The Evolutionary Trend and Impact of Global Plastic Waste Trade Network
Round 1
Reviewer 1 Report
The manuscript “Evolutionary Trend and The Impact of Global Plastic Waste Trade Network” addresses global changes in plastic waste trade. It provides an interesting analysis of trends across years, but is severely lacking a critical discussion that helps explain the observed trends. If this is accomplished, the manuscript will increase in value. Therefore, I recommend major revisions.
“Since 2020, there has been no plastic 79 waste import.” How could this relate with COVID-19 changes?
“The plastic waste trade directly 107 changes a country's plastic waste inventory, and then changes the distribution of marine 108 plastic waste[23].” Only during the short-term, since these plastics respect no boundaries and will move around the globe freely if given enough time.
Figure 1 – what is the source of this information?
“The export volume of plastic waste is much larger than the im- 120 port volume, and there is a large import gap, which has decreased sharply since 2016” What happened to this gap? Was it present in the market without being absorbed and sat on the original country waiting for export?
“The import ban on 133 waste plastics issued by China in 2018 has largely affected the global plastic waste trade.” Cheap plastic products were used to fuel China’s economic boom. Priorities now have changed, they have a big internal market and are shifting for more environmentally friendly practices. These motives could be discussed in more detail.
Figure 2 – Plastic waste – all are plastic waste, I believe this represents mixed plastic waste.
“the global plastic waste 150 import and export trade was dominated by polyethylene and polystyrene waste in the 151 early years.” These are also the most used by consumers, in pair with PP.
Recycled plastic has lower quality and it is hard to compete with the low price of virgin plastic. This analysis should take into account price fluctuations to identify motivators to accept or not plastic waste.
It is interesting that Hong Kong is both top importer and exporter of plastic wastes. This requires more attention.
“The 195 trade is mainly concentrated in Europe, Southeast Asia and North America.” How does this relate with waste management infrastructures?
“As the main export area, Asia is the import area, and Europe is gradually 198 the import and export area, and Asia is gradually reducing its import volume.” Some sentences are confusing, such as this one. English corrections are required.
Figure 6 – 13 should be combined as panels in a single figure. Also, these figures are too small, nodes cannot be read.
Figure 14 – I do not see any blue node.
A proper scientific discussion is missing here. So far, this is a report and not a scientific paper. A discussion of why and how this is happening is required. There are papers on regulations on plastics which can help interpret this. Other things that can be considered is the changes in plastic prices (also related with oil prices). Waste management systems in different countries can also be discussed. The study needs to be set on a global scale of the already published literature.
“The global plastic waste trade network has shifted its focus, and its import focus has 377 gradually shifted from China to Southeast Asia. After China promulgated the plastic ban, 378 the world’s major plastic waste exporting countries have seen a significant decline in ex- 379 ports, while Asian countries other than China and Japan have seen rapid increases.” This has been repeated since the introduction, but no “why” has been discussed.
What happens to this recycled plastic? Is it recycled or incinerated or just stored? How can they benefit or harm importing countries?
Why are countries more focused on internal market leading to a decline in trade of plastic? Are cost of exporting higher than creating national infrastructures?
Author Response
Dear reviewer,
Thank you very much for your suggestion! Your suggestions are very specific and useful, especially in the standardization of the format and the originality of the content.
