date: Mon, 30 Mar 2009 22:12:01 UT
subject: Review Received by Geophysical Research Letters
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(F2.74; B3.07; Q3.07) Date: Mon, 30 Mar 2009 22:12:01 UT Message-Id: <9312384511218@gems>
Dear Dr. Jones:
Thank you for your review of "How Will Earth's Surface Temperature Change in Future
Decades?" by Judith Lean and David Rind [Paper #2009GL038131], which we have safely
received. A copy of this review is attached below for your reference.
Thank you for your time and effort!
Geophysical Research Letters
Science Category: Science Category 2
Presentation Category: Presentation Category B
Annotated Manuscript: No
In its present it needs significant changes.
Review of Lean and Rind
I have a number of major and some minor concerns. If all my major comments can be addressed
and #4 removed, I'd recommend acceptance. In its present state, the paper is not
Major - all are important.
1. The second sentence of the introduction falls into the same trap that those that have
questioned the reality of global warming have done. If there is a trend from 2002 to 2008
it isn't significant, it isn't even a decade! You need to write this and the next sentence
differently. You don't want to have to refer to the non-scientific statements on blogs and
2. The use of the word model at the top of p4 is confusing. What you mean here is the
statistical or empirical model from the regression analyses.
3. Can you state the amplitude of the solar effect (from solar max to min), just so I don't
have to estimate it from Figure 1. More importantly can you explain in some detail (i.e.
justify) the ups and downs in the green curve in Figure 1 during periods of solar maxima?.
4. To claim that Europe warms following volcanoes you need some references. It may cool
slightly in winter, but it isn't significant. It cools in Europe in summers. See Jones et
al. (2003). It's not significant because samples are small and winter temperatures are
highly variable. You are looking at annual temperatures. Here, any winter warming (that
isn't significant) is countered by summer cooling (that is again insignificant). I'd remove
any reference to European warming. If you want to keep it in prove it, and at the same time
show where Jones et al (2003) got it wrong.
5. The numbers in the paragraph on p6, lines 1-10 need some error ranges, however difficult
6. The summary section isn't really a summary section. It contains many of the caveats that
should have been in the main text.
7. In the regional fits (Figure 2) do you allow the lags to vary spatially? If you do this
needs an extra section to show that the varying lags are in agreement spatially.
1. It is important to define what near-term is.
2. line 25 of p1, do you really mean decades on this line. Is it not just a decade or at
3. When you say 'normalization' on line 9 of p2 you probably mean 'initialization'?
4. Coverage is just as good back to 1951. There is no rationale for starting in 1981. I see
later that the regressions are calculated over 1970-99. The base period and the regression
period should be brought together.
5. It would be possible to run the regressions over the period from 1951-70 to see if the
regression weights stand up. Another use of the 1951-70 period would be use the regression
estimate (from the fit from 1970-99) to calculate global mean temperatures and then compare
with those measured. This latter use an excellent way of validating the regression weights.
6. The Brohan et al (2006) data on p3 is called HadCRUT3(v) and it is a joint venture
between CRU and the Hadley Centre. As you've got the data from the CRU web site, you can
see that there are a number of datasets there. They have names, so use them. There is no
such thing as CRU data, just like there isn't a single GISS model or data!
7. For projections/forecasts you could do a range of possible ENSO and volcanic
projections. Could do a worst case, which might be a volcano coinciding with a La Nina
8. IPCC's 0.2 on line 24 of p4 was probably rounded. Your 0.17 would round to the same
number. I wouldn't make a big thing of the difference.
9. No idea what 'past is prologue' on p6, line 23 means.
Jones, P.D., Moberg, A., Osborn, T.J. and Briffa, K.R., 2003: Surface climate responses to
explosive volcanic eruptions seen in long European temperature records and mid-to-high
latitude tree-ring density around the Northern Hemisphere, In (A. Robock and C. Oppenheimer
Eds.) Volcanism and the Earth's Atmosphere. American Geophysical Union, Washington D.C.