Tuesday, 2 February 2021

Why the gravito-thermal explanation trumps the 'greenhouse effect'

UPDATE May 2021. I've boiled this all down to a simple explanation based on common sense, basic maths and a rudimentary knowledge of the Gas Laws.

Please read my post Acceleration ≈ Gravity
From Forbes, replying to the question "If Heat Rises, Why Is It So Cold In The Mountains?":

Gas also get cooler as its pressure drops, which it does as it rises up where there is less air pressing down on it. So when warm air rises, it cools off. That’s pretty significant here.

This paragraph over-simplifies to the point of being totally wrong. The effect of reducing density by half and pressure by three-quarters (i.e. at 10 km up) would be to cool some air which has risen from the ground to about negative 100 C (if I understand this correctly). Actually it's a balmy negative 50 C up there.

What actually happens is sunlight hits the ground and warms it up; this warms the air; warmer air is less dense so it rises; energy cannot be created or destroyed, so thermal energy is converted to potential energy. That's how the lapse rate formula is derived, then you adjust it for latent heat of evaporation/condensation = 6.5 degrees per km altitude. You work out temperature first, and (lower) pressure and density are derived from that. Moving on...

But there’s an even more important force at work: Earth radiates heat (infrared light) into space. Down near sea level, heat from the sun hits the ground and is trapped under 100 km (at least) of insulating air and clouds that intercept escaping heat and re-radiate it back toward the ground. The higher up you go, however, the less any of this can happen. Above a certain level, the atmosphere loses heat to space faster than is can be warmed either directly (by sunlight) or indirectly (from the ground) so it gets colder and colder.

Up to a point.

Air, being mainly NO2 and O2 doesn't emit much radiation. Neither does CO2, for that matter, it just absorbs 5.14% of infra red and warms up slightly and then warms up the 2,499 other molecules around it (see footnote). The first assumption must that the atmosphere would warm to the same temperature as the surface. If you assume no atmosphere (like on the Moon), you can calculate the likely temperature of the surface quite easily and accurately, based purely on incoming sunlight = effective temperature +/- adjustments.

So our first assumption is that earth's atmosphere would be 255K (the effective temperature of Earth's surface based on incoming sunlight alone). And its average temperature is indeed about 255K, but then you have to adjust for the lapse rate, so it's 33 degrees warmer at the surface - and 33 degrees colder at the top of the troposphere, approx. 10 km up.

The final sentence ("Up to a point") is a nod to the fact that the greenhouse effect does NOT explain why it is so cold on very high mountains. If you look at the temperatures at the top of mountains which halfway up the troposphere (5km to 6km height), the temperature is what you'd expect based on incoming sunlight alone, you can cheerfully ignore all the air above it, of which there is still a heck of a lot (nearly half by mass). If the greenhouse effect existed, it would be warmer than that. No evidence of greenhouse effect.

But let's climb further, to the top of Mount Everest, near the top of the troposphere. Its effective and actual temperature would also be 255K (assuming no atmosphere) but its actual temperature is a darn sight colder than that. According to the greenhouse 'trapping' effect, its temperature would be at least 255K, plus a smidge for the greenhouse effect of the small amount of air above it (about 25% by mass). In actual fact, there appears to be a negative greenhouse effect. Which can't exist, by definition.
Footnote - first the article says radiation energy is 'trapped' (plausible) and then they say it is re-radiated. Which one is it? It can't be both.

The Alarmists like to do demonstrations where they fill a tube with CO2, place a heat source at one end and measure the amount of radiation that gets through to the other end - it's very little, which indicates 'trapping'. If it were re-radiating, then at least half would get through. So 'trapping' seems more plausible and CO2 absorbs 5.14% of the radiation from the surface and warms up a smidge, that warms up the air around it by 1/2,500 of a smidge, which is a small number, certainly less than one degree. And the gravito-thermal effect greatly outweighs this at the top of Mount Everest.

Then there's this: "Above a certain level, the atmosphere loses heat to space faster than is can be warmed either directly (by sunlight) or indirectly (from the ground) so it gets colder and colder."

Nope. The atmosphere doesn't lose thermal energy to space (and it can't lose it faster than it receives it). The only way it could cool down is to emit radiation, which it doesn't (to any great extent). The point is, the air up there was never that warm in the first place - see explanation of lapse rate.


Penseivat said...

Slightly off topic, but in the current political climate, especially in the Colonies across the Atlantic, are you allowed to use the word "trumps" in the definition of "it beats" or "it is preferential to"? We all know he won, but Biden or Harris supporters may now be allowed out of their care homes to throw stones through your Windows.

James Higham said...

Gravito-thermal eh? Have to remember that one.

Dinero said...

You can have trapped and re-radiated together. What is meant by that is IR that was going in one direction is absorbed by the gas , becomes heat vibration of the gas and that gas that is now hot, emits IR back towards where it came from.

Mark Wadsworth said...

PS, Trump lost. As Leavers say to Remainers, "Get over it".

JH, it's not a very catchy name, but there isn't a widely used one.

Din, sure you can, but that's not what the demonstrations show. They show that radiation is absorbed and not re-emitted. And in the article, he flips back and forth between two possible explanations.

I'm genuinely trying to find out what the Alarmists actually mean, I wish they would make up their minds.

Dinero said...

In the video the image of the candle disappears because the Co2 absorbs the IR. I fully expect it is re- emitting the IR in all directions and so there is no longer an image.
A more applicable demonstration would be the length of time it takes for an ice cube to melt on a black slate in a zip lock bag in the sun when the bag contains co2. Can not say I have tried it myself.

