"How does solar radiation affect ice covered ocean?"

You have yet to establish that such a complete coverage on the Earth is possible in the first place.

If it did happen then raised insolation (for whatever reason) at the equator would start to melt the ice surfaces more than they would refreeze at night with an exponential effect. You do not need to invoke CO2 or volcanic activity but once present they would add to the effect.

Once you have an ice/slushball you have to establish whether it can escape just by normal variations in solar output. Is there any evidence to suggest that it can? Of course we've got evidence that GHGs could maybe kick start it (despite all the uncertainties), so is there anything else to put on the table?

Stephen

I am not a scientist but I am capable of reading and learning.  I don't engage you in debate in your technical interpretations because it is not my field of expertise, but I will highlight inconsistencies or errors when I see them.

You and I fall out because I don't like the underlying tone of some of your posts.  Your stance that AGW is just insignificant and can be ignored is so far away from everything I read about climate change that my presumption about everything you say is that it is rooted in your, IMHO unreasonable, disbelief.

A good start would be a little more respect for the many climate scientists and their work and conclusions. I accept that everyone is entitled to their opinions but rubbishing and being disrespectful of those who have devoted their labours to understanding the climate stystem is never going to gain my respect or tolerance...

Maybe I have misinterpreted you? 

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If you start with open ocean, away from the polar regions, and progressively the open water freezes all the way to the tropics and possibly beyond, then clearly your mechanism is being overwhelmed by other forcings. If so, the mere fact that there is a small proportion of open ocean is not sufficient to reverse the process.  Some other compensating forcings must be at work.  My understanding of the Snowball Earth theory is that steadily increasing levels of CO2 are the primary driver. If the oceans are mainly ice covered then they are not able to act as a CO2 sink, which puts a progressively larger amount of CO2 into the atmosphere over time.  Of course there will be other forcings, perhaps relating to the Earth's orbit etc.

Your statement doesn't make sense for this reason.  

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"then clearly your mechanism is being overwhelmed by other forcings"

Why so? All that is necessary is for the amount of energy entering the oceans to become reduced for whatever reason. Why need falling CO2 levels be the cause as opposed to orbital changes, solar variability altering the jets, volcanic aerosols etc .

Yet not all are convinced it ever happened.




"Maybe I have misinterpreted you?"

Yes. You are oversensitive on behalf of climate professionals.

"Once you have an ice/slushball you have to establish whether it can escape just by normal variations in solar output. Is there any evidence to suggest that it can?"

Have you established that it cannot ?

And what do you mean by 'normal'. It has happened so rarely if at all that it is way beyond the realms of 'normal' in every respect.

There's a lot of reversing the burden of proof going on these days.

Yes, perhaps - but you are obstinately and relentlessly under-sensitive Stephen.

Challenge is one thing, rudeness and disrespect quite another - as you are fond of pointing out to me. 

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Hang on, you claim that the sun could end a global glaciation, but the burden of proof is on me? Your hypothesis, your burden of proof. Have at it.

To get you started, I mean 'normal' in terms of what we know about orbital cycles and changes in the sun's output.

The sun is the source of all energy in the system.

The starting point is that whatever happens is a consequence of more energy or less energy entering the system.

If you propose that the Earth cannot become a snowball without reducing CO2 or recover without increasing CO2 then that is your hypothesis.

While we are about it how sure are we that it did ever happen ?

We are moderately sure that 'slushball' conditions happened with evidence of cyclical glacial deposits in places that would have been at low latitude at the time. The evidence for a complete snowball is patchy at best.

I never said the Earth cannot become a snowball without reducing CO2. Where did I say that? Reduced levels of GHGs would help for sure but the initial trigger is more likely to be continental configuration (most continents near the equator), changes in ocean circulation, orbital cycles and a slight tendancy towards glaciation anyway as the sun was dimmer 600 million years ago.

I would certainly not say that only large concentrations of greenhouse gases are needed. To simplify, let's say you need 100 units of forcing to get out of a slushball state. Your GHGs have built up to 75 units (arbitrary number) but can't really get any higher. You need to wait for other conditions, solar output, orbit etc to be more favourable and provide the extra 25 units. As soon as it starts melting you probably get a dump of methane into the atmosphere providing an additional kick.

That's how I see it anyway. I wonder if anyone will attempt to run this on a modern model with all their chemistry and biosphere components.

 

BTW Stephen, did you answer my original question that led to this discussion? I asked "Are you saying that if we had the oceans but not GHGs the Earth would be about as warm as it is now?"

Just to clarify, this means imagine that water vapour and clouds have no radiative effects either. Essentially dealing with the approximation that leads to the conclusion that the greenhouse effect adds up to about 33C.

