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Chiloe
Trad climber
Lee, NH
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Is this something climate scientists talk about?
Geothermal heat is something all kinds of scientists talk about, geoscientists especially, and many of them also do or read climate research. So the answer to your question is (1) yes, many scientists have thought about it, recognizing that (2) the upward transfer of interior Earth heat to the surface is quite small compared with solar effects, and (3) near as anyone can tell, at a global level this flow is about constant on human time scales, so (4) as a result of (2) and (3) geothermal heat does not help to understand either the internal variability or forced changes we observe in Earth's climate. Although it does make a small contribution to keeping the surface warmer than it would be on a cold ball of rock like the Moon. If the sun went out tomorrow, that small amount would be no help.
Earth's geothermal gradient does have some more interesting climate dimensions, such as: (1) practical -- geothermal heat can be a renewable, low-pollution source of energy in several ways; (2) basic science -- borehole temperature readings help to reconstruct past surface temperatures by measuring temperatures at different depths, and calculating how those depart from the strict geothermal gradient we should see if surface temperatures had been constant. A surface temperature signal might thus be detecting (though increasingly weak, attenuated and smeared-out) down some hundreds of meters.
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raymond phule
climber
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Jammer, to me it sounds like you would except a large difference in temperature response for a house that his heated by the sun if a mouse live in the basement and radiate some heat compared to the the same house without the mouse.
I don't have much knowledge about this but the scale of things really seems to indicate that the possibly effect is very small.
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raymond phule
climber
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The presence of the internal heat is what allows the solar radiation to have any significant surface warming effect at all. Otherwise it would all just get sucked into the earth.
Interesting comment... So a large rock don't get warmer if it located at a sunny place?
My guess is that you completely miss the dynamics of heat transfer through a medium.
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raymond phule
climber
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I don't know if I dispute it or not because I really don't understand what you try to say.
I neither understand why my house example were wrong.
The heat transfer from the center of the earth to the ground is very small. The temperature of the ground in a sun less world would be much less than it is with a sun. Just take the temperature of the ground at night or winter.
I have no idea why the temperature of the core would do any difference when it is not the core that do the main heating of the ground and atmosphere.
To me it just seems to be a system like a house or rock with a very small heat source at its center being in connection with a much stronger outside heat source.
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Chiloe
Trad climber
Lee, NH
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On a clouds-have-silver-lining note, writing my last comment inspired me to learn a bit more about borehole temperature reconstructions. Here are two graphs (20,000-0 ybp at top, 1,000-0 ybp below) of Huang et al.'s (2008) global reconstruction. There's that darn hockey stick, again.
Abstract
We present a suite of new 20,000 year reconstructions that integrate three types of geothermal information: a global database of terrestrial heat flux measurements, another database of temperature versus depth observations, and the 20th century instrumental record of temperature, all referenced to the 1961–1990 mean of the instrumental record. These reconstructions show the warming from the last glacial maximum, the occurrence of a mid-Holocene warm episode, a Medieval Warm Period (MWP), a Little Ice Age (LIA), and the rapid warming of the 20th century. The reconstructions show the temperatures of the mid-Holocene warm episode some 1–2 K above the reference level, the maximum of the MWP at or slightly below the reference level, the minimum of the LIA about 1 K below the reference level, and end-of-20th century temperatures about 0.5 K above the reference level.
By "reference level" they mean the anomaly base period 1961-1990.
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rick sumner
Trad climber
reno, nevada/ wasilla alaska
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Usokin (I believe if my memory is correct) has a very long paper on the state of understanding of solar processes. Refer to that TLP. Im not even going to hazard a guess. All I know is that there has been a number of solar cycles identified from the average eleven year schwab, through the Seuss, Devries, and to the approx thousand year Eddy cycle. During these longer cycles there is large variations in the proportion of the makeup of solar radiation and smaller, although prolonged, periods of total radiation varying by 2wm2 at one astronomical unit (the average of earths orbital distance). In about 2004-2005 solar scientists began noting a weakening of the major solar indices that is predicted to continue and grow even weaker over the next few schwab cycles. The makeup of the radiation reaching earth has changed and weakened, also the suns magnetic field which allows more atmospheric penetration of ionizing cosmic rays. I would say we are seeing a migration of the west pacific warm pool to the north pacific, attracted by the upwelling cold waters of the negative phase of the PDO. My question is what physical mechanisms would allow for this. I don't see you guys claiming there is a dense cloud of CO2 that radically increased downwelling IR over this vast region, not yet anyway. So what is causing the sea surface temps to spike here.
