[alancalverd]

I proposed the acid test way back. Use the model to back-cast and match it to ice core data, and see if it explains the regular superimposed ripple on the recent Mauna Loa data. You have produced a good test of the validity of underlying assumptions by comparing their predicted tephigram with reality.

[Petrochemicals]

Immediately after 9/11 there  was an absence of vapor trails over the USA

None of the components I tested was likely to be plated with FeS2

Would you consider changing your name to Naked Science Forum TROLL!, or perhaps Naked Science Forum Red Herring merchant?

I posted this to discuss climate models. Every post you make is designed to derail the thread with pointless red herrings. Please stop acting like a child.

I proposed the acid test way back. Use the model to back-cast and match it to ice core data, and see if it explains the regular superimposed ripple on the recent Mauna Loa data. You have produced a good test of the validity of underlying assumptions by comparing their predicted tephigram with reality.

What is your acid test proposal or hypothesis or question, what are you testing precisely?

I think that the contralis is the 2nd best acid test suggested, volcanic eruptions have too many variables, co2 into the higher atmosphere out but so are screening particles. Co2 in the upper atmosphere is more likely to cool the planet, due to the curvature of the earth having alarger aperture back into space than toward earth.

https://en.m.wikipedia.org/wiki/Contrail

Or we could pump co2 into the atmosphere and acid test that way.

[alancalverd]

The quickest test of (almost) any model is whether, starting from "now", it can generate  an accurate picture of the past. Or whether, starting from a known point in the past, it accurately predicts the status quo.

Given the panic caused by climate change, it's unlikely that anyone will be impressed by a forecast based on "business as usual" that will take some years to validate, but the historic record of the last 400,000 years is sound.   

[Bored chemist]

You can find their equations here at the Open Peer Review Journal - where you can submit your peer review of their article.

OK, so they are just misusing the phrase in an attempt to sound "sciencey".

[Bored chemist]

I posted this to discuss climate models. Every post you make is designed to derail the thread with pointless red herrings. Please stop acting like a child.

It might have been better if you hadn't included a reference to a totally irrelevant bit of historical chemistry.

[alancalverd]

So here's an experimental test of the underlying assumptions of a CO₂-forcing model.

Atmospheric pressure at sea level  is 10,500 kg/sq m. Of this, about 400 ppm is carbon dioxide, i.e. 4.2 kg/m².

Density of CO₂ is about 1.8 kg/m³. So if we add a 2.3 m tall column of CO₂ to the existing atmosphere, the effect at the bottom of the column will be the same as doubling the concentration throughout the entire atmosphere.

Place two large transparent plastic hemispheres of about 3 m radius, on dry sand, in a shadowless environment ( any flat desert). Fill one hemisphere with carbon dioxide, and measure the ground surface temperature of both. The difference is what would be caused by a doubling of the overall CO₂ concentration in the short term. The longterm effect, and specifically in non-desert regions, is not predictable as increased CO₂ produces increased plant growth, with a consequent reduction in atmospheric water. But you might get some indicative data by reproducing the experiment over water or ice.   

[chiralSPO]

The longterm effect, and specifically in non-desert regions, is not predictable as increased CO2 produces increased plant growth, with a consequent reduction in atmospheric water.

Increased plant growth does not simply lead to a reduction in atmospheric water... often plants *increase* water concentrations in the atmosphere through transpiration (https://en.wikipedia.org/wiki/Transpiration). https://e360.yale.edu/features/how-deforestation-affecting-global-water-cycles-climate-change

It also isn't entirely clear that more atmospheric CO₂ will necessarily lead to more plant growth.

[Bored chemist]

Presumably you would get a result a bit like this one.

[Bored chemist]

the effect at the bottom of the column will be the same as doubling the concentration throughout the entire atmosphere.

No, because ... science.

[alancalverd]

It also isn't entirely clear that more atmospheric CO2 will necessarily lead to more plant growth.

