This comment seemed like a useful question to discuss, so I’m elevating it to post status
A. Patterson Moore says:
I see ocean heat content discussed here and elsewhere from time to time, but I have never seen a discussion of what causes it to increase. The clear implication is that it is increasing because of warmer atmospheric surface temperatures, but that makes no sense to me.
Surely the small increase in warming of the atmosphere to date could not transfer a significant amount of heat to the oceans. It seems obvious to me the only way that the oceans could accumulate much heat would be through direct heating from solar radiation. If that is occurring, wouldn’t that be direct evidence of a decrease in cloud cover, instead of evidence for AGW?
If you view the earth from space the oceans look dark and the land looks bright.
When my black and white dog lays in the sun the white parts are cool and the black parts are hot.
Simple answer but true.
Dennis Nikols, P. Geo. says:
May 11, 2011 at 9:30 pm
Right on the money, no maybe.
“”Harold Pierce Jr says:
May 11, 2011 at 2:35 pm
This is incorrect and speculation.””
More up to date information here:
http://wattsupwiththat.com/2011/05/12/another-cloudy-geoengineering-scheme/#more-39742
I’ve also long pondered how the physics works when you consider that the oceans contain ~ 3500 times more heat storage capacity than the atmosphere.
Someone needs to ask this question over at ‘Real Climate’ !
While the main supply of heat probably comes from the sun, it would be interesting to know how much originates from volcanic action. I have read that, for instance, ‘smokers’ can have a temperature of several hundred degrees. we do not know just how many of these there are and how much direct heating originates from the earths crust in the vicinity of volcanoes.
The sun heats the ocean. The atmosphere can throttle how much sunlight reaches it through, for instance, clouds. The atmosphere can also throttle how much heat leaves it through, for instance, water vapor acting as a greenhouse gas.
Holy cow, so many responses…I can’t read them all. I have a question, which I hope is pertinent. What is the largest source of water in-flow to our oceans? Is it direct precipitation or flows from rivers? The reason I ask is that the thought occurred to me that perhaps if it was river flow then maybe the rivers are picking up extra heat from the land that it courses through and which the water that it is sourced from has picked up along the way? Could it be that with increasing levels of urbanization, for example, and all the ashphalt and concrete that are hallmarks of ubanization, maybe the rain water/snow melt is picking up slightly extra heat, which in turn flows eventually into all the oceans? I don’t know if my idea is off base, but I thought I’d just ask.
As I understand it the heat capacity of the ocean is 1000 x that of the atmosphere. So it seems to me that in this dog-tail wagging situation, the dog is the ocean and the tail is the atmosphere. This is easy to see with the wild temperature swings we get during El Nino and La Nina.
I have no evidence for the above of course. The ocean could be heated by a giant underwater Atlantis barbecue for all I know.
“The atmosphere can also throttle how much heat leaves it through, for instance, water vapor acting as a greenhouse gas.”
Well yes, but the amount of water vapour varies very little.
The speed of the water cycle varies instead and cloud quantities would be involved in that.
So the clouds/water cycle adjust the energy flow through the system, either accelerating or decelerating as necessary to try and maintain the temperature equilibrium between sea surface and surface air against disruptive variable forcings from sun and oceans.
Normally forty percent of the earth is not cloud-covered and a receives a full dose of solar radiation. But that is statistics. It could and I am sure it does vary. Why don’t we have satellites tracking the percentage of cloud cover on the sunlit side of the earth and reporting it? It seems like it could be a vital statistic. We don’t know how much it can vary and on what time scales but if we did it could probably tell us much about the climate and the weather.
Alex the skeptic says:
May 12, 2011 at 4:25 am
“WUWT and its readers, in this post have achieved in a few hours and at no financial cost, what many scientists paid by our taxes have not achieved in 30 years of scientific grants, endless peer-reviewed reports and climate- and other gates.”
Right on the money. Nothing more important can be said in climate science today.
Gordon Walker says:
May 12, 2011 at 2:40 am
Stephen Wilde:
“By the way Chris Colose, your fundamental misunderstanding comes from one of my bugbears which is that there is a common mistaken belief that CO2 (or any GHG) warms the ocean when in fact it only slows the rate of cooling.”
“Quite correct, and I have seen a few warmistas admit this and the consequence that the warming will tke place mainly in higher latitudes, mainly in winter, and mainly at night, with mostly beneficial results. So we will not all fry after all!”
