Friday, October 4, 2019

A short primer on global energy flows, for the twitter deniers

Sou | 2:56 PM Go to the first of 34 comments. Add a comment
Energy balancing when no forcing
There have been two or three people on the climate denial conversation on Twitter who cannot conceptualise global energy flows. Remember, almost all the deniers in this particular conversation are greenhouse effect deniers who don't "believe" physics and chemistry. Nonetheless they've discovered a wonky diagram in the deniosphere somewhere and have asked how it works. The short answer is, it doesn't. Not the way it's portrayed in their diagram.

Dr Kevin Trenberth has kindly allowed me to publish this updated global energy flow schematic, which is about to be published. (I'll post the doi when it is available.) Here it is, with an explanation below:

Figure 1 | Global energy flows. Source: Kevin Trenberth (pre-publication)

Energy coming in from the sun

Our source of energy is the sun. The sunlight travels as shortwave radiation, which we refer to as "light" (or visible light). It's shown in yellow in the diagram above.

Some of this incoming energy is reflected by clouds and the atmosphere and doesn't get to the surface.

Some of it is reflected from the surface. Ice is a good reflector. Oceans are not at all good and get heated up by the sun (they absorb the energy). Other parts of land vary in how much they reflect and how much they absorb. As you'd imagine, darker colours get hotter and lighter colours reflect more sunlight.

Energy coming up from the surface of the planet

The other side of the schematic (the brownish bits) shows what happens to the energy from the warmed surface. The surface emits longwave radiation, which we'd commonly term "heat" but it doesn't have to be hot or even warm. This energy circulates within the earth system and some goes back out to space. (In a stable system, the amount of energy going out would equal the amount coming in.)

Some of this radiation coming off the surface goes straight back out to space and doesn't stay in the system at all.

Some of it circulates within the system, as I've said. For example, some is absorbed by greenhouse gas molecules, such as water vapour and CO2. The molecules get more energy and can pass some of this energy onto other molecules. Within a few milliseconds they emit the energy back out and drop back to their normal state. That energy (a photon) can go in any direction, so statistically about half the photons head back to the surface (below a 180 degree plane, if you like). This goes on at all levels in the air, so there's lots of opportunity for a photon to hit a greenhouse gas molecule and be absorbed. (I won't go into the technical details here.) That part is shown in the brownish bit of the diagram labelled "downwelling radiation".

Some energy from the surface is transferred to the atmosphere via thermals and evapotranspiration (as water vapour). The latter of course comes back again when the water condenses in clouds.

Stability when energy in = energy out

When the amount of greenhouse gases is stable (not increasing and not decreasing), the whole energy flow stabilises and the amount of radiation coming in from the sun (short wave) is the same as the amount going back out to space (short wave and longwave). However, this doesn't happen immediately because the greenhouse gases slow down the radiation escaping. It takes a while for the system to get into balance. The surface warms up and eventually gets to a steady temperature that is higher than if there were no greenhouse gases. That is, energy is circulating within the system and, while some of the energy from the surface finds its way out, it is being topped up, if you like, by the sun every day.

Increasing greenhouse gases => warming planet

When greenhouse gases are increasing as they are now, then more energy remains in the system than goes out. As the energy system tries to equalise, it finds there are more greenhouse gas molecules than there were the day before, so there's a bigger barrier in the way with every passing day and less energy can escape to space. That's why we see global surface temperatures rising, ocean heat increasing, ice melting, seas rising, and a more energetic water cycle. When the greenhouse gases stop increasing, the system will balance and, once again, energy in will equal energy out, but the system will only cool down as greenhouse gases come out of the system (by photosynthesis, weathering etc.)

The shonky diagram, and why.

A denier put up a shonky diagram and asked for it to be explained. Well I can't explain why anyone would draw it, but I can point out why it's wrong. It's incomplete. (Gilles exhibits strange, indeed disturbing behaviour at times. He keeps saying how he wants to crush people, and that altruism is evil.)

Here is the diagram Gilles posted.

Figure 2 | Shonky drawing. Source: Some dumb denier on Twitter

The top left of the diagram shows net sunlight coming in (239 Wm-2). That is, the amount coming in minus the amount reflected back from the atmosphere and the surface. The bottom middle of the diagram shows the longwave radiation that's been absorbed from the energy radiating up from the surface.

