Tuesday, December 13, 2011


From: Kevin Trenberth <trenbert@cgd.ucar.edu>
To: tom crowley <tcrowley@duke.edu>
Date: Fri, 12 Mar 2004 11:22:56 -0700
Cc: Chick Keller <cfk@lanl.gov>, Richard Somerville <rsomerville@ucsd.edu>, Tom Wigley <wigley@cgd.ucar.edu>, "Howard Hanson, LDRD" <hph@lanl.gov>, "James E. Hansen" <jhansen@giss.nasa.gov>, Michael Schlesinger <schlesin@atmos.uiuc.edu>, Phil Jones <p.jones@uea.ac.uk>, Thomas R Karl <Thomas.R.Karl@noaa.gov>, Mike MacCracken <mmaccrac@comcast.net>, Ben Santer <santer1@llnl.gov>, thompson.4@osu.edu, rbradley@geo.umass.edu, mhughes@ltrr.arizona.edu, Keith Briffa <k.briffa@uea.ac.uk>, Tim Osborn <t.osborn@uea.ac.uk>

I agree with Tom: I sent you (without copying others) a whole host of

tom crowley wrote:

> For goodness sakes, I don't know where to start - let me just make one
> point with respect to solar - solar projects onto the GHG signal in
> the 20th c. so solar cannot be distinguished during that time. if one
> were to independently correlate solar and GHG with temp. since 1750,
> solar would "explain" about 75% of the variance, GHG about 70% - a
> spectacular 140% of the variance explained!
> the only way to evaluate solar is to look at intervals when GHG was
> not changing and solar was - the preanthropogenic interval - perhaps
> the most comprehensive evaluation of the solar effect is in the
> attached paper, where it is quite clear that solar effect is either
> negligible or just barely significant, ie., 5-10% of the decadally
> scaled variance.
> with respect to the MWP all you have to do is plot the data up and
> compile them - the numbers don't work out as being warmer than the
> present - at best approaching or slightly exceeding mid-20th c. the
> reason is that is was warm at different times. Soon and Baliunas of
> course never showed this - but if you actually look at the damn data
> and plot up, the same answer as I stated above keeps showing up, over
> and over.
> with respect to UAH, there are now two other reconstructions that show
> otherwise.
> enough, this is like trying to convert someone with one religion to
> another.
> tom
> Chick Keller wrote:
>> Richard and Friends,
>> thanks for the point of view. I'll put some of this into my
>> presentation.
>> However, it won't wash when facing critics head-on.
>> Their latest arguments are more subtle. Their main point is that
>> their counter information hangs together into a logically coherent
>> picture.
>> Models: no real finger print that distinguishes AGHG forcings from
>> others! Models using AGHG forcings predict warming is function of
>> latitude yet the Arctic is hardly warming (north of ~^65�N), and high
>> latitude Antarctic (excepting for the peninsula) is actually cooling
>> slightly.
>> Models: As you say need AGHG forcings to simulate last 30 years of
>> observed warming. But, they counter, UAH satellite reductions show
>> no such warming so don't need AGHG forcing (or at least don't need
>> effects of positive feedbacks and just increases in AGHGs don't cause
>> so much warming).
>> Solar forcing--not able to generate last 30 years of observed
>> warming. Same counter as last one--"See, they say, no increased
>> solar in last 25 years is consistent with no warming!!
>> Also, since no warming since 1945, MWP most likely to have been as
>> warm as now and thus sun can indeed explain (with proper lags)
>> observed warming thus far.
>> Their model--climate varies depending on solar activity. all
>> observations are consistent with this.
>> Models predict that any surface warming will be seen in the
>> troposphere. Since UAH satellite reduction shows no such warming--1.
>> models are wrong and/or no warming at surface just lousy observations.
>> 2. If no warming at surface in last 30 years AGHG forcing predictions
>> by models is incorrect probably due to poor cloud/water vapor
>> modeling--no positive feedbacks to speak of.
>> Sooooo, you can say all you want that all the prestigious societies
>> and folks say it's AGHGs, but they've been bamboozled by a few of
>> elitist scientists. As long as satellites show no recent warming,
>> the entire AGHG hypothesis collapses, not because multi-atomic
>> molecules don't cause the atmosphere to be more opaque, but because
>> there are no positive feedbacks which the models need to get the
>> "right" answer.
>> So, what I need is strong evidence that the surface record is indeed
>> correct (UHI effect is small, and marine boundary layer approximation
>> is correct).
>> Now, Richard, toss in large effects of land use changes and of black
>> soot forcing changing earth's albedo, and you now have additional
>> forcings which may be causing warming but can't be countered by
>> reducing AGHGs.
>> Soooo, it still ain't all that easy to convince an audience that the
>> Singer's of this world aren't on to at least part of the problem.
>> AND keep in mind that increased CO2 is good for us--more agriculture,
>> etc.
>> Nope it just ain't that easy. So any information--graphics, etc on
>> these issues will be greatly appreciated.
>> Regards to all,
>> chick
>> Hi Chick and friends,
>> Good to hear from you, Chick. I'm busy, like all of us, and
>> responding to Singer is not my cup of tea, so I'm glad you and others
>> are willing. I hate to be in the same room with him, frankly. He's
>> a third-rate scientist and is ethically challenged, to say the least.
>> From others on your email list, I am sure you will receive tons of
>> useful information. However, I think your entire basic strategy for
>> confronting Singer might not be optimal. Sometimes the most pressing
>> issues in the research community, or the most interesting questions