Warmista are incapable of holding this point in the mind’s eye for more than a moment because its destructive consequences are disastrous for their Manmade-CO2 “hypothesis” (actually hunch). The disaster is that any increase in daily high temperatures cannot be attributed to the effects of manmade CO2 and must be attributed to something else. Of course, that fact means that the unaccounted for increase in daily high temperatures must be subtracted from any increase in night time minimum temperatures – because that part also cannot be attributed to manmade CO2.
Don’t know the answer, but as a thought experiment, assume that it rained equally all over the Earth. Since land is only about a 30% of the Earth’s surface, and since the rivers all stem ultimately from precipitation, then rainfall would account for 70% of the inflow to the seas. Of course, it may be that land topography triggers more precipitation than the expanse of the sea, and the rivers may indeed pick up some warmth—but a significant amount? I’ll leave that to the experts here to elucidate.
/Mr Lynn
Hi Anthony. I recall seeing a heat change profile of the oceans and was struck by indications that, while the upper 700 m of the ocean is fairly constant there has been a slight increase in heat content below that.
At that depth I think we can count out solar effects and heat conduction from the surface. That leaves physical and chemical processes. There has been a good deal of geological and tectonic activity in recent years; I don’t know if there is a change in output of heat vents. So this is one thing to look at.
But I think a large, overlooked factor is the chemical input. As we know carbonates are being formed continually deep in the ocean. Further, this process is exothermic — i.e., it produces heat. The only thing that’s missing is knowledge of the actual scale. If this produces negligible heat in comparison to the observed changes, then I suppose it can be ignored. But I haven’t seen any analysis of this. Perhaps some visitor to the site has knowledge of such things.
I’m afraid the AGW myth will never die. Just because it is useful for corporations and politicians.
I’d add to Roy Clark’s excellent explanation above,
The theory is that increasing atmospheric CO2 and other GHGs warms the atmosphere, and a warmer (and more humid) atmosphere retards heat loss from the oceans, and hence the ocean’s heat content increases.
Increasing ocean heat content is therefore a secondary effect of increasing atmospheric CO2.
As the oceans warm, a new equilibrium is eventually reached where the oceans release as much heat as they gain from solar heating.
I stress this is the theory and there is limited data to confirm this process is actually happening.
So, increasing ocean heat content is confirmation that GHG atmospheric warming is occuring. Although there could be, and likely are, other contributing factors such as changes in solar insolation.
Were ocean heat content not increasing, then this would be strong evidence that GHG warming is not occuring.
We only have good ocean heat content (Argo) for less than 10 years and we need quite a few more years data to be sure the warming that is occuring isn’t due to ocean cycles and is in fact a signature of GHG warming.
Can anyone explain the physics of how greenhouse gases warm the oceans by backradiation?
This has been talked about for so long there should be reams of papers available on the web that explain this phenomenon so a layman like myself can understand how it works.
Just one link will do for starters please.
“Can anyone explain the physics of how greenhouse gases warm the oceans by backradiation?”
It can’t, but one scientist tried to set up a theory involving the ocean skin. However I think I have explained why that theory doesn’t fly.
The subject was canvassed in some detail here:
http://climaterealists.com/index.php?id=4245
Since then I have come to the conclusion that the net effect of DLR on the ocean surface as regards the rate of energy flow from ocean to air is zero rather than net warming or net cooling.
The reason being that the increased evaporation from more DLR is a self limiting process. When the DLR has been used up the increase in the rate of evaporation stops.
You might also like to consider this:
http://en.wikipedia.org/wiki/Enthalpy_of_vaporization
“the molecules in liquid water are held together by relatively strong hydrogen bonds, and its enthalpy of vaporization, 40.65 kJ/mol, is more than five times the energy required to heat the same quantity of water from 0 °C to 100 °C (cp = 75.3 J K−1 mol−1). ”
In other words the process of evaporation removes from the local environment (in the form of latent heat) five times the amount of energy required to induce that evaporation.
In the face of that energy imbalance the extra DLR has no opportunity to heat up anything other than the specific molecules that then evaporate earlier than they otherwise would have done.
The reason for the size of that imbalance is atmospheric pressure and the relative densities of air and water but that is for another day. Just note that water boils at a lower temperature at the top of Everest.
