Not Washed Away, On the Highest Tide

From Jennifer Marohasy’s Blog

January 5, 2022 By jennifer 

It has been an exciting start to the year where I live, because the highest astronomical tide was forecast for 3rd January and there was a cyclone tracking towards us.

On the highest tide each year, I wonder if the waves will reach to the wave cut notch at the bottom of the cliff face, below Boiling Pot Lookout in Noosa National Park that is about halfway down the east coast of Australia, just near where I live.

I have been going around and standing there on the lower platform (Platform 1) for some years at the time of the highest tide.   These tides are in summer in the Southern Hemisphere because that is when the Sun is closest to the Earth, and they usually correspond with a New Moon or Full Moon.

Jen and friends towards the top of Platform 1 waiting for the highest tide for the year in 2020. It didn’t reach as far as us, we weren’t washed away.

This year, on the day of the forecast highest astronomical tide (Monday 3rd January 2022), Noosa was mentioned on the front page of the national newspaper – the story was about the huge swells: up to 4 metres high from ex-cyclone Seth lingering just offshore.

Was this the year I was going to be washed from the wavecut platform at the bottom of the cliff face on the highest tide?

The sea begins at the land’s edge.  Where the sea begins is the sea level – and there is concern that sea levels are rising.

But this platform must be a relic from a time of higher sea levels because even this year with a low pressure system off-shore that raised sea levels, and with the La Nina that further raised sea levels, sea-level didn’t reach the wave cut notch.

These platforms form just below sea level, in the intertidal zone, where the cutting action of waves will bring down great lumps of rock from above.  The debris is removed by the wash, beyond the intertidal zone; the headland recedes landward; the sea eats into the cliff-face; and so, cliffs are formed, with wave-cut platforms at their base.

This platform below Boiling Point Lookout, that I have stood on in past years: it is so wide.

When was it formed? How long were sea levels at that height – how long does it take to erode a cliff face to that width?

This year the waves, on the biggest swells, at the time of the high tide, they hit the cliff face!

Not the sea level, but the swells.

And yet I wasn’t washed away.  Because I wasn’t on the platform!

But my friend Jared was there, and he was not washed away.  You can see him in the drone footage that I have taken – so much footage that now needs editing – that shows the largest swells including as they hit the cliff face the day before (2nd January) with Cyclone Seth just offshore, and the next day (3rd January) which was highest tide day for the year.

Can you see him, my friend, Jared? In a white tee shirt, waiting for the highest tide below Boiling Pot Lookout with the big swells from ex-tropical cyclone Seth.   You can see him and the waves smashing in the footage that I hope to make into a little film.  To know when the short film is released consider subscribing for my monthly e-newsletters.

I was flying my drone (the wonderful Skido) from a ledge beyond the platform into the winds and out to sea so I could get the feature image looking back at the cliff face at the time of the highest astronomical tide, as shown in the feature image at the top of this blog post.

This year I dared not venture below the cliff face at the time of the highest tide, but Jared did – and he was not washed away.   You will see him in the short film that I hope to make about this cliff face and climate change.  To be sure to know when it is uploaded to the internet or ready for showing in the wonderful local Pomona Theatre subscribe for my monthly e-newsletters.

A photograph of Platform 1, taken by Bruce with his phone, just before the highest tide on 3rd January 2022. He also braved the conditions and saw it all with his own eyes.
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John Tillman
January 5, 2022 2:15 pm

Redating the earliest evidence of the mid-Holocene relative sea-level highstand in Australia and implications for global sea-level rise
But maybe the wave cut dates to the Eemian, with even higher MSL.

Reply to  John Tillman
January 5, 2022 2:26 pm

Harlech castle sea gate 1000 years ago. At least that far above present day sea level.

John Tillman
Reply to  Chaswarnertoo
January 5, 2022 2:39 pm

The situation there is complicated by isostatic rebound of northern Britain and consequent depression of southern.

Harlech might be close enough to the middle not to be much affected either way.

The Roman shore defense forts now far inland are all the more telling, given dipping of the Saxon Shore.

The Holocene highstand in Oz however was long before the Roman or Medieval Warm Periods. It came thousands of years earlier, during the Holocene Climate Optimum.

Oz is a good place to study MSL changes, since the continent didn’t have an ice sheet during the Pleistocene glaciations. Mountain glaciers did of course grow on New Guinea and even in the Snowy Mountains and Tasmanian Highlands, but not enough ice mass greatly to depress the continent of Sahul.

Mike Jonas(@egrey1)
Reply to  John Tillman
January 5, 2022 4:15 pm

I think you will find that the whole west coast of England/Scotland/Wales is rebounding. The (sea) boat ramp at Dunster Castle in Somerset (very SW England), for example, is now over 50m above sea level and a full mile from the coast.

