I live by the sea and like walking along the coastline including scrambling over the rock ledges in Noosa National Park. All the way from Noosa to Sydney it is possible to find wave-cut platforms etched out of the sandstone towards the bottom of the cliff faces.
The sandstone is very old, thought to date from the time of the dinosaurs, perhaps 180 million years ago, but the ledges – referred to as platforms when they are wide – are much younger. Expert geologists suggest that my favourite very wide, wave-cut platform, at the bottom of the cliff face that drops down from Boiling Pot Lookout, is about 125,000 years old.
It formed when sea levels were higher, and the cutting action of waves would have brought down great lumps of rock from above. The debris would have been removed by the wash, beyond the intertidal zone. The cliff face would have been receding landward as the sea ate into it. This is how cliffs are formed, and when they are of sandstone they sometimes leave behind ledges and wave-cut platforms as relics, showing sea levels were higher in a bygone age.
For the last few years, I’ve been standing on the wide platform at the bottom of the cliff face, below the lookout, at the time of the highest tide each year. Usually, the waves smash the rocks about a metre below, never reaching me. So, I confidently snub my nose at claims of unprecedented high sea level as repeated on the nightly news and in IPCC reports. I also use it as an occasion to agree with some geologists who argue sea levels were even higher 125,000 years ago, during that period known as the Eemian.
Except this past January the highest astronomical tide corresponded with a four metre swell from ex-cyclone Seth. It was the first year I didn’t stand on the platform at the moment of the highest astronomical tide. But my dear friend Jared did. I’ve made a short film about it all, entitled ‘Washed Away’.
Australia is a good place to study sea level change. Unlike Britain, Australia wasn’t covered in an ice sheet during the last ice age. Ice sheets complicate things because when all the ice melts – as Scotland’s ice sheet did a little over 9,000 years ago – part of the landmass may gradually rebound dragging its bottom half under. So, the north of the British Isles is rising, while the south has been sinking up to 0.6mm per year for the last 1,000 years – about 60 centimetres in total since the time of William the Conqueror. The sinking of this landmass is sometimes confused with rising sea levels, and it is claimed that this is occurring due to rising carbon dioxide emissions since the Industrial Revolution.
Where I live, about halfway down the east coast of Australia, sea levels began to rise about 16,000 years ago with the melting of Antarctica. By 9,000 years ago, sea levels around the world had risen by 12,000 centimetres, or 120 metres, the equivalent of a 25-storey building! The extent of this rise dwarfs the 36-centimetre rise that occurred over the last 150 years and the subsidence in places like Lincolnshire which adds up to just a few centimetres over the same period, both of which are worrying the Intergovernmental Panel on Climate Change (IPCC).
Indeed, it is uncontroversial, at least in peer-reviewed journals, that global sea level rise at the end of the last ice age occurred at a rate 10 times faster than the modern rate of about 3mm per year – which is about how much Scotland is rising due to isostatic rebound.
After being buried under several kilometres of ice, much of Europe and North America is experiencing uplift. For example, the ice retreated from Sweden 9,900 to 10,300 years ago and large-scale uplift is still occurring to the extent that the tidal gauge in Stockholm shows sea levels have fallen by about 50 cm over the last 129 years — an average annual rate of fall of 3.9mm per year. The uplift at Juneau, in Alaska, is even more extreme: in just 80 years sea levels have fallen by 120cm at a steady rate of minus 15mm per year. This reality jars with the notion of catastrophic sea level rise, so the IPCC ‘detrends’ the measurements from these tidal gauges, until they show sea level rise.
These numbers don’t make easy reading and may seem extraordinary, but sea levels really did rise globally by 120 metres at the end of the last ice age. Yet this inconvenient fact tends to be excluded from political summaries on climate change that rely on remodelled data.
According to the latest IPCC report on climate change – Assessment Report 6, published just before the 26th Conference of Parties (COP26) in Glasgow late last year – global temperatures are the warmest they have been for at least the last 125,000 years. There is no mention that in between it got quite cold, and Scotland (where that meeting was held) was covered in a lot of ice.
Given the landmass of Australia has not sunk or risen much over this time period, if the IPCC report is correct the waves should cover my favourite 125,000-year-old platform each high tide and I should be washed away.
