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As you read this today, the summer extent of the Antarctic sea ice sheet once again will have reached its long-term average for the beginning of February — an average based on what is now almost four decades of satellite observation ongoing since 1981. Given that we are bombarded by activist climateers, a unquestioningly gullible mainstream media and legions of doomsayers’ constant reminders of the dire straits in which the planet allegedly finds itself, it may surprise many to learn of this fact, especially in regard to what we are told are the looming and catastrophic rise in sea levels. There is, however, no need to fret.
It is an incontrovertible truth that seasonal sea ice melt at both poles has no appreciable effect on global mean sea level due to the fact that sea ice floats; when it changes state from ice to liquid its volume is equal to the water it displace, leading to no net change. If this weren’t the case we would experience significant sea level shifts on a seasonal basis. However, the complexities aroundAntarctic and Arctic sea ice sheets are in many instances not shared. For instance, the Antarctic ice sheet is a greater combination of large continental ice flows and annual sea ice formation than its Arctic counterpart. What can be extrapolated with some degree of certainty is that the greater the extent of sea ice, the colder prevailing conditions. Were this not true, those who object to such a correlation might seek to explain why sea ice extended to around 50 degrees north latitude at the height of the last major ice age, as indicated by the map below.
It is also the case that the greatest threat postulated by anthropogenic global warming (AGW) alarmists to sea level rise is a melting of the Greenland and Antarctic continental ice sheets. Yet NASA Earth Observatory reports the largest of the Greenland glacier, the Jakobshavn Glacier in western Greenland, has grown substantially in the last three years to June 2019, adding as much as 30 metres thickness per annum.
Back in early October of 2018 this journal highlighted the hyperbole surrounding the September 2019 IPCC ‘Special Report on the Ocean and Cryosphere in a Changing Climate’. Supporters and contributors to that document, such as Professor Mathew England, were quick to hit the media with dire proclamations of an imminent ‘tipping point’ that would see sea levels rising by metres in the not-too-distant future. So let us take a quick look at how things are going for the catastrophists on the polar ice-sheet front.
As stated above, the Antarctic sea ice sheet is now back to its mean extent for the middle of summer. Now while it’s true that it has come off a low base from the 2019 winter, where its extent was well below mean, it can’t be overlooked that the current relative abundance of sea ice has occurred in the context of nearly 420ppm atmospheric CO2 and a southern hemisphere summer that alarmists claim, yet again, to be the hottest-ever. And let’s also not forget it was only a few short years ago, in the winter of 2014, when Antarctic sea ice was at the greatest extent ever recorded — that was the year after Professor England’s UNSW colleague Chris Turney led the infamous “ship of fools” expedition to study the “vanishing” ice, only to find himself and fellow climateers hopelessly stuck in the stuff. It will come as no great surprise to any grounded observer that the extent of Antarctic sea ice oscillates through the full range of its bell curve over the course of time due to all the variables that determine extent at any given moment. What should be a surprise to anyone who has bought into AGW fearmongering is that, in the face of CO2 levels now at 1.5 times the supposed ‘Goldilocks level’ of 280ppm, the Antarctic ice sheet is proving highly resilient and, as of right now, is back at ‘situation normal’.
What about the Antarctic’s obverse? What is the current status of Arctic sea ice extent? Well, once again, as we approach the depth of the Northern Hemisphere winter, things also could be described as normal. Indeed, current Arctic sea ice makes a mockery of those who have argued that the all-year opening of the North West Passage to shipping is only a matter of years away — a belief also current in the 1840s, when the Admiralty responded to sealers’ accounts of a melting Arctic by sending a former Tasmanian governor, Sir John Franklin, two ships and some 150 seamen to chart the fabled Northwest Passage. Then as now, the Arctic failed to cooperate, and the entire expedition perished.