"Are you saying that if we had the oceans but not GHGs the Earth would be about as warm as it is now?"

What do you mean by 'about'?. One has to add the thermal effects of GHGs to the energy storage capability of the oceans. What I am saying is that on the face of it the energy storage capacity of the oceans is far far greater than the energy storage capacity of the non condensing GHGs

I can't see that removing just the non condensing GHGs would prevent a water cycle because solar shortwave would still get into the oceans and the oceans in turn would warm the other gases.

So the issue is just how much of that 33C would still be present in the absence of the non condensing GHGs ?

Some are suggesting that the entire planet would freeze up and die but that seems unlikely as long as solar energy is enough to raise the surface above freezing point and that would happen without any GHGs from direct solar impact on surface molecules.

In theory the surface temperature might even get higher because the lack of GHGs would make the atmosphere more transparent. As well as holding onto energy they also block it from reaching the surface and radiate half the incoming upward again.

So at the level of individual GHG molecules the thermal characteristics are clear but how that translates into a global energy budget effect is still wide open.

Wow. Stephen I think this post displays quite a big misunderstanding of what greenhouse gases actually do. I'm off out now and maybe when I get back someone else will have written a point by point rebuttal of where exactly your thinking is not in line with what we know. If not, I'll do it.

To kick things off though, greenhouse theory does not rely on the energy storage capacity of GHGs, and GHGs definitely increase the amount of radiation reaching the surface. There's zero chance of them reducing the amount of radiation reaching the surface. But I'll provide references for those statements later.

Not so.  The Earth is a ball of molten rock - so there is internal energy as well.   Even under a full snowball, this alone would have ensured liquid water remained (under the ice) and allowed for life to exist.  And a big upsurge in volcanic activity might even be enough to cause more widespread melting? 

Again, not so.  If you heat a room and then open a window, the room cools even though the amount of energy entering the system remains constant. 

If solar output remains constant but you remove - or diminish - the greenhouse effect then the Earth cools.

And since there is no evidence to suggest the sun is an erratic variable star we must suppose that solar activity remained (relatively) constant.

I propose that variations in CO2 may well explain how and why Earth became a snowball/slushball - but accept other explanations may also be forthcoming.   The same variations can also help explain why such periods ended.  The fact they have not reoccurred suggests to me that CO2 levels have since remained at or above a level where the full greenhouse effect has been maintained.

There is plenty of geological evidence for widespread glaciation - whether a complete snowball occurred is another matter (a 'slushball' currently looks more likely).

Regardless, the hypothesis stands as a valid scenario that could have occurred, even if in actuality it did not.

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"Wow. Stephen I think this post displays quite a big misunderstanding of what greenhouse gases actually do."

I included a couple of points I saw from a 'scientist' yesterday and am interested to hear the response. I do that quite often so not everything I post is necessarily my opinion or precise understanding.

One of the biggest problems I am finding is the divergence of opinion and information from 'scientists'. I think Joe Public is having just the same problem.

"there is internal energy as well"

Agreed but I left it out for present purposes because it is so small (except for volcanic outbreaks).


"the room cools even though the amount of energy entering the system remains constant."

Nevertheless the starting point is energy coming in. What happens after that is the whole point.The amount of energy entering the oceans ( I should perhaps have said oceans not system) need not be directly linked to solar TSI. We are seeing that global cloudiness and albedo responds to changes in the composition of solar output and not just total power output.

Well how are we supposed to know what you're talking about? If you don't clarify what in your posts is your understanding and what is another person's idea that you don't necessarily agree with, it will just lead to confusion. Probably better not to do it.

So which scientist made the comment that the heat capacity of CO2 has something to do with its ability to affect the climate? And which scientist made the comment that greenhouse gases could reduce the amount of energy reaching the surface? Have you got links?

Can't trace it, sorry.

Could you explain why the heat capacity of CO2 is not relevant (surely the more energy a molecule holds the more it will radiate?). It might be a semantic issue. The proper comparison might be to compare the length of delay in energy transmission caused by the greenhouse effect in the air with the length of delay in energy transmission caused by energy storage in the oceans

As regards the other point I suspect that CO2 lets energy in but presents more of an obstacle to energy going out but please confirm or clarify.

Well once a CO2 molecule absorbs some energy it doesn't get to keep it for very long. If it were left alone it would re-radiate the energy as a photon in a timescale of microseconds, i.e. 1x10^-6s (on average; it follows a time constant like radioactive decay, so some would re-radiate much sooner than others).

But in a gas at sea level pressure a molecule has something like 1x10^10 collisions per second. This varies linearly with pressure so at 10hPa in the stratosphere it would be 1x10^8 collisions per second.

