Can the atmosphere really warm? Atmospheric gas retention.

[Weatherman]

The temperature stays steady or warms with height in the stratosphere. Because, unlike the troposphere, which is warmed from the bottom by the earth's surface, the stratosphere is warmed from the top by the ozone layer.

With few exceptions, the coldest location in the lower part of the atmosphere is right where the troposphere and stratosphere meet (the tropopause). It's the location farthest away from the two heat sources.


Unless heat is added or removed from an air parcel, the temperature will decrease with height due to the decrease in pressure. This is called the adiabatic lapse rate (dry adiabatic is about 5.5F/1000 ft). In a perfectly mixed and perfectly dry atmosphere, with no radiative, convective, conductive or advective heat loss or gain, the air temperature will decrease with height at the dry adiabatic lapse rate all the way from the bottom to the top.

 

[AndyH]

Thanks for the explanation, but I'm struggling with these graphs - if I understand you, you're suggesting that where the temperature hits a point where it doesn't change with vertical height that this is a 'lid'.

Surely, if there was no vertical movement then the atmosphere would get colder with altitude? I would have thought a steady drop in temperature with height indicates a lack of vertical mixing, while a steady temperature would indicate vertical transport in that region, no? What am I missing?

Indication of a steady temperature with increase in height might be considered to demonstrate vertical mixing, rather than being 'capped', because that way the layers will mix and attain the same temperature? Why would upper layers be the same temperature as a point below the 'lid'?

I'm glad you looked at the links Weatherman provided. I gave you this information earlier but you didn't appear to open them or read the explanations provided earlier.

Yes, in general terms the atmosphere can be roughly broken into three sections - a lower part with convection and mixing, a separator layer, and the upper atmosphere. The lower, warmer section follows a fairly linear lapse rate - getting about 1°C colder for each 100 meter rise. The other two layers don't behave the same way. What you're missing is the basics of how the atmosphere works. I've given you additional background here and in the other thread that addresses how we know about the 'separator' layer functions.

This was available to you on page 2 - it provides background on what Weatherman's telling you.
http://farside.ph.utexas.edu/teaching/sm1/lectures/node56.html
http://www.iges.org/straus/CLIM_710/Radiation_Climate.pdf

 

[Nubo]

You're mixing issues there. Happy to explain it to you: One phrase says 'I don't understand the issues' the other says 'I conclude the documents I've seen don't consider the issues I'm interested in'

No, your statement was not qualified as "documents I've seen". It was an absolute.

So my conclusion is that the expansion of the atmosphere is not taken into consideration in climate models. That gets added to the list of other apparently disregarded matters in these models; the role of clouds, water vapour, and biological sinks.

 

[donald]

No, your statement was not qualified as "documents I've seen".

That was an illustration, which I felt others understood. Sorry I did not clarify sufficiently for your comprehension.

In this context it was not documents as much as the links, or to be specific lack thereof, I've been offered. I asked folks who I've been lead to believe have read this stuff in much more detail than me to see how atmospheric volumetric changes are taken into account. Nothing demonstrated they were, so the conclusion I gave thus followed.

I think you're arguing for the sake of it. Why not turn your argumentative talents to the technical matters if you have a contribution?

 

[donald]

This was available to you on page 2 - it provides background on what Weatherman's telling you.

I've looked at page 2 of both of those links and regret that I can't see how either explains why/how the temperature above (or 'within') an atmospheric 'lid' is the same as that below/at the bottom it.

I'd still imagine that a vertical region of similar temperature should mean vertical movement there, causing thermal mixing, rather than a 'lid' which conjures images of a static region.

 

[Weatherman]

Think of it this way...

I'm an air parcel, sitting at the tropopause. It's cold. My temperature is -70C. A wave comes along a bumps me up into the stratosphere. What will happen to me?

Well, first I'll experience lower pressures and expand so my temperature will fall (at the dry adiabatic lapse rate). So, suddenly, I find myself colder and denser than my surrounding environment (there's no temperature change with height in the lower stratosphere). What happens to air parcels which are colder and denser than their surroundings? They fall.

So, I fall back down to the tropopause, pressure rises, I contract and heat up and I'm back in equilibrium with my environment.


That's how the stratosphere acts as a lid.

How about a neat time lapse, as a demonstration:

http://www.youtube.com/watch?v=YMyagAJJ0_Y" onclick="window.open(this.href);return false;


Notice how the thunderstorm is trying to blast up into the stratosphere and just gets pushed back down. That's the stratospheric "lid" at work.

 

[klapauzius]

Wow, I think we have diverged quite a bit from the original question.

I have the feeling though, that this isn't all about information, but again about someone sophisticated enough to understand the 11-year old stuff, but not quite sophisticated enough to grasp the full complexity of atmospheric science, yet still feeling entitled to skepticism?

I think the original question was answered on 11 year old level (assuming that 11 - year old's can understand the difference between equilibrium states and dynamic systems).

At least some basic understanding is there, which is more than the other millions in this country, that also feel entitled to skepticism, have...