For interest’s sake and historical perspective, it is worth citing the case put to the Admiralty by the Royal Society — warmists then and warmists today — which sent Franklin and his party to their doom:
It will without doubt have come to your Lordship’s knowledge that a considerable change of climate, inexplicable at present to us, must have taken place in the Circumpolar Regions, by which the severity of the cold that has for centuries past enclosed the seas in the high northern latitudes in an impenetrable barrier of ice has been during the last two years, greatly abated…
…this affords ample proof that new sources of warmth have been opened and give us leave to hope that the Arctic Seas may at this time be more accessible than they have been for centuries past, and that discoveries may now be made in them not only interesting to the advancement of science but also to the future intercourse of mankind and the commerce of distant nations.
While today’s northern hemisphere’s sea ice extent is the tenth-lowest on record since 1981, it is also comfortably within its interdecile range. If you are interested in what that discrepancy looks like on the ground, take a good look at the latest image (above) from the National Snow & Ice Data Centre (NSIDC) at the University of Colorado, where the red line indicates the recorded mean between 1981 and 2010. The difference in sea ice extent as currently observed is analogous to the difference in a persons’ height from first thing in the morning to that at the close of the day — essentially inconsequential. And with peak sea ice extent usually experienced in early March it may well yet meet the mean extent or even exceed it.
And here is the thing with polar sea ice, it’s a bit like a T20 cricketer in the sense that they are only as good as their last game. While long-term trends clearly matter, the oscillations of the numerous climactic permutations that lead to both above-average and below-average sea ice likely play out over centuries rather than a mere handful of years. It does nothing to sustain the argument of permanent and irreversible AGW and sea level rise if the ice sheets flux to low levels but then grow again to normal levels and perhaps beyond. For the theory of irreversible sea level rise to hold any water at all, the continental ice sheet degradation also needs to be permanent and irreversible over a very extended timeframe. It is an anathema to the claim of permanent sea level rise if ice sheets were low for a handful of years but are now growing again. The here and now is all that matters. And the here and now for polar ice sheets looks encouraging.
How will the alarmists and catastrophists explain such an anomaly? By the IPCC’s reckoning and that of the doomsday cheer squad at the ABC we are already in a runaway global warming scenario. By such reckoning ice sheets should never again reach normal mean values, in the context of a sustained ‘global’ rise in mean temperature. It certainly doesn’t bode well for catastrophic sea level rise. With just 10-12 years before all is lost, depending on which climatic Chicken Little you prefer, the catastrophists have just had one of those years pulled out from under their feet, effectively setting back the doomsday climate clock to 1981 levels. The world, or so it would appear, has just bought itself another four decades.
For all the hot air emanating from the AGW circus all we have to show for it currently is an Antarctic sea ice sheet at long term average extent for summer, plus an Artic sea ice sheet that is within 10 per cent of the very same. Indeed, one can conclude that, overall, atmospheric temperatures and polar ocean currents at both poles have been colder in the last three months than during the same period over recent years. We may even be at the commencement of a cooling trend for the planet’s polar ice caps. If so, it will be fascinating to watch the alarmists switch stories. What will remain consistent — and you can take this to the bank — is that the cup-rattling for grants, subsidies and business-class seats to climate gab fests will continue. Climate changes, climateers never will.
In recent weeks even the uber catastrophists behind the 2017 Thwaites ‘Doomsday’ Glacier report that projected over a metre rise in sea level by 2100 due to melting Antarctic glaciers, displacing a guesstimated 150 million people, have revised their projections down by a whopping 66 per cent.. Yes, that’s right: another flop to add to the ever-growing list of failed AGW models. Worth noting in this latest alarmists’ retreat is that scant mention is made by alarmists of the several volcanic hotspots playing a significant role in melting the glacier from the bottom up, not the top down, as would occur with atmospheric warming. When it comes to fear-driven grant-snaffling, assailing SUVs and air conditioners as the prime cause of Gaia’s anguish is a much sexier and saleable scenario.
Amid all the variables one thing remains certain: you may withhold your child’s antidepressant medication tonight and settle them into bed with a comforting promise that there will be plenty of polar ice for them in the morning — and the foreseeable future.
When we wake up in the morning after a good night’s sleep, our height is up to a centimetre greater than when we go to bed in the evening after a day on our feet. This indicates that the smallest acceptable unit to measure height is a centimetre. Any smaller unit of height would be covered by natural variation and therefore tell us nothing.
