The experiment is run on a climate model which of course includes absorption of solar radiation by the oceans and has the atmosphere maintaining a real temperature; no GHGs does not mean that there is no energy transfer to the atmosphere. You're making pretend that climate models only include GHGs and leave out lots of other important stuff, which is simply not true.

The water cycle would not go completely inactive but just much less active.

Yes this is the issue and not one easily resolved. Various lines of evidence point to about 1.4C equilibrium warming since the start of the industrial revolution, of which we've seen about half so far. Your view relies on several assertions that I don't think are backed up by science, but we've discussed them ad nauseam elsewhere.

The oceans are not magically able to prevent ice ages, in which we still have significant greenhouse effect with 180ppm CO2 and a pretty active hydrological cycle with the cooling at the equator being much less. The scenario with no greenhouse effect results in an even colder Earth. The oceans can only do so much to stabilise global temperature, as even they have to obey the laws of thermodynamics and cool down if they absorb less energy than they emit (if more of the surface is frozen or the overlying air is much colder, for example).

I don't see it as having anything to do with AGW.  

But it does have important implications with regards Snowball Earth scenarios: if atmospheric CO2 drops below a critical level, we freeze.  Then, like a stalled engine, the atmosphere needs a kick-start with a boost of fresh CO2 to get it working again and warm us back up.   Which is exactly what appears to have happened and thus, regardless of whether Earth was a snowball or just an icy slushball, we have a mechanism which explains observations.  Neat!

 

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"The oceans are not magically able to prevent ice ages."

I don't suggest that they could.However, even during ice ages there is lots of solar shortwave entering the oceans around the equator and the oxygen and nitrogen still gets warmed by conduction.

There would still be enough energy for a water cycle and thus convection and evaporation as long as the solar shortwave input is enough to keep surface temperature nearer the equator above freezing.

If the model being used included such aspects I don't see how they could come to the result given. Even by your account there would still be a water cycle and not a sudden freezing up of everything which is what they propose.

As for Essan's comment I fail to see where an injection of fresh CO2 would come from once we have the snowball or slushball. Indeed, what would have made the CO2 go away in the first place ?

Even in an ice age the non-IR-active gases are still warmed much more by collisions with GHGs and latent heat release than they are by direct conduction from the surface, which is always a very small quantity. Indeed even with no non-condensible GHGs the small amount of water vapour would warm the O2/N2 much more effectively than direct heat transfer from the surface.

Anyway, the point is that even though we have oceans, they didn't stop the Earth plunging into an ice/slushball state when prevailing conditions allowed.

"Anyway, the point is that even though we have oceans, they didn't stop the Earth plunging into an ice/slushball state when prevailing conditions allowed."

Nor did GHGs apparently.

What matters is solar shortwave input to the oceans.

And the continuation of water oceans despite the iciness is what pulled the Earth out of the situation again. It certainly wasn't an increase in GHGs. The sun drilling into the available liquid surfaces comes first and the GHG increase later.

An upsurge in volcanic activity?  perhaps triggered by the crustal pressure of a growing ice sheet?

As to why it went away, what happens when you introduce something into an ecosystem which removes and essential component of that ecosystem?

What happened when stromatolites first appeared on Earth?  Did the first advanced life forms nearly end it all for everyone?

(no doubt any geologist specialising in the era will point out the errors in that scenario, but it cvertainly seems a possibility)

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http://www.nature.com/nature/journal/v429/n6992/abs/nature02640.html 

That link also says this:

"In my simulations, the system remains far short of deglaciation even at atmospheric carbon dioxide concentrations of 550 times the present levels (0.2 bar of CO2). I find that at much higher carbon dioxide levels, deglaciation is unlikely unless unknown feedback cycles that are not captured in the model come into effect."


So there is lots of doubt.

Even the concept of 'snowball Earth' is somewhat speculative.

Of course Stephen, I never meant to imply otherwise

But it's certainly an interesting area of research.

You keep making these bold statements Stephen but we are still waiting for anything resembling data to support them.

Your statement is just too simplistic to be taken seriously.  If there were liquid surfaces then by what mechanism did the ice form and extend to cover much of the oceans away from the tropics?  Something else was going on - as Stu comments.

 

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Yes I agree Gandalf and I had actually missed this earlier statement from Stephen. How would it get into an icebound state if Stephen's hypothesis is correct? You need more than just the fact that there is some open ocean absorbing some solar radiation.

Yes, Stu.  What troubles me is that we have guests visiting this site and reading these threads and Stephen holds himself up to be some sort of guru of climate science who has these penetrating insights into how the climate system works.  Superficially sometimes it looks quite persuasive but he keeps making these statements that just don't reflect any sort of scientific reality as I, even with my limited understanding, recognise.

This does rather reflect the comments on the Horizon programme about the proliferation of 'opinion' on the Internet and the fact that it is difficult to differentiate this from proper peer-reviewed scientific study.

Lest Stephen respond with further comments about 'playing the man' this is purely about style and content, whether it be Stephen or anybody else.

