As many readers know, there was quite a hullaballo over the Kaya Identity last week, two posts by Willis Eschenbach here and here created sides seemingly equally split on whether the equation is useful or not.
One of the most strident critics was Dr. Roger Pielke Jr., and in the spirit of keeping an open mind on the issue, I offered him space on WUWT. Here is my email and his response, reprinted with his explicit permission.
On Mon, Jul 14, 2014 at 9:52 AM, Anthony xxxxxxx@xxxx.com wrote:
Hello, Roger Jr.,
I’d like to direct you to a comment on WUWT that challenges your calculations using the Kaya Identity.
http://wattsupwiththat.com/2014/07/12/the-beer-identity/#comment-1685623
I provide it only for your information.
I know both of you have issues with the current state of discussion on WUWT regarding that equation/identity/relationship, and I’m certainly OK with that.
I think that much of the dissent over it has to do with the difference in viewpoints between science and engineering. I and many others look at the Kaya identity equation more from the engineering perspective, and expect it to perform as many other calcs do, but it seems that it doesn’t act as a hard equation, but more like a soft one, that generally defines the relationships of terms. A number of commenters have approached it from the engineering viewpoint, and find themselves puzzled as to why the numbers they get don’t seem sensible.
I puzzle over that also.
To that end, and because you’ve been highly critical, agreeing with such statements as “breathtakingly ignorant”, therefore, given the critical comment above, I’d like to offer this, first raised in another comment:
http://wattsupwiththat.com/2014/07/12/the-beer-identity/#comment-1684325
Perhaps Anthony could give equal time to Pielke in defense of the Kaya identity?
I’m more than happy to do so should you be so inclined; not just for my own education on the topic, but for the hundreds, if not thousands of others that suffer from the same doubts that the equation isn’t as well thought out as some claim it to be. Or, if it was never intended to produce real world numbers accurately, but serves only to illustrate the relationship of the variables, explain that clearly so that the engineering types understand it better.
If you wish to make a submission, MS Word with embedded images works best. Any equations you might want to use in MS word’s equation editor don’t translate to WordPress well, so they will be converted to images. Or, you can optionally use LaTex, which is supported directly in WordPress.
I would appreciate an answer, no matter if it is a yes or a no. Thank you for your consideration.
Anthony Watts
=========================================================
Roger’s response Tuesday, July 15, 2014 6:59 AM (published with permission)
Hi Anthony-
Thanks for your email. Apologies for the delay in responding, as have been off email while traveling.
If you’d like to help your readers better understand the use of the Kaya identity, which I think is the most important tool for analyzing actual and proposed carbon policies, then I would recommend that you introduce them to this paper (open access);
http://iopscience.iop.org/1748-9326/4/2/024010
The mathematics are simple. Of course, there is a more in depth discussion in my book, The Climate Fix.
Finally, for those who’d prefer a lecture format, here is me at Columbia Univ last summer explaining the significance of the Kaya Identity for climate policy analysis:
Thanks, and all the best,
Roger (Jr.)
==============================================================
I agree with Roger that: “The mathematics are simple.”
In fact I think it is that simplicity that lends itself to being criticized as not being fully representative of a complex system. Willis described the Kaya Identity as being “trivially true” while Roger in his book and video treats its with the same respect as some physical law equation. My take is that the truth is somewhere in the middle between those viewpoints.
Whether it is best used as a political tool or as a physical science tool is still an open question in my mind, though I tend to think it leans more towards political usefulness. Whatever your viewpoint is, let’s thank Roger Pielke Jr. for taking the time to respond and to offer his view here.
kim LOL I can remember the tune vaguely but not the words. I’ll just hum it.
maybe it’s a “soft’ equation cuz – unlike 6=2*3 and E=MCsquared – the Kaya factors – population, gdp per capita, etc – are cherry picked to “guide” policy makers – the righthand side doesn’t emerge from a rigorous set of equations leading up to them – instead someone used common sense to produce them – or used their agenda
the usefulness of this equation is that it shows policy makers how tweaking any of the chosen factors will effect the lefthand side of the equation – and that’s why the equation is so simple – it shows only the cherry picked factors – and allows them to be tweaked – it can be said to almost state the obvious
i don’t know if alternate factors can be found to make a new and improved guide for policy makers – Kaya kinda works as long as it is never used in isolation – policy makers need to know effects outside of co2 output
M Simon says: (July 18, 2014 at 11:13 pm) “This is a statistical calculation that indicates that ocean cycles and solar activity can explain most of climate. [link]“. It’s pretty, but it’s only a statistical calculation, and it has only been tested over the ~160yr period that was used to derive it. ie, it hasn’t really been tested. The real-world climate has proved to be a graveyard for hypotheses that work for a while but then collapse. (As the IPCC and others keep saying, it’s a complex coupled non-linear system). It will be interesting to see how this one goes over the next few decades – and more. At least it’s going a bit better than the CO2 hypothesis, which looks like it’s well on the way to collapse (rising CO2, not-rising temperatures). If solar activity and the ocean cycle fall together, I fervently hope that it fails!