The highest tide for this year was forecast for Monday 3 January at 8.27am. A four-metre-high swell was also forecast because ex-tropical Seth was lingering just off-shore. That morning, I hesitated. I didn’t go down to the platform and risk being washed away.
Instead, I positioned myself up a ledge and filmed Jared walking around to the platform to be there for the moment of the highest tide.
There are ledges at three different heights in Noosa National Park – and along the coastline all the way to Sydney. This is evidence etched in stone that there have been times in the past when sea levels were even higher than they are now. Why? Because the climate has always changed.
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This is a variation of an article first published in the UK edition of The Spectator magazine on 22nd January 2022 entitled ‘Aussie Life’.
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
Those who have an expectation of things remaining static are irrational. How boring would life be if all of this was static, hey?
I recall doing a science project in primary school (late 1970s) on the subject of tectonic plates. I devoured the “National Geographic” mags back then. It all made sense. Things move due to temperature fluctuations. Earth erodes. Just like the concrete path my dad and I built back in the early 70s. He didn’t use reinforced mesh. Just the concrete mix. Over the decades it buckled and cracked. An air bubble formed under the driveway due to erosion underneath. I used to bounce stones on that section to discover how big the bubble was getting. The air bubble did not reach the edge whilst I lived there (2 decades). The path was ripped up and replaced.
So, the planet is exactly the same on a bigger scale.
I don’t worry about any of these things the IPCC crap on about. They are morons in my view. They bore me. I find their claims amusing. I’ll now go check out the video you shared. Cheers!
Thanks Jen.
Talking about sea level fall, the best tide gauge for the biggest ocean in the world [the Pacific] is that one at Fort Denison that uses Sydney Harbour as a stilling pond and it is currently showing the latest [Feb 2022] Mean Sea Level as 99 mm LOWER than the first MSL [May 1914] which is telling us exactly what the late, great Nils-Axel Morner kept telling us, that sea levels are really not rising.
This is supported by the fact that Pacific atolls are also increasing in size:
http://www.bom.gov.au/ntc/IDO70000/IDO70000_60370_SLD.shtml
The IPCC dare not use factual data which has not been adjusted, corrected, homogenised or actual raw measured data because their entire climate agenda would be seen as the scam that it is. The entire climate debate is a political construction which is designed to impoverish the ordinary people and enrich the liberal globalist elites.
Actual science tells us that climate which is always changing does so in cyclical phases in response to natural phenomena and sea level changes are no exception.
I have tried to expound isostasy and eustasy concepts to people without geoscientific backgrounds but most cannot grasp the scales, nor the geophysics, I think.
Consequently, to most people 30 million years ago does not seem all that much different to 120 thousand years ago, so dynamic changes must have contemporary causes – ie. human activities.
That one can see the paleo-dynamic sequences in cliff faces is of no impact to most. I have gently tried to show this to people but the best one can get is polite disbelief. Using well defined coal seams as marker beds along the eastern zone of Australia maps the overlying geology at least back to the Upper Permian with confidence, so relative coastal cliff line dynamics have a sound basis for time intervals.
Even the famous chalk cliffs along the south-east coast of England, where the cliff face erosion is so rapid that photographs of just 50 years ago demonstrating the erosion rate (archived in small buildings open to the public near the cliff lines, these buildings in themselves having been force moved inland several times to avoid being dropped), fail to impact the mechanism on most people.
That Billy the Kid (William The Conqueror, 1066) is mentioned is helpful. The coastal area he landed his warships on (very carefully recorded in many historical records) is now a few km inland, with the intervening land strips now marshes and such. Yet the isostasy concept still seems to elude most people.
By coincidence, English coastal isostatic rebound and coastal erosion over time are discussed on https://cliscep.com/2022/04/19/the-sands-of-time/#comment-120408
Along the Dover chalk cliff lines, I observed medieval stone fences that are broken off at the now cliff line, with remnant stone pieces still strewn along the shingle beach. Geology is absolutely enthralling for me – I’ve spent nearly 50 years immersed in it professionally.
Jennifer, I am interested in why you believe these rock platforms relate to a 125,000 year high stand, my own thoughts are that they are more likely associated with the 6,000 year high stand.
The cliffs all down the NSW coast would seem to be too unstable to have retained the erosional notch so clearly for 125,000 years.
It is not unusual for substantial cliff falls to occur, so they are actively retreating rapidly in geological terms.
