Industrial Revolution is natural ?
+++++++++
No, I think the rise of CO2 since the Industrial Revolution is meaningless, except as noted for the added growth of plants.

June 26, 2014 8:40 am

“Reblogged this on This Got My Attention and commented:
Whoa, Nelly! The Greenland icesheet collapsed WITHOUT man-caused global warming 400,000 years ago. How will the alarmists work this into their models?”
1. It was warm.
2. The cause (forcing was not C02)
“The climate 400,000 years ago was not that much different than what we see today, or at least what is predicted for the end of the century,” said Anders Carlson, an associate professor at Oregon State University and co-author on the study. “The forcing was different, but what is important is that the region crossed the threshold allowing the southern portion of the ice sheet to all but disappear.
You see a firm today set by an arsonist. You look back in time and you find a fire 100 years ago set in the exact same place. It was set by lightening. The fact that both arsonists and lightening
can cause fires means you have to take care in doing attribution. Finding a fire in the past set by lightening tells you NOTHING about the fire set today by an arsonist.
How will it be worked into the models? Well, one thing that is hard to model is loss of ice.
But now they have a way of testing various approaches.

Robert Kral
June 26, 2014 10:03 am

What is the physical evidence to support the contention that the previous warming was caused by variations in the Earth’s orbit? Isn’t it possible it was due to variations in solar activity?

James at 48
June 26, 2014 1:24 pm

That was well into the Pleistocene. And we worry about our little blip on the back of a wimpy interglacial that teeters on the edge of the next onset of ice.

Jaakko Kateenkorva
June 26, 2014 1:37 pm

“The sediments are only deposited when there is significant ice to erode the terrain. The absence of terrestrial deposits in the sediment suggests the absence of ice.”
And yet there is plenty of smooth granite bedrock without sediment in the wilderness. Teachers used to pin that on the last glacial period.
Wondering also, now when the Glacier Girl has been removed, what other sediments than terrestrial deposits did they discover in Greenland.

June 26, 2014 4:26 pm

My wife has a Master’s degree in Education and was a Middle School Principal for 20+ years, and I can out-spell and out-write her and 99% of her [gov’t educated] teachers. And science? Fugedaboutit. So I get endless pleasure out of reading what a graduate with an English degree wrote:
You see a firm today set by an arsonist… It was set by lightening. …lightening, lightening, lightening. So it wasn’t a typo.
Anyway, that off my chest, Mr. Abbott opines that the risk of an asteroid strike is very small compared to the risk of just allowing CO2 concentration to keep increasing.
I challenge Mr Abbott to list evidence of any global harm due to the rise in that trace airborne fertilizer. If there is no verifiable, measurable ‘harm’ due to more CO2, then CO2 is ‘harmless’, no?
Abbott asks, do you think the rise in concentration since the Industrial Revolution is natural ?
Of course it is natural. A little of it is produced by human activity, which is entirely natural. CO2 is also beneficial to the biosphere. There would be more people starving today if we did not emit CO2. Literally. Maybe Mr Abbott could expound on why he would prefer starvation.

Vercigenitorex
June 26, 2014 7:35 pm

Ah. . . Clem ”
perhaps I am the only other one who knows where that name comes from…..
I’d like to recommend “Wall of Science”
I beleive that is near Dutch Elm Street

milodonharlani
June 26, 2014 7:49 pm

Steven Mosher says:
June 26, 2014 at 8:40 am
Among the many objections to your hand-waving special pleading is the fact that 800,000 years ago the southern dome had also melted away. And that it partially melted during the Eemian interglacial.
The simplest & best explanation is that during the past 2.6 million years earth cools & warms in natural cycles. The Holocene has been cooler than both MIS 11 & the Eemian, so natural “catastrophic global warming” is perhaps less likely now than 400 Ka & 100 Ka, but orbital mechanics suggest that the 400 Ka & 800 Ka interglacials resemble the Holocene, so the jury is still out.
The one potential “forcing” that can categorically be excluded is man-made CO2.

milodonharlani
June 26, 2014 7:50 pm

Jaakko Kateenkorva says:
June 26, 2014 at 1:37 pm
Glacier Girl was taken out of ice nowhere near bedrock.

george e. smith
June 26, 2014 9:15 pm

Well Greenland fell apart 400kyrs ago. What a tragedy.
Oh wait on; not to worry. It all grew back again, and it’s ok now.
Wow for awhile there I was a bit concerned.
Frankly, I think the study of climate, particularly in the past, to be a gigantic waste of time and money. Can’t do anything about it anyway.
Just try getting ten people from ten different countries to agree completely on when and where to have a meeting.
Now try that for seven plus billion people; all to agree to do something.
Don’t mind looking at next week’s weather. But climate 30 years ago, or 30 years from now is of no value whatsoever.

