Post by: alancalverd on 24/01/2021 23:21:41
The timescale reads from left to right and three features are strikingly clear
The temperature rises are very steep compared with the asymptotic falls, indicating a positive feedback mechanism in play
The temperature curve always leads the CO2 curve, implying that CO2 is an effect, not a cause.
The most recent feature shows a continuous steep rise in temperature beginning 25,000 years ago, with a few hiccups in the last 5000 years or so. On a geological scale, it is no different from previous steep rises.
These curves were published in the 2001 "Summary Report for Policymakers" of the IPCC but the anomalies were not highlighted or explained. I attended one of the early presentations of that report and quickly lost confidence in it as John Houghton (editor) introduced himself as a "committed Christian". I'm very wary of people who parade prejudice and superstition as a virtue: science isn't like that.
Moderator's note: This thread about interpreting historical ice cores was split off from "How could you stop the earth's poles from warming? (https://www.thenakedscientists.com/forum/index.php?topic=81483.0)", which is more forward-looking and action-oriented.
- Please post comments in the appropriate thread.
Post by: Bored chemist on 25/01/2021 13:48:04
( you might need a rather fine nib)
I prefer this chart.
https://xkcd.com/1732/
if you scroll to the bottom you will see what
The temperature rises are very steepmeans.
Post by: alancalverd on 25/01/2021 14:11:20
Lots of people are indeed talking about anthropogenic warming due to CO2, but a hypothesis based on a little recent correlation, that is not consistent with 400,000 years of coarse prior data, or explanatory of the cyclic fine structure of the Mauna Loa data, or the discovery of 500-year-old vegetation under a retreating glacier, doesn't fit into most people's definition of science.
"The last temptation is the greatest treason - to do the right deed for the wrong reason". T S Eliot. Not my favorite pseud by any means, but everyone is allowed to express one great truth!
Post by: Bored chemist on 25/01/2021 14:40:36
No, you can see a computer model of the future suggests.The bit up to 2016 is real data, not prediction; and it's steep.
Post by: Bored chemist on 25/01/2021 14:42:24
a hypothesis based on a little recent correlation, that is not consistent with 400,000 years of coarse prior data, or explanatory of the cyclic fine structure of the Mauna Loa data, or the discovery of 500-year-old vegetation under a retreating glacier, doesn't fit into most people's definition of science.What about a hypothesis based on the infrared absorption of CO2?
What you need to explain is how CO2 doesn't increase warming, when the science says it should.
Post by: Petrochemicals on 25/01/2021 15:37:31
Post by: alancalverd on 25/01/2021 15:44:42
Quote
The bit up to 2016 is real data, not prediction; and it's steep.Only a fool would pretend that climate doesn't change, and change quickly from time to time. Curious people might investigate an apparent correlation, but only a True Believer considers unidirectional correlation to be proof of causation.
Of course any gas increases warming, but since CO2 has always followed the temperature curve instead of leading it, and maximises on the Mauna Loa data in summer (when anthropogenic CO2 emission is least), how can anyone say it is the primary cause? On my planet, causes precede effects.
Just for a change, I concur with Petrochemicals (pity about the name!). What makes sense in my book is the effect of temperature on the activity of bacteria, fungi and coldblooded animals, which convert plant material into CO2 and both eat, and reproduce more, at higher temperatures. So after a sharp temperature rise you will see an increase in CO2 levels which persists with a lag (due to the increased population of said bugs) as the temperature decreases.
This nicely explains the Mauna Loa and the historic ice core anomalies.
Post by: Petrochemicals on 25/01/2021 19:12:33
There is alot of peat in the North tundra.
Post by: evan_au on 26/01/2021 03:08:59
Quote from: alancalverd
The temperature curve always leads the CO2 curve, implying that CO2 is an effect, not a cause.
Quote from: Euan Mearns
The air bubbles trapped by ice are always deemed to be younger than the ice owing to the time lag between snow falling and it being compacted to form ice. In Vostok, the time lag between snow falling and ice trapping air varies between 2000 and 6500 years. There is therefore a substantial correction applied to bring the gas ages in alignment with the ice agesIt seems that it is well-accepted that there is a time difference between the two measures, which must be calibrated out.
- There is likely to be arguments about how to account for this difference.
If I read him right, Euan Mearns is skeptical that humans are causing temperature rise today because they didn't 100,000 to 400,000 years ago. See blog (not peer-reviewed):
http://euanmearns.com/the-vostok-ice-core-temperature-co2-and-ch4/
Post by: evan_au on 26/01/2021 03:19:04
- Please post comments in the appropriate thread.
Post by: Bored chemist on 26/01/2021 08:39:48
Of course any gas increases warmingCan you explain the mechanisms for argon, oxygen and nitrogen please.
Post by: chiralSPO on 26/01/2021 08:58:11
The problem is that this historical data might not be a valid model for the last 250 years or so. If I understand correctly, for most of the history of our ice cores, nobody was excavating or extracting fossil fuels from deep below the surface, and burning them, at a rate of tens of billions of tons (1013 kg) of CO2 per year. It seems quite possible to me that this is unprecedented, and could be a significant departure from historical data.
Post by: chiralSPO on 26/01/2021 08:58:46
I saw that as well.Of course any gas increases warmingCan you explain the mechanisms for argon, oxygen and nitrogen please.
Post by: Bored chemist on 26/01/2021 11:25:34
What you need STILL to explain is how CO2 doesn't increase warming, when the science says it should.
Post by: alancalverd on 26/01/2021 11:36:58
They are all insulators.Of course any gas increases warmingCan you explain the mechanisms for argon, oxygen and nitrogen please.
https://upload.wikimedia.org/wikipedia/commons/7/7c/Atmospheric_Transmission.png shows the oxygen absorption spectrum and also the dominance of water.
