A Tax Coming from the IPCC Carbon Prices Cannot Change Consumption: Evidence from an Experiment
Round 1
Reviewer 1 Report
This study presents the same results as the general prediction through experimental analysis of consumers' choice of milk consumption considering GHG. I personally read this article interestingly because I have an interest in the subject of this study.
However, even in the case of experimental research, it is necessary to fully examine the theoretical background in order to increase the academic contribution.
It is composed of introduction to Line 27-129, but it is necessary to construct the theoretical background separately from this chapter. I recommend that the chapter include consumer behavior in environmental issues, tax issues in eco-friendliness, and tax correction effects.
In particular, in terms of research methodology, WTP usually measures with contingent valuation, and you will be able to develop a systematic thesis by presenting theories and literature on it, and by distinguishing it from the methodology you used.
Author Response
Dear reviewer 1,
Thank you for your review.
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Thank you for the opportunity to review this manuscript. It offers a timely and policy-relevant analysis based on a behavioral and experimental methodology, assessing the carbon price equivalence of differences in consumer valuation of environmental and health impacts of different types of milk - expressed in consumer willingness-to-pay - resulting from improved information on such environmental and health impacts. It also uses an intriguing approachby using WTP data derived from an experimental setting as a proxy for perfect information, and wisely acknowledges information asymmetries and bounded rationality in real-world settings to consider how perfect information could be substituted with taxes/subsidies based on the experimental survey results. Also welcome is that the authors consider multiple externalities (climate impact; pesticide/fertilizer burden; health; animal welfare).
While this reviewer's expertise is purely qualitative, and thus does not allow to comment authoritatively on the experimental methodology and quantitative evaluation of results, the approach chosen in the manuscript is clearly described and seems robust. The conclusions - including that more research is needed on consumer valuation of different types of environmental damage, and on the implications for a welfare-optimal Pigovian taxation regime - appear compelling, and supported by the analysis.
Some comments and minor suggested improvements follow:
p. 5: Generally good framing of the messaging "treatment" of study participants; possibly somewhat too abstract messaging on the link between cows and climate impacts for the message on GHGs (how relevant are 92% of land use emissions relative to emissions from all sources in France and/or globally? What are climate impacts expected from current emission levels?); and somewhat suggestive/morally charged language in one of the questions (message about animal welfare: "exploitation of animals"), but these should not meaningfully diminish the value of the study, and certainly of its broader implications.
p. 13, l. 368: assuming an identical carbon footprint for organic and regular cow's milk may ignore life-cycle emissions from differences in the feed used, and agricultural practices related to feed: organically raised dairy cows are more likely to be pastured, in which case they produce less methane, and some emissions from e.g. growing corn and other cereal inputs (as opposed to local pasture), plus transporting and processing these, can be avoided; even with identical feed, organically grown products are generally less carbon-intensive (e.g. fertilizer/pesticide-related emissions; different soil management practices & impacts). I unfortunately cannot point to relevant sources and data (esp. since standards and practices vary across countries and regions), but it would offer an additional, interesting nuance to the analysis and results if climate impacts of organic vs. conventional practices are reflected.
On a more general level: what are the implications of a product-differentiated carbon price (as proposed by the authors, e.g. in the conclusions on p. 17) for the efficiency of a carbon tax as a policy instrument (that levels marginal abatement cost across all abatement options in equilibrium to achieve Pareto-optimality?) Tihs may also play into the discussion of the potentially different outcome when more than one product category is included in a bundled WTP-justified carbon tax, e.g. on all types off foods, or indeed on all product-related emissions.
Some typographical and grammar errors remain in the manuscript, and need to be addressed in the final version (e.g. l. 44: "WTP are" should be "WTP is" - also, please spell out this acronym in the manuscript body, even if it was spelled out previously in the abstract; l. 47: "and the half of it" should read "and half of it"; l. 64: "impact of IPCC carbon price" should read "impact of the IPCC carbon price"; p. 16, l. 478: "consumers are
would accept a tax" presumably should read "consumers are willing to accept a tax."; p. 17, l. 516: "by the IPCC, for." should presumably read "by the IPCC.")
Likewise, some further streamlining and corrections are needed in the tables and figures, e.g. on p. 4, Table 2, the code for Organic Cow Milk is indicated as "OSM" (should be "OCM"); on p. 7, Figure 1, the legend of the figures lists RCM and RSM as NOCM and NOSM, which is inconsistent with the abbreviations used in the text and previous tables.
Author Response
Dear reviewer 2,
Thank you for your review.
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Dear Authors,
I believe you have touched an interesting issue by focusing empirically on the topic of taxation, environmental policies and consumption preferences. Taxation within the framework of environmental challenges is a hot topic nowadays, especially taking into account the increasing climate risk worldwide countries are facing. The results and policy implications you have drawn are important for the success of similar future endeavors targeted by decision-makers. Such topics certainly need to be investigated and examined further to expand scientific as well as practical knowledge. Therefore, I believe the present study is valuable for the scientific community and practitioners alike. The manuscript would benefit from few modifications, so please find some general and detailed comments regarding these modifications below.
