date: Fri, 10 Aug 2007 15:31:58 UT from: grlonline@agu.org subject: Review Received by Geophysical Research Letters to: p.jones@uea.ac.uk Content-Transfer-Encoding: binary Content-Type: multipart/alternative; boundary="_----------=_1186759918889555" MIME-Version: 1.0 X-Mailer: MIME::Lite 3.01 (F2.74; B3.07; Q3.07) Date: Fri, 10 Aug 2007 15:31:58 UT Message-Id: <1118675991820@gems> Dear Dr. Jones: Thank you for your review of "The phenomenological solar effect on climate" by Nicola Scafetta and Bruce West [Paper #2007GL031345], which we have safely received. A copy of this review is attached below for your reference. Thank you for your time and effort! Sincerely, Mark New Editor Geophysical Research Letters ------------------------------------------------------------------------ Science Category: Science Category 4 Presentation Category: Presentation Category C Annotated Manuscript: No Anonymous: Yes Referrals: No Confidential Referrals: Highlight: No Highlight: ABSOLUTELY NOTHING! Publishing this will generate a number of comments, plus irate letters from the three earlier reviewers Formal Review: Review of Scafetta and West I am a new reviewer and have been sent the revised submission plus the responses to the previous reviews. I began by reading the revised paper, then had a relatively quick look through the earlier comments and responses. My overall impression of that the paper is that it shouldn't be published. It makes too many claims that aren't justified, and seems more an exercise in curve fitting (the arm waving one of the earlier reviewer's refers to). I have separated my comments into major and minor ones. Major comments 1. There are many other quotes from the 2007 IPCC report in various chapters. You seem to want to use the one from Ch 9 to justify the 0.1K response to the solar cycle since 1980. However, just look at the observations of global temperature and show the reader how you can justify this? EBMs get much smaller amplitudes and these are more realistic. The reason they are smaller is that they are also accounting for volcanic forcing of the climate system over the same time. There is only 26 years of data since 1980 and there are two major volcanic eruptions in 1982 and 1991 which were 9 years apart. I can't see how you can look at solar influences on the 11-year timescale over this short period and ignore volcanic forcing. The omission of volcanic forcing will come up again. 2. If EBMs (or even GCMs for that matter) are missing important processes then come up with mechanisms to show that they are important! It is no good just saying that something is missing in the models - prove it. This is all speculation. Modellers will be able to incorporate these aspects into climate models (probably in GCMs first) if the mechanism (amplification process) can be shown. It is circular to try and say this must be happening by looking at the global temperature data. 3. The point about GHG and TSI not being independent is not an issue on the timescale of the last few hundred years. It is an issue on the Ice Age timescale, but it isn't on this timescale. The GHGs in the atmosphere can be shown to be anthropogenic and not related to any feedbacks. 4. For global temperature data you have chosen the two extreme series (in terms of amplitude of changes) from the plethora of series that have reconstructed temperatures over the last 1000 to 2000 years. This is reasonable to give you a range, but have you considered that many of the others look more like the Mann series than Moberg's. So from the spread of the various series (see IPCC Ch 6) Mann's series is more likely to be nearer the truth. There are also a number of statements in the paragraph about the description of the Mann series (Hockey Stick, Blade, Shaft) that are unnecessary. It is also not necessary at this stage to pre-judge the reader to say solar activity was low during the LIA (by the way you never define when this was, nor when it ended). 5. What is totally unreasonable about your use of these series is to patch the instrumental record from 1850 onwards on the end. You need to show the Mann and Moberg series through to their ends then add the instrumental data to the plot for comparison (after whatever smoothing you've applied). You don't say in Figure 1 how the series have been smoothed. You say you've given them the same mean over 1850-1899 (a reasonably good choice), but on what timescale? Did you also scale their interannual variances over this period as well? You could patch a few years on the end from about 1990, but don't do it the way you have. All the millennial reconstructions have different characteristics to the instrumental series. 6. Why are you bothering to use the Lean (2000) TSI reconstruction? Surely the Wang et al. (2005) paper supercedes this. I'm sure Judith Lean would agree with this being her latest thinking. If I write a new paper with a new series, I would expect people to use the new series, or use the old one of they are not up date with the literature. I wouldn't expect both to be used. This is different with the millennial reconstructions. There are various groups involved. With Lean it is the same person. She doesn't believe her 2000 paper now, so why do you still use it. You could use another person's reconstruction. 7. I've been saying to myself all along why ignore volcanic forcing. I see that the earlier referees mentioned the omission of other non-solar forcing. Volcanoes are the main one to my mind - there were a number of major volcanoes in the period from 1670 to 1700. Land-use change is much more uncertain and likely to be much smaller. Smoothing the proxy temperature reconstructions doesn't negate volcanism (as the effects are episodic) when events occur regularly. There are a number of volcanic forcing series that can be used. 8. One of the other arguments of Reviewer 4 is very compelling, but completely dismissed by the authors. This is the implication of saying the Moberg series is better than Mann and what this means for the period before 1600. I know the sunspot observations don't exist before this time, but there are beryllium and carbon-14 indices that say something about solar variability on longer timescales. They don't suggest that solar output was that much higher in Medieval times to explain the high temperature levels Moberg has then. If I were the authors, I would re-read Moberg's paper to see what the low frequency for the last 2 millennia is based on. I wouldn't want to put any faith in these proxies ability to record low-frequency temperature variations - a feature that cannot be assessed at all against instrumental temperature records. Minor comments 1. Putting the word 'Phenomenonological' in the title wasn't a good start. It isn't a great word and is repeated several times in the abstract. 2. A reference shouldn't be in the abstract. Also the IPCC (2007) report has with each chapter indicated how it should be cited. Just giving the page number is not appropriate. Why not refer to it as requested by IPCC. 3. The first sentence of the Introduction is not a good start. It needs a reference. The SPM of the AR4 IPCC report doesn't think there is much of a debate. They said they were 90% certain. Isn't this good enough in your mind. That there is an anthropogenic contribution is what is important. 4. With Figure 1, I can't see where the amplitudes of 0.2 and 0.8 K are plucked from. 5. I have said earlier, but when was the LIA. I know it is not defined at all well. It is far simpler to use calendar dates than pejorative terms like LIA and MWP. By their name they convey messages to the reader. Dates don't. 6. You seem to want to ignore Fröhlich's PMOD series that adjusts the ACRIM series. It seems as though throughout the paper you want to take the series - solar and millennial temperature that go along with your preconceptions. I can see you're trying to use different series to accommodate the possible ranges of the various series, but if Frölich and Lean are right, then from solar alone Moberg must be wrong.