I hear people saying that skeptics are acting like alarmists. Or are skeptics and alarmists acting like… people?
http://www.nytimes.com/2011/06/15/arts/people-argue-just-to-win-scholars-assert.html
Mike Jonas says: July 18, 2014 at 10:39 pm
“RobertInAz – Willis got it right. The equations are circular logic.”
In which case, every identity that forms the basis of modern physics is circular logic.
You make the same error as Willis when you say: “So the exact same number that goes into the ‘top’ of one equation goes into the ‘bottom’ of the next equation.” The correct description is: “The units of the variable at the top of one term of the equation are the same as the units of the bottom of the next term of the equation. In physics, we confirm our equations are right when the units on the right cancel out to equal the units on the left.
Let’s break down Willis’s wildly incorrect description of the identity term be term: the entire statement was “where “CO2 emissions” are the CO2 emissions of say a given country; “Population” is the population of that country; “GDP” is gross domestic production of the country, which is the total value of all the goods and services produced; and “Energy” is energy consumed by the country.”
1. where “CO2 emissions” are the CO2 emissions of say a given country;. CO2 Emissions on the left are the CO2 emissions of, say a given country The CO2 emisiions term on the right is the CO2 emission for a given unit of energy production. The CO2 term on the right is much smaller. Both terms can be expressed as KG CO2 – the basis of the confusion,
2. “Population” is the population of that country; This is true for the first term. Population in the second term refers to a single person. Again, these are entirely different things that have the same unit of measure – people.
3. “GDP” is gross domestic production of the country: Again, true for the first appearance of the term. For the US, this is trillions of dollars. For the second appearance of the term, it refers to a single dollar. Again, the units are the same (dollars) but the terms refer to completely different things.
4. “Energy” is energy consumed by the country.”. Same store, the first use of the term is a really big number (terrawatts), the second use of the term is a single watt. Once again, the units are the same but the meaning of each appearance of the term is different,
I see the ambiguously framed equation is on 12 of the report Willis referenced. It should have been written like this:
Total CO2 = Total Population * (GDP (dollars)/Person) * (Energy (watts)/ dollar GDP) * (Gram CO//Watt)
That said, if you insist on wrongly interpreting the Kaya identity as did Willis, then you will reach the same conclusion – it is uninteresting,.
In defense of the report, the description immediately before the ambiguous equation was correct:
“we simply refer to them as CO 2 emissions. CO 2 emissions can be expressed as the product of four inputs: population, GDP per capita, energy use per unit of GDP, and CO 2 emissions per unit of energy: “
A recent study shows that people concerned about climate warming use more electricity than the rest of us so the quick solution is to ban communicating climate alarmism.
http://www.telegraph.co.uk/earth/greenpolitics/10965887/People-who-claim-to-worry-about-climate-change-use-more-electricity.html
JamesNV says (at 11:46 pm):
I hear people saying that skeptics are acting like alarmists. Or are skeptics and alarmists acting like… people?
http://www.nytimes.com/2011/06/15/arts/people-argue-just-to-win-scholars-assert.html
= = = = = =
Some people argue just because they don’t enjoy living in a world of extraordinarily popular delusions, with the ruling caste of “movers and shakers” and “opinion makers” always herding us into their shearing sheds or abattoirs. Some people argue for the opposite reason, of course, and they have the loudest voices.
Let me try again:
1. where “CO2 emissions” are the CO2 emissions of say a given country;. CO2 Emissions on the left are the CO2 emissions of, say a given country The CO2 emisiions term on the right is the CO2 emission for a given unit of energy production. The CO2 term on the right is much smaller. Both terms can be expressed as KG CO2 – the basis of the confusion,
2. “Population” is the population of that country; This is true for the first term. Population in the second term refers to a single person. Again, these are entirely different things that have the same unit of measure – people.
3. “GDP” is gross domestic production of the country: Wrong! First appearance is GDP for a single person. For the second appearance of the term, it refers to a single dollar. Again, the units are the same (dollars) but the terms refer to completely different things.
