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.
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No, Willis is wrong, maybe not even wrong. If population doubles and the rest (GDPpc, energy intensity, emission intensity) stays the same, emission doubles, by definition.
Edim says: “No, Willis is wrong. If population doubles and the rest (GDPpc, energy intensity, emission intensity) stays the same, emission doubles, by definition.”
No, you are wrong.
1. Nothing else “stays the same” if population doubles (duh).
2. The Kaya Identity DOES NOT ALLOW you to double population without changing anything else.
C = P * (G/P) * (E/G) * (C/E).
Double P
C = 2P * (G/2p) * (E/G) * (C/E).
No change in “C”. The 2 in the numerator divided by 2 in the denominator leaves 1, the multiplication identity.
And that is exactly correct! If you were to “suddenly” double the population, they would share the same productivity, or in other words, GDP divided among twice the people!
Incredibly, the Identity does actually work — it shows that tinkering with “just” population isn’t going to work, neither changing “just” GDP.
The only independent variable is “C” so if you want less “C” well then just make less of it.
Curious George says: July 21, 2014 at 7:27 am
“Edim dear, Robert dear, put numbers directly in Kaya. Willis is right.”
Before:
Total CO2 = 100
Total population = 10
GDP/Person = 10
Energy/GDP = 1
CO2/Energy = 1
100 = 10 * 10 * 1 * 1.
Total population = 20
GDP/Person = 10 (unchanged – GDP doubles)
Energy/GDP = 1 (unchanged – Energy use doubles)
CO2/Energy = 1 (unchanged – energy efficiency remains constant)
200 = 20 * 10 * 1 * 1.
In order to get this wrong, you have to very carefully ignore the text that accompanies the ambiguous formula and you have to studiously ignore the many explanations in this thread about what Kaya means.
So yes. If you continue to insist on ignoring reality – then Willis is right.
RobertInAz says “In order to get this wrong, you have to very carefully ignore the text”
Actuallly, you have to ignore the formula/identity or whatever one wants to call it.
Using your example, but the Kaya Identity, you start with
Before:
Total CO2 = 100 (C)
Total population = 10 (P)
GDP/Person = ? Cannot be determined but lets say GDP is 100 so 100/10 = 10 (G/P)
Energy/GDP = ? Cannot be determined but lets say Energy (E) is 100 so 100/100 =1 (E/G)
CO2/Energy = ? This can be measured but is specified as C/E or 100/100 = 1.
100 = 10 * 10 * 1 * 1.
Total population = 20
Total CO2 = 100 (C)
Total population = 20 (P)
GDP/Person = ? Cannot be determined but lets say GDP is 100 so 100/20 = 5 (G/P)
Energy/GDP = ? Cannot be determined but lets say Energy (E) is 100 so 100/100 =1 (E/G)
CO2/Energy = ? This can be measured but is specified as C/E or 100/100 = 1.
100 = 20 * 5 * 1 * 1.
As you can see, the Kaya Identity moves some factors around but the result is unchanged. More pop, less GDP per person, all the same!
Ah, but you said not to change any other term — the Kaya Identity does not allow that. If you change population in the first term, why do you not change it in the second term? If you change GDP in the second term, why do you not change it in the third term?
Obviously if “G is not G” and “P is not P” and so on, then you can do anything you like and it will have all the respect it deserves (not much, in other words).
Plainly you are *working* from something that is not the Kaya Identity. Why do you defend the indefensible? Acknowledge that the “identity” is mathematically useless and not even a very good persuader. You and others argue “what if we double population but don’t change anything else”. Well how likely is THAT?
Willis, if you were to pay attention to the conversation you started OR to the actual way that the Kaya Identity is used (see Pielke!), you would know that this is nonsense:
Willis (yesterday, 9:48 pm):
The Kaya Identity starts with the working assumption that each of the ratios remains constant. If CO2 emissions per unit of energy remains constant, then emissions in your scenario would double, of course.
