Dr. Roger Pielke Sr. writes:
News Article On The Earth’s Heat From Radioactive Decay
An intriguing news article has appeared by Charles Q. Choi titled
Radioactive decay fuels Earth’s inner fires
The article includes the text
“Extraordinary amount of heat remains from primordial days, scientists say
The researchers found the decay of radioactive isotopes uranium-238 and thorium-232 together contributed 20 trillion watts to the amount of heat Earth radiates into space, about six times as much power as the United States consumes. U.S. power consumption in 2005 averaged about 3.34 trillion watts.
As huge as this value is, it only represents about half of the total heat leaving the planet. The researchers suggest the remainder of the heat comes from the cooling of the Earth since its birth.”
To convert the estimate in the MSNBC news article to watts per meter squared, 20 trillion watts must be divided by the area of the Earth [5.1 x 10^14 meter squared] which yields a heat source of 0.039 watts per meter squared.
This is well less than the significant radiative forcings as estimated in figure SPM.2 in the 2007 IPCC WG1 report and, except for local effects where lava flows and volcanic eruptions are occuring , this heat is of minor climatic importance [the outgassing of sulphur dioxide and other chemicals and of ash, of course, are a different issue]. The heating of the interior and resulting effect on currents in the Earth’s mantle, however, are important in climate on very long time scales as this helps drive plate tectonics, such as continental drift.
“As huge as this value is, it only represents about half of the total heat leaving the planet.”
Leave it to MSNBC to forget about little details like the Sun.
Slightly OT: The lead story on ABC’s World News Tonight last night was the heat wave spreading through the middle of America. Not one mention of climate change, global warming, etc. Was this deliberate or accidental?
Wait did the article not say that 20 trillion watts was about half of the heat coming from the earth? So would that not make the 0.039 number printed lower that it really is?
Dr. Roger Pielke Sr.:
Sir, you are quite obviously wrong. I have it, on good authority (Al Gore), that the earth’s core is millions of degrees hotter than the 5000 to 7000 degrees Celsius used in your heat transfer calculations. GK
I have not yet had an opportunity to review this paper.
I have on a number of occasions postulated upon whether the deep ocean is heated by the Earth given that the average depth of the ocean is 4.3km (about 14,000ft) and at its deepest is about 11km deep (about 36,000 ft). If one were to remove the ocean altogether, surely these deep valleys would be very hot since they are nearer the core/mantle (think about Death Valley). As one knows, the geothermal gradiant is about 25 – 30deg C per Km. If this holds true on a universal basis, it would suggest that the sea bed should be about some 120 deg C warmer than the land at sea level.
Are not the oceans effectively lying upon a hot plate (the sea bed) which is running at a temperature of about 120 deg C higher than the land at sea level? Doesn’t this actually heat the deep ocean? This heat source would help explain deep ocean currents and may explain why the oceans would not freeze, even if there was no backradiation/GHG effect.
Is this heat source taken into account by the models?
No one has ever replied to my comments on thiis point before. I even put it to Willis when we were having an argument as to whether the oceans would freeze but for backradiation/GHGs but he never answered the point simply side stepping the issue.
I would be interested to hear some views.
This ‘newly discovered’ radio-active decay is only a tiny portion of the REAL Earth fission energy. More energy is ‘concealed’ as elemental compounds and as latent heat transfers at ocean vents. These processes are described in “Fossil Fuel is Nuclear Waste” and “Earth’s Missing Geothermal Flux” posted at http://www.FauxScienceSlayer.com
This KamLAND energy was discussed in “Motive Force for All Climate Change” posted at ClimateRealists.com May 14, 2009 and read into the U S Congressional Record. Some scientists have know about this force for a long time.
I wonder how much energy is (or was) stored in our planet from the initial collapse of the matter of the solar system, under gravitational attraction, to form Earth.
More or less than the stored radioactive potential? Any guesses anyone?
20 trillion watts only amounts to 0.03 Watts per sq. meter. Compare that to around 240 W m-2 absorbed by the sun.
Even if the geothermal heat flux were to suddenly double, we would never measure the temperature change.
The volcano image and the “20 trillion watts!!” made me think of..
http://www.zug.com/daily/journal/graphics/091010_streak_obama_02.jpg
Perhaps Josh could be inspired to pose Trenberth speaking of his missing heat in this way.
Hate to toot my own horn, but I have been saying for a long time the heat budget of the Earth is not understood enough to make the silly claim a few extra CO2 molecules in the air were the driving force behind climate change…..
I still think El Nino and El Nina are the product of undersea bursts of heat from the mid-plate rifts.
Richard Verney – It may be that no one is responding to your speculation because it is not plausible. Death Valley is not warm because it is closer to the Earth’s mantle. In all thy getting, get thee understanding.
I have recently read a couple of replies on Newsvine discussing stories on MSNBC where people make the claim that pumping oil out of the ground is heating the planet because the Earth uses the oil as a coolant. And one of them was claiming the core was getting hotter because of it instead of the surface getting hotter.
Joe Olson says:
July 21, 2011 at 8:15 am
This ‘newly discovered’ radio-active decay is only a tiny portion of the … energy.
Add to this the heating of the earth through tidal forces, not just on the oceans but on the earth itself, which flexes under the influence of the sun, moon, etc. This work will create heat within the earth.
carbon-based life form says:
July 21, 2011 at 8:45 am
Richard Verney – It may be that no one is responding to your speculation because it is not plausible. Death Valley is not warm because it is closer to the Earth’s mantle.
The deeper in the earth you dig, in general the hotter it gets. The crust is relatively thin over the oceans as compared to the continents. As well, the water from the oceans does not stop at the sea bed, it extends deep within the earth for an as yet unknown distance. The oceans are simply where the earth’s global water table is higher than the land. Water likely extends downwards under the oceans until it is turned to super critical steam at immense pressure, which will then vent upwards carrying heat back towards the ocean floor.
@richard Verney
No the ocean isn’t lying on a hot plate. The crust is thinner not absent and rocks are very good insulators while water is exceedingly good at conducting heat upwards by convection.
If there were no liquid ocean covering most of the planet it be one giant snowball which has happened in a few rare instances in deep time anyway. It’s all about surface albedo. The liquid ocean for all practical purposes is black and absorbs almost every watt of sunlight that falls on it. Rocks reflect about 15% of incident sunlight. Snow reflects about 90%. So as snow cover replaces bare rocks and liquid water there’s a point of no return, or at least a point where it requires many millions of years for volcanism to darken the surface with soot and build up greenhouse gases to the point where the snow begins to melt and expose lower albedo rocks and liquid water again in a rapidly accelerating melt. We are currently poised near the tipping point of a global freeze with the only things saving us from a snowball is that the sun is about 10% brighter now than in the very distant past and there’s continent covering one of the poles which limits the rate at which heat can leave the system.
Where internal heat has a more interesting effect is on Venus. The surface of Venus receives no sunlight at all because it’s all reflected away high in the atmosphere by deep, unbroken cloud cover. Yet the surface of Venus is hot enough to melt lead. That’s because the atmosphere at the surface is 80 bar and insulates the surface almost as good as the rocks in the crust. Internal heat, although no greater than earth’s internal heat, cannot easily escape through the Venusian atmosphere once it reaches the surface of the crust so even that small amount of internal heat of less than 100 milliwatts per square meter, builds up to a very high temperature in the thick surface atmosphere.
richard verney says:
July 21, 2011 at 8:11 am
“ . . . it would suggest that the sea bed should be about some 120 deg C warmer than the land at sea level.”
At my house this morning the air temperature is near 65 F degrees. The surface of the ground is the same. Water in the deep oceans* has a temperature between 0-3 degrees Celsius (32-37.5 degrees Fahrenheit). The sea bed (rock) at these deep levels will have almost the same temperature. Just as the air above my soil whisks away any heat arriving at the surface from deep within Earth before I can sense it, so too, does that nearly freezing water take away any heat arriving at the top of the sea floor. If there is a hot spot or spreading ridge with active volcanism then there is localized heat – quickly dissipated. Consider Hawaii. There is active volcanism there but its climate is determined from its location, not its geothermal gradient.
*
http://destinydeepseawater.com/ocean_temp_info.html
Roy Spencer says:
July 21, 2011 at 8:26 am
20 trillion watts only amounts to 0.03 Watts per sq. meter. Compare that to around 240 W m-2 absorbed by the sun. Even if the geothermal heat flux were to suddenly double, we would never measure the temperature change.
Are we that certain that the 30C or so extra warming of the earth as compared to what is calculated from the sun’s energy is due to GHG in the atmosphere? Is it possible that we are wrong somewhere in our assumptions about the relative importance of GHG?
