Lessons From A Watched Pot

I have these nice cooking pots with glass lids. I like to watch them when I cook, and I like to think while I’m watching.

So a couple of days ago I was making potstickers in one. The frozen / boiled ones. You ‘bring the water to a boil’ then add the potstickers and wait for it to come back to the boil. I tend to put a lid on as things heat faster then on less fuel.

So I’m staring at the pot, as it slowly warms. The glass lid first fogs, then drops form and run back down into the water below.

It occurred to me, while staring at this watched pot, that it is a more faithful representation of how the Earth cools than the computer models that attribute it all to CO2.

The pot is heated from the bottom, as is the atmosphere. sunlight warms the ground. This heat is predominantly put into the air over the surface by water vapor. Plants transpire copious amounts to stay cool in the sun. Other places just have the surface water evaporate. That water vapor is light, so rises and cools from expansion as it does.

Water vapor in the pot rapidly runs into the lid. CO2 in the pot doing nothing at all. Just like the tropopause is above our atmosphere of air and water vapor. In both cases, the water vapor condenses. The pot lid forms dribbles of water returning to the ‘ocean’ below it. Similarly, cloud tops dump heat upward while water / precipitation falls back to the surface to be once again evaporated.

The pot lid dumps heat by a combination of convection and radiation. The atmosphere has the heat radiated away from just above the tropopause. BY DEFINITION: the tropopause is the place where convection fails, and heat transport by radiation can begin.

So watching that pot boil, it is simple to see what drives it. Water is evaporated by applied heat. It rises until it can rise no further, then condenses as precipitation. This puts heat into the ‘lid’ (or stratosphere) where it can radiate away.

Increase the heat, you get more water mass flow; and more heat moving with it. Minor changes to CO2 (such as breathing in the kitchen) do nothing to change the heat transport of water vapor, nor to change the temperature of the pot.

Vastly more heat can flow as water vapor and condensation that can ever move via radiation in the air in the pot.

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About E.M.Smith

A technical managerial sort interested in things from Stonehenge to computer science. My present "hot buttons' are the mythology of Climate Change and ancient metrology; but things change...
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25 Responses to Lessons From A Watched Pot

  1. p.g.sharrow says:

    add; the lid increases the vapor pressure on the liquid in the pot increasing the temperature of evaporation and therefore the temperature of the liquid, cooks faster. The real green house effect!…pg

  2. beththeserf says:

    Lefties luf ter think closed systems.

  3. oldbrew says:

    It was always about water vapour not CO2. They invented the enhanced greenhouse effect to claim that more CO2 would cause more water vapour, which would then somehow confuse the climate system and make it go out of control – the ‘runaway greenhouse’ idea as per climate models.

    Of course these models are now so out of step with reality – too much warming – they are embarrassing, but still are relied on by the IPCC and its followers.

  4. Gary says:

    And if the boiling gets too vigorous, we turn down the heat. Sort of like clouds dampening the incoming sunlight, except we think about the boil over and they don’t. They just do their thing.

  5. E.M.Smith says:


    I immagine you could simulate that effect too if heat were applied via IR through the glass and as the glass fogged up it acted like a cloud… built in negative feedback. It would have limits, though. The condensation on the glass eventually runs off. It’s 2 D where clouds are 3 D structures and can change altitude.

    On one trip across the USA, I took a series of photos on I-80 from about Nebraska to Georgia. From sun rise to set. Through the day, it started as clear; then sun warmed grasses put vapor in the air and low level clouds formed. They eventually evaporated under stronger morning sun, but reformed mid level after rising. The final step was a fairly full cloud deck high up. A “pulse engine” driving water vapor higher in pulses. Stopping to condense when cool enough, and picking up some more sun for the next pulse higher.

    Near as I can tell from reading the climate model code, they have nothing even remotely close to that dynamic of clouds in their codes. More of a “plug number” (parameter) for general cloudiness and then some water vapor feedback parameters. Modeling cloud formation is hard to do and sucks a lot of CPU cycles, so tends to be ignored. Yet it’s the main vehicle for heat transport from surface to tropopause…

  6. Larry Ledwick says:

    Yep the thunder storm is just a special case of very vigorous heat transport by buoyancy driven convection, like the pot suddenly transitioning from quiet simmering to full on rolling boil it just corresponds to a more aggressive version and flips the transport into a second stable configuration (it is stable as long as the inflow of warm moist air is maintained at the base of the thunderstorm has positive buoyancy when lifted compared to the dryer cooler air surrounding the storm.)

    The atmosphere just acts like a spherical heat pipe with the heat source in the center and the heat sink in space (by radiation).