All the bits in between are missing.

The diagram doesn't show sunlight hitting the planet or that reflected back to space. Nor does it show the the amount of longwave radiation being emitted from the surface or the energy radiated from the surface that goes back to space. Nor does it show any of the internal flows such as the water cycle. It's only part of the global energy flow and so one bit doesn't match the other. It's not matching in the type of radiation, one's short wave incoming the other is long wave greenhouse gas received from the surface and emitted back down (not the up bit).

The left hand side is energy from outside coming in. The right hand side is energy circulating within the system. Because the planet is warmer than it would be without greenhouse gases, there's plenty of energy available to circulate within the system. It doesn't all go straight back out to space.

The notations "cold to hot" are a story for another time. (I'll give you a hint. This particular brand of denier doesn't believe that all substances above absolute freezing emit radiation. They think photons are sentient and know when there's a hot or cold object in their path, and decide to emit accordingly. They don't understand physics.)

More energetic nonsense from deniers

Did I mention deniers are conspiracy theorists? This is one of the comments from "JoePublic",  who reverts to primitive vulgarity, cursing and other inanities when he figures he needs more attention. He or she is one of the deniers who's pretending to want to learn about the energy flows on earth.

This was after he asked some "not even wrong" questions - like this and this. Joe is fairly typical of the crowd in that conversation, so you can understand why I say there's little to no hope of deniers learning any climate science.

That's it for now

My explanation above was deliberately kept as simple as I figured was needed so that deniers could understand it. (Not that they will, in part because they've indicated they don't want to understand it.) There is more to global energy flows, of course. You can read more in the references below.

If there's anyone who can't understand all this, or anyone who thinks I got something wrong, let me know in the comments.

References and further reading

Kiehl, J. T., and Kevin E. Trenberth. "Earth's annual global mean energy budget." Bulletin of the American Meteorological Society 78, no. 2 (1997): 197-208.

Loeb, Norman G., Bruce A. Wielicki, David R. Doelling, G. Louis Smith, Dennis F. Keyes, Seiji Kato, Natividad Manalo-Smith, Takmeng Wong, 2009: Toward Optimal Closure of the Earth's Top-of-Atmosphere Radiation Budget. J. Climate, 22, 748–766. doi: http://dx.doi.org/10.1175/2008JCLI2637.1

Trenberth, Kevin E., John T. Fasullo, and Jeffrey Kiehl. "Earth's global energy budget." Bulletin of the American Meteorological Society 90, no. 3 (2009): 311-323.

Wild, Martin, Doris Folini, Christoph Schär, Norman Loeb, Ellsworth G. Dutton, and Gert König-Langlo. "The global energy balance from a surface perspective." Climate Dynamics (2012): 1-28.
Patrick T. Brown, Wenhong Li, Jonathan H. Jiang, and Hui Su, 2016: "Unforced Surface Air Temperature Variability and Its Contrasting Relationship with the Anomalous TOA Energy Flux at Local and Global Spatial Scales." J. Climate, 29, 925–940.
doi: http://dx.doi.org/10.1175/JCLI-D-15-0384.1 (pdf here)

From the hotwhopper archives:


  1. As a biologist energy and nutrient flow diagrams are meat and drink, though having tried to teach them, I sympathise with those who struggle to grok them.

    I note that the recent update raises the energy imbalance from 0.6W/m^2 to 0.9W/m^2. Our situation would not seem to be improving!

    1. Agree, it's a lot to take in particularly for those without any background in this sort of thing. More particularly for people who really, really resist taking it in :(

      If you've any tips for making it easier to digest, I'd love to get them.

      Re the imbalance, that'll get worse before it gets better. The need for strong and decisive action is getting more urgent, isn't it.

    2. A bank account or company accounts can be a useful analogy. A lot of people with no experience of science are experienced in managing money flows. The accounting is similar for both.

    3. Good idea.

      I could use income from the job as the energy from the sun, switching funds between one's own bank accounts as an analogy for energy circulating in the system, and spending money on junk food or science denier books to represent energy going out to space :)

    4. You,ve got it.

      Income is insolation, transfers move energy from one reservoir. The accounts are energy stores like ocean heat content and the overall balance is the temperature. Expenditures are energy flows to space.