To be sure, as Pielke discusses, the ratios in the Kaya Identity do not remain constant over time. Energy/GDP tends to fall due to both technological change and (what I prefer to call) structural change in the economy. CO2/energy may fall due to both technological change and structural change in energy sources. The Kaya Identity, as competently used, accounts for all this and puts it into a framework that (i) aids our understanding and (ii) helps to identify what might (or might not) feasibly be done to change outcomes. Pielke uses the Identity to show how Britain’s official energy policy cannot plausibly achieve its goals.
Willis, you waste people’s time and show great disrespect when you take uninformed and misguided pot shots at others’ analysis. Please, inform yourself now about how the Kaya Identity is actually used — and put into practice the first rule of holes.
Willis said at 9:48 pm “Here’s my problem with the Kaya Identity …. what happens to the amount of CO2 emitted from doubling [all] those variables? Well … nothing“.
If you take my earlier simplified formula up-thread A/B * B/C * C/A = 1 (which is equivalent Kaya-style to C = B * A/B * C/A) and assume both A and B double in unit time dt, then differentiating by time produces: dC/dt = dB/dt * A/B * C/A + B * d(A/B)/dt * C/A + B * A/B * d(C/A)/dt
where dB/dt = B (it doubles in unit time); d(A/B)/dt (change in A/B in unit time) = 0 (A/B remains the same) and d(C/A)/dt = (dC/dt A – dA/dt C) /A*A where dA/dt = A (again it doublea in unit time), so d(C/A)/dt = (dC /dt – C) / A.
Thus dC/dt = B * A/B * C/A + 0 + B * A/B * (dC /dt – C) / A, giving dC/dt = dC /dt.
So (extrapolating no more than a little to the full “formula”) Kaya actually predicts that the amount of CO2 emitted from doubling all the variables is (drumroll please …) whatever the increase in CO2 happens to be.
I don’t believe this greatly assists either side of the debate …
Willis Eschenbach says:
July 20, 2014 at 9:48 pm
“Now, suppose that the population doubles and the GDP doubles and the energy used doubles. That seems like a very probable change, that in the future we’ll have more people using more energy and producing more stuff.
According to the Kaya Identity, what happens to the amount of CO2 emitted from doubling those variables?
Well … nothing. No change in the slightest. The population and the GDP and the energy used all appear in both the numerator and the denominator, so they cancel each other out. As a result, the conclusion has to be that a doubling of the population combined with a doubling of the GDP and a doubling of the energy used will have no effect on CO2 emissions.”
Heh. Can we really be ~1000 posts in on something that is a simple math mistake?
Let’s take a look at the math:
CO2(1)=2P*(2GDP/2P)*(2E/2GDP)*(2E/2CO2) equation 1
CO2(2)=P*(GDP/P)*(E/GDP)*(E/CO2) equation 2
Divide equation 1 by equation 2 to get the ratio of CO2(1) to CO2(2)
Gives you a ratio of 2:1 (we have one more 2 in equation 1 than gets cancelled out by the ratios).
Cheers, 🙂
D’oh. I flipped the last term in my equations 1 & 2 – should read 2CO2/2E and CO2/E respectively. The rest of my post is still good though.
Cheers, 🙂
Oops – I marked the change in the wrong variable. It is the energy usage per GDP which must magically be cut in half. The principle remains…
I’ll add in numbers to show what I mean (when energy usage and GDP double).
Let’s pick arbitrary values to start with:
GDP = 1000
P = 100
TE = 50
C = 20
So C = 100 * 1000/100 * 50/1000 * 20/50 = 20
Double GDP and P
C = 200 * 2000/200 * 50/2000 * 20/50 = 20
BUT: notice that the third term went from 50/1000 to 50/2000 – the Energy per GDP must be cut in half to hold carbon emissions constant. And that is the whole point of the equation.
“For this toi play, the CO2 efficiency of energy production doubles. So if today, a KW of energy production emits 100 KG of CO2 – in the doubled population/GDP/Energy scenario, it will emit 50 KG of CO2. Kaya tells us this type of progress is implausible.”
