Do Not Cite, Quote, or Distribute IPCC SREX Chapter 3, FIRST-ORDER DRAFT From From To To # Ch Comment Response Page Line Page Line 1 3 0 0 0 0 Congratulations! Already in its present draft this chapter is mature, comprehensive and well elaborated; a great achievement Thanks. Have provided Chapter 3 ES to other chapter CLAs to ensure which has been accomplished in a relatively short period of time. My comments below are generally minor. In addition to consistency. further shaping the text of this chapter, I think it will be important for the authors to review the other chapters and ensure that their assessment (as documented in Chapter 3) is consistently followed in the other chapters of the report! (Klein Tank, Albert, KNMI) 2 3 0 0 0 0 Some further structuring of the text is recommended, in order to avoid redundancy and in order to shorten the number of Noted. Have worked to remove duplication for SOD. Recruited CAs to pages. I must admit that I had some difficulty reading until the very end. This is partly due to the fact that I am not an expert improve geographical coverage. on areas such as waves, coastal impacts, glaciers, etc. Also, I suggest placing the details and examples further apart from the main messages and conclusions where possible. At present, a significant fraction of the literature is mentioned several times. This is due to the fact that each section is broken down into the three parts: observed changes, causes and projected changes. Most of the examples are from either Europe or Australia. Given the sparse information from other regions of the world (with the exception of North America), it may be difficult to avoid this regional bias. (Klein Tank, Albert, KNMI) 3 3 0 0 0 0 NOTE: I am a contributor of Chapter 3, so I do not review this chapter (Cavazos, Tereza, CICESE) Noted. 5 3 0 0 0 0 No comment (Jegillos, Sanny, UNDP) Noted. 6 3 0 0 0 0 The wording has to be consistent within the whole manuscript: e.g., the expressions "return period" and "return times" are Agreed. Have worked to ensure consistency in these terms. Have also different expressions for the same issue (Kunz, Michael, Karlsruhe Institute of Technology (KIT)) noted in the SREX glossary that the term "waiting time" is equivalent to return period. 7 3 0 0 0 0 Deep-convection and associated extremes such as lightning, convective gusts, tornadoes, and hail causes high amount of Noted. Have increased focus on these hazards. Hail was already considered damage. Besides, it is widely discussed whether these events have increased in past decades. Although this topic is of high in precipitation. In addition, small-scale wind events are newly considered relevance, it is only marginally discussed in SREX. Therefore, I suggest including a section, e.g. "3.4.5. Thunderstorm-related in 3.3.3. extremes" (Kunz, Michael, Karlsruhe Institute of Technology (KIT)) 8 3 0 0 0 0 Emphasis is very much on large-scale and from an atmospheric perspective (climate, land-atmosphere) rather than a more Do not understand comment. There is already considerable focus on balanced climate-hydrology section. (van Lanen, Henny A.J., Wageningen University) floods, droughts, etc. 9 3 0 0 0 0 The regions used for Africa (Figures 3.4 and 3.2) are appropriate and represent a good compromise between clarity and Noted. complexity (having too many regions). The definition captures the main areas of precipitation increase/decrease projected by GCMs, but with a little conflation of signals across West into Central Africa and East into the Horn, but I still think it's a reasonable breakdown to use (it's also consistent with earlier IPCC regions (Conway, Declan, University of East Anglia) 10 3 0 0 0 0 I have only made suggestions for where additional examples for Africa might be sourced. I think overall the chapter is very Thanks. The help with identifying African literature is appreciated. good and provides a well balanced review and discussion of evidence. Given that there are so many uncertainties with projections and issues about attribution of tnreds/extreme events it will be important that conclusions of other chapters in the report are consistent with these messages. (Conway, Declan, University of East Anglia) 11 3 0 0 0 0 I have reviewed sections 3.5.2 and 3.5.6, and I have no comments to these sections. (Rickenmann, Dieter, Swiss Federal Noted. Research Institute WSL) 12 3 0 0 0 0 This chapter states some essential statements that could be mentioned earlier in the report. Important chapter with Agreed. Much of the definitional discussions in Chapter 3 have been moved elements that should be evident in the introduction. Climate change does not necessarily mean more extreme weather to Chapter 1, in a text section