London and the east coast may be sinking (I haven’t checked).

John Tillman
Reply to  Mike Jonas
January 5, 2022 4:24 pm

Which would make Harlech even more indicative of higher Medieval sea level.

Reply to  Mike Jonas
January 5, 2022 8:49 pm

UK Cinque Ports

john harmsworth
Reply to  Dennis
January 6, 2022 11:29 am

Yes! They should all move to the mainland to more greatly enable the isostatic rebound by getting their stupid weight off the coast of Britain. Please propose that at the next meeting. Save them all continuing to look like fools by buying into the “Global warming “farce. Also, please inquire if any of them know the air speed of an unladen swallow.

Tom Abbott
Reply to  John Tillman
January 6, 2022 9:04 am

“The situation there is complicated by isostatic rebound of northern Britain and consequent depression of southern.”

It’s always something! 🙂

Reply to  Tom Abbott
January 6, 2022 4:27 pm

Caused, no doubt, by the increase in anthropogenic CO2

Ron Long
Reply to  John Tillman
January 5, 2022 2:53 pm

Good report you cite, John. The mid-Holocene highstand of sea level, coupled with the 120 meter rise since end of last glacial cycle, shows the tremendous natural variance in climate cycles that geologist are used to observing. Every CAGW funding application should be made to explain current minor changes against these large, natural changes. Not going to happen.

John Tillman
Reply to  Ron Long
January 5, 2022 3:08 pm

Glad you like it.

In geologic time, 8000 years is but an Augenblick. If that.

You want to see sea level rise, look at the last glacial termination.

Ed Hanley
January 5, 2022 2:19 pm

This is a much more adventurous, and detailed, method of watching maximum sea levels than simply checking a tidal gauge. It certainly gives an important data point in the “rising sea levels” story that needs to be taken into account.

Reply to  Ed Hanley
January 5, 2022 2:45 pm

Jared missed out on receiving the Darwin Award for becoming extinct.

John Tillman
Reply to  gringojay
January 5, 2022 3:21 pm

It’s great to be young!

If not for long.

Jennifer Marohasy
January 5, 2022 2:56 pm

I’m very grateful to WUWT for republishing this note with my drone shots.

I would be very keen to know from geologists, with relevant expertise, how old they think platforms 1 and 2 are?

Platform 1 is well defined in terms of its width. How long would it take to erode sandstone to this width?

The cliff face is sandstone that probably dates back 180 million years. It likely formed in a sedimentary basin from the erosion of volcanoes when sea levels were lower and/or the landmass of Australia was sitting relatively higher. Is it the subsidence of the Australian landmass and/or rising sea levels that first created this coastline? When did this occur?

John Tillman
Reply to  Jennifer Marohasy
January 5, 2022 3:37 pm

The age of the rock can be dated, but estimating when chunks of the cliff face fell off is hard, but not impossible.

If the platforms were there in the oldest photos and memoirs, then scientists could look below the rocks for clues. Also at their state of water erosion.

The coastline of Oz changes with every glacial cycle. Most of the time for the past 2.6 million years, ie during glaciations, Oz proper, Tasmania and New Guinea are all connected by land above sea level. As shown by the many islands between the Cape York Peninsula and New Guinea, the Arafura Sea is a shallow, epicontinental sea, ie on continental shelf exposed during glaciations.

Torres Strait was inundated about 8000 years ago, ie around the time of the Holocene highstand.

John Tillman
Reply to  Jennifer Marohasy
January 5, 2022 4:45 pm

Jennifer, I’m sorry that there have been so far so few comments on your wonderful contribution. Real world expedition, even stunts, like this are examples which lay people can grasp, and draw conclusions therefrom.

Wsie of you to leave the platform occupation to Jared. Unfortunately photographic drones can’t yet conduct air-sea rescue operations.

Reply to  Jennifer Marohasy
January 5, 2022 9:53 pm

This was a brilliant and tangible demonstration, of which we certainly need more. The inaccessibility of visible reality to the average citizen is a real problem with the entire discussion.

Rud Istvan
January 5, 2022 3:02 pm

The Eemian highstand was about 120kya, and was about 2 meters higher than the Holocene highstand. That is when those shelves were likely cut. And unlike O’Leary’s scientific misconduct paper claiming Wais collapse, the maximum SLR then was about 2.2mm/year, equivalent to the present dGPS corrected long record tide gauges. Note, per Greenland ice cores, the Eemian highstand also corresponded with a Greenland temperature about 6-8C higher than present.

