From	Mike Hulme	Date	Mon Jun 2 13:49:07 2003
To	Pritchard, Norah
Subject	Re: IPCC WG2 AR4 draft outlines - WGII outline & Chapters 2 and 13
Dear Osvaldo and Martin, It is very difficult to make considered input into this process at such short notice. I received the emails Wednesday afternoon, just before being away from the office for 48 hours. I also am not fully aware of the process into which this is fitting and it is the first time I have seen the WGII outline. I do however make some comments on the following: The WGII outline Chapter 2 on data etc. Chapter 13 on critical damage etc. WGII outline ----------------- Key Questions: there is, in analytical terms, very little difference between the 2nd and 4th key question you pose. The impacts under unmitigated CC (Q2) are not in any fundamental way different from the impacts under mitigated CC (Q4). 2degC warming, for example, will give broadly the same impacts whether this occurs because of strong CC policy intervention or whether it occurs because of low carbon development paths. What matters more for impacts is the rate of CC and what matters more for how important those impacts are is the development path pursued. I think this distinction between mitigated and unmitigated CC is tenuous and unhelpful. This has a bearing on the later discussions about stabilisation (where "stabilisation" is usually assumed to be, indeed often synonymous with, the result of mitigative action; actually (quasi-) stabilisation, at different levels, can occur in a world with relatively little direct CC mitigation policy). The progression through the sections follows a rather linear and reductionist model - observed impacts, future impacts, adaptation,regions. I would have liked to have seen an early opening chapter on the nature of the dynamic relationship between climate and society (before we even start talking about climate change), this being able to bring out notions of vulnerability and adaptation - both fundamental to put on the table before we start thinking about future climate change and how important it is. This could also point out that "critical" damage is already being caused by climate and climate variability. Under your structure, the observed impacts section (II) should surely parallel the later future impacts section (III) in terms of sectors/themes. There are only 4 themes in section II, yet 6 (different) themes in section III. Why for example is nothing said about observed impacts on urban infrastructure or on coasts? The asymmetry between these section sub-themes is itself perhaps revealing. It seems odd that adaptation is to be addressed in all the thematic chapters in Section III *as well as* in a separate later chapter on adaptation. This situation is ripe for overlap and redundancy. Our understanding of adaptation in any case should be brought in right at the beginning (see above). The avoiding critical damage chapter suffers from the same problem identified above - what matters is whether and how such exceedance rates can be identified, not whether they result from either a mitigated or an unmitigated scenario - this academic distinction cannot be sustained in the real world. The regional section is in danger of repeating the mistake in the TAR, again leading to dispersion of effort and redundancy. My suggestion would be *not* to assess all new regional knowledge (again; very turgid), but instead to produce a much more streamlined section focusing on a few regional/local case studies that illustrate sharply many of the (integrating) themes introduced earlier - vulnerability, adaptation, criticality, impacts. Deliberately seek to be selective and not comprehensive. I also do not see how the WGII chapters will be co-ordinated with the 5 cross-cutting papers identified here - again, there seems much scope for duplicitous effort and redundancy or even contradiction. And since the cross-cutting papers are really the interesting and useful ones, this suggests to me that the old traditional WG structure of IPCC is now deeply flawed (as I have said more than once before in public). Chapter 2 - Assumptions, etc. --------------------------------------------- First question to raise is what is WGI doing in this regard? I cannot comment sensibly without knowing how WGI will tackle questions of scenarios and future projections. In section 2.3, 4th bullet: how relevant really are these "Stabilisation scenarios (mitigation)"? At the very least IPCC must clear up this issue about whether stabilisation is a short-hand for mitigation (as implied here). This is potentially misleading, since stabilisation can occur in many different worlds, by no means all of them worlds with strong CC mitigation policies. Continuation of this thinking means reality is being forced to accommodate the arbitrary thinking of the UNFCCC rather than UNFCCC being forced to take account of reality. Also in this bullet is "Impacts of extreme climate events". Why are impacts being looked at here? Surely this is totally misplaced. What is important are scenarios - of whatever origin and methodology - that embed within them changes in the character of "extreme" weather and how we describe such changes. We should not separate this out as a separate issue surely. Section 2.4 (the second appearance) confuses me. Much of this material appears earlier in 2.3, thus characterisations of future conditions is what 2.3 is about and also the projected changes in key drivers is what the scenarios part of 2.3 is all about. Do you mean to differentiate between methodology (2.3) and outcomes (2.4b)? And as always you will run into the problem of summarising what scenarios actually *are* assumed in this report - is there to be an IPCC 4AR standard scenario(s) that all should use? I suspect not. Resolving this problem gets to the heart of the structural problem with IPCC. Different people will use different assumptions. Chapter 13 - Critical Damage ... ------------------------------------------------ This outline was almost unintelligible to me! For example having read the opening aims and scope statement several times, I an still not clear about the approach this chapter is taking. Sections 13.2 and 13.3 are also extremely unclear as is section 13.4. I think someone needs to do some clearer thinking about this chapter before sending it out for people to comment on. I have my own views on this, but at such short notice and without knowing the agreed IPCC process I'm not going to write the chapter outline for you. Inter alia, the chapter should address the following: - different paradigms for defining "critical"; will vary by sector, culture, etc. - distinction between external (pronounced) definitions of critical and internal (experienced/perceived) definitions - relationship between adaptive capacity and "critical" rates of change - dependence of critical thresholds on sector and spatial scale - reversibility (or not) of critical damage ... and if the use of "critical" is a euphemism for "dangerous" then it is not very subtle - people will see through this. What is the difference between critical and dangerous? Professor Mike Hulme Tyndall Centre At 14:32 28/05/2003 +0100, you wrote: Dear Mike We are now developing chapter outlines for the Fourth Assessment Report of the IPCC and we write to ask if you will help us in this task. Enclosed is a one-page outline of the proposed chapter on Assumptions, Data and Scenarios, which we would like you to adjust and expand (but not to more than one and a half pages in all, please). The overall list of proposed topics to be covered in the assessment is also attached. We would like to make the next revision to the outline in a few days so could you please return your outline to Norah Pritchard << ipccwg2@metoffice.com >> at the WGII Techical Support Unit at the UK Met Office's Hadley Centre not later than 2nd June? The process of designing the Fourth Assessment and selecting authors is different from previously. This time the authors will not be nominated by governments and then selected until *after* the outline has been approved by IPCC Plenary this November. The outlines are there fore being widely commented on between now and mid-September, when they will be finalised. We consider your input at this time to be most important. We appreciate that you are busy, but urge that you give a few minutes to this crucial task. In another message we will be writing for your suggestions regarding other experts to consult in the fields of Assumptions, Data and Scenarios. We look forward to hearing from you With thanks and kind regards, Osvaldo Canziani and Mart in Parry Co-Chairs, IPCC Working Group II (Vulnerability, Impacts and Adaptation) Dr Martin Parry, Co-Chair Working Group II (Impacts and Adaptation), Intergovernmental Panel on Climate Change, Hadley Centre, UK Met Office, London Road, Bracknell RG12 2SY, UK. Tel direct: +44 1986 781437 Tel switchboard: +44 1344 856888 direct e-mail: parryml@aol.com e-mail for WGII Technical Support Unit: ipccwg2@metoffice.com <> <>