If ocean heat were rising there would be thermal expansion, resulting in accelerating sea level rise. But that is not happening, so the typical data massaging is applied.
“”Stephen Wilde says:
May 13, 2011 at 10:04 am
The subject was canvassed in some detail here:
http://climaterealists.com/index.php?id=4245 “”
Thanks for that link.
Richard111 says:
May 13, 2011 at 9:30 am
Can anyone explain the physics of how greenhouse gases warm the oceans by backradiation?
;——————————————————————————————————
The existence of a greenhouse gas is an urban legend.
Or stated slightly differently, how a greenhouse works has absolutely nothing to do with the heat capacity of a gas.
All gas molecules have translation and rotational degrees of freedom – polyatomic molecules have additional vibrational degrees of freedom.
The degrees of freedom are used to calculate the heat capacity of a gas.
The rotational degrees of freedom are excited by microwave radiation.
The vibrational degrees of freedom are typically excited by infrared radiation.
However, for vibrational degrees of freedom, since the thermal energy at room temperature is small compared to the spacing between vibrational energy levels, for all practical purposes, you can ignore the vibrational degrees of freedom for temperatures below 30C.
Note, gases can not cause heating – heat causes heating. They can, however, retain heat for short periods of time by virtual of their heat capacity.
Backradiation is a conjecture which violates both the 1st and 2nd laws of thermodynamics.
What about the mid-ocean trench? It’s 80,000kms of active, undersea volcano. Surely it must act like a heating element in a kettle?
There is only one mechanism that can warm the surface sea/ocean from the atmosphere and that is by convection. This convection only occurs when winds blow warm air from land over onto the coasts towards to sea/ocean. This is limited to so many miles away from the coast and will have no affect once reached a certain distance away. The rest of the ocean surface (~98 percent of it) convection has no affect and the atmosphere can’t warm the surface because the temperature is less than 0.5c difference between the surface and 2m above it (with the 2m temp normally cooler – gets cooler with increasing height).
Latent heat always has much larger influence then any change this 0.5c has. Therefore this comes about to the only possibilty, can the 2% warm the entire world oceans. The simply answer is no because energy gained during the Summer months is lost during the Winter by convection, but of course with much cooler air. (this can be observed by looking at SST’s through the years) Depending on weather patterns and tropics, the 2% warming or cooling of coastal areas is never reached anyway.
Increasing ocean heat content is not confirmation that GHG atmospheric warming is occuring. This is due to other factors do cause the ocean heat content to rise and there is no evidence that GHG’s can increase the actual heat content. The only evidence so far is it can retain energy a bit longer in the skin layer. This tiny energy gain is easily lost and therefore balanced out during the night period, when there is of course no SWR to maintain it. Nevermind, as mentioned before that evaporative cooling exchanges, far larger energy amounts on a daily basis (orders higher).
El Ninos and albedo have a large influence on short wave radiation (SWR) reaching the ocean surface and therefore do change the ocean heat content. Global cloud albedo has declined over recent decades until this century, when it had stabilised, until a very recent increase. Too much a coincidence that global temperatures have also stabilised too? (I don’t think so) A one percent change in global cloud levels is easily enough to have influence on ocean heat content and global atmospheric temperatures. Especially when SWR not only warms the ocean, but also controls them too, with El Nino and La Nina there common sign of energy transfer around the ocean via albedo.
Increasing ocean heat content is not confirmation that GHG atmospheric warming is occuring. This is due to other factors do cause the ocean heat content to rise and there is no evidence that GHG’s can increase the actual heat content. The only evidence so far is it can retain energy a bit longer in the skin layer. This tiny energy gain is easily lost and therefore balanced out during the night period, when there is of course no SWR to maintain it. I’m not the first that mentioned evaporative cooling exchanges, far larger energy amounts on a daily basis (orders higher).
El Ninos and albedo have a large influence on short wave radiation (SWR) reaching the ocean surface and therefore do change the ocean heat content. Global cloud albedo has declined over recent decades until this century, when it had stabilised, until a very recent increase. Too much a coincidence that global temperatures have also stabilised too? (I don’t think so) A one percent change in global cloud levels is easily enough to have influence on ocean heat content and global atmospheric temperatures. Especially when SWR not only warms the ocean, but also controls them too, with El Nino and La Nina there common sign of energy transfer around the ocean via albedo.