Post by: alancalverd on 26/01/2021 11:45:06
The problem is that this historical data might not be a valid model for the last 250 years or so.Admittedly so, but any valid model must explain
the CO2 lag, both long term as shown in the ice cores and short term as shown at Mauna Loa
the steep and remarkably periodic historic temperature rise and slow fall, that was clearly not due to CO2
and if we reduce anthropgenic CO2 emission, the temperature must fall by a predicted amount in a predicted time to validate the hypothesis.
Which is why I proposed a zero-cost, reversible and negligible-impact method of reducing anthropogenic CO2 by 25% in about 5 years, several years ago. So far, nobody has dared to do the experiment. So either the climate crisis isn't that acute, or the hypothesis is known to be weak. My own opinion is that the crisis is a lot worse than any politician dares to imagine, and praying to the CO2 gods won't avert it. But five years is a lifetime in politics.
Post by: alancalverd on 26/01/2021 11:51:57
I never said it didn't. A squashed fly on my windscreen slows the car down, but that's no reason to ignore the binding brakes.What you need STILL to explain is how CO2 doesn't increase warming, when the science says it should.
Post by: Bored chemist on 26/01/2021 11:53:24
You mean that, if you get a big ball of rock, and enclose it in an insulator which allows radiation through from the Sun, the ball gets hotter- a bit like... a greenhouse?They are all insulators.Of course any gas increases warmingCan you explain the mechanisms for argon, oxygen and nitrogen please.
And they were insulators a thousand years ago.
So, how do they make the place warmer than it was a thousand years ago?
Post by: Bored chemist on 26/01/2021 11:54:24
A squashed fly on my windscreen slows the car down,If the fly weighed a third as much as the car, it would probably be significant.
Post by: Bored chemist on 26/01/2021 11:55:16
Which is why I proposed a zero-cost,Yeah; right...
Post by: Bored chemist on 26/01/2021 12:02:19
shows the oxygen absorption spectrumNo
It shows the oxygen and ozone absorption.
The Ozone massively dominates.
The O2 molecule isn't polar, it hasn't got a "handle" for IR to hold onto and it doesn't absorb IR.
Post by: alancalverd on 26/01/2021 14:57:04
So, how do they make the place warmer than it was a thousand years ago?They don't. It's the water that changes things significantly, just like it has done every 100,000 years, as far as we know.
Post by: alancalverd on 26/01/2021 15:08:24
The Ozone massively dominates.and as long as the sun shines and there's oxygen in the stratosphere, the ozone will continue to dominate where water doesn't.
The O2 molecule isn't polar, it hasn't got a "handle" for IR to hold onto and it doesn't absorb IR.Scarcely relevant since H2O absorbs or reflects so much of the IR spectrum and has 300 times as much heat capacity as all the other consitituents of the atmosphere.
Post by: Bored chemist on 26/01/2021 16:36:27
and as long as the sun shines ...You will still have been wrong to say
shows the oxygen absorption spectrumAnd you will still have been wrong if there's ever no O2 in the air.
300 times as much heat capacity as all the other consitituents of the atmosphere.
Gas Specific heat capacity at constant pressure (J kg-1K-1)
Air 993
Argon 524
Carbon dioxide 834
Carbon monoxide 1050
Helium 5240
Hydrogen 14300
Nitrogen 1040
Oxygen 913
Water vapour 2020
Are you muddling latent heat with heat capacity, or are you just something like ten thousand fold wrong?
(Given that air is roughly 1% water and 99 % other stuff).
Post by: alancalverd on 26/01/2021 17:35:15
Including hydrogen and helium in your table of gases might make it relevant to the greenhouse effect on Jupiter but these gases are depressingly absent from the stuff I breathe.
Post by: Bored chemist on 26/01/2021 18:26:35
You mustn't ignore the fact thatI didn't- it was you who tried to lump it in with heat capacity.
And, the weather forecasters also don't ignore it- they are quite good at predicting rain.
They also consider it in climate modelling- for exactly the reasons you give.
So what point did you think you were making?
Including hydrogen and helium in your table of gases might make it relevant to the greenhouse effect on Jupiter but these gases are depressingly absent from the stuff I breathe.When you come back down to this planet, you will find about 5ppm of helium in the air. The hydrogen concentration is about a tenth of that.
BTW, neither of them is a greenhouse gas.
Post by: evan_au on 26/01/2021 20:32:32
Quote from: Bored Chemist
The O2 molecule isn't polar, it hasn't got a "handle" for IR to hold onto and it doesn't absorb IR.Could you explain something for me, please?
- Comparing O2 and CO2...
- Both have a linear shape
- Both are symmetrical, so there is no overall electric dipole
- And yet CO2 interacts more strongly with IR than O2?
Is there an internal electric dipole in CO2, or additional vibration modes (eg bending)?
Post by: Bored chemist on 26/01/2021 21:02:57
When an oxygen molecule O2 vibrates there's never a dipole.
There are a number of ways a CO2 molecule can vibrate.
If it bends then that gives it a dipole. If it vibrates in a way where the carbon stays still but the oxygens move symmetrically in and out there's no dipole change, so that vibrational mode doesn't absorb IR.
If it vibrates where the oxygens stay more or less still, but the carbon bounces between them then that has a change in dipole and it emits IR (and absorbs it).
https://en.wikipedia.org/wiki/Infrared_spectroscopy#Number_of_vibrational_modes
Obviously, hydrogen H2 has no dipole and it is still unpolarised when it stretches so it can't contribute to a greenhouse effect (even on Jupiter)
Technically, the half deuterated version HD can.
https://www.nature.com/articles/166563a0
Helium has even fewer options.
Post by: alancalverd on 26/01/2021 23:56:20
https://en.wikipedia.org/wiki/Sunlight#/media/File:Solar_spectrum_en.svg
The difference between the "space" spectrum and the "sea level" spectrum is massively dominated by the absorption of water, with CO2 very much an afterthought in the tail.
But don't let the facts spoil a profitable hypothesis.
Post by: alancalverd on 27/01/2021 00:15:38
If we ignore the CO2 lag and suppose that sudden increases of CO2 were responsible for sudden temperature changes, those of a curious nature would ask what caused those sudden bursts of CO2?