    The water vapor heat transport is only partially driven by the fact that water vapor is lighter than air, it is also driven by differences in vapor pressure. Close to the surface the water vapor vapor pressure is higher than it is just slightly above it so the water vapor simply diffuses to the area which has the lower vapor pressure. This creates a continuous vapor pressure gradient that wants to move in the same direction and the gradient created by gravity and buoyancy of the lighter water vapor in air.

    Like in a steam engine as the water vapor cools and condenses against the lid it creates a drop in vapor pressure (steam engine condensers operate at vacuum pressures if they are efficient), so you literally have the lid pulling vapor toward it due to that local temperature and pressure drop.

    Inside a commercial heat pipe (as used in CPU coolers etc.) these pressure differences in the vapor can drive very high vapor velocities resulting in thermal conductivity 1000x that of metallic conductors like copper.


    Seems that a heat pipe structure thermal conductivity depends strongly on the transport of working fluid to the hot end of the heat pipe. In the case of the earth then heat transport would be highest where liquid water was readily available (sea surface shallow lakes and streams) which have highly efficient absorption of incoming solar radiation. Light colored dry surfaces (desert) would have significantly lower ability to dump heat to higher altitudes because it lacks the efficient heat transport of water vapor. As a result surface temperatures have to rise to much higher levels to efficiently move heat from the hot surface to cooler high altitudes by radiation since convection due to buoyancy of hot dry air is not nearly as strong as if it was saturated with water vapor.

    Like the old campaign sticker we need bumper stickers that say “Its the water vapor stupid!”

    Heat pipe efficiency also depends on the ability of the working fluid to return to the heat source, in the case of the earth that return path is predominately rain and other forms of precipitation or lateral surface flow (ocean currents) into the hot area.

    From reference above:
    Capillary Limit

    Maximum heat that can be transported by the heat pipe before vapor pressure (from Hot to cold regions) and gravitational force exceed fluid capillary forces (from cold to hot region), i.e., fluid does not return fast enough or does not get back to hot region. Dry-out occurs in the evaporator region when capillary limit is reached. Heat pipes no longer function properly if dry-out occurs.

    Possible solutions: modify heat pipe wick structure design, increase heat pipe diameter, add more heat pipes or reduce input power.


    The capillary pumping pressure is the only driving force to circulate the working fluid inside the heat pipe. Higher chances of dry-out in a longer heap-pipe as the vapor has a greater distance to travel to the condenser section. Therefore, a bigger diameter heat pipe may be required for longer distances.


    Heat pipes with larger cross sectional areas (i.e. larger diameter of the heat pipe) allow more vapor to be transported from the evaporator region to the condenser region. Heat pipes with larger cross sectional areas have higher heat transport capacity.

    This raises an interesting question. Does an ice age develop because the earths “heat pipe” gets too efficient and dumps too much heat to space, rather than solely due to a change of heat input energy?

    Using the “larger diameter heat pipe allow more vapor to be transported” model, could the ice ages be triggered by both changes in heat input and changes in heat transport to space?
    Would dropping heat input change the heat transport process (wet Sahara desert would dump heat more efficiently than a dry Sahara desert)?

  7. cdquarles says:

    Hmm, Larry, I’d say velocity driven convection. Faster moving gas particles will move upward relative to slower moving gas particles at constant pressure. The same with locally heated liquids. The liquid near the source becomes relatively faster moving. Liquids, which are much less compressible than gases, would have a smaller density gradient internally and a high one at the surface; though liquids with a high surface tension would have that act against it and thus look like the pressure difference was lower with respect to the bulk liquid.

    About an over efficient heat pipe, it certainly could.

    That said, we are in an interglacial period embedded in a geological ice age. We won’t be out of this ice age until all of that perennial ice melts.

  8. E.M.Smith says:

    “Higher chances of dry-out in a longer heap-pipe as the vapor has a greater distance to travel to the condenser section.”

    I’d been pondering how the “lower atmospheric height” caused times to be cooler as the UV dropped off. I think this could well be part of it.

    A higher fluffier atmosphere height has a “longer heat pipe” and more dry out (higher ground temps) and slower mass flow.

    What have we got now in the low UV regime? “Shorter heat pipe” with less dry out, cooler surfaces, and much higher mass flow … all those heavy rains, floods, etc. etc. all over the planet post UV falloff….

    It sure seems to fit…

  9. Larry Ledwick says:

    It sure seems to fit…

    Unfortunately as you well know, we are really only in the early observation stage of a proper scientific investigation of climate. Too bad the “scientists” have not figured out that they have no where near enough input data to develop a comprehensive theory about something as complex and inter-related as climate.