The recent EPA regulation limits US power generation to 1,100 pounds of CO2 per MWh, goal is 30% CO2 reduction, 2.2% of global total. Oh, boy!!
My back of the envelope has coal/steam at about 2,200 lb/MWh, NG/steam at about 1,100 lb/MWh, simple CT at around 1,100 lb/MWh, NG combined cycle at around 600 lb/MWh. It’s all about efficiency, aka heat rate. A major shift away from coal to NG and CC is not only plausible, it’s a happenin’ raht now!
NG produces about half the CO2 per Btu as coal, bur twice the water vapor!
Observed a fracing operation in 1967 as an summer engineer & it wasn’t news then.
Mike Tremblay says:
July 20, 2014 at 11:25 pm
Firstly I see that we agree on a lot.
1. We agree that some of the plant material which would grow in the wild if we produced less food would rot and release the carbon back to the atmosphere.
2. We agree that it takes some time from the carbon capture in the photosynthesis to the rotting and that this time is highly dependent on the type of vegetation.
3. We agree that some fraction of the plant material will not rot; it will sink in anaerobe sediments and eventually grow new fossil carbon.
What we may disagree on is the amounts and the times. I think the fraction in 3 is so small that we can count it out of the equation. I don’t have the numbers for that, but it would surprise me if it is more than 1 percent.
So let us count out 3 and concentrate on 1 and 2.
You claim that the rotting process takes from decades to millions of years to bring back the CO2 to the atmosphere. I do not think so because you would then have seen all the carbon stored on those places. If it had taken two decades for grasslands to rot the grass, you would have found the two decades of dead grass in the soil. Likewise if it has taken a million year to bring the carbon captured in the jungle back to the atmosphere, you would have found a layer of one million year of plant growth in the jungle soil. You will not find that.
The time from plant growth to plant rotting has to be much shorter than that.
If the time for plants to rot in the wild equals the time from food production to food consumption then there would be a 100% zero sum budget as I described. However, you are probably right that the plant rotting in the wild on average takes a little longer than the time from food production to consumption. I would guess between five and ten years, but that only means that we have a delay in the emissions. I consider a delay in the emissions of less than a decade as quite negligible.
/Jan
The term Kaya Identity should have quotes around “Identity”, as it isn’t actually an identity. It’s simply a definition of a hypothesized functional relation amongst several variables, i.e., it defines what one could call the Kaya Function or Relation. Or one could call it the Kaya Hypothesis. To do otherwise is sloppy jargon.
Michael 2 says:
July 21, 2014 at 2:35 pm
“And that is exactly correct! If you were to “suddenly” double the population, they would share the same productivity, or in other words, GDP divided among twice the people!”
This is only true for “sudden” changes. Real life changes will happen gradually. Doubling the population will create *over time* twice as much demand for stuff, which will require twice as much supply for stuff.
Cheers, 🙂
Shawnhet says “Doubling the population will create *over time* twice as much demand for stuff, which will require twice as much supply for stuff.”
MAYBE. It depends upon the price elasticity of demand as well as simple demand. It could simply lead to scarcity and higher prices (ie, DeBeers diamonds) or *substitution*. DeBeers is a good example since not so long ago demand didn’t exist and has been made to exist solely through advertising.
Eventually you hit Malthusian limits on any commodity where doubling the population simply does not and cannot double the supply. I suspect that to a certain extent all nations on earth are already pushing against this limit. I doubt a nation exists anywhere that can just double its supply of anything to meet the demand of a doubled population.
Conversely, cutting a population in half is not necessarily going to cut demand (and carbon dioxide) in half. The remaining half will simply be more affluent and in fact this is seen in all modern nations with low birthrates.
Already I sense in the United States a lessening of the work ethic, GDP could go down and perhaps already is, simply because today’s youth (certainly my offspring) generally don’t want to work as was done in the 1950’s when post-war industrial capacity was high and depreciation low.
My experience is that when you think it is hard to understand a formula or identity, it helps to put in some figures.