Obviously, volcanic activity. Which projected massive amounts of CO2 and dust into the atmosphere. So we look at the ice cores and see....that the dust maxima mostly coincide with temperature and CO2 minima.
Bloody Russians.
Post by: chiralSPO on 27/01/2021 03:21:12
Here's an interesting spectrum
https://en.wikipedia.org/wiki/Sunlight#/media/File:Solar_spectrum_en.svg
The difference between the "space" spectrum and the "sea level" spectrum is massively dominated by the absorption of water, with CO2 very much an afterthought in the tail.
But don't let the facts spoil a profitable hypothesis.
Exactly! The water part of the spectrum is saturated. That's why changes in water concentration don't have as significant an effect. On the other hand, where CO2 absorbs, the spectrum is NOT yet saturated, and therefore will be related to concentration. Also, I see these spectra are overlaid with the blackbody radiation of incoming solar radiation. I would highly recommend comparing to the blackbody spectrum of the earth too. You will find that the frequencies of IR that interact strongly with CO2 make up a very small portion of the incoming energy, and a significant portion of the outgoing.
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Post by: Petrochemicals on 27/01/2021 08:45:01
Post by: Bored chemist on 27/01/2021 08:55:54
The difference between the "space" spectrum and the "sea level" spectrum is massively dominated by the absorption of water, with CO2 very much an afterthought in the tail.
Do you remember me saying this?
I'm sure I have seen you failing to properly understand the idea of a saturated transition as you seek to explain why CO2 isn't important to climate change.
Well, that argument is much more nearly valid for water vapour.
So the change in net solar gain with water vapour in the air is smaller.
Post by: Bored chemist on 27/01/2021 09:00:00
, what frequencies does water emit radiation at during condensation?There's a law of physics which says that things (almost always) emit radiation at the same wavelengths that they absorb it.
So, the emission spectrum of the liquid water will look the same as the absorption spectrum.
https://en.wikipedia.org/wiki/Kirchhoff's_law_of_thermal_radiation
Post by: alancalverd on 27/01/2021 10:37:14
Exactly! The water part of the spectrum is saturated. That's why changes in water concentration don't have as significant an effect.So you say there is no positive feedback mechanism? And clouds don't affect surface temperature? You'd have a problem telling a meteorologist, whose career depends on knowing a bit about atmospheric water.
Post by: Bored chemist on 27/01/2021 12:01:42
So you say there is no positive feedback mechanism? And clouds don't affect surface temperature?I think you will find that what we say is... what we said.
Only MarkPawelek is naive enough to think that there's no positive feedback.
There are at least 3 major pathways for it
1 Ice is reflective
2 Methane trapped as hydrates would be a very potent greenhouse gas
3 water vapour
Post by: alancalverd on 27/01/2021 14:00:21
Post by: Bored chemist on 27/01/2021 19:21:49
So you say there is no positive feedback mechanism? And clouds don't affect surface temperature?Clouds provide a negative feedback mechanism.
Perhaps you should establish a consensus with yourself.
Post by: evan_au on 27/01/2021 21:28:45
Quote from: alancalverd
the cyclic fine structure of the Mauna Loa dataThis is a seasonal pattern.
Since it is less than 11 years, it is not talking about climate.
- For cycles of 1 year, you have to look for factors impacted by Earth's annual orbit around the Sun, rather than weather or anthropogenic greenhouse gases.
Quote from: alancalverd
Obviously, volcanic activityI don't see how volcanic activity can produce semi-periodic results.
There have been suggestions that some of the Milankovitch cycles could/should drive some of the Earth's climate behavior in semi-periodic ways.
- One of the more surprising suggestions was that the angle of Earth's orbit relative to the plane of the ecliptic varies over long periods. If Earth's orbit were aligned with the ecliptic, there would be more zodiacal dust hitting the Earth about every 100,000 years.
- Perhaps increased fine dust in the upper atmosphere could affect the dynamics of solar absorption?
See: https://en.wikipedia.org/wiki/Milankovitch_cycles#Orbital_inclination
Post by: alancalverd on 27/01/2021 22:52:48
Quote from: alancalverdYes, but it's wrong! The Mauna Loa CO2 peaks quite sharply in the northern summer, when anthropogenic emission is minimal, so there must be something out there which generates more CO2 than human activity, and more when the temperature rises.
the cyclic fine structure of the Mauna Loa data
This is a seasonal pattern.
Quote
QuoteQuote from: alancalverdI don't see how volcanic activity can produce semi-periodic results.
Obviously, volcanic activity
Neither do I, but those who say CO2 has been the historic driver of temperature have generally offered volcanic activity as the source of those sudden rises in CO2. I might accept that by sheer coincidence there have been huge peaks of volcanism almost exactly every 100,000 years and of almost identical magnitude, if only the dust traces supported that hypothesis.
Problem with the dust traces is that whilst they mostly peak fairly close to temperature minima, there is no clear lead-in. If dust caused low temperatures (and we know that is true in the short term for volcanic dust), you'd expect to see the dust level rise before the temperature started to drop, but it's almost as though nothing happens until the temperature is very close to a minimum, whereupon the dust level suddenly rises then drops again.
However I look at the Vostok data, it only seems to make sense if water is the driver of temperature, and biological activity generates more carbon dioxide when the temperature rises. Why the shape of the dust trace? I'm not sure, but if the planet is very cold, most of the water will be in the expanded ice caps so you won't get much rain falling in the unfrozen areas. Desertification, dust bowl, reduced albedo, and the cycle restarts.
Post by: Bored chemist on 27/01/2021 22:57:12
so there must be something out there which generates more CO2Winter?
Post by: alancalverd on 27/01/2021 23:31:23
Post by: Petrochemicals on 28/01/2021 09:51:23
Anyway, back to the ice cores.One thing you notice about the co2 graph is it builds slowly and then crashes, just like the temperature etc. If co2 is the cause of global warming, where does it all dissappear to so quickly if co2 is such a longterm problem?