      Profit and loss are energy imbalances. Profit is the net accumulation of energy as we warm and loss is cooling.

  2. Am I correct in thinking that the Trenberth diagram depicts an average of the entire earth's surface (both day and night sides), which is then averaged again over time?

    1. It's the overall state of the system, yes.

  3. Trenberth's global energy flow schematic is acceptable, as long as you realise that it is showing long-term averages

    This may come as a shock to Alarmists, but the sun doesn't shine 24 hours/day over the whole Earth. Skeptics divide the 24 hour period into 2 parts, which we call "day" and "night"

    During the day the sun is supplying much more energy than Trenberth shows (about twice as much), to the day half of the Earth

    During the night the sun is supplying very little energy to the night half of the Earth

    This causes a phenomenon which many Alarmists struggle to understand. During the day, the surface temperatures over land increase (on average) by about 10 degrees Celsius. And then at night, the surface temperatures over land decrease (on average) by about 10 degrees Celsius

    Did you notice that the amount of warming during the day, and the amount of cooling during the night, are about the same amount. As long as this is true (on average), then the Earth is NOT warming or cooling (no matter how much greenhouse gas there is in the atmosphere)

    Alarmist scientists like Trenberth, have convinced Alarmists that humans are half awake, 24 hour per day. And that humans live in a perpetual twilight (not too hot, and not too cold)

    I don't want to wake Alarmists from their semi-slumber, but reality is as different from Trenberth's global energy flow schematic, as, well ..., day and night !!!

    To appreciate how weak, and puny, and slow, anthropogenic global warming (AGW) is, you just need to compare the size of global warming, to the size of the average daily temperature change on Earth (over land)

    The average daily temperature change on Earth (over land) is about 10 degrees Celsius (every day)

    Global warming is about 0.02 degrees Celsius PER YEAR

    To compare them accurately, we need to change them both to the same units. We can use PER DAY for this

    The average daily temperature change on Earth (over land) is about 10 degrees Celsius PER DAY

    Global warming is about (0.02 / 365.25) = about 0.0000548 degrees Celsius PER DAY

    So daily warming is 182,625 times greater than AGW

    Don't get upset. AGW is cumulative, but daily warming is normally not cumulative. But AGW can not happen, unless the days warm by more than the nights cool (on average)

    So should you PANIC? Tomorrow will be 0.0000548 degrees Celsius warmer than today (on average)

    You talked about "Stability when energy in = energy out", and "Increasing greenhouse gases => warming planet"

    This is true, "on average". But there is no stable equilibrium. We live in a quasi-stable equilibrium. Temperatures are chaotically changed in a semi-regular pattern each day. Temperature changes over longer periods, are usually corrected over longer periods

    Remember that Trenberth's global energy flow schematic averages everything over time. In reality, the energy radiated from an object varies with the 4th power of its temperature. And the temperature varies by 10 degrees each day (on average over land). But Trenberth doesn't show that

    And don't get me started on the seasons. The temperature difference between winter and summer is often 20 to 30 degrees Celsius. Trenberth doesn't show any seasonal differences. Trenberth assumes that we live in perpetual spring/autumn. There is no winter or summer. Perpetual twilight, in perpetual spring/autumn

    The axis of the Earth in Trenberth's world, is perpendicular (not tilted), with respect to the orbital plane of the Earth around the sun. So please don't assume that Trenberth's global energy flow schematic is completely accurate and real. Do you live in a steady state world?

    AGW is happening. But it is weak, puny, and slow

    Always remember, that the worst thing that you can do in an emergency, is PANIC

    And panicking when there is no real emergency, is the STUPIDEST thing that you can do

    1. There are so many things wrong with what you said, it's hard to know where to start.

      However, your claim that global warming is tiny and slow is absurd. The world is warming at least 10 times faster than when it came out of the last glacial period. It took from 20,000 to 9,000 years to warm by about 5 C. That is an average of 2,200 years for each 1 C warming.
      The planet has now warmed by 1 C in about 138 years. That comes to 16 times faster.