There are a lot of tomato growers in the Lea Valley who are wasting their time, then. Not to mention tropical agronomists.

[Petrochemicals]

The longterm effect, and specifically in non-desert regions, is not predictable as increased CO2 produces increased plant growth, with a consequent reduction in atmospheric water.

Increased plant growth does not simply lead to a reduction in atmospheric water... often plants *increase* water concentrations in the atmosphere through transpiration (https://en.wikipedia.org/wiki/Transpiration). https://e360.yale.edu/features/how-deforestation-affecting-global-water-cycles-climate-change

It also isn't entirely clear that more atmospheric CO₂ will necessarily lead to more plant growth.

Water  content (absolute molecular content)is limited by the gaseous laws not addition-subtraction unless there is no moisture in the vecinity. Water will evapourate if the gaseous laws dictate, cooling the medium in the process. Jungles are very hot but due to 100 percent humidity evapouration is lacking .

[chiralSPO]

It also isn't entirely clear that more atmospheric CO2 will necessarily lead to more plant growth.

There are a lot of tomato growers in the Lea Valley who are wasting their time, then. Not to mention tropical agronomists.

I have no doubt that increased CO₂ concentrations help plants grow in otherwise tightly controlled circumstances. However, due to things like... CO₂-driven climate change... it is possible that disruptions in local ecosystems may cause a net drag on biomass accumulation for a while, until the new equilibrium is established, which could take a very long time in civilization timescales, even if it is very brief on a geological timescale.

[chiralSPO]

The longterm effect, and specifically in non-desert regions, is not predictable as increased CO2 produces increased plant growth, with a consequent reduction in atmospheric water.

Increased plant growth does not simply lead to a reduction in atmospheric water... often plants *increase* water concentrations in the atmosphere through transpiration (https://en.wikipedia.org/wiki/Transpiration). https://e360.yale.edu/features/how-deforestation-affecting-global-water-cycles-climate-change

It also isn't entirely clear that more atmospheric CO₂ will necessarily lead to more plant growth.

Water  content (absolute molecular content)is limited by the gaseous laws not addition-subtraction unless there is no moisture in the vecinity. Water will evapourate if the gaseous laws dictate, cooling the medium in the process. Jungles are very hot but due to 100 percent humidity evapouration is lacking .

Yes.

But typically the water content of air is not at equilibrium (if there is liquid water, then at equilibrium, air would be saturated with water... ie 100% humidity).

As you point out, jungles often achieve 100% humidity, while we don't typically observe this over bodies of water (where presumably evaporation would be quite swift).

This is because transpiration causes much faster rates of water evaporation on a per acre basis.

[Petrochemicals]

The longterm effect, and specifically in non-desert regions, is not predictable as increased CO2 produces increased plant growth, with a consequent reduction in atmospheric water.

Increased plant growth does not simply lead to a reduction in atmospheric water... often plants *increase* water concentrations in the atmosphere through transpiration (https://en.wikipedia.org/wiki/Transpiration). https://e360.yale.edu/features/how-deforestation-affecting-global-water-cycles-climate-change

It also isn't entirely clear that more atmospheric CO₂ will necessarily lead to more plant growth.

Water  content (absolute molecular content)is limited by the gaseous laws not addition-subtraction unless there is no moisture in the vecinity. Water will evapourate if the gaseous laws dictate, cooling the medium in the process. Jungles are very hot but due to 100 percent humidity evapouration is lacking .

Yes.

But typically the water content of air is not at equilibrium (if there is liquid water, then at equilibrium, air would be saturated with water... ie 100% humidity).

As you point out, jungles often achieve 100% humidity, while we don't typically observe this over bodies of water (where presumably evaporation would be quite swift).

This is because transpiration causes much faster rates of water evaporation on a per acre basis.