    Their “facts” are really just hints about what to observe and fit into the puzzle which will define what the hypothesis must successfully describe.

  10. cdquarles says:

    Larry, one thing to me is that ‘climate’ is a statistic. How do you observe a statistic? We observe the weather and *that’s* the thing that is important. The weather, not the climate. The climate is determined by the actual local weather. The weather isn’t that complicated. Heck, I’d say that human physiology is more complicated than the weather.

  11. Larry Ledwick says:

    Hmmm under collecting observations:
    I wonder if anyone has put together a historical record of the advances and retreats of vegetation in the Sahara. I know the modern satellite record is showing world wide greening (attributed to higher CO2 making plants more efficient and less subject to drought.

    In the past they attributed the greening and increased wetness of the Sahara as the “result” of the ice age, what if that is backwards and the increased vegetation cover provided more water from transpiration to allow cooling and dumping the excess heat.

    Just suppose the current belief is exactly backwards?

    Higher CO2, leads to greening, greening leads to more moisture retention and transpiration from more drought tolerant vegetation which grows faster, which leads to higher low level humidity, which leads to more effective humidity driven thermal convection (humid atmosphere being essential for atmospheric instability and generation of strong convection cells) to transport heat to high altitudes where the increased CO2 more effectively radiates the heat away to space.

    That chain of events also seems to fit as well!

  12. E.M.Smith says:

    Hmmm…. and fits backwards too…

    Depth of ice age glacial, CO2 drops, plants die off and dust level rises, humidity dropping, heat pipe stops working so well and we get an interglacial warming pulse as the heat pipe shuts down…

  13. Graeme No.3 says:

    Larry Ledwick:
    I thought that the old time view that increased solar heat caused more evaporation in the Tropics, which caused the Hadley cells to expand bringing rain to the Sahara would operate. Hence the greening noted in the Holocene optimum as shown in the Tassili frescos.
    It may well have required feedback from evaporation from trees as per the well known effect over the Amazon forest.

  14. cdquarles says:

    A point about radiation …. water is much more active across much more of the spectrum than carbon dioxide is. Water’s profile is pretty much a continuum spectrum, and part of that is due to the strength of the hydrogen bonding of water. Carbon dioxide’s isn’t, on planet Earth. An absorber is an emitter depending on conditions. That said, thermodynamic temperature is about internal kinetic energy. Radiation isn’t about internal kinetic energy, necessarily. For light to heat something, the absorbed energy has to be converted to internal kinetic energy. For light to cool something, the internal kinetic energy has to be converted to light, reducing the internal kinetic energy. On Earth, water is key and water’s chemistry is much more interesting than carbon dioxide’s. That said, carbon’s chemistry is much more that just that of carbon dioxide.

  15. Larry Ledwick says:

    The one clinker in that theory Graeme is that thunderstorm activity is self limiting. Once you get large thunder cell development, they put up huge anvil clouds which shade the ground and cut off local heating. It is like drawing the blinds in a window.

    We would see this on a daily basis when chasing storms, once the clouds developed, they cut off the heating and storm activity moved to some nearby location which still had solar heating and had not been cooled by rainfall below the critical temperature necessary to trigger storm development.

    Thunderstorms act like thermostats. They do nothing until they hit a set point determined by local air conditions and instability (mostly humidity levels and temperatures) then once triggered they aggressively dump heat to high altitudes and cool the ground with cool condensed water vapor as rain or hail.

    A thunderstorm can take a high 80 low 90 deg F Day of sweltering heat on the plains become a very chilly low 70’s to high 60 deg F in a matter of an hour or so over hundreds of square miles.

    That is an absolutely incomprehensible amount of energy dumped in a matter of minutes.

    So at some point, it makes little difference how warm it gets, because you have nearly 100% cloud cover and almost continuous rain as in south east Asia monsoon season. The on off action of storm development only functions on the fringes in the intermittent humidity and temperature regions.

    Once that switches on solar energy is significantly limited due to high cloud albedo.
    Some of that expansion might take place, but I have seen studies that much of ground moisture is recycled many times (just like in a heat pipe) where it evaporates from the ground and plant evapotranspiration, rains out and comes back to the ground where it recycles over and over and over again. Only about 3% of rainfall actually gets to a local stream.

    But each of those cycles carries thermal energy to high altitudes where it can be easily radiated to space.

  16. Larry Ledwick says:

    Ref Hmmm…. and fits backwards too…
    And the profile of sudden heating implies that there is a sharp cut off to that activity – perhaps the starvation concentration of CO2 near 250-280 ppm where suddenly plant growth becomes stunted and dies.

