Arguments
Why ocean heat can’t drive climate change, only chase it
The skeptic argument...
It's the ocean
"These small global temperature increases of the last 25 years and over the last century are likely natural changes that the globe has seen many times in the past. This small warming is likely a result of the natural alterations in global ocean currents which are driven by ocean salinity variations. Ocean circulation variations are as yet little understood. Human kind has little or nothing to do with the recent temperature changes. We are not that influential." (William Gray)
What the science says...
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| The oceans are warming and moreover are becoming more acidic, threatening the food chain. | |||||
The argument attributing the warming of the Earth to heat being released by the oceans was clearly articulated by William M Gray, one of the world’s foremost experts on tropical storms. Unfortunately, his views on oceans and their part in global warming appear to contradict the published science. Gray believes that the increased atmospheric heat – which he calls a ‘small warming’ – is “...likely a result of the natural alterations in global ocean currents which are driven by ocean salinity variations." (BBC Interview 2000)
The Science
The problem with Gray’s argument is that unless more heat was being poured into the oceans, they would be obliged by the laws of physics to cool when heat was transferred to the atmosphere.
80% of the heat in the planet's ecosystem is stored in the oceans, and they have been getting consistently warmer over time (Ocean cooling: skeptic arguments drowned by data). There would also be other indicators e.g. sea levels, which would be static or go down by some small amount as a result of thermal contraction. There are no indicators of ocean heat driving temperature changes that are supported by the evidence. It should also be noted that Gray has never published, nor offered any proof, of these theories, so his views are purely speculative.
Claims that the warming of the planet is due to heat being released from the oceans into the atmosphere are not supported by any empirical evidence or peer-reviewed science.
Last updated on 24 October 2010 by gpwayne.
Thats very weird thinking. The transmission goes like this:
1. Increased solar activity leads to oceanic warming. Leads to more water vapour, leads to atmospheric warming.
2. Increased solar activity leads to less invasion of cosmic rays, leads to less cloud cover, leads to greater oceanic warming, leads to water vapour, leads to atmospheric warming.
3. Increased solar activity, leads to greater momentum in oceanic currents, leads to greater imbedded energy in the oceans via the Stefan-Boltzmann's law.
With regards to point 3. Were there some basic change to the "resistance to circulation". If some change in oceanic currents led to a better circulation or less resistance to circulation then you would expect the oceans to accrue more energy and that would eventually have the side effect of greater average global temperatures.
In keeping with this thread, you may be interested in a paper from Nature: AMO will stop warming until 2020. This seems to coincide with SSC24 as well. I added two links dealing with the AMO, PDO and ENSO cycles in Is Pacific Decadal Oscillation the Smoking Gun? as well as the ENSO related posts in It's volcanoes (or lack thereof)
about the cause of El Nino/La Nina.
which maps are you referring to (in relation to your statement about warming on ridge lines)?
Compare the charts of "hot spots" to a good map of the ocean floor such as Nat. Geo. maps. Also see post 115 in the volcano thread.
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In 2007 Roger Pielke, Sr. suggested that ocean heat should be used not just to monitor the energy imbalance in the climate system, but as a “litmus test” for falsifying the IPCC’s AGW hypothesis (Pielke, “A Litmus Test…”, climatesci.org, April 4, 2007). Dr. Pielke is a Senior Research Scientist in CIRES (Cooperative Institute for Research in Environmental Sciences), at the University of Colorado in Boulder, and Professor Emeritus of the Department of Atmospheric Science, Colorado State University, Fort Collins. One of the world’s foremost atmospheric scientists, he has published nearly 350 papers in peer-reviewed journals, 50 chapters in books, and co-edited 9 books.]
The Global Warming Hypothesis and Ocean Heat
I think that this was an excellent point.
Oceans are warming across the globe."
This is incorrect, although you might get away with saying they are warming on a six year average, for a little while anyway.
Cazenave et al 2008 concludes that the steric sea level has been falling since 2006.
The ARGO data shows that there has been a recent swift fall in ocean heat content globally. (Oct 2009 prelim data)
Further more, the quote provided by Quietman "the ocean, which must be the principal reservoir for excess energy”, clearly rules out any knowledge of a mechanism resulting in a net heat flux from atmosphere to ocean.
But unless such a mechanism is found and sufficiently supported by evidence a warming of the oceans seems far more likely to cause global warming than anthropogenic increase in green house gases.