Is it possible that we have overestimated the importance of GHG as compared to heat generated within the earth itself? I would imagine it is quite difficult to accurately measure the heat flux from the earth under the oceans flowing into the deep oceans, because the circulation of the oceans would confuse any measurements.
As the deep oceans warmed from the earth under, the water would tend to rise, carrying away the heat. While at the same time, cold water from the surface at the poles would sink to replace the warmed water. How much of this circulation is due to heating and how much is due to cooling, this seems to me a hard thing to take for certain, given our lack of measurements and understanding of the deep oceans. More people have been to the moon than to the bottom of the Marianas trench.
For example, we known that the deep ocean circulation is on the order of 1500 years, which corresponds very closely to the 1500 +- 500 year Bond cycle. Are we that certain that this cycle is driven by the sun? Is it not possible that the heat source for this circulation is the heat within the earth itself? If so, then it could be that the heat of the earth is under estimated in its influence on climate?
Following up on Dr Roy’s comment that the 20 teraWatts is still only 30 mW/ m^2; it is however a net OUTWARD flow of heat from the solid earth, which would imply a Temperature gradient that is negative, so that Temperature falls with increasing radius.
That to me suggests, that the solar energy input from the sun, NEVER makes it to the average solid earth (which is under some ocean); but is recycled to the atmosphere, and subsequently to outer space, by oceanic processes, primarily convective transport of heat.
Evidently sunlight makes it to the extreme depth of 3,000 ft, albeit very little, and the resulting expansion due to solar heating results in a net upward buoyancy and a resultant upward convection, which brings the solar energy back to the surface. Of course this happens over long timescales, and includes upwellings, and other local disturbances, as well as simple buoyancy.
Is it any wonder that the results of solar processes, which may affect deeply penetrating solar energy fluxes, may not show up for centuries, and that the return of atmospheric emitted LWIR radiation toward the surface, is somewhat inconsequential as far as warming the ocean. Remember that the presumed pseudo gray body from the atmosphere hasan equivalent BB source Temperature of around 288 K; but somewhere in the 250 to 350 K range.
carbon-based life form says:
July 21, 2011 at 8:45 am
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Death Valley was just a throw away comment in parenthesis. Of course, I understand that Death Valley is warm because of its geological features and its location. I accept that it is not very much below sea level and hence depth in itself plays little role.
The question is, how much warmer would Death Valley be if its floor lay say 8,000 m below sea level? In answering this question, 2 factors would come into play. First, the temperature increase due to the extra 8km of atmosphere. Second, the temperature increase due to the land lying closer to the mantle/core. Consider whether if one were to walk bare foot on the ground, would one burn ones feet? I consider the answer to be firmly YES.
You are probably aware that in deep mines, temperatures can approach 70 degC. This heat must predominantly come from the fact that the bottom of the mine is nearer to the mantle/core and these deep mines are only a fraction of the depth of the ocean floor.
As I said, if this applies universally, it would suggest that if the oceans were removed, the floor of the ocean would on average be around 100 degC and one would be unable to walk bare foot on the foor of the oceans. I am not suggesting that with the ocean in place, if one were to put ones hand on the sea bed, one would burn it. I am suggesting that this would not happen because the warmth that would otherwise exist is being absorbed and carried away by the deep iocean itself.
Consider the vast area of the oceans. This could all add up to a lot of heat which is only slowly radiating to space because the ocean inhibit its radiation and they act as a hige heat reservoir only gently giving up their heat.
In summary, I am mooting that the oceans are being heated not simply by solar energy from above (DWLWIR due to its wavelength cannot sufficiently penetrate the oceans) but additionally from heat energy from the mantle/core below. .
Just how do these models factor in the Earth’s core heat? I have been told that the temperature is in the neighborhood of 5,500 of degrees C that at about 12 kilometers the temperature is about 200 degrees C, and that at 4 kilometers (the TauTona Mine) the temperature is over 30 degrees C. There really is not that much insulation. In northern Vermont (10 miles from Canada) we had a water line from a spring head that ran over 1500 feet at a depth of less than 3 feet and NEVER froze up in the winter! Any mechanical engineer will tell you the surface of the earth has to be approximately the same temperature as the surrounding air.
Supposedly the thickness of the Earth’s crust, floating on this massive ball of molten rock and metal, would be less than the thickness of an egg shell if the Earth were reduced to that size. Well where does this heat go? It has to radiate outward and must be warming the earth. Place a few ounces of molten solder in a Styrofoam (or one that will take the heat) cup and see if you can pick it up. Additionally, there are numerous vents on the floor of the ocean (many ,many more than on dry land), especially along the ridge line at the center of the oceans, spewing massive (and I mean humongous) amounts of water heated to 350-400 degrees C. That is quite a bit of thermal energy being dumped into the ocean. And scientists didn’t even realize they were there when all of this AGW hype started. How do they factor in all of this heating that bypasses any insulating properties of the crust? How have the geologists taken into account these phenomenon into the actions that caused the end of the ice age?
Having lived on a farm I know that it only takes a very small amount of spring water (50 Degrees F) from a spring under a lake to prevent the formation of ice on the top of the lake – with very low air temperatures. And, if there is no spring, then all it takes is a small air pump, like you would use in a larger home aquarium, to keep a water opening on the lake. Could the weight of the ice on the contents have caused the formation of more hydrothermal vents which in turn caused the end of the ice age?
Surely you have been under a “radiant heater” at a loading dock or in a service garage. The air temperature can be well below zero, but you feel perfectly warm in shirt sleeves, no coat needed. The radiant heat is not heating the air it is heating the solid objects. So what is all of this bunk about the IR capture of CO2 multiplying the heating effect? In my mind it would block the IR heating effect, like the filters you place on the thermal guard windows, not enhance it. I think some models need remodeled.
Not to be a units Nazi but I am sick and tired of people misusing Watts as heat. A Watt is a unit of heat rate, Joule/sec. A Joule is a unit of heat or more specific, energy. Every time I read an article stating something to the effect of this “wind farm generated XXX megawatts which powered XXX homes” it just drive me crazy. Tell us how man MW-hrs it generated last year, that will tell us something that means something!
Dave Springer says:
July 21, 2011 at 9:25 am
@richard Verney
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Dave you miss my point.
I am not looking at whether the oceans absorb sunlight/solar energy (of course they do) and I am not looking at what effect there would be if there were no oceans (obviously there would be a drastic effect and the world would be a very different place). I am merley postulating upon whether the oceans are being heated not only from above (by solar eneragy) but also from below (by heat left over from the planets formation and radioactive decay). AND if the oceans are additionally being heated from below, is this source of energy set out in the computer models?
I am basically pondering on the points which are addressed by ferd berple in his second post at
July 21, 2011 at 9:47 am
????this heat is of minor climatic importance???Yeah!!! Only,If you ignore the 3 million +++ SUBMARINE Volcanic and black smokers that warm the Ocean
John F. Hultquist says:
July 21, 2011 at 9:31 am
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John
I am not doubting that the surface of the ground in your garden is at (or nearly at) the same temperature as the air. What I am saying is that if you were to go out into your garden and dig a pit some 4.5kn deep (ie, approxiately the average depth of the ocean), you would find the bottom of the pit to be very warm. If you were to put your hand in the soil at that depth, you would burn your hand.
As others have commented, it is well known that the soil is a lot warmer below ground and this is why water pipes have to be buried at specified depths (depending upon geographical location) to prevent freezing. The same phenomena should appty to the ocean floor.
The bottom of the sea bed is much nearer the mantle/core than where we live on top of the land, and for this reason it is probable that the sea bed would naturally be very warm but for the fact that it is covered by the ocean which absorbs the heat and carries it away (with ocean currents and circulation). I do niot know how much energy is being absorbed, but it is probably far more than is being put into the ocean via undersea volcanoes and ocean vents since although the heat is not extreme (may be circa 100degC) it is being applied over the entire surface area of the sea bed.. .
So if I read that article correctly, of the energy leaving the earth, 0.039 W/m^2 is due to radioactive decay and a similar amount is from residual heat from the earth’s formation. For a total of 0.078 W/m^2 (?), but as Roy Spencer points out, this is insignificant compared to the 240 W/m^2 that has to be radiated away to balance out energy from incoming sunlight. I don’t think I’ve ever seen internal heat from the earth shown on any of those spiffy “Earth’s Energy Budget” diagrams. So, interesting for Geology; for Climatology, not so much.
But here’s a question, and forgive me if this is naive but I am curious so if anyone can enlighten me I’ll do my best to be appreciative. Neither of these heat sources – radioactive decay and cooling from a molten state – are constant over time. Nor have they changed linearly over time (half-life is exponential by definition, the exponent being 1/2, correct?). So, over geologic time, might they have been significant in the past? Maybe even in the ballpark of contributing to the Early Faint Sun paradox?