 

[WetEV]

The logical corollary being is that the equilibrium temperature of a planet is a function of the mass of the atmosphere and the strength of the gravitational field.

If this was true, then how has the planet had large past variations in climate? There is no evidence of large past atmospheric mass changes, or of past gravitational field changes.

At the peak of last glacial advance, the climate was roughly 4C +-1C colder than today. How did this happen?

At the peak of the Paleocene–Eocene Thermal Maximum, temperatures quickly rose about 6C from the already warmer than todays climate of the Paleocene? How did this happen?

And even more extreme, the Neoproterozoic "Snowball Earth" events, with world wide glacial deposits, including land that seems to be have been near the equator, capped with carbonates, deposited at ~40C? How did these events happen?

Variations in greenhouse gases (water, CO2 and CH4) explain these events. Some of these are fairly well documented and were predicted long before the greenhouse gas levels were measured. For example in 1896, Arrhenius calculated that about 0.62 to 0.55 of the present value (which was about 290ppm in 1900) or 160 ppm to 180 ppm of CO2 would cause a climate similar to the peak glacial advance, which he stated was about 4C to 5C cooler.

http://www.globalwarmingart.com/images/1/18/Arrhenius.pdf" onclick="window.open(this.href);return false;

Actual value was about 180ppm.

Arrhenius was a bit high in estimation of the effect of CO2, relative to modern understanding, but missed the effects of lower methane levels and higher dust levels. (yes, I should find a graph with methane levels as well.)

 

[AndyH]

This was available to you on page 2 - it provides background on what Weatherman's telling you.

I've looked at page 2 of both of those links and regret that I can't see how either explains why/how the temperature above (or 'within') an atmospheric 'lid' is the same as that below/at the bottom it.

The information was linked in page two of this thread. The first doc linked doesn't HAVE a page 2. The 2nd is made up of PowerPoint slides all of which are relevant.

 

[WetEV]

I usually don't post videos. This one is worth watching.
[youtube]http://www.youtube.com/watch?v=cBdxDFpDp_k[/youtube]

 

[AndyH]

Fantastic video, Wet - thanks for that. I'm looking forward to watching this full episode.


Donald - I stumbled on this video set from the US National Academy of Sciences. It gives a very nice overview of climate change in seven short videos. Some of the animations make it easy to see the way greenhouse gasses work and how the sun and natural cycles fit into the process. Enjoy.
https://www.youtube.com/playlist?li...W8&feature=iv&annotation_id=annotation_394730

 

[donald]

I'll get back to you when I have 'inwardly digested' more. Obviously I know what the basic argument is meant to be for 'AGW' (but it is still NOT like a greenhouse, sorry, it just isn't), but the key is clearly to understand the 'leverage' on the water vapour content that the CO2 wields, because the CO2 on its own makes very little relative contribution to the overwhelming effect of water vapour and condensate on IR blocking and albedo.

I know enough to say the idea of AGW sounds like bullshit, I just don't know enough to say if it is.

 

[WetEV]

I know enough to say the idea of AGW sounds like bullshit, I just don't know enough to say if it is.

Here is something to think about, some basic physics:

What temperature will a satellite in orbit around the Sun at the same distance to Earth be at?

Assume that the entire satellite is at the same temperature.

 

[donald]

Not sure what you are getting at.

There is absolutely no doubt that the earth is warmer because of the so-called 'green house effect'. I'm not aware of any dissenters on that point whatsoever, and certainly I am not. The problem is that this is dominantly from water vapour, and the interaction (with CO2) and variability of the water vapour contribution is very complex.

I do not argue AGW sounds like bullshit on ground of physics. A purely physics argument sounds quite plausible to me. I say it sounds like that because of geological history.

 

[AndyH]

The problem is that this is dominantly from water vapour, and the interaction (with CO2) and variability of the water vapour contribution is very complex.

Atmospheric science recognizes all of the interconnected factors - I've not seen any scientific paper suggest that planetary warming is due to any single one. The really important piece for you to remember is that we have a number of different GHGs, changes in some affect others, and we have been changing some very dramatically.

Water vapor, carbon dioxide, methane, nitrous oxide, ozone, chlorofluorocarbons (CFC) are the main GHGs. Water vapor clears from the system is less than a week. The others stay in the atmosphere much, much longer and we are increasing the levels of ALL of them, not just CO2. Just look at one - natural gas. Methane is a significantly stronger GHG than CO2 until it degrades...into CO2. Each time the volume of any of these GHGs increases, the lower atmosphere warms more, and more water vapor is held - and that means the atmosphere warms more.

Not sure if electricity or electronics is your thing, but just in case... Think about a relay - a very small amount of energy closes a switch capable of passing a much larger flow of energy. Or a transistor - a small flow of electricity through part of the device allows a much larger flow of energy through the rest. An increase in any of the non-water GHGs triggers warming that 'forces' the atmosphere to hold more water. Heating of the air, ground, and water is a real problem, but the disruption in the planetary water cycle is even larger.

Once you grasp the overall basics, you'll see that there is no disconnect between physics and geological history. The problem we have today is that it's OUR hands on the thermostat, and we've cranked it up much, much higher and much, much faster than anytime in the 1,000,000 of records we have.

