The Climate Science Isn't Settled -- RICHARD S. LINDZEN -- WSJ
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Eric Swanson
Dec 2, 2009, 10:10:50 AM12/2/09
to globalchange
If there is anyone out there in Global Change Land still following
this group, you might be interested in the op-ed piece that Dr.
Richard Lindzen wrote for the Wall Street Journal on 30 November.
http://online.wsj.com/article/SB10001424052748703939404574567423917025400.html
In it, one of his points is a repeat of his claim that there is a
negative feedback due to clouds. He is apparently referring to his
Adaptive Iris hypothesis. His comments (heavily edited for brevity)
are:
“It is generally accepted that a doubling of CO2 will only produce a
change of about two degrees Fahrenheit if all else is held
constant........current climate models predict much higher
sensitivities. They do so because in these models, the main greenhouse
substances (water vapor and clouds) act to amplify anything that CO2
does. This is referred to as positive feedback. But as the IPCC notes,
clouds continue to be a source of major uncertainty in current
models...............It turns out that increased thin cirrus cloud
coverage in the tropics readily resolves the paradox but only if the
clouds constitute a negative feedback. In present terms this means
that they would diminish rather than enhance the impact of CO2.....”
He also gives an example of a negative feedback, discussing a period
some 2.5 billion years ago when the Sun’s output is thought to have
been 20-30% less than now. He claims that the negative feedback of
clouds might explain the apparent lack of freezing of the oceans at
the time.
I’ve often wondered about Lindzen’s negative cloud feedback. My main
issue with his hypothesis is the question of Ice Ages. We know with
near certainty that over the past 3 million years or so, the Earth’s
climate has been dominated by Ice Age conditions. We are currently
experiencing an Interglacial, that is, a warm period during which the
massive ice sheets have melted and the Earth’s average temperature is
a few degrees warmer than the temperature during the Ice Ages.
So, I take the opportunity to ask a rather obvious question: If the
feedback from high clouds is strong enough to have prevented freezing
during the period of low solar output Lindzen mentions, how is it that
the Earth warmed enough for the ice sheets to have melted. Wouldn’t
the negative feedback have prevented the warming which led to the
melting of the ice? Looking at the other end of the cycle of Ice
Ages, if that cloud feedback was strong enough to offset the low solar
output, what was the cause of the freezing which terminated the last
Interglacial, the Eemian, roughly 120,000 years ago (and all the other
Interglacials over the past 3 million years as well)??
I think Dr. Lindzen may have destroyed his own hypothesis in his op-ed
piece....8-)
E. S.
this group, you might be interested in the op-ed piece that Dr.
Richard Lindzen wrote for the Wall Street Journal on 30 November.
http://online.wsj.com/article/SB10001424052748703939404574567423917025400.html
In it, one of his points is a repeat of his claim that there is a
negative feedback due to clouds. He is apparently referring to his
Adaptive Iris hypothesis. His comments (heavily edited for brevity)
are:
“It is generally accepted that a doubling of CO2 will only produce a
change of about two degrees Fahrenheit if all else is held
constant........current climate models predict much higher
sensitivities. They do so because in these models, the main greenhouse
substances (water vapor and clouds) act to amplify anything that CO2
does. This is referred to as positive feedback. But as the IPCC notes,
clouds continue to be a source of major uncertainty in current
models...............It turns out that increased thin cirrus cloud
coverage in the tropics readily resolves the paradox but only if the
clouds constitute a negative feedback. In present terms this means
that they would diminish rather than enhance the impact of CO2.....”
He also gives an example of a negative feedback, discussing a period
some 2.5 billion years ago when the Sun’s output is thought to have
been 20-30% less than now. He claims that the negative feedback of
clouds might explain the apparent lack of freezing of the oceans at
the time.
I’ve often wondered about Lindzen’s negative cloud feedback. My main
issue with his hypothesis is the question of Ice Ages. We know with
near certainty that over the past 3 million years or so, the Earth’s
climate has been dominated by Ice Age conditions. We are currently
experiencing an Interglacial, that is, a warm period during which the
massive ice sheets have melted and the Earth’s average temperature is
a few degrees warmer than the temperature during the Ice Ages.