4. “Energy” is energy consumed by the country.”. Wrong! First appearance is Energy per dollar of GDP, the second use of the term is a single watt. Once again, the units are the same but the meaning of each appearance of the term is different,
Because that happened the rest of Willis’ initial article had to be accepted as uninformed. It never got better from there. As strange, his misunderstanding seemed to be the prevalent take on the identity. Not many got it right. It’s happening again in this thread, too.
I do question the value of the entire enterprise given that the presumption of it is more CO2 is bad. We don’t know that, yet.
Khwarizmi, that’s a nice sentiment. But it is clear from recent nasty infighting, that as a group skeptics are no less human than the warmists. As a whole, I wonder how much this kind of primitive behaviour holds humanity back.
I remember how disappointed I was by Roy Spencer’s unfair attacks on Willis. Sigh.
Donald L. Klipstein:
You make two proposals in your post at July 18, 2014 at 9:55 pm and the first is
I have repeatedly pointed out that rhis is what the Kaya Identity is really about. In the previous thread I wrote at July 14, 2014 at 5:40 am in this post.
And your claim that this “means no need for people to die until they do so from old age” is disingenuous because it would ensure they dies of “old age” at a younger age.
The matter is explained in my rebuttal of Malthusianism which is here. I ask you to read it.
Richard
V= s/t or F=ma or etc. are not like the Kaya’s identity. These equations are at their simplest form, and relate different QUANTITIES. The Kaya’s identity is NOT at it’s simplest form; when it is, it is a tautology, A=A. It says nothing. As analytic philosophers say “it is meaningless and should never have been uttered.”
Dimensional analysis is not made with UNITS and it is not made with QUANTITIES. Dimensional analysis is made with QUANTITIES DIMENSIONS (see Wikipedia “List of Physical Quantities”).
In dimensional analysis, V= s/t (and all other correct equations), after you replace quantities with the quantities dimensions, must yeld the same dimension on each side of the equation or, to be simple, must be tautological to be dimensionally sound.
Simplifying Kaya’s identity to get a tautology is simplifying an equation, not dimensional analysis.
Otherwise, anyone can write nice innovative equations which also are meaningless.
Speed = exp(log(Speed)) * (Trains / Boats) * (Boats / Cows) * (Cows / Trains)
Sorry. As I said before, I did this when I was ten to amaze friends.
The most fundamental question, taken as a given assumption by the KId, is that reduction of man’s CO2 emissions can effect global temps. That is specified by RP Jr., that 450ppm =’s +2C by 2100. And that that 50 ppm, above todays 400ppm, comes from man, and thus can controlled by man.
My retort is simple, BS. The sun and its irregular rhythms, the ocean-atmosphere cycles, and their nonlinear feedbacks, with the biosphere and ocean chemistry responses means that man’s ifluence is secondary or tertiary. Natural climate varibility due to factors beyond our control most likely swamp those things within our control. Thus decarbonization of world economies is a fool’s game.
It seems that atmospheric CO2 concentration is a proxy for wealth and growth. No wonder the watermelons don’t like it.
The problem is most people don’t seem to realize that 6=(6/2)*2 is as much an identity as is y= (y/x)*x; where 6 and 2 are obviously just “numbers”; and where y and x are “variables”. In other words, an identity does not have to contain variables !
The KAYA identity is trivially true when using “historical values” (i.e. “just the numbers”) for CO2 emissions, population, GDP per capita, energy consumption per unit GDP and CO2 emissions per unit energy.
The real problem begins when KAYA is used as y = x1 * x2 * x3 * x4, where y = CO2 emissions, x1 = populaton, x2=GDP per capita, x3 energy consumption per unit GDP and x4 is CO2 per unit energy; AND where y, x1, x2, x3 and x4 are now all treated as variables. It does not take a genius do understand this is NO LONGER an identity! You cannot take an arbitrary value of y (CO2 emissions), and expect that for whatever values of x1, x2, x3 and x4 the LHS = RHS.
Once you consider y as an independent variable, and x1, x2, x3 and x4 as dependent variables, you are treating the KAYA “equation” as some kind of “model” that allows you to calculate future values of y, based on some “assumed” values of x1, x2, x3 and x4. But such kind of model is totally detached from reality, for a number of quite obvious reasons. Firstly, it’s an oversimplification (just 4 variables to describe a very complex reality!). Secondly, and more importantly, none of those variables on the RHS are independent of each other (e.g. GDP per capita would more likely than not be some kind of function of Population; not to say that Population in the long run might as well depend on GDP per capita). And accepting that there are dependencies between x1, x2, x3 and x4, there are absolutely no reasons to expect that those dependencies would have to be linear, on the contrary!
In conclusion. The KAYA identity used with historical values is trivially true; KAYA used as an equation to “predict” or “prognosticate” future values of CO2 emissions is an abomination.