Kaya: C= P*(GDP/P) * (TE/GDP) * (C/TE)
The figures for the world in 2007 are:
Population: 6. 665 billion
CO2 emission per Year: 29.7 billion ton
Energy use: 494 Quadrillion BTU (or 145 000 TWH)
GDP: 63 Trillion USD
This means that the average GDP/Capita was 9550 USD /year
And the average Energy efficiency (TE/GDP) was 2.3 KWH per dollar
And the average carbon intensity of energy was 0.205 Kg CO2 per KWH.
Then we have a framework for estimating how much we must improve energy efficiency or reduce carbon intensity of energy production if we shall reach a given goal for reduction of the CO2 emissions.
If the population doubles and all other factors are kept constant the emissions will of cause also double.
Source: http://books.google.no/books?id=vebDRK0a6OAC&pg=PA130&lpg=PA130&dq=kaya+energy+per+gdp&source=bl&ots=rA6RHsvdRQ&sig=kEx99Im6kmlQBqKVGHVxU32AEoI&hl=no&sa=X&ei=o5bNU4-SOcX-ygP1_YLQAw&ved=0CEMQ6AEwBQ#v=onepage&q&f=false
/Jan
Jan Kjetil
Kaya: C= P*(GDP/P) * (TE/GDP) * (C/TE)
The figures for the world in 2007 are:
Population: 6. 665 billion
CO2 emission per Year: 29.7 billion ton
Energy use: 494 Quadrillion BTU (or 145 000 TWH)
GDP: 63 Trillion USD
And you get C = C.
It’s a good thing you already knew “C” — 29.7 billion tons!
Let’s cut population in half. It’s in the numerator and denominator — no change!
Lets cut GDP in half. It’s in the numerator and denominator — no change!
Cut C02 in half — success!
“If the population doubles and all other factors are kept constant the emissions will of cause also double.”
No. But let’s try it, simplifying the numbers a bit, using “terms” instead of “factors”. Up until now, chaging a FACTOR, such as population, is instantly and immediately canceled in the next TERM.
So — doubling P, but keeping the next TERM at the same RATIO, requires to double GDP (not that you or I can actually do that, this is a theoretical exercise).
And if you double GDP, and you want the third term to maintain ratio, you must double TE. Good luck with THAT.
And if you want the fourth term to remain the same, you must double CO2.
And because it is a tautology or identity, you double what you started with. Thus, it doesn’t matter what it is, you must double it — but only in the scenario that you really think you can double GDP and Total Energy.
In practice doubling population will approximately halve the per-capital energy (and DP) depending on where you live.
In practice you have really just doubled energy production with its attending carbon dioxide. The other terms are irrelevant.
Michael 2 says: July 21, 2014 at 2:39 pm
“I had no idea how few people can work ordinary algebra, or lay something out that deliberately looks like algebra but we are assured that it isn’t (you could, of course, lay it out differently so that it means what you seem to think it means).”
Michael,
You and illis and a few others continue to interpret the formula on page 12 of the report in a way that is different from the immediately preceding text. To repeat that text one more time (it is on page 12). 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: .
The following formula does not reflect this text:
CO 2 emissions = Population x (GDP/Population) x (Energy/GDP) x (CO 2 /Energy)
It should read
Total CO2 emissions from energy production =
Total population * (GDP/Person) * (Energy / GDP Unit) * (CO2 Units / Energy Unit)
That is what the text says. These two formulas are different. Willis keeps pulling up the ambiguously framed formula and does not understand or fails to acknowledge the difference between the formula and the text.
That said, the correct formula can be re-framed less usefully as:
b> Total CO2 emissions from energy production =
Total population * (Total GDP/Total population) * (Total Energy / Total GDP) * (CO2 Units / Energy Unit) and you can cancel to get
b> Total CO2 emissions from energy production = (Total Energy ) * (CO2 Units / Energy Unit)
But you cannot cancel out total energy against the Energy Units variable in the CO2 efficiency of energy production term. Energy Unit is simply a unit of measure.
The proper Kaya formulation is more useful because focusing solely on the CO2 efficiency of energy production term has unfortunate side effects such as also decreasing GDP.