Clearly most of the time a CO2 molecule will absorb a photon and before it can re-emit, it gets bumped into by another molecule and loses or gains some energy, depending on the properties of the collision. The CO2 can't emit anything now, due to the quantum nature of all this it can only emit when it has certain energy levels (hence absorption and emission lines). The CO2 molecule will emit at some point in the future when it a) absorbs a photon with the right energy and doesn't immediately have a collision, or b) gains the right amount of energy from a collision.

So it's not about how much energy CO2 can 'store'. Its that CO2 and other GHGs have the capability of absorbing IR photons and then transferring the energy to the surrounding molecules. Of course the crucial point is that they also emit photons in random directions so that more IR reaches the surface than it would otherwise do.

Correct, CO2 and most other GHGs do almost nothing to incoming solar radiation and are active in terrestrial radiation wavelengths.

OK, I think I remember seeing that before so thanks for the refresher.

The correct way to look at it then is not as a matter of storage capacity but as a matter of how much of a delay is added between solar energy entering and solar energy leaving the system.

On that basis the oceans would have a far far greater delaying effect would they not ?

For GHGs maybe microseconds. For the oceans including the thermohaline circulation maybe 1000 years or more.

Now both would affect the climate system by changing energy flows and in practical day to day terms that involves changing the air circulation distribution so far as the atmosphere is concerned.

How big or small a differential would you suggest between the effects of human GHGs on the air circulation (microsecond delays) the effects of the oceans on the air circulation (1000 years or more) and the now pretty clear effects of solar variability (operating via albedo and oceanic processes on all timescales) on the air circulation ?

Given that the air circulation systems primarily shift latitudinally to achieve energy budget adjustments in response to such forcings can you express the answer in latitudinal distances ?

To give you a clue the solar and oceanic forcings appear to push and pull those latitudinal positions by 1000 miles or more between periods such as MWP. LIA and current warm period.

Interestingly enough Stephen, I was hunting for references to CO2 cooling the atmosphere and came across Hans Schreuder. Is he who you heard this tidbit from? 

Anyway searching for info on him led me to a post at the Blackboard where Lucia is heavily criticising a book that Schruder co-authored (and my word is that book a mess. Judith Curry also lol'ed at how bad it is).

Anyway, in the comments I came across something relevant to your latest post about how long energy remains in the system, kicked off by some questions by Bill Illis. These were answered by commenter 'SteveF' who I happen to agree with. Here's his comment (comment #67723):

I think that about sums it up.

I don't think that tracking the effect of individual photons (or not) tells us anything about the real world consequences of differential energy residence times in different parts of the Earth system.

Clearly energy residence times are significant in terms of the ultimate real world outcomes and in relation to extremely long and extremely large oceanic and solar climate forcings the millisecond long periods of residence time from the greenhouse effect are negligible.

I can see what points Bill Illis was trying to get you to focus on though, and why. A pity he failed.

Well, to adopt a similar condescending attitute(!)  I can't see why you, Stephen, don't understand that warm water in a warm room cools slower than the same temperature water in a cold room. What's so difficult about that concept?

(and, yes, I expect an obfuscating reply )

Question Stephen: why do you think energy from greenhouse forcing has a 'millisecond long' residence time?

 

PS. was it Hans Schreuder you were thinking of earlier?

 

"warm water in a warm room cools slower than the same temperature water in a cold room."

The Earth system is open to space unlike a room.

So if a warmer room open to space loses energy faster than a cold room open to space (as it must) there is no reduction of the energy flow from the water to the room.

 

1) The 'extra' time per photon would be very short compared to oceanic energy retention. I've assumed milliseconds for convenience but it wouldn't be a lot more. The increase for a steady flow of extra photons would obviously be permanent but still insignificant compared to what the oceans can achieve or what the sun can achieve via the oceans. Anyway the comparison I was seeking to make in terms of scale was between a permanent change in the greenhouse effect as against a permanent change in the oceanic or solar effects. But whether permanent or temporary the greenhouse effect comes pretty much nowhere.

2) No, Hans denies the thermal characteristics of CO2 molecules and I don't go along with that. However someone else raised similar issues and I thought it wise to check because I had forgotton some of the stuff you refreshed me about.

It's always been an issue of climate sensitivity for me and I'm more aware of the scale of natural climate variability than most having focussed on it over a lifetime.

I think the sheer scale of natural variability is incomprehensible for many but in fact it just all boils down to a shift of the air circulations overhead. Going from one side of a jetstream to another for a period of time gives a huge change in climate regionally.

The same for regions that move closer to or further from the subtropical highs or the ITCZ.

That is all that climate change is. The absolute global temperature matters hardly at all and is not discernible day to day. The Earth cares not a jot whether from time to time there is a bit more energy in the oceans or the air. Natural forces will swamp human influences (globally) at will.