There are various independent lines of empirical evidence that this is happening. A series of papers analysing different satellite data find less infrared radiation escaping to space. Similarly, a number of different papers find more infrared radiation returning to the Earth's surface. So we have a mechanism for warming the oceans and evidence that this mechanism is indeed at play.
For the record, I'm actually planning a post that specifically looks at the pattern of ocean warming and how it indicates human influence on climate - but just haven't had the time to write it yet.
Step 1: Chill beer.
Step 2: Pour beer into glass.
Step 3: Sip beer, noticimg its temperature.
Step 4: Wait three minutes.
Step 5: Go to Step 3.
For example it is quite obvious that one of the results will be an increase of evaporation which can result in a net cooling.
Then there is the question of penetration i. e. how far can infrared radiation penetrate the water to warm it. As some reports claim a warming of the oceans down to 700 meters this quite clearly can hardly be explained by exposure of the surface to increased infrared radiation.
Anyway I see the main weakness of this theory in the missing attempt to rule out alternative causes.
Tom Dayton: Your experiment needs some more elaboration.
1. How to make sure that the only source of heat comes from the atmosphere above as I doubt that a glass provides enough insulation for that.
2. How to sip some of that beer (assuming that to be an adequate measurement method) without inducing currents within the liquid which will scramble up and disturb the current heat distribution.
The key lies in the words "surface temperature" and regional variability, how much heat is available where we can measure it in various regions of the surface temperature network and different regions of ocean surface. Keenlyside predicted a regional cooling in the North Atlantic area caused by circulation changes in the North Atlantic ocean, sufficiently strong as to cause a change in the overall surface temperature trend, even as other areas of the globe continued to warm.
Behind all this is no change in the total amount of energy being retained on the planet, rather a change in distribution. Popular press treatments of this paper conveyed the impression that warming was going to stall or even that the Earth was going to cool, which is wrong in terms of energy being retained on Earth during the period covered by Keenlyside's prediction.
Richard Wood explains this in a commentary at Nature accompanying Keenlyside et al:
[Keenlyside's] starting point is the ocean. On a time scale of decades, this is where most of the ‘memory’ of the climate system for previous states resides. Anomalously warm or cool patches of ocean can be quite persistent, sometimes exchanging heat with the atmosphere only over several years. In addition, large ocean current systems can move phenomenal amounts of heat around the world, and are believed to vary from decade to decade.
Wood goes on, regarding the extent of the predicted cooling:
The authors use their model to predict that the MOC will weaken over the next decade, with a resultant cooling effect on climate around the North Atlantic. Such a cooling could temporarily offset the longer-term warming trend from increasing levels of greenhouse gases in the atmosphere. That emphasizes once again the need to consider climate variability and climate change together when making predictions over timescales of decades.
On a parenthetical note, it's fun when scientists bet money on validation. Some climate researchers found Keenlyside's analysis and forecast sufficiently debatable as to offer a bet on the outcome.
There's a useful article here from Woods Hole providing a general explanation. It's a bit old, but it provides lots of search terms for following things forward.
Are the Atlantic meridional overturning circulation and the Great Ocean Conveyor interelated?
Plus, why trust me when you can eliminate a layer of fallible human nature and go straight to researchers themselves?
Thus ends the article.
But if I am not mistaken the temperature of the water is one of the dominant factors determining the rate of evaporation (i. e. the warmer the water the higher the rate of evaporation). But more evaporation equates to more water vapour in the atmosphere (aka latent heat) which will result in warming the atmosphere. Else a lot of physics text books need rewriting.
In a previous post I complained about mentioning alternative explanations for rising ocean temperatures. I will give just three with the humble request to be shown how or where these are debunked.
1. Marine as any other life needs energy to build its biomass. By now we are next to successful clearing our oceans of it. In consequence that energy is not used for this purpose and heats the water instead.
2. There may be spots where the earth crust has grown thinner over time and therefore more of the earth's interior heat gets transferred to upper layers. As the earth's crust is thinnest below oceans this may heat the water above.
3. Not only are we clearing out next to all marine life from the oceans we are using them as garbage bins as well. I recall reports stating that all over the oceans probes were taken that revealed a higher content of plastics than phytoplankton. I think it is rather likely that these areas when hit by visible light will absorb more of it and in return emit more infrared radiation aka heat.
And to quote Christopher Hitchens, assertions without evidence can be dismissed without evidence.
