Land motion drives varying rates of sea level along the US East Coast


From Science Magazine

Dec 20, 2018

Along the US East Coast, the Earth’s continued response to the end of the last ice age explains variances in relative sea level rates

Chestnut Hill, Mass. (12/20/2018) – Along the East Coast of the United States, relative sea level change does not happen uniformly between Maine and Florida.

Data have shown that sea level rise in the Mid-Atlantic region surpassed changes in relative sea level along the coastlines of the South Atlantic and the Gulf of Maine. A team of researchers took a look back at historical data through new analytical methods to pinpoint the reason behind the different rates of sea level change.

Assessing data from a range of sources and previous studies, the team concluded that the movement of the earth – referred to as vertical land motion – is the dominant force behind variations in rates of sea level rise up and down the East Coast, the team reports today in the journal Nature.

Across the past century, records indicated that sea level rise has varied – from approximately 1.5 feet along the shores of the Chesapeake Bay in Virginia and the beaches near Cape Hatteras, North Carolina, to approximately one foot near New York City and Miami. Along the coast of Maine, sea level rose only about a half a foot.

The team found that vertical land motion is the primary factor influencing the spatial variability in relative sea level rates, explaining 75 percent of the observed variation along the East Coast, according to the report, titled “Origin of spatial variation in the US East Coast sea-level trends during 1900-2017.” More than two-thirds – or 69 percent – of the observed vertical land motion is due to ongoing effects from the last ice age.

“This ice age effect is the largest in Maryland, Virginia, and North Carolina,” said Boston College Assistant Professor of Earth and Environmental Studies Carling C. Hay, a co-author of the report with colleagues from Woods Hole Oceanographic Institution, Harvard University, Tufts University, and Atmospheric and Environmental Research, Inc.

“The remaining sea level trends that cannot be explained by vertical land motion also exhibit significant structure, with rates of sea level rise increasing from northern Maine to southern Florida,” Hay said. “This spatial structure is consistent with patterns associated with the combined effects of ice melt, groundwater pumping, and dam building over the last century.”

This study brings together, within a statistical framework, observations and reconstructions of sea level, vertical land motion data, and physical models of ongoing sea level changes due to the last ice age to determine the sources of the observed variability in 20th Century sea level trends, according to Hay.

“We set out to determine whether ongoing sea level changes due the last ice age are driving differences in rates of sea level change along the U.S. East Coast,” said Hay. “Previous studies have disagreed on the source of this variability, mostly because no previous study combined all the different data sources and models, and their respective uncertainties, in a statistically robust framework.”

The researchers examined data across the current and last centuries, including a combination of tide gauge observations, GPS data, sea level reconstructions from salt marsh data, and models of long-term sea-level changes due to previous ice age cycles. They then used statistical methods to include all sources of uncertainty and make connections between the different data sets and models. The statistical analysis allowed the team to determine which processes are dominating sea level change in different regions along the coast, Hay said.

Given the results of earlier studies, Hay said the team did not expect to pinpoint the largest sea level changes due to the last ice age so far south along the coast.

“We were surprised that the largest rates of sea level change due to the last ice age are found in Maryland, Virginia, and North Carolina,” said Hay. “Numerous previous studies have suggested that the largest ice age effect is in New York, New Jersey, and Delaware. We were also surprised to find that the sea level rates not associated with vertical land motion still exhibit significant spatial trends. This had not been observed in previous work.”

Hay said it is important to note that while some of the sea level trends along the coast are influenced by climate change, this study targets sea level changes due to moving land, specifically those associated with the ongoing effects of the last ice age.

“While vertical land movement due to the last ice age is both the dominant driver of the spatial variability in sea level rates and a significant contributor to local sea level change, present day ice melt and heating of the oceans also play a large role in explaining the observations,” Hay said.

The next steps in this line of research will be to include additional sea level factors in the statistical model so that researchers can further explore the sources of spatial variability along the coast, according to Hay.