If we ignore the CO2 lag and suppose that sudden increases of CO2 were responsible for sudden temperature changes, those of a curious nature would ask what caused those sudden bursts of CO2?
Obviously, volcanic activity. Which projected massive amounts of CO2 and dust into the atmosphere. So we look at the ice cores and see....that the dust maxima mostly coincide with temperature and CO2 minima.
Bloody Russians.
Post by: alancalverd on 28/01/2021 11:31:16
Archaeologists and geologists often draw graphs with time going into the past from left to right, as in reply # 29, because that is the order in which they discover it, whereas stuff actually happens in the conventional physics order shown in the OP here, with "more at the top".
Post by: Petrochemicals on 28/01/2021 13:56:24
Post by: Bored chemist on 28/01/2021 14:48:52
Not according to Mauna Loa. And AFAIK there have been 400,000 winters in the last 400,000 years, but only 5 large CO2 peaks.You seem to have forgotten what you were talking about.
My comment "Winter" was related to your point that
The Mauna Loa CO2 peaks quite sharply in the northern summer, when anthropogenic emission is minimal, so there must be something out there which generates more CO2 than human activity,So, that's the seasonal variation and the thing that changes the CO2 concentration is winter.
Strictly, it doesn't create CO2, it stops the uptake, but the effect looks the same.
And before you ask, yes, I know there are two winters every year.
There's also the problem that what you said
"there must be something out there which generates more CO2 than human activity"
implies that the variation due to seasons is bigger then the anthropogenic change.
You might have more success getting people to consider the OP if you didn't say that because the graph is pretty clear..
seasonal.jpg (96.94 kB . 1106x579 - viewed 3604 times)
Post by: alancalverd on 28/01/2021 14:58:17
Quote
the thing that changes the CO2 concentration is winter. Strictly, it doesn't create CO2, it stops the uptake,
So in winter, when anthropogenic emission is greatest and foliage uptake is least, I would expect the CO2 concentration to be higher than in summer. But as you can plainly see, it's actually the other way around.
Quote
There's also the problem that what you said
"there must be something out there which generates more CO2 than human activity"
implies that the variation due to seasons is bigger then the anthropogenic change.
You need to distinguish between change (differential) and sum (integral). All True Believers will tell you that atmospheric CO2 is very persistent, which is why the (presumed) anthropogenic contribution has accumulated year on year. I don't dispute that. My question is why does the northern hemisphere CO2 level increase more in summer than in winter?
Post by: Bored chemist on 28/01/2021 18:02:05
And before you ask, yes, I know there are two winters every year.It seems you didn't understand why you should ask.
https://en.wikipedia.org/wiki/Keeling_Curve#Results_and_interpretation
"The Keeling Curve also shows a cyclic variation of about 5 ppmv each year corresponding to the seasonal change in uptake of CO2 by the world's land vegetation. Most of this vegetation is in the Northern hemisphere where most of the land is located. From a maximum in May, the level decreases during the northern spring and summer as new plant growth takes CO2 out of the atmosphere through photosynthesis. After reaching a minimum in September, the level rises again in the northern fall and winter as plants and leaves die off and decay, releasing CO2 back into the atmosphere"
Post by: Bored chemist on 28/01/2021 18:07:10
You need to distinguish between change (differential) and sum (integral)OK, lets do that
If something changes from about 310 to about 410, that is a difference. It's a difference of about 100
If it changes from about 396 to about 407 that is also a difference- about 11
And since 100 is more than 11 your contention that the seasonal variation is bigger than the anthropogenic variation is plainly wrong.
Now, what did you think someone had integrated?
Post by: alancalverd on 28/01/2021 18:24:04
It's odd how Believers dismiss others as deniers, when it is the Believers who persistently ignore the data! For the umpteenth time, yes, the climate is changing. Yes, it must because it is inherently chaotic. And it always has, with sharp temperature rises every 100,000 years or so, followed by a slow decline. And on the basis of historic performance, we would expect to be in a rapid rise period about now.
I think you would agree that a scientific hypothesis must explain existing data and predict future data. The CO2-as-driver hypothesis manifestly does not explain historic data. The anthropogenic-CO2-as-recent-driver might hold water but so far we have only observed a one-way correlation with a trend that began several thousand years ago, which most scientists would say is "interesting, possibly consistent with previous data, but by no means proof of causation".
Post by: Bored chemist on 28/01/2021 20:01:01
The anthropogenic-CO2-as-recent-driver might hold waterAnd, for the third time; you still have to explain how it could possibly not do so.
Post by: evan_au on 28/01/2021 20:04:02
- I downloaded and graphed the CO2 concentration for the same years (2015-2020).
- Tasmania shows much less seasonal CO2 variability than Mauna Loa - so this is a local seasonal phenomenon, rather than a global atmospheric phenomenon.
- They also measure Methane and nitrous oxides at Cape Grim - methane has greater seasonal variability, nitrous oxides less variability.
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Quote from: CSIRO, Cape Grim
Carbon dioxide concentrations show seasonal variations (annual cycles) that vary according to global location and altitude. Several processes contribute to carbon dioxide annual cycles: for example, uptake and release of carbon dioxide by terrestrial plants and the oceans, and the transport of carbon dioxide around the globe from source regions (the Northern Hemisphere is a net source of carbon dioxide, the Southern Hemisphere a net sink).
The Cape Grim baseline carbon dioxide data displayed show both the annual cycle and the long-term trend.
See: https://www.csiro.au/en/Research/OandA/Areas/Assessing-our-climate/Latest-greenhouse-gas-data
Quote from: alancalverd
which most scientists would say is "interesting, possibly consistent with previous data, but by no means proof of causationThis assumes that scientists are dependent on observations only.
- However, climate science is now an experimental science, with climate experiments conducted "in silico" (in silicon, in a supercomputer)
- And results have repeatedly shown that if you remove human additions of greenhouse gases, but leave background levels (including volcanoes), then you remove the warming trend we see now. That is cause and effect.
