Comments 1 to 6:

1. Dawei at 08:40 AM on 28 October, 2019

   The abstract of "Are global tropical cyclones moving slower in a warming climate?" concludes that AGW is likely *not* having an effect on cyclone speed. (Betteridge's law should have been a clue). 

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2. One Planet Only Forever at 11:34 AM on 28 October, 2019

   Not far below the abstract the following is stated. Note the use of "may" regarding claims that are implied to support the suggestions of this paper.

   "Recently, Kossin (2018a) reported that the global tropical-cyclone translation speed over the 68 year period 1949–2016 was slowing down by 10% and implicitly related this to the weakening of the tropical circulation forced by the anthropogenic warming (Held and Soden 2006, Vecchi et al 2006, Vecchi and Soden 2007, Coumou et al 2015, He and Soden 2015, Grise and Polvani 2017, Mann et al 2017). He thereby suggested that it might result in more local rainfall totals in the warming climate, particularly over land. Such findings and implications have been widely interpreted, broadcasted and forwarded by various social media and sectors since then (Guglielmi 2018, Patricola 2018, Shultz et al 2018). Unfortunately, his study was imprecise and questioned. The early work of the present study pointed out two deficits in his calculation of tropical-cyclone translation speed and an author correction had been made after (Kossin 2018b). Although the correction shows no material impact on the key conclusions of the original study on a global scale, it has a number of varying effects on regional scales. Such varying effects are more apparent for tropical cyclones over land. On top of that, this study further suggests that the slowdown of global tropical-cyclone translation speed stated by Kossin (2018a) may not be a real climate signal or it may be exaggerated, which is consistent with what Moon et al (2019) and Lanzante (2019) commented coincidentally."

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3. Dawei at 13:37 PM on 28 October, 2019

   One Planet, I'm not sure what point you are trying to make. The paper is clearly intended as a counter to the claims of cyclone slowing. The authors argue there's no evidence for it, so this paper shouldn't be listed in a group called "Observation of global warming and global warming effects" (its whole purpose is to argue that the case for this being one of its effects is weak to non-existent).

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4. Doug Bostrom at 15:21 PM on 28 October, 2019

   In the abstract of the paper Dawei mentions, we read  this:

   A recent astounding study reported a 10% slowdown in global tropical-cyclone translation speed over the past 68 years (1949–2016) and implicitly related this to the weakening of tropical circulation forced by the anthropogenic warming. It thereby suggested that it might result in more local rainfall totals in a warming climate. However, here this study shows that no robust and significant observational and modeling evidences reveal that they are.

   The paper goes on to discuss the author Chan's reasons for disagreement with the paper he cites. Both papers are discussing effects of global warming,  Chan in a slightly more histrionic but otherwise standard format. Finding a negative result does not vanish the topic, so to speak. 

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5. One Planet Only Forever at 01:52 AM on 29 October, 2019

   Dawei@3,

   Doug has provided a good reponse regarding the section the Report is listed under.

   I will provide the following in an effort to respond to the other parts of your comment.

   The abstract ends with the following: "The relationship between the slowdown of tropical cyclones and anthropogenic warming is therefore not apparent and the relevant potential increase in local rainfall totals in the future warming climate is suspicious."

   That appears to be inconsistent with claiming "...that AGW is likely *not* having an effect on cyclone speed".

   My comment was pointing out that, in addition to reading the complete abstarct, reading just a little further raises even more doubts about the claim "...that AGW is likely *not* having an effect on cyclone speed".

   Along the lines of Doug's point regarding the category for the Report, claiming to doubt a conclusion of another report that has already been corrected without the corrections affecting the conclusions seems to indicate that serious skepticism should be applied regarding the claims this report appears to try to make. The author is not refuting the revised conclusion of the other report. They appear to be trying to tell a different story based on their personal interpretations of selective information.

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6. One Planet Only Forever at 00:01 AM on 30 October, 2019

   Dawei@3,

   The following points may clarify my thoughts regarding "Are global tropical cyclones moving slower in a warming climate?", specific regarding it suporting a claim "...that AGW is likely *not* having an effect on cyclone speed":

   • This document attempts to be a follow-up to a previous attempt to refute an evaluation of the full global satellite data set that strives to establish if, with the limited data currently gathered, there is evidence that the rate of movement of cyclones is reducing (they are moving slower), with the related result that the total amount of rain and wind damage from a cyclone event on a location could increase. The most likely cause of such a change of behaviour would be global warming.
   • The previous critique of that report by this author resulted in modifications of the original report that did not change the conclusion of the report.
   • This new critique appears to attempt a more detailed evaluation of regional 'sub-sets of the accumulated global satellite data'. If the global total data set is only marginally large enough to identify trends in, no sub-set should be expected to be large enough to note a trend. Yet the author seems to want to claim that their identification of 'regional speeding-up of movement after the eye makes landfall (my para-phrasing)' can be identified and is the basis for refuting the global evaluation.
   • A lot of rain and wind damage can occur before the eye makes landfall. A recent major damaging storm swept up the coast of Florida without making landfall. And many others have done that. However, Dorian definitely 'sat on top of land for a long time', unlike cyclone movement after the eye finally makes landfall on a large land mass (the type of regional difference that the author seems to want to focus on - and it is possible that Dorian's behaviour above an 'island' would be excluded from the 'regional behaviour after landfall' that the author appears to want to write a story about).
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