[Petrochemicals]

What is interesting and odd about the earth's climate is that the mean temperature of the atmosphere is cyclic, with very sharp rises followed by slow declines, within quite wide (± 2.1%) but very definite bounds. As the CO2 infrared absorption is saturated in the long wave region in our atmosphere, it cannot be the driver of  climate change and even if it were significant, we need a more powerful and nonlinear driver to explain the cycles.

Just to play devil's advocate, one could read that if co2 reaches critical levels it causes a global ice age.

[chiralSPO]

Quote from: chiralSPO on 29/10/2021 18:47:17

CO2 is probably NOT a driver of climate change historically

So when did the laws of physics change? The current warming cycle began about 20,000 years ago and so far looks pretty much like all the others, with CO2 following around 500 years behind a steeply rising temperature until very recently when the CO2 graph has accelerated.

Are you being intentionally daft? (I hadn't pegged you for a troll)

Nobody said the laws of physics changed (that's a straw man argument). Human activities changed. Most importantly, starting about 250 years ago, and accelerating nearly exponentially since then (is this the "fairly recently when the CO2 graph has accelerated" bit?): we have been extracting carbon that has been out of the atmosphere for several million years (ie orders of magnitude longer ago than the timespan of ice core histories), and converting it into carbon dioxide with great efficiency.

You might never believe it, but the amounts of coal, oil, and gas that have been extracted over the course of history have actually been documented quite well. (something about book-keeping, I dunno...) It also turns out that the ¹²C/¹³C/¹⁴C ratios in fossil fuels is different from that which was in the atmosphere up until we started burning them (ie in the ground, is old carbon, so is depleted in radioactive ¹⁴C, and ¹²C and ¹³C are fixed by photosynthesis at slightly different rates, and 100% of C in fossil fuels is from biological organics). Though nuclear weapons testing also disrupted atmospheric ¹⁴C levels a bit so...

So we can actually see (using CO₂ from the ice cores) how this isotope ratio has varied historically. And wouldn't you know it! It's been quite constant* for eons and only when we started digging up the other stuff and burning it did the concentration of CO₂ change significantly, AND the isotope ratio shifted. And, here's the really cool part. We can see from how much the concentration of total CO₂ has changed, and how much the ¹²C/¹³C/¹⁴C ratio has changed, and knowing the original atmospheric ratio ratio and the ratio in the ground, we can see that we are responsible for essentially 100% of the increase in CO₂, in the form of burnt fossil fuels.

https://www.climate.gov/news-features/climate-qa/how-do-we-know-build-carbon-dioxide-atmosphere-caused-humans


RubinoCO2Isotopes.jpeg (54.01 kB . 750x462 - viewed 2815 times)

F1.large.jpg (126.41 kB . 1280x803 - viewed 2805 times)

*Isotope ratios associated with other changes in historical CO₂ concentration do not appear to be the same in magnitude nor flavor. (for example, the last deglaciation:  https://www.pnas.org/content/113/13/3465)

[Bored chemist]

You might never believe it, but the amounts of coal, oil, and gas that have been extracted over the course of history have actually been documented quite well. (something about book-keeping, I dunno...)

On the whole, governments have been quick to latch on to the idea of taxing fossil fuels one way or another- they tax the companies that produce it and they tax the consumers too.
And so the tax records are a good indicator of fossil fuel use.

And, of course, the mines and drilling rigs were all happy to say how successful they are at producing oil, coal and gas.
Since practically all of it gets burned, that's good measure of the CO2 we put into the air.

Unsurprisingly, it tallies with the carbon isotope ratio evidence.

There really is no way round it; we put the CO2 into the air.
We know this, and can prove it.
We have the receipts.

And the laws of physics- which Alan insists have not changed- tell us that CO2 contributes to the green house effect.

So the only thing that needs "magic", is his view that we aren't responsible for the green house effect (and the fastest rise in temperature in at least 20,000 years)

https://xkcd.com/1732/

[Petrochemicals]

The trouble is with co2 is things like this.


202107_Percent_of_global_area_at_temperature_records_-_Global_warming_-_NOAA.svg.png (115.12 kB . 1365x1024 - viewed 1810 times)

Not just cold, record cold in the midst of man-made co2 increace.

[Bored chemist]

The trouble is with co2 is things like this.

More CO2 traps more heat in the Earth's atmosphere.
That drives more extreme weather and that's what we observe.

From our point of view, more extreme weather is certainly "trouble".
We even have a term for it.
https://en.wiktionary.org/wiki/global_weirding

[chiralSPO]

The trouble is with co2 is things like this.


202107_Percent_of_global_area_at_temperature_records_-_Global_warming_-_NOAA.svg.png (115.12 kB . 1365x1024 - viewed 1810 times)

Not just cold, record cold in the midst of man-made co2 increace.