 

[WetEV]

A purely physics argument sounds quite plausible to me. I say it sounds like that because of geological history.

Oh? Then how do you explain how climate has been so very different in the past? Greenhouse gas variations do explain this, so what is your alternative theory?

This is a long standing question, once it was determined that most of northern Europe was covered by ice in the past, and that fossils of palm trees, and later turtle, alligators and similar very warm adapted life were found in Greenland.

 

[donald]

Once you grasp the overall basics, you'll see that there is no disconnect between physics and geological history.

hmm .. well, I have seen models that show all hell would break lose on earth if we went to 2000ppm, yet geological history showed that not only did the planet survive but it was a time of significant evolution, and temperature and CO2 levels dropped. Not sure what the 'physics' says about that.

But I do 'get it'. I can see that in a physics model there would be several complex interactions. I just wonder if they are too complex to get an accurate answer, but I do not know enough to comment.

Oh? Then how do you explain how climate has been so very different in the past? Greenhouse gas variations do explain this, so what is your alternative theory?

Are you asking how I explain climate changes during ice ages like the one we are in, or in much warmer periods without perennial ice caps? I've no idea about the latter and how we go in and out of ice ages, but I would imagine the two biggest factors are orbital issues and oceanic currents.

The former - why we get wild weather in ice ages like now - is simple to explain. The albedo of the ice caps produces a fundamentally unstable system. As the ice melts less spectral energy is reflected and the world warms thus accelerating the melt, and as the ice advances more spectral energy gets reflected and the planet cools. Having perennial ice is a fundamentally unstable system and perennial ice is always advancing or receding. We're in a receding 'interglacial' phase at the moment. Interglacials are geologically evidenced as having very unstable weather. There are probably more factors on top of the albedo alone, perhaps cloud formation in respect of more condensate closer to the equator as the glaciers advance, but one way or other albedo is pretty dominant AFAIK, and so essentially there are no stable states for the climate when there is perennial ice at the poles.

If you are going to ask me whether I think anthropogenic contributions to the atmosphere significantly add to this instability, I don't know.

I would tend to doubt anyone can really characterise the stochastic nature of an unstable climate system and then show it is 'more' stochastic as a result of some factor, like anthropogenic contributions to the atmosphere. All I know is that there is no surprise climate is not stable at the moment but I'm willing to be persuaded that something more is going on than just 'ordinary' climate change.

The thing that immediately activates my bullshit detectors is whenever I see anything that alludes to the notion that the climate would be stable if only it wasn't for those darned human CO2 emissions. This is truly false at every level, but if I see an argument saying that climate change is being influenced (rather that 'caused') by CO2 emissions I'm quite willing to take a look at the detail of that argument.

 

[klapauzius]

The thing that immediately activates my bullshit detectors is whenever I see anything that alludes to the notion that the climate would be stable if only it wasn't for those darned human CO2 emissions. This is truly false at every level, but if I see an argument saying that climate change is being influenced (rather that 'caused') by CO2 emissions I'm quite willing to take a look at the detail of that argument.

That seems like semantics. Can there be "non-causal" influence?

Why is it "truly false at every level" that human CO2 emissions drive the current change in climate? Could you provide some succinct arguments with established data for this?

On the other side you have:
1) unprecedented rise in CO2 concentration since the beginning of the industrial revolution
2) a marked departure from the global temperature mean
3) a demonstrated mechanism how increase of CO2 concentration leads to warming, i.e. the "green house effect"

It would be a truly remarkable coincidence if the human caused increase of CO2 in the atmosphere had nothing to do with the increase in global temperature.

 

[WetEV]

hmm .. well, I have seen models that show all hell would break lose on earth if we went to 2000ppm, yet geological history showed that not only did the planet survive but it was a time of significant evolution, and temperature and CO2 levels dropped. Not sure what the 'physics' says about that.

The main sequence of stars. The Sun is big ball of hydrogen, gradually turning into a big ball of helium. As the hydrogen is gradually converted to helium, the star gets hotter. CO2 level at 2000ppm.. When? Today would be a different answer than 4 billion years ago. 4 billion yeas ago, to get liquid water on the surface the total of CO2 would be on the order of 100,000 ppm, or 10% of the atmosphere.

http://climatemodels.uchicago.edu/geocarb/" onclick="window.open(this.href);return false;


As the Sun gets hotter over millions of years, the CO2 level needs to drop to maintain a liquid water surface with only traces of water vapor in the atmosphere. This happens due to carbonate/silicate chemical reactions, aka the weathering of rocks in balance with volcanic release of CO2. Above a certain brightness, the atmosphere becomes about 1bar of just water vapor, CO2 level goes to near zero, and hydrogen loss into space becomes rapid. Once most the water is lost, then the weathering of rocks stops, CO2 level builds to massive, and we get to a Venus-like climate...About a billion years from now.

 

[donald]

As the Sun gets hotter over millions of years....

Maybe so, but the 'physics' model does not describe periods where CO2 dropped while temperatures rose, and vice versa.