To invert Forest Gump’s famous maxim, “Intelligence is as intelligence does”.
In that spirit, the process through which a number of posts have materialised here, from either side of the ‘argument’, could best be described by the cautionary phrase, “Ready, fire, aim!”
Johan says: July 19, 2014 at 2:03 am
Correction, I of course mixed up independent and dependent variables !
Great if people can use it (kaya) as a mental crutch or whatever, to remember that (co2=emissions=energy=money=production)*p/p
Kaya also tells us there where no people on earth 300 years ago.
I guess Occhams razor no more is as sharp as it used to be.
JEyon says:
July 18, 2014 at 11:32 pm
“maybe it’s a “soft’ equation cuz – unlike 6=2*3 and E=MCsquared – the Kaya factors – population, gdp per capita, etc – are cherry picked to “guide” policy makers – the righthand side doesn’t emerge from a rigorous set of equations leading up to them – instead someone used common sense to produce them – or used their agenda”
Well, you’re sort of right about this. The way the right hand side stuff is measured leaves it open to many sorts of errors, but if it was actually flawed we could test it out by double checking against the actual physical measurements of CO2 emissions. This is the step that critics of Kaya never seem to get to which is how the Kaya actually performs (the answer seems to be not perfectly but not bad either).
When I first heard about Kaya my gut instinct was that it couldn’t be very useful but it seems that it does do a reasonable job of modelling CO2 emissions, to my surprise. If, for example, the GDP per capita was unrelated (or inversely related) to CO2 per capita – Kaya would not work in the real world whether or not the units of one side of the equation match the units of the other side of the equation.
Cheers, 🙂
Since Anthony pointed out this post, I think it is worth discussing in a bit of detail.
“http://wattsupwiththat.com/2014/07/12/the-beer-identity/#comment-1685623”
“1. If
c= 2, g=20, p=4, e=8.
Then
RHS = p x (g/p) x (e/g) x (c/e) = 4 x (20/4) x (8/20) x (2/8) = 4 x 5 x 0.4 x 0.25 = 2
Therefore CO2 Emissions = 2 if c= 2, g=20, p=4, **e=8**.
2. If
c= 2, g=2000, p=4, e=8. (Increasing g)
Then
RHS = p x (g/p) x (e/g) x (c/e) = 4 x (2000/4) x (8/2000) x (2/8) = 4 x 500 x 0.004 x 0.25 = 2
Therefore CO2 Emissions = 2 if c= 2, g=2000, p=4, **e=8**”. Emphasis mine.
As you can see above, this approach is based on saying you can have whatever GDP you want providing you can increase GDP without increasing energy (e remains 8). The problem with this is that it can’t be done in the *real world as it exists currently*. For now, if I want to buy a toaster (and increase GDP by doing so) it takes energy to acquire the materials to make, energy to manufacture it, energy to move it to the store and energy for me to move it back from the store to my kitchen.
This example doesn’t reflect the real world.
Cheers, 🙂
M Simon says: I can do that. F=ma
That sounds good until you mix it with politics and everything goes wrong. I have an example.
In the UK we have a 12 ft.lbf legal limit on the permitted power for an unlicenced pneumatic rifle. The accepted formula for calculating muzzle kinetic energy is velocity squared times projectile mass in grains, avoir dupois, all divided by the magic number 450240 and there lies the rub. Obviously to convert pounds mass to pounds force you have to stand somewhere and drop something. To get 450240 you have to stand somewhere where gravity is 32.16 ft/s/s. Beats me.
Obviously science disagrees with the accepted norm. Try to decide which is correct and you end up having Pilates’, “What is truth?” argument. If you are programming for MKE do you want to spend eternity explaining why you are right and 450240 is wrong? No, you use 450240.
If this Kaya thing is for policy makers perhaps we simply render unto Caesar that which is Caesars’ and agree even though it is complete bunkum and tosh.
I tend to infuriate people, if this post infuriates you I apologise, I will try to understand but it is difficult for me, please define your precepts.
Dr. Pielke is a man one can respect. He is not strident and is well reasoned in his arguments. However in this instance, he is also wrong.
What really beats me, even none other than IPCC itself admit that at best,KAYA can only be used to organize discussions of the primary driving forces of CO2 emissions
[QUOTE] While the Kaya identity above can be used to organize discussion of the primary driving forces of CO2 emissions and, by extension, emissions of other GHGs, there are important caveats. Most important, the four terms on the right-hand side of equation (3.2) should be considered neither as fundamental driving forces in themselves, nor as generally independent from each other. [/QUOTE]
http://www.ipcc.ch/ipccreports/sres/emission/index.php?idp=50