General comments:
For consistency reasons, when enumerating three of more elements, either put a comma after “and” (as in American English) or leave the comma. Sometimes you add it, sometimes you do not. See, for instance page 3 line 117 and page 3 line 120.
Sometimes you display the symbol “e” in front of numbers, sometimes after the number (see, page 12, line 390). Moreover, I suggest you replaced this “e” with the standard symbol for Euro (€). For many readers, “e” doesn’t mean anything.
In the reference list, please remove the black spaces between the page numbers and the hyphen. In some cases there is no space, but in most cases the spaces appear. Moreover, I suggest to uniformly format the title of the sources: either all words in lower case or all words with the first letter in uppercase, but not mixed.
You use currency abbreviation for the dollar (USD) but not for the euro. For consistency reasons, please report currencies in a similar manner.
Detailed comments:
Page 1, line 31: “International Panel for Climate Change (IPCC), for limiting greenhouse…”. Please delete the comma in this section.
Page 2, line 47: “…the half of it”. Please delete the article before “half”.
Page 2, line 63: The correct wording is “in terms of”.
Page 2, lines 87: …”suggests a per-ton carbon price between e 40 and e 80 in 2020, e 50 to e 100 in 2030, and e 125 to e 140…”. What does “e” stand for? Euros? Please explain.
Page 3, lines 111-112: “….(see Borger & Glazer (2017), Gahvari (2014), McAusland &….”. I suggest deleting the parentheses in which the year of publication was written. This should be written as: “(see Borger & Glazer, 2017, Gahvari, 2014…”.
Page 3, lines 112-113: “The methodology….are overlooked”. Please change the verb “are” into “is”, to be in accordance with the subject of the sentence.
Page 3, line 117. Insert a blank space before “Bai et al.”, after the comma. It appears to be missing.
Page 3, line 126: “did not study the market adjustments regarding final products”. Please delete the article “the” from the sentence.
Page 3, line 125-126: “…the CPLC (2017) who did not study….”. I suggest replacing “who” with “that”.
“Who” is used for human beings and I presume this is an organization.
Page 3, line 134: The correct spelling is “performance-based financial incentives”. Please separate the two words.
Page 4: Please format sections “Income” and “Academic” in Table 1. The current display is not very straightforward, it is confusing. I suggest putting each information on a different row, like you did with “Sex”. Below the table, I suggest writing “Note:” right before the explanations regarding the questions.
Page 4, Table 2: The second code from the left should be “OCM”, not OSM. Again, is the price in “Euros”? If yes, you should either write that or put the symbol.
Page 6, Table 3. The initials for each message from Table 3 (e.g., PES, GHC) should be included on the previous page, where you list all messages. This way, readers will identify exactly the message to which you are referring.
Page 6, line 213: “…on the Y-axis, starting at e 0.40, to e 1.20. Each…”. I suggest using either the symbol € or writing “euros”.
Page 7, figure 1: Please explain what “NOCS” and “NOSM” mean.
Page 9, line 275. Please insert a blank space before the mathematical formula.
Page 9: try to rewrite the mathematical formulas with Equation editor. Currently, there are big differences between some formulas displayed on this page and other formulas.
Page 10-11, figures 2-3: I suggest writing the explanations below the graphs using a smaller font. It is contrasting when compared to the caption of the figure, which is quite smaller.
Page 13, line 385: “These results are presented as variations form the baseline scenario”. The correct wording is “from the baseline scenario”.
Page 13, table 5: The explanations in the note are unclear. Do you mean that in parentheses you show the number of units purchased under perfect information? Also, the abbreviation for number is “no.” not “nb”.
Page 14, line 403: “The three last columns…”. The correct wording is “the last three columns”.
Page 14, line 410: “imposed on both RCM RSM because of the…”. Please insert a comma before RCM and RSM.
Page 16, line 478-479: “…we cannot say that consumers are would accept a tax”. Please delete “are”, there is already a verb in this sentence.
Page 17, table 10: Please reformat table 10, because its content cannot be understood. Moreover, several words are bound to each other.
Page 17, line 516: “on the carbon prices proposed by the IPCC, for.” Please delete the word “for” after IPCC.
Pages 18-19: Would it be possible to rewrite the mathematical formulas so that variables are displayed on the same row, from one end to the other? Currently, there is no uniformity in their display. Also, please use the Equation editor for writing them. There are special functions in displaying a variables that goes from i=1 to N.
Page 19, lines 596-597: “…on consumers’ willingnessto-pay for…”. Please separate the two words in “willingness” and “to”. Also, spell China with capital C.
Page 20, lines 608 and 633: Please insert a comma before 2019, as in “July 1st, 2019”.
Page 20, line 622: Please remove the spaces after the publication year.
Page 21, line 636: “…Do you not like pigou, …”. I think it should be Pigou, with uppercase.
Page 21, line 640. Please try to write the name of the paper immediately after the publication year. At the moment, there is a blank space between these elements.
Author Response
Dear reviewer 3,
Thank you for your review.
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors revised the paper to reflect my first review. However, it is better to pay more attention to the summary of the research results in the abstract and conclusion section.