John Tillman
Reply to  Rud Istvan
January 5, 2022 3:24 pm

In the Eemian, the Southern Dome of the Greenland Ice Sheet melted about 25% more than now. The Northern Dome was much as now.

Jennifer Marohasy
Reply to  Rud Istvan
January 5, 2022 4:05 pm

Rud, Thank you so much for your comment. I initially started reading everything about Holocene High Stands to understand the platforms/shelves. And I concluded they were a lot older. Can you point me to relevant studies of similar cliff faces that conclude the shelves are that old, date to the Eemian High Stand? What you write makes sense, I would just like to be able to quote a research paper, as well a your advice.

Rud Istvan
Reply to  Jennifer Marohasy
January 6, 2022 6:47 am

For all the details see essay ‘By Land or by Sea’ in ebook Blowing Smoke. The best (IMO) Eemian highstand paper is Kopp et al Probabilistic Assessment of sea level during the last interglacial stage, Nature 462: 863-867 (2009).

Chris Hanley
Reply to  Rud Istvan
January 5, 2022 4:33 pm

… latest research … establishes the divergence of polar and brown bears at 400,000 years ago … (Wiki).

Your typical Polar Bear during the Eemian.

John Tillman
Reply to  Chris Hanley
January 5, 2022 4:40 pm

They could relax, needing fewer ringed seal pups as high-fat energy pills.

Life was good.

H. D. Hoese
January 5, 2022 3:30 pm

“It seems to me to be evident that the position of a shoreline at any time and place is determined by an exceedingly complicated equation….” Shaler, Evidences as to change of sea level, 1895. Shaler, N. S. 1895. Evidences as to change of sealevel. Bulletin Geological Society America. 6:141-166. I have stood on lots of shorelines, even a few in Australia, with from tiny to highest astronomical tides. Is this not still the best, simplest summary? I think that we need more tide gauges in many places, not an original idea.

Jennifer Marohasy
Reply to  H. D. Hoese
January 5, 2022 4:30 pm

Hi HD Hoese, Isn’t it fun, standing on a shoreline and watching the waves break. If you could send me the paper by Shaler, published back in 1895. My best email is JenniferMarohasy at

January 5, 2022 3:38 pm

Off topic;
In NZ East coast we have also coastal platforms which geologists call “wave cut” . However the soft mudstone of the area has swelling clays; Whenever the clay dries and shrinks it shatters about a 10mm layer of surface. Over a year the measured retreat of the coastal “cliff” is 150 to 200mm. Just below low-tide level the mudstone stays intact enough to form platforms up to 200 metres wide before the real wave-action breaks them away.
These Australian sandstones are different; but I am curious if there is a thin layer of rock in that cliff just above these platforms that has a swelling-clay content.
Would love to visit just to see and grab samples………Funding anyone ?

Jennifer Marohasy
Reply to  Walnutter
January 5, 2022 3:59 pm

Walnutter, I’m really interest in your comment and would be keen to get you to my cliff face. I can almost certainly arrange funding if you have something to add in terms of the age of the platforms and also the mudstone. If you send me an email, jennifermarohasy at is best. Then we can see when might suit you best, to come look.

Reply to  Jennifer Marohasy
January 5, 2022 10:34 pm

Hi Jennifer;
Alas, I should have added a /sarc note after the funding quip.
My expertise is limited to local observation of various forms of erosion and the results; bouncing ideas off “recognised experts”, and a basic degree in agriculture.
Anyone local can have a look at the cliff face and chip off bits of fine grained stone at the upper surface level of this marine bench; then take them home and dry in an oven (or the open sun for a week or two) and observe if they self-destruct.

Rock-age wise; I lean more to the young-earth creationist viewpoint as best fitting most of the stuff we can observe today.
Most conversations tend to end about there.
Cheers, nzwalnutter at the gmail

Reply to  Walnutter
January 6, 2022 11:46 am

“God created humans in their present form at one time within the last 10,000 years”

Cro-Magnon man joined the Neanderthals in Europe around 48,000 years ago, give or take. It appears that changes in climate due to a fading ice age favored the Cro-Magnon’s. With several distinct new genetic traits in the Cro-Magnons and very likely interbreeding with Neanderthals caused Neanderthals to gradually disappear.

The latest research seems to indicate that may have happened around 28-29,000 years ago. So, you can ascribe it to God directly or believe he used evolution to get His ends.

John Larson
Reply to  Philo
January 6, 2022 6:55 pm

Or, he can “lean more” toward the possibility that the current situation in “climate science”, is not the first time that “consensus science” became something of a socio-political juggernaut, which led to some intellectual rigidity, and possibly even some “fudging” of the data, etc, right?