When I drive to my daughter’s farm which is about 200 km south of Perth, my GPS system tells me the distance in kilometres. So the smallest reasonable unit of distance when going on a long drive is a kilometre. Any smaller unit, say a metre, would be covered by natural variation and therefore tell us nothing.
When we get to climate, we should be asking ourselves what is the smallest reasonable measure of time against which climate change can be measured. None of us would accept a day, or a week, or even a year. I have lived in Perth for more than 70 years. When I was a lad at school I learned that Perth had a Mediterranean climate. Now, Perth still has a Mediterranean climate. Nothing much has changed. Some years are a bit hotter, some are a bit colder, some are wetter, some are drier. But we still get four seasons, hot dry summers and cool damp winters.
I would suggest that the minimum unit of time against which we can measure climate change is at least a couple of hundred years, and probably a lot more than that, given that the earth has been around for about 4 billion years. Anything shorter than that is just natural variation in the weather and therefore tells us nothing about the climate. If we accept that 250 years is a minimum unit of time against which to measure climate change, then we are looking at 8 or 9 generations into the future before we notice it.
Given we are the most adaptable species on the planet, I think we can manage any such change.
Thanks to Greg Williams for his pertinent comments on time scales and distance scales. As far as I am concerned, living in Mornington, the relevant distance scale is the Mornington Peninsula. The weather in the Western suburbs and the Dandenongs and north of the Dividing Range is rather different. And the rest of Australia is simply not relevant to the weather that affects my daily life. My time scale is based on next week and the four seasons each year, going back a few decades for those with childhood memories.
For climate, however, the distance scale is global as long as the Earth keeps turning, and the Sun and Moon keep interfering. The time scale is centuries and millennia, and even longer to encompass the recurrent ice ages.
As far as my life style is concerned, weather is local on a time scale of decades, climate is global on a time scale of millennia.
I assume the opposite of an ‘activist’ (boo!) is a couch potato. I plead guilty therefore to both activism and warmism. While I would also sincerely hope that Jack Weatherall is right, but I am not prepared to bet my own or my family’s future on it.
I put it to readers that the planet is on a warming trajectory, and that the warming shows up not in thermometer readings, but in sea-level rise, coming largely out of glacier melt, and loss of land ice mass in polar and alpine regions. (I have cited this stuff before on this site. But then again, Weatherall’s article is by no means the first AGW denialist piece it has run either.)
Global Mean Sea-level (GMSL) Rates
CU: 3.3 ± 0.4 mm/yr
AVISO: 3.3 ± 0.6 mm/yr
CSIRO: 3.3 ± 0.4 mm/yr
NASA GSFC: 3.2 ± 0.4 mm/yr
NOAA: 3.2 ± 0.4 mm/yr (w/ GIA)
So if we do the arithmetic: 3.3 ± 0.4 mm/yr (CSIRO) ~ 33mm/decade (= 3.3 cm/decade ~ 33 ± 4 cm/century ~ 330 cm/1,000 yrs: ie 3.3 metres/1,000 yrs
~ 33 metres/10,000 yrs. Globally.
Thus the melting has not been going on historically for very long, otherwise the Ancients globally would have noticed and recorded it, and there would also be plenty of geological evidence. And that is without the great hunk of Antarctica’s Totten Glacier slowly but steadily sliding into the sea.
The University of Colorado Sea-level Research Group derives its sea-level stats from satellite altimetry whose reference point is the geographic centre of the Earth.
http://sealevel.colorado.edu/
The subtext never mentioned in all of this: nothing must impede the flow of coal into the power station furnaces, nor the flow of $$$$ into the bank accounts of those who have secured rights of private ownership of it. This IMHO is opportunist short-term thinking at its very worst. The coal deposits we have today took millions of years (chiefly in the Carboniferous and Permian) to lay down, and we can safely assume that to be a never-to-be-repeated process. They have far better long-term uses than power-station fuel, such as reduction of iron ore (as coking coal) and feedstock for the chemicals industry.
