[chiralSPO]

In that case there must be more more than co2 responsible for the vast majority of heat retention.

Well, the sun plays an important role too... (it's where the retained heat comes from)

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?

[alancalverd]

water is indeed the problem, and as the ice core data shows, always has been.

Got evidence?

The ice core data. Plenty of images available on the internet. They all show that for the last 400,000 years 

1. The CO2 curve lags some 500 years behind the temperature curve - effects usually follow causes

2.The temperature increases very rapidly then decreases slowly - indicating a strong positive feedback which CO2 does not exhibit

3. The temperature peak is remarkably consistent between cycles, consistent with cloud cover (i.e. water) being a limiting factor for insolation. If CO2 is the primary driver there is no reason why the peaks should be consistent nor why the temperature should decrease after reaching a short-duration peak

I know of no mechanism that can generate regular rapid rises followed by slow declines of CO2 apart from a cycle of plant/animal interactions mediated by temperature. Vulcanism has been offered but the associated ash deposits do not coincide with the major rises in CO2 concentration which follow the temperature curve.

CO2 is a convenient scapegoat because it is easy to measure and, to a very limited extent, is controllable, but there is no evidence that sending a goat into the wilderness ever solved a problem.

There are many good reasons to reduce anthropogenic CO2 emission, but it is foolish to think that this will bring about a substantial change in the temperature cycle.

[Bored chemist]

water is indeed the problem, and as the ice core data shows, always has been.

Got evidence?

The ice core data. Plenty of images available on the internet. They all show that for the last 400,000 years 

1. The CO2 curve lags some 500 years behind the temperature curve - effects usually follow causes

2.The temperature increases very rapidly then decreases slowly - indicating a strong positive feedback which CO2 does not exhibit

3. The temperature peak is remarkably consistent between cycles, consistent with cloud cover (i.e. water) being a limiting factor for insolation. If CO2 is the primary driver there is no reason why the peaks should be consistent nor why the temperature should decrease after reaching a short-duration peak

I know of no mechanism that can generate regular rapid rises followed by slow declines of CO2 apart from a cycle of plant/animal interactions mediated by temperature. Vulcanism has been offered but the associated ash deposits do not coincide with the major rises in CO2 concentration which follow the temperature curve.

CO2 is a convenient scapegoat because it is easy to measure and, to a very limited extent, is controllable, but there is no evidence that sending a goat into the wilderness ever solved a problem.

There are many good reasons to reduce anthropogenic CO2 emission, but it is foolish to think that this will bring about a substantial change in the temperature cycle.

So that's a "No" then
You do not have ice core evidence that says that water is responsible.

[alancalverd]

Evidence is one thing, and the ice core data is irrefutable.

Determination of responsibility is a matter of interpreting the evidence. I cannot find a rational interpretation consistent with CO2 being the driver of historic climate change.

Given the data we have, either water is the driver or some hitherto unknown agent decides that temperature should follow a sawtooth cycle and carbon dioxide should follow the same cycle 500 years later.

You are welcome to provide a different interpretation as long as it accounts for the data and identifies the driver.

[Bored chemist]

"

Evidence is one thing,

And what you presented is another; at least  in regard to what you said.
You actually said  this

water is indeed the problem, and as the ice core data shows, always has been.

The ice core record (ironically) does not tell you about water levels in the air.

If you really think it does then please give us a link.

I cannot find a rational interpretation consistent with CO2 being the driver of historic climate change.

Good point- sort of.
But inevitable and meaningless.

It is true that the historical record does not show CO2 leading a temperature rise.
But that's because, prior to mankind getting in on the act, there was no plausible source of CO2 that could materially affect the concentration in the atmosphere.

You will not see, at any point in Earth's history a record of what happened when mankind suddenly raised CO2 levels roughly 10 times faster than they have every risen before.
Because mankind never did it before.

That's more or less the point of anthropogenic climate change. Nobody ever did it before.
So it makes no real sense to look at the historical record for a precedent for "today's" events - say the last 200 years.
Historical climate change was not driven by anthropogenic CO2.

Nobody said it was.


But here's the actual explanation of the link between CO2 and climate.
TLDR version, it's not been the cause in the past; it has been an amplifier- a positive feedback mechanism  enhancing changes due to orbital effects.

But it still has the effect of creating warming, even if the initial source isn't orbital variation, but mankind.

[alancalverd]

prior to mankind getting in on the act, there was no plausible source of CO2 that could materially affect the concentration in the atmosphere.

So why did it fluctuate so much, just 500 years behind the temperature graph? There must have been a mechanism, and I think it tautologous that it must be a plausible one!

in the past; it has been an amplifier- a positive feedback mechanism  enhancing changes due to orbital effects.

So you assert that all the major temperature fluctuations in the last 400,000 years were due to sudden orbital shift followed by a gradual return to the preceding orbit,  and that the "amplifier" that made it worse turned up 500 years afterwards. That's stretching plausibility a bit, to say the least.

Why do I think "water"? Because it is known to be the most significant greenhouse gas, its absorption spectrum is very broad and not saturated, it exists in all three states in the atmosphere with huge latent heat changes between them, and there is (uniquely) a hell of a lot of it on the surface of this planet. "When you hear hoofbeats, think horses, not zebras".

[Bored chemist]

o why did it fluctuate so much, just 500 years behind the temperature graph? There must have been a mechanism, and I think it tautologous that it must be a plausible one!

Do you recognise that CO2 is less soluble in warm water?
Do you understand this idea?

it has been an amplifier- a positive feedback mechanism

So you assert that all the major temperature fluctuations in the last 400,000 years were due to sudden orbital shift

Why tell that lie?
It just makes you look foolish.
Anyone reading this thread knows that I never asserted that, did I?

