Anthropogenic ocean heating Part 1

Skeptical Science offside

Introduction

Anthropogenic attribution to sea level rise and ocean heat accumulation relies on there being a verified mechanism or process by which rising anthropogenic greenhouse gas (aGHG) emissions impute heat to the ocean. John Cook’s Skeptical Science has been promoting one such posited mechanism in particular as explaining the accumulation of heat in the ocean over the last 40 years or so, the most prominent example being How Increasing Carbon Dioxide Heats The Ocean, posted in 2011 by Rob Painting. That post adapts a 2006 Real Climate article by Professor Peter Minnett, Why greenhouse gases heat the ocean, where an enhanced ocean surface insulation effect was posited.

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…with attractive formatting and with all the references provided as working links.

NOTE: to easily get back here to comment, press the Back button or first load the article in a new tab and swap between them.

You can read the whole article here, but it lacks most of the formatting (which aids understanding) and all of the links (which are provided to assist understanding and to justify what is said). I apologise for any inconvenience this causes, but it takes a long time to convert the word document into the particular html format required by WordPress and to copy each link. So I haven’t done it yet. I’ve converted it to a “standalone” html page so you have access to the links. – RT

What Skeptical Science is saying

Subsequent comments as recent as 6 February, 2013 at Skeptical Science (Duelling Scientists in The Oregonian) promote the in-house opinion that an enhanced insulation effect is the “mainstream view.” For example:

Rob Painting — “As for Stefan Rahmstorf, I know for a fact that he ascribes to the mainstream view that greenhouse gases warm the ocean through the reduced thermal gradient in the cool-skin layer. He was involved in a disagreement between myself and other commenters on Real Climate some months back and made his views on this known.
Is it really any surprise that he agrees with the established research?”

Rob’s facts are off the mark. A minor misunderstanding is that he backs up his claim by quoting a copy of a response Rahmstorf made in the 2006 Real Climate Minnett article thread, thinking it was made in 2012 in view of where he got it from but which wasn’t. More to the point, Rahmstorf was describing the cool-skin effect and Peter Minnett’s posited aGHG modification of it (more on that below). The cool-skin is a natural phenomenon where the upper few millimetres of the ocean surface are cooler than the warm layer beneath (which is about 700mm thick in ideal conditions) because energy leaves the surface, reducing its temperature. The cool-skin is not always present — it can be overwhelmed by solar heating at noon in the tropics, for example. Cool-skin dynamics are documented in Cool-skin and warm-layer effects on sea surface temperature (Fairall, et al., 1996). There is nothing contentious about the cool-skin. Rahmstorf’s 2006 Real Climate response was as follows:

Rahmstorf 2006 — “[Response: I try a different way. To your point 3 the answer is yes – the ocean surface is on average warmer than the overlying air, because the ocean absorbs a lot of heat from the sun, part of which it passes on to the air above. Your confusion arises simply because we are now discussing how the bulk of the ocean below the skin layer gets heated. Thus we are talking not about the gradient between sea surface and overlying air, but we are talking about the gradient through the skin — i.e., the water temperature difference between the top and bottom of the skin layer, which controls how heat flows across this layer, from the bulk of ocean water below to the surface. Obviously, if you heat the top of the skin layer, this reduces the heat flow across this layer from below. Clear? Or still confusing? -stefan]”

Stefan is referring to the idea of heat accumulating via an enhanced insulation effect rather than the actual solar source of ocean heat but even so, if that was his thinking in 2006 he has revised his view by 2013, as will be shown in Part 2. For now just note that Stefan describes thermodynamically conventional and observed (by Fairall, et al.) energy egress from the ocean surface to the atmosphere (sea => air energy transfer). He neglects the egress of radiation direct to space, but no matter. It becomes clear in a 2013 statement made by Rahmstorf that he now subscribes to a fundamentally different mechanism and mainstream view. More on that in Part 2.

Rob Painting (on behalf of Skeptical Science) is stretching the bounds of credibility by describing a single Real Climate blog post as “the established research”. There is work to be done for the Minnett theory to even enter the literature let alone for it to be verified and quantified. And from the Rahmstorf quote, the excerpt “if you heat the top of the skin layer” is highly questionable as will be demonstrated after the following aside. There can only be negligible, if any, heating effect on the cool-skin by downwelling infrared radiation (DLR in the IR-C range) but the very effective seawater heating by noontime solar SW radiation can actually eliminate the cool-skin in the tropics by heating it to warm-layer temperature, i.e., solar energy ingress overwhelms egress in that situation.