Robert says: “To repeat that text one more time (it is on page 12).”
You can re-read mine a few times too.
“continue to interpret the formula on page 12 of the report in a way that is different from the immediately preceding text.”
Well there you go. You ignore the obviously flawed formula that doesn’t capture the meaning of the text. But it *is* that formula that is on display for a bit of ridicule. Laugh at it with the rest of us. It’s amusing and it draws a lot of attention to the “text”. There’s no such thing as bad press.
As to the problems in the text, others have discussed them at length according to how important each term is to them personally. Yours (and mine) is on the energy term — the only thing directly amenable to change, and also the only thing that can be accurately measured. It should not be calculated, it should be MEASURED and suddenly the tautology vanishes (so do the other terms but they were never there).
Michael 2 says:
1. Nothing else “stays the same” if population doubles (duh).
2. The Kaya Identity DOES NOT ALLOW you to double population without changing anything else.
Michael, these are Willis’ conditions:
P(2) = 2P(1), G(2) = 2G(1), E(2) =2E(1)), C(2) unknown.
C(2) = 2P * (2G/2P) * (2E/2G) * (C(2)/2E) and canceling out:
C(2) = C(2).
This is undetermined and it cannot be said what happens to CO2 emissions – we don’t know what happens with the emission intensity (C/E). However, assuming the same emission intensity (the same fuel mix or the same carbon content of the average fuel mix), the emission doubles. If the emission intensity is 50% lower, then nothing happens to CO2 emissions (2*0.5 = 1), in spite of the doubling of population, GDP and energy used (Willis’ conditions). In fact, in this case, the doubling of energy used is enough information – population and GDP is irrelevant if we already know the energy used (E) and its CO2 emission intensity (C/E).
This is exactly why the Kaya Identity is useful – you can analyze the factors that influence the change in emissions (emission intensity, energy intensity, GDP per capita and population).
Michael 2 says:
Oh? How did you happen to become Keeper of the Table?
Just an informed opinion. We *are* talking about government here. They have to be seen to do *something*. One thing to consider is how all these people are going to save face when it finally becomes apparent to everybody that CO2 wasn’t such a big issue after all.
In case that isn’t clear to Jan Kjetil and others —
The proposal is to *constrain the ratios* so that if you double any of them you must double all of them and
C = C
becomes
2C = 2C.
There’s nothing in the formula that suggests anything is constrained, and there’s nothing in real life to suggest you CAN constrain any of the ratios.
Michael 2 says:
July 21, 2014 at 6:02 pm
“MAYBE. It depends upon the price elasticity of demand as well as simple demand. It could simply lead to scarcity and higher prices (ie, DeBeers diamonds) or *substitution*. DeBeers is a good example since not so long ago demand didn’t exist and has been made to exist solely through advertising.”
I don’t really disagree with you here but remember the context of your original point – that raising the population would somehow be constrained to keep the GDP the same. Your argument would only work if the price elasticity was non-existent (ie the demand can’t change). IOW, your assumption is highly unrealistic.
“Eventually you hit Malthusian limits on any commodity where doubling the population simply does not and cannot double the supply. I suspect that to a certain extent all nations on earth are already pushing against this limit. I doubt a nation exists anywhere that can just double its supply of anything to meet the demand of a doubled population.”
The fact that GDP is growing globally argues pretty strongly against Malthusian limits having any practical limiting factors on the economy. Furthermore, the constant dollar cost of almost all commodities is falling even while GDP and population are both rising. Fact is, commodities are becoming less and less important to GDP.
Cheers, 🙂
Shawnhet says “The fact that GDP is growing globally argues pretty strongly against Malthusian limits having any practical limiting factors on the economy. Furthermore, the constant dollar cost of almost all commodities is falling even while GDP and population are both rising. Fact is, commodities are becoming less and less important to GDP.”
Thank you for an intelligent conversation that could actually go somewhere.