being drafted by Robert Muir-Wood. events, which the other eight chapters make an impression of. (Asphjell, Torgrim, Climate and Pollution Agency (Norway)) 13 3 0 0 0 0 A risk framework requires hazard quantification. This chapter will not meet the expectations of engineers and risk analysts as Rejected. Far too much detail for a report of this kind, and especially in a it does not provide estimates of sea-level changes at particular locations worldwide. Ideally, I would like to see a general sea- chapter limited to 75 pages (to cover all extremes and impacts). level prediction model (or several models) as functions of time with coefficients, and tabulated coefficients provided by cities worldwide. The table would also include standard deviations that account for both historical randomness and epistemic uncertainty for predictions in the future. Such information would help users to develop risk profiles and examine solutions. (Ayyub, Bilal, University of Maryland) 14 3 0 0 0 0 Well written, clear and compact. No comments. (Bosello, Francesco, Fondazione Eni Enrico Mattei, Milan University \) Noted. 15 3 0 0 0 0 Some Tables and Figures such as Table 3.1and Fig. 1 - 4 should provide the main references. (Zhao, Zong-Ci, National Climate Noted. Where appropriate tables and figures now reference literature or Center) sections in the chapter from which conclusions are drawn. 16 3 0 0 0 0 An overall comment on this chapter is that it would benefit from a more explicit bringing together of process understanding Agreed. Subsections of 3.3-3.5 now include an introductory (short) where that is possible. By parititioning each type of extreme into observations, causes and projections, there is both some paragraph discussing mechanisms and process understanding (where repetition of information and some loss, in the latter case because there is not always clearly a sense of where the possible). observational, attribution and projection studies are all consistent in terms of the mechanisms behind particular changes. Examples of where discussion of mechanisms would be helpful include cold air outbreaks, page 35 line 12-15; different changes in extreme wind speeds in tropic and extra tropics page 45 lines 19-22; weakening of tropical circulations, page 48 25-27. (Stott, Peter, Met Office) Expert Review Comments Page 1 of 108 26 July - 20 September 2010 Do Not Cite, Quote, or Distribute IPCC SREX Chapter 3, FIRST-ORDER DRAFT From From To To # Ch Comment Response Page Line Page Line 17 3 0 0 0 0 It is recommended that for the better undrestanding of the text and reducing the vagues points ,more charts and figures be Now include more figures where appropriate, and replaced some from added. (Sehat kashani, Saviz, Atmospheric Sciences and Meteorological Research Center) previous draft that were taken from AR4. 18 3 0 0 0 0 It is recommended that in the literature review except the studies done by the developing countries more references related Agreed. Authors have tried to broaden the geographical coverage. to the studies done by other countries be added to it. (Sehat kashani, Saviz, Atmospheric Sciences and Meteorological Research Center) 19 3 0 0 0 0 All figures: are begging for zoom and recenter options (IPCC WGII TSU) Noted. Figures have been improved. 20 3 0 0 0 0 Throughout: There needs to be a serious discussion about the uncertainty terms in this chapter and whether it will use the Agreed. The chapter has been completely revised to match the new revised guidance. If it does, the sense one gets is that it should use likelihood in some places and confidence in many others. guidance on uncertainty This means that in some cases confidence is used, (IPCC WGII TSU) rather than likelihood. Overview is provided in new Section 3.1.5 21 3 0 0 0 0 Throughout: Almost none of the applications of calibrated uncertainty language in this chapter is transparent. For most, one Noted. We have tried to indicate more clearly than in previous IPCC gets a fuzzy feeling that the calibrated term is consistent with the sweep of the underlying material, but the stricy, reports, exactly how we have reached our assessments. We have continued quantitative, transparent basis of the assignment is almost never clear. (IPCC WGII TSU) to work on this, although we additionally needed to reframe everything that had been done, wtihin the new uncertainty guuidance framework. A full overview is provided in new Section 3.1.5 22 3 0 0 0 0 The WGI Co-Chairs and TSU firstly want to congratulate the Chapter 3 authors on an excellent FOD and acknowledge the Noted. obvious hard work involved in restructuring this Chapter. This has been very beneficial, and has led to a much improved and now very clear structure.