Listen Robert Kilroy Silk, we shall jolly well feed our trolls if that's what we wish to do.

Some trolls are more fun to feed than others, this one has passed its 'feed by date', though.

Some trolls are more fun to feed than others, this one has passed its 'feed by date', though.

Some trolls are more fun to feed than others, this one has passed its 'feed by date', though.

Thanks Squarespace, for repeating me.

You are welcome, BigY

Mike Jackson,

Have a read up on the MOC (meridional overturning circulation) which is posited to explain this. Warm water cools at high latitude and sinks to the ocean floor, "allowing the atmosphere to come in contact with the deep ocean" as one pithy advocate website put it.

What they gloss over is that in order to reach the depth of the ocean floor, the water has to cool and become more dense, so by the time it gets there it has no heat to transfer to the deep ocean. They get around this by positing that evaporation causing increased salinity (and thus density) forces salty water deeper than it would go based purely on temperature-driven density (thermohaline).

As a mechanism, it sounds quite shaky to me. How much evaporation would it take to get enough of a density difference to create a temperature difference at the ocean floor, enough to store all the missing heat? Has any of it been measured? The evaporation, the sinking water, the amount of energy, the raise in ocean temperature ?

This probably deserves its own discussion topic.

RKS,

My biggest problem with it is why is only the "extra" heat from global warming trapped down there?

The deep ocean water is around 0-3 degrees, which is way colder than the atmosphere. Why doesn't this cooling engine take ALL the heat out of the atmosphere until the two are equalised? Why would it stop at just the extra heat that we are supposed to have from global warming.

Something smells.

@Mike Jackson

There is also doubt over whether it really is the Gulf Stream that keeps the climate of the UK and Western Europe mild for the latitude: New Simulations Question the Gulf Stream’s Role in Tempering Europe’s Winters. Seems like the Gulf Stream idea was just one of those things that was accepted without any empirical evidence.

It seems to be accepted (dare I say the consensus) among people who study oceans that the MOC exists. I expect that there are many aspects to the circulation, including temperature and salinity differences, Coriolis effect, momentum maybe. If the circulation works, however it works, with a tropical sea temperature of 30C and a North Atlantic temperature of say 1C (guess), is there any reason to expect it suddenly to stop working with temperatures of 30.01C and 1.01C respectively? Maybe the sinking water would reach slightly less depth with its marginally higher temperature but it is still going deep. So extra heat (the 0.01C) gets taken to depth.

Why doesn't all the heat of the atmosphere get sucked down there? Well its been that way for millions of years so the 'smell' is probably our ignorance, not some scientific incompetence or conspiracy. Oh and remember that the sun heats the atmosphere and the top of the ocean. (BTW waves are probably pretty good at mixing surface waters, don't you think? Or is your preferred ocean as calm as a mill-pond?) And note that there is a steady flow of very cold dense water from the poles to the depths each winter. And then there is the MOC taking some warmth down there and mixing it up. One might think that over time there might be an equilibrium or something...

RKS,

they need a theory to explain it, and that is it. Sounds even more ropey than the original CO2 premise if you ask me. Both of these mechanisms (radiative and halothermal) seem to be heavily regulated by evaporation and convection, and are probably completely swamped by them in the real world.

And the painful truth for them is that they don't understand H2O effects enough to say either way.

Lord Rutherford famously said; "If you can't explain your theory to a barmaid, it probably isn't good physics."

So yesterday evening I tooled down to the pub and tried to explain to the barmaid why heat could transfer itself to the deep oceans. She found my explanation incomprehensible, because, as she pointed out warm water would be less dense than cold water and would be incapable of sinking below it unless it was, in her, words, "A good kick up the arse." I told her that a famous scientist, Dr. Trenberth had said this could happen so she would do well to watch her tongue, to which she replied, "Then he doesn't understand the Meridional Overturning Circulation and wants a good kick up the arse.". I said it was postulated that the water at the surface evaporated and became more saline making it denser so it sank to the bottom with the heat. and she said, "That's interesting the denser water sinks 2000+ meters in cold water giving off photons at the speed of light and it still carries heat to the bottom of the ocean, as soon as I've cleaned these glasses I'll do the sums to see if that's possible." About five minutes later I felt a sharp pain in my posterior and turned to find the barmaid brandishing a slide rule, she looked me straight in the eye and said, "It's bollocks now get out of here before I give you another kick up the arse."

Mike,

It's not so much that warm water can't sink below cold - it's all to do with density. (this has the look of a colder object warming a hotter object argument!)

The reason warm water doesn't usually sink below cold water is because the density for equal salinity water is controlled only by the temperature. But salinity adds another way to control density - more salt dissolved makes it denser, so it can be more dense and sink without it being having to be cooler. There's nothing in physics forbidding hot things going under cold things, it's just that for well mixed water (and air) - the only thing that can change density is temperature.

Imagine salty water coming up from the equator near the surface and meeting ice-melt water at the Arctic circle. The equator water is less dense - at first- due to its higher temps, but as it cools it becomes more dense - and soon is more dense than ice-melt, due to salinity, so tends to sink under the ice-melt. Winds cause some evaporation, which only takes the water and leaves the salt, leading to even higher levels of salinity.

Soon the warmer (but only a little warmer than the ice-melt) water is sinking fast, to deep levels. In effect, some heat is transported to the deep ocean, where it is circulated around the globe.

While I have no particular problem with it as a mechanism, it suffers from the same problems as the radiative effect of CO2. It's an idealized concept derived from the known properties of the agents involved. It may happen in a macro world, or it may not. How much? Is anyone measuring it? is it large enough to account for the missing heat?

So now we have the ridiculous situation where one badly understood theoretical cooling mechanism is magically accounting for the heat which is supposed to be produced by a badly understood theoretical warming mechanism. Both of these depend on evaporation and convection. Neither of them can be measured directly.

So we could have a huge GHE being cancelled out by a huge MOC effect, or an insignificant GHE effect being cancelled out by an insignificant MOC effect. Of we could have nothing cancelling out nothing.

I don't see how the multiplication of mythical beasts is helping the AGW cause here.

In discussing the "missing heat" question, everybody should be aware there's a fundamental disagreement between Hansen and Trenberth: Trenberth says there's missing heat that needs to be accounted for; Hansen says climate models were overestimating the amount of energy in the climate and there is therefore no missing heat.

See Provoked scientists try to explain lag in global warming:

Over the past decade, for the first time, scientists have had access to reliable measures of the ocean's deep heat, down to 5,000 feet below sea level, through the Argo network, a collection of several thousand robotic probes that, every few days, float up and down through the water column. This led Hansen to conclude that net energy imbalance was, to be briefly technical, 0.6 watts per square meter, rather than more than 1 watt per square meter, as some had argued.

(Recently, the satellite group measuring the energy imbalance has revised its figure, which now sits at 0.6 watts, matching Hansen's estimate, according to Graeme Stephens, the head of NASA's Cloudsat mission. It suggests there isn't a missing energy. Trenberth disagrees with this analysis, and it's likely to be a question of ongoing debate.)

If Hansen is correct, then we're not going to get bitten on the bum by the "missing heat" emerging from its hidey-hole in the deep oceans when the current hiatus comes to an end.

If Hansen is correct, then we're not going to get bitten on the bum by the "missing heat" emerging from its hidey-hole in the deep oceans when the current hiatus comes to an end.

I wonder if any bookies are taking bets on the hiatus resuming. I wouldn't mind punting a bit of money on it not resuming any time this century.