(John’s logic rule 1: If it is happening, it can happen ; )

Reply to  Jennifer Marohasy
January 6, 2022 7:09 am

Jennifer and all –
Dan Muhs of US Geological Survey spent most of his career studying sea-level changes around the world. Lots of dating information from carbon-14 and uranium-series techniques.

Here’s an example

A prominent wave-cut terrace can be seen in numerous locations in the Pacific and Caribbean, 5-8 m above modern sea level, typically recording high-stand of the Eemian at 120,000 yBp

Jennifer Marohasy
Reply to  GeologyJim
January 6, 2022 8:00 pm

So much thanks for that link!

January 5, 2022 3:45 pm

Since the entirety of the Holocene Optimum was several degrees warmer than today, it stands to reason that the sea levels would have been higher as well.

The Medieval, Roman, Minoan and Egyptian warm periods were also warmer than today.

John Tillman
Reply to  MarkW
January 5, 2022 3:59 pm

Peak HCO and Egyptian WP were about equal. But, worrisomely, Minoan, Roman, Medieval and, to date, Modern WPs show declining peaks.

As a rough estimate, globally, I’d say that the HCO and Egyptian (~4 Ka) temps were about 2 degrees C higher than now (much more in the Arctic). Minoan (~3 Ka) was probably about 1.5, Roman (~2 Ka) 1.0 and Medieval (~1 Ka) 0.5 higher than now. If we’re lucky, the Modern, thanks to human activity, might break the downtrend and equal the Medieval.

But then it’s back to the inexorable decline into the next glacial phase. Although giant, fusion-powered blowdriers above 65 degrees N might forestall that calamity. Or coaldust spread upon the unmelted snow still left in September.

Reply to  John Tillman
January 5, 2022 11:51 pm

Do you have any info supporting those differences. They look too big for me. Most researchers place the difference between the LGM and Holocene in the 4-6ºC range.

To me differences between the HCO and the bottom of the LIA higher than 1.5ºC are difficult to support, and most likely the range is 1-1.5ºC. One has to take into account several important things:

  • Orbital changes resulted in much higher NH summer temperatures particularly at high latitudes. Over-representation of NH proxies gives an incorrect difference
  • Seasonality was a lot more marked, summers were much warmer in the NH, but winters were colder. This has to be taken into account when using proxies that respond to growth season.
  • A difference of 0.2ºC over 1000 years produces a bigger effect than a 0.6ºC over 70 years in a lot of proxies. The Roman Warm Period gives the impression of being warmer because it was very very long.

To me every millennium since 5000 BP has been c. 0.2ºC colder than the previous, and that includes the second millennium AD despite 18-20th century warming. I see no reason why the third millennium shouldn’t be 0.2ºC colder than the second. Milankovitch has a heavy hand.

Last edited 20 days ago by Javier
John Tillman
Reply to  Javier
January 6, 2022 7:48 am

While I believe its depth was colder, studies in this century have found the LGM about 6 degrees C colder than now.

Zurich U. animation, with estimated figures:

HCO temperature is hard to average out, as the difference with the present declines greatly with latitude. The tropics might have been only one degree warmer, but poles up to nine degrees, depending upon season.

Consensus now is around 1.5 degrees C on average, but that’s down from pre-CACA estimates. IMO 2.0 degrees is justifiable.

This figure shows Minoan WP average SST well over two degrees warmer than in the late 20th century::

comment image

Yes, each millennium since 5000 years ago has been on average cooler, and the trend hasn’t yet broken. We’re headed back to the next ice age, unless human intervention can keep snow from accumulating at 65 N.

Last edited 19 days ago by John Tillman
Reply to  John Tillman
January 6, 2022 8:22 am

There is a trend in studies to increase the LGM-HCO temperature difference over time, because otherwise the effect of CO2 in deglaciation must be negligible and doesn’t fit the proposed effect on Modern Global Warming.

I find that figure totally unconvincing. That is Rhodes Fairbridge reproduction of a figure on Sargasso Sea SST in a Keiwig paper in Science from 1996. Keiwig says that up to a third of the d18O changes in that figure could be due to salinity changes.

I fail to see how an uncertain figure from the Sargasso Sea would demonstrate anything about global temperatures of the past. In case you haven’t noticed that figure shows the MWP warmer there than most of the RWP contradicting what you said above. I’ve read lots of things from RW Fairbridge and I find him unreliable and prone to stretching arguments. In this case he shouldn’t have used that figure to support the MWP, or at the very least he should have mentioned the great uncertainty it carries since he was aware of it.