As to warmer water leading to evaporation and more warming, well, that's absolutely true, one of the basic positive feedbacks to temperature change. That's well understood basic physics, and doesn't lead to a runaway situation, if that's what you're implying.
But more evaporation equates to more water vapour in the atmosphere (aka latent heat) which will result in warming the atmosphere.
This is incorrect, I believe. The amount of water vapour that the atmosphere can hold is determined only by the temperature of the atmosphere. Factors that increase only the rate of evaporation will simply increase the rate of condensation out as well. In the atmosphere that means clouds form faster and then more precipitation.
1. Marine as any other life needs energy to build its biomass. By now we are next to successful clearing our oceans of it. In consequence that energy is not used for this purpose and heats the water instead.
I would think the main route for marine life to obtain energy is photosynthesis and respiration. Indeed, given biochemistry, I would expect respiration inside marine animals to keep them at a higher temperature than the water (blubber in marine mammals would seem to corroborate this). Therefore I think denuding the oceans would most likely have a nett cooling effect.
2. There may be spots where the earth crust has grown thinner over time and therefore more of the earth's interior heat gets transferred to upper layers. As the earth's crust is thinnest below oceans this may heat the water above.
This is beyond my realm of expertise, but I would note that what is actually required is a nett thinning of the crust for the oceans to get warmer. "some spots" is not, of course, sufficient.
3. Not only are we clearing out next to all marine life from the oceans we are using them as garbage bins as well. I recall reports stating that all over the oceans probes were taken that revealed a higher content of plastics than phytoplankton. I think it is rather likely that these areas when hit by visible light will absorb more of it and in return emit more infrared radiation aka heat.
Phytoplankton photosynthesize (by definition) which is the absorption of visible light, I would imagine they are better at it than plastic, unless perhaps most of the plastic is black ...
Not by much. Here's what Douglass and Knox 2009 have to say about tectonic heating:
The geothermal contribution is constant [certainly over human time scales], but cannot be ignored because it contributes directly. The flux into the ocean and trenches averages 101 ± 2.2 mW/m2 and that into the land and shelves averages 65 ± 1.6 mW/m2 (globally averaged, 87 ± 2.0 mW/m2) --emphasis added
Compare to solar heat flux, same source: The mean solar flux S0 at the earth’s orbit is assumed to be 340 W/m2±1 W/m2 A sizable difference in favor of solar heat.
The history of the AGW hypothesis seems to have developed the other way round.
About water vapour: I just wanted to point out that the cited quote can't be correct as there is an established method of heat transfer from the ocean to the atmosphere while I still could not find any hint of significant heat transfer the other way round. By the way, so far the only explanation I encountered about AGW causing oceanic temperature rise was that the oceans are (due to their thermal capacity) the only available heat sink. That clearly qualifies as an assertion without evidence.
muoncounter, Thanks, this is the kind of reply I would have generally expected (but seemingly I'm asking too much).
Unfortunately the data that is referred to are from a paper published in 1993 and is therefore rather useless given the fact that reports about rising ocean temperatures state them to be most significant in the last decade.
Besides, due to the theme of this site you should have selected the alleged additional heat flux from anthropogenic
global warming as comparison.
You don't do science by hunting for and debunking all possible and dreamed of hypotheses (as that is an infinite set), which is what you seem to be asking for - you do it by following the evidence, learning what common events and generalizations can be made, and examining the evidence for and against them.
The history of the AGW hypothesis seems to have developed the other way round."
You must be reading a different history than the one I've seen.
When Arrhenius first proposed enhanced greenhouse warming from human CO2 emissions in 1896 a whole host of objections (CO2 absorption is saturated, water vapor absorption overlaps, oceans can absorb all the extra CO2, human emissions are too low, et cetera) were raised and the idea was dismissed. It is only as each of those, and many other, objections has been disproved over the subsequent decades that it has become clear that Arrhenius was correct.
The paper I cited was published in 2009. Do you think those authors knowingly used the 1993 data (which has been cited by 167 subsequent papers through 2010) without some consideration of whether or not they were still appropriate? More to the point, do you think the earth's geothermal heat flow into the oceans varies by a 3 orders of magnitude (we're talking watts vs. milliwatts) over the course of 17 years? Everybody would have noticed that!
Yes, the 'alleged' GHG forcing, as shown here still trumps this 0.087 W/m2 from geothermal 30 or times over. What was your point?
