Researchers show that high ancient shorelines do not necessarily reflect ice sheet collapse millions of years ago
From the Canadian Institute for Advanced Research:
For decades, scientists have used ancient shorelines to predict the stability of today’s largest ice sheets in Greenland and Antarctica. Markings of a high shoreline from three million years ago, for example – when Earth was going through a warm period – were thought to be evidence of a high sea level due to ice sheet collapse at that time. This assumption has led many scientists to think that if the world’s largest ice sheets collapsed in the past, then they may do just the same in our modern, progressively warming world.
However, a new groundbreaking study now challenges this thinking.
Using the east coast of the United States as their laboratory, a research team led by David Rowley, CIFAR Senior Fellow and professor at the University of Chicago, has found that the Earth’s hot mantle pushed up segments of ancient shorelines over millions of years, making them appear higher now than they originally were millions of years ago.
“Our findings suggest that the previous connections scientists made between ancient shoreline height and ice volumes are erroneous and that perhaps our ice sheets were more stable in the past than we originally thought,” says Rowley. “Our study is telling scientists that they can no longer ignore the effect of Earth’s interior dynamics when predicting historic sea levels and ice volumes.”
The study, published online in Science on May 16, was a collaboration that included CIFAR Senior Fellows Alessandro Forte (Université du Québec à Montréal) and Jerry Mitrovica (Harvard), and a former CIFAR-supported post-doctoral fellow Rob Moucha (Syracuse).
“This study was the culmination of years of work and deep collaboration by researchers in CIFAR’s program in Earth System Evolution,” explains Rowley. “For this study, each of us brought our individual expertise to the table: Rob and Alex worked on simulations of Earth’s mantle dynamics, Jerry provided calculations on how glaciers warp Earth’s surface, and I shaped our understanding of the geology of the landscape we were looking at. This study would not have been possible without CIFAR.”
The team studied the coast from Virginia to Florida, which has an ancient scarp tens of metres above present-day sea level. Until now, many research groups have studied this shoreline and concluded that during a warm period three million years ago, the Greenland, West Antarctic and a fraction of East Antarctic ice sheets collapsed, raising the sea level at least 35 metres. But the new findings by Rowley and his team suggest that these ice sheets, particularly the East Antarctic Ice Sheet (the world’s largest), were probably more stable.
To do their study, the team used computer simulations to follow the movement of mantle and tectonic plates that occurred over time. Their prediction of how the ancient shoreline would have developed over millions of years matched what geologists mapping this ancient coast have observed. The next steps for the team are to try to make accurate predictions in other locations around the world.
“The paper is important because it shows that no prediction of ancient ice volumes can ever again ignore the Earth’s interior dynamics,” explains Rowley. “It also provides a novel bridge between two disciplines in Earth science that rarely intersect: mantle dynamics and long-term climate. It is the kind of study that changes how people think about our past climate and what our future holds.”
Source: http://www.cifar.ca/ancient-shorelines-ice-sheets-stability
h/t Dennis Wingo
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Dynamic Topography Change of the Eastern United States Since 3 Million Years Ago
David B. Rowley, Alessandro M. Forte,Robert Moucha, Jerry X. Mitrovica,
Nathan A. Simmons, Stephen P. Grand
Abstract
Sedimentary rocks from Virginia through Florida record marine flooding during the mid-Pliocene. Several wave-cut scarps that at the time of deposition would have been horizontal are now draped over a warped surface with a maximum amplitude of 60 m. We modeled dynamic topography using mantle convection simulations that predict the amplitude and broad spatial distribution of this distortion. The results imply that dynamic topography and, to a lesser extent, glacial isostatic adjustment, account for the current architecture of the coastal plain and proximal shelf. This confounds attempts to use regional stratigraphic relations as references for longer-term sea-level determinations. Inferences of Pliocene global sea-level heights or stability of Antarctic ice sheets therefore cannot be deciphered in the absence of an appropriate mantle dynamic reference frame.
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IOW eons ago when nothing was being measured we had no measurements and all our guesses were wrong.
and all our money was wasted.
Geologic time scales confound humanity. Considering where the continents were 55 million years ago, and where they were 3 million years ago and the 300,000 years current humans have been around, it is no surprise we don’t understand all the parameters. And maybe the timelines and assumptions I have referenced are also wrong. We take evidence and create a hypothesis that lasts until other evidence is found and we have to formulate a new hypothesis. But sometimes people are so invested in the current hypothesis, it takes a lot of evidence to change the hypothesis (CAGW). Great article.
Well, YES. I’ve been wondering when people would take into account isostatic rebound!
“Our study is telling scientists that they can no longer ignore the effect of Earth’s interior dynamics when predicting historic sea levels and ice volumes.”
The fact that scientists WOULD ignore tectonics (the effect of interior dynamics) is astounding! Typical of agenda-driven oversimplifications…!
