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srid  8mo ago (cafeamericainmag.com)   Edited 8mo ago   4182 thread views

The Vacuity of Climate Science

cafeamericainmag.com

There has been a lot of CW discussion on climate change. This is an article written by someone that used to strongly believe in anthropogenic global warming and then looked at all the evidence before arriving at a different conclusion. The articles goes through what they did.

I thought a top-level submission would be more interesting as climate change is such a hot button topic and it would be good to have a top-level spot to discuss it for now. I have informed the author of this submission; they said they will drop by and engage with the comments here!

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I can't comment on most of this, except the following:

This makes it all the more peculiar that nobody has been able to experimentally demonstrate and therefore verify the greenhouse effect.

Wouldn't the existence of Venus be pretty definitive proof that such a thing is possible?

Venus has twice the irradiance, 90 times the atmosphere, no significant phase change cycles, no water to absorb energy, slow diurnal rotation. Just do a comprehensive experiment on Earth, it will do us more good.

This makes it all the more peculiar that nobody has been able to experimentally demonstrate and therefore verify the greenhouse effect.

Experimentally proving the greenhouse effect is a common science class task for sixth graders. The author of this could probably do it with materials that exist in his house. This is a rather extreme self-imposed ignorance.

The ignorance is coming from this reply not from the author of the article. It is salient that you didn’t actually provide a link, source, or explanation of how the GHE can thus be verified. It also doesn’t address why the referenced 2021 peer reviewed paper said a lab verification was lacking — because the typical demonstrations (involving gas in glass jars or plastic bags) don’t demonstrate the GHE. Their results are an effect of gas densities affecting convective heat loss, not radiative effects. They work equally well with Argon.

They work equally well with Argon.

Is it based on experiment or a guess?

On experiments:

  1. "Benchtop Global-Warming Demonstrations Do Not Exemplify the Atmospheric Greenhouse Effect, but Alternatives Are Available", https://pubs.acs.org/doi/10.1021/acs.jchemed.8b01057

    _

    (It must be noted the "alternatives" provided are analogues, not demonstrations of the GHE.)

  2. "Climate change in a shoebox: Right result, wrong physics", https://www.researchgate.net/publication/243492513_Climate_change_in_a_shoebox_Right_result_wrong_physics .

Here is a benchtop experiment. Figure 6 apparently shows that variations in the density of air in a balloon do not affect it's cooling rate, whereas it does for a CO2 filled balloon. This would seem to contradict your claim that it's a spurious density effect.

https://royalsocietypublishing.org/doi/10.1098/rsos.192075

It may be worth reviewing the links I just provided as to why Argon is a valuable control for these experiments (https://www.themotte.org/post/960/the-vacuity-of-climate-science/203988?context=8#context).

In short: carbon dioxide is more dense than air. CO2 and Argon are about the same density as each other. A typical experiment involves adding CO2 to a beaker and observing the surface temperature get hotter. But the reason is that the convective loss of the bottom is suppressed because the air is prevented from rising due to the heavier CO2 above it. This works equally well with Argon. In closed containers, the differing gas density still affects the rate of convective loss, as #2 points out.

The experiment you linked must therefore also be performed with 100% Argon (as it was with 100% CO2) as a control.

I dont see how those are relevant to the study I posted. Those were open systems where mass exchange with the environment is possible, but in the one I posted the gasses are sealed in balloons.

This was the relevant part: "In closed containers, the differing gas density still affects the rate of convective loss, as #2 points out."

Quoting from the paper, emphasis added:

Even if the experiments were done in a sealed container, and CO2 were compared with Ar, differences in convective transport could not be ruled out.

[...]

In some of the reported demonstrations, the container is sealed so that interfacial mixing should not be a factor, but a temperature difference between air and CO2 was still reported.[3–5] Sealing the container brings into play additional factors, which are difficult to quantify, especially the infrared characteristics of the “window.” In Ref. 5, for example, T is reported to be 25% greater for CO2 than for air. As we have argued, a difference of this magnitude cannot be accounted for by far-infrared absorption. This experiment probably involves the direct absorption of sunlight rather than of reemitted far-infrared radiation, but that effect should be even smaller. [7] Simple models of natural convection suggest that the difference in the heat flow between the two gases should be less than 10%.[17] The calculations depend on the geometry, however, and the conditions are in a transition regime between laminar and turbulent flow, and thus it is possible that small changes could have disproportionate effects. These uncertainties reinforce the value of including a comparison case that uses a heavy gas without infrared absorption, such as argon.