Just how weird a coincidence would that be, the sun picking up the slack at just the rate needed to balance out the Earth’s reduction in internal heating? (Anthropic principle anyone?) Or maybe it’s just a demonstration that whatever feedbacks are in play have dealt with much larger changes in the past and no tipping point so far (other than that pesky ice age thing anyway).
Thoughts?
Such a forcing is perhaps part of determining the secular energy budget of the Earth, a very small part, but for climate change it is not likely even an insignificant concern, as it probably is going down maybe one percent in a million years, so for our purposes roughly constant. of course, on a geological timescale, the slow cooling down of the Earth’s interior may be important. It probably is still much smaller than the long term brightening of the sun which was about 80% of current brightness about 2.5 billion years ago (can anyone with more solar physics background check my numbers here? I think I might be off somewhat.) a forcing substantial enough that it should have induced a very cold Earth, but we have extensive evidence of liquid water from that period and no evidence for glaciation. This “faint young sun paradox” is an indication that the climate has remained within narrow bounds even with wildly different “boundary conditions” from forcings orders of magnitude larger than this, and even an order of magnitude larger than the forcing from a doubling of CO2.
10 TerraWatts or 0.03 W/M^2.
Makes me wonder how much that value was 4 billion years ago.
A brighter burning early Sun gave way to a much lower output Sun of today.
The mass and density of the oceans does form a time barrier to outright radiation, much like the density and mass of the Sun keeps nuclear output from reaching the surface for 1 million years.
So, in order for CO2 and greenhouse gases to significantly slow the cooling off of the Earth, the total density AND mass of the atmosphere has to increase significantly. All it would take to upset this balance is for the Sun to drop its output…which it has done over billions of years. But, in reality, the Earth is not in inertial thermal balance, but leaks slowly and irrevocably over great expanses of time.
The ultimate path of planetary cooling is moderated by the great mass of the Sun (which moderates the Solar Fusion output) but still ends up looking like a frayed rope. Both are seeking a lower energy state, and the final outcome is cold, dead bodies floating in space.
Relax, it’s going to take billions of years.
Life on Earth has existed for 80% of the Earths history. Nothing we can do will heat it up beyond that total range of temperature, though we could launch enough Nukes to waste all life except the most basic.
????this heat is of minor climatic importance???
REPEAT> Yeah!!! Only,If you ignore the 3 million +++ SUBMARINE Volcanic and black smokers that warm the Ocean AND THERE HAS BEEN A 400% INCREASE IN ACTIVITY TO BOOT.
This IS where and why there is the current rise of C02 just like before every deep ice age.
The proof is in the timing of the now due 65million year cycle,in fact WE ARE ENTERING A multiple cycle called a Converging Harmonic Cycle.
We are in the same spiral arm and crossing the thin magnetic disc around the Galactic Equator,and people don’t seem to have worked out yet it seems, why the Co2 is rising is RIGHT ON TIME for the 65million year cycle to be ALL natural.Well 97%? maybe.
TAIWAN increased seismicity
http://sites.google.com/site/jacquesangelier/InstrumentalEarthquakes.jpg
http://www.earth.webecs.co.uk/
Figure 2.7 Seismic data acquired on the Norwegian continental shelf in the period 1962 – 2000
http://www.npd.no/engelsk/npetrres/petres2001/images/figurer/2-7.gif
Take a look at these USGS earthquake numbers. Go here for more details. You have to wonder how anyone could justify that earthquakes aren’t increasing. Their strengths certainly are.
http://standeyo.com/NEWS/08_Earth_Changes/080510.diz.bogus.story.html
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http://www.poetpatriot.com/timeline/tmlndisvolcanos.htm
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Why doesn’t the deep ocean freeze up? My understanding was that the enormous amounts of pressure applied to non-compressable water keeps that water from freezing.
These are geologists, and they’re talking about heat leaving the molten part of the planet. What is happening on the surface is irrelevant, other than how it messes up their rock samples. Don’t compare these numbers to the total surface/atmospheric radiation budget, as they’re clearly only dealing with the geologic heat component.
The current numbers on part of Wikipedia are “Mean heat flow is 65 mW/m2 over continental crust and 101 mW/m2 over oceanic crust.[12]”. http://en.wikipedia.org/wiki/Geothermal_gradient
@ richard verney @ Roy Spencer @ Dave Springer @ John F. Hultquist
Think about this:
When the Earth was warm in paleoclimatological past – Plate tectonic activity was high.
When the Earth was cool in paleoclimatological past – Plate tectonic activity is low. And that is today where Milankovitch cycles play a very large role in our climate causing the huge Pleistocene temperature oscillations which were not there 40 million years ago or more. I am speaking here of Long-Term climate change. Not the short term one. There were/are always shortterm fluctuations in climate. Even 50 million years ago.
Where are most of these oceanic ridges and subduction zones situated which cause increased or decreased tectonic activity? Yes underwater in the Deep Ocean.
Is Deep Ocean Temperature solely controlled by Atmospheric Temperature? Or could Geothermal Heat Exchange with Deep Oceanic water be a serious factor to consider?
Science underestimates the influence of Geothermal Heat Exchange with the Deep Ocean.
A warmer Deep Ocean means a warmer climate. http://www.essc.psu.edu/essc_web/seminars/spring2006/jan18/Zachosetal.pdf (Fig. 2)
-This hypothesis could easily explain the existence of liquid water during the Faint Young Sun Paradox. How warm (geothermally) was Young Earth anyway?
-It could easily explain why Snowball Earth melted. (Decreased tectonic activity causing the Earth to freeze over – Increased tectonic activity causing ocean temperature to rise and melt the ice)
-It could also easily explain why Hyperthermals recover so beautifully. (This is somewhat more complicated to explain in a few sentences)
Three problems science is struggling on for years, even decades.
http://www.youtube.com/watch?v=PZjPGdXMMso Watch the difference in speed of the plates and heat exchange with the air in this case. Earth tectonic plates move almost identical. The physics is practically the same. One can even witness flood basalt events at 0:05, 0:12, 0:18, 0:22, 0:25.
The difference here is: Timescale.
We know so little about the geological history of the Earth.
This hypothesis could be a beautiful contender for replacing the CO2 theory.
So, essentially, the US energy consumption is fart all in space and hell for warming the earth’s climate as well.
That’s good to know, since it means that Australia’s energy consumption is not even a whiff of a sneaker fart in space and hell for warming the earth’s climate.
I strongly suspect that the atmospheric lapse rate would pretty much govern the temperature of the ocean floor if the water were “magically” removed without changing the albedo of the earth as a whole. Since the lapse rate is ~ 6.5 C/km and people here are using ~ 4.5 km as the depth, the temperature would be ~ 30 C warmer than at current sea level.
The fact that the sea floor is closer to the core would be only a minor effect, I strongly suspect — much the same way that a valley is warmer than a mountain top because of the lapse rate, not because of the distance from the center. Or conversely, the temperature 1 mile below Denver (ie at sea level) will be much hotter than in Los Angeles, even though both are the same distance from the center. The geographical gradient must almost certainly be steeper under the ocean than under the land. (in fact, this scenario would decrease the difference, since we would be warming the ocean floor considerably.)
richard verney says: July 21, 2011 at 10:48 am
But this is a false analogy. If you took that pit and sloped the sides out to make it a typical valley or ocean basin 20+ km across, the bottom of the valley would still be warm, but at an atmospheric gradient of ~ 6.5 C/km, not the geological gradient of ~ 25 C/km (assuming the number quoted above it correct).
Barry Day says: July 21, 2011 at 10:34 am
If you check the numbers, the area of the ocean is about 300 million km^2. so there is one smoker for every 10 km^2 = 10 million m^2. Even if the smokers average a megawatt of heat, then that is still only 0.1 W/m^2. Compared to 240 W/m^2 from the sun, this 0.1 W/m^2 of thermal energy is indeed “minor”.
P.S. This agrees remarkably well with wikipedia “Heat flows constantly from its sources within the Earth to the surface. Total heat loss from the earth is 44.2 TW (4.42 × 1013 watts).[12] Mean heat flow is 65 mW/m2 over continental crust and 101 mW/m2 over oceanic crust.[12] ”
http://en.wikipedia.org/wiki/Geothermal_gradient
When you think that one of the best insulator, a vacuum insulated panel, has a R value of at best 8.8 K m^2/W, using the 0.039 W/m^2 value and that of the emperature of the upper mantle, we get a R-Value for the crust of about 24,950 K m^2/W.
Interesting article, thanks. Also interesting to compare the Earth’s heat with the net heat rate radiated by a human body. It’s on the order of 100 watts per square meter (according to
http://en.wikipedia.org/wiki/Black_body#Human_body_emission)
So, only about a half a trillion watts total.