Thus pieces like Wetherall’s actually provide a pretty good case for state ownership of mineral resources; which I suppose makes me an activist warmist resource socialist.
In Australia, with very few exceptions, all minerals in the land are owned by the Crown, which sells the rights to them.
Trollster’s silliness is set in concrete, so answering it is without sensibility. Been there, done that.
It would be nice though if he actually learned some basic geoscience:
https://www.ga.gov.au/data-pubs/data-and-publications-search/publications/australian-minerals-resource-assessment/coal
Salome is correct of course. The Crown is in fact the State Governments. For the two territories, the Federal Govt.
To Ian Mc: zzzzzzzzzzzzzzzzzzzzzzzzzzzz
It’s not the polar icecaps that are melting, it’s only the snowflakes who inhabit our cities and infest the grant troughs of academia.
The warmists then and the warmists today differ markedly in their comparative moods. Whereas the warmest now are textbook gloomsters, whereas the warmists then seem positively excited that the arctic ice may melt.
I spent some time in Canada over the Xmas holidays, they have a great noun, Assclown:
From the Urban Dictorary, Assclown (North American): Someone who doesn’t know what the hell they are talking about, makes stupid BS comments, pisses people off, and has no idea that everyone thinks this about them.
Sound like anyone?
But Ian MacDougall’s figures, above, are consistent with ongoing post-Ice Age warming. Sea levels have been rising constantly since then, as the planet slowly warms, and this has been recorded, although inconsistently. Our continent’s original invaders recorded this with their feet, by crossing Torres Strait and then Bass Strait, something they’d have difficulty in doing today. But then there are apparent contradictions, such as the ancient Greek port of Ephesus, now quite a way inland from the Aegean Sea, although that can be explained by local hydrology. Meanwhile, other parts of the Mediterranean show pretty dramatic examples of sunken cities. It’s been known for some time that Australia’s eastern coast is sinking, partly explaining why sea-levels there seem to continue rising. The Pacific in places demonstrates zones of uplift, with dramatically exposed old atolls (makateas), while elsewhere, new atolls are still developing, either from sinking oceanic floors, or rising sea levels. Charles Darwin explained all this brilliantly more than 150 years ago, before plate tectonics had even been imagined. For me, there’s no doubt that our planet is warming, ice masses are melting, and general sea-levels are slowly rising; the real challenge is determining how much of this is “natural”, and how much is driven by human activities. And growing human populations are posing far more serious challenges, right now, than any gradual shifts in climatic patterns (unless you happen to own seaside real estate!).
norsaint: perhaps between snoozes you might have a look at https://www.theguardian.com/environment/2020/feb/15/worst-case-scenario-2050-climate-crisis-future-we-choose-christiana-figueres-tom-rivett-carnac#comment-138251776
(CAUTION: Source: [choke! caaargh! splutter! hawk! spit!*] THE GROAN!!! )
The most powerful argument in favour of AGW denialism I have so far encountered is that it simply cannot be happening; because if it was, it would be bad for established business, and especially for the coal business.
Its true that Prof Hansen does show an acceleration in sea level rise in his homogenised data.
However if raw data is used there is no acceleration of sea level rise.
Assuming a gradual increase in sea level as the oceans warm and glaciers melt after the LIA, one can set up a null hypotheses.
‘There is no difference between the present rate of sea level rise post the warming from the LIA and that which would occur with an increase in CO2 atmospheric concentration caused by additional Anthropogenic CO2.’
On then can see how important it is for those who believe in catastrophe that sea level will be barreling away.
There should be an acceleration of the rate of rise of sea level.
Just look to the data.
https://wattsupwiththat.com/2018/05/22/changes-in-the-rate-of-sea-level-rise/
Have a look at how it has been cherry picked.
The interesting thing is that Antarctic ice mass has actually been increasing, by some papers,
https://www.nasa.gov/feature/goddard/nasa-study-mass-gains-of-antarctic-ice-sheet-greater-than-losses
And that’s NASA.
But under the CO2 hypotheses both poles should be warming, and fast,as most of the warming affects the poles, not the tropics.