So, I take the opportunity to ask a rather obvious question: If the
feedback from high clouds is strong enough to have prevented freezing
during the period of low solar output Lindzen mentions, how is it that
the Earth warmed enough for the ice sheets to have melted. Wouldn’t
the negative feedback have prevented the warming which led to the
melting of the ice? Looking at the other end of the cycle of Ice
Ages, if that cloud feedback was strong enough to offset the low solar
output, what was the cause of the freezing which terminated the last
Interglacial, the Eemian, roughly 120,000 years ago (and all the other
Interglacials over the past 3 million years as well)??
I think Dr. Lindzen may have destroyed his own hypothesis in his op-ed
piece....8-)
E. S.
Tom Adams
Dec 4, 2009, 8:32:52 AM12/4/09
to globalchange
This is not a new objection, here it is almost 6 years ago:
http://www.realclimate.org/index.php/archives/2006/02/richard-lindzens-hol-testimony/
I suppose Lindzen may have responded to this objection, since it has
been around for a while, but I can't find his response.
This article implies that Lindzen thinks that a higher-than-expected
albedo forcing of the ice sheets could be the source of the extra
forcing required. Or is it a straw man who thinks that? Not sure.
Also the article implies that Lindzen (or a straw man) thinks it was
not so cold as most climatologists think it was during the glacials.
http://www.realclimate.org/index.php/archives/2006/02/richard-lindzens-hol-testimony/
I suppose Lindzen may have responded to this objection, since it has
been around for a while, but I can't find his response.
This article implies that Lindzen thinks that a higher-than-expected
albedo forcing of the ice sheets could be the source of the extra
forcing required. Or is it a straw man who thinks that? Not sure.
Also the article implies that Lindzen (or a straw man) thinks it was
not so cold as most climatologists think it was during the glacials.
Eric Swanson
Dec 4, 2009, 6:44:41 PM12/4/09
to globalchange
Sure enough, Real Climate posted an article last evening about the op-
ed piece.
http://www.realclimate.org/index.php/archives/2009/12/unsettled-science/#more-2187
I suppose I should read Lindzen's GRL paper, mentioned in an earlier
thread.
ed piece.
http://www.realclimate.org/index.php/archives/2009/12/unsettled-science/#more-2187
I suppose I should read Lindzen's GRL paper, mentioned in an earlier
thread.
Alastair
Dec 5, 2009, 6:33:41 AM12/5/09
to globalchange
On Dec 4, 11:44 pm, Eric Swanson <e_swan...@skybest.com> wrote:
> Sure enough, Real Climate posted an article last evening about the op-
> ed piece.
>
>
> I suppose I should read Lindzen's GRL paper, mentioned in an earlier
> thread.
The point is that Lindzen is wrong and he is right!
> I suppose I should read Lindzen's GRL paper, mentioned in an earlier
> thread.
Clouds do drive the climate but not just cirrus clouds in the
tropics.
As everyone knows that CO2 is saturated. What this means is that if
the surface temperature increases then the planet cannot return to
balance by emitting more radiation in the CO2 band. But the water
vapour bands are saturated too, so almost OLR is fixed! The way the
climate can gets into balance is not by altering the OLR to space, but
by changing the net incoming radiation with alterations in albedo
through cloud cover. But loss of the Arctic sea ice will alter the
albedo, so the planet will not return to balance until global climate
is such that the albedo lost by the melting of the Arctic ice is
replaced by additional cloud cover.
How high will the global temperature have to go for this to happen?
Cheers, Alastair.
Tom Adams
Dec 7, 2009, 8:30:54 AM12/7/09
to globalchange
On Dec 4, 6:44 pm, Eric Swanson <e_swan...@skybest.com> wrote:
> Sure enough, Real Climate posted an article last evening about the op-
> ed piece.
>
>
> I suppose I should read Lindzen's GRL paper, mentioned in an earlier
> thread.