An aside

Among other things, my pointing out inconsistencies between what Skeptical Science were asserting and what climate scientists and the IPCC were actually stating must have been embarrassing for Skeptical Science because my last comment (76) on a thread dealing with these issues was retroactively removed and replaced by another as evidenced by the comment sequence:

76. scaddenp at 13:32 PM on 7 February, 2013
77. Composer99 at 17:47 PM on 7 February, 2013
Richard:
Further to your comment #76

Skeptical Science has a track record of this type of revision when the going gets tough; such is the fragility of their case and conviction apparently (also see Part 3 Rahmstorf).

Professor Peter Minnett’s anthropogenically enhanced insulation effect

In the 2006 quote Stefan Rahmstorf expands on the notion that increasing DLR as a result of rising aGHG emissions (which are unproven) heats the top of the skin layer to such an extent that the thermal gradient over a few millimetres of cool-skin from warm layer to surface is modified, creating an enhanced insulation effect so strong that energy egress from the ocean is significantly inhibited. This enhanced insulation, according to the blog theory, accounts for measured late 20th century ocean heat accumulation. Rahmstorf lent credence to this theory in 2006 but as we will see in Part 2 he is certainly not as wedded to it in 2013 as Skeptical Science is.

There are a number of problems with Peter Minnett’s blog theory that need to be addressed. DLR is emitted by all GHG including natural emissions and water vapour (gas). Clouds (liquid water) also contribute, so extracting the anthropogenic component of DLR presents considerable difficulties. The theory is also dependent upon DLR increasing over time (the last 40 years, say) in concert with rising aGHG levels. There is no study that I am aware of over that time frame to provide evidence of that happening. Recent studies that have been done do not return any correlation with CO2, for example, and even the sign of the DLR trend can be opposite the aGHG trend, or when the DLR trend is positive the magnitude can be far greater than can be attributed to aGHG.

What counts most against Peter’s theory is the significance of the insulation effect and this issue was raised in the 2006 Real Climate comments thread by Steven Sadlow but not responded to by either Stefan Rahmstorf or Gavin Schmidt. Stefan Rahmstorf describes the enhanced insulation process as “if you heat the top of the skin layer” but spectroscopic studies (e.g. this plot from Hale and Querry, 1973) show that DLR only impinges on the top 10 microns of the water surface and because of that, DLR is an ineffective water heating agent, DLR having very low energy per photon as compared to solar SW radiation. Fairall et al. state the 10 micron figure explicitly, so no dispute there either. There can only be negligible surface heating (if any) in a non-enhanced situation, because DLR energy will be used up by evaporation in calm conditions which actually aids energy egress. The intensity of DLR is not increased enough by aGHG increase to exacerbate the situation to any level of significance if the insulation effect is already insignificant and there has been no measured increase in DLR intensity. If it was, evaporation and therefore energy egress is actually enhanced. This is a key (but unproven) plank of AGW theory and contrary to Minnett’s theory.

Skeptical Science runs for cover (deletes and replaces comment 76) when asked if the Minnett effect has been quantified, the significance of it established and if so where is the documentation? The most important point regarding the cool-skin phenomenon is that if any of the Skeptical Science associates attempt to claim it in entirety for AGW, don’t believe it. They can claim only a thermally significant modification of the dynamics of it by aGHGs — but only if they can prove the significance of any such modification. Anthropogenic forcing (a tiny fraction of total DLR) would only cause a minuscule change to the warm-layer => surface thermal gradient and that brought about only by a negligible theoretical increment in DLR intensity, the trend of which in reality is wildly inconsistent globally, including decrements.

In any event, Skeptical Science, or anyone asserting that an anthropogenically enhanced insulation effect explains ocean heat accumulation, will have to provide significant and thermodynamically quantified evidence in order to eliminate an explanation involving only solar accumulation. Dr David Stockwell points out in his accumulation theory that only a very small solar forcing is required for ocean heat to accumulate and flow through to the atmosphere.

Stockwell: “…the 20th century temperature rise can be explained by the accumulation of an above-average solar forcing of 0.1 W/m2 in the ocean over the period.”

