Diving into the Deeps of Decarbonization

[UPDATE: Comment from Anthony: There has been a tremendous amount of discussion and dissent on this topic, far more than I ever would have imagined. On one hand some people have said in comments that Willis has completely botched this essay, and the Kaya identity holds true, others are in agreement saying that the way the equation is written, the terms cancel and we end up with CO2=CO2. It would seem that the cancellation of terms is the sort of thing that would rate an “F” in a simple algebra test. But, I think there’s room for both views to be right. It seems true that *technically* the terms cancel, but I think the relationship, while maybe not properly technically equated, holds as well. Here is another recent essay that starts with Willis’ premise, where CO2=CO2 and expounds from there. See: What is Kaya’s equation?

Further update (modified 3AM 7/12/14): Willis has posted his response in comments, and due to my own travels, I have not been able to post it into the body of the message until several hours later, see it below. – Anthony]

Guest Post by Willis Eschenbach

pathways to deep decarbonizationAnother day, another new piece of mad garbage put out by the UN. It’s called “pathways to deep decarbonization”, all in lower case (8 Mb PDF). Their proposal is to get CO2 emissions down to zero.  I didn’t get far into it before I cracked up laughing and lost the plot.

It starts with the following definition:

Deep decarbonization requires a very significant transformation of energy systems. The ultimate objective of this transformation is to phase out fossil fuel combustion with uncontrolled CO2 emissions. Only fossil fuels in conjunction with CCS [carbon capture and storage] would remain.

But that wasn’t the funny part. That was just depressing. The funny part came later.

Now, out here in the real world the most charitable way to describe this lunacy of forcing the nations of the world to give up fossil fuels is to … to … well, now that I think about it, there is no way to describe this as anything but a pathetic joke which if implemented will cause untold economic disruption, disaster, and death.

In any case, in order to figure out how to “phase out fossil fuel combustion”, they go on to describe what they call the “principal drivers” of CO2 emissions, viz:

The simplest way to describe the deep decarbonization of energy systems is by the principal drivers of energy-related CO2 emissions—for convenience, since the focus of this chapter is on energy systems, we simply refer to them as CO2 emissions. CO2 emissions can be expressed as the product of four inputs: population, GDP [gross domestic production] per capita, energy use per unit of GDP, and CO2 emissions per unit of energy:

CO2_{emissions} = Population * \frac{GDP}{Population} * \frac{Energy}{GDP} * \frac{CO2_{emissions}}{Energy}

That was where I lost it …

Now, at first glance that looks kind of reasonable. I mean, emissions must go up with population and with GDP per capita, and go down with energy efficiency.

Here’s why I laughed. Lets apply the usual rules of math to that equation. We know that if a variable occurs both on the top and bottom of a fraction, we can cancel it out. Starting from the left, Population on the top cancels Population on the bottom. Then GDP on the top cancels GDP on the bottom. Then Energy on the top cancels Energy on the bottom … and we’re left with …

CO2_{emissions} = CO2_{emissions}

Pretty profound, huh? CO2 emissions are equal to CO2 emissions. Who knew?

OK, now let’s build their equation back up again. But instead of using gross domestic production (GDP), we’ll use gross beer production (GBP) instead.

CO2_{emissions} = Population * \frac{GBP}{Population} * \frac{Energy}{GBP} * \frac{CO2_{emissions}}{Energy}

Note that this is identical to and equally as valid as their whiz-bang equation, in that it simplifies down to the same thing: CO2 emissions = CO2 emissions.

And as a result, the clear conclusion from my analysis is that the best way to fight the evil menace of CO2 is to figure out a way to make beer using less energy …

Now, there’s a carbon reduction program I could get behind.

Best wishes to all,

w.

The Usual Request: If you disagree with someone, please quote the exact words you disagree with. This prevents misunderstandings, and lets us all understand your objection.

PS—Due to a cancelled flight, I’m stuck here in a hotel in LA on my way back from the Ninth International Climate Change Conference, which I’ll write about another time, and sitting in my hotel room wishing I were home. Not much to do but read boring UN documents … at least this one was funny.