I have no evidence for my supposition other than my observations so I would be very interested if you have any references and I am happy to be contradicted.
You talk about sea level fall & rise in your short movie, but you don’t mention the land rising or falling or is it stable, In BC, we have subduction tectonics, our shore is rising.
I am a supporter of Bjorn Lombard & Steven Koonin work
Graham
I have been posting about The Platform since I’ve had a drone, so since about June 2019. I’ve received emails from several geologists who tend to think it dates to the Eemian. Though many waver in their opinion. Could it be that the higher platform above the Boiling Pot dates to the Eemian, and the lower wider platform (my The Platform) to the Holocene High Stand?
Interestingly, I can’t get a respectable expert geologist to come and have a look.
Brad
There is land subsidence at Brisbane to the south and Bundaberg to the north, the two nearest Sonel.org GPS reference stations. Brisbane is -1.8mm per year and Bundaberg is -0.8mm per year. This makes it even more remarkable that both wave cut notches sit so far above the highest astronomical tides.
Thanks for your response Jennifer.
I have been following your discussions of the rock platforms with interest, as I too have been intrigued by them.
I grew up on the coast and as a geologist I have taken a passing interest over the years and assumed the platforms were related to a sea level about 2 metres higher than today. To satisfy my own curiosity I started trying to find information on the timing of the last high stand. I was surprised at the lack of information, although that seems to have improved over recent years.
There may never be a simple answer as the platforms may be a result of a number of high stands not just a single event. The geological record is full of such small sea level fluctuations. Maybe they formed in the Eemian and were refreshed in the Holocene.
I appreciate your efforts and observations and I guess I have been hoping there may have been someone out there with some specialised knowledge. The platforms are a very significant feature of our coastal cliffs, and I have no doubt that they represent a sea level a couple of metres higher than today.
I’m not surprised that you can’t find a geologist to give a definitive answer, that is the nature of geology, a fact that drives mining engineers nuts.
Of interest:
From H.H. Lamb’s Climate History and the Modern World, 2nd edition, page 115 in the paperback –
“Of course, the details are less certain than the overall trend, but there is considerable agreement that the most rapid phases were between about 8000 and 5000 BC, also that the rise of general water level was effectively over by about 2000 BC, when it may have stood a metre or two higher than today.”
“global temperatures are the warmest they have been for at least the last 125,000 years.”..according to the IPCC.
What happened to the earlier warm periods of the Holocene? I can remember Mann’s hockey stick of 1999 and the elimination of the medieval warm period. I didn’t realise that the Holocene optimum, the Minoan and Roman warming had gone the same way.
Thank you for this. It is very well done. Drones are a wonderful addition to the toolbox, about like the transition from sketches to film.
May I add to the following:
“. . . sea levels began to rise about 16,000 years ago with the melting of Antarctica.”
The melting included land ice from many regions and released water, sometimes rapidly, into the World Ocean via numerous rivers. In North America sources include the St. Lawerance, the Hudson at NYC, Mississippi, Mackenzie, the Nelson into Hudson Bay, and the Columbia.
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I live in the Columbia River drainage and, so, am most familiar with this region.
Readers with time may find this site of interest:
https://hugefloods.com/Scablands.html
Wikipedia has an entry under “Missoula Floods”; saying lakes ” lasted an average of 55 years and that the floods occurred several times over the 2,000-year period between 15,000 and 13,000 years ago.”
“Several” is a whooping understatement!
Brad Haugan mentioned one alternative hypothesis that vertical motion of the land has raised this platform. The other hypothesis that needs to be countered is that the erosion is caused not by daily “normal” wave and tidal activity, but occurs during storms surges and other big events.
Thanks Noel.
Over the last 120,000 years the land mass of Australia is generally thought to have been fairly stable but with some vertical rise in the far north and some subsidence further south, eg. Noosa. Modern measurements indicate there is land subsidence to the immediate south at Brisbane to the immediate north at Bundaberg. These are the two nearest Sonel.org GPS reference stations. Brisbane is -1.8mm per year and Bundaberg is -0.8mm per year. This makes it even more remarkable that both wave cut notches sit so far above the highest astronomical tides.
If the cutting action was from storm surges then I can’t image it would be so level. The technical geological literature describes these types of platforms as formed IN the intertidal zone with wave action creating the very long and level WAVE CUT notch.