This concludes Part 1 and Skeptical Science views

Parts 2 and 3 The Improbable IPCC Mechanism and Rahmstorf, Schmittner and Nuccitelli will look at what the IPCC, Stefan Rahmstorf, Andreas Schmittner and Dana Nuccitelli are saying in 2013. It will be demonstrated that — contrary to claims by Skeptical Science — the mainstream view of those named (Nuccitelli’s view being ambiguous) is that the AGW mechanism expected to explain ocean heat accumulation is a heat transfer process operating in the opposite direction to the energy transfer processes described here in Part 1, i.e., an air => sea heat transfer process as opposed to sea => air energy transfer processes. The differentiation of energy forms is deliberate. In the process to be described in Part 2, heat is conventional sensible heat only by inference (much is required from the IPCC if they are to point to DLR as a heating agent) but in these Part 1 processes energy is radiation, evaporation and sensible heat, the respective terms and standard abbreviations being defined in Fairall, et al.

It will also be demonstrated in Part 2 that after 25 years and five assessment reports, the IPCC has yet to firm up a credible anthropogenic ocean heating mechanism (and therefore anthropogenic thermosteric sea level rise). Despite this, the AR5 WGI Chapter 10 SOD authors are “extremely certain” that the increase in global ocean heat content observed in the upper 700 m in the latter half of the 20th century can be attributed to anthropogenic forcing. This is the major issue — the Skeptical Science aspect is only really a sideshow to that.

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Mike JowseyBob DThomasRichard C (NZ)Richard Treadgold Recent comment authors
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Thomas
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Thomas

Sorry, what again where you actually trying to say?? The truth is Mr. Cummings, that the heat loss of the ground including the oceans is the result of a net-flow balance. If you reduce the heat transfer through the atmosphere by adding GHGs you reduce the net heat flow away from the ground simple as that. Less heat flow cooling the ground while the incoming solar energy is kept the same, and your temperature and energy content goes up. There is no two ways about this simple fact and it does not matter how deep over your head you immerse yourself in the interesting science of the details of ocean surface cooling and so on. Wandering into the jungle of scientific details offers many ways for the armchair scientists to walk of cliffs. I recommend to take a guide with you unless you want to get further lost in the thick… The heat accumulation in the Oceans is a matter of fact, well documented and available to all with excellent coverage over at the NOAA site. If you claim that scientists have their thinking wrong about the reasons of that heat buildup, you… Read more »

Andy
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Andy

Thomas, since you seem so expert on the topic of CO2 radiative physics, the commenters at Hot Topic seem to think that Chris de Freitas is “ignorant” of basic physics, and you seem to concur

So do you not accept that the forcing of CO2 is logarithmic to increasing concentrations of CO2? Your latest comment there suggested that we have a long way to go before we see any saturation in CO2 forcing. However, Hansen states that this effect is already evident in his recent post on state of the temperatures.

Maybe I am missing something?

By the way, Gareth’s comment

There’s plenty of evidence that current warming is beyond “natural” variability

has just been refuted by the UK Met Office

Thomas
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Thomas

Andy, since you try to spin a post I made at HT I copy it here verbatim. Let the reader see how the denileraty like yourself constantly take what people say, then spin it just enough to twist the meaning. Don’t Andy, you are simply unmasking your tactics…..

Thomas at HT: The fact that the atmosphere is opaque in the absorption bands of CO2 does not equate to: adding more CO2 will not change the thermal transmissivity of the atmosphere. There is gradual decline in the additional warming effect of additional CO2 but we have a long way to go before that decline gives any hope to alleviate concerns.

I did not suggest that we don’t know about or don’t see saturation effects. I said there is still a long way to go before this will offer relief to our concerns!!!

A good discussion of the effects of increasing CO2 and saturation is once more found at This site

Thomas
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Thomas

Oh and on this Met Office statistical significance nonsense, I thought Andy you had some education in Mathematics from Oxford, or is my memory failing me here?
You among all people then should be able to pick this “statistical significance” illusion that the likes of Bishop Hill and others are so exited about apart.
But gloat on, I am watching the hole getting deeper as you dig down….

Andy
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Andy

I explained the reasoning behind the Keenan post here, just so we don’t clutter this post up with off topic comments.

Andy
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Andy

By the way, thanks to Richards C and T for posting this!

Richard Treadgold
Guest

Yes, thanks, it’s not bad, is it?

Thomas
Guest
Thomas

Yes, so without cluttering this thread with too much stuff, perhaps a brief link to this will suffice.
Needless to say that whoever wants to spin the Bishop Hill rant to make people think GW is not happening needs their mouth washed with soap… On the other hand it is a great example of how some denileraty minds cling to whatever crap to score a point. But it would be good to know which goal is yours and which is not, as this one is a pathetic own goal exposing nothing but the frame of mind of some people…

Andy
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Andy

Thomas, this is not the right thread. If you want to randomly abuse me then I have redirected you to the appropriate place where I have offered my interpretation.