PPS—Although it’s not mentioned in the document, their goofy equation is known as the “Kaya Identity“. Apparently, the number of innumerate people on the planet is larger than I had feared.

==============================================================

Willis Eschenbach says:

Well, yesterday was a long day. Up early to get to the airport, and this time the flight actually flew. Go deal with the rental car. Roll on home.

Then change clothes, I’d spent the night without luggage. Hang out with the gorgeous ex-fiancee and catch up. Put in a load of wash. Put the trash in the trash bin, the recyclables in their bin, the kitchen scraps in the garden waste bin. Roll all three of them up the driveway to the street. Unpack. Pack. Wash the dishes. Make coffee. Scrub the toilet.

Then when I got around to opening up my computer in the afternoon, after waking up from its normal sleep and running for about 15 minutes … it died. Dead. As in when I turned it on, It ran for about 5 seconds, and croaked …

So … that meant another 45 minute drive to the “local” Apple store. It also meant about an hour’s worth of waiting for an appointment. Then another three hours while they worked on the machine before finally getting It to run again. Net result?

It’s now 10 PM, and I’m back where I was last night … on line again. Oh, and a couple hundred bucks lighter.

Anyhow, that was how my day went. I hope Bart had more fun than I did.

Regarding the comments, I’m overjoyed that there is much discussion of the issue. My point, albeit poorly expressed given some of the comments, was that since the Beer Identity Is equally as true and valid as the Kaya Identity, it is obvious that we cannot use the Kaya Identity to “prove” anything.

So yes, the Kaya Identity is true, but trivially so. We cannot depend on it to represent the real world, and it can’t show us anything.

For example, folks upstream said that we can use the Kaya Identity to show what happens if the GDP per capita goes up by say 10%. According to the Kaya Identity, emissions will also go up by 10%.

But according to the Beer Identity, if Gross Beer Production per capita goes up by 10%, then CO2 emissions have to go up by 10% … and we know that’s not true. So clearly, neither identity can serve to establish or demonstrate anything about the real world.

What I tried to say, apparently unsuccessfully, is that by itself, the Kaya Identity cannot demonstrate or show or prove anything about the real world. If there is anythlng true about it, that truth must exist outside of the Kaya Identity. Otherwise the Beer Identity would be a valuable guide to CO2 emissions … but we know that’s not true.

Finally, l hear rumblings that Anthony shouldn’t have published this piece of mine. This totally misunderstands Anthony’s position in the game. The strength of WattsUpWithThat is not that it is always right or that it publishes only the best stuff guaranteed to be true.

The beauty and value of WUWT that it is the world’s premier location for public peer review of climate science. On a personal level, WUWT is of immense use to me, because my work either gets falsified or not very quickly … or else, as in this case, there’s an interesting ongoing debate. For me, being shown to be wrong is more valuable than being shown to be right. If someone can point out my mistakes, it saves me endless time following a blind alley.

And indeed, there is much value in the public defenestration of some hapless piece of bad science. It is as important to know not only which ideas are wrong but exactly why they are wrong. When Anthony publishes scientific claims from the edges, generally they are quickly either confirmed or falsified. This is hugely educational for scientists of all kinds, to know how to counter some of the incorrect arguments, as well as giving room for those unusual ideas which tomorrow will be mainstream ideas.

So it is not Anthony’s job to determine whether or not the work of the guest authors will stand the harsh light of public exposure. That’s the job of the peer reviewers, who are you and I and everyone making defensible scientific comments. Even if Anthony had a week to analyze and dissect each piece, there’s no way that one man’s wisdom can substitute for that of the free marketplace of ideas … which is why it’s not his job. Bear in mind that even with peer review, something like two-thirds of peer reviewed science is falsified within a year. And Anthony is making judgements publish/don’t publish on dozens of papers every week.

So please, dear friends, cut Anthony some slack. He’s just providing the arena wherein in 2014 we practice the blood sport of science, the same sport we’ve had for a few hundred years now, ripping the other guys ideas to bits, also known as trying to scientifically falsify another person’s claims that you think don’t hold water. It is where we can get a good reading on whether the ideas will stand up to detailed hostile examination.