- That is taken to the next level with studies that try to attribute particular extreme events to human-induced climate change. They run many scenarios with and without human greenhouse contributions, and can come up with an estimate like "This event is 30% more likely with human contributions to climate change".
See: https://en.wikipedia.org/wiki/Attribution_of_recent_climate_change#Detection_and_attribution_studies
Post by: alancalverd on 28/01/2021 22:32:21
Post by: Bored chemist on 28/01/2021 22:54:43
The problem with all simulations is that they give you the answer you want,That's why the weather forecast is always so good in Alan's world.
The forecasts are mathematical simulations and, according to Alan, they will predict just the weather you want.
Other realities are available.
Post by: Bored chemist on 28/01/2021 22:56:13
Or you could start with the data and use a bit of AI to generate the model.Why not use real intelligence?
You know- stuff like actual physics where we can put in parameters like the absorption spectrum of CO2.
Post by: alancalverd on 28/01/2021 23:23:55
If I look to the future, it is clear that the temperature has been rising rapidly for the last 25,000 years or so, with or without human intervention, on pretty much the same shape curve as all previous cycles. Therefore it makes sense to plan for a future where global temperature is at least as high as it has ever been in the last million years. Faffing about measuring CO2 is "weighing the pig". It would be scientifically interesting and economically sensible to reduce anthropogenic CO2 before we run out of fossil fuels and it happens anyway, but it is far more important to plan for the humanitarian disaster that history suggests is inevitable, rather than blaming ourselves for what is entirely beyond our control.
I heard of a shareholders' meeting of a company that was in serious trouble. It was proposed to pay the directors in shares rather than money. Lots of pompous small shareholders took it in turns to complain about the dilution of their hundred or thousand shares, until a very old man stood up and said "I have five million shares in this company. I bought them at $15 and now they are worth 10 cents. Gentlemen, the plane is on fire and you are arguing about the pilot's salary."
Post by: evan_au on 29/01/2021 07:42:27
Quote from: alan calverd
you should be able to wind the clock back 400,000 years and generate the ice core dataIt comes back to the constants vs variables in your computer simulation.
- If you are going back 400,000 years, then the eccentricity and inclination of Earth's orbit become variables.
- Computer modeling has tried to match the Milankovitch cycles (and claimed some success), but it needs to be integrated with lags in the takeup of gases in rocks and other slow processes that are poorly understood.
However, to produce a valid climate forecast of the next 200 years (rather than 200,000), we can just leave these unknowns as constants.
See: https://en.wikipedia.org/wiki/100,000-year_problem
Quote
Actual physics begins with the observation that temperature leads CO2In the Cape Grim records, it appears that:
- daylight hours increase and temperatures rise from August to February, in the Southern Hemisphere spring & summer
- this leads to growth in oceanic algae, which absorbs CO2
- This is enough in most years to cancel the human-induced annual growth in CO2 concentration (and even reverse it, in some years)
- As winter approaches, the algae dies off, releasing some CO2 into the atmosphere, and taking some of it to the bottom of the ocean.
- This annual cycle of algal growth is independent of and superimposed upon human-caused greenhouse gas emissions.
But it is meaningless to talk of "lag" or "lead" in an annual cycle.
- "leads by 6 months" is identical to "lags by 6 months"
- And this sheds no light on a lag of thousands of years in the 100,000-year climate cycle. They are entirely different processes
Post by: Bored chemist on 29/01/2021 10:33:10
Actual physics begins with the observation that temperature leads CO2Actual physics of absorption of IR by CO2 began nearly a hundred years before the ice core data was known.
It also has the massive advantage of being amenable to experiment and testing.
Post by: alancalverd on 29/01/2021 15:18:54
- this [summer] leads to growth in oceanic algae, which absorbs CO2That's particularly interesting because you might expect Mauna Loa to behave pretty much the same way - fairly close to the sea and also surrounded by trees....but it doesn't.
Quote
If you are going back 400,000 years, then the eccentricity and inclination of Earth's orbit become variables.If Milankovitch is responsible for the most recent 25,000 years, that really does make CO2 seem irrelevant. The problem I have, however, is that all the Milankovitch inputs are sinusoidal and independent, so whatever the resultant waveform, you'd expect the resultant temperature curve over 400,000 years to be time-symmetric with variable peaks rather than a bounded sawtooth: something very nonlinear is going on.
Post by: Bored chemist on 29/01/2021 15:44:46
something very nonlinear is going on.Gosh!
Quote from: Bored chemist on 24/01/2021 10:58:03
Only MarkPawelek is naive enough to think that there's no positive feedback.
There are at least 3 major pathways for it
1 Ice is reflective
2 Methane trapped as hydrates would be a very potent greenhouse gas
3 water vapour
Post by: evan_au on 29/01/2021 21:21:44
Quote from: alan calverd
the Vostok ice core data that makes me skepticalYou should be skeptical of using a single data source for something which varies greatly in different locations at different altitudes at different times.
- We see that with CO2 levels and temperature at different points on the globe
- We see that with the Greenland ice cores, where the initial core gave misleading results until they repeated ice coring in very different locations at different altitudes, and compared them
- A bit hard for Lake Vostok, since it is at a single elevation and a confined location; but I guess they could take additional ice cores at other ice lakes in Antarctica to come up with a consensus
- Unfortunately, there are no surviving frozen lakes in Hawaii...
- Other useful data over 1 million+ years comes from the remains of microscopic sea life on the sea floor
See: https://www.carbonbrief.org/factcheck-what-greenland-ice-cores-say-about-past-and-present-climate-change
Post by: evan_au on 29/01/2021 21:51:40
Quote from: alancalverd
something very nonlinear is going onThis is true in general for chaotic systems.
It's especially a problem with climate and hydrodynamics, since the entropy of vortices spinning off other vortices gives a one-way arrow to time.
It is less of a problem with systems like motions of the planets, where kinetic + potential energy is conserved over time.