The key here is “experimentally demonstrate”. Pointing to Venus isn’t an experiment! I thought the following demonstrated why rather effectively:

“The problem this poses is best exemplified by going back to Pekeris 1932. (It must be noted that Hansen et al 1983 cites Wang 1976 which cites Goody 1964 who then cites Pekeris 1932). In Pekeris, the models of the time led the scientist to believe that “it becomes plausible the temperatures on […] Venus, Earth, and Mars are about the same”. As Venus’s temperature is 464ºC while that of Mars is -63ºC, his egregious error reveals the fundamental problem of not having experimental means by which to validate models. This leads to a situation where models are susceptible to overfitting available data, with no ability to check their operations by proving that the actual effect matches the model’s prediction.”

Sure, it’s an observation, rather than a prediction. That’s fine for a control group, but insufficient. At least it lets us rule other theories out.

So…what would constitute experimental demonstration? What could I do to convince you that the greenhouse effect can, in fact, trap some amount of heat?

For that matter, I don’t see you providing any experiments yourself! Why should I privilege your bench-top reasoning over the IPCC’s?

It’s a good question and is already addressed in the article:

“Although the burden of proof is on a theory’s proponents rather than its critics, we can conjecture what one such proof might look like: it would have to consist of an external energy source – such as the sun or a heat lamp – that is set to warm a surface. The energy input should be measured and the surface, in the presence of greenhouse gases, should get much hotter than that input alone can provide, emitting much more energy in response. This would definitively demonstrate the greenhouse effect itself, after which the anthropogenic influence could be gauged by introducing more carbon dioxide into the apparatus and measuring the marginal temperature response.”

Will wait for author to signup and post, but meanwhile this may be relevant:

https://twitter.com/DaleCloudyman/status/1779113392747249970

https://greenfallacies.blogspot.com/2021/10/greenhouse-gas-effect-is-junk.html?m=1

From your first Twitter link, the guy gets it wrong right off the bat. "How can the GHGE work after so long a night?" Because of the thermal mass of the ground and atmosphere, and the insulating properties of the atmosphere which is much thicker than Earth's, and because high winds on Venus tend to equalize day/night side temps.

This guy doesn't know what he's talking about.

https://twitter.com/_Escapekey_/status/1748317807006118335 is also cute, as growth is also visible before their claimed start of conspiracy (even on their own graph, no idea is any claim there even accurate)

You need to escape the underscores. https://twitter.com/_Escapekey_/status/1748317807006118335

Thanks!

From your second link:

A typical validation of the Stefan-Boltzmann’s law of radiation : is done by measuring the radiation from a filament of the incandescent lamp. The filament is enclosed in a vacuum.

A typical demonstration of radiative heat transfer is done in a vacuum, but that isn't a real requirement. You can instead compare the total heat transfer from a hot black plate (emissivity near 1) to the heat transfer from a hot silver plate (emissivity near 0). The black plate will have faster heat transfer despite being surrounded by the same air because it radiates more.

I'd like to see his calculations for "...the conductive and convective effects at the surface are vastly greater than the radiation; by about 240 times."

Venus has a very high albedo. Most sunlight is actually reflected away from the planet. Venus actually gets less net sunlight than earth! GHGE says Venus, without a greenhouse gas effect, should be cooler than earth!

No!!

Even if you assume the emissivity of the object (such as Venus) can be fully described in a single number (i.e. it is an ideal gray body), you're only describing the gross rate of radiative heat transfer. Any ideal gray body that was protected from conduction/convection would reach the same equilibrium temperature given the same surroundings; a high-emissivity one would absorb a lot of energy which is coming in and emit just as much, while a low-emissivity one would absorb a tiny bit of energy and emit just as little.

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