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Ed Hartouni
Trad climber
Livermore, CA
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the total energy coming to the surface of the Earth per unit time from the sun is:
P = (πR²) (1-A) S
where R is the radius of the Earth, A the albedo and S the "solar constant"
take the internal energy per unit time to be
I = (4πR²) C
where we'll take C to be the +0.06 W/m^2 of the heat flow from the Earth's interior.
The Earth radiates:
r = (4πR²) ε σ T⁴
where ε the emissivity, σ the Stefan-Boltzman constant (=5.67E-08 W/m^2/K^4) and T the temperature of the surface...
the total input is then set to be equal to the radiated output:
(πR²) (1-A) S + (4πR²) C = (4πR²) ε σ T⁴
which we can rewrite as:
(1-A) S/4 + C = ε σ T⁴
the solar constant (which we were debating up above) is 1360 W/m^2 so we can put all these things in:
[(1 - 0.3)*1360/4 + 0.06 ]W/m^2 = 1. * 5.67E-08 W/m^2/K^4 T⁴
(238 + 0.06) W/m^2 = 5.67E-08 W/m^2/K^4 T⁴
note that the 0.06 W/m^2 is small compared to the solar input...
solving for the temperature T we get:
T = 255 K
which would be the temperature of the Earth without an atmosphere.
To change that by 1 K to 254K we'd have to set C = -2 W/m^2, that is, the heat flow would be into the interior of the Earth...
this represents a huge amount of energy being sucked into the Earth... the radius of the Earth is 6,378,100 meters the area of the Earth's surface is 5E14 m^2 so the heat is flowing in at 1E15 W
Using Kelvin's 1ºF/50 foot temperature gradient, and the 0.06 W/m^2 heat flow, the conductivity of the ground is something like 1.65 K/m/(W/m^2)
if the interior of the Earth were cool enough to suck 2W/m^2 into the Earth, changing the surface temperature by 1 K, the temperature gradient in the dirt would be -1.2 K/m, this would indicate that the crust 210 meters underground would be at absolute 0 K, the minimum temperature.
The point is, the Sun's energy overwhelms the Earth's interior energy.
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raymond phule
climber
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I'm truly curious if actual climate scientists do the same.
You could read their papers or ask them?
Almost nothing you write make any sense to me but I am not an expert on heat transfer.
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Ed Hartouni
Trad climber
Livermore, CA
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you can calculate it yourself from here:
http://en.wikipedia.org/wiki/Earth's_internal_heat_budget
as I posted that link upthread...
perhaps you didn't look
http://en.wikipedia.org/wiki/Earth's_internal_heat_budget#Global_internal_heat_flow
"Estimates of the total heat flow from Earth’s interior to surface span a range of 43 to 49 TW (TW = terawatt = 10^12 watts).[8] The closest estimate is 47 TW,[1] an average crust heat flow of 91.6 mW/m^2, and is based on more than 38,000 measurements. The respective mean heat flows of continental and oceanic crust are 70.9 and 105.4 mW/m^2.[1]"
I was truly curious about something. It took Ed a while, but he finally calmed down and participated in civil discourse. Thank you Ed :).
you decided I wasn't persecuting you for some reasons imagined only by you?
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crunch
Social climber
CO
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If the interior of the earth contributes little to nothing to surface temperature then it is just a big available heat sink for extra heat then, right? Why would it not be absorbing the extra heat?
It's neither.
What you are missing is that rock is a very, very poor conductor of heat. Transferring heat (no matter whether it is upward or downward) through rock (our crust) is a totally different matter to transferring heat through a gas (atmosphere) or even a liquid (ocean).
The core of the earth, 4,000 miles below, still maintains some insane temperature of around 5,000 degrees, having lost remarkably little heat over ~4 billion years.
Why is this? Heat is transferred in three ways: radiation, conduction, convection.
Conduction involves molecules being heated up, and as they heat up they move around. They bump into each other, transferring their energy onward and outward, like billiard balls striking each other. Rock is a very poor conductor of heat because its molecules are bound up, solid. They can't move very easily.