😐
The issue of intense heat sources within the Earth’s core was not understood in the 19th century. Thus, Lord Kelvin dismissed Darwin’s theories by showing, using calculations of heat radiation from the earth, that not enough time had been available for evolution by natural selection. Darwin was appalled, and he had no conclusive answer, though he knew he was right.
visit: http://iamyouasheisme.wordpress.com/2010/01/12/quantitative-deep-freeze/
Barry Day says:
July 21, 2011 at 10:34 am
Figure 2.7 Seismic data acquired on the Norwegian continental shelf in the period 1962 – 2000
Unfortunately your Norwegian seismic data consists of a measure of the number of kilometers seismic survey vessels have travelled collecting seismic data for oil exploration – nothing to do with earthquakes.
NPD stands for Norwegian Petroleum Directorate – http://www.npd.no
Title: 20 trillion watts is not even Trenberth’s missing heat
20 trillion watts isn’t even close to the rating of the speakers in the car the kid down the street drives around. ;o)
Seriously, I was wondering what is the possible error for that number; 2X? 3X? 10X? +/- 2 trillion?
http://www.scientificamerican.com/blog/post.cfm?id=nuclear-fission-confirmed-as-source-2011-07-18
Misquoted and misreported by Scientific American.
@ richard verney.
You are ignoring the atmosphere and the oceans, both of which are great at heat transfer. Dig two pits 8 km deep, one at the equator and one at the south pole. Are they both the same temperature (and very hot) at the bottom? No. Neither will reach your 126o temp either.
The mine analogy also doesn’t work. Go underground 2 km and the temperature is not 50-60o but more like 35o. This is because they pump down cool air. Take away the atmosphere and the oceans and eliminate convection and then yes, your point could be reconsidered.
G. Karst – I did not calculate the heating rate; I just converted their analyzed heat flux to a per meter squared unit. The Earth’s crust, of course, results in a buffering between the surface and the higher heat in the interior.
ferd berple says:
July 21, 2011 at 9:24 am
“…Water likely extends downwards under the oceans until it is turned to super critical steam at immense pressure, which will then vent upwards carrying heat back towards the ocean floor…”
Close, but not steam… and not really water either. At a hydrostatic depth of about 2.25 km, water is above it’s supercritical point of 22.064 MPa (3200 PSIA). 2.25 km is about 22.1 MPa. It won’t matter how much you heat it, it won’t go into a gas state.
In rock, at this depth and pressure, it tends to do other interesting things… like lowering the melting point of the rock that it’s entrained in… or joining the chemical structure such as in amphiboles and other hydrous reactions.
From Global Tectonics 3rd ed (Kearey, Klepeis and Vine):
The penetration of this convection is not known, but it is possible that it is crust-wide. It is thought that hydrothermal circulation of seawater in the crust beneath ocean ridges transports about 25% of the global heat loss, and is clearly a major factor in the Earth’s thermal budget.
Baa Humbug says:
July 21, 2011 at 11:25 am
“Why doesn’t the deep ocean freeze up?”
For the same reason as the water in a lake, pond, or reservoir of sufficient depth (for its location). Water at a certain temperature (~3.98 C) reaches maximum density and sinks. Beyond that temperature, that is, as the water continues to lose heat, the water becomes (again) less dense and more buoyant and will eventually freeze at the surface. It does so at the water-atmosphere boundary because the air (above) is colder then the water and the heat flow is from warmer to colder.
As the comments indicate, the ocean floor temperature will be above that of the adjacent water temperature and again heat will flow from the rock (warm) to the water (cold). There is no reason for the water to freeze at sufficient depth.
Water is the strangest substance the average person ever encounters. The list of its oddities is long –density with temperature can be found here:
http://en.wikipedia.org/wiki/Water_(properties)#Density_of_water_and_ice
I think the heat in the Earth comes more from the gravitational dough-hooking the Moon and Sun provide than anything to do with radioactive decay. The lack of general understanding of physics most scientists expose is quite astounding.
Sorry, add me to the Oops list.
http://www.micom.net/oops/
In my last comment I left out the degree sign on the temperature. It should be ~3.98° C.
I have to use ASCII Code to get the symbol. For ‘degree’ it is Alt 0176.
http://www.ascii-code.com/
enjoying the discussion of earth’s heat which has always seemed, to me, counterintuitively ignored in the climate world. i’m always struck when i hear that “absorbed solar radiation is 10,000 times as great as the heat emitted into the atmosphere via the earth’s thermal gradient”, and therefore the earth’s heat content of 10 to 31st power of joules can be completely ignored.
sounds like AGW propagandists cherry-picking sound bites.
it seems that it would be equally fair to say that, at night, the heat emitted to the atmosphere by the earth’s crust is MILLIONS (or, billions for that matter) of times greater than any heat received from the sun – since, at night, there is NO heat received from the sun.
at night, when there is no incoming solar energy, the stored and emitted heat coming from the earth is the only heat entering the atmosphere for 1/2 the globe. the heck with 240 watts per square meter at night – it doesn’t happen.
accepting that the convention for earth’s geothermal gradient heat is expressed in watts per meter squared terms, it seems to me that consideration needs to be given to the fact that the earth’s crust (dirt, sand, water, rock, etc) is FAR more dense than the air above it – on the order of 800-2000 times as dense – ranging from the density of water to, say, granite.
therefore, assuming an adjacent cubic foot of air and cubic foot of crust would tend to be the same temperature at any place on earth, the fact is that the cubic foot of earth under the air would contain 800 to 2000 TIMES the amount of heat. in other words, 1 square foot of earth’s crust, 1 foot deep, must hold more heat than a mile of air above it. why this isn’t significant is beyond me, especially considering that the earth is constantly being heated from underneath, whereas the air is only being heated by the sun when the sun shines – and the sun’s rays wax and wane all day long fading to zero at nighttime.
the trapped chilean coal miners were hot because of that thermal gradient, not from any effect of the sun at all.
and so, it seems to me anyway, that the heat content of the earth must be the dog that wags the climate’s tail rather the heat content of our thin layer of atmosphere being the tail that wags the dog.
Come to think of it: the input power is equal to that of the the converted energy output plus waste energy output. Both the converted energy output and the waste energy output is less than the inputed power but is equal to the the inputed power.
Since a part of the inputed power is converted to good and proper use, like apples and oranges, the output energy of the US power consumption is then, of course, less than the stated power consumption and the energy to heat conversion of that power consumption is really just bugger all in that great scheme of things.
So why would anyone be as derange a communist as to tax, by the hundreds of billions, the US power consumption if it is less ‘an a sneaker of a whiff of a farts problem in space and hell?
John F. Hultquist says:
July 21, 2011 at 2:39 pm
Sorry, add me to the Oops list.
http://www.micom.net/oops/
“In my last comment I left out the degree sign on the temperature. It should be ~3.98° C.
I have to use ASCII Code to get the symbol. For ‘degree’ it is Alt 0176.
http://www.ascii-code.com/”
° Thanks, John. I just had to try it.° This is a very interesting discussion but I am not sure whom to believe! I do know SSam is correct re water at high pressure.
prjindigo says: J uly 21, 2011 at 2:29 pm
An interesting hypothesis. Please provide calculations of the magnitude of this heating effect. Or a link to textbooks or scientific articles that quantify the tidal heating of the earth. Enlighten us on the proper physics.
Or enlighten us as to the mistakes in the article attributing half the heating to radioactive decay as evidenced by detection of neutrinos.
Lichanos-Kelvin actually had a contemporary critic, and although I have often read it said (and repeated myself) that Kelvin’s error was no fault of his own, as he couldn’t have known about radioactive decay. Except that Kelvin made another error, namely he modeled the mantle as rigid, not fluid, and thus no convection within it. His critic was John Perry, and as early as 1895 he got an estimate in the right order of magnitude, just from accounting for that:
http://www.geosociety.org/gsatoday/archive/17/1/pdf/i1052-5173-17-1-4.pdf
John:
Unlike fresh water, sea water (3.5% salts) does not have a temperature of maximum density above its freezing point. Its coefficient of thermal expansion is almost zero at these near-freezing temperatures, but never goes negative, as fresh water does below about 4C.
A while back I suggested that taking the crustal temperature around the world with 50′ boreholes would be a much better way to measure how warm the Earth is.
I will use this opportunity to put in a shameless plug for geothermal heating. We have had a closed loop system for about ten years and it is one of the best decisions we ever made. We have missed the rise in nat gas and fuel oil prices. They make a lot of sense if your electricity is relatively cheap…..say under 12 cents per kwH.
2 trillion sounds like a big number but it is 192 thousand trillion times less than the Sun puts out.
Without the Sun and the gravitational energy of the atmosphere, the 0.03 watts/m2 would translate into a temperature of -258C.