    2. Sheldon, what a gish gallop, and so wrong. Richard is correct.

      Also, I was writing about an energy flow diagram, not a temperature chart. It shows how much energy is coming in, going out, and being accumulated on earth.

      If you think half the planet is in darkness then that same half suddenly flips to light, you'd be wrong. It doesn't work like that. The earth rotates so light and dark move across the surface as the sun goes in and out of range.

      If it makes you feel better to say you'll be able to cool off at night (even as the nights get hotter), and that winter will give you some respite (even as temperatures rise), that's fine. Not everyone lives in a place where nights will cool enough, or where there's a winter to recover in.

      Trying to minimise the problem so you'll feel better is cowardly. (Sheesh, he even tried on the 20 degree change in a season. How foolish. Guess what, we can have 50C difference between a hot day and a cold night over a year and I'm not fooled. I know global warming is real and hazardous.)

      If you're trying to persuade people to speed up global warming that's much worse. That's condemning people to losing their land, livelihoods, homes and, in many cases, their lives.

      Even someone like you should have enough wit to know that letting seas rise six metres in 300 years or less, and having temperatures rise and climate change as fast as we're doing will make many species extinct, destroy almost all coastal communities, and most probably destroy civilisation, certainly as we know it.

      Is that what you really want? (That's a rhetorical question. You've already said it is what you want. Any more rubbish like that from you won't be tolerated here.)

    3. What a screed!!! But I do have to ask: How exactly does the spin axis of a sphere being toasted on one side matter wrt energy in energy out?

    4. jgnfld,

      as I said in my "screed":

      The energy radiated from an object varies with the 4th power of its temperature. So an object that is just a little warmer, radiates a lot more energy.

      And the temperatures during the day are about 10 degrees warmer than at night (on average over land). And the temperatures in summer are often 20 to 30 degrees Celsius warmer than winter.

      Energy radiated is NOT linear with respect to temperature. It increases rapidly, in proportion to the 4th power of temperature.

      Trenberth's global energy flow schematic is based on averaging and "linear thinking", and doesn't show any of that.

    5. I ask again. How exactly does the spin axis does the spin axis of a sphere being toasted on one side matter wrt energy in energy out? Like all good deniers, you neglected to answer the simple direct question about your original assertion stating: "The axis of the Earth in Trenberth's world, is perpendicular (not tilted), with respect to the orbital plane of the Earth around the sun. So please don't assume that Trenberth's global energy flow schematic is completely accurate and real."

    6. People have a lot of trouble because they think in terms of temperature changes, rather than energy flows.

      Temperature is not a physically-conserved quantity. Energy is.

      For a way-over-simplified example, if your daily cycle is +/- 10°C, but each day, you melt a little more ice, you have global warming.

    7. jgnfld

      Somebody above suggested using income to illustrate energy flows.

      Imagine a simple example based on income and tax.

      You get paid weekly, and tax is 10% of the first $100 earned, and 20% on any income above $100.

      Sound simple? Tell me what your average tax rate (flow) is.

      Answer - you can't, unless you specify the income payments.

      And if your income varies from week to week (like incoming energy from sunlight varies over the day, and over the seasons) then you end up with a very complicated non-linear problem to solve.

      The spin of the Earth means that the input energy varies with time of day. And the tilt of the axis means that the input energy varies with the seasons (or month of the year).

      The energy flows of the Earth are much more complicated than a simple income tax example. But even the simple income tax example is not easy to solve.

    8. Sheldon, the fact that science isn't easy and can require advanced tech to measure the tiny deviations in TSI doesn't mean it's not possible. On average, Total Solar Irradiance is 1,361 W/m2. This is top of atmosphere at a point perpendicular to the sun, and averaged out is ~340 W/m2 over the top of the atmosphere.

      To use your analogy, you're saying it's too hard to know if the $1,000 in your bank account has any meaning because it changes by a fraction of a cent up or down over the day.

    9. Again I ask: How does the spin axis of a sphere being toasted affect the total energy in energy out of said sphere? The energy in is constant and spin axis can have no effect on it--it coming from the heat source, after all. Therefore you must be implying that the energy out depends on spin axis. Explain how the spin axis changes the energy out.

    10. jgnfld: The heat transfer is proportional to the fourth power of the temperatures. Thanks to the spin axis, the heating is not uniform nor constant, and a warmer region radiates a lot more to space than a colder region.