Mark Wadsworth said...

Din, that's my problem. Energy cannot be created or destroyed.

If CO2 warms up, then the radiation energy has been converted to thermal energy.

If CO2 re-emits the radiation, then it would stay the same temperature.

As to the zip lock and similar experiments, they do NOT demonstrate what they claim to.

We are told that sunlight is at wavelengths which do not affect CO2, so sunlight hits the ground. Almost certainly true.

The claim is that CO2 either absorbs or re-emits (not sure which) IR coming up from the ground. So a better experiment is have a box of CO2 and a box of normal air just standing on the ground when the sun isn't shining. Including all night long.

Then see if the CO2 box gets warmer, and if so, adjust for the fact that CO2 has lower specific heat capacity and lower thermal conductivity (insulates better than air).

You will find that you don't need to invoke the bogeyman 'radiation' to explain any differences in temperature and rate of cooling.

mombers said...

I double checked the Common Ground (YPP v2) manifesto and thank goodness it doesn't mention any policies to reverse on the basis of this analysis. Not that anything would change - fossil fuels are an increasingly expensive energy source compared to renewables, even before putting a cost on 100% undisputed externalities

Mark Wadsworth said...

M. My view is as follows:

1. As a matter of general Georgist principles, there should be taxes on the value of stuff that you extract from the ground, which of course includes taxes on fossil fuel.

2. There are other good environmental or political reasons to reduce reliance on fossil fuels. Cost is not one of them (yet, when it is, we'll stop using them anyway).

3. CO2 levels have absolutely zero effect on climate. I used to accept this as true, but the more I look into it, the more I realise it is a load of nonsense. It's contradictions within contradictions and lies within lies and alternative explanations and 'models'.

mombers said...

@MW 3 "CO2 has absolutely zero effect on climate"

That's huge news! Do let me know when you get a peer reviewed paper out. The embarrassment of the scientific community will be huge. How could they have missed this?

Mark Wadsworth said...

M, if it did, why don't they explain how and why instead of constantly putting out highly misleading and contradictory claims?

Plenty of actual weather and radiation experts have explained why it can't and pointed out the more plausible reasons for recent modest temperature changes. They have all lost their jobs or been sidelined.

Bayard said...

mombers, the (climate) scientific community don't do embarrassment, they have faith. They know they are right.

Bayard said...

Also on the subject of peer review: who are a climate scientist's peers? Other climate scientists, who believe the same things as the authors of the papers. This is not objective criticism.

mombers said...

@B if you had a magic wand and were proved right, what would you change about current public policy?

Mark Wadsworth said...

B, exactly.

M, the first and most important thing to do is to look much more closely at the impact of CFCs and ozone depletion on temperatures and try and discourage China from making CFCs.

Then do a proper control experiment re CO2 (see today's post) to debunk the whole AGW thing.

As it happens, taxes on fuels extracted from the ground should be more heavily taxed under general Georgist principles (and other taxes reduced). Moving towards renewables if they are cheaper and/or provide better energy security (plus getting one over the Saudis) is clearly a good idea; as is improving public transport in cities to make car use redundant.

Finally and just as importantly, stop panicking and terrorising people with tales of imminent catastrophe!! That is not helping anything and serves no useful purpose.

mombers said...

@MW so no change in policy (Addressing CFCs and climate change are not mutually exclusive). Although I think you did mention keeping coal power stations going?

You will need to find a small army of scientists to replace the thousands who, in your opinion, have all got it wrong. The fossil fuel industry spent a lot of money trying that over the years, not sure where you would be able to find more resources than they threw at it.

I hope you can see why I'm confused about the amount of (renewable :-)) energy that you and others devote to this

Mark Wadsworth said...

M, I have no strong opinions on coal, solar or anything else.

I am heartily sick and tired of all the "climate crisis" hysteria, it is completely counter-productive. That's why I put so much effort in, I hate being lied to, by journalists, activists and 'climate scientists'.

The fossil fuel people weren't really trying. And any research or experiment they paid for would be tainted by association, people would rightly be suspicious.

mombers said...

@MW under Georgist and Pigouvian principles, coal and internal combustion engines impose much too high an externality on people to even calculate what an appropriate rent would be per ton/barrel. What price to attach to a shorter, less healthy life? Natural gas emits fewer toxins but still negatively impacts human health, and Putin and the medieval Middle East are not our mates. We should therefore move off these for non climate change reasons. Then your argument becomes academic I think?

Mark Wadsworth said...

M "What price attached to shorter, less healthy life"?

That is a judgement call.

Even if we replaced all vehicles with the cleanest, non-polluting CO2 neutral modes of transport, there will still be 2,000 deaths and many more injuries on the roads.

Whatever humans do, there is always a risk of death or injury somewhere along the line.

Sit at home and watch telly? Heart attack and obesity due to laziness. people get electric shocks changing plugs. Some engineer falls off a TV mast and dies. Films and programmes have to be made, special effects can be dangerous, travel programmes involve flying somewhere, rugby players get injured, sometimes spectators get killed in stampedes etc.

Eat beef? More people (farm workers and dog walkers) are killed by cattle than by any other animal.

Like I said, I agree that there are non-climate reasons for doing what you recommend, which we can discuss calmly and rationally.

I am just sick and tired of the lies and propaganda and pseudo-science quasi-religious bollocks.

Mark Wadsworth said...

... also, I have never complained about or campaigned against renewable energy or anti-pollution measures. You are jumping to that conclusion on the basis of no evidence.

Michael Miler said...
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