Saturday, February 15, 2014

Michio Kaku's theory of polar vortex

NewsBusters, WUWT, Climate Depot, and other skeptical websites have been mocking Michio Kaku's CBS shtick:

Kaku has "explained" the snowy Northeast and Midwest and the relatively dry Californian weather in recent months as the result of the same cause, the "instability of historic proportions" that affects the polar vortex. He could have added the floods in the U.K. as a consequence, too – so that his fairy-tale would become even more global. ;-)

The climate skeptics are making fun of the string field theorist's new book about futurism and the mind. Kaku seems to be keen on telepathy and ESP, according to some sources, which is insane.

But I must say that his musings on the polar vortex look at least slightly more sensible than most other phenomena routinely attributed to the "climate change" by the man-made global warming cultists. At the end, I think that the effect is too small and most of the measurable quantities cancel – or at least they are not making any things worse – but his "theory" has a point.

Recall that a polar vortex is a persistent large-scale cyclone located near the North Pole (and another one near the South Pole). You must realize that it's normal for the pressure near the poles to be lower; see the current wind and pressure map near the North Pole.

Now the question is how clear, sharp, and straight the boundaries of the polar vortex are and how close to the pole the center of the polar vortex may be – and how these questions depend on the polar-equatorial temperature difference. I think that if we assumed some overall warming, the rate of the warming would indeed be faster near the poles because of the extra strong positive feedbacks such as the ice-albedo effect (in the tropics, the negative feedbacks may dominate). In the case of the North Pole, this evolution is being observed; in the Antarctica, the warming of the pole is not seen. So the empirical evidence that could back the paradigm is mixed.

But let's just assume that the Northern polar-equatorial temperature difference is decreasing with time, whatever the reason is. What the consequences would be?

The primary consequence of such a drop is the expected decrease of overall temperature variations – although the effect may be too small to be measured. It's easy to see why: if the interval of temperatures achieved on the Earth is shrinking, so are the intervals that one may achieve at any place of the globe. You should realize that much of the extremely warm/cool weather in your town is due to the winds going from the tropics/pole, respectively, so if the difference between the pole and the tropics shrinks, so do the temperature variations induced by Southern and Northern winds.

The overall storminess is expected to decrease, too. That's because much of the storminess is fed by the temperature gradients. The polar-equatorial difference is a major source of the gradients so if this source goes down, so should the storms. Again, the effect may exist just in principle and it may be undetectable when the actual temperature changes are substituted.

But another expected effect resulting from the smaller polar-equatorial differences is pretty much what Kaku mentioned. The polar vortex "sits" near the North Pole because it's a bottom of a bucket. When the temperature differences go down, the bucket becomes shallower, so it is easier for the water to spill from the bucket. So the jet streams – winds that pretty much move along the boundary of the polar vortex in our case, to simplify the discussion – have a smaller reason to follow the parallels of latitude. Latitude's importance for determining the temperature decreases, so the trajectories of the jet streams may become more chaotic.

Just to be sure, jet streams are always meandering – meanders are the wiggles similar to those on the rivers – but I do agree that if the polar-equatorial temperature difference goes down, one should expect the amplitudes of these meanders to increase. So the winds of the type we know from the Arctic are more likely to get further to the South, and vice versa: the "out of the polar vortex" weather may sometimes get into the Arctic. I believe that with the observed changes of the polar-equatorial differences, the effect is still pretty small and, when the noise is taken into account, it is probably unobservable (especially because the Arctic weather itself is getting less extreme). But I do agree that in principle, Kaku has a point.

My order-of-magnitude estimate of the effect. If the polar-equatorial temperature difference drops from 39 °C to 36 °C, for example, by less than 10 percent, the typical distance from the North Pole where the jet stream "often" reaches could grow by 10 percent, too – from 3000 km to 3,300 km, for example. So potentially, some of the more Arctic weather in a thin strip of America could be largely attributed to the wider meanders.