It is not Anthony’s job to decide if mine or any other ideas and expositions and claims will wtthstand that test … and indeed, it is often of value for him to publish things that will not stand the test of time, so that we can understand exactly where they are lacking.

So please remember, Anthony is just providing the boxing ring. It is not his job to predict in advance who is going to win the fight. His job is to fill the cards with interesting bouts … and if this post is any example, he is doing it very well.

Best to everyone,

w.

===============================================================

And a final update from Anthony:

While Willis wants to cut me some slack, and I thank him for that, I’m ultimately responsible for all the content on this website, whether I write it or not. While some people would like nothing more than to have content they deem “wrong” removed, such things generally present a catch-22, and cause more problems than they solve. Of course some people would be pleased to have WUWT disappear altogether. Some days, I’m one of them, because it would allow me to get my life back.

The value is being wrong is learning from it. If you don’t learn from it, then being wrong deserves every condemnation thrown at you. I plan on being wrong again, maybe as soon as today, though one never knows exactly when your training and experience will lead you down the wrong path. In this case I was wrong in thinking that this simple terms cancellation argument pretty much made the Kaya identity useless. I’m still unsure how useful it is, or whether its usefulness is mainly scientific or political, but rest assured I now know more than I ever thought I would know about it, and so do many of you. And there’s the value.

I thought this was relevant, and worth sharing:

“For a scientist, this is a good way to live and die, maybe the ideal way for any of us – excitedly finding we were wrong and excitedly waiting for tomorrow to come so we can start over.”  ― Norman Maclean

Thanks for your consideration – Anthony Watts

The climate data they don't want you to find — free, to your inbox.
Join readers who get 5–8 new articles daily — no algorithms, no shadow bans.
0 0 votes
Article Rating
682 Comments
Inline Feedbacks
View all comments
Matthew R Marler
July 10, 2014 4:06 pm

JK: One example of what people want to do does involve estimating the final ratio directly. That is thinking about the effect of changing the the way energy is produced, e.g. what would happen in a future scenario where:
That is way too sensible. Couldn’t you write some jokes or something? You are correct, but not quite in tune with the spirit of the post.

Daniel G.
July 10, 2014 4:13 pm

the variable representing the number of cases is declared as C

C is the number of crates.
For references:
M = C * B/C * P/B * M/P
M&Ms = Crates * Boxes / Crates * Packages / Boxes * M&Ms / Package

David B
July 10, 2014 4:15 pm

For admirers of Willis Eschenbach (among whom I count myself), this is embarrassing.

Daniel G.
July 10, 2014 4:16 pm

Matthew R Marler says:

That is way too sensible. Couldn’t you write some jokes or something? You are correct, but not quite in tune with the spirit of the post.

There is nothing funny about a minor slip that creates a discussion spanning over 400 comments.

gnomish
July 10, 2014 4:17 pm

never mind. bless your soul.
this has been illuminating, if not elegant. willis does it again!