Um.... this graph is in PERFECT agreement with global warming!

According to this graph, in the mid 20th century, it looks like between 1 and 6% of locations around the world would break its local cold record, and <1% of localities broke heat records. These neatly trade off during the last bit of the 20th century, and now virtually no places are break cold records (<1%), and 5–10% are breaking heat records!

It's important to note that these "records" are things like: "the coldest March 3rd in Berlin" (since records began a couple hundreds years ago), so it's not like 1955 was an ice age "in the midst of a man-made CO₂ increase"

Even if the average temperature and standard deviation were unchanged, we would still periodically expect records to get broken as time goes on (with more and more time between records). The fact that cold records are effectively stopped getting beaten, and heat records are getting broken more and more often (and by larger margins) means that the mean temperature has moved UP!

[alancalverd (OP)]

So why can't you apply the same idea to the rate of change of global temperature, a slow smooth input from orbital variation  and CO2 release as the positive feedback element?

Because (a) the waveform of a relaxation oscillator is the inverse of the temperature cycle  and (b) effects usually follow causes.

Even if CO2 were a plausible driver of historic temperature, we still need to find a reason why its concentration varied in the way it did.  The ash deposits rule out volcanic activity as a significant contributor.

[alancalverd (OP)]

Only an idiot would pretend that the climate hasn't changed. But a scientist would ask why, and seek an answer that explains previous changes.

[chiralSPO]

Only an idiot would pretend that the climate hasn't changed. But a scientist would ask why, and seek an answer that explains previous changes.

You know, traffic accidents kill millions per year globally, and the rate has been increasing more or less exponentially over the last 80,000 years. The trend is most obvious over the last century or two. "Only an idiot would pretend that it hadn't. But a scientist would ask why, and seek an answer that explains previous changes."

Please, with millions of lives on the line, can't any scientist provide an answer that explains the extreme recent uptick in roadside mortality AND also explains the the millennia of migratory misery? Of course, by Occam's Razor, the causes MUST be one and the same because that's the simplest explanation! (besides, otherwise, if we considered multiple causes, a slippery slope would require us to come up with a different cause for each death, and that's just not practical)


Oh, wait sorry, what's that? That doesn't make sense?

[chiralSPO]

You'll note that I have split this topic from the original thread because this side discussion had taken over. I will keep the thread in The Environment for now, but be warned: I may move it over to New Theories or That CAN'T Be True if it continues to devolve.

[Petrochemicals]

The trouble is with co2 is things like this.


202107_Percent_of_global_area_at_temperature_records_-_Global_warming_-_NOAA.svg.png (115.12 kB . 1365x1024 - viewed 1810 times)

Not just cold, record cold in the midst of man-made co2 increace.

Um.... this graph is in PERFECT agreement with global warming!

I said CO2, I did not say global warming. It does not support cow being the source of global warming. It would be in agreement with global warming starting at the 1980s. You must look elsewhere for the cause, it is not co2

[chiralSPO]

I am glad you agree that this graph represents a rapidly warming climate. But I don't think it indicates that things started in the 1980s. One can clearly see that cold weather records are decreasing across the whole of the chart and heat records are increasing across the whole of the chart. That there is an apparent crossover in the 1980s does not mean that the trend started then. And even though the graph starts in 1951, I bet these trends show up (with some ups and downs) extending back another 50 years. Before that the CO₂ were significantly less, and had less time to accumulate energy (bringing me to my next point)

Again, it appears that you are forgetting about the significant lag time between CO₂ emissions and the associated temperature increase due to the greenhouse effect of that CO₂. Even if the concentration of CO₂ stopped growing right now, temperatures would likely still increase for at least a century. Again, I would point you to this previous argument of mine:

But a sudden change in one parameter can often lead to a slow change in others. Like plugging the drain of a running shower. The water keeps flowing in at a steady rate, and the drain stopper was only added once, a few minutes ago, so why does the water level continue to rise?

[Petrochemicals]

I am glad you agree that this graph represents a rapidly warming climate. But I don't think it indicates that things started in the 1980s. One can clearly see that cold weather records are decreasing across the whole of the chart and heat records are increasing across the whole of the chart.

Yes cold records reducing, but the key word is "record", I would be hard pressed to say cold records is a signifier of warming, a record is an increace  on before, such as athletics, usain bolt did not set a less fast time, he increased the speed of the record. Up u til 1980 cold records are still being made and hot records have not increaced. The cross over seems to be around 1986.

It cannot be animals, animals have been here for ever, co2 and methane in con parable numbers, the only thing that seems to shadow this curve is human population.