Richard C (NZ)
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Richard C (NZ)

Echo “thanks to” “Richard T” “for posting this!”

Richard Treadgold
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What I’m here for. Two to go.

Richard C (NZ)
Guest
Richard C (NZ)

“Sorry, what again where you actually trying to say??” I thought I’d made that clear. Rob Painting/SkS/Peter Minnett are on-side with convention but off-side with the IPCC in terms of the direction of energy flow. The Minnett conjecture is that normal sea => air energy egress is inhibited, the IPCC are (rather vaguely) implying that air => sea energy fluxes (an energy flow that’s unconventional in terms of predominant direction, note) account for 20th century accumulated heat and that is covered in Part 2. >”heat loss of the ground including the oceans is the result of a net-flow balance.” That in the case of the oceans includes considerable thermal lags anywhere from instantaneous to over 1000 years. Trenberth states 6 and 10 – 100 years in his essay ‘The Role of the Ocean in Climate’. Snapshot in-situ studies observing the AO interface transfers (e.g. Fairall) don’t capture the lag. Trenberth is consistent with others saying the significant planetary thermal lag is 14 years +/- 6 or 12 years (Abdussamatov and Scafetta respectively but from different methods). >”If you reduce the heat transfer through the atmosphere by adding GHGs you reduce the net heat… Read more »

Richard C (NZ)
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Richard C (NZ)

>”Snapshot in-situ studies observing the AO interface transfers (e.g. Fairall) don’t capture the lag”

Fairall doesn’t but ‘Diurnal variation and life-cycle of deep convective systems over the tropical Pacific warm pool’ By SHUYI S. CHEN and ROBERT A. HOUZE Jr (1997) makes a start:-

https://www.climateconversation.org.nz/2013/05/painting-wanting-rebuttal/#comment-201215

Thomas
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Thomas

Richard: You once again run away into the tick of details, where you loose your own bearings quickly – well over your head quite frankly – while hoping to trip up others with irrelevant complications, hand waving and rhetoric. The simple answer remains: If you reduce the thermal transmissivity of the atmosphere by adding GHG such as CO2 and others, you will retain more of the incoming solar energy in the system. Period. The retained heat must cause a rise in temperatures, melting of ice, expansion of ocean waters etc. and a mix of all this, until a new higher temperature regime of the surface once again looses the same energy per time as it receives from the Sun and a new equilibrium at that higher temperature regime is established. All your excitement about the intricate details of the air-ocean interface, time lags or anything else, is an afterthought. Don’t even go there unless you understand the basics. It is of cause very interesting from a science perspective to understand all about the detailed mechanisms and timings of heat distribution in the Earths ocean and atmosphere systems, but all this is not changing… Read more »

Bob D
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Bob D

Thomas:

And we OBSERVE (facts you know) warming of the surface and warming of the oceans of the magnitude we expect.

Uhh, no, sorry. We expect 0.22°C/decade (model mean SRES A1B scenario), but we aren’t seeing it.

Thomas
Guest
Thomas

Uh, no sorry Bob, the lineal trend over the last 4 decades (1970-2013) has been (not a model, measurements) very close to 0.2 C/decade, well within the range of model predictions.
Play with the data yourself:
http://www.woodfortrees.org/plot/gistemp/from:1970/to:2013/plot/gistemp/from:1970/to:2013/trend

Bob D
Guest
Bob D

Thomas: “…the lineal trend over the last 4 decades (1970-2013) has been (not a model, measurements) very close to 0.2 C/decade, well within the range of model predictions.” OK, let’s start with the Godfather of AGW, James Hansen. He said this at the end of the 1980s (Hansen, 1988): “Our model results suggest that global greenhouse warming will soon rise above the level of natural climate variability.” In other words, taking a time period from 1970 is pointless, as any hypothetical GHG warming is less than natural warming anyway. He goes on: “The single best place to search for the greenhouse effect appears to be the global mean surface temperature.” Just as an aside, this means not the deep ocean. “If it rises and remains for a few years above an appropriate significance level, which we have argued is about 0.4°C for 99% confidence (3σ), it will constitute convincing evidence of a cause and effect relationship, i.e., a “smoking gun,” in current vernacular.” The expectation was that in the 1980s the AGW signal could not be detected, and wouldn’t be until the 1990s: “We concluded earlier that the magnitude of global mean greenhouse… Read more »