Paul Irwin says:
July 21, 2011 at 3:11 pm
Paul, you lost me with the “at night when there is no incoming solar energy”. For the earth there is always incoming solar energy 24 hours a day. This energy is going to be redistributed by the atmosphere and the oceans. Convection by air and water has a far greater effect than conduction from the ground into the air or water.
Drill a borehole 2 km deep and it will equilibrate rapidly to the ground temperature – no chance for convection. Sink a mine shaft and eventually it too will equilibrate without ventilation. That is why the Chilean miners got hot. But so what? Expose that ground to the air or water, circulate it and the wall rock will equilibrate to the air or water temperature very quickly. So absorbed thermal radiation from the sun is much greater than thermal gradient energy from the earth.
Geothermal energy is great but the amount of energy it produces is pretty small – yes enough to heat or cool a house but not enough to meet the energy needs of a nation.
These gravitational flexing(s) would certainly affect the crack crevice expulsion and draw. It would also introduce rhythmic patterns to thermal convection waves. Isn’t it wonderful, to “hear” stimulating discussion. GK
prjindigo says: J uly 21, 2011 at 2:29 pm
I think the heat in the Earth comes more from the gravitational dough-hooking the Moon and Sun provide than anything to do with radioactive decay. The lack of general understanding of physics most scientists expose is quite astounding.
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In principle, the gravitational pull of the moon is likely to cause warming, it is just a question of scale.
Coniser IO, which is the most geological active body in the solar system This is due to tidal heating caused by gravitaional pull. Of course, IO is subject to significant gravitaional force from Jupiter on the one hand, and the other Galilean moons on the other hand. The Earth is not being so squeezed but the fact that the moon can distort the oceans gives an indication of what it is doing/trying to do the core. This obviously must generate some heat.
Baa Humbug says:
July 21, 2011 at 11:25 am
Why doesn’t the deep ocean freeze up? My understanding was that the enormous amounts of pressure applied to non-compressable water keeps that water from freezing.
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No, surely you’ve heard… it hasn’t frozen because the ‘globe’ has been ‘warming’. Keep up!
The atmosphere ain’t nothing but an insulation blanket – keeping heat both out and in – the AGW folks like to push the wild-eyed hypothesis that the atmosphere governs all, but it is just ‘there’ and moves heat from the oceans inland… last to the relatively extreme heart of the continents.
If you get really bored you can dive into the geotechnical whiplash curve and find that the earth’s subsurface energy gradient is primary, the polar axis seasonal tilt secondary, and atmospherics tertiary.
The solar activity and cosmic ray crowd may bump the atmospherics to forth or fifth place though.
AGW is driven by atmospheric proponents alone… basic thermo would push that factor out as trivial as temp change in a hydro plant and they do not like it.
I think the point is that the interior of the earth is still not well understood. It seems that most of the guess at the sources of the heat and the amount of heat are still quite immature. It is acknowledged that there are four sources of heat inside the planet:
– heat from the initial planetary formation
– heat from internal friction as heavy elements sink into the core
– radioactive decay (and remember that recent idea that cosmic rays affected that rate?)
– friction from the tidal effects of the moon and sun working on the fabric of the planet
None of these have been precisely quantified and this recent article is part of that ongoing science I guess. I would guess that all of these create time varying heat fluxes at the surface but who knows what the timescales or amplitutudes of variations are? It is immature science still.
It has always seemed strange to me that the heat budget diagrams either don’t show this source or show it as being trivial when it is poorly measured and poorly understood.
What I have wondered for years is how much of the Earth’s interior heat is not from radioactive decay, but from nuclear fission.
This one talks about Natural Fission Reactors at 17 locations in a rich ore deposit in Gabon.
http://www.scientificamerican.com/blog/post.cfm?id=natures-nuclear-reactors-the-two-bi-2011-07-13
I remember reading about in is Sci Am almost 20 years ago (though I thought it was South Africa).
The Gabon reactors were concentrated by aquias solution, then moderated by ground water the influx of which was balanced by evaporation when the reactor reached a critical assembly.
I’ve grown up hearing the Earth has an iron core, or an iron-nickel core to explain the Earth Magnetic fields. I don’t doubt iron and nickel are present, but I think over the course of 4 billion years, a great many highly dense metals have migrated toward the core, including uranium.
Is it possible that in the inner and lower part of the outer core, the conditions are ripe for a low energy, barely critical, breeder reactor? It would be kept in balance by changes in temperature; it wouldn’t take much delta-T with an assembly several hundred miles in diameter.
What about reactor poisons? These might prevent the whole thing from working. Lead would sink too, but is slightly less dense than U. Would it stratify with a richer U preferentially under a lead rich layer?
I had hopes from the referenced articles that talked about neutrino flux that some discussion about fission as different from decay would be brought forth. But the 07-18 link from Dan seems quite confused about this point “Over the billions of years of Earth’s existence, the radioactive isotopes have been splitting, releasing energy as well as these antineutrinos—just like in a man-made nuclear reactor. …. how much of Earth’s heat results from this radioactive decay.
The large proportion of radioactive decay IS nuclear fission. Those Gabon locations date from an era when the constant apparently varied, not by the voodoo you read about.
The issue I have with your theory, Rasey, is simply that there is no gravity at the center of the effective Earth-Moon mass, heavy objects could NOT be forced into a tiny little space and compressed there. The null gravity location is off-center from the Earth’s rotational axis.
There is no radioactive material which would survive several billion years of active half-life in a heated (accelerated) environment.
richard verney says:
July 21, 2011 at 6:57 pm
prjindigo says: J uly 21, 2011 at 2:29 pm
I think the heat in the Earth comes more from the gravitational dough-hooking the Moon and Sun provide than anything to do with radioactive decay. The lack of general understanding of physics most scientists expose is quite astounding.
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In principle, the gravitational pull of the moon is likely to cause warming, it is just a question of scale.
Con[sider] IO, which is the most geological active body in the solar system This is due to tidal heating caused by gravitational pull. Of course, IO is subject to significant gravitational force from Jupiter on the one hand, and the other Galilean moons on the other hand. The Earth is not being so squeezed but the fact that the moon can distort the oceans gives an indication of what it is doing/trying to do the core. This obviously must generate some heat.
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Sorry for the long quote. So you agree that the agitation should generate heat; especially considering the inverse event horizon which occurs at the center-of-gravitational-mass of the Earth-Moon system. (Io is a bad example since you can actually induction heat sulfur once above a threshold temperature, much like using microwaves to continue melting already heated glass.) It simply becomes a question of how much heat combined with induction heating by magnetic systems and how much remission of heat loss the added solar energy adds to the total environment act as an insulating system to maintain the temperatures necessary for the orbital mechanics to continue generating heat. Such a concept begs the question of whether vulcanism is caused by plate tectonics or by stored up heat within the system requiring release. Does the earth crack open and spew magma and lava simply because the system must equalize? Has anyone actually ASKED these questions before?
Curt says:
July 21, 2011 at 4:08 pm
“Unlike fresh water, sea water (3.5% salts) does not have a temperature of maximum density above its freezing point.”
Thanks Curt, I guess I missed that chapter. And, I’ve never worked with salt water. This just adds to my belief that water is a very odd substance.
Tim Folkerts says:
July 21, 2011 at 3:25 pm
prjindigo says: J uly 21, 2011 at 2:29 pm
I think the heat in the Earth comes more from the gravitational dough-hooking the Moon and Sun provide than anything to do with radioactive decay. The lack of general understanding of physics most scientists expose is quite astounding.
An interesting hypothesis. Please provide calculations of the magnitude of this heating effect. Or a link to textbooks or scientific articles that quantify the tidal heating of the earth. Enlighten us on the proper physics.
Or enlighten us as to the mistakes in the article attributing half the heating to radioactive decay as evidenced by detection of neutrinos.
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When I bend #12 copper wire it gets hot. I can thaw steaks with compression and flexing.
Hot reactors generate more fission, is the fission driving the heat or is the heat driving the fission?
I think you’ll find that adding several thousand degrees to any random mass of heavy metals will generate a great deal more fission than would otherwise normally occur if they were laying around the lab. I don’t appreciate soapbox trolling and I was discussing the discussion.
Using neutrino detection in the article’s way sounds much like trying to determine which fans in a full stadium are Ford owners based only on the sounds they make. It strikes me as an attempt to generate a data set simply to meld into whatever shape is wanted to support a pre-determined hypothesis. Politicians change the data to support hypothesis, scientists just raise their hands and say “its just a lot of noise”.
My posting on this site could easily statistically lead you to conclude to which I am more akin.