I don't think the paper addresses your objection:
> I suppose I should read Lindzen's GRL paper, mentioned in an earlier
> thread.
http://www.drroyspencer.com/Lindzen-and-Choi-GRL-2009.pdf
David B. Benson
Dec 8, 2009, 7:17:57 PM12/8/09
to globalchange
Please read the summary of the 1979 Charney et al. NAS/NRC report on
CO2 and climate:
http://books.nap.edu/openbook.php?record_id=12181&page=1
to note that indeed an additional 30 years of research has changed
almost nothing. I'd say that part of the science is settled.
CO2 and climate:
http://books.nap.edu/openbook.php?record_id=12181&page=1
to note that indeed an additional 30 years of research has changed
almost nothing. I'd say that part of the science is settled.
hgerh...@yahoo.co.uk
Dec 10, 2009, 8:50:17 AM12/10/09
to globalchange
The Early faint Sun paradox is interesting. Having done a bit of
reading about it, it seems that one plausible explanation is that the
steady increase in the Sun's solar output may have been compensated by
a (less steady) decline in greenhouse gas concentrations, notably the
very powerful, but low concentration ones like methane.
Having said that, I still have trouble with the notion that forcings
always have the same level of feedbacks. I find it quite plausible on
the face of it that clouds, ice sheets, greenhouse gases etc.
sometimes could act as a near perfect thermostat, and sometimes they
might act to amplify even the tiniest of external perturbations. So,
in the ice ages, a solar related external perturbation of virtually
nothing got amplified to 6C, and over a longer time scale, a massive
solar perturbation didn't get amplified, but rather regulated away by
the Earth system response.
What do I conclude from that about how the system might respond to a
perturbation now? Well, I clearly don't buy Lindzen's line that it's a
near certain fact that a few W/m2 will now give virtually no response.
But I also fail to see, where the certainty comes from that as James
Annan put it, climate sensitivity is 3C. By analogy with past climate
alone it's certainly plausible to expect both the possibility of
massive amplification and a virtually perfect thermostat.
So, maybe in the ice ages, cloud feedbacks due to ice sheets were very
different to how cloud feedbacks might operate due to a forced
increase in CO2 concentrations together with massive aerosol
injections plus quite a few land use changes. And, while those
feedbacks might be thermostat like now, why shouldn't there be a
threshold, where clouds suddenly become strongly amplifying instead?
reading about it, it seems that one plausible explanation is that the
steady increase in the Sun's solar output may have been compensated by
a (less steady) decline in greenhouse gas concentrations, notably the
very powerful, but low concentration ones like methane.
Having said that, I still have trouble with the notion that forcings
always have the same level of feedbacks. I find it quite plausible on
the face of it that clouds, ice sheets, greenhouse gases etc.
sometimes could act as a near perfect thermostat, and sometimes they
might act to amplify even the tiniest of external perturbations. So,
in the ice ages, a solar related external perturbation of virtually
nothing got amplified to 6C, and over a longer time scale, a massive
solar perturbation didn't get amplified, but rather regulated away by
the Earth system response.
What do I conclude from that about how the system might respond to a
perturbation now? Well, I clearly don't buy Lindzen's line that it's a
near certain fact that a few W/m2 will now give virtually no response.
But I also fail to see, where the certainty comes from that as James
Annan put it, climate sensitivity is 3C. By analogy with past climate
alone it's certainly plausible to expect both the possibility of
massive amplification and a virtually perfect thermostat.
So, maybe in the ice ages, cloud feedbacks due to ice sheets were very
different to how cloud feedbacks might operate due to a forced
increase in CO2 concentrations together with massive aerosol
injections plus quite a few land use changes. And, while those
feedbacks might be thermostat like now, why shouldn't there be a
threshold, where clouds suddenly become strongly amplifying instead?
