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.
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“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.