      Warmer-than-average regions ("summer") emit a lot more than regions at the average temp, and cooler-than-average ("winter") isn't enough cooler to compensate.

      But that's just one of many factors related to spin and the spin axis. Cloud cover, surface albedo, heat transport by wind and water currents, are all affected by spin and the spin axis.

      And all affect energy out.

      This is why the detailed physical models, rather than people sitting at their keyboards declaiming whatever oversimplification strikes their fancy.

    11. This comment has been removed by the author.

    12. All I'm asking Sheldon to answer is a simple question: In a setup where a rotating sphere sits next to a source which puts say 100watts/m**2 into the sphere how does the spin axis affect the the total energy out. Or does it equal the amount coming in?

      Sheldon's comment clearly implies energy in does not equal energy out. As you note above temp and energy are 2 eifferent things.

    13. I never said that the spin affects the total energy in or out.

      If the Earth is in equilibrium, then the energy in equals the energy out. Regardless of the spin.

      But the spin does affect the temperature of the Earth.

      With a faster spin, the difference in temperature between the day side and night side of the Earth is smaller.

      With a slower spin, the difference in temperature between the day side and night side of the Earth is bigger. Like on the moon.

      Because energy radiated varies with the 4th power of the temperature, this temperature difference affects the maximum temperature, the minimum temperature, and the average temperature.

      So the temperature of the Earth is affected by more than just the energy in and energy out.

      As well as the day/night and winter/summer differences, the latitude has a huge effect on temperature.

      There is a temperature gradient going from the equator to the poles. And because energy radiated varies with the 4th power of the temperature, this also affects the temperature of the Earth.

  4. Sou,
    Wow,...dabbling in the physics?
    Here's a conversation between myself and David Arthur you should take a look at. My real name is used,and I must curb my tongue, and be polite...
    Regards as usual,
    Sky Dragon Slayers Chief Public Relations Officer

    1. Are you still hawking your flat earth theory, Mack? After all these years, you still haven't figured out the planet you're on is roughly spherical in shape.

      Mack with his flat earth theory in 2014. He's also a greenhouse effect denier.

      I still wonder sometimes...

    2. Yes,correct, Sou, I am a "greenhouse effect" denier. Here is a comment clarifying the LACK of any "greenhouse effect" in Earth's atmosphere....
      Hoping that helps you in your understanding.

    3. Now you're saying at the top, the atmosphere unravels itself from a spherical shape and somehow unfolds into a flat plane. That idea is even weirder than claiming the earth surface is flat.

    4. "That idea is even weirder.." To the contrary, Sou. What you said there is a good thinking process describing a YEARLY GLOBAL AVERAGE..... just re-wrap the flat plane back around the globe and there's your yearly global average. It actually can be physically witnessed in the fact that the molecules of atmosphere at the very top of the atmosphere... pretty well out in space.. don't revolve around at the same pace as Earth's surface... in fact they are practically stationary.
      Same with the sun, stationary at the TOA... along with those molecules. All the rotation of night and day and Earth curvature geometric calculation ,only applies to right down at the surface. Trenberth and the rest, in their calculations,has the sun going around and around the Earth at the TOA...the sun rising and setting at the TOA . That's how they get their, geometrically calculated, huge mistake of 340w/sq.m at the TOA.!!
      So that's a good open minded query on your part, Sou. (no sarc.)

    5. Mack, just because you claim the top of atmosphere is like a flat piece of paper floating between the earth and the sun, keeping it's position while the earth revolves around the sun, doesn't make it so.

      (In case there's another flatearther out there wondering, the atmosphere surrounds the earth and is also more or less spherical in shape:
      Layers of the atmosphere
      . The top isn't separate from the rest, nor has it separated from the rest of the atmosphere and moved to some flat plane.)

      That's enough of your nonsense. Feel free to try your ideas out on the flat earthers.

    6. No your analogy is correct, Sou. It's even depicted in all the books. The Earth as a round ball and multiple rays from the Sun evenly striking the entire surface, as in a flat plane.

    7. Are you saying light bends, or are you saying the atmosphere at the top is unfolded into a flat plane?

      If the former, how does light bend in a vacuum?