David B. Benson
Dec 11, 2009, 7:10:38 PM12/11/09
to globalchange
On Dec 10, 5:50 am, "hgerhau...@yahoo.co.uk" <hgerhau...@yahoo.co.uk>
wrote:
> ... And, while those
http://geosci.uchicago.edu/~rtp1/ClimateBook/ClimateBook.html
and his co-authored CaltechWater.pdf
wrote:
> ... And, while those
> feedbacks might be thermostat like now,
This is implausible. See Ray Pierrehumbert's
http://geosci.uchicago.edu/~rtp1/ClimateBook/ClimateBook.html
and his co-authored CaltechWater.pdf
> why shouldn't there be a
> threshold, where clouds suddenly become strongly amplifying instead?
This, too, is implausible.
> threshold, where clouds suddenly become strongly amplifying instead?
James Annan
Dec 11, 2009, 8:58:56 PM12/11/09
to global...@googlegroups.com
There is a strong possibility of confusing two subtly different concepts here.
Firstly, with respect to the linear response to small changes in GHG
(especially CO2) forcing: it must be borne in mind that the forcing of
4W/m^2 is really very small compared to the range of changes that the
climate system already sees locally, which may be over a thousand
W/m^2 on a daily basis and at least 100 W/m^2 on a seasonal basis
(which is long enough for the large land masses and atmosphere to
reach local equilibrium given the sea surface temperature). To first
order, all responses to small perturbations are linear. This is also
supported by basically every model - we can occasionally create
threshold effects, especially on a regional basis, but it is hard to
create something that has a broad effect. One phenomenon I am aware
about in some models is a runaway warming that may be due to the
mis-specification of ozone in the stratosphere - briefly, the ozone
distribution is generally held fixed in space and if the tropopause
rises, this may result in "stratospheric" ozone appearing in the
troposphere where it buggers up the radiation code. Similarly, very
high GHG (10x) concentrations may invalidate the approximations in the
code. But we have good reasons to believe that the equilibrium
response to small increases in CO2 is near-linear, and the question is
merely regarding the slope of that line.
Now, when we are talking about substantially different forcing
mechanisms, especially large ice sheets, and also rather different
climate states - involving things like continental rearrangement and
appearance of the major mountain ranges, which may result in large
changes to the global climate state including things like dominant
weather patterns and the mean humidity of the atmosphere, the same
argument as above would very likely apply to modest CO2 perturbations
on top of that state (though the modelling support will be far thinner
simply because people aren't doing so many experiments), but the slope
of the linear response is likely to be different. In fact, our
modelling work (and that of other people) strongly supports the belief
that the background climate state does affect the response to co2
changes.
So while there may be some nonlinearity, ie a change in response as
the forcing changes, there is no reason to either think this is likely
to be a significant threshold, or that we are close to such a
threshold. People are looking at this (especially wrt N Atlantic
overturning circulation) but they seem to find it hard to get anything
interesting - even on this regional basis, let alone global.
James
2009/12/10 hgerh...@yahoo.co.uk <hgerh...@yahoo.co.uk>:
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Firstly, with respect to the linear response to small changes in GHG
(especially CO2) forcing: it must be borne in mind that the forcing of
4W/m^2 is really very small compared to the range of changes that the
climate system already sees locally, which may be over a thousand
W/m^2 on a daily basis and at least 100 W/m^2 on a seasonal basis
(which is long enough for the large land masses and atmosphere to
reach local equilibrium given the sea surface temperature). To first
order, all responses to small perturbations are linear. This is also
supported by basically every model - we can occasionally create
threshold effects, especially on a regional basis, but it is hard to
create something that has a broad effect. One phenomenon I am aware
about in some models is a runaway warming that may be due to the
mis-specification of ozone in the stratosphere - briefly, the ozone
distribution is generally held fixed in space and if the tropopause
rises, this may result in "stratospheric" ozone appearing in the
troposphere where it buggers up the radiation code. Similarly, very
high GHG (10x) concentrations may invalidate the approximations in the
code. But we have good reasons to believe that the equilibrium
response to small increases in CO2 is near-linear, and the question is
merely regarding the slope of that line.