Bill Treuren
Reply to  Javier
January 6, 2022 10:57 am

The poles experienced far greater temperature variations than the sub tropics.
Here in NZ we had vast forests of Kauri trees 42,000years ago as documented by the Adam’s event tree and they are sensitive to a fall of probably less than a degree or two.
So in the depths of the iceage the North of NZ was temperate and the South was in a full glacial state just 1500Km away.

Reply to  John Tillman
January 6, 2022 4:17 am

Don’t panic, John. The decline to full Ice Age conditions will take far longer than you (or I) will live – like about 40,000 years.

John Tillman
Reply to  Disputin
January 6, 2022 7:54 am

Depends upon which Milankovitch cycle you think is most important, ie tilt, eccentricity or another. I’m in the tilt camp, which means thousands of years until the next NH ice sheet formation.

If eccentricity rule, then, yes, we could enjoy warmth for perhaps 30,000 more years. In such a super interglacial, the Greenland ice sheet can melt, as happened ~400,000 years ago, during MIS-11:

MIS-11 duration key to disappearance of the Greenland ice sheet

spangled drongo
Reply to  MarkW
January 5, 2022 4:43 pm

It is interesting that this Australian BoM web site that has been showing that Mean Sea Level in the Pacific for the last century plus is actually going nowhere, is now out of order.
When you can’t face facts, deface them:

John Tillman
Reply to  spangled drongo
January 5, 2022 4:50 pm

Readings in the Western Pacific are actually negative.

It’s all down to relative frequency of Los Niños and Las Niñas. That oscillation far outstrips whatever negligible effect more plant food in the air has.

Reply to  spangled drongo
January 5, 2022 4:54 pm

You missed the message that is real world data which doesn’t count it is what your model says that is important.

Last edited 20 days ago by LdB
John Tillman
Reply to  LdB
January 5, 2022 5:26 pm

Those messages aren’t just memos, but directives to be followed if you want grant funding in future.

It’s science!

January 5, 2022 6:11 pm

Thanks for your post.

January 5, 2022 7:48 pm

Jen, OK, most erosion surfaces are the result of storms, not sunny calm days.

Jennifer Marohasy
Reply to  WXcycles
January 5, 2022 11:05 pm

Oh XYcycles, we had two sunny mornings with huge swells, 3 to 5 metres. and fair winds, probably 30 knots. the wave-cut notch is so neat and consistent across platform 1 that I really can’t believe it is from the odd storm, but rather from a time when sea levels were that much higher and the platform was mostly covered in water, part of the intertidal zone

Bill Treuren
Reply to  Jennifer Marohasy
January 6, 2022 11:00 am

Formation change maybe, during deposition??

Reply to  Jennifer Marohasy
January 6, 2022 7:13 pm

Jen – I think WXcycles has made a valid point there. The notch will have been cut during storms. Over “geological time” scales – storms are not “odd”

January 5, 2022 8:47 pm

My property has been family owned since late 1800s and nearby there is a tidal saltwater lake, highest tide mark has not changed noticeably.

Australia, NSW Mid North Coast

Last edited 20 days ago by Dennis
Geoffrey Williams
January 5, 2022 11:02 pm

Sea level rise is just another of the alarmist memes that have brainwashed the public. Erosion along the coast is inescapable, it’s what oceans do when they meet the land be it rock or sandy beach. Unfortunately the public see this erosion and confuse it with sea level rise.
The alarmists should be ashamed of their lies.

January 6, 2022 10:37 am

Really interesting and great photos.

January 6, 2022 4:37 pm

Professor Peter Ridd, a colleague of Dr Jennifer Marohasy, was interviewed last night on Sky News Australia and during the discussion he was asked about the present day health of the Great Barrier Reef, Queensland.

He replied that the GBR is in excellent health, that from his research sediment and other material from land based activities does not reach the GBR in any significant quantities.

Another climate hoax deception exposed.

James Bull
January 7, 2022 8:56 am

You don’t understand it’s not about actual sea level it’s what the woke wonders feel about the sea level and in their little world it’s the worstest it’s ever been ever!

James Bull

Peter Nielsen
January 7, 2022 2:37 pm

“Form is created by extreme events”, meaning that the notch was NOT cut by the normal kind of event you experienced, but by say a 1,000-year event . . .

January 8, 2022 6:18 am

Sea level change can be impacted by changes in absolute water height, and changes in the land height.

The platform may not be a relic from a time of higher sea level, it must only be a relic of a time of relative higher sea levels to that rock.

Reply to  Dean
January 10, 2022 9:17 am

Good point Dean. We mapped glaciomarine deposits for an undergrad class and found sea level here in coastal NH was at present day 220 ft asl.

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