Completely different questions are: What is the reason that the pole-equatorial difference is shrinking (on the Northern Hemisphere) if it is? Why the Southern Hemisphere doesn't seem to follow the trend? And if these changes are occurring, are they good or bad for the mankind and for individual regions, ecosystems, and economies?

I would like to stress that the polar-equatorial temperature difference is independent from or orthogonal to the global mean temperature, in the sense of the spherical harmonic's being orthogonal (I mean \(Y_{00}(\vartheta,\varphi)\) and \(Y_{20}(\vartheta,\varphi)\) in this case), and this polar-equatorial temperature difference is arguably more important than the global mean temperature. During many geological eras, it has changed by dozens of degrees (recall palm trees in the Antarctica). Ask Richard Lindzen, he will tell you why the difference has been more important for the character of the climate on much of the Earth than the global mean temperature. So it is highly contrived to blame "global warming" (and/or CO2) for the changes of the temperature differences.

Second, whatever the cause is, if the effect is happening, the consequences are probably small and probably as beneficial as harmful. The net benefits may be very small and of uncertain sign. This adds up to the clear positive benefits of the expected lower overall storminess which seems to be the primary consequence. So it is completely irrational to start to panic as if something bad were happening. Even if the climate is changing in this way, it doesn't follow that there is any bad news going on. The climate is always changing. Changes are always good for someone and bad for someone else.

It is adequate to mention that most of these "explanations" are not really "explanations" at all. They are just rephrasing the problem and the data (snow here and there, no snow there, and so on) in different words (meander's shape having an extra wider wiggle etc.) – perhaps more specific words but still words that don't allow us to predict things. The cold or snowy weather in some parts of the U.S. may be partly attributed to the more wiggly meanders in the jet stream (Rossby waves that get further away from the North Pole) but we still don't really know the cause of either and we can't predict what will happen with these quantities in the coming years or the distant future. Sometimes, the meanders are wider, sometimes they are narrower. They may get narrower in 30 years on the Northern Hemisphere but the effect may move to the Southern Hemisphere in 2073. Nobody knows. It's mostly a chaotic system controlled by its internal, largely unpredictable processes.

The dry weather in California and the snowy Northeast etc. may be "grouped" into the same story but their anticorrelation isn't a general rule. There are other stories that would describe very different combinations of the weather conditions in various regions of the globe. So if we draw, hype, and personify a "global picture" of the weather, we're not really explaining anything. We're just merging several previously independent pieces of data. It is utterly preposterous to say that there is a "big story" going on here. It's just some weather – a pretty random thing – at random places of the globe. Meanders and gradients have always existed and they were behind lots of harsh winters. People were not religiously obsessed with these phenomena and they were not attributing far-reaching consequences and interpretations to the effects that caused one kind of weather or another. By being less exposed to this scientific terminology without a scientific beef, they were paradoxically acting more rationally than many folks today including Michio Kaku.

Something off-topic, only linked by the Asian ancestry. Play the video above to see what you have to learn, dear Caucasian and African Ladies and Gentlemen, if we want to remain competitive with Asia. Good luck. ;-)


  1. KooKuu blames this on : "Why is this polar vortex weakening? We think it's because of the gradual heating up of the North Pole. The North Pole is melting." The currently frozen sea ice on the North Pole is melting?

  2. You should examine the work of Vaclav Bucha (Prague, Physics Inst.) and company on geo-magnetics & jet streams. There is a 2002 paper in Science on the 'top-down' drag of the jet streams as well. I will have to look that one up.

  3. Lubos,

    An off-point climate question. Consider the coupled systems of partial differential equations governing the global atmosphere and ocean basins. Have you an opinion on what mesh size is required in algebraic discretizations in order to adequately resolve the cascade of energy from large to small scales in the turbulent flow? My view is that the current 100 km cells in the non-radial direction are way too large and result in statistical noise overwhelming computations in weather simulations of only weeks or months (hence the global predictions a century out are not based on the full dynamics but rather very simplified models with parameters selected to please overlords).

  4. Dear Tom, I am afraid that the required resolution strongly depends on the question you want to ask; and on the precise numerical method, too.