The logical consequence of this claim is that rising atmospheric temperatures (due to anthropogenic global warming) causes rising ocean temperatures.
There are two ways this could happen:
Either the warmer atmosphere actively warms the underlying oceanic waters or the energy transfer from the oceans to the atmosphere via evaporation (latent heat) is slowed down.
For the first possibility I have not seen any evidence presented so far while the second possibility directly contradicts the implied main positive feedback mechanism (more evaporation causing an increased green house effect of warming).
A simple lab experiment could be conducted to prove (or disprove) the possibility to increase water temperature via warmer air above. Create a water column of let's say of 10 m perfectly insulated at the sides and the bottom. Lower a strip with temperature sensors (equally spaced to measure the downward propagation of heat) into that column that is adjustable so that the first measurements will occur just below the water surface (to allow for evaporation losses) and expose the water surface to a (monitored and controlled) warmer layer of air. Now let's say we consider a rise in temperature of 0.05 C at 2 m below the water surface significant that then will be the end point of the experiment.
If the sensor indicating 2 m below surface hits the bottom of the container before that it should be considered a disprove.
Else you have a partial success and data (energy usage, propagation speed of heat etc.) to start calculations how these findings relate to the reported warming of the oceans.
I believe latent heat carries something like 78 W.m^2 averaged over the globe (higher over water, of course), while IR involves ~396 W/m^2 upward, and the atmosphere gives 324 W/m^2 downward, the sun 168 W/m^2. The IR exchanges and incoming sunlight are dominant.
Increased evaporation (as someone correctly pointed out) is really dependent upon increased air temperature, as increasing temperature increases the possible partial pressure of water in the air.
As to evaporation it seems you are seemingly mixing up possibility and reality. Warmer air can hold more water vapour therefore warmer air will lead to more evaporation. That seems to me the line of reasoning and it is a logical fallacy.
Let me explain with the case at hand, evaporation. It should be obvious that the conditions governing the process need to be in place where the process takes place. Now I think it is no deep secret that the bulk of evaporation takes place over tropical ocean during daytime (when sunshine warms air and water). Unfortunately the bulk of warming occurs at far higher latitudes and during the night. Therefore it is quite unlikely that evaporation will significantly increase. The correct conclusion that can be drawn is that higher atmospheric temperatures may influence (diminish) the conditions that govern condensation (and precipitation in consequence) which by the way gives a perfect explanation for the ice loss of alpine glaciers in permafrost regions.
Warmer air will hold more water vapor - the same relative humidity at different temperatures leads to different absolute humidities. So warmer air over water at an unchanged temperature will end up with more absolute humidity, more H2O in the air column, more greenhouse effect.
And warmer water can raise the relative humidity in the air above it, again raising the amount of H2O in the air column. So these effects interact.
Increasing H2O therefore acts as positive feedback upon CO2 driven global warming.
Second, about my argument on evaporation. Unfortunately you completely failed to show any evidence that at least one part of my argument is wrong. Therefore I will apply Mr. Hitchens advice to your comment, though I am unaware that he is considered some sort of authority on science theory.
In an earlier version of the paper Trenberth estimated 390, then corrected it based on surface temperature variations - +/- swings around average temperatures, due to the T^4 term in thermal radiation, means that a varying temperature surface will emit a bit more than an evenly warm surface.
The IR backradiation has also been directly measured, repeatedly and quantitatively, since the 1950's. (Stern, S.C., and F. Schwartzmann (1954) An Infrared Detector for Measurement of the Back Radiation from the Sky in J. Atmos. Sci., 11, 121-129. This documents early measurements of backradiation with a pyrgeometer).
As to water vapor, you should read the page on Water vapor is the most powerful greenhouse gas. That states the scientific case regarding water vapor feedback more clearly than I can in a few lines.
About water vapour. The article you mention states: the level of water vapour in the atmosphere is a function of temperature.
When I wrote about my argument against that notion (basically the same I gave in a previous post) concerning the wikipedia article on water vapour that part of the article got removed in response.
Stefan-Boltzmann´s law applies to bodies. All of them. They all emit energy if their temperature is above 0ºK.
What you said is like stating "Newton never said his laws applies to cars!".
You also didn't find any hint that SB only describes emissivity in a total vacuum. Have fun here.
Anyway I am still waiting for a reply on my main point that I outlined in detail at my post #26.