The Paper Here


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Ian Magness
December 26, 2018 2:17 am

I can’t read the whole paper, only the abstract. For those that can – rather than bland platitudes about land level rises from retreating glaciers, land subsidence (from various causes) and vaguely-disguised assertions that global warming also plays a part, do the authors try to break out exactly what they believe the various positive and negative contributions to changes in sea level actually are and in which areas? It all seems very woolly.

Reply to  Ian Magness
December 26, 2018 10:21 am

… present day ice melt and heating of the oceans also play a large role in explaining the observations,” Hay said.

Wow , sounds like they may be actually trying to be objective rather than making politically motivated “activist” points for the media.

Reply to  Greg
December 26, 2018 10:56 am

Does it really show they are trying to be objective? Rather, it shows they wrote their abstract and conclusion when they applied for their research grant. We are told, continuously, to “Follow the money” if a conservative funds a scientist.

If “the latest’ Global Average Air Temperatures are less than 1/2 of 1 degree above the baseline of 1975, and no measured ocean temperatures are measured increasing by the ocean buoys (recent ocean temperature “adjustments” are not measurements of a change, by the way) then please calculate the change in ocean depth caused by the measured ocean temperature changes.

True, a change in air temperature of the atmosphere may change the temperature of the ocean below, but at a 1/1000 factor due to the greater mass (density) of the water, and the greater heat capacity per gram of water compared to gram of air. IF the entire ocean were to absorb all the heat energy in that air. But it hasn’t.

So please, show us how a very small temperature change in the past 40 years of air has heated that column of ocean water to causing a steady, century-long 2.1 mm/year measured increase in sea level. And remember, if small air temperature increases between 1975 and 2015 affected sea level rise between 1920 and 2018, then WHY did the measured air temperature cooling between 1945 and 1975 NOT affect sea level rise between 1945 and 1975?

Dr. S. Jeevananda Reddy
Reply to  RACookPE1978
December 26, 2018 3:45 pm

Excellent question [last para]. Also adjusted data series of global temperature anomaly showed an increase. Individual country level they are showing cyclic pattern. Even global anomaly showed 60-year cycle from 1880 to 2010. This type of fluctuation is not seen in sea level rise!!!


Ron Long
December 26, 2018 2:42 am

Good catch on this report, CTM. Us geologists are familiar with these effects, and add variable sedimentation rates, sea-floor volcanism (this is a threefer deal: material added to sea floor, thermal expansion of sea floor, and thermal expansion of seawater), and tectonism of both sub-aerial and sea floor plates.
Ian, what does “woolly” mean? My mind is running wild with this one!

Ian Magness
Reply to  Ron Long
December 26, 2018 3:09 am

It appears “woolly” might not be a term used in the US (or wherever you are)! I shall quote the Collins English Dictionary and Thesaurus: “blurred, confused, fuzzy, hazy, ill-defined, muddled, nebulous, unclear, vague”. You get the idea!
As an aside (and I am a “lapsed geo” but still retain an interest), I have been compiling a list of factors that contribute to relative (you choose the definition) sea level change and that list just gets longer and longer by the month. The present disaster in Indonesia is illustrative of the many short- and long-term sea level side-effects of marine volcanic activity – and there may be much more to come as the volcanism develops. Try to extract useful data from tide gauges in that reason for this period – not easy. OK so those particular effects may be localised but then all global climate and related data start life in local form before it is extended, reconstructed, averaged, anomalised and generally messed about with before being presented as global graphs and tables that we are supposed to have trust in.

Ron Long
Reply to  Ian Magness
December 26, 2018 3:17 am

Ian, thank you for the definition of “woolly”, I can now restore my mind to a condition more appropriate to the day after Christmas. When your list of sea-level influences is essentially complete perhaps you could post it? Have a great day.

Reply to  Ian Magness
December 26, 2018 5:24 am

wholly cow a ‘technobabble’ term for fuzzy data

Reply to  ronk
December 26, 2018 6:04 am

Wouldn’t that, technically, be ‘wooly cow’?

Reply to  ronk
December 26, 2018 6:40 am

Better than a partial cow. Unless it’s being prepared for a barbecue.