    The CO2 record seems to show a CO2 floor somewhere between 250 ppm and 180 ppm which the climate never seems to go below.


  17. wyzelli says:

    Here is a pretty cool timelapse of an effect I can actually witness regularly (from my window at work).

    This is heat rising over Channel Island Power Station and pulling moisture up with it. The effect is eventually swamped as the sun rises and the land around Darwin Harbour starts to heat up. The title of the video suggest this has something to do with the LNG ship being loaded but I think that is wrong.

  18. Larry Ledwick says:

    Cool !

    Local heat source creates convection that rises above the LCL (lifted condensation level) the warm moist air condenses releasing heat and rising further but as the heat dissipates and warms the nearby air the moisture re-evaporates.

    You can see the same sort of dance as the atmosphere is getting close to the cap temperature to trigger storm development. Small cumulis clouds form and like a coffee percolator those little puffs rise and dissipate. If conditions are building toward thunderstorm development they gradually be come bigger and repeat more frequently then sooner or later one of the breaks through the cap and you are off to the races.

    Most people perceive storm clouds as being nearly stationary but they are actually quite active if you have the patience to watch them over time, (or have a time lapse camera setup)

    thunderstorm development

    time lapse storm cloud development

    super cell

  19. Thank you Chiefio for a neat demonstration of energy transfer via latent heat. Something that affects temperature gradients in tropospheres of bodies like Earth and Titan that have oceans.

    Then there is energy transfer via convection that dominates in tropospheres, especially where no oceans are present (Venus, Jupiter, Saturn, Uranus & Neptune).

    Then there is radiation that dominates in stratospheres.

    Fortunately Robinson & Catling have provided a mathematical model that combines the effect of all three processes. Energy transfer by conduction has been ignored:

  20. cdquaries, you maybe mixing up emissivities of water and water vapor. The emissivity of water in the temperature range 273K to 373 is something around 0.95 (some people assume it is 1.0 but check table 5-6 in the Chemical Engineering handbook)) The oceans have a lower emissivity at the surface due to air bubbles from waves and a non flat surface. The emissivity of ice varies depending on the surface colour and air inclusions -it can be as low as 0.3 and as high as 0.85. The emissivity of water vapour depends on temperature, pressure and path length through the gas. Radiation from a gas containing water vapour has to be considered on a volume basis rather than surface area for solids and liquids.The emissivity of clear nozzle mixed natural gas (methane ) flame of clear slight blue colour at temperatures around 700-1100C is about 0.45 which is very close to the emissivity of water vapor ie CO2 contributes almost nothing to the radiation from the flame. As well as I can remember the emissivity of “dry” steam at around 130-150C is around 0.42. The emissivity of air in the first 10m of height containing about 1.5% water vapor (on average) and 400ppm of CO2 at temperatures around 30C is so small to be unmeasurable.Heat loss from steam in a steam pipe to the inner pipe surface is mainly due to convection and not radiation.The flow of heat through the pipe is by conduction and then the outer surface of the pipe radiates.
    So called “climate scientists” have no understanding of heat transfer.

  21. gallopingcamel says:

    The emissivity of surfaces is of immense importance when modeling surface temperature. In order to match observations for our moon, I had to set the emissivity of the moon to 0.950. Values of 0.94 or 0.96 simply did not work!
    For incoming radiation the situation can be more complex. For example in the case of our moon the absorbance (1-albedo) depends on the angle of incidence. In other words our moon is “Non-Lambertian”:

    I have been trying to improve on the Robinson & Catling model using Finite Element Analysis but things are not going well. Your information about the emissivity of oceans may help.

  22. cdquarles says:

    @cementafriend, I am speaking of spectra (I’ve done spectroscopy), not necessarily emissivity as such. And I’m talking water in all of its phases in general terms. Now if we are talking high resolution work for specific conditions, sure, the general terms won’t apply.

  23. bruce says:

    IF I didn’t know better, it sure looks like a thermal hot spot in the water. Strange that the breeze appears to have no effect. I know I’d lose myself in watching that, is there someone in the office that will drop a pencil when the boss walks through?

  24. wyzelli says:

    Hi Bruce.
    That movie was taken from approximately the marker at the top of this image, directly towards Channel Island Power Station at the red marker. The LNG vessel is moored at the visible wharf near the centre of this image. Channel Island Power Station operates gas turbines.

  25. bruce says:

    wyzelli, yeah , I noticed that when I reread your post. Jumped in to post before I knew what I was talking about. From the movie alone it looks to the unaware like the cloud is forming out in the middle of the bay.
    sorry to all for wasting space.

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