The oceans receive solar radiation and back IR, giving up energy via conduction/convection, evaporation, and IR (in increasing order of magnitude). The atmosphere is heated by conduction/convection, evaporation, solar and surface IR. At the top of the atmosphere all exchange is via EM, where the atmosphere is optically thin enough to actually radiate the IR to space.
I'm failing to see what your issue with ocean heating is. Perhaps you could restate your concern?
Boy, I don't follow this statement. If the oceans were feeding global warming they would have to be warmer than the atmosphere for heat transfer to occur. Heat flows from hotter to colder always whether it is conduction, convection or radiation. Since the oceans radiate very little it has to be conduction and convection. This is kind of like the beer illustration in reverse.
Problems in assessment of the ultraviolet penetration into natural waters from space-based measurements interestingly seems to disregard or at least down play the role of the atmosphere (CO2 and air) in the absorption of UV in the oceans. The ozone hole, aerosols, clouds and the nature of the ocean with it's life seem to be bigger drivers of the absorption of UV. UV is of course a big player in warming the oceans.
Hence, if the oceans were warming the atmosphere they would be cooling.
But this is NOT what is happening. It is not warm air that is warming the sea - it is increased radiation (sun + backradiation) that is warming the sea. Ie radiative heating not conductive heating. And in that setting, it is warm ocean that is warming the air, not the other way round.
... recent ocean warming ... has increased the humidity of the atmosphere, altered the atmospheric vertical motion and associated cloud fields, and perturbed the longwave and shortwave radiative fluxes at the continental surface.
This proposed mechanism doesn't seem to make any sense, but it does argue for strong positive water vapor feedback.
Dr. Trenberth's 2009 lament that: "The fact is that we can't account for the lack of warming at the moment and it is a travesty that we can't.. Our observing system is inadequate."
Note that Dr. Trenberth doesn't seem to countenance the possibility that the whole anthropogenic thesis - that the climate is driven by man-made industrial emissions - might be wrong. It is the absence of the real world to follow the models that is the alleged "travesty."
"Subsurface temperature trends in the better-sampled parts of the World Ocean are reported. Where there
are sufficient observations for this analysis, there is large spatial variability of 51-yr trends in the upper ocean, with some regions showing cooling in excess of 3°C,"
http://journals.ametsoc.org/doi/pdf/10.1175/JPO3005.1
A cooling ocean would falsify the validity of the AGW radiative forcing theory.
[DB] "Seems like the oceans aren't increasing in heat." and "A cooling ocean would falsify the validity of the AGW radiative forcing theory."
Except for a lack of evidence to support those assertions. Trenberth's most recent paper shows significant sequestering of OHC from the upper ocean into the deep ocean. Coupled with Hansen's aerosol forcings hypothesis, the global energy budget appears to likely close.
A refocus on science rather than unsubstantiated speculation would be of help to you.
And note the warming oceans down to 1500 metres:
First I am not supposing that the oceans are driving global warming but it hits me quite queer that a measured warming of the oceans is put up as proof for anthropogenic global warming over and over again.
Unless my understanding is completely screwed up AGW (climate change) is based on the fact that various gases (mostly CO2) emitted by our industrial society are heating up the atmosphere due to the so called greenhouse effect. So far so well?
Now I completely fail to understand what this has to do with rising oceanic temperature unless there is a physical process allowing for the atmosphere to heat up the ocean. Looking around I just found that on average ocean temperatures are higher compared to the atmosphere above which (according to the theory of thermodynamics) would not allow for such a process.
But this in turn leads tho the conclusion that AGW and rising ocean temperature are unrelated and the so are the effects of the latter. But of cause if you leave out all the effects of rising ocean temperature you loose a lot of the most scaring predictions of AGW.
Not quite. The GHGs reduce the amount of heat escaping into space. Over 90% of this heat takes up residence in the oceans.
We focus on the extra heat kicking around in the atmosphere because it matters more to us (to the first order at any rate). It's also easier to measure surface temperatures and we've been measuring them for a long time.
You need to think it through before you talk. If you phrase your statements as a question you will not look like someone who is not serious about answers.
The ocean loses heat to the atmosphere above it since it is warmer (as you point out). When the atmosphere warms, the ocean loses heat more slowly (according to the theory of thermodynamics as you referred to). When the ocean loses heat more slowly it warms. This is obvious to people who do not have an agenda to to discount the real problems caused by AGW.
Summary: the ocean loses heat more slowly to a warmer atmosphere so the ocean increases in temperature.