bk51
July 10, 2014 4:18 pm

Wow, I can’t believe that such a simple mathematical expression has generated so much dialog.
First, I make no claim as to whether the identity expresses the true relationship between the volume of human-produced CO2 and the 4 terms on the RHS. I leave that to people more learned than me and my math degree.
Second, as instructive and entertaining as Willis’ posts always are, he got this one completely wrong.
As many have pointed out, what Willis did was verify that the unit of measure is the same on both sides of the identity. Peter Sable was the first to point this out, and also to say it’s a very useful technique in checking equations. As many have said, when you do dimensional analysis you better reduce down to 1 = 1 or you have a problem.
I didn’t bother counting how many people tried to put in numbers and ended up with CO2 = CO2. The biggest mistake I saw was substituting separately for the numerators and denominators of the terms.
For example, set population at 5 billion, then plug that into the first term (Population) and the second term (GDP / Population). Continue with other similar substitutions, divide like crazy, and you end up with CO2 = CO2. WTF?
But that’s not what the second term is. It’s a ratio – GDP per unit of population. It’s a single quantity expressed as dollars per person. The value of the denominator is held fixed at 1 – you don’t substitute anything for it! If there’s a change in population, you can plug that new value into the first term, and that might mean that there is a new value for the second term, but you don’t plug the new population into the denominator of the second term – it stays at 1!
The same holds true for the other 2 ratios. Energy used per single $ of GDP is expressed as Joules per dollar, and the denominator is 1 dollar. CO2 per unit of energy is expressed as (let’s say) tons per Joule. How many Joules? 1 Joule – that number doesn’t change in the ratio.
Those ratios are a bit esoteric, take one we are all familiar with – miles per hour. If my speed is 60 miles per hour, it means 60 miles in 1 hour. If my speed is 80 miles per hour, it means 80 miles in 1 hour. In any ratio of any type, the “per x” means per unit of x – the denominator is fixed at 1.
I really like steveta_uk’s M&M example – it’s very easy to visualize and understand. But even there, this identity, M = C * B/C * P/B * M/P, can cause confusion with people thinking each letter on the RHS is a quantity to be substituted for. Maybe it would be a bit clearer if we wrote it as M = C * (B/C) * (P/B) * (M/P) – there are 4 measurable values to be substituted for, not 7.
Finally, kudos to Nancy C for finally getting it, and seeing that LHS CO2 is not the same as RHS CO2. I’m not sure she gets the denominator bit like I describe above, but she has come a lot farther on the path to enlightenment than many others.

DanMet'al
July 10, 2014 4:21 pm

richardscourtney says: July 10, 2014 at 2:16 pm Well, perhaps you can tell us what use this ridiculous equation is except as a tool to spout political propaganda.
I, Dan, contend that you’ve lost your perspective. . . you don’t read or give thought to what others write. Here’s what I said earlier:
There appear to be two separate issues being argued in this comment thread:
(1) Some commenters believe that because the Kaya Identity can be reduced to the equation “Amount of CO2” = “Amount of CO2”, it has been falsified (unverified). From my view point, all identities share this property and if the two sides of an equation fail to have identical dimensions, that is a sign of a fatal problem. On this issue I side with Pete Brown’s comments on July 10, 2014 and later.
(2) The second objection(s) relate to George Box’s famous quote that “ all models are wrong; but some are useful. Clearly, the Kaya Identity is a simplistic “zero order model”; but apparently, Roger Pielke Jr. has found it useful for certain analyzes, I believe involving “what-if” analysis. And yet, given my own lack of exposure to Prof. Pielke’s work, it seems reasonable that more knowledgable people might find the application of the Kaya Identify to be problematic and subject to political chicanery. In others they find the model to have no practical value or utility.
So my conclusion is that while the Kaya Identity may be criticized as a non-useful or even an easily abused model, the identity itself can not be falsified on mathematical grounds based on Pete Brown’s arguments (relative to factoring) which I believe to be rational.
So I refute your assertion that I’m a troll. . . I try to think things out without demeaning others. Well you on the other hand. . . well I’ll let others decide. . . because I don’t care.
Thanks for your passion. . . guide it wisely!
Dan

gnomish
July 10, 2014 4:26 pm

i’m prolly gonna hate myself, but this is a nagging puzzle…lol
daniel says:
“M = C * B/C * P/B * M/P
M&Ms = Crates * Boxes / Crates * Packages / Boxes * M&Ms / Package”
daniel- let’s say we have 5 boxes. how many cases is that?
(answer: as many as you freakin want!)
not funny?

JJ
July 10, 2014 4:30 pm

Michael 2 says:
Really? A formula of the form X = A * (B/A) * (C/B) * (X/C) is not useful.

Yes it is. Apart from the obvious example of the Kaya equation itself – which whether you understand it or not is being used by people who do – there are many equations of similar construction that we use all the time.

You see, you must GUESS at the “X” for the forth term on the right hand side. Whatever you choose it will magically appear on the left hand side as though you have proved something.

The point of the identity is not the X. It is the relationship between A, B, C and X. More precisely, the point is the relationship between A, B/A, C/B, X/C and X. In the real world, those terms have meanings that are interesting to us.