In this case I detach “GDP” from resources. Malthusian limits have nothing to do with the labeling of resources with dollar values. GDP will rise simply because of inflation if for no other reason, it is a measure of *activity* and not of resources. It’s artificial and a poor metric of anything long term because its “basis” changes. I recognize that you normalize GDP to a standard dollar and I appreciate your recognition of the importance of doing so.
I suggest it is also important to not compare a regional process and a global process although I’ll admit to sometimes doing just that to provoke a discussion. In this case, “population rising” is a global phenomenon but not particularly a regional phenomenon, not in the places where GDP is rising (IMO – more specificity would help). China, having both a rise in GDP *and* Population, achieves this as partly a rebound from the Cultural Revolution and also a massive application of the energy subsidy of coal. The United States seems to have had a substantial decline in GDP a couple of times in the past decade while its population (excluding recent immigrants) is somewhat steady.
Stated another way, a hyperinflated nation will have soaring GDP on the books, and obviously the per-capita GDP will also soar — but what is actually changing? That nation is sinking! But if we stipulate that all GDP will be in Standard Dollars then it would be more useful.
Consider Norway — abundant hydropower. That entire nation is practically disconnected from the Kaya Identity. Population? Irrelevant. GDP? Irrelevant. CO2 production per Kilowatt? Nil.
At the other extreme is a poor African nation — Population high, GDP extremely low, CO2 production per kilowatt? Hard to say when there’s no kilowatts — but they make plenty of CO2 from burning charcoal, wood, and dung.
It seems trivially easy to portray the *intention* of the Kaya identity in a way that does not expose it (and its advocates) to ridicule. Why do so many people not see this? Some here have attempted that very thing but it’s not “sticky”. Once you make a Kaya formula “rational” it is rather mundane and obvious — leaving the spotlight on the absurdity.
So what can each nation decide to do?
Pol Pot succeeded nicely with population reduction, so did Lenin and Josef Stalin. Reduce GDP? Many nations can do that simply by meddling in the market or inserting a “deadweight loss of taxation”. How about simply mandating how much CO2 can be emitted? Obama’s EPA is going down that road and we will see how it goes if and when New England is cold and dark in the winter and Democrats have to choose between light and heat and party purity.
I originally agreed with Willis that it seemed a trivial identity, but then I went and read how Dr. Pielke was using it here. I see it now as an heuristic formula to put the scope of lowering emissions to the degree advocated into perspective. It looks useful for that purpose.
When you keep going around in circles … fly off on a tangent:
What is the humane way to reduce population in third world countries? Assuming you want to (to reduce CO2, of course). Give them a TV set and the electricity to run it.
http://conservationmagazine.org/2013/09/tv-as-birth-control/
There’s more emergent wisdom in here than in a psuedo-deterministic “identity”.
Michael 2 says:
July 21, 2014 at 5:48 pm
Michael 2, the Kaya identity does not work that way.
The Kaya Identity starts with the working assumption that each of the ratios remains constant
Do you really think scientists are that foolish?
/Jan
Jan Kjetil Andersen “Michael 2, the Kaya identity does not work that way.”
I sit corrected. Who in their right mind would assume that just because it looks like algebra and is being used in science, that it is indeed algebra being used in science?
“Do you really think scientists are that foolish?”
I’m starting to arrive at that conclusion. The foolishness is persisting in defending a thing that any 8th grader on the math track can see is absurd.
I use Ohm’s Law: E = I * R. This can be restated such that I = E/R, and R = E/I.
Thus: E = (E/R) * (E/I).
At least it doesn’t cancel out (E stays in the numerator all the way across).
But you have the problem of the unknown quantity appearing on both the left hand side and the right hand side.
The Kaya Identity is sold to the public as a way to calculate total CO2 emissions. Obviously it does no such thing. It is also sold to the public as a way to express the various factors that contribute to CO2 emissions. Because of the self-canceling nature of the formula it doesn’t even do that, and there’s no limit to the number of terms (and their irrelevancy) and arrive at the same conclusion.
Still, I can see where the Kaya Identity should inform policy in the sense that ACTUAL changes in population probably will actually cancel out — double the population and each person is going to get half the resources with negligible impact on CO2 emissions.