The definition Guy
June 27, 2014 12:06 am

Taphonomic says:
June 25, 2014 at 2:25 pm
Gosh darn that Neanderthal man and his Flintstonemobiles!
——————————————————————————–
Fred drove a zero emission car made of stone, don’t blame him. It was Barney Rubble in his wooden Barneymobile that led to the meltdown. By taking a tree out of the carbon cycle to produce his vehicle, Barney removed a co2 absorber from the system and when he eventually had to scrap the car, after the incident involving Bam Bam and the Algoresaurus, the junk yard burned the chassis and carbon dioxide was released back into the atmosphere.
So it was Barney, not Fred, who should bear the blame. Fred was innocent!

tty
June 27, 2014 4:35 am

This kind of study is actually much shakier than it might seem from the press release. Studies of maritime deposits can only tell about glaciers that reach the coast. Once the icecap has retreated inland it becomes effectively invisible in the maritime record.
So they can potentially tell which parts of Greenland had ice-free coasts, but not the conditions inland (where icecaps can actually become thicker when they can no longer calve into the sea). To complicate things further currents in the Eirik Drift area change greatly between glacials and interglacials.
Incidentally for Greenland ice to raise sea-level by six meters requires almost complete deglaciation, something we know from periglacial deposits in northern Greenland has not happened for about 1.8 million years.
However these big figures are needed to explain the vastly overblown sea-level rise figures in vogue for MIS 11. These are due to the exceptional length of MIS 11 which allowed isostatic adjustment to proceed much further than during other interglacials, a fact that is almost always ignored by “climate scientists” who do not understand geology. These high figures are invariably from tectonically unstable areas, or areas in the “forebulges” of the Eurasian or Laurentid icecaps (like Bermuda or the Bahamas). Actually evidence from tectonically stable areas far from any icecap, like South Australia, strongly suggests that sea-levels in MIS 5 and MIS 11 were approximately the same and about 2-5 meters higher than at present.

June 27, 2014 10:53 am

“The climate of 400,000 years ago was not that much different than that of today”
Anders Carlson, co-author
<<<<<<<<<<<<<<<<<<<<<<<>>>>>>>>>>>>>>>>>>>>>>>
The climate was much warmer then than todays: tropical and sub-tropical fauna and flora in England. Carlson’s goof is the sort of drivel that you get from the alarmists. He wants to panic people into thinking that catastropic melting of the Greenland ice cap is just around the corner.The climate scam continues unabated.

June 27, 2014 11:13 am

Oh yes, do not believe any reports about rising sea levels. They are steady, but fabricating a rising sea level has become a minor industry with the alarmists. Sea level trend is flat and has been some 15-20years: see the NOAA mean sea level trends for the west coast and Gulf coast tidal guages.

phlogiston
June 27, 2014 11:39 am

Steven Mosher says:
June 26, 2014 at 8:40 am
You see a fire today set by an arsonist. You look back in time and you find a fire 100 years ago set in the exact same place. It was set by lightening. The fact that both arsonists and lightening
can cause fires means you have to take care in doing attribution. Finding a fire in the past set by lightening tells you NOTHING about the fire set today by an arsonist.

Going down the logic road is ill-advised since logic has to be suspended for CAGW to work. Aristotle, Bacon, Popper etc are not the friends of CAGW.
Look, during the Holocene there have been about 20 episodes of multidecadal warming very similar to the one from 1970-2000. These are known to be caused by the completely normal and expected oscillation of a dissipative chaotic-nonlinear climate system emerging as multidecadal-centennial shifts in ocean currents. All this in the Holocene during most of which temperature has been slowly declining and at the same time CO2 slowly rising:
http://rogerfromnewzealand.files.wordpress.com/2010/01/holocene_delta_t_and_delta_co2_full2.jpg
So now in the 20th century we get upswing number 20. Remind me again how we get to “this one has to be the exception due to CO2”??
CAGW attempts at logic to deny climate history takes forms such as:
“An arsonist starts a fire. Over in Florida lightning set fire to a tree. So CO2 causes global warming.”
or
“A man is found with a knife in his back. But my gran used a kitchen knife to slice carrots. Ergo – CO2 causes global warming”.
This is not logic but rage and denial against logic which is – correctly – perceived as a threat.