Wayne, I think it’s more like governments invested big time because they saw the potential to govern a crisis for their benefit. Not sure about the history of the planet, but historically it has always been the goal of the elite to rule over the rest of us. Oligarchy comes in many forms and they are mostly bad.
http://en.wikipedia.org/wiki/Post_glacial_rebound
“Viso-elastic….mantle may take many thousands of years to reach equilibrium….[aka] the ‘glacial isostatic adjustment’ also involves downward, horizontal land movements….[as well as] sea level, gravity field and rotational changes.” I’ve got a “Geo-nuclear” tab full of articles at my website on these NON constant climate changing forces.
http://pubs.usgs.gov/gip/dynamic/himalayan.html
It’s only an upward movement of 1 cm/year…but the Himalayan Mountains would require a substantial internal force for any vertical movement. Now if we accept these kinds of movements, can Plato’s Atlantis be objectively discussed ? In this Universe, noting is constant and equilibrium is an illusion.
This is good news indeed – except for econuts, as it doesn’t strengthen the narrative of their apocalyptic religion.
They have found fossils atop of mount Everest
Geologists have known rise-fall cycles of 2-10m throughout “stable” geologic times is the norm since oil well logs were invented. The seas were not moving – the crust was!
But geologists aren’t “real” scientists who see computers as more truthful than observations, so their opinion on current processes just doesn’t count.
sorry marine fossils
Here’s all the models used by the IPCC for SLR until 2300, or the next 300 years.
http://rsta.royalsocietypublishing.org/content/364/1844/1709/F4.large.jpg This is the projection for SLR from Antarctica, all negative and Greenland all positive.
This covers 89% and 10% of the planets ice mass or total of 99%. So with this increased precipitation we have to ask where is any dangerous SLR to come from for the next 300 years?
The last earthquake in the Quebec/Ontario region about five or six years ago was the result of the earth rebounding from the weight of the earlier ice sheet covering Canada. It certainly stands to reason the interior of the planet has been dismissed despite the evidence.
Mike jarosz say: at 7:31 pm
“Wayne, I think it’s more like governments invested big time because they saw the potential to govern a crisis for their benefit. Not sure about the history of the planet, but historically it has always been the goal of the elite to rule over the rest of us. Oligarchy comes in many forms and they are mostly bad.”
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Agree, but would add something that is an order of magnitude more evil,…these so called elite see the opportunity with AGW to rid the planet of useless eaters to attain a sustainable human population level proportionally commensurate with those of a well run wild life conservation park.
A tip of the hat to the research team, this is what science is suppose to be about. It’s refreshing to see an honest study with no preconceived or predetermined conclusion.
“…Good news: World’s biggest ice sheets likely more stable than previously believed – upsets previous estimates of melting and sea level…”
Better news: The abstract never mentioned the words “global warming” or “global climate change” – that means that it won’t show up in the next John Cook “97% paper”. Even if it had been used by using “global sea-level height”, it would have fallen into the group that stated no position on AGW.
The consensus falls, one paper at a time…
This makes so much sense. I remember hearing a Lindzen lecture years ago wherein he talked about how continents rise and fall. He said something to the effect that how can we be so sure that it’s the seas that will rise? What if it’s a continent that will fall because of some isostatic movement, or some event that happens on the other half of the world? It was an epiphany for me. I vaguely remembered the principle of isostasy and looked it up again. It made perfect sense, and so do these scientists’ findings.
Otter says: May 18, 2013 at 7:11 pm
Well, YES. I’ve been wondering when people would take into account isostatic rebound!
They do already; A GIA adjustment of 0.3 mm/year is added to all sea level rise measurements.
Can’t quite see the logic in that, surely it is nett sea level rise which matters, rather than trying got take into account estimates of ocean deepening as the land rebounds. (is it measured, or just theorized? I don’t know)
The best estimate from the most stable tidal guages gives us a sea rise figure of 1.5 mm per year, (including the GIA adjustment), and I figure the nett rise of 1.2 mm/year is probably close to reality, as there are a huge number of adjustments and jerry rigging going on to make satellite figures work.
http://en.wikipedia.org/wiki/Permanent_Service_for_Mean_Sea_Level
http://ilrs.gsfc.nasa.gov/docs/GRASP_COSPAR_paper.pdf
Here is why east coast USA is worried … they are actually sinking:
http://geology.gsapubs.org/content/37/12/1115.abstract
Now, should we build levies, or try to stop the ocean rising?
Yes, you, up the back … Canute isn’t it? … Yes, what do you think?
RE: Mike jarosz says:
May 18, 2013 at 7:31 pm
While I fear you may be right about cynical people bailing out on the concept of freedom for all, and hoping to be sly enough to wind up on the up-side of an oligarchy, I feel there is another segment of the Alarmist population that is simply insecure, and seeks to end their insecurity with a somewhat absurd belief they can control the weather.