 

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We are all guests visiting this site! We are all entitled to our opinions, and raise questions resulting from the incomplete knowledge of our climate system - and that doesn't trouble me. It is actually very easy to differentiate between this forum and 'proper peer-reviewed scientific study' (is there a definition of what counts as that?!). Belittling those making a genuine attempt to understand the science and, through debate, discussion and argument, helping to advance the knowedge of many of us interested non-specialists is not very constructive. Many of today's climate scientists are in highly specialized disciplines: who is there left entitled and qualified to give us a comprehensive overview of climate science, AGW and climate prediction?

Thanks Marcus.

The fact is that I've never held myself out as some sort of guru. Everyone knows I am not a professional scientist or can easily find out.

What I do is spot inconsistencies between observations and established theory. There are so many that that is not difficult. I then formulate a scenario that could account for the observations and put it up for challenge. Sometimes I make incorrect assertions which if pointed out then results in an adaptation of the scenario but I will persist until such adaptations become untenable and thereupon I withdraw or approach the issue from another angle.

I am actually using the other participants here as a quality control service for a climate description that is steadily increasing in precision and scope.

It has been surprising how little of substance there really is behind the assumptions of AGW.

I think that the reason I irritate Gandalf and some others is that I present a challenge to their pretensions of AGW guruhood.

StuN asked:

"How would it get into an icebound state if Stephen's hypothesis is correct? You need more than just the fact that there is some open ocean absorbing some solar radiation."

Well there is a lot of doubt that it ever did achieve an icebound state just because of the problem of closing the gap at the equator. That is why the slushball Earth was proposed as a compromise.

Even if the gap at the equator did close then periods of high solar insolation would create a liquid surface skin on the ice from time to time and the melt process would get under way.

The first suggestion that an icebound state ever existed arose from evidence that all the landmasses have been under ice from time to time but the easiest explanation for that is continental drift.

Unless someone can point to evidence that aspecific land mass was covered in ice at sea level at the equator that is. If that had been found I'm sure I would know about it but if I missed it please now show me.

But, that's not to belittle them?

Gandalf asked:

"If there were liquid surfaces then by what mechanism did the ice form and extend to cover much of the oceans away from the tropics?"

We have seen recently that a quiet sun quickly results in a negative polar vortex, more equatorward/meridional jets, increased global cloudiness and albedo with less solar energy penetrating the oceans.

There is no reason in principle to deny that from time to time a long period of quiet sun combined with astronomic influences could facilitate such a large reduction in solar input to the oceans that ice from the two poles could spread beyond the subtropics and even in extremis result in a snowball or slushball Earth.

The recovery would arise from a simple reversal of the same factors.

I think you know what I mean when I use the word 'Guest' Marcus. For the avoidance of doubt I mean those not registered on the TWO Forum and therefore visiting, i.e. reading but not contributing.

According to the dictionary "belittle' means to make someone or something unimportant.  That is hardly the applicable label is it?  You make a strange observation about "all entitled to our opinions" and then in the same post you imply that I am not entitled to mine?

I stand by my observation.  Stephen implies a level of confidence and certainty that is entirely unjustified and misleading.

You will see from his posts that his stance is anything but "a genuine attempt to understand the science" and entirely about belittling the entire science of AGW and those who accept it.  If you need proof just read his follow up post in response to yours.

 

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Devonian asked:

"But, that's not to belittle them?"


How can acknowledging someone else's ability to improve my work constitute 'belittling' ?

Stephen, you are doing what you did with the swimming pool analogy - missing the point again.

The point I was making was that your assertion that some open water alone was sufficient to reverse the 'snowball Earth' state was clearly incorrect. 

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Gandalf said:

"The point I was making was that your assertion that some open water alone was sufficient to reverse the 'snowball Earth' state was clearly incorrect."


I didn't exclude other factors. I just pointed out that they do not seem to be essential. How about you explaning why you think solar shortwave into the oceans could NOT be sufficient.

You irritate me - and others - because, inter alia:

• you assert a level of certainty in your arguments that you deny to anyone else.


• you are not prepared to support your theories with hard facts


• You scoff at the case for AGW when you have scant evidence for your position


• You are inclined to overdo the arrogant self-publicising

The bold part of your post is just a futile attempt to play back my use of the word 'guru'.  I used the word adivsedly - you are just using it for effect - again,

As for challenge - please do demonstrate how your theories prove the work of thousands of climate scientists wrong and how the data supports your theories. If you were capable of doing this in any sort of reasoned, supported and sensible way then I might be interested.

 

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My bad. I guess when you say "I think that the reason I irritate Gandalf and some others is that I present a challenge to their pretensions of AGW guruhood." it's acknowledging someone else's abilty to improve your work

Anyway, it's nearly time to watch the you know who

Well that's not what you said. If you are changing or correcting your original post then that's fine.

How does solar radiation affect ice covered ocean?

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Gandalf:

Please calm down. I have put up with far more from you than I have subjected you to (in my humble opinion).

Most people here know full well that your rant is unfair.

I have posted lots of links and data where it is available in support of the scenarios that I put forward.

I've also made it clear often enough that whatever I say is open to challenge. I am here specifically to receive challenges and consider them. I never promised to give in without a fight because that is the best way for both sides to learn.

Why do you think my discussions with StuN are calmer than mine with you ? He knows a lot of technical stuff that I don't and puts it forward constructively. All you can do is tell me that the people you choose to believe know more than me so I should shut up even though the people you believe are unable to deal with the inconsistencies in their own performances.