A note: Of course the small scale things are the right thing to do. Switching streetlamps to LEDs alone will save immeasurable amounts of energy. I’m just saying that focusing on shutting things down is not a good way to go about this. We should focus on improving in ways that are more ecologically friendly, while at the same time cheaper and faster.
As kimstu notes, this equation is contained in the supplementary materials where, for completeness, they give a brief overview of the entire DICE model. However, since they don’t directly consider damages due to climate change in this paper, I don’t actually see where that aspect of the DICE model is even relevant to their calculation. Feel free to point out where you think it comes into play if you think otherwise.
As I noted in my first post on this, the most interesting thing about their paper (in my view) is that they start from a very minimalistic set of assumptions: namely that there is the climate sensitivity parameter whose value we don’t know today but will in 2035 and that there is some temperature change from the present above which damages due to climate change become so large that we don’t want to exceed this temperature change, again a value that we do not know today but will in 2035. The general conclusion is that quite generally, over a broad range of realistic possible values for both the climate sensitivity parameter and the maximal acceptable temperature change, it is cheaper to start “buying insurance” by putting a cost on carbon emissions today than it is to wait until 2035 and then to take the necessary actions to stay below the maximum acceptable temperature change. (In addition, waiting may make some realistic maximum acceptable temperature changes essentially unachievable, depending on what the climate sensitivity turns out to be.)
Hence, they basically finesse the issue of damages due to climate change. They just assume that there is some temperature at which the damages become unacceptably high and then ask what is the most cost-effective way to make sure we don’t exceed that temperature given the uncertainty that exists today in our knowledge of what that temperature is and what the climate sensitivity is.
Kimstu, I appreciate your response. My apologies for not specifying that the equation was from the SOM, I thought it would be obvious given the short length and the absence of equations in the study.
Contrary to your assumption, I had looked very closely at the work cited (Nordhaus and Boyer). You should know by now that I do my homework. They do not give the values for those variables either. They only say (p 4-7)
Note that they do not provide a physical basis for the setting of these parameters, only that they are set so that the optimal carbon tax matches a previous model.
A description by Nordhaus of a later run of the model (2006) gives the parameters as theta1 = -0.0045, theta2 = +.0035. In addition, these same values are used in the Excel version of the DICE-99 spreadsheet from Nordhaus’s home page. However, since one of these is negative, these cannot be the parameters used in the “Hedging” study.
Thus, as I said, the authors have used their own parameters (which give larger damage estimates), but have not specified them …
w.
PS - There is an interesting analysis of some of the dangers and shortcomings of this kind of coupled climate/economic modeling available here.
jshore, I must confess I don’t understand this post. The analysis is only valid if a) the climate model is correct, and b) the economic model is correct. They have not shown either one of these assumptions is true.
To say that they can “finesse” these fundamental issues glosses over a whole host of unverified assumptions. See the note at the end of my response to Kimstu above which contains a link explaining some of these issues in greater detail.
w.
Well, since the authors of the “Hedging” paper haven’t seen fit to tell us what their values for their economic damage coefficients are, I’ve had to look at the original coefficients in the DICE-99 model referred to in their paper. They calculate the damage from increasing temperature, using the 1900 temperature as their zero point.
Using the DICE-99 coefficients, here are their estimated climate damages for various amounts of temperature rise since 1900. Negative values indicate a benefit, and positive amounts indicate a damage. The damages are in percent loss of Gross World Product.
Temperature Rise (degrees) Damages (% of GWP)
0.0 0.000
0.2 -0.076
0.4 -0.124
0.6 -0.144
0.8 -0.136
1.0 -0.100
1.5 0.113
2.0 0.500
2.5 1.063
3.0 1.800
3.5 2.713
What this means is that the authors claim that starting in 1900, rising temperatures were a net benefit. No net damage from increasing temperatures, but net benefits instead. Who would have guessed?
This benefit increased until the temperature rose 0.6°C above the 1900 value, which is … oh, my gosh, that’s right about now. What an unbelievable coincidence! We exist at the exact ideal temperature, where we get the maximum temperature benefit. Pangloss was right, “All is for the best in this best of all possible worlds.”
Unfortunately, not all the news is good. In a tragic twist of fate, from now onwards, rising temperature is no longer a benefit as it was in the past, but becomes a rapidly increasing damage …
Like I said, folks, when you can play with the assumptions, you can “prove” anything. My advice? Don’t believe anything until you look under the hood and examine the machinery. Peer review means nothing.
w.
intention: Sorry I have been slow to get back to you on this. Let me explain to you what I was originally thinking: I thought that since the “adjustment costs” for the two cases was for getting to the same final temperature but by different routes (mitigation starting today vs. no mitigation until 2035), the damages in the two cases would be the same and thus we were only looking at other economics costs.
Now, however, I realize that this is not quite correct because the two different routes will have different values of the temperature T(t) along the way. So, presumably the two different routes do have somewhat different amounts of damages due to climate change. I guess the question would be whether this is a major component of the different “adjustment costs” between the two cases. I don’t know the answer to this…although it might be in the Supplementary Materials if we read through them more closely, which I will try to do when I get the chance.
A few years ago, long before the current mass hysteria about lightbulbs and CO2 emissions I pondered what other device in the home hadn’t changed, literally in a hundred years. I really couldn’t think of any. But the good ole’ lightbulb - 90 percent heat or something. Without it though - the vacuum tube could not have been discovered, eventually resulting in compact, multi-section tubes - then nuvistors, transistors and eventually ICs, and the rest is, as they say history.
The C. Crane Company had, and still has, a bunch of really cool LED products, flashlights and that sort. I figured this was a great investment opportunity because the current demands are so much less, coupled with longetivity. But I found that all the companies are in China, and it’s doubtful of any LED or LCD manufacturing in the U.S., probably because of pollution concerns it’s fairly gnarly.
Still it seems to make sense to go towards the use of LEDs versus flourescents.
jshore, thanks, I figured you were otherwise occupied.
My point is that their analysis is critically dependent on the estimate of the damages, as well as on the efficacy of say a 3¢ per gallon price rise on cutting gasoline. Their estimate of the damages, as I showed above, is … well, let me call it “interesting” and let it go at that. In addition, they do not show that a 3¢ gasoline tax will have any effect at all.
Finally, they have some curious assumptions about the increase in CO2 emissions (as given in their spreadsheet). For example, they are using 4.1 W/m2 forcing change per CO2 doubling, whereas everyone I know uses 3.7 … of course, this increases the projected temperature for a given doubling.
They also somehow end up with much more carbon in the atmosphere for a given emission rate than that calculated using the standard model (the Bern Carbon model.) This also increases the projected temperature.
Because of all of these problems, unrevealed parameters, difficulties, exaggerations, and curiosities, I would not put any credence in their results. You’re welcome to believe them if you want, of course … but I’ll pass, thanks.
w.