In actual fact we can no more control the weather by sacrificing our wealth than we can control a volcano by sacrificing virgins. However it apparently makes some feel more secure, (unless they happen to be a virgin.)
I can remember the first time I heard the idea of sacrificing a virgin. I was a small boy looking at a New Yorker cartoon, and was so puzzled I asked my Dad to explain it to me. After he explained the idea, I failed to get the joke. In fact, I was downright indignant. I felt that I sure wouldn’t stand for having perfectly good virgins chucked into a volcano. I’d rush in and rescue the girl, even if it meant I had to chuck a couple witch doctors into the volcano. (I was so young and innocent that the girl’s virginity would have been safe with me.)
I felt very glad I did not live in a culture that was so stupid. However the passage of a half century has changed my culture, and perhaps we now may be so stupid.
Certain Alarmists need to face the fact there is no cure to certain insecurities. We cannot control the weather, sea levels, volcanoes, earthquakes, and the depressing fact that, in the end, we all die. Sorry, you fellows, that’s just the way creation got created. Would you rather you hadn’t been created at all? If so, you are missing a lot of beautiful things. I myself am rather enjoying the roller coaster ride.
Another battle between Geophysicists and Geographers. The Laws of Physics versus The Gods of Astrology. The IPCC is a ‘Social’ Geographer Society; just listen and look around the 5-Star Hotel bar at the ‘Plenary Meetings’ where the ‘Intelligencia’ convene to ‘exchange’ lofty ‘scientific’ notes. Hoy hoy.
“… you, up the back … Canute isn’t it? … Yes, what do you think? [MarkX]
A Voice from the back of the room: Are you talking to me? Are you talking to me??? Are you talking to ME?! AHEM! They caaaaaalll meeee, KING Canute! [;)]
Actually, Dr. Krauthammer (and likely others) mischaracterize the venerable monarch. At low tide, King Canute placed his throne just below the high tide line, “O mighty ocean, stay back!” (or something close to that) he intoned. Then, he waited. When the waters were swirling around his feet, he stood up. Turning to his people he said sternly, “No one, not even a king, can command the tide. Only God can do that.”
Lesson: Don’t put your faith in mortals. Not even kings.
(That is, Canute didn’t believe he could control the tide.)
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Re: Stuart L. (Little? Is that YOU, Stuart??! Watch out for the bad cat!)’s reminder about marine fossils on the top of Mt. Everest, both King Canute and I agree that they most likely got there by a Great Flood. Yes, I firmly believe the flood, upon which floated the 8 remaining people and enough animals to repopulate the earth, covered the entire earth. While one may choose not to believe it happened, to assume a priori that it did not is not rational — it is simply a philosophical choice. You either believe it or you do not. You cannot prove it did not occur.
I believe the evidence found all over the planet is stronger for a Great Flood than the evidence for its having not occurred.
A skeptical mind is not a closed mind, it is a careful mind, open to whatever the evidence shows.
Are you telling me the ground is not fixed in place ? whoever heard of the ground moving ?
Caleb, what a great post. Thanks for being so candid. I think that, even now, a virgin who was not your newly wed wife would be safe with you. You have integrity.
I just have to add one thing to your insightful post, re: “the depressing fact that, in the end, we all die.” For me, while it is depressing when those I love die, that I will, one day, die, is a joyful thought. The day I gaze on my last sunrise will be my loveliest day. THE BEST IS YET TO COME!
Yes, Master of Puppets (at 9:31PM – “The IPCC is a ‘Social’ Geographer Society; just listen and look around the 5-Star Hotel bar at the ‘Plenary Meetings’ where the ‘Intelligencia’ convene to ‘exchange’ lofty ‘scientific’ notes.”), the IPCC is merely a den of corruption and hypocrisy. It reminds me of Sergei Kourdakov’s* description of the after-party in the Soviet Union around 1971. Kourdakov, around age 19, a top Komsomol (or Communist Youth) leader, was given the high honor of attending a major Communist Party meeting and the exclusive party afterward.
What he saw opened his eyes to what Communism is all about: a dictatorship of a drunken, gluttonous, greedy, elite. He, a true believer in communism, was shocked at what he saw in that private banquet hall. The IPCC is essentially a communist club. Only those whose consciences have been seared can stand to remain a part of it. Kourdakov eventually defected to Victoria, B. C., Canada around 1973. Within 2 or three years, Quebec communists assassinated him. [from Kourdakov’s book, The Persecutor, Spire Books (1976?) — story of how he, a KGB agent, went from persecuting Christians to becoming one himself. He was only about 24 years old when he died.]
Caleb writes of: “… the idea of sacrificing a virgin.”
Or perhaps the gods might be satisfied with the sacrifice of just the virginity thereof, and not the whole virgin???