      If the latter, what's in the huge gap between the flat plane and the rounded rest of the atmosphere? Is it a vacuum (and what's holding it up against gravity?). Or is it propped up with fairy floss or something to keep it flat (and how does light get through the fairy floss)?

    8. You're still keeping your mind down here on the Earth's surface,Sou. Out in space, where the TOA is, nothing revolves,the sun is always coming from the same direction..."in the sky" ..so to speak. The Sun is always the same distance away .."in the sky"...the distance difference from the Sun in any position outside the Earth's shadow, at the TOA is so insignificant that the Sun is always "overhead". Always blazing away at about 13 hundred, something watts/sq.m at the TOA.

    9. You probably meant rotate not revolve, but you'd be wrong about that too. The atmosphere sticks to the earth, it's held on by gravity. It revolves around the sun along with the earth and spins along with the planet when it rotates on it's axis. (Some maybe spins even faster.)

      Solar energy hitting at top of atmosphere is measured at a point where the tangent is perpendicular to the sun. It's less at any other point. Averaged over the whole surface it's ~340 W/m2.

      I guess you are unable to visualise shapes, Mack. Maybe I'll explain in a blog article, with diagrams.

      I realise that since you've not figured it out in five years or more, you're unlikely to ever do so. It's like someone who wants so desperately to believe in fairies at the bottom of the garden they continue to believe it long into adulthood.

      Still, for anyone else who's confused, Mack's wrong. The atmosphere doesn't keep unfolding itself onto a flat plane as the planet rotates. It remains more or less spherical, bound to the earth by gravity. That means at any instant there's a point at which there's maximum solar radiation. That point keeps shifting as the earth rotates, as night follows day etc. Every other point at that instant has the light coming in at an angle so it doesn't get the full blast, and a lot of the top of the atmosphere is shaded by the earth itself.

      Here's a link showing how the incoming solar energy averaged over the whole planet at the top of the atmosphere is worked out.

  5. Well,my bad...I didn't know about the super-rotation of the very thin air up at the 200km range. That super-rotation would probably have something to do with an extreme temperature dipole between the molecules on the sun facing side of the TOA , which is nearly CONSTANTLY facing the sun....and the shade side of the TOA...out of the sun (for the time being, over.. one year the whole of the TOA would be in the sun)...the hot molecules racing around the whole planet to the cooler side.
    "Averaged over the whole surface it's about 340w/sq.m."
    There you've fallen into the mistake of the "surface." Like your last link in that comment, there is a subtle, seamless, shift from talking about the solar radiance arriving at the "surface" of the Earth at the TOA... and the real Earth's surface we are standing on....the surface where the sun rises and sets.
    How could it possibly be such a low average at the TOA, Sou.? Even if you put a satellite up 200ks at the TOA, above one or both of the poles of this planet, you would still get a solar reading of 1360 w/sq.m. It's still that solar TOA reading of 1360w/sq.m. causing the Northern and Southern lights.
    Whoops, light shining at nighttime, also.

    1. "How could it possibly be such a low average at the TOA, Sou.?"

      Read, think, do diagrams, build a model (use an orange for the sun and a marble for the earth), whatever it takes. Ask your wife, child or grandchild. Ask your neighbour or local high school teacher.

      There's about a 0.001 +/- 5% chance you'll figure it out some time in the next twenty years, Mack. All the information you need is there. It's now up to you to put it together in your own mind.

    2. "Ask your neighbour or local high school teacher"
      "Local high school teachers" would be the last people I would consult. High school teachers are the ones who've got our kids irrationally gluing themselves to objects in the street.
      "How could it possibly be such a low average at the TOA, Sou?" ....is the question you didn't really answer, Sou.
      WRT "Read, think, do diagrams, build a model"...apart from the "think"..in my opinion, there's too much set reading of what other people write,too many diagrams, too many models. What is lacking is scientific observation, then the thinking.
      For example, it is observed by newer outer satellites in the SABER study, that with an active Sun, you can actually see the glowing of the waste molecules of nitric oxides and CO2 in the upper atmosphere as they shed their heat into space. So where does your, and Trenberth's, average of only 340 watts/sq.m arriving from the Sun at the TOA, fit into this observed fact, Sou ?


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