But scientists, or at least the people HERE advocating for it, say that I must double the population — then double the GDP to keep the ratio the same — then double the energy to keep the next ratio the same — then finally double the CO2 to keep the fourth ratio the same.
So what actually is the GOAL? The goal is to keep the ratios the same. It seems to have very little to do with reality.
Michael 2 says: July 21, 2014 at 5:48 pm
Kaya: C= P*(GDP/P) * (TE/GDP) * (C/TE)
Yet again. . This is not Kaya. This is yours and Willis’s misunderstanding. Again, the full context from the article Willis quotes.
The simplest way to describe the deep decarbonization of energy systems is by the principal drivers of energy-related CO 2 emissions—for convenience, since the focus of this chapter is on energy systems, 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:
CO 2 emissions = Population x (GDP/Population) x (Energy/GDP) x (CO 2 /Energy)
The words are correct. The formula which you and Willis constantly reproduce, is wrong.
PLEASE READ THE WORDS
Michael 2 says: July 21, 2014 at 5:48 pm
Kaya: C= P*(GDP/P) * (TE/GDP) * (C/TE)
And for the readers who have not been following this thread, the critical error is bolded above. You can apply the incorrect interpretation to the other terms and get correct answers. Interpreting the last energy term as total energy is what leads to all of the confusion.
The last term is CO2 per unit of energy. It is the CO2 efficiency of energy production. Interpreting the last term as total CO2 over total energy is what leads to the C=C conclusions. People can certainly do that since that was the formula in the text, put that is not Kaya. It is something else.
RobertInAz says “Interpreting the last energy term as total energy is what leads to all of the confusion.”
It requires no interpretation. If the denominator of the last term is the same as the numerator of any other term then it makes no difference if you have E/E or TE/TE.
“The last term is CO2 per unit of energy. It is the CO2 efficiency of energy production. ”
Indeed it is. I get that and I suspect so do most people here. That’s not what is *written* however and it is the written formula that provides sport. It’s about time the “deniers” get to have a little sport!
Michael 2 says: July 22, 2014 at 8:22 am Indeed it is. I get that and I suspect so do most people here. That’s not what is *written* however and it is the written formula that provides sport. It’s about time the “deniers” get to have a little sport!
The “sport” thread is here: http://wattsupwiththat.com/2014/07/12/the-beer-identity/
This is where you, Willis and others can wax lyrical about the not-Kaya formula.
This thread is supposed to be about Kaya. You are hijacking it because the beer identity thread is an exercise in naval gazing.
[Rather “Navel gazing”, right? 8<) .mod]
RobertInAz says “This thread is supposed to be about Kaya.”
And so it is — all 299 comments!
If you are attempting to apply the Kaya Identity to real world data and keep coming up wth CO2 = CO2 then take that as evidence you are doing it wrong and need remedial help to understand exactly what is implied by a mathematical identity and how they are used. Accept this as fact: Willis got it wrong. Don’t emulate his example. Pielke Jr got it right – give that a try.
dp says “keep coming up wth CO2 = CO2 then take that as evidence you are doing it wrong”
I think I am glad you were not my algebra teacher in middle school, for that is exactly what I get every time I work it.
“Accept this as fact: Willis got it wrong. Don’t emulate his example. ”
I do not accept words on my computer screen as fact. I accept them as hints, more or less, which if I find interesting I can study primary resources where that is possible.
An “identity” doesn’t have constraints. But many here insist that the Kaya Identity DOES have constraints, you cannot change any of the ratios BUT you can still change population. That’s not math. It’s a mind game following your rules and arriving at a conclusion that the rules guarantee. That’s not my game. It’s yours.
RobertInAz says:
July 22, 2014 at 4:18 am
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:
CO 2 emissions = Population x (GDP/Population) x (Energy/GDP) x (CO 2 /Energy)
—-
RobertInAz –
what am i getting wrong
it seems to me that GDP in (GDP/Population) is not the same as GDP in (Energy/GDP) since the latter is “unit of GDP”
thanks
–john eyon