The Kaya is intended only as you say to refer to industrially derived changes in CO2 not the natural ones, of course. I’m not sure what question you think I am missing but if the question is can any set of factors give just as good an idea of causation as Kaya does, then that answer is plainly false. The Puppy-Kaya would state, for instance, that it is impossible for a puppy-free society to have any CO2 emissions whatsoever.

Cheers,

]]>“What is the independent variable exactly?”

The criticism relates to the fact that there isn’t a single independent variable, but there should be for the identity to make sense.

“The Kaya identity simply involves the basic operation of cancellation.”

If so then the procedure is nonsensical as Briggs and others have claimed.

“But, that some readers here outrightly trash researchers’ ideas without thorough understanding is really not admirable behavior.”

What an odd claim. I assume then that you will enlighten us.

]]>There is a discussion of it here: http://wattsupwiththat.com/2014/07/20/lewandowsky-and-oreskes-are-co-authors-of-a-paper-about-enso-climate-models-and-sea-surface-temperature-trends-go-figure/

Short version: If you print this paper on toilet paper, it will be useful.

]]>My question is then how the Kaya identity is a crude type of chain rule expansion that assumes a single independent variable? What is the independent variable exactly?

The Kaya identity simply involves the basic operation of cancellation.

Yes, there is a typo in NIV’s example. Yes, he is also right that those terms are not independent. However, is it possible to decompose CO2 emission or anything else into *variables that are independent of each other? * Or, in statistics, is it possible to observe only explanatory variables that are truly independent of each other?

Johan,

I have no doubt that economists… and climate scientists are faced with many difficulties when trying to sort through complicated situations. But, that some readers here outrightly trash researchers’ ideas without thorough understanding is really not admirable behavior.

I like your comment above.

Sheri,

Yes, indeed, “If it can be destroyed by the truth, it deserves to be destroyed by the truth.” However, as Suntzu said, one cannot win if he doesn’t understand and know his opponents first. If Briggs and you indeed know the truth and understand the climate research, you gotta show it.

Let’s take the following two countries, Austria and Belarus. In the year 2011 Austria emitted 67182180 Metric Tons of CO2; and Belarus 67157810 Metric tons of CO2. That’s almost the same. We call F = CO2 emissions in Metric Tons.

One can easily look up their population (P in Millions); GDP (G in in Billion U.S. Dollars), and their Total Primary Energy Consumption (E in Quadrillion Btu). From that it is easy to calculate GDP per capita (g in thousand U.S. Dollars per capita); energy intensity (e in Btu per U.S. Dollars) and CO2 emissions per unit of energy (f in Metric Tons of CO2 per billion Btu].

For Austria P = 8.217280; g = 40.894340; e = 4386.944790 and f = 45.572266, with F = P*g*e*f = 67182180 Metric Tons CO2, as expected (disregarding rounding errors).

For Belarus P = 9.661510; g= 4.609136; e = 26821.632430 and f 56.227235, with F = P*g*e*f = 67157810 Metric Tons of CO2 (again disregarding rounding errors).

So what can we learn from this? Those two countries do not differ much in terms of CO2 emissions. Belarus is slightly more populated (by a factor of 1.18); and it has higher CO2 emissions per unit of total primary energy consumption, but not all that much (a factor 1.23). But, Austria has a GDP per capita almost 9 times higher than that of Belarus; whereas the energy intensity of Belarus is more than 6 times higher than that of Austria.

How does KAYA help e.g. Belarus in determining their energy and climate change policies? Well, they may try to increase GDP per capita, and hope that energy intensity as a consequence will decrease. Or perhaps they should lower energy intensity, and hope that as a consequence GDP per capita will increase. Or perhaps they should do both. Or perhaps, they should stay poor and nonetheless try to lower energy intensity, who knows? KAYA really does not tell you what to do. It only tells you why two different countries, so similar in some respects, can be very different in other respects.

PS: I hope I got the units correct, as I’m not used to working with Btu.

]]>“I am not sure what the partial derivatives and the number of independent variables have anything to do with the Kaya Identity”

The Kaya identity is a crude type of chain rule expansion that assumes a single independent variable. It is not clear what the variable is but a defence of the identity should identify it and show that all the other terms depend only on it. If there is more than one independent variable, as is almost certainly the case, the chain rule expansion has many terms (paths of CO2 production). NiV gets it although there is a typo in his equation. You must know what independent variables are.

Shawnhet,

“OTOH, if we moved any of the factors in Kaya to zero, it would be pretty reasonable to expect CO2 emissions to drop to zero”

Are you claiming that there was no CO2 before humans entered the scene? Maybe you are interpreting the identity to refer to only changes in CO2 due to industrial society as measured by the ratios given, but that would beg the question. That is why the identity should be explicitly written as rates of change (sinks as well as sources) giving multiple paths tested with empirical data. As it is we have a political and not a scientific or even mathematical identity.

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