I think that this confirms what we have already discussed about geothermal activity that it is a small part of the energy buget of the earth .It has been mentioned that as we get closer to the molten part of the mantle then the temperature rises also the molten part of the mantle can rise closer to the surface and the surface will get warmer.The local warming caused by volcanic activity could cause pressure changes in the atmosphere which determine the direction winds flow the wind direction is important in things like the ENSO,AO and NAO and other weather patterns.
20 million watts is an awful lot of blog posts, I’ll never be off the damn computer….! 🙁
Follow Up…
If you get really bored you can dive into the “geotechnical whiplash curve ”
Sorry to say, if you were really really bored and ‘binged’ that, you unfortunately had few relevant hits,
the first hit being from our very own .gov “DRAFT Conceptual Engineering/Socioeconomic Impact Study”, first of just seven references being Anderson & Ladanyi 1994, “An Introduction to Frozen Ground Engineering”. I do not have that on my shelf but do have a precursor by Andersland and Anders (1978) and have had numerous papers in journals by all three. Have ready access to cite #4, have on the shelf #5, and sold #7(but should not have).
The whiplash curve has already been referenced. It is verifiable everywhere on earth. If you want to really really believe that a big ball of fire millions of miles over your head has more impact on the temperature of your feet than a big ball of molten rock a few miles below, well, everybody needs to believe in a little bit of magic.
@prjindigo – You are correct that at the exact center of the earth, there is no gravitational pull. But if you do the math, for a sphere of uniform density, gravitational acceleration falls off linearly with r as you descend into the sphere. (Mass falls off with r^3, but Gravitational acceleration increases with 1/r^2)
But the earth is not of uniform density. The core is higher density than the mantle. So at a radius of 2000 mi (1/2 Earth’s radius) you probably have 0.55 G. Gravity still works in the outer core.
As for the plate tectonics question, Yes, people have asked it. John Fredrick Dewey is a structural geologist who is/was a leader in tectonic geophysics. When everyone was saying late 80’s?) mantle convection drove the plates, he believed the viscosity of the mantle was a couple of orders too high for this to be the driver. His observation was that oceanic crust and the mafic roots of sialic crust were more dense than the upper mantle, creating an unstable system where the crust wants to overturn. The overturning of solid plates on a lava lake is the same physics, but a trillion times faster.
Part of his proof/argument was how the Indian plate subducted under the asian plate. The Tethian oceanic leading edge of the Indian plate dove under the Asian, pulling the rest of the indian plate North as the tongue sank. A few million years ago, that diving tongue broke off. Freed from that descending weight, the rest of the crust, including the southern portion of the asian plate, rebounded creating the Himalayan chain. Dewey sad this was a good argument explaining how the Himalayas are higher than they should be isostatically if they had a typical mafic root system.
@H.R. RE: amount of error in the calculation.
Always good to bring up uncertainty.
There is another assumption they have made: the neutrino flux they are measuring today is related to the heat flow we are measuring today. The problem? Neutrinos will be detected almost instantly after they were created. But the heat flow out of the core will take a ?million? years.
One of my favorite bargain book finds was “End in Fire” about the SN1987A supernova. Toward the end of the book they described what that Supernova would look like view from within its solar system. First of all, any planet inside the orbit of Saturn would have been destroyed earlier phases the star’s death. But suppose an intelligent race survived on a planet at Neptune’s distance. At the instant of the SN collapse and detonation, a cloud of neutrinos is generated. Unhindered by the mass of the star, they escape immediatly. As inactive as neutrinos are, there are so many of them that those poor souls on Neptune, 2 billion miles away, will get a lethal dose of ionizing radiation and be quite “incapacitated” when the SN photons rip through the star’s surface eight hours later.
(Sorry for the off track)
Baa Humbug:
How could water pressure be increased if water was not compressible?
Actually it is about four times as compressible, or elastic if you like, as steel.
SteveP says:
July 21, 2011 at 10:55 am
So if I read that article correctly, of the energy leaving the earth, 0.039 W/m^2 is due to radioactive decay and a similar amount is from residual heat from the earth’s formation. For a total of 0.078 W/m^2 (?), but as Roy Spencer points out, this is insignificant compared to the 240 W/m^2 that has to be radiated away to balance out energy from incoming sunlight. I don’t think I’ve ever seen internal heat from the earth shown on any of those spiffy “Earth’s Energy Budget” diagrams. So, interesting for Geology; for Climatology, not so much.
When that heat is radiated away, it leaves as long-wave IR. Consequently, if CO2 impedes reradiated solar energy from immediately radiating into space, it also would trap this energy as well. What I am really astonished at is the “newly discovered” bit. In geology back before plate tectonics was even taught, it was well known that granite contained enough radioactive material, decaying in sufficient quantities, and granite was a poor enough conductor, that over time masses of deeply buried granite could heat themselves to the point of melting. Physical geology classes were occasionally required to calculate this for themselves.
But here’s a question, and forgive me if this is naive but I am curious so if anyone can enlighten me I’ll do my best to be appreciative. Neither of these heat sources – radioactive decay and cooling from a molten state – are constant over time. Nor have they changed linearly over time (half-life is exponential by definition, the exponent being 1/2, correct?). So, over geologic time, might they have been significant in the past? Maybe even in the ballpark of contributing to the Early Faint Sun paradox?
They were indeed more significant in the past than now. See:
http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor
IIRC, the difference is not nearly enough to overcome a 20% short fall from the sun. In fact, if you look into Snowball Earth:
http://en.wikipedia.org/wiki/Snowball_Earth
it would appear that during the Proterozoic there seem to have been several episodes of planet-wide or near-planet-wide “ice-ball” states, possibly with ice clear to the equator. The sun would indeed have been cooler, but radioactivity clearly wasn’t picking up the slack.
Just how weird a coincidence would that be, the sun picking up the slack at just the rate needed to balance out the Earth’s reduction in internal heating? …
See previous.
And right you were.
I’ve always wondered about something. Would it make sense to place on the moon (the side always facing us), a sensor (or perhaps 3 to eliminate any error between them) that measures whatever can be measured from 200,000+ miles away in a constant orbit (albeit receding a few mm a year). Whereas satellites require altitude adjustments (among other problems), lunar observation would effectively be measuring the same exact line around the Earth forever. Changes would have to show up here and this would be as good as a planetary average as might be possible.
Tim Folkerts says:
July 21, 2011 at 11:56 am
Barry Day says: July 21, 2011 at 10:34 am
?????this heat is of minor climatic importance???Yeah!!! Only,If you ignore the 3 million +++ SUBMARINE Volcanic and black smokers that warm the Ocean
If you check the numbers, the area of the ocean is about 300 million km^2. so there is one smoker for every 10 km^2 = 10 million m^2. Even if the smokers average a megawatt of heat, then that is still only 0.1 W/m^2. Compared to 240 W/m^2 from the sun, this 0.1 W/m^2 of thermal energy is indeed “minor”.
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Tim, What happens when the Ocean current travels same direction as the plate boundaries and the heated water gets continually reheated time and time again.Wouldn’t that make your equations meaning less?There would be a localized strip of heated water alongside a landmass which would most certainly NOT be “minor”.!!!
@ Steve from Rockwood
“Geothermal energy is great but the amount of energy it produces is pretty small – yes enough to heat or cool a house but not enough to meet the energy needs of a nation.”
Wouldn’t it depend on the nation? According to the Wikipedia article below Iceland gets about 70% of its electricity from hydropower and the rest from geothermal energy. However, since it has large untapped reserves of both it would presumably be feasible for Iceland to rely entirely on geothermal energy for electricity production, not that there would be any point in abandoning hydroelectric power.
http://en.wikipedia.org/wiki/Renewable_energy_in_Iceland
Roy
I am happy I can still take out my CRC Handbook, c.r. 1971, and calculate that the earth radiates .082 watts per square meter. So not much has changed in 40 years…
@blade
> I’ve always wondered about something. Would it make sense to place on the moon …,
> a sensor … that measures whatever can be measured from 200,000+ miles away …
Satellite-born sensors provide the same capability. The diurnal variance from the Earth’s surface would greatly exceed any wobbles in the orbits (for which the data can be normalized).
What about sensing the Moon’s “heat” from Earth? Turns out this is mostly reflected IR from the Sun. Samuel Langley was the first to measure this IR radiation, back in the 1880’s[1], using a rock-salt prism to refract the ‘dark rays’ (as they were called then) into bands. He invented a gadget called a ‘bolometer’ to measure the heat in each part of the spectrum. Very impressive accomplishment, in light of the fact that he did this without any ‘modern’ electronics. Vacuum tube amplifiers weren’t invented until decades later.
Not all of the IR reaches the ground, of course. Some of it is absorbed by the Earth’s atmosphere by water vapor and other gases. Arrhenius used Langley’s lunar data as a basis to illustrate this phenomenon in his well-known paper [2] on CO2 absorption.