    There are clearly patterns in the turbulence etc. that are shorter than 100 km. On the other hand, many of them are inconsequential for many "more global" quantities you may want to calculate. And many of these short-distance patterns and flows may be taken into account if the cells remember the distribution of the speed and pressure etc. in a "smarter way", like in terms of a few Taylor coefficients in the cell.

    If one wanted a truly realistic simulation, it would have to be 3D - taking the height of the atmosphere as an independent variable into account. In that case, cubic cells would probably be needed and their side should probably be much shorter than the height of the atmosphere, i.e. 10 kilometers or so.

    I would also add that I think that even if one constructs the best model with a very tiny box size, it will pretty quickly start to deviate due to some exponentially growing "chaotic" effects, so too much brute force may be a useless overkill.

  5. Thank you. From your last paragraph I think we agree that the global warmers’ predictions are mostly BS.

  6. I really don't buy Kaku's idea, seeing as it appears to run counter to actual observed trends that indicate the opposite has been happening associated with global warming.

  7. "You must realize that it's normal for the pressure near the poles to be lower"?

    Air is sucked into the Vortex from High above (lower than the surrounding pressure) -- near the Surface flows out (higher than surrounding pressure)

    This is similar to a tornado (and water spout)
    which sucks at the bottom and expels on top.

  8. Michio Kaku is auditioning, to be included,
    in the Science Fiction Clown Conferences.

  9. Michio Kaku reminds me of David Suzuki.
    Out of touch.

    For example, Michio Kaku thinks CH4
    might cause warming amplification.

  10. Hey , MIT offers a course on anthropogenic global warming .They call it science. It seems that crackpots took control of MIT .

  11. UK storms caused by warming displaced jet stream? No, says IPCC guy...

  12. "It's mostly a chaotic system controlled by its internal, largely unpredictable processes."

    Processes are not well understood,
    but why give up and call it chaotic?

    Extraterrestrial events drive the system. Wind speeds increase and Jet Streams, move closer to the Equator, in Winter and during Ice Ages. Then, for additional entertainment, Second Law violations.

  13. Perhaps this is more convincing:

  14. Impressive graphics. Sea ice is primarily a function of wind, no?


  15. Processes are not well understood,
    but why give up and call it chaotic?

    Why call it chaotic ? Because it is. And it means in no way "giving up".
    It is just another, much more relevant, paradigm.
    Non linear dynamics (in popular speak chaos theory) aims at dealing with systems which are neither in equilibrium nor in steady state and where the degrees of freedom are coupled in a non linear way..
    And this is clearly a huge majority of what is actually happening in the nature.
    Saying that a system is "chaotic" just means that trajectories in its phase space diverge exponentially with time.
    Navier Stokes hence weather and associated fluid dynamics have this property and therefore ARE chaotic.
    The consequences are well known :
    1) Even if the system is deterministic, e.g obeys some system of non linear PEDs, it is no more deterministically predictable.
    2) Ergodicity is the major question. If the system is ergodic, there exists an invariant probability distribution giving the probabilities of future states. In that sense this is perfectly analogous to QM - only probabilities may be known.
    If the system is not ergodic (typical example of a chaotic non ergodic system are the orbits of N bodies with N>2) then even probabilities can no more be predicted.
    3) The system's orbits in the phase space generally settle on an attractor (topological invariant). Studying the system's dynamics is then equivalent to studying the attractor's topological properties, its stability, its bassin of attraction etc.
    So there is much to be said and studied even about chaotic systems provided one uses the right theoretical tools.
    However predicting exact values of observables describing the system's dynamics doesn't belong to the set of things one can say and study about chaotic systems.

  16. "where the degrees of freedom are coupled in a non linear way" -- nonlinear, as the products if a diode mixer (not chaotic, but the result of inputs)

    "Saying that a system is "chaotic" just means that trajectories in its phase space diverge exponentially with time" -- Then comes down to modeling phase noise?

  17. Year to year changes yes, long-term decline no.