No matter what you DECIDE is Global CO2 emission, the Kaya Identity will produce that EXACT value.

It also produces four other values – A, B/A, C/B, & X/C. And those values are of interest.

The complexity of it is a smokescreen and serves no purpose. Really! Give it a shot and see for yourself. Pick some random number for the numerator of the 4th term. Pick real or random numbers for everything else (but not zero). You will end up with the number you started with.
That is not how the identity is used. As an aside, why you are not just as fascinated by the fact that if you pick some value for the denominator of the fourth term then *POOF* it shows up as the numerator of the third term?

Now then, if you simply insert the laboratory measured value of co2 per unit of energy produced, THEN suddenly you have a meaningful formula.
Your argument thus becomes – The Kaya equation is useless because it is meaningless, until you use the useless Kaya equation, at which point the meaningless Kaya equation suddenly becomes meaningful. Brilliant.
Your goofy self-refutation example is sort of close to how the Kaya equation is used: By “picking” four of the five terms – X, A, B/A, C/B, & X/C – and observing what value the fifth must take. Or by “picking” some other subset of the five terms, and observing what the relationship between the remaining terms must be. But there is no “laboratory measured” value for the X/C term, or for any of the other four terms. They are all defined to be the exact values of the economy in question. That is the point of the equation, to provide an explicit symbolic rendering of the exact definition of the terms and their exact relationship to one another.

Our argument here is that the Kaya Identity is NOT USEFUL.

Your argument here is also that the Kaya Identity IS USEFUL.

An equation is designed to produce an answer on the left hand side based on stuff you know and can measure on the right hand side.

Uh, no. An equation is designed to make a relationship explicit in symbolic terms that can be manipulated mathematically. The notion that the “answer” is on the left is a third grade understanding of mathematics. With the Kaya equation, sometimes you solve for X. As commonly, you pick a value for X and see what you have to do to the other four terms to achieve that X. There is utility in that, and not just for warmists …

Daniel G.
July 10, 2014 4:33 pm

how many cases is that?

What do you mean by cases? (I don’t know)

Daniel G.
July 10, 2014 4:36 pm

But there is no “laboratory measured” value for the X/C term, or for any of the other four terms.

The point is that you don’t have to measure X directly.
But I think J.K showed how the identity is really useful. Future scenarios.

Will Nelson
July 10, 2014 5:08 pm

JK says:
July 10, 2014 at 3:59 pm
[…]
– We replace half of fossil fuel energy with nuclear energy, which as a first approximation emits no CO2.
[…]
CO2 changes by a factor of 1.1 x (1.3 / 1.1) x 0.9 x 0.5 = 0.585, so it falls by 42%.
******************************************************
Oops. In order for that last factor to be given as 0.5 then actually CO2 is 58.5% of initial since the other givens force the energy consumption to increase by 17% (58.5%/117%). So basically this exercise comes down to the given that CO2 decreased to 58.5% of the initial, to solve for final CO2 decreased to 58.5% of the initial.