[1] Langley, “The Temperature of the Moon”, Memoirs of the National Academy of Sciences, vol iv, pg 193, 1890.
[2] Arrhenius, “On the Influence of Carbonic Acid in the Air upon the Temperature of the Ground”, http://www.rsc.org/images/Arrhenius1896_tcm18-173546.pdf, 1894.
@Roy.
Iceland is the exception that proves the rule. If you live on the mid-Atlantic ridge then yes, you are good for geothermal and major volcanic activity. Otherwise, no. The sun generates so much more energy than the earth’s thermal gradient and yet solar panels aren’t powering the world either. The energy in a liter of gasoline is really amazing and it won’t be easily replaced any time soon.
Steve
They forgot Potassium 40! There is actually very little Uranium left but the real heat producers are Thorium and Potassium because there is so much of them.
@prjindigo
July 21, 2011 at 9:46 pm
“[…]
Using neutrino detection in the article’s way sounds much like trying to determine which fans in a full stadium are Ford owners based only on the sounds they make. It strikes me as an attempt to generate a data set simply to meld into whatever shape is wanted to support a pre-determined hypothesis. Politicians change the data to support hypothesis, scientists just raise their hands and say “its just a lot of noise”.
My posting on this site could easily statistically lead you to conclude to which I am more akin.”
You drive a Ford? ;o)
I didn’t get what you were after when you mentioned “doughhook” in your first post. That term conjured up the wrong mental image for me and it took a few comments by others to get me on the right track.
Mechanically generated heat can be significant. I particularly liked your example of bending #12 copper wire. I work with tube benders and it brought to mind what happens when we bend a 90 degree angle with a 150mm CL radius in a piece of 48.6mm OD x 5mm Wall steel tube: enough heat is generated that one cannot grab the tube at the bend for several minutes afterwards. It always startles new bender operators when they first handle a bent piece.
I hadn’t thought about gravitational contributions to the earth’s heat budget. It’s not discussed much. Good point and I thank you very much.
richard verney says:
July 21, 2011 at 8:11 am
No, the ~25 degrees C geothermal gradient is from surface, not from mean sea level. So thats either the land surface or the sea bed. In the oceans the geothermal gradient is a bit higher because the crust is thinner but is mainly depends on the tectonics and type of rocks.
Barry Day says: July 22, 2011 at 12:49 am
Tim, What happens when the Ocean current travels same direction as the plate boundaries and the heated water gets continually reheated time and time again.Wouldn’t that make your equations meaning less?There would be a localized strip of heated water alongside a landmass which would most certainly NOT be “minor”.!!!
I find that equations are are rarely meaningless. 🙂
A global average is a global average. If one subset of the ocean water gets extra thermal energy, then that would mean other parts would get less thermal energy. That would not change the fact that 0.1 W/m^2 is “minor” compared to 240 W/m^2.
I agree that where that energy surfaces will make some difference. If a concentrated dose surfaces in one spot, then there will be local warming effects. But then the rest of the globe would get less warming.
Another issue is the amount of change. The various radiative forcings are on the order of 1 W/m^s. Unless the change in geothermal energy is ~ 1 W/m^2, its affect on climate change would be expected to be minor.
Yes, thermal effects of tidal forces on the earth have been studied.
Even if this is off a bit, this ~ 4 trillion watts is considerably less than the 20 trillion watts from radioactive decay, which is less than the total geothermal energy, which is much less than the solar energy.
prjindigo says: July 21, 2011 at 9:24 pm
There is no radioactive material which would survive several billion years of active half-life in a heated (accelerated) environment.
Temperature has no noticeable affect on decay rates. U-238 has a half life of 4.5 billion year — which by coincidence is the age of the earth, so 1/2 the U-238 that the earth started with is still here.
Again, the amount of heat (or energy) in watts (J/s)? That’s like amount of water in a tank in l/s. Or gasoline.
Anyway, the geothermal flux could easily be underestimated. Think of all the undersea volcanoes and vents.
“The December 12, 2005, issue of National Geographic News carried a story about a hydrothermal megaplume in the Indian Ocean that is almost 1 mile long and is thought to have the energy equivalent of 100,000 MW. The story went on to estimate the thermal output of all the known vents in the world at about 17,000,000 MW—about the same as current worldwide power generating capacity. Other major vents are known to be located off the coasts of the U.S., China, Japan, Korea, and South America, and in the Mediterranean Sea and Dead Sea. And there remain tens of thousands of miles of ocean ridges yet to be explored.”
http://www.powermag.com/issues/features/Tapping-seafloor-volcanic-vents_128_p3.html
Regarding energy balance, the averaged net heat flux at TOA is averaged insulation minus averaged Earth’s outgoing radiation:
Etoa = Einsol – Eout
At the lower system boundary (~10 m under the surface/sea floor), the averaged net heat flux is the geothermal flux:
Esurface = Egth
The change in internal energy of the system (accounting only for the heat fluxes) is:
dU = Egth + Etoa (input positive sign)
Assuming dU = 0 (averaged over periods with no significant trend in internal energy):
Etoa = -Egth
The average heat flux at TOA (over periods with no significant trend in internal energy of the system) is negative (heat loss) and is equal in magnitude the average geothermal flux.
ferd berple says:
July 21, 2011 at 9:47 am
“Are we that certain that the 30C or so extra warming of the earth as compared to what is calculated from the sun’s energy is due to GHG in the atmosphere?”
No. GHGs have very little effect over the ocean because the ocean doesn’t absorb long wave infrared. Infrared shined on the surface of a body of water merely raises the evaporation rate and water temperature is unchanged. Conversely visible light is almost completely absorbed by a body of water warming it to some depth. The energy from visible light absorption cannot escape the way it entered (radiatively) because water is opaque to infrared. It largely escapes by evaporation and before the deeper sun-warmed water can evaporate it must somehow reach the surface. The ocean is responsible for most of the greenhouse heating because, just like greenhouse gases, it is tranparent to visible light but opaque to infrared. The GHG effect is confined to land which limits its potential to raise global average temperature. The so called “missing heat” is not missing. It never made it into the ocean in the first place. It was rejected at the ocean surface through increased evaporation rate. The water cycle speeds up and you get more cooling from clouds and rain. The entrained energy is invisibly lifted from the surface in latent heat of vaporization and transported to the cloud deck where it is released and at that altitude the path of least radiative resistance is upwards as the denser layer of greenhouse gases are now below it and make it more difficult for downwelling infrared from the cloud deck to make it back to the surface.
Nuke says:
Slightly OT: The lead story on ABC’s World News Tonight last night was the heat wave spreading through the middle of America. Not one mention of climate change, global warming, etc. Was this deliberate or accidental?
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CBC Toronto interviewed a senior climatologist from Environment Canada who also avoided any mention at all of ‘global warming’ or ‘climate change’. Immediately afterwards a woman was interviewed who was obviously well prepared to state very clearly that the current heat wave is indeed the result of climate change, and later that it was becoming easier to be able to attribute this type of event to climate change which we know is induced by Man. The contradictions (it is/it could be/it is becoming easier/maybe/surely/almost proving/detectable) was not lost on me. It was nearly a word for word repetition of a paragraph I have read elsewhere.
The importance for me was the lack of alarm from Environment Canada who have slavishly spoken the party line thus far. Perhaps the hammering the warmists took for claiming the Moscow heat wave last year was caused by climate change, not a stalling high, sunk in. Expect specious, weasling, contradictory claims in the coming weeks.
Interestingly the number of deaths atttributed to the heat (22) is far lower than the cold wave in the UK this year.
Sure would be nice if we could harness all this heat for energy.
I did a science course with the Open University in the seventies in which I found out that the Earths mantle heats up by pressure the mantle heats up with the extra pressure with depth until it melts and then with greater depth and pressure it becomes solid again.This reason for heating of the mantle is not mentioned here.
@ SteveE says: July 22, 2011 at 5:30 am
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The oceanic crust is very different to the continental (land) crust. The oceanic crust is very much less thick (circa 7-10km in thickness) than the continental crust (circa 25 to 70 km in thickness). There are diifferences in density and latent heat capacity.
There is probably some data for temperature gradient obtained from oil wells drilled in the sea bed, however, these are situated on the continental shelves and are no doubt not representative of conditions that would be encountered if we were to drill in deep oceanic crust, ie., if we were to make a bore hole in the sea bed lying at say 4.5km depth. I envisage that temperature gradients in such crust would be significantly different but I have seen no data and as far as I know, man has never drilled there (but I stand to be corrected on that).