[chiralSPO]

I cannot find a rational interpretation consistent with CO2 being the driver of historic climate change.

CO₂ is probably NOT a driver of climate change historically until we look way back to time periods FAR predating ice cores (ie last time the atmosphere had significantly more CO₂ there was no ice at the poles...

And unless there was some non-anthropogenic process capable of putting 10¹⁶ kg of CO₂ into the atmosphere in 150 years (practically instantaneous on geological timescale), there isn't likely another such event in the "historic" climate change

[alancalverd]

Do you recognise that CO2 is less soluble in warm water?

Absolutely. But why did the water get warm? Obviously not because of atmospheric CO2: you have to distinguish between cause and effect, and most people think cause always precedes effect. If the water warmed by whatever cyclic magic you imagine, and emitted CO2 that then accelerated the warming process, why did the temperature decrease whilst the CO2 concentration was at its maximum?

If CO2 is the principal driver, can you explain why the temperature has remained within a 12 degree band for the last 500,000 years? What determines the bounds? 

The most rapid increase in temperature seems to have occurred between 15,000 and 10,000 years ago, with a similar characteristic to the cycle between 135,000 and 125,000 years previously. The shape of the curves suggests a common cause and even if you ascribe the recent one to pre-Stonehenge agriculture, you'd have a problem blaming the early neanderthals for raising the CO2 concentration above today's level.

[Zer0]

There isn't Any doubt that it's Rising.

But Yes, knowing the Exact reason behind it is equally as important as tackling it.

Ps - even humans running around on the surface of the planet must be contributing to heat.
Like excited particles in a hot cuppa coffee.
☕

[Bored chemist]

Why tell that lie?

[alancalverd]

Not a lie, but the rational interpretation of what you did say.

[alancalverd]

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.   

Here's how saturation was described in the 2001 IPCC report (AR3):

"Carbon dioxide absorbs infrared radiation in the middle of its 15 mm [sic] band to the extent that radiation in the middle of this band cannot escape unimpeded: this absorption is saturated.....

but that's just physics, apparently confirmed by every published graph of atmospheric transmittance at 15 μm. Since said graphs all seem to date  back to the 1950s and are politically inconvenient, why can't I find a more recent measurement consistent with the CO2-driver hypothesis?

[Bored chemist]

Not a lie, but the rational interpretation of what you did say.

No, a deliberately irrational interpretation.

So when did the laws of physics change?

When CO2 no longer caused warming.

[alancalverd]

Improbable, and unpopular. Most people think the laws of physics haven't changed since a few milliseconds after the Big Bang.

Anyway, rather than argue the toss, I want to measure the intensity of outgoing 15 μm radiation as a function of altitude at night. Can anyone direct me to a suitable commercially available detector? Most of those advertised seem to cut off at 14 μm! 

[Bored chemist]

Improbable, and unpopular. Most people think the laws of physics haven't changed since a few milliseconds after the Big Bang.

And yet the laws of physics would need to change for the greenhouse effect not to work.
So which is it?
Do you believe in the greenhouse effect or do you think the laws of physics have changed?


Incidentally, on a tangentially related note, do you know how a neon oscillator works?

[alancalverd]

Of course there is a greenhouse effect.

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.

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

Why do I care? Because a lot of effort is being expended on minimising the harmless effect (CO2) without considering the cause. Climate change is going to be hugely damaging to humanity, and pissing into the wind may be good for a few political and pseudoscientific careers but won't make life tolerable for my grandchildren.

The only explanation of climate change that makes sense to me is that water is the driver. This means that it is wholly out of our control, so instead of tilting at the CO2 windmill we need to reform society to become resilient to the inevitable. Politicians do not like reforming society on the scale required for the survival of a decent standard of living.

[alancalverd]

Neon oscillator.

I presume you mean a relaxation oscillator using a neon tube. It is one of those neat circuits that fascinated me as a kid and is still fundamental to a whole bunch of robust devices - including radiation detectors that I use every day.

The circuit consists of a resistor and capacitor in series, with a neon lamp in parallel with the capacitor. If you apply a constant  voltage V to the series elements, the voltage across the capacitor increases asymptotically towards V. At some critical voltage Vi  less than V, the neon gas ionises and effectively short-circuits the capacitor which discharges until the lamp extinguishes at a lower voltage Ve. Thus the voltage across the capacitor becomes a cyclic sawtooth with a slow rise and rapid fall, with a repetition time of about 0.63 RC.

[Petrochemicals]

I cannot find a rational interpretation consistent with CO2 being the driver of historic climate change.

CO₂ is probably NOT a driver of climate change historically until we look way back to time periods FAR predating ice cores (ie last time the atmosphere had significantly more CO₂ there was no ice at the poles...

And unless there was some non-anthropogenic process capable of putting 10¹³ kg of CO₂ into the atmosphere in 150 years (practically instantaneous on geological timescale), there isn't likely another such event in the "historic" climate change

If it was not a driver historically, why should it be now. The greatest current potential driver of co2 is the peatbogs of siberia, methane and co2. If they warmed and dried historically due to temperature change that would release humungous a mounts of CO2, afterwards the temperature crashed into an ice age for some reason.

[Bored chemist]

So you do understand how a positive feedback element (like a neon tube where increased current increases the conductivity leading to a further increase in current and so on) can turn a slowly varying parameter such as the voltage across a capacitor, into a rapidly varying one.

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?

Imagine driving a neon oscillator with a voltage that slowly varies between a bit less than the strike voltage of the neon and a bit more.
Do you see how the brightness of the lamp would vary suddenly?

Now, can you explain why you thought that this was a sensible claim?

So you assert that all the major temperature fluctuations in the last 400,000 years were due to sudden orbital shift