Louis
July 10, 2014 5:13 pm

Joseph Murphy says:
July 10, 2014 at 11:57 am
Louis says:
July 10, 2014 at 11:49 am
M = P * M/P
This equation tells you how many total M&Ms there are if you know how many packets you have and how many M&Ms there are in a packet. Even though it reduces to M = M, the equation can still be useful if you want to know how many M&Ms you have without emptying out all the packets and counting each M&M individually. For example, if you have 10 packets of M&Ms and there are 100 M&Ms per packet, the formula tells you that you have 1000 M&Ms total (M = 10 * 100.) If you simplified the equation to M=M, it would still be valid, but it would become useless for making this calculation.
———-
Nah, you are using the total number of M&Ms to derive the per packet number. M&Ms per packet is a new variable and should be treated as such.
PP=M&Ms per packet
M=P*PP is what you want
PP=M/P is the other
You can’t use the same symbol for two different variables and expect no one to have a problem.
—–
Not so, Joseph. I did not use the total number of M&Ms to derive the per packet number. I didn’t know the total I had, so I used the number of packets and the M&Ms per packet to derive the total. Ten packets would amount to 1000. 25 packets would amount to 2500. No matter how many packets I have, I can use the formula to determine the total M&Ms (assuming the number per packet doesn’t vary).
M&Ms per packet (M/P) is NOT a new variable. It is a ratio using existing variables. Both M’s are the same variable, as are both P’s. Just plug the number of packets in for P and the total M&Ms back in for M on both sides of the equation and you’ll see that the equation holds up: 1000 = 10 * 1000/10. And also 2500 = 25 * 2500/25. The ratio (M/P) = 100 can be known without knowing either M or P separately (perhaps it’s on the packet label or you counted the contents of a packet before you decided how many packets to buy.) Once you know the number of M&M’s per packet (M/P) you can use P to calculate M, or M to calculate P using the formula M = P * M/P. But if you reduce the formula down to its simplest terms of M = M (or 1 = 1), it’s no longer useful for calculating anything.
The formula for calculating distance traveled is similar: d = t * d/t. Using miles and hours it becomes:
m = h * m/h.
If you know your speed (m/h or mph), you can calculate your miles traveled from the number of hours traveled, or hours traveled from the total miles traveled. If you have both the number of hours traveled and the total miles, you can then calculate the average speed in miles per hour (m/h). That is a useful formula. I have used it on occasion. But if you reduce it down to d=d, it is no longer useful. That’s all I’m saying. Just because you can reduce an identity down to it’s simplest terms doesn’t always mean that’s what you should do. Sometimes it’s the relationships of the variables that give a formula meaning.

Leon
July 10, 2014 5:37 pm

You wonder why Mann will not release his code.
Or Phil Jones: “WHY SHOULD I MAKE THE DATA AVAILABLE TO YOU, WHEN YOUR AIM IS TO TRY AND FIND SOMETHING WRONG WITH IT.”
Or U.S. Interior Secretary Jewell: “I hope there are no climate change deniers in the Department of Interior.” (They will let the American People know that the science is totally bogus.)
Or former Senator Timothy Wirth: “We’ve got to ride the global warming issue. Even if the theory of global warming is wrong.” (In other words, just screw it. We know it is wrong and we don’t care….It allows us to meet our political agenda.)

Will Nelson
July 10, 2014 5:52 pm

Louis says:
July 10, 2014 at 5:13 pm
[…]
m = h * m/h.
**********************************
This is a great equation if you know m ahead of time in order back calculate the ‘m/h’ rate, but you do need to know m first. Given m and h you can solve for m. The general and more useful equation is d = r * t.

Curt
July 10, 2014 6:16 pm

Will, you are missing the whole point. Would it be clearer if it were written as:
m = h * (m/h)
You get the (m/h) from your speedometer, let’s say 50 mph. At this speed, if you drive for 6 hours, you would go 300 miles. Let’s say you wanted to go farther. This equation tells you that you could do this by either increasing your speed, or driving for a longer time. The logic is equivalent to the Kaya identity.

Louis
July 10, 2014 6:16 pm

Will Nelson says:
July 10, 2014 at 5:52 pm
Louis says:
July 10, 2014 at 5:13 pm
[…]
m = h * m/h.
**********************************
This is a great equation if you know m ahead of time in order back calculate the ‘m/h’ rate, but you do need to know m first. Given m and h you can solve for m. The general and more useful equation is d = r * t.
_________
With d = r * t, if you know any two variables, you can calculate the third. But since the rate (r) is equal to d/t, you can also write the equation as d = d/t * t. Or, using miles for distance and hours for time, it becomes m = m/h * h, which is basically what I wrote above. You don’t have to know m first. You can know the rate (mph) without knowing the total miles traveled. So if you set your cruise control and keep track of the time, you can calculate the distance (m) that you travel from those values. There’s no need need to know m first.

Juice
July 10, 2014 6:29 pm

And wouldn’t you label it as EmissionsCO2 ?