- The thing you can't account for is an "external" influence like a planet being ejected from the Solar system; the modeler doesn't know it was there, so their predictions beyond that point will be totally wrong.
At least for climate, we have a historical record stretching back over a million years, to which we can try and fit the known historical events.
- But it doesn't quite fit (yet), which is why modelers are trying to tackle potential external factors like the dust in the plane of the ecliptic.
- It has been suggested that we could seed algae in the oceans with essential minerals to soak up carbon dioxide
- Currently, Earth's orbit takes us through this dust on 2 days of the year.
- If Earth's orbit were taking up this dust 365 days of the year, that might provide an external input that feeds algae and soaks up CO2?
Post by: alancalverd on 29/01/2021 23:24:09
See: https://www.carbonbrief.org/factcheck-what-greenland-ice-cores-say-about-past-and-present-climate-change
You rarely disappoint me, Evan, but the last graph in that reference clearly substitutes prejudice for observation!
Quote
Indeed, but the consistency of the asymmetric sawtooth is not characteristic of chaos alone. It looks much more like a relaxation oscillator than a white noise source.Quotesomething very nonlinear is going onThis is true in general for chaotic systems.
BC sensibly pointed out that
1 Ice is reflective
2 Methane trapped as hydrates would be a very potent greenhouse gas
3 water vapour
but then reverted to the True Faith of carbon dioxide.
Never mind. At least the conversation made me think.
Post by: alancalverd on 30/01/2021 11:40:15
If I read him right, Euan Mearns is skeptical that humans are causing temperature rise today because they didn't 100,000 to 400,000 years ago. See blog (not peer-reviewed):I just got round to reading the paper. Didn't see the word "human" or "anthropogenic" anywhere, but a well-susbstantiated conclusion that
http://euanmearns.com/the-vostok-ice-core-temperature-co2-and-ch4/
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The only conclusion possible from Vostok is that variations in CO2 and CH4 are both caused by global temperature change and freeze thaw cycles at high latitudes. These natural geochemical cycles makes it inevitable that CO2 and CH4 will correlate with temperature. It is therefore totally invalid to use this relationship as evidence for CO2 forcing of climate, especially since during the onset of glaciations, there is no correlation at all.
So just to reiterate my concern: given that climate change is inevitable and beyond human control, what are we going to do to ensure that our descendants can enjoy a decent and peaceful standard of living?
Post by: Bored chemist on 30/01/2021 11:51:35
revertedWhat do you mean by "reverted"?
Post by: alancalverd on 30/01/2021 13:32:09
Post by: Bored chemist on 30/01/2021 14:59:17
revertedWhat do you mean by "reverted"?
Post by: chiralSPO on 30/01/2021 15:56:57
Is it reasonable to assume that the mechanism responsible for the slow return to baseline after the smaller CO2 spikes will be able to reverse the current level and trend? I don't think that previous returns to normal are necessarily good predictors of future behavior given how significantly we have deviated from the previous data.
Also, if I understand correctly, you accept that increased CO2 in the atmosphere will lead to buildup of thermal energy, just not an increase in temperature? (how I interpreted your multiple references to heat capacity and latent heat of water). Ok, let's say the temp doesn't increase at all. Where does the energy go? What does that mean for the climate?
Post by: evan_au on 30/01/2021 21:12:53
Quote from: alancalverd
Didn't see the word "human" or "anthropogenic" anywhere...Exactly my point!
- As I read it, Euan Mearns doesn't believe in "human"-induced or "anthropogenic" climate change.
- He works through various non-human mechanisms that may have affected Earth's climate in previous 100,000-year cycles (human hunter-gatherers being too small in number to be a significant contributor).
- And he tries to imply that humans can't be affecting the climate today, even though we have around 7 billion humans and a significant agro-industrial complex that didn't exist 100,000 years ago.
- Pardon my ignorance of Latin, but I think that is called a "non-sequitur"?
Quote from: alancalverd
the last graph in that reference clearly substitutes prejudice for observationI'm sorry that you didn't like the last paragraph - I thought the article was quite sensible about the need for calibration of your results from multiple sources.
- The last part was where the historical trend (over thousands of years) is calibrated and joined onto projections of the next 50 years (if we keep going as we are, vs if we can curb CO2 rapidly).
- Perhaps it would be better described as "adding extrapolation to observation".
- Passive observation does not lead to any action.
- Extrapolation of two scenarios does not passively wait for the future to become history (by which time it will be too late to do anything about it!), but encourages us to actively choose our path.
Post by: alancalverd on 31/01/2021 00:13:29
I'll work through the detailed energetics at a later stage, but it is worth noting that the 7 millibar partial pressure of atmospheric carbon dioxide on Mars is about 18 times than on Earth (0.4 mb) , and the mean solar heat input per unit area about 0.43 of the Earth value (from a 1/r2 calculation) so if CO2 is a dominant greenhouse gas and the absorption bands are not saturated, you'd expect Mars to be as warm as Earth. I've attached a table of the supposed relative contributions of greenhouse gases in our atmosphere and even if you take the most "favorable" ratio that CO2: other gases is 9:88, that still suggests that the greenhouse effect on Mars will be about twice that on Earth, even ignoring the absence of clouds. But it clearly isn't, which casts some doubt on the warming significance of CO2 in Earth's atmosphere.
And whatever hypothesis you prefer, I haven't seen one that seriously suggests a positive feedback mechanism driven by CO2. So the historic (and current, for 20,000 years) sharp rises in temperature must be due to something else, over which we have no obvious control. That's the problem for life on this planet, and praying to the carbon gods probably won't solve it.
On the one hand, working from an invalid hypothesis isn't always a Bad Thing. All the early work on the propagation of radio waves was modelled on compression of the aether, right up to the development of radar and television, and it would indeed be a Good Thing if society were less dependent on the burning of fossil fuels. But developing radar without developing fighter aircraft, or spending a huge effort on decarbonisation whilst ignoring the inevitability of climate change and sea level rise, would be beyond stupid.