Please kindly see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Dear Authors,
The paper "Evolutionary Trend and The Impact of Global Plastic Waste Trade Network" describes the global problem of the plastic waste amount, import and export directions. However, an improvement of the manuscript has to be performed:
- Line 107, the text should be supplemented with the information of accounting/amount calculation specifics regarding marine plastic waste and all plastic waste – are they counted together in the paper?;
- Line 402, an explanation should be given how COVID-19 acts on plastic waste amount trends;
- Graphical figures are missing both axis titles;
- Text writing errors need to be corrected (in many places ‘space’ is missing, punctuation is inappropriate, etc.);
- Numbers at the Y-axis of Figure 1 may better remain without additional zeros after comma;
- In lines 127-129, numbers are not of uniform format;
- In the titles of figures, the uniform description should be followed (mentioned unit in word or numbers, but no variation of both); I think you need to choose only one option mentioning numbers in tons or 10,000 tons all over the text;
- In several places (e.g., lines 100, 116, 127), numbers are divided from a word or unit; please use ctrl+shift+space in-between to avoid this mistake;
- English grammar errors should be corrected;
- Avoid referring to the first person in scientific writing (lines 306, 408);
- Decide which abbreviation you use all over the text – the U.S. or U.S.A. – but do not use both (lines 82, 221, Tables 4, 5);
- Combine Figures 6-13 into one or two big figures with subsections a, b, c…; font size in these figures is inappropriate (too small), I suggest to improve these figures by indicating the most important country points in a different colour;
- Regarding Chapter 5, it is better to start with a discussion and end with the conclusion;
- Lines 55, 65, 66 and 70 reveal not the uniform style of referencing in the text; please correct it - I advise the way as follows: Liang et al. (2021) discusses … [17].
- Also, the list of references has to be corrected, i.e., punctuation errors are present, as well as instead of ‘et al.’ all the authors have to be listed; if journal abbreviations and italics are used then for all journals;
- In appendix tables, it would be better to list the countries in alphabetical order;
- Figure 4 has to be combined in a better way (not losing some axis values);
- Reference to the data source (e.g., lines 137, 165) should be listed in the list of references and mentioned by number [xx] in the text and figure titles.
Comments for author File: Comments.pdf
Author Response
Dear reviewer,
Thank you very much for your suggestion！Your suggestions are very specific and useful, especially in the standardization of the format and the originality of the content.
Please kindly see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 1 Report
The authors have put a lot of effort on the corrections of this manuscript. I have found some sentences needing restructure, which I have suggested below. Also, there is one or two points that can be better addressed to increase the value of the manuscript. After these minor corrections, the manuscript can be accepted.
L81-82 “In order to prevent the infection of the virus, more consumers will use disposable products.” Change to “In hopes of preventing infection, more consumers used disposable products.”
“The COVID-19 epidemic has changed consumer habits. Millions of plastic cups, protective clothing, syringes have been used.” Here it could be said that packaged food and takeaway packaging increased, in addition to medical waste. In the case of PPE used by the public, it strains municipal solid waste. But PPE and syringes used in healthcare are treated in another stream of waste (usually incinerated).
L201-203 “, countries are seeking new solutions, to expand domestic market or promote plastic recycled plastics processing technology, a redesign of plastic packaging for recycling” remove first plastics in recycled plastics.
L225 “and can be found in the 1990 s China recycle plastic waste profitable,” to “as can be found in the 1990s when China recycled plastic waste profitably by using it in the manufacturing industry. China’s (…)”
“China's demand for plastic is driving the global plastic trade, China to accept more than 50% of the plastic, this makes China at the beginning of the 21st century the world's factory.” To “(…) leading the country to accept (…) making it the world’s factory at the beginning of the 21st century.”
“Polyethylene and polystyrene mixed with polypropylene are the most commonly used products by consumers” can be referenced to https://www.plasticseurope.org/en/resources/publications/4312-plastics-facts-2020
Figure 2. This is figure is great! I would add a line on the price of virgin plastic for comparison. Optionally a secondary axis regarding the volume of traded plastic waste could be added to compare trade with prices.
“The price of each unit fluctuates greatly, with high price in 2009, 2012 and 2014, and low price of import and export per unit in recent years.” Why in these years? What drives prices up should be discussed.
Author Response
Dear reviewer：
Thank you so much for spending your valuable time again to provide us the detailed and constructive comments. Much appreciated! We have carefully followed your instructions and made the changes. In addition to the minor language issues, we have taken this opportunity to apply professional proofreading service to review the whole text.Please see the attachment.
Author Response File: Author Response.pdf