[Bored chemist]

We have put more CO2 in the air. (we have the tax bills to prove it)
It is a greenhouse gas. (and as has been explained, it doesn't matter if the transitions are saturated- though, in fact, they aren't)
How would you expect anything other than a temperature rise?

It can't just be Milankovitch cycles because

Milankovich is all very well but orbital shifts and axial tilts tend to be sinusoidal, or at least time symmetric, not sawtooth.

So Alan has ruled out the only plausible external driver.

And since we have found a rise over the right timescale and about the right range, why not accept that it's cause and effect?

[Bored chemist]

"Why can't water vapor be the driver of today's climate change?"
Because it falls out of the sky when there's too much of it.
This is not news to anyone in the UK.
It did it a thousand years ago, and it still does it today.
So the  amount of water in the air is essentially fixed .

It can, of course, be "driven", but it can't be the driver.

[Origin]

Even if CO2 were a plausible driver of historic temperature, we still need to find a reason why its concentration varied in the way it did.

Historical causes of warming are beside the point, what humans are doing is a unique situation.

[chiralSPO]

I am glad you agree that this graph represents a rapidly warming climate. But I don't think it indicates that things started in the 1980s. One can clearly see that cold weather records are decreasing across the whole of the chart and heat records are increasing across the whole of the chart.

Yes cold records reducing, but the key word is "record", I would be hard pressed to say cold records is a signifier of warming, a record is an increace  on before, such as athletics, usain bolt did not set a less fast time, he increased the speed of the record. Up u til 1980 cold records are still being made and hot records have not increaced. The cross over seems to be around 1986.

It cannot be animals, animals have been here for ever, co2 and methane in con parable numbers, the only thing that seems to shadow this curve is human population.

Again, look up what those records actually are. They are highly localized in time and space, like "this is the lowest temperature recorded on a November 2nd in Cardiff since 1863" Also, note that our records extend only very far back. We are NOT saying that the Earth reached the lowest (or highest) temperatures ever in it's multi-billion year history.

Because the weather has a lot of randomness to it, we expect that this kind of record highs and lows would be set with some frequency, even if there was no overall change.

Now, there IS an overall change, and we can see that because the ratio of record highs to record lows is changing.

[Petrochemicals]

.

Now, there IS an overall change, and we can see that because the ratio of record highs to record lows is changing.

Yes.

Carbon dioxide is a gas that by your own admission has been rising for a lot longer than mid 80s. Co2 is also a gas that is easily returned from the atmosphere. You can use co2 in agriculture to increase plant growth, there must be some other potent gas that man has been producing collectivley in vast quantities, a gas that dwells after discharge and does not get removed from the atmosphere.

[Bored chemist]

there must be some other potent gas that man has been producing collectivley in vast quantities, a gas that dwells after discharge and does not get removed from the atmosphere.

OK
Here is the list of possible suspects.
Which one are you blaming?
https://en.wikipedia.org/wiki/List_of_gases

[chiralSPO]

Well, it's true to some extent: Anthropogenic emissions of methane (CH₄), volatile halogenated hydrocarbons (like CFCs, HFCs and low-boiling chlorinated solvents), and sulfur hexafluoride are all contributing to the greenhouse effect. Many of these compounds have very long half-lives in the atmosphere, and can, over the course of centuries, have many, many times the impact of CO₂, molecule for molecule (or pound for pound). This is reflected by a number called the global warming potential (GWP), often expressed as how many kg of CO₂ emissions one kg of gas emissions is "equivalent to" over a 100-year timespan.

https://climatechangeconnection.org/emissions/co2-equivalents/
https://climatechangeconnection.org/wp-content/uploads/2014/08/GWP_AR4.pdf

SF₆ is one of the most concerning because it is so effective at trapping heat and is virtually invincible. Luckily, current atmospheric levels have only reached parts per trillion levels so far.
https://www.advancedsciencenews.com/sf6-worries-the-most-potent-and-persistent-greenhouse-gas/

At this point CO₂ is still the primary emission responsible for the greenhouse effect observed so far. This is for three reasons: (1) we have been emitting it far longer than any of the other gases, (2) we are releasing many orders of magnitude more of it than any other gas (≈10¹² kg in 2020; that's about the mass of water in one million olympic swimming pools!), and (3) much of the difference in global warming potential of the gases comes from how long they stay in the atmosphere. (SF₆ is predicted to have a half-life of >3,000 years, and CF₄ is >50,000!!!)

So, even though one kg of SF₆ is listed as being at bad as 20,000 kg of CO₂, most of that difference will only be observable after many decades (or centuries), and at 420 ppm vs 10 parts per trillion, even counting the whole 20,000:1 ratio up front would mean that the total greenhouse warming potential of the SF₆ is still more than 2000 times greater.