Post by: evan_au on 31/01/2021 08:54:00
Quote from: alancalverd
you'd expect Mars to be as warm as EarthThe black body temperature of Earth is about -23C (about 250K).
- The average surface temperature is around +15C, so a greenhouse warming of around 38C.
The black body temperature of Mars is about -63C (about 210K).
- The average surface temperature is around -60C, so a greenhouse warming of practically nothing.
- Not so surprising since the atmospheric pressure on Mars is about 1% of Earth - a very thin blanket, indeed!
So even if there were no Greenhouse effect, you would expect Mars to be considerably colder than Earth.
But Earth's water vapor, methane & ozone make a significant contribution to Earth's habitability.
- Nobody denies that. It is believed that Earth suffered an extended "snowball Earth" fate in the long-distant past
- But increasing CO2 & fluorocarbons (also a potent and long-lived greenhouse gas, but now with reduced production) account for most of the changes seen in the past 70 years or so.
See: https://en.wikipedia.org/wiki/Snowball_Earth
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I haven't seen (a hypothesis) that seriously suggests a positive feedback mechanism driven by CO2.What about large areas of frozen land in arctic areas (eg Greenland & Canada). As the permafrost melts to a greater depth, microbes will become more active in the soil, producing CO2 and methane from stored carbon...
- That will further increase CO2, producing more melting.... (positive feedback)
What we want tis that the melting permafrost turns into a carbon sink, rather than a carbon source!
Post by: alancalverd on 31/01/2021 09:43:36
- Not so surprising since the atmospheric pressure on Mars is about 1% of Earth - a very thin blanket, indeed!But it is almost entirely CO2 - 18 times as much as Earth. So if CO2 is a significant contributor to the greenhouse effect, it will be 18 times as significant on Mars. As you say, the greenhouse effect on Mars is negligible, and one eighteenth of negligible is, in my maths, buggerall or less. Which implies that CO2 is not a significant contributor to the greenhouse effect on Earth.
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But increasing CO2 & fluorocarbons (also a potent and long-lived greenhouse gas, but now with reduced production) account for most of the changes seen in the past 70 years or so.Here's my beef. Coincident with? Certainly. Causative of? Not proven.
As you say, increasing temperature will generate CO2 from all sorts of sources. So CO2 follows temperature. But what triggers the initial temperature rise from the bottom of the curve?
Post by: Bored chemist on 31/01/2021 10:02:58
I haven't seen one that seriously suggests a positive feedback mechanism driven by CO2.Heating the oceans will cause them to lose CO2. It's slow, but it will happen.
Post by: Bored chemist on 31/01/2021 10:54:37
Here's my beef. Coincident with? Certainly. Causative of? Not proven.And here's my beef:
You know there were three blankets on the bed.
You know you have added a fourth
You know it is warmer.
and you ask "But where is the proof of causation?".
Well the answer is obvious: we know what blankets do.
Post by: Bored chemist on 31/01/2021 11:23:08
But it is almost entirely CO2 - 18 times as much as Earth.In the sense that 95 is 18 times bigger than 0.04?
What you actually need to compare is the number of molecules of CO2 that shade each square metre.
That's proportional to the mass of CO2 per square metre
And if I have done the arithmetic correctly (And I apologise for the fact that cut+ paste doesn't work well for spreadsheets- if anyone really wants, I will post an image) ...
Mars Earth RMM convert to m/m Mars Earth
mass atmos 2.50E+16 5.15E+18 Kg
% CO2 v/v 95.32 0.04 44 4194.08 1.76 %m/m 96.43806789 0.060716454
%O2 0.174 20.94 32 5.568 670.08 %m/m 0.128029785 23.11641
%N2 2.6 78.1 28 72.8 2186.8 %m/m 1.673952653 75.44019429
%Ar 1.9 0.93 40 76 37.2 %m/m 1.747532989 1.283325054
%H2O 0.03 0.16 18 0.54 2.88 %m/m 0.012416682 0.099354198
%CO2 m/m 96.43806789 0.060716454
Mass CO2 2.41E+16 3.13E+15
radius (Km) 3,389.50 6,371
Surface area 144344155.6 509968249.5
Kg CO2/Km2 1.67E+08 6.13E+06
ratio 27.24073449
There's 27 times more molecules of CO2 shading each square metre of Mars.
But then we need to actually look at the thing that the denialists bang on about without understanding.
The world of saturation of a transition.
Essentially, it's simple.
Imagine shining a beam of red light through some green liquid- say food dye in water.
Once the pathlength is long enough, virtually all the light is absorbed and so using a longer path doesn't absorb any more.
Equivalently, you could add more dye to the water. Once you have added enough to absorb almost all the light then adding more won't make any (meaningful) difference.
(And, as an aside I will just mention here that putting more blankets on a bed is also non-linear- how many would it take before the person reached 100C?)
However, imagine that instead of using red light , I used a beam of white light- a bit like sunlight.
It's true that the red light corresponding to the peak of the absorption would all be absorbed in the tank of green water, but the other colours would still get through.
And it's clear, if you think about it, that the broader the absorption of the light by the dye, the more light will be absorbed. And also- crucially- the more dye you would need to add in order to saturate those absorptions.
So broader spectra are less susceptible to saturation.
The absorptions of IR by CO2 (and there are lots of them) are all broadened by either increasing the temperature, or increasing the pressure.
And both the temperature and pressure are higher on Earth than on Mars.
So a given amount of CO2 on Earth does a better job of absorbing CO2
And that's all beside the point.
Earth is warm-
Part of that is because of radioactive rocks.
Part of it is simply what you would expect of a black body near the sun.- heat comes in: heat goes out.
Part of it is because we have an atmosphere that acts as an insulator.
Part of that in turn is due to the greenhouse effects of the various gases- notable CO2 an water vapour.
And, when you do some complicated maths you can work out how warm the planet should be.