June 27, 2014 2:32 pm

If you have got to copy & paste, then even that is worth it as this kind of science shows, at least as far as I can see, that there is absolutely no correlation between T and CO2 that suggests that CO2 is the main driver for T (Temperature)
Ice Core Data from Vostok, Siberia
http://www.geocraft.com/WVFossils/temp_vs_CO2.htmlBased on the analysis of entrapped air from ice cores extracted from … ( approximately 0.6° C, globally) that appears to have occurred over the past century. … slightly and surface temperatures have ceased warming — even as CO2 concentrations have continued to increase (3). … Carbon Dioxide -vs- Temperature Graphs: …

June 27, 2014 2:45 pm

Sorry, my fault. – Try the one below in stead;
http://www.geocraft.com/WVFossils/temp_vs_CO2.html

June 27, 2014 2:54 pm

And then there is this one from the other end of the Earth;
http://mclean.ch/climate/Ice_cores.htm

July 9, 2014 6:12 am

Well, I may not agree with the stance of this page & many of the other commenters, but I will give ya’ll this much.. The manner in which you (the blogger) write about it, as well as the content & attitude of the comments here, are a breath of fresh air, as far as its done with civility/thoughtfulness/decorum/& a certain understanding & respect for science/scientists. So bravo for that! 🙂
(I read an anti-climate change article on the Tea Party ‘News’ Network, & the manipulative misleading juvenile simple-minded & irresponsible writing in the article, & the long stream of horrifying ignorant mean-spirited & irrational comments, were all jst terribly depressing. I seriously felt a bit freightened b,,,,,,,,,–zy the idea that those people have any influence in America’s policy making.)
Other than that, my only other comment is re: sea level rise…. So, whether it be man-made or natural, if the sea level rises, shouldn’t we prepare for this..?? I mean, there are A LOT of people who either dont know or dont believe this is happening (mostly due to the more irrational skeptic voices telling them it will all be fine & things arent/wont change). And, unlike the last time this occurred, we now have a multitude of major metropolises inhabited by ever increasing populations, which are seaports or coastal cities.. And it may not sound like much (4-8ft), but thats enough to do significant damage, & even submerge cities/islands/etc.
There are a bunch of problems involved if this happens – relocating people/jobs/industry, financial burdens, etc.. And theyre only gonna get worse the longer we wait to take action. But the continued debate is holding up the process & hindering us frm working on solutions to cope with this. Its frustrating, to say the least. :/

RACookPE1978
Editor
July 9, 2014 7:48 am

Little♥Desert♥Flower says:
July 9, 2014 at 6:12 am
Well, I may not agree with the stance of this page & many of the other commenters, but I will give ya’ll this much.. The manner in which you (the blogger) write about it, as well as the content & attitude of the comments here, are a breath of fresh air, as far as its done with civility/thoughtfulness/decorum/& a certain understanding & respect for science/scientists. So bravo for that! 🙂
(I read an anti-climate change article on the …
Other than that, my only other comment is re: sea level rise…. So, whether it be man-made or natural, if the sea level rises, shouldn’t we prepare for this..
There are a bunch of problems involved if this happens – relocating people/jobs/industry, financial burdens, etc.. And theyre only gonna get worse the longer we wait to take action. But the continued debate is holding up the process & hindering us frm working on solutions to cope with this. Its frustrating, to say the least. :

Well, actually, the natural rise of sea levels by the year 2100 that you so greatly fear is not going to be stopped by anything you require doing.
And the penalty for immediately trying to limit CO2 releases – which will do nothing to stop, slow, reduce, or limit the sea level rise of 4 feet (actually only about 2 feet by 2100 years is probable) is the immediate murder of millions each year for the next 86 years, the immediate harm of billions each year for the next 86 years by restricting their energy use and increasing their energy costs and reducing their energy reliability. Your “Precautionary Principle” requires we immediately hurt billions of innocents today and for years to come not only to gain “nothing” now or in the future; but only to require actions which could at best only trivial reduce the probability of a result (increasing temperatures and increasing CO2 levels) that will not only do no harm, but are beneficial in and of themselves!
So, who does gain by a world government by harming billions for 86 years and killing millions each year? Who does gain power, money, influence, control, domination, and prestige? Who controls the states’ grants, funds, research, and promotions? Who are the anonymous people who are controlling your emotions to give them power? Who gains from their increase of their power?
What “solutions” are YOU proposing to increase the world’s energy supplies and resources to improve lives? Everything I see is the demand that “we” do something that harms innocents and empowers the government and its enabling propagandists and priests.
Oh, by the way, what part of “anti-climate change” do you think any rational person believes in? Those who believe as their stated government-academic-bureaucratic religion that restricting man’s CO2 levels now will change the world’s future climate are the ones who deny climate change.