Reply to  MarkW
December 26, 2018 10:15 am

Should be Holy cow if the BBQ is for Christmas

Ben Vorlich
Reply to  ronk
December 26, 2018 9:02 am

I believe that there are references go “woolly headed thinking” in the 17th century and so it probably predates fuzzy logic

Reply to  Ian Magness
December 26, 2018 10:18 am

Here is a good example of sea level rise due to siesmic activity in New Zealand.

Reply to  Ozonebust
December 26, 2018 11:01 am
Reply to  Ron Long
December 26, 2018 6:04 pm


You never hear or read the term, “pulled the wool over their eyes”?

Or ever saw a picture, or the real thing, of a sheep shorn of their wool? Where a chubby sheep is suddenly skinny?

December 26, 2018 2:47 am

Nice to see comments from Hay, and that he can take this down to a real level.

Reply to  nobodysknowledge
December 26, 2018 6:41 am

But can he take it down to sea level?

December 26, 2018 3:45 am

The Great Lakes’ water levels are slowly changing from isostatic rebound from the last Ice Age:

Patrick MJD
December 26, 2018 4:28 am

Do these people not realize the crust of the earth is about 50kms thick. It floats on thousands of kilometers of gooey molten rock which is constantly moving?

Dr K.A. Rodgers
Reply to  Patrick MJD
December 26, 2018 7:07 am

And then there’s rheid.

Louis J Hooffstetter
Reply to  Patrick MJD
December 26, 2018 7:36 pm

You got it. But people do better with analogies.
Help a brother out:
Skin on the pudding?
Skin on the Apple?
Frosting on the cake?
Scum on the pond?

Chris Thixton
December 26, 2018 5:08 am

Not sure where and how to post this. Merry Christmas Anthony and all the best to your family. You are a hero to so many of us and I guess that could be lost in the humdrum of the day to day conflict of this debate. All the best and hope that those recently affected by the fires in your region can come back stronger than before.

December 26, 2018 5:15 am

It’s isostasy at work. I learned about it (the term and what it means) in my 8th-grade science class, in 1968.

There are some “scientists” who need to go back to school and get real-world educations, rather than studying models.

Reply to  Nik
December 26, 2018 5:25 am

Science is an elective course now so most skip it.

Ron Long
Reply to  Don
December 26, 2018 5:32 am

I think you are partially correct, Don. They skip Science and take Social Science instead. Feelings, after all, are important and apparently a great substitution for thinking.

Reply to  Nik
December 26, 2018 5:56 am

Exactly Nik.
This is textbook physical geography and geology common knowledge from many decades hence.
In fact it has been mentioned in every single discussion on WUWT involving the reasons for sea level trend variations for as long as I have been reading here.
Anyone who has not known this for a long time is no expert.

December 26, 2018 5:24 am

The snarky commentary here (“duhh ” – is that a scientific term? SMH), from both Charles the Moderator in his subhead, and in some of the comments, is undeserved. The researchers described here are doing important and valuable research on the sources of variability in rates of sea level rise across the east coast, and they’ve preliminarily found some different conclusions than those reached in earlier studies.

They are not attempting to comment or, or research, the effects of global warming on sea level rise. So stop it with the snark.

Gee, one might think that WUWT simply disses all scientific research that doesn’t directly refute the theory of CAGW, and are engaging more in “political science” (i.e., propaganda) than real science.

Give it a rest dudes. The amount of knowledge and understanding of how our earthian systems work that we don’t have yet is infinitely greater than what we do have. In other words, the science isn’t settled.

Ron Long
Reply to  Duane
December 26, 2018 5:35 am

Calm down, Duane, nobody is denying the science of the study just adding to it. Science often advances by data from partial, but correct, individual studies, and their work adds to the knowledge. Have a great day.

Reply to  Ron Long
December 26, 2018 10:18 am

“Calm down”… LOL! The elevated snarky temperature of this post and thread is precisely that which I’m calling out. Calm yourselves down.

Pot calling the kettle black alert!

There is massive room in scientific discussions of climate change – which, by the way, is changing, and always has changed, and always will change – as well as related phenomena like sea level rise, that is actual science and not political diatribe and us vs. them tribalism. The particular subject post is one of that vast majority of studies that are actual science, and not “political science”.