My point is not what geothermal energy is available in the depths of oceanic crust compared with that found at depth in continental crust. The point I am mooting (and I have no firm views on it), is whether if the seas were to be drained, ignoring the atmosphere and adiabatic lapse and ignoring convection. would the land temperature at the very deepest valleys of the oceans be warmer than the land temperature at the top of Everest? After all, at the foot of the deepest oceanic valleys, the distance to the warmer parts of the mantle is significantly less (say 7 to 10km compared to 70 to 100km). logic dictates that the nearer you are the mantle, the less impedience there is to heat being conducted/radiated away from the core and isn’t this what drilling boreholes on land bears out. Put another way, would I be warmer standing at the foot of the deepest oceanic valley than if I was standing on top of Everest?
If I would be warmer standing at the foot of the deepest oceanic valley than when standing on top of Everest, I am mooting the possibility that this heat source may not have been properly accounted fr in the models since it is additional to that produced by volcanic outgasing. I doubt that it would be large (at least not in comparison to the energy received from the sun) but when one is only talking about changes caused by approximately 2 or 3 w per sq m, even relatively modest factors could be significant contibutors.
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Yeah, but this is exactly what I am worried about.
I’m also thinking that no bird except those at a Lagrange point are truly reliable as the inevitable decay needs retasking and corrections, this human intervention step makes the data less than reliable, at least to me.
We’ve got this stable platform, the moon, sitting up there. I look at it and think, heck, we can get great photos and measurements of it from here, through our thick atmosphere. The Earth is even larger in the sky from the moon, there is almost no atmosphere, it is only a second ot two away in real-time comm, it is tidal locked and we know every little thing about its orbit. It seems the only problem would be lack of shielding from solar radiation and micrometeorites (both problems exist with satellites anyway).
My feeling is a consequence of the current state of human nature and science itself these days. When I hear that someone needs to adjust data to compensate for something peculiar to a satellite, I immediately lose trust. And considering that NASA employs people like Hansen, I know that agenda driven scientists *do* exist. Means, motive and opportunity.
I simply do not trust them any longer. Thus my idea. Plant sensors up there that cannot be tampered with and let the raw data speak for itself.
@Lichanos, Andrew
I just read War of the Worlds while on holiday, which was written by HG Wells in 1897. It gives an interesting insight into the state of astro / geophysical knowledge at the time. Basically both the planets and the sun were considered to possess only residual, primordial heat, and were thus steadily cooling. There was indeed no conception of a heat source within either, such as as then unknown nuclear processes (although Roentgen must have been discovering radioactivity around that time). Thus Mars was cold due to its greater age than earth, and in the past had been warmer and more habitable. The freezing Martians thus envied our warmer Earth and hence the invasion of London.
Wells considered Mars older than earth, contrary to current ideas of the genesis of the solar system which gives all planets more or less the same age.
richard verney says:
July 22, 2011 at 11:52 am
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That has been studied over a decade ago, while I was at uni studying geology:
http://www-odp.tamu.edu/publications/heatflow/ODPReprt.pdf
Page 15 average sea floor temp of 4.2 degrees C, page 19 shows data coverage. Think you can rest assured that’s all pretty pretty well covered.
An additional couple of sources for earths budget sure to cause debate.
1: the global electrical circuit, telluric currents, etc.
2: Modulation of earths magnetic field by external fields, and the inductive kickback or inductive heating that occur to earths “dynamo” molten rotating core.
Blade says: July 21, 2011 at 11:14 pm
I’ve always wondered about something. Would it make sense to place on the moon (the side always facing us), a sensor (or perhaps 3 to eliminate any error between them) that measures whatever can be measured from 200,000+ miles away in a constant orbit (albeit receding a few mm a year).
There is certainly some sense in this suggestion. One challenge i see is the long period of the orbit. With low-earth orbits, you get around the earth every 1.5 hours, so you can get frequent measurements of the spots under the orbit (which would be the whole earth for polar orbits). For Geosynchronous orbits, you get a continuous look at one part of earth.
But from the moon, you get a view that switches from the day to the night side once every 4 weeks or so. For some measurements that is would work quite well, since the earth spin under the sensors once per day. For temperature measurements, this would be problematic. You could measure the mid-day temperature of a location for a week; then measure the the dusk temperature for a week; then the night temperature for a week, then the dawn temperature for a week. It would be very difficult to get a global average temperature this way.
@SteveE says: July 23, 2011 at 7:19 am
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Thanks fir the paper. Interesting read. I note that the study found the seafloor temperature as high as18.7 deg C in some places. Unfortunately without sight of the files referred to in the paper, it is not possible to consider the situation and distribution of seafloor temperatures.
If you do have the files referred to in the paper, I would very much you posting a pdf of them.
thanks again,
Actually, since Trenberth’s missing heat never existed, 20 trillion watts is slightly smaller in climate modelling terms.
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richard verney says:
July 23, 2011 at 1:17 pm
Google ocean drill program, their website has quite a lot of data. The higher temps are most likely drilled on hot spots like Hawaii and Iceland or spreading ridges.
phlogiston says:
July 23, 2011 at 6:45 am
“I just read War of the Worlds while on holiday, which was written by HG Wells in 1897. It gives an interesting insight into the state of astro / geophysical knowledge at the time. Basically both the planets and the sun were considered to possess only residual, primordial heat, and were thus steadily cooling.”
Sure. I’m working from memory but as I recall it was Lord Kelvin about that time, or sometime between Charles Darwin publishing of Origin of Species and the turn of the century, who’d worked out the age of the earth at 100 million years by way of calculating how long it would take heat of formation to dissipate enough to reach current temperature. Back then the earth at 100 million years old was both religious and scientific heresy where the religionists pegged the age in the thousands of years using bible references and where science of the time (mostly through geology) held it to much older than 100my. Kelvin’s estimate was too short a period of time for Darwinian evolution and too long for bible literalists.
History of science can be fascinating reading and very enlightening.
@richard Verney
You have to take into account both heat sources and heat sinks. The earth’s surface is primarily warmed by the sun during the day and cooled by the deep cold of the empty cosmos which is only 3 degrees K above absolute zero. There is very little daytime warming at the top of Mt.Everest because it is covered in snow which reflects better than 90% of incident sunlight and has little atmosphere between it and the cold of outer space to buffer it. If the top of Mt. Everest could somehow be made dark it would be hot enough to boil water by mid-day much like the surface of the moon which heats up quite rapidly to black-body equilibrium temperature of about 120C not long after sunrise.
The moon is a natural laboratory for comparison to earth. It is made up of the same basic material as the earth but it has no hot mantle and no atmosphere. You can learn a lot about it by following links I’ve left in comments:
http://www.google.com/search?hl=&q=springer+regolith+site%3Awattsupwiththat.com&sourceid=navclient-ff&rlz=1B3GGGL_enUS290US290&ie=UTF-8
@ Dave Springer
Thanks, indeed as Lichanos commented Darwin was taken aback by Kelvin’s calculation; however he stuck to his guns and was eventually proved right.
It makes you wonder if current climate science will look a century from now similarly naive, lacking one or more key insights without which real understanding and analysis are impossible. From what direction will these insights come?
@Dave Springer says:July 24, 2011 at 4:04 am
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Dave, whillst I appreciate your comments, you completely fail to grasp the point that I am trying to consider.
I am trying to ascertain what would be the poistion if for one moment the sun was switched off, the oceans sucked dry, the atmoshphere removed and Earth was a barren planet much like Mars but with a hot active core as possessed by the Earth. Leaving aside the obvious consequences of not having the solar input, would the temperature of the rock at the top of Everest be as hot as the rock which at the deepest valley of the oceans? In other words, is the hot core trying to heat the deep oceans.
SteveE provided an interesting paper in which the survey found the average sea bottom sediment to be 4.2degC. The average deep ocean temperature is about 2deg C (may be a little more). If the average sea sediment temperature all over the planet is truly 4.2degC, it would appear that that the ocean crust is constantly trying to heat the deep ocean. This constant heating be additional to heat via hydrothermic venting.
Dave
I don’t think that much can be learnt from the moon.
You cannot compare a water world with a barren rock. The oceans, and the three phases of water are the key to climate on Earth. It is the oceans and water that drives the Earth’s climate.
richard verney says:
July 25, 2011 at 7:28 am
Just a quick follow up, the temperature of the water at the bottom of the Mariana Trench was measured at 2.455C (figure 4) @ 11197db, however the temperature minimum was reached at 4700db with a temperature of 1.455C. The reason for the increase in temperature with depth is the result of adiabatic compression, where by a fluid increases in temperature is it is compressed. I think this demonstrates that the temperature of the mantle is not really contributing to the heating of the deep oceans as you suggest.
The local tectonics would have an effect such as on a hotspot or rift, however pure depth wouldn’t, as there are some many more factors that have a much greater influence.
http://www.terrapub.co.jp/journals/JO/pdf/6103/61030447.pdf