I should say that a jungle provides exellent evapouration mediums, soil absorbs light, air becomes heated,  where as the ocean is transparent to light thus it penetrates the water surface without heating, the wave circulation of the water, the problem of water density suddenly peaking at about 5C all keep the air cool , thus the gaseous laws lower the evapouration rates.  And with evapouration comes cooling which ensures everything stays cool.

[Bored chemist]

It also isn't entirely clear that more atmospheric CO2 will necessarily lead to more plant growth.

There are a lot of tomato growers in the Lea Valley who are wasting their time, then. Not to mention tropical agronomists.

So, you don't understand the word "necessarily" means.

[evan_au]

Can we conduct a climate model "acid test"?

The "acid test" of climate models is happening right now, in our oceans, lakes and rivers.

Increased atmospheric CO₂ results in higher dissolved CO₂  (more of our emissions are dissolved in the oceans than are held in the atmosphere).
- Higher dissolved CO₂ results in more acidic water (lower pH)
- More acidic water means that invertebrates like corals, shellfish, crabs, plankton, etc have to expend more energy to build and maintain their shells - or try to survive with weaker shells
- plankton is the base of the marine food web; undermine the base, and the edifice collapses...

[alancalverd]

https://www.nature.com/articles/d41586-019-00537-8

So, you don't understand the word "necessarily" means.

I generally try to eschew subjective adjectives when discussing matters of science, but 
https://www.nature.com/articles/d41586-019-00537-8
suggests that scientists agree with my statement.

Admittedly, that's only from observation, not prejudice or computer model, and is therefore somewhat unfashionable.

What Evan says is almost certainly true. But it is an effect of rising CO2, not a predictive model of climate change. I do still worry about southern England, however. Vast rolling hills of chalk, all made from the shells of long-dead plankton. Whence came all that carbon dioxide? Not from the friendly, CO2-free pre-industrial atmosphere, surely?

[Bored chemist]

I generally try to eschew subjective adjectives w

Either it is necessarily true or it is not.
That's not subjective.
On the other hand, your use of "subjective" is debatable (at best) which means it's subjective and perhaps you should have eschewed it.

Do you accept that, in an atmosphere of pure CO2 the plants would die  ?

[Bored chemist]

I generally try to eschew subjective adjectives when discussing matters of science, but 
https://www.nature.com/articles/d41586-019-00537-8
suggests that scientists agree with my statement.

And here's what they say on that page
Globally, rising carbon dioxide concentrations also seem to be playing a part, but that part is probably smaller than previously assumed, the scientists say. They add that although greening farmlands are becoming more productive, the gains do not make up for environmental damage resulting from tropical deforestation.

So, the net effect is a reduction of plant growth.

[alancalverd]

I generally try to eschew subjective adjectives w

Either it is necessarily true or it is not.

So the word "necessarily", like "existential", adds nothing to the sentence. 

Do you accept that, in an atmosphere of pure CO2 the plants would die  ?

If it is true, I'll accept it. Is it [citation needed!]?

More to the point, is it relevant? Some people drown, some die of thirst. Animals die in an atmosphere of pure oxygen at 1 bar. Mammalian respiration is impaired in the absence of CO2, or at a 100% concentration. So what?

What we do know, from  observations ranging from laboratories via commercial growers to satellite images of the entire planet, is that more CO2 than the atmospheric concentration of 50 years ago, promotes plant growth. This is consistent with everything we learned about biology at primary school: plants convert carbon dioxide and water into all sorts of useful stuff. 

None of which has anything to do with climate modelling, at least to the first order. It does however suggest that there is a longterm equilibrating mechanism. Consider just fossil fuels: every carbon atom in oil or coal was extracted by plants from the atmosphere, so at some time there must have been more carbon in the sky than there is now, because there is no natural mechanism for returning fossil carbon to the atmosphere. This fact must feature in any valid climate model that treats CO2 as a significant cause or effect.

No question that tropical deforestation is a Bad Thing. So is starvation. But as long as we continue to breed humans that like to eat meat and waste palm oil, it will continue, so it needs to be taken into consideration in a climate model.