Reply to  Duane
December 26, 2018 5:26 pm

The definition of science is not “those things that Duane agrees with”.

Reply to  Duane
December 26, 2018 6:00 am

Golly, what a surprise…a humorless warmista apologist in a snit over how other people talk and what they say.

Reply to  Menicholas
December 26, 2018 10:14 am

Golly, what a surprise, a personal attack made on a commenter who challenges the prevailing political snark as unfitting of a scientific discussion website, and who, uhhh, by the way, is fully in the CAGW skeptic ranks.

But go ahead, make everything political and us vs. them, and including us vs. us, if it suits your personal sense of paranoia and persecution complex.


Reply to  Duane
December 26, 2018 5:28 pm

Considering how frequently you throw insults, your complaining about insults falls flat.

Reply to  MarkW
December 27, 2018 5:53 am

Note I did not say you are a warmista, but you sure seem to spend a lot of time telling people how we should all feel about them.

Javert Chip
Reply to  Duane
December 26, 2018 9:45 pm


With the hope of receiving one of your intensely interesting & witty ad hominems (go ahead, give it a shot), I would point out, before you scolded the group, you threw the first fist-full of name-calling (though you do get extra credit for “prevailing political snark”, “us vs. us”, and my personal favorite “political diatribe and us vs. them tribalism). Man, you covered the waterfront.

The original question (still unanswered) was do the authors isolate & disclose the various contributions to sea-level rise, which would be an incredibly interesting piece of work. Now, if you are one of the authors’ mother, and here in disguise as a poster, well, you go right ahead and feel upset. Bless your heart.

Now that you’ve attempted (and magnificently failed) to control everybody’s speech, just back away from the egg-nog.

Reply to  Duane
December 27, 2018 5:56 am

BTW, that was a reply to Duane, not Mark, as I probably do not need to say.
As for my “paranoia”:
“Paranoia is an instinct or thought process believed to be heavily influenced by anxiety or fear, often to the point of delusion and irrationality.”

If I seem irrationally fearful to you, that may be a valid observation. Or it may be, itself, completely delusional.

Javert Chip
Reply to  Menicholas
December 27, 2018 6:39 am

No, it was aimed at Troll Duane; this new way of posting still causes mis-fires on where comments fall in the stack.

Mea culpa.

Reply to  Duane
December 26, 2018 6:43 am

The rest of the scientific community has been aware of isostatic rebound for over 100 years.
It’s nice that Duane and the rest of the trolls are finally recognizing it.

Reply to  MarkW
December 26, 2018 10:29 am

You are an idiot, sorry, there is no other word for your response. Calling out as a troll someone for calling out undeserved political science and snark masquerading as science discussion is idiotic.

You guys apparently sit around and snark all day long, laughing that these scientists (and me)are just now figuring out that elastic rebound of the earth’s crust as a result of glacial ice sheet retreat. That is a laugher.

I was taught that scientific fact (elastic rebound after glacial retreat) back in elementary school in the 1960s. And the authors of the subject study are not “discovering” that fact that you are so proud of discovering, like being able to poop in the toilet for the first time instead of in your pants, but rather, they are working on ascribing specific contributions of apparent sea level rise that do not necessarily agree with the prevailing thought and data.

If you actually bothered reading the post itself instead of snarking and brainless name-calling, the study authors found that apparent sea level rise varies by factors in addition to simple elastic glacial ice sheet retreat. Otherwise, the mid-Atlantic states, to which the ice sheets once extended, would have demonstrated lower apparent sea level rise than the South Atlantic states where the glacial ice sheets never made it.

Reply to  Duane
December 26, 2018 5:31 pm

Like most warmunists, Duane like to pretend that history starts with today.

As I said earlier, you like to define a scientist as anyone who produces a study that you agree with.

The fact that the phenomena that these “scientists” are talking about has been recognized by real scientists for over 100 years is why they are getting ridiculed.

The fact that you can’t tolerate the nonsense that you believe in being ridiculed is why you are being ridiculed in turn.