Another Gareth
July 10, 2014 6:45 pm

From the bit that Willis quoted:
“CO2 emissions can be expressed as the product of four inputs: population, GDP [gross domestic production] per capita, energy use per unit of GDP, and CO2 emissions per unit of energy:”
Population multiplied by gdp per capita multipled by energy use per unit of GDP is a long winded way of describing total energy use. Multiply that by CO2 emissions per unit of energy and you have determined CO2 emissions. Which is what you already knew as part of CO2 emissions per unit of energy.
The Kaya Identity is useful for policy based evidence making. You decide what level of CO2 emissions you want and gauge how that might be achieved.
Daniel G. 7:53am said: “What happens to CO2 emissions in these scenarios (while keeping other variables constant):
1. increasing population? decreasing population?”
Nothing. CO2 is a variable like all the others. If you keep CO2 constant you keep CO2 constant. If you didn’t mean it quite like that then a change in ‘Population’ is canceled out by the corresponding inverse change in ‘GDP/Population’ and likewise for any variable you wish to change.
For points 2, 3 and 4 you are not changing a single variable but two and the net effect is the same – changes cancel out.
Daniel G 11:45am said: “Simple, all the ratios are more or less independent of each other. ”
The variables are. The ratios are not as they are expressed in variables that overlap. GDP per capita and energy use per unit of GDP necessarily use the same value for GDP. Energy use per unit of GDP and CO2 intensity of energy production necessarily use the same value for energy. If one ratio changes one or both of the other ratios change too depending on which variables have been altered, but the net effect is still no change.
Daniel G 12:11pm said: “No one is trying to discover co2 emissions, we have another measures for that.
But what would happen if for the generation of single unit of energy emitted 2x the Co2.
What would happen with energy-related co2 emissions? It would double too.
That is what the Kaya’s identity says.”
You do not need the Kaya identity to realise that energy related CO2 emissions doubling per unit doubles total energy related CO2 emissions. What the Kaya identity allows you to do is ask questions like ‘If the CO2 intensity of energy doubled, how big a hit might GDP and energy consumption need to take if we wanted to maintain a fixed level of total energy related CO2 emissions?’ However, I view those kinds of question to be a bit pointless and dangerous. Pointless because it supposes that global productivity and consumption can be tinkered with so directly. Dangerous because it becomes a self-fulfilling justification for politicians to try and grant themselves the authority to command global productivity and consumption.

Will Nelson
July 10, 2014 6:50 pm

Louis says:
July 10, 2014 at 6:16 pm
d = d/t * t
****************************
I’m not so sure. With this formula please solve for d without knowing d. lets say, t = 1 hr.
Curt says:
July 10, 2014 at 6:16 pm
********************************
Your speedometer does not read m/t (total miles traveled / total hours in trip…how could a speedometer know this?), it reads dm/dt.

Juice
July 10, 2014 7:04 pm

I’m sorry. I’ve read both sides of this and then read Pielke’s blog post about it and I still can’t see anything useful in this stupid identity. First, even if it outputs actual answers to inputs, which to me doesn’t look like it, it assumes that all the relationships are linear. Why would any of it be linear?

Will Nelson
July 10, 2014 7:07 pm

Curt says:
July 10, 2014 at 6:16 pm
*********************************
I think what we need to be careful of is not to change the meaning of the variables from one side of the eqn to the other. If m = total miles traveled on the left side then so it does on the right. Of course (total miles traveled) / (total time) can be used to calculate average rate. But it is necessary to know both those pieces of information ahead of time to solve your derivation.

Mike M
July 10, 2014 7:40 pm

Women = Time * Money and Time = Money so,
Women = Money^2
But of course, Money = (Root of Problems),
Squaring both sides, Money^2 = Problems
Therefore, Women = problems

Richarde Tete
July 10, 2014 7:47 pm

Wow, I never knew what a bunch of Phys.Ed teachers are posting here, and that is giving them a bad name. Good luck with your struggles. Hopefully there isn’t a math problem on the wet paper bags that are clouding your ability to see.
[this sort of condescending attitude towards others is exactly what is wrong with climate science -mod]

July 10, 2014 8:03 pm

[snip – don’t comment on personal things you know nothing about -mod]

1 16 17 18 19 20 28