>> scientifically, are not necessarily the best ways to carry on the
>> public conversation. I am thinking in particular of your statement:
>> "Perhaps the most important is that satellites don't show much
>> warming since 1979 and disagree substantially with the surface
>> record, which must then be incorrect. Were we able to resolve this
>> conundrum, I think most of the other objections to human generated
>> climate change would lose their credibility."
>> For what it's worth, here's my take on your approach. I
>> respectfully disagree with you that hammering away on reconciling the
>> MSU data with radiosonde and surface data is the right way to go in
>> dealing with the Fred Singers of the world. Even though much of the
>> differences may now be apparently explained, it's still a terribly
>> messy job. The satellite system wasn't designed to measure
>> tropospheric temperatures, the calibration and orbital decay and
>> retrieval algorithm and all the other technical issues are ugly, and
>> nobody knows how much the lower stratospheric cooling ought to have
>> infected the upper troposphere, among other points one might make.
>> No matter what one does on trying to make the MSU data tell us a
>> clean story, there are remaining serious uncertainties. That's
>> basically what the NAS/NRC study chaired by Mike Wallace concluded,
>> and it's still true, in my view. Plus the data record is so short.
>> In addition, as you say, you are retired, and research on these
>> things is not what you have first-person experience with, so when you
>> try to study up on the latest published results, you're at a
>> disadvantage compared with the Singers of the world, whose full-time
>> job is to cherry-pick the literature for evidence to support their
>> preconceived positions.
>> One of the tactics of the skeptics is to create the impression among
>> nonscientists, especially journalists, that the entire science of
>> climate change rests on the flimsy foundation of one or two lines of
>> evidence, so that casting doubt on that foundation ought to bring
>> down the entire structure. For temperature, that approach is clearly
>> behind the attacks on the "hockey stick" curve over the last 1,000
>> years or the satellite vs. in situ differences over the last 25
>> years. Refuting the errors of the papers by Soon and Baliunas or by
>> McIntyre and Mckitrick doesn't faze these people. They just shift
>> their ground and produce another erroneous attack. Their goal is not
>> to advance the science, but to perpetuate the appearance of
>> controversy and doubt.
>> I don't think the skeptics should be allowed to choose the
>> battlefield, and I certainly don't think the issue of whether
>> anthropogenic influences are a serious concern should be settled by
>> looking at any single data set. I do think the IPCC TAR was right to
>> stress that you simply can't plausibly make GCMs replicate the
>> instrumental record without including GHGs (and aerosols). I also
>> think the recent AGU and AMS public statements, which you will
>> doubtless find on their web sites, are right on target. Many of us
>> were pleasantly surprised that our leading scientific societies have
>> recently adopted such strong statements as to the reality and
>> seriousness of anthropogenic climate change. There really is a
>> scientific consensus, and it cannot be refuted or disproved by
>> attacking any single data set.
>> I also think people need to come to understand that the scientific
>> uncertainties work both ways. We don't understand cloud feedbacks.
>> We don't understand air-sea interactions. We don't understand
>> aerosol indirect effects. The list is long. Singer will say that
>> uncertainties like these mean models lack veracity and can safely be
>> ignored. What seems highly unlikely to me is that each of these
>> uncertainties is going to make the climate system more robust against
>> change. It is just as likely a priori that a poorly understood bit
>> of physics might be a positive as a negative feedback. Meanwhile,
>> the climate system overall is in fact behaving in a manner consistent
>> with the GCM predictions. I have often wondered how our medical
>> colleagues manage to escape the trap of having their entire science
>> dismissed because there are uncured diseases and other remaining
>> uncertainties. Maybe we can learn from the physicians.
>> People on airplanes, when they find out what I do for a living,
>> usually ask me if I "believe in" global warming. It's not religion,
>> of course. What I actually tend to believe in, if they really wanted
>> to try to understand, is quantum mechanics. CO2 and CH4 and all
>> those other interesting trace gases have more than two atoms, and
>> that fact simply has inescapable consequences. You just can't keep
>> adding those GHG molecules indefinitely without making the atmosphere
>> significantly more opaque in the IR. The "debates" in the reputable
>> research community are all quantitative. If skeptics don't worry
>> about doubling, they ought to be pressed to tell us why they are
>> unconcerned about tripling or quadrupling or worse. That's where the
>> planet is headed. The fact that remote sensing and model building
>> are hard work, and that much remains to be done, shouldn't be allowed
>> to obscure the basic obvious facts.
>> Bonne chance et bon courage,
>> Richard

Kevin E. Trenberth e-mail: trenbert@ucar.edu
Climate Analysis Section, NCAR www.cgd.ucar.edu/cas/
P. O. Box 3000, (303) 497 1318
Boulder, CO 80307 (303) 497 1333 (fax)

Street address: 1850 Table Mesa Drive, Boulder, CO 80303


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