Now, when we are talking about substantially different forcing
mechanisms, especially large ice sheets, and also rather different
climate states - involving things like continental rearrangement and
appearance of the major mountain ranges, which may result in large
changes to the global climate state including things like dominant
weather patterns and the mean humidity of the atmosphere, the same
argument as above would very likely apply to modest CO2 perturbations
on top of that state (though the modelling support will be far thinner
simply because people aren't doing so many experiments), but the slope
of the linear response is likely to be different. In fact, our
modelling work (and that of other people) strongly supports the belief
that the background climate state does affect the response to co2
changes.
So while there may be some nonlinearity, ie a change in response as
the forcing changes, there is no reason to either think this is likely
to be a significant threshold, or that we are close to such a
threshold. People are looking at this (especially wrt N Atlantic
overturning circulation) but they seem to find it hard to get anything
interesting - even on this regional basis, let alone global.
James
2009/12/10 hgerh...@yahoo.co.uk <hgerh...@yahoo.co.uk>:
> You received this message because you are subscribed to the Google Groups Global Change ("globalchange") newsgroup. Global Change is a public, moderated venue for discussion of science, technology, economics and policy dimensions of global environmental change.
>
> Posts will be admitted to the list if and only if any moderator finds the submission to be constructive and/or interesting, on topic, and not gratuitously rude.
>
> To post to this group, send email to global...@googlegroups.com
>
> To unsubscribe from this group, send email to globalchange...@googlegroups.com
>
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hgerh...@yahoo.co.uk
Dec 12, 2009, 2:06:46 PM12/12/09
to globalchange
> and his co-authored CaltechWater.pdf> why shouldn't there be a
Ok, so I went and had a look at the pdf and found these sentences
there:
"There is much indirect evidence that the water vapor feedback in
models is correct, and indeed no compelling reason has emerged to
doubt it. Nonetheless, it has proved difficult to articulate cleanly
and convincingly from basic principles exactly why one should have
confidence in this aspect of the models. If the atmosphere were
saturated at all levels, understanding water vapor feedback would
offer few challenges. The difficulty arises from the prevalence of
highly unsaturated air in the atmosphere."
That's not about clouds, which are clearly even more difficult to
understand, but the pdf is about water vapour and not about clouds.
I believe that we have limited knowledge about past changes in
relative humidity. There are no proxies for relative moisture as far
as I know. From what I've read, it's also been quite hard to prove the
constant relative humidity notion by recent observation of actual,
shorter term humidity trends in the atmosphere.
Some related links, that people may find interesting:
http://www.arm.gov/publications/proceedings/conf04/extended_abs/arking_a.pdf
(clouds as thermostats)
http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=1398
(circulation patterns acting as feedbacks in the case of arctic sea
ice)
David B. Benson
Dec 12, 2009, 8:56:24 PM12/12/09
to globalchange
On Dec 12, 11:06 am, "hgerhau...@yahoo.co.uk" <hgerhau...@yahoo.co.uk>
wrote:
> ...
Indeed so, except for a few obvious bits: assume a great supply of
CCNs (correct except possibly for the Southern Ocean and Antarctica).
Then if relative humidity goes up, clouds form and the moisture
precipitates out. If relative humidity goes down...
So measure global precipitation; it hasn't changed much at all in
over a quater century; ergo...
Now the GCMs do not assume a (nearly) constant relative humidity,
but rather attempt to resolve the underlying physics of the
atmosphere. Nearly constant relative humidity pops out of the
runs.
For a 2003 CE study of what more was needed at that time, see
http://www.nap.edu/catalog.php?record_id=10850#toc
My understanding is that most of those issues have been adequately
resolved; the current pressing mattrs are aerosols and ocean heat
uptake.
As for the more general point about sudden changes, the situation in
the arctic is certainly a reminder that the cryosphere is also
currently poorly understood; Jeff Masters certainly has a point!
wrote:
> ...
> I believe that we have limited knowledge about past changes in
> relative humidity. ...
Indeed so, except for a few obvious bits: assume a great supply of
CCNs (correct except possibly for the Southern Ocean and Antarctica).
Then if relative humidity goes up, clouds form and the moisture
precipitates out. If relative humidity goes down...
So measure global precipitation; it hasn't changed much at all in
over a quater century; ergo...