So, as this has failed to happen, warming must have another mechanism than us.
Maybe we are not the centre of our universe.
“The most powerful argument in favour of AGW denialism I have so far encountered is that it simply cannot be happening; because if it was, it would be bad for established business, and especially for the coal business.”
This needs a reference. Who said this, where was it said and when?
I feel the main players in the alarmist stakes, those with considerable investments in renewables for example, already are aware of a climate shift toward cooler temperatures when all their dire predictions will become ludicrous. Hence the need for action now rather than allow the plebs to find out they have been hoodwinked. They desperately need the subsidised gravy train enshrined in law before the frosty winters come and create food shortages.
Spot-on Lawrie. Ever-falling temperature due to the Grand Solar Minimum is the thing that will finally shake the Green/Left loonies and rent-seekers out of their crazy belief in AGW.
LPB:
“But under the CO2 hypotheses both poles should be warming, and fast, as most of the warming affects the poles, not the tropics.
So, as this has failed to happen, warming must have another mechanism than us.”
Since CO2 is well-established as a heat-trapping gas, and since also that its atmospheric concentration has risen about 40% above normality over the level it was at the start the Industrial Revolution (C 1750) there is likely to be heat trapped in the system somewhere. There is a basic law of nature that says the trapped heat cannot just disappear down some cosmic plughole.
I can think of one or two possibilities, but as I am not a meteorologist, climatologist or polar expert, I leave that issue to others.
Bernard:
That is the subtext underlying all AGW denialism, IMHO.
In other words, you have not encountered this argument, as you claim, but you are making it up to suit your purposes. Your HO is not that honest, here. How much more of the whole AGW argument works in the same manner?
Bernard:
“In other words, you have not encountered this argument, as you claim, but you are making it up to suit your purposes.”
Pure pedantry on your part; particularly given this site’s de facto role as mouthpiece for the coal industry, and accordingly, opponent of renewables; but without any masthead proclamation of that. (My own favourite is Coal, There’s Just No Alternative, by Tony Thomas.)
When your outrage subsides, ask your teacher for permission to google that up. Or just follow the link below.
.
https://quadrant.org.au/opinion/tony-thomas/2014/09/coal-theres-just-alternative/
Ian, how did you calculate “normality” in “40% above normality “?
Oh, look over there!
The fact is that your claim that you have “encountered” this view is dishonest. Keep up with the abuse and the infantile nonsense.
A little difficult to digest all this. During the carboniferous era we had in excess of 2000ppm of co2 with no runaway global warming, followed by a deficiency due to co2 uptake of plant life and a subsequent reduction in plant growth. Plants become co2 deficient when levels drop to 150ppm co2. So how all of a sudden does 450ppm co2 plus becomes an issue.
gavanhe,
The best site I know on climate history is http://www.scotese.com/climate.htm .
For the first time in its entire history (at least since its ‘Snowball Earth’ phase) thanks to the Arctic Ocean being essentially landlocked and Antarctic Continent providing a secure base for the Antarctic ice, the Earth has ice at both poles. This in turn has trapped methane as clathrates, particularly in the Arctic.
The danger some scientists see in this is that methane is a greenhouse gas of about 40 times the potency of CO2, and conceivably could lead to runaway global warming. Only one way to find out for sure….
We of this generation did not choose to mine and burn coal. Our ancestors in their day found it handy, and thought burning it to be a good idea. The Industrial World is now hooked on it, just as thoroughly as a junkie is on his heroin.
But it gets worse. We have gone from 280ppm CO2 in the atmosphere to the present 415 ppm since the start of the Industrial Revolution (1750). moreover, those in the mining game who have secured proprietary rights to the coal have a vested interest in global warming denial, and no shortage of funds with which to bankroll it where they see fit. So thereby, they influence public information as hard as they can, just as but in a more extreme way, the Stalin gang did in the old USSR, and Dr Goebbels did in Nazi Germany.
350 ppm is arguably a target to head for.
https://350.org/science/
Oh Dear, Mr MacDougall. In contrast to the vagaries of climate science, you have provided an example of the reliability of Godwin’s Law.