PS: I never said that I disagreed with their results, that’s your reading failure (amongst many), my point was, once again, that this is nothing new.

Reply to  MarkW
December 26, 2018 6:12 pm

Also notice Duane’s use of a true personal ad hominem. Not a twisted version of a rather innocuous statement.

Diane also worships this research’s conclusions, which never bother to explain isostasy rebounding far from where glaciers occurred.

Isn’t science amazing where dunderheads apply explanations without understanding?

Patrick MJD nailed the problem when he described Earth’s structure.

Javert Chip
Reply to  Duane
December 26, 2018 9:58 pm

Oh, man. We gotta find a way to get Duane bronzed. Talk about the gift that keeps on giving.

I’m now absolutely convinced Duane is the mother of one of the study authors, and is here doing her best to defend her offspring (“You are an idiot”, “You guys apparently sit around and snark all day”, and yet another personal favorite “like being able to poop in the toilet for the first time instead of in your pants”).

Duane is the perfect example of being able to write, but not to communicate, regardless of the quality of the idea. Duane’s strategy is to serve us sh!t sandwiches until we decide we like them.

Reply to  Duane
December 26, 2018 9:18 am

Cool it Duane. This isn’t cutting-edge science. At best it is “dotting the i’s” science, at worst “me too” science.

I can’t say which for sure since the press release as usual is written by somebody who has not slightest idea what he is writing about, and isn’t even smart enough to include a link to the actual paper.

Reply to  tty
December 26, 2018 9:44 am
Al miller
Reply to  Duane
December 26, 2018 9:22 am

Duane: were it not for the unceasing lies, exaggerarations, failed prophesies, rampant hypocrisy and let’s see, threats to jail non- believers etc., etc. I would be delighted to agree with you and engage in a pleasant disagreement, but the reality is not so, and we skeptics are sickened by the unceasing lies and hate being peddled by the true believers.

Reply to  Duane
December 26, 2018 10:30 am

You raise a valid point. After all a fair proportion of the commenters here repeat themselves and no-one goes DUH.
Does the DUH serve the skeptic cause, in my opinion no.

Clyde Spencer
Reply to  Ozonebust
December 26, 2018 12:14 pm

Tim Ball recently made a plea to cut out the personal attacks. ( ) How quickly some forget! I think that we should try to stick to the high road. Call out error of fact, dispute unsupported conclusions, even point out that a study isn’t providing anything new. But, try to keep it focused on the research, and not the the individuals.

To quote that great sage, Joe Friday: “Just the facts, mam.”

John in Oz
Reply to  Clyde Spencer
December 26, 2018 1:21 pm

Perhaps there would be less snark if scientists such as these in the current discussion were more vocal and public in calling out the wild and inaccurate claims of the CAGW-obsessed.

Most of the ‘science’ quoted when we are told of the dangers of sea level rise states that this is due to man-made global warming with isostatic rebound never mentioned.

Will this paper make it into the next IPCC boondoggle?

Clyde Spencer
Reply to  John in Oz
December 28, 2018 11:48 am

Actually, I do spend a lot of time calling out the “obsessed” in Yahoo comments. For my moderate behavior, I’m rewarded by being called, “liar, denier, idiot,” and the like. Hopefully, the fence sitters can see the “obsessed” for what they are. If I were to stoop to their level, there would be no distinction between us.

December 26, 2018 5:26 am

““While vertical land movement due to the last ice age is both the dominant driver of the spatial variability in sea level rates and a significant contributor to local sea level change, present day ice melt and heating of the oceans also play a large role in explaining the observations,” Hay said.”

True, but the article implies to an uninformed reader that all the “ice melt and heating of the oceans” is due to human-caused climate change, whereas actually most of that same rate of ice melt has been going on for centuries since the last ice age and the difference in sea level rise between that background and whatever is man-caused is very small.

Alan Tomalty
Reply to  TDBraun
December 26, 2018 9:44 am

Agree totally

December 26, 2018 5:29 am

Once again, we have a press release written by someone with a tenuous grasp of the subject at best.