And then you come to the tiny effect that we are talking about; warming.
We all know that, roughly speaking, the Earth is at about 15C (on average).
But the actual issue is not the temperature. We can explain that (as above etc.). Nobody cared what the actual balance of those factors is, because they were (on our timescales) constant.
The issue is the recent rapid change in temperature.
So the trillion dollar question is "what factors are changing, and which could explain the temperature changes we observe?"
And the only plausible one is the CO2 concentration.
Post by: alancalverd on 31/01/2021 12:43:44
What you actually need to compare is the number of molecules of CO2 that shade each square metre.Which is proportional to the partial pressure of the gas: 7 mb on Mars (OK, 7 hPa if you prefer!) versus 0.4 hPa on Earth. You need to account for the lower g of Mars, which will bring your figure closer to mine. So we agree on that, at least.
More about saturation later - I'm off to explore a bit of England at 900 hPa while the sun shines.
Post by: Bored chemist on 31/01/2021 13:25:33
Which is proportional to the partial pressure of the gas:And to the depth of the atmosphere which is different; which is why I did the slightly more complicated calculation, and got a better answer.
I'm off to explore a bit of England at 900 hPa while the sun shines.Have fun.
Let us know when you are back on the planet.
More about saturation laterNever mind that:
You really need to address this
Here's my beef. Coincident with? Certainly. Causative of? Not proven.And here's my beef:
You know there were three blankets on the bed.
You know you have added a fourth
You know it is warmer.
and you ask "But where is the proof of causation?".
Well the answer is obvious: we know what blankets do.
Post by: alancalverd on 31/01/2021 14:31:52
To address the saturation question, I'm now trying to find a solar input spectrum comparing stratospheric input with ground level to the 15 micron range (for Earth, not Mars). So far all those I've been able to locate have stopped short at about 2 micron. Any help you can give will be most appreciated! The reason is that all the transmission spectra I can find seem to show 0% upward transmission at 15 micron, indicating that the CO2 longwave band is indeed saturated, so adding a bit more CO2 won't make any difference.
Post by: alancalverd on 31/01/2021 15:07:42
If CO2 is the driver, and saturation isn't significant, there is no obvious maximum and no reason for the temperature to decrease. But it has done, several times.
If CO2 is the driver and saturation is significant, then the temperature is unlikely to exceed its present value by much because we are already close to the historic maximum set by saturation.
Post by: Bored chemist on 31/01/2021 17:28:44
But I realised of course with gM about 0.37 x gE, I've underestimated the molecular concentration of CO2 on Mars.Good to know that you can realise things when we point them out.
Post by: Petrochemicals on 05/02/2021 00:07:43
Post by: Bored chemist on 05/02/2021 09:13:40
Perhaps it's time for another question, sort of why does temperature fluctuate irrigardless of carbon dioxide.It is not time for a question which uses meaningless words.
Post by: Petrochemicals on 18/04/2021 22:58:24
https://www.iucn.org/resources/issues-briefs/land-degradation-and-climate-change
Post by: thelistener on 16/05/2021 19:44:10
I found an interesting German article on air quality at home which can easily be translated with Google translate.
I really got some nice tips out of it how to improve my health by increase the air quality in my room. Hope you can use them, too!
Post by: alancalverd on 16/05/2021 23:05:20
Post by: 4312 on 17/05/2021 14:45:03
Post by: MarkPawelek on 30/04/2022 11:28:11
Post by: alancalverd on 30/04/2022 11:51:26
I don't see AGW as intentional fraud but a very convenient hypothesis that, like religion, is profitable to promulgate and difficult to disprove. It even has the requisite elements of human guilt and necessary sacrifice.
The problem is what happens when self-flagellation doesn't avert the entirely predictable disaster. My preference is to take positive steps to mitigate the impact of climate change and not pin all your hopes on a flimsy hypothesis that contradicts historical precedent.
Post by: Bored chemist on 30/04/2022 12:47:34
but the shape of the curve for the last 15,000 years closely matches that of several previous cycles, lNo.
You need to stop saying that.
CO2 is rising a hundred times faster than ever before.
Measurements from older ice cores (discussed below) confirm that both the magnitude and rate of the recent increase are almost certainly unprecedented over the last 800,000 years. The fastest large natural increase measured in older ice cores is around 20ppmv (parts per million by volume) in 1,000 years (a rate seen during Earth’s emergence from the last ice age around 12,000 years ago). CO2 concentration increased by the same amount, 20ppmv, in the last 10 years!
from
https://www.bas.ac.uk/data/our-data/publication/ice-cores-and-climate-change/
Post by: alancalverd on 30/04/2022 21:41:04
CO2 is rising a hundred times faster than ever before.but temperature isn't. Because even if the CO2 greenhouse effect were far from saturation, temperature would depend on the total concentration, not the recent incremental rate of change.
Post by: Bored chemist on 02/05/2022 19:59:27
but temperature isn't.Yes it is.
https://earthobservatory.nasa.gov/features/GlobalWarming/page3.php#:~:text=As%20the%20Earth%20moved%20out,ice%2Dage%2Drecovery%20warming.
It's "only" 10 times aster, but it's faster.
Post by: alancalverd on 02/05/2022 22:59:20
No.
You need to stop saying that.
Not being a politician or a climate "scientist" I'm not interested in making comforting noises and pretending that everything will be OK if we stop generating carbon dioxide from fossil fuels or animal husbandry. Whatever we do on that score, history suggests that the next hundred years are going to be disastrous if we don't reduce the human population to something that can be sustained in a world some 3 degrees hotter than it is now.
It's "only" 10 times aster, but it's faster.Partial quote.The actual statement was that instrumental records suggest a recent peak rate ten times the estimated average for the past 5000 years. I haven't used my car for the last two days, so its average speed over the last 3 days has been about 0.1 mph. Tomorrow I will drive to work at a peak rate seven hundred times the estimated recent average. But it won't make any headlines.
Post by: Petrochemicals on 26/07/2022 09:18:12
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