Talk:Economics of global warming

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Kaya identity[edit]

I see some issues with the Kaya identity. I tried accessing the original book, but was unable to, so I hope someone with access to the book can contribute.


  • why is the identity split out on two lines? (I tried to fix it and failed)
  • While I appreciate that it is an identity, which explains why the identity symbol is used, I have seen the identity included in several sources with an equals symbol. Don't we need at least one reference using the identity symbol to avoid OR?
  • The article Kaya identity expresses the identity using LaTeX and a different set of symbols. Unless someone articulates a good reason for a different presentation, the presentation should be the same.


  • This identity has four factors, but the identity in the IPCC has three. Which is the preferred version?
  • The IPCC identity refers to GHG, while this page uses CO
    . I understand that CO
    is sometimes used as a placeholder for GHG, but that doesn't mean we can be so cavalier. My guess is that the original talks about GHG or emissions, not CO
    --SPhilbrick(Talk) 16:38, 23 April 2012 (UTC)
I have had no difficulty accessing the cited sources [1][2][dead link]. The publications are also available commercially [3][4]
These issues are explained in the cited sources. The use of the Kaya identity in this article exactly follows its use in the cited source (Stern, 2006). I checked Kaya identity. Indeed, it presents the identity using LaTeX, but its content is the same as here, apart from the use of an equals sign instead of an equivalent sign. The cited source uses an equivalent sign. I don't see this as a major issue, either sign appears acceptable.
You are incorrect about the cited source referring to GHGs (presumably individually or aggregated to CO2-eq) rather than to CO2 only. There is nothing "cavalier" about using the Kaya identity to express changes in CO2 rather than CO2-eq. The two uses (three components or four) depends on what analysis is being presented. Decomposing into four components allows carbon intensity per unit of energy use to be distinguished from energy intensity of GDP. This is entirely consistent with the use of the Kaya identity in the IPCC report [5]. Enescot (talk) 06:06, 11 September 2012 (UTC)
I quote from IPCC
The reason can be illustrated by using the Kaya identity, which decomposes the emissions as follows:
GHG = Population x GDP per person x Emissions per GDP
or: (graphic not reproduced)
where GHG stands for greenhouse gas emissions, GDP stands for economic output, and POP stands for population size.
Why do you claim it doesn't use GHG?--SPhilbrick(Talk) 16:09, 3 October 2013 (UTC)
I did not claim that the IPCC report only refers to the 4-component, CO2-only Kaya identity. The IPCC report refers both to the identity that is cited in the article and the identity which you have cited – see the link that I cited previously, or page 66 (PDF numbering) of this report. Enescot (talk) 08:38, 4 October 2013 (UTC)

Potential resource[edit]

Thanksgiving News Flash: Things Are Getting Better! by John Horgan Scientific American November 22, 2011 (talk) 06:29, 4 January 2012 (UTC)

Interesting article, but I missed the relevance to this article. I didn't see an reference to global warming. Did I miss it?--SPhilbrick(Talk) 13:30, 25 April 2012 (UTC)

Potential resource[edit]

Good article and relevant. However, at present, the article is in poor shape, and I see many pressing issues that should be addressed first. If some of the economic gibberish is improved, it might then be appropriate to see if this link can be incorporated.--SPhilbrick(Talk) 13:38, 25 April 2012 (UTC)

Cost-benefit analysis[edit]

The section claims that the monetary metric is willingness to pay, as opposed to net present monetary values. The two are not, in general, close to each other. The notion of using "willingness to pay" is an interesting concept, but it is not the canonical use (if Cost–benefit analysis is accurate), so some justification, and a reference is needed. If one is found, then the claim that it is "standard" should be changed. More likely, it is simply a mistake to claim that the CBA should be using "willingness to pay".--SPhilbrick(Talk) 15:08, 5 May 2012 (UTC)

Seeing no objection, I will change the metric to the more usual net present value.--SPhilbrick(Talk) 00:40, 18 June 2012 (UTC)
It is not a mistake - I've added the appropriate references to a reliable source, and revised the section.
I'm not sure what your argument is. In CBA where WTP is used, usually everything is still aggregated into a monetary value, with risk accounted for using certainty equivalents, which is then discounted to produce present values.
You state that "The section claims that the monetary metric is willingness to pay, as opposed to net present monetary values. The two are not, in general, close to each other." What are you comparing WTP-derived valuations with? Enescot (talk) 05:57, 11 September 2012 (UTC)

Spacing with degree symbol[edit]

I removed the spaces (normal and nbsp) before the degree symbol. This is normal American usage for both scientific and non-scientific texts, recommended by the University of Chicago Press and Oxford University Press. And I thought it was required by this, from the MOS: "The percent sign, and units of degrees, minutes, and seconds for angles and coordinates, are unspaced." However, I then came across this discussion from 2005 (, which points out that several scientific style guides require a space before the symbol. Looking at the MOS, the prescription is not as unambiguous as I thought. It might be interpreted as being about coordinates and saying nothing about temperatures. So it seems that this question has still not been settled. If someone wants to revert my edit and restore the spaces I won't object, even though I still think it will look odd to 99% of American readers. It would be helpful if the MOS could come up with a more explicit rule for temperatures. Margin1522 (talk) 11:24, 22 August 2012 (UTC)

OK, sorry, looks like I didn't read far enough. The MOS does recommend "but 18 °C for a temperature". So I am going to revert my own edit and restore the spaces. I still think it looks odd. Any comments? Margin1522 (talk) 11:39, 22 August 2012 (UTC)
Beat you to it :) Doesn't look odd to me. Vsmith (talk) 11:48, 22 August 2012 (UTC)

Citation style[edit]

As detailed in the Citation style tag, there should be a consistent style. There doesn't seem to be a predominant style, so I'm starting the discussion on what style to use. –Temporal User (Talk) 08:11, 3 May 2013 (UTC)

Over the last year, I have been gradually revising the citations in this article. I think the harvnb template works well, e.g., see effects of global warming. I find revising citations very tedious, so I've broken up the workload. Enescot (talk) 07:27, 19 May 2013 (UTC)

Impacts section[edit]

I'm thinking of revising economics of global warming#Impacts. In my opinion, the main problem with this section is that it does not discuss non-monetized impacts. A risk-based approach would account for the full range of climate change impacts. This is relevant to the article, since a broad understanding of climate change impacts is necessary when making policy decisions. There's already an article on the effects of global warming, so it's probably only necessary to present a brief summary of the most important risks and benefits of climate change.

The section's coverage of monetized impacts should be revised in view of more recent studies.


Enescot (talk) 08:23, 5 August 2014 (UTC)