The remaining sea level trends that cannot be explained by vertical land motion … This spatial structure is consistent with patterns associated with the combined effects of ice melt, groundwater pumping, and dam building over the last century.

Groundwater pumping and dam building cause vertical land motion. The writer claims to be quoting Hay but I bet she/he/it got it wrong. I also bet that she/he/it was bending over backward to avoid saying post-glacial rebound.

December 26, 2018 6:20 am

…well of course

This tide gauge is Ocean City, Maryland….out on a sandbar…and shows 2 inches a decade

..and this one is inland, Annapolis, Maryland….and shows a little over 1 inch a decade

…and this is Key West….a rock that’s not moving at all….and less than 1 inch a decade

Tom Abbott
December 26, 2018 6:29 am

From the article: “Hay said it is important to note that while some of the sea level trends along the coast are influenced by climate change,”

Yes, it is important. It is important to current peer revue, future grants, and future peer praise. In other words, it is obligatory if you want to remain in The Club.

December 26, 2018 7:02 am

Such “statistically robust framework” would be handy in challenging other measurement systems that are being used for advocacy.

Reply to  ResourceGuy
December 26, 2018 10:22 am

I will accept “statistically robust framework” when someone with Steve McIntyre’s or Ross McKittrick’ss math chops gives it the M&M Seal of Approval and no, I do not mean seal as in pinniped. 😎

December 26, 2018 7:10 am

As water is self levelling,& the seas are interconnected,apart from localised effectsof winddriven ,tides, (influenced by moon & sun),eathquake,volcanic activity & force of gravity ,rotational forces & possibly others .Where does all this apparently ‘ extra’ water ,1.5 ft ? in Chesapeake bay come from ? .
Is this an over simplification: the surface area of the oceans is about 510million squ.kilometres ,the volume of water required for thislevel of rise would be 510 million x .ooo45= 229.5millon cubic kilometres.the earths land ice is reckoned to be about 9,237000 cubic km.

Reply to  kendo2016
December 26, 2018 8:33 am

kendo2016 ==>The seas and oceans are not a bathtub. They are not self-leveling in any real sense — the ocean system is dynamic and causes and effects are complicated and complex (and, some aspects are dynamically chaotic coupled to the atmosphere). The result is a lumpy ocean.

December 26, 2018 7:15 am

The statistical work they did is beyond me, but almost all of their conclusions are consistent with my understanding of the patterns of sea-level rise along the east coast of the United States.

Their abstract concludes by saying, “Our results indicate that the majority of large-scale spatial variation in longterm rates of relative sea-level rise on the US East Coast is due to geological processes that will persist at similar rates for centuries.” That statement is certainly correct. In other words, those trends are best projected by simple linear extrapolation. There’s no reason to expect them to accelerate.

However, I was surprised that the authors did not mention two things:

#1. The Norfolk area (southern Chesapeake), where sea-level rise is most rapid, has a very unusual geological history:
I doubt that the unusual geology there, near the bolide impact site, is unrelated to its unusually high rate of sea-level rise.

#2. It is well known that, along the North Carolina coast the rate of vertical land motion (subsidence) decreases as you move inland. It sounds as though the authors might be unaware of that. I don’t know of any good explanation for it, but I doubt it can be explained by a sinking Laurentide ice sheet forebulge.

Reply to  Dave Burton
December 26, 2018 8:40 am

Dave ==> Yes, odd that the study does not catch the Chesapeake bolide impact that causes subsidence all through the region.

Also odd that no determination is done to account for simple land-fill subsidence at many tide gauge sites.

None-the-less, they do arrive at a proper conclusion: long-term change in Sea Surface Height (absolute Sea Level Rise) at about 1.7 mm/year. (their Fig 2, panel i) — which agrees with the generally accepted global value of 1.5-1.8mm/year.

E J Zuiderwijk
Reply to  Kip Hansen
December 26, 2018 8:51 am

Indeed. In the North Sea, on the other side of the pond from you, the rise has been a constant 1.9 mm/yr for at least the last 140 years, 0.3 mm/yr of which is attributable to geosyncline subsidence caused by thousands of years Alpine sediments deposited in the area by the river Rhine.