Now the GCMs do not assume a (nearly) constant relative humidity,
but rather attempt to resolve the underlying physics of the
atmosphere. Nearly constant relative humidity pops out of the
runs.
For a 2003 CE study of what more was needed at that time, see
http://www.nap.edu/catalog.php?record_id=10850#toc
My understanding is that most of those issues have been adequately
resolved; the current pressing mattrs are aerosols and ocean heat
uptake.
As for the more general point about sudden changes, the situation in
the arctic is certainly a reminder that the cryosphere is also
currently poorly understood; Jeff Masters certainly has a point!
Eric Swanson
Dec 13, 2009, 12:05:10 PM12/13/09
to globalchange
In your first referenced link, the author doesn't discuss ocean
currents. The East to West flow along the Equator in the Pacific is
well known. If the waters in the Western Pacific are warmer to begin
with, the energy flows would add to that underlying condition.
There's a mixed near the surface and short term fluctuations in
thermal energy don't make much difference. Then too, in the Eastern
Pacific, the La Nina phase brings colder sub-surface water to the
surface, which cools the air above.
Here's some graphics which shows the effects of the upwelling water
quite nicely.
Current anomaly:
http://www.osdpd.noaa.gov/data/sst/anomaly/2009/anomp.12.10.2009.gif
Archived October 2007
http://www.osdpd.noaa.gov/data/sst/anomaly/2007/anomp.10.8.2007.gif
E. S.
----------------------------------------------------
[cut]
currents. The East to West flow along the Equator in the Pacific is
well known. If the waters in the Western Pacific are warmer to begin
with, the energy flows would add to that underlying condition.
There's a mixed near the surface and short term fluctuations in
thermal energy don't make much difference. Then too, in the Eastern
Pacific, the La Nina phase brings colder sub-surface water to the
surface, which cools the air above.
Here's some graphics which shows the effects of the upwelling water
quite nicely.
Current anomaly:
http://www.osdpd.noaa.gov/data/sst/anomaly/2009/anomp.12.10.2009.gif
Archived October 2007
http://www.osdpd.noaa.gov/data/sst/anomaly/2007/anomp.10.8.2007.gif
E. S.
----------------------------------------------------
[cut]
Hank Roberts
Dec 13, 2009, 3:45:14 PM12/13/09
to globalchange
> everyone knows that CO2 is saturated
Well, no, a fairly small group of people assert that everyone knows
that in theory but it needed to be tested.
It has been now:
See: http://ams.confex.com/ams/Annual2006/techprogram/paper_100737.htm
Alastair
Dec 13, 2009, 5:28:35 PM12/13/09
to globalchange
They write:
"The experimental fluxes are simulated well by the FASCOD3 radiation
code. This code has been used to calculate the model predicted
increase in surface radiative forcing since 1850 to be 2.55 W/m2. In
comparison, an ensemble summary of our measurements indicates that an
energy flux imbalance of 3.5 W/m2 has been created by anthropogenic
emissions of greenhouse gases since 1850. This experimental data
should effectively end the argument by skeptics that no experimental
evidence exists for the connection between greenhouse gas increases in
the atmosphere and global warming."
I am not arguing "that no experimental evidence exists for the
connection between greenhouse gas increases in the atmosphere and
global warming." I am arguing that the heating effect is being under-
estimated, which rather agrees with their results that show an
increase of 3.5 W/m^2, 40% higher than the calculated value of 2.55 W/
m^2. In Table 4 of the Extended Abstract, for CO2 the measured
increase is 2.10 W/m^2, 60% higher that the model value of 1.30 W/
m^2. That hardly points to climate science being settled!
But I will have to study it a bit more closely because it seems to run
counter to my ideas :-(
Cheers, Alastair.
Alastair
Dec 15, 2009, 9:24:42 AM12/15/09
to globalchange
carefully now. They are arguing that there is an increase in back
radiation of 3.52 W m^-2 compared to 2.55 W m^-2 predicted by models.