With rock, there's no radiation because waves of energy (think the UV that produces sunburn, or even basic visible light from the sun) are blocked by the solid rock.
Convection refers to actual movement of material. With the atmosphere, it's wind; with the oceans, it's currents. There is some convection of rock far below the surface (moving the various crustal plates around), but movement is incredibly slow. I've read that the mid-Atlantic is opening up at about the rate one's finger nails grow.
So, back to the short answer: Any effects that the Earth's interior heat has, heating or cooling the surface, is truly negligible, lost in the noise, compared to other effects.
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Chiloe
Trad climber
Lee, NH
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The closest estimate is 47 TW,[1] an average crust heat flow of 91.6 mW/m^2, and is based on more than 38,000 measurements.
And the average continental crust heat flow globally is around 65 mW/m^2 (oceans are higher, so the global average is higher as well). For the borehole temperature reconstructions I graphed upthread (and below), the original data from that particular set of borehole sites gave a mean heat flow slightly less than this, 60 to 64 mW/m^2. Huang et al. presented a set of 9 different curves, which I also graphed. These are paired combinations of 3 plausible heat flow parameters (60, 62 and 64 mW/m^2) with three plausible values of thermal diffusivity (0.9, 1.0 and 1.1*10^-6 m^2/s). It's simple but illustrates another way scientists routinely consider how uncertainty might affect their results.
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monolith
climber
SF bay area
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You are so gullible and ignorant, TGT.
Trend lines are not drawn from any arbitrary point to another, otherwise you can just choose whatever slope you want, like below.
Does this look like no warming in 19 years, TGT?
TGT, thanks for dragging over one of the all time classic cherry picks.
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raymond phule
climber
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You could read their papers or ask them?
Almost nothing you write make any sense to me but I am not an expert on heat transfer.
It must be hard to live in a world were that comment is considered a personal attack.
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raymond phule
climber
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Sorry, if you feel offended when I answer one of Sketch posts...
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AndyMan
Sport climber
CA
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No warming for 2 decades ("It's a travesty we can't explain it" - Trenberth, IPCC)
Arctic sea ice back to normal
Antarctic sea ice at record highs
Rate of sea level rise decreasing
Cyclones at 30 year low
Come on pussies, show us the EVIDENCE to support your scam. Show us the EVIDENCE that man's CO2 has caused any of the warming since the Little Ice Age.
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raymond phule
climber
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"Interesting" blog post. The figure is not from the actual paper and is not showing the method used. It is just used as a rhetoric tool used to misled the usual "skeptics". I am sure that Sketch is angry about such an obvious lie.
WUWT page show the same figure (probably for the same reason) but is at least fair enough to write that it is not from the actual paper (like a real "skeptic" would read the caption of a figure...).
I just skimmed the actual paper but he seems to calculate trends for different time periods and choose the longest time interval when the trend is not statistical significant.
So the trend over that time period is positive but it is a small chance that the real trend is zero so he called it a pause.
Not a very strong result to say the least.
So I guess that we have a positive statistical significant trend of 0.111 deg/decade from 1994 and a pause in warming from 1995 because the trend of 0.0925 deg(decade) is not statistical significant.
I believe that what he does is one very common and of course well known error in statistics. Believing that the null hypothesis is true when statistical significance can not be shown.
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Wade Icey
Trad climber
www.alohashirtrescue.com
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Sketch works the fuel dock concession at Lake 'o Fire Marina.
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WBraun
climber
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Bottom line.
Americans are just plain ignorant and stooopid.
They will only care about "Climate Change" when it actually effects them to the point when there is no more food and water.
Industrialized nations are spoiled rotten.
All their food and water is so easily assessable.
Make everyone grow their own food to survive and they'll wake up real quick on the merits of their stupid Industrialization.
Stupid people you can't eat nuts and bolts and continually rape Nature.
Stupid people you are now suffering the Karmic reactions for your many years of abusing mother nature.
You've been told many many times in the long past not to do this.
You have ignored and are still ignoring,
Thus you will suffer your "Climate Change" which also includes Wars, droughts, extreme weather, genocide, hypocrisy, disease, etc etc etc and general unhappiness all over the planet.
All your cherished freedoms will be taken away and already have been taken away.
You will be bound and chained to the bondage of your past actions.
You are not free to do what you want.
There are the higher laws and they are eternally in action .....
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