Reply to  Dave Burton
December 26, 2018 9:34 am
Reply to  Dave Burton
December 26, 2018 10:15 am

Pleistocene relative sea levels in the Chesapeake Bay region and their implications for the next century.

Jon Scott
December 26, 2018 7:59 am

Interesting that you need to be a paid researcher in 2018 to “discover” isostasy and its variations together with tectonics something I was taught as a geology undergraduate in 1979. I also was not able to read the full article. Was did bad town planning and groundwater extraction get a mention also as a cause? I ask because the climate alarm propaganda department of the BeeeBeeeeCeee either are ignorant of them or willfully ignore them when reporting on Miami or the Mekong Delta or……..”Better to have a runny nose than a runny brain” Blackadder 3rd

Reply to  Jon Scott
December 26, 2018 9:54 am

” did bad town planning and groundwater extraction get a mention also as a cause?”

Yes, but their conclusion was that the effect was minor, which is probably correct if you consider the East Coast as a whole.

December 26, 2018 9:12 am

“New analytical methods to pinpoint the reason behind the different rates of sea level change”

This is hilarious. Do modern “climate scientists” never read anything?

This was first described by Gerhard de Geer back in 1892: On Pleistocene changes of level in eastern North
America, Proc. Soc. Nat. Hist. Boston, Vol 25 pp. 454-477.

And the entire theory of eustasy and isostasy was essentially already formulated by Daly back in the 1930’s.

colin smith
Reply to  tty
December 26, 2018 10:34 am

For many “if it didn’t happen in their lifetime” it’s not relevant.
And if it doesn’t support the point being made it’s ignored.
And anyway humans are responsible.

I also like the reference point for the planetary temperature being “pre-industrial times”.
Which gives a lot of choice 🙂

December 26, 2018 4:27 pm

Your comments about learning about isostasy in the early 1960s could be back-dating your knowledge.
A friend graduated from the U of Saskatchewan in 1962 in Geological Engineering.
In that year Geophysicist Tuzo Wilson address the campus on plate tectonics which many were condemning. It was a large auditorium and the Geology Department did not like the concept of continental drift.
The entire faculty was sitting in a block at the back. In not asking any questions, they all stood up, en mass, and silently walked out.
I suppose an academic snub.

Reply to  Bob Hoye
December 27, 2018 8:57 am

Isostasy has little to do with plate tectonics. Isostasy really started out with the English geodetic survey of India back in the 19th century which discovered the gravitational effect of the Himalayas. The term was coined in 1889. George Airy (1801-1892) and Vening Meinesz (1887-1966) are perhaps the biggest names in isostasy research.

The effects of glacial eustasy has been known since time immemorial by people around the Baltic and caused a major academic/theological row in Sweden back in the eighteenth century (“Vattuminskningsstriden”). The theologians didn’t like the idea that sea-level wasn’t constant.

So, no Duane isn’t backdating anything. I learned about isostasy and eustasy about the same time.

Cyril Gibb
December 26, 2018 8:25 pm

I think it’s not “after the last age”. It’s after the last period of glaciation. We’re in an ice age.

Geoff Sherrington
December 26, 2018 11:39 pm

To assist with perspectives on sea level change, here is a photo of the volcano Sakurajima at Kagoshima, Japan.
Assume this to be a cone above water, 1,000 m high and with a ardius of 5,000 m. If a mass this size was to drop into the sea and sink, how much would global sea level change?
7.2 mm
72 mm
720 mm
7.2 m

Geoff Sherrington
December 26, 2018 11:42 pm
and the answer is 72 mm. This volcano is but a tiny pimple on the global surface, one of many coming and going as we write. How do you find accuracy measuring a basin whose shape is in constant change?

December 27, 2018 6:28 am

I live right on the Balcones Fault, 1,000 feet above sea level, on property that is mostly limestone, made from shell fish when the land was below sea level. This can make one a firm believer in changes in land elevation. We’re below the 30th parallel, and there is no evidence of any glacial activity here, either.
The earth is a blob of liquid rock, round because of gravity. We live on the thin surface shell, and our 1,000 ft. elevation is but a tiny fraction of the diameter. Thousands of square miles of miles thick ice a few degrees latitude away, could easily change our elevation, too. Whether and when it goes up, or down, is not certain to me.