This increase is mainly due to water vapour. But water vapour is
highly variable so that is unconvincing. Another major factor in the
increase is from other anthropogenic gases such as CFCs, which of
course will produce a new forcing. It is only CO2 that I claim is
effectively saturated, and only within the CO2 bands. In other words I
am claiming that any line broadening is not significant.
They have only one entry per table for measured CO2, unlike the other
gases (Why?) In Table 3a CO2 shows and increase of 3.8 W m^-2 up to
the year 2000, and Table 3b shows an increase of 0.0 W m^-2 up to the
year 1999. The later value agrees with what I claim, but the former
value does not. They make no attempt to explain the difference in the
two value and quote 2.10 W m^-2 as the Measured flux in Table 4, but
that is not even the average of the two values which is 1.90 W m-2.
Moreover, it is the colder winter season when the back radiation seems
to be greater.
Note that the "PAST" value is a modeled value. So they are comparing
the difference between a measured/modeled value with a modeled/modeled
value. Are they really claiming that by measuring the down-welling
radiation on two occasions (summer and winter) at only one
geographical location then they can deduce the changes in global
radiation over a period of nearly two centuries?
So, IMHO, a rather unsatisfactory paper, and that may explain why it
is appearing as an extension to a poster rather than as a peer
reviewed paper. I suspect that they could not get it published.
Perhaps someone would be prepared to defend them!
Cheers, Alastair.
, so I would comment on it here thought I would post and so am n a
Eric Swanson
Dec 16, 2009, 8:24:05 AM12/16/09
to globalchange
Here's an article from the NYT you might find interesting. I suppose
there are papers on the instrument data, though the AGU presentation
might be the first such release.
http://www.nytimes.com/2009/12/16/science/space/16carbon.html
Here's the title of the session presentation:
A41B-0084. Estimates of the water vapor climate feedback during the El
Niño Southern Oscillation. A. E. Dessler; S. Wong
Abstract:
We have estimated the strength of the water vapor feedback by
analyzing the changes in tropospheric specific humidity during El Niño
Southern Oscillation (ENSO) cycles. We do this analysis in climate
models and in two reanalysis products, the European Center for Medium-
Range Weather Forecasts Reanalysis (ERA40) and the NASA Modern Era
Retrospective-analysis for Research and Applications (MERRA). The
water vapor feedback during ENSO in the models ranges from 1.4 to 3.9
W/m^2/K, and in the ERA40 and MERRA it is 3.7 and 4.7 W/m^2/K,
respectively. Taken as a group, these values are higher than previous
estimates of the water vapor feedback in response to century-long
global warming, suggesting that the ENSO water vapor feedback may be
stronger than the water vapor feedback in response to long-term global
warming. We also examine the reason for the large spread in the ENSO-
driven water vapor feedback among the models and between the models
and the reanalyses. We show that the spread is not related to the
variation in the simulation of water vapor, but are due to differing
estimates of extratropical surface temperature variations during ENSO.
The models and the reanalyses show a consistent relationship between
the variations in the tropical surface temperature over an ENSO cycle
and the radiative response to the associated changes in q.
A link was also given to their J. Climate paper:
http://geotest.tamu.edu/userfiles/216/dessler09b.pdf
A31D-0134. Trajectory Calculations of Hydration/Dehydration in the
Lower Stratosphere from Aura/MLS Water Vapor Measurements. S. Wong;
A. E. Dessler
Abstract:
Hydration/dehydration rates at 365 K isentrope are estimated by
averaging the differences of two Aura MLS H2O measurements closely
linked by two-day Lagrangian trajectories. Stratospheric dehydration
mainly occurs in Northern Hemispheric winter over the tropical western
Pacific, where seasonally averaged rates are collocated with regions
of high deep convective activity and relative humidity (RH). The
Madden-Julian Oscillation (MJO) modulates the tropical dehydration
through the migration of deep convection. The dehydration rate over
the western Pacific is strongest when the enhancement in deep
convection migrates to about 160°E, and dehydration appears over the
Indian Ocean when the convection is enhanced over 80°E. Hydration of
the stratosphere mainly occurs over the summertime subtropical-
extratropical continents. The Asian monsoon provides the strongest
stratospheric hydration during Northern Hemispheric summer. The
hydration rates associated with the Asian monsoon is modulated by the
MJO, becoming larger when the tropical convection is enhanced over the
Indo/Pacific region (120°-160°E), when the Asian monsoon deep
convective activity is also enhanced.
