Sea Coast of the Western Part of the Russian Arctic under Climate Change: Dynamics, Technogenic Influence and Potential Economic Damage

Round 1

Reviewer 1 Report

The paper is well organized and clear, and it makes an intelligent use of the scarce data available.

I have two comments to make for improvements. The first one is about the result of damage assessment. Of course the damage of areas where there are no human assets is lower. That is trivial. Nobody would have expected anything different. The authors present this is a main outcome but, as said, it only confirms the appropriateness of the approach and can be used to compare apple with apple and not with oranges. Hence I would like to have the authors discussing the potential damage of future economic developments. How much expected economic losses could be saved by strategically positioning shipping infrastructure in different under-developed areas? (this is just an example)

The second main comment is that the paper is lacking any sensitivity analysis. I believe this should be done in particular on the modeling of coastal dynamic and then assess how the impacts propagates through economic damage. In other words, the authors in section 3.2 in particular make several assumptions, mostly based on the constraints of lacking better empirical data. However, some of them should be analyzed. For instance, when an average value is chosen, the authors should study how the results would change by considering a median value or some other quartile. This will lead to obtain a sensitivity analysis, and I would concentrate on the assumptions on that section but, of course, for sake of completeness, the authors may want ot include also main assumptions in section 3.4.

In the second half of the manuscript in particular, there are sentences in which a few prepositions are missing, making it less readable. For instance, on line 425-426, the phrase "Even one climate scenario, the erosion rate can change several times in order to affect the area of the lost territory and, as a result, the range of potential economic risks." Makes no sense in English but probably would make it with "Even in one scenario".

There are several similar mistakes, please carefully edit the manuscript.

Author Response

We sincerely thank the respected reviewer for comments and remarks, valuable advice on improving the manuscript!

Reviewer 1.

Of course the damage of areas where there are no human assets is lower. That is trivial. Nobody would have expected anything different. The authors present this is a main outcome but, as said, it only confirms the appropriateness of the approach and can be used to compare apple with apple and not with oranges. Hence I would like to have the authors discussing the potential damage of future economic developments. How much expected economic losses could be saved by strategically positioning shipping infrastructure in different under-developed areas? (this is just an example).

Comment: The conclusion that “the damage is lower in places less man-developed” cannot be considered so trivial within the framework of the article, since the authors for the first time for Russia gave a quantitative estimate (in monetary terms). That is, the authors showed that not just “lower”, but “how much lower”. Moreover, for instance, the fact that all heavy objects fall to the ground has been obvious since ancient times, but it took a whole scientific theory to prove and justify this quantitatively.

This is a pioneer research for Russia, which was repeatedly emphasized in the manuscript. As such, it cannot claim to be comprehensive. For example, the authors in their previous works made forecasts of damage from continental permafrost thawing, first for the existing infrastructure, and in subsequent works for future investment projects. Previous experience thus showed that it is almost impossible to include both lines of research into one article due to their complexity and extensiveness. There is an objective limitation associated with the volume of the manuscript.

Necessary clarifications were included in the manuscript.

The second main comment is that the paper is lacking any sensitivity analysis. I believe this should be done in particular on the modeling of coastal dynamic and then assess how the impacts propagates through economic damage. In other words, the authors in section 3.2 in particular make several assumptions, mostly based on the constraints of lacking better empirical data. However, some of them should be analyzed. For instance, when an average value is chosen, the authors should study how the results would change by considering a median value or some other quartile. This will lead to obtain a sensitivity analysis, and I would concentrate on the assumptions on that section but, of course, for sake of completeness, the authors may want ot include also main assumptions in section 3.4.

Comment: We tried to consider median values and average values of coastal erosion for selected key areas, however, the considered ranges of retreat rates cover them as well. It is not possible to evaluate the sensitivity because it is pure mathematics. We looked at the most severe warm climate change scenario and current climate change trends over the past 40 years.    

Reviewer 2 Report

Dear author,

Thank you for the exciting and valuable article. Especially in climate change conditions.

I have a few comments, which are expressed below.

Figure 2 is originally compiled for this article, or it is cited from the previous works. It should be identified.

Line 150: .. punished data… What that means?

Line 154: it is unclear how was estimated coastal retreat rates. What key sites were used?

How was determined retreat value, in the table 1 and Figure 4? Where are these 4 spots located on the map (map are without the coordinate system)? If that was taken from other publications, couple of sentences with the reference on how it was done should be mentioned.

How is the thermo-denudation related to the occurrence marked on the Y axis at the figure 3? The figure should be clearer and how it was compound should be described in the materials and methods section.

Line 394: unclear how was obtained initial damage value? Please write more clearly.

Please add some comparison of similar works from the other places in the world. There is no discussion part in the result and discussion section.

Author Response

We sincerely thank the respected reviewer for comments and remarks, valuable advice on improving the manuscript! We tried to correct it in accordance with all comments:

Reviewer 2

Figure 2 is originally compiled for this article, or it is cited from the previous works. It should be identified.

Comment: The figure was obtained earlier and was presented in a paper [30]. In the previous article modeling due to thermal denudation was considered at various air temperatures which were observed in the past for the study region. The reference to paper [30] was added in the title of the figure

Line 150: .. punished data… What that means?

Comment: The typo “published data” has been corrected.

Line 154: it is unclear how was estimated coastal retreat rates. What key sites were used?

Comment: Coastal retreat rates were estimated by direct and remote methods. Chosen key sites were shown in Figure 1 (items 2 and 3).

How was determined retreat value, in the table 1 and Figure 4? Where are these 4 spots located on the map (map are without the coordinate system)? If that was taken from other publications, couple of sentences with the reference on how it was done should be mentioned.

Comment: Figure 4 is more general than Table 1. In order to more accurately determine the damage, some developed coastal areas were considered in more detail. Unfortunately, these local areas cannot be shown on the current scale of Figure 4, but they were taken into account when assessing damages (Table 1 is an example of such areas).

Coordinates have been added to Figure 4.

How is the thermo-denudation related to the occurrence marked on the Y axis at the figure 3? The figure should be clearer and how it was compound should be described in the materials and methods section.

Comment: Removed "thermo-denudation" from the title of Figure 3. The first version of the article was written about thermo-denudation due to the fact that the impact of climate changes on coastal erosion was estimated through an increase in air temperature, and the wind-wave effect was not used in any way due to its complex prediction.

How figure 3 was compound has been described in the materials and methods section.

Line 394: unclear how was obtained initial damage value? Please write more clearly.

The principle of initial damage value assessment described in “3.4            Assessment of the Damage Cost”. This paragraph has been added in response to this comment.

Please add some comparison of similar works from the other places in the world. There is no discussion part in the result and discussion section.

Since this work is the first for the Russian Arctic, the authors have placed a detailed review of similar studies in the "Introduction" section. In particular, cases of similar studies for the UK, USA are given.

Author Response File: Author Response.docx