Richard C (NZ)
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Richard C (NZ)

>”The simple answer remains: If you reduce the thermal transmissivity of the atmosphere by adding GHG such as CO2 and others, you will retain more of the incoming solar energy in the system. Period.” Yes but negligible effect compared to water vapour – the major GHG. >”The retained heat must cause a rise in temperatures, melting of ice, expansion of ocean waters etc. and a mix of all this, until a new higher temperature regime of the surface once again looses the same energy per time as it receives from the Sun and a new equilibrium at that higher temperature regime is established.” Now that the sun’s input to the system is reducing, there’s no longer gain since the system obviously reverses from gain to loss. The reversal has started with the upper Pacific and Atlantic cooling this century in accordance with planetary thermal inertia (SST cooling too). The 21st century atmospheric temperature standstill has so far been due to change of phase of ocean oscillations but there has been enough contribution from ocean heat release to sustain levels. That situation cannot last because there is already less direct solar heating of the… Read more »

Richard C (NZ)
Guest
Richard C (NZ)

Following on from my reply:-

>”Yes but negligible effect compared to water vapour – the major GHG.”

Thomas, I suggest the following:-

1) Compare the specific heat capacity of dry air to the specific heat capacity of air containing a nominal atmospheric average proportion of water vapour (say 2.5%).

2) Holding the water vapour composition at 2.5%, compare the specific heat capacity of air with carbon dioxide at 0.04% to the specific heat capacity of air with no carbon dioxide constituent.

3) Consider 2 in view of 1.

Mike Jowsey
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Mike Jowsey

Here, here! RC, I’ve only read parts 1 & 2 so far, but have found it very interesting and clearly presented. You’ve put a lot of research into it. Many thanks.

Mike Jowsey
Guest
Mike Jowsey

Thomas, you say: Less heat flow cooling the ground while the incoming solar energy is kept the same, and your temperature and energy content goes up.

However the observed surface temperatures for the last 17 years do not show temperature and energy going up. So your side are now saying it is going into the oceans. Richard C’s clearly written and well researched article explains the problems with this theory.

Richard C (NZ)
Guest
Richard C (NZ)

‘La Niñas Do NOT Suck Heat from the Atmosphere’ by Bob Tisdale Over the years I’ve seen a statement similar to the one made by MarkR in the SkepticalScience post The 2012 State of the Climate is easily misunderstood (my boldface): “Global surface temperatures were the 8th or 9th highest recorded, partly because the first two months were cool-ish thanks to a La Nina in the Pacific, where cooler waters sit on the top of the ocean and suck up heat from the atmosphere.” The error in MarkR’s statement, which has been repeated many times before, may stem from the assumption that La Niñas are the opposite of El Niños. That is, it is well known that El Niño events release enormous amounts of heat from the ocean to the atmosphere. I assume the flawed logic is that La Niña events must then remove heat from the atmosphere. The vast majority of heat released from the ocean to the atmosphere, however, occurs through evaporation. It’s likely those assuming that La Niñas “suck up heat from the atmosphere” are thinking only in terms of “sensible heat flux”. SENSIBLE VERSUS LATENT HEAT […] As illustrated… Read more »

Richard C (NZ)
Guest
Richard C (NZ)

Frölicher’s caught the attention of Anthony watts:

The ‘worse than we thought’ model

From ETH Zurich: Underestimated future climate change?

http://wattsupwiththat.com/2013/11/25/the-worse-than-we-thought-model/

They’re not buying ““Much of the …….heat trapped by the CO2 goes into the ocean sooner or later” rubbish in comments.

Richard C (NZ)
Guest
Richard C (NZ)

>”They’re not buying……”

jorgekafkazar says:
November 25, 2013 at 7:47 pm

“…the heat trapped by the CO2 goes into the ocean sooner or later…”

Applesauce, balderdash, baloney, bilge, blarney, blather, bosh, bull, bunk, claptrap, codswallop, crapola, drivel, drool, garbage, hogwash, hokum, hooey, horsefeathers, humbug, malarkey, moonshine, muck, piffle, poppycock, punk, rubbish, tommyrot, tosh, trumpery, twaddle, whatlysenkospawned.

http://wattsupwiththat.com/2013/11/25/the-worse-than-we-thought-model/#comment-1484317

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