December 27, 2018 9:09 am

You are probably too far away from the Laurentide and Cordilleran icecaps for them to have any significant effect.

The weight of sediments constantly being carried down by Mississippi/Missouri is certainly much more significant.

And the weight of the water in Lake Bonneville and the other pluvial lakes in the Rockies might possibly also be noticeable.

Your nearest pleistocene glacial activity is probably in the Sangre De Cristo and Sierra Blanca mountains in NM. Guadalupe mountains aren’t high enough.

chris moffatt
December 27, 2018 3:55 pm

I am always intrigued, nay amused, that while scientists may finally realise the impact of isostatic rebound and, possibly a first in these studies, the effect of grossly excessive groundwater extraction here in Virginia they remain seemingly oblivious to two other major effects that also affect local water level. These are that the lower Chesapeake bay is the site of a large impact crater, an asteroid I believe, that is still today collapsing into itself. The second is the unfortunate fact that much of the built-up areas of Tidewater Virginia are built on landfilled swamp that has been subsiding for up to three centuries due to compaction. This problem is common to many urban areas of the eastern US, particularly Boston. Nothing identified in this study is news but I suppose one should be thankful that the study team even identified non-AGW effects at all. I would be eager to see any other effects identified; one thinks that there must obviously be geologic processes along the eastern coast that have so far been unconnected to rising water levels.

Gordon Dressler
December 28, 2018 7:58 am

The study referenced in the above article is perhaps most interesting for the logical conclusion that it did not make: consider the mentioned effects, and some other key ones, when applied to full oceanic coverage of Earth.

To the best of my knowledge, there is no areal mapping of the regions of sea floor uplift and subsidence for the world’s oceans to an accuracy of better than a one meter per year (if that). Submarines may have accumulated data that would allow such mapping, referenced to GPS positioning, but if so I don’t believe such data has been publicly released due to its sensitive military value.

In the limit case condition of constant ocean volume, this fact alone precludes determination of true SLR to centimeters—let alone millimeters—of resolution. There is simply no reason to believe Earth’s crust/mantle “isostasy” requires that uplift and subsidence be in perfect global balance over timespans of hundreds to thousands of years.

Now, add in effects such as sea floor building due to underwater volcanoes, deposition of erosion coming from above-surface land masses, coral building and calcium carbonate detritus from marine life, and sea floor spreading between tectonic plates . . . and subtract out sea floor subduction between tectonic plates and sea floor compaction due to formation of limestone from organic, chemical or detrital sediments . . . and consider requirements for adjusting “global average” ocean volume for temperature, salinity, pressure (as a function of both overlaying atmosphere and subsurface depth) and above-surface water runoff (as a function of global precipitation and changes in atmospheric humidity and land temperature) . . . and . . .

Well, you get the picture: with all of these inaccurately determined variables, there is simply no way that proper scientific method is able to establish true global SLR to resolutions of mm/year that are being asserted by many institutions that should know better.

Gordon Dressler
December 28, 2018 8:33 am

Interesting juxtaposition of two segments taken from the above article:

1) “The team found that vertical land motion is the primary factor influencing the spatial variability in relative sea level rates, explaining 75 percent of the observed variation along the East Coast.”

2) ” ‘While vertical land movement due to the last ice age is both the dominant driver of the spatial variability in sea level rates and a significant contributor to local sea level change, present day ice melt and heating of the oceans also play a large role in explaining the observations,’ Hay said.”

So, the second quoted paragraph claims “present day ice melt and heating of the oceans” (i.e., global warming) plays “a large role” in explaining RELATIVE sea level rise data variability. Yeah, sure . . . a quantified-but-unstated 25% or less role! . . . with apparently little objective scientific data to support that assertion. One can only imagine such a claim—secondary to the main results of the study—was necessary to insure publication of the research results and/or to insure continued funding.

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