E. S.
-------------------------------------------------------------------------------------
there are papers on the instrument data, though the AGU presentation
might be the first such release.
http://www.nytimes.com/2009/12/16/science/space/16carbon.html
Here's the title of the session presentation:
A41B-0084. Estimates of the water vapor climate feedback during the El
Niño Southern Oscillation. A. E. Dessler; S. Wong
Abstract:
We have estimated the strength of the water vapor feedback by
analyzing the changes in tropospheric specific humidity during El Niño
Southern Oscillation (ENSO) cycles. We do this analysis in climate
models and in two reanalysis products, the European Center for Medium-
Range Weather Forecasts Reanalysis (ERA40) and the NASA Modern Era
Retrospective-analysis for Research and Applications (MERRA). The
water vapor feedback during ENSO in the models ranges from 1.4 to 3.9
W/m^2/K, and in the ERA40 and MERRA it is 3.7 and 4.7 W/m^2/K,
respectively. Taken as a group, these values are higher than previous
estimates of the water vapor feedback in response to century-long
global warming, suggesting that the ENSO water vapor feedback may be
stronger than the water vapor feedback in response to long-term global
warming. We also examine the reason for the large spread in the ENSO-
driven water vapor feedback among the models and between the models
and the reanalyses. We show that the spread is not related to the
variation in the simulation of water vapor, but are due to differing
estimates of extratropical surface temperature variations during ENSO.
The models and the reanalyses show a consistent relationship between
the variations in the tropical surface temperature over an ENSO cycle
and the radiative response to the associated changes in q.
A link was also given to their J. Climate paper:
http://geotest.tamu.edu/userfiles/216/dessler09b.pdf
A31D-0134. Trajectory Calculations of Hydration/Dehydration in the
Lower Stratosphere from Aura/MLS Water Vapor Measurements. S. Wong;
A. E. Dessler
Abstract:
Hydration/dehydration rates at 365 K isentrope are estimated by
averaging the differences of two Aura MLS H2O measurements closely
linked by two-day Lagrangian trajectories. Stratospheric dehydration
mainly occurs in Northern Hemispheric winter over the tropical western
Pacific, where seasonally averaged rates are collocated with regions
of high deep convective activity and relative humidity (RH). The
Madden-Julian Oscillation (MJO) modulates the tropical dehydration
through the migration of deep convection. The dehydration rate over
the western Pacific is strongest when the enhancement in deep
convection migrates to about 160°E, and dehydration appears over the
Indian Ocean when the convection is enhanced over 80°E. Hydration of
the stratosphere mainly occurs over the summertime subtropical-
extratropical continents. The Asian monsoon provides the strongest
stratospheric hydration during Northern Hemispheric summer. The
hydration rates associated with the Asian monsoon is modulated by the
MJO, becoming larger when the tropical convection is enhanced over the
Indo/Pacific region (120°-160°E), when the Asian monsoon deep
convective activity is also enhanced.
E. S.
-------------------------------------------------------------------------------------
Alastair
Dec 21, 2009, 7:17:16 PM12/21/09
to globalchange
Hank, Thanks again for your post. It has made me rethink, and so
improve my model.
Eric,
The name of the author of your papers, Andrew Dessler,keeps appearing.
It appears here
http://www.drroyspencer.com/2009/12/little-feedback-on-climate-feedbacks-in-the-city-by-the-bay/
where Roy Spencer, of Christie and Spencer fame, gave a talk at the
AGU at the invitation of Dessler.
Spencer seems to be arguing along the same lines as Lindzen, but I'll
leave others to decide on that.
There is an interesting talk here,
http://www.agu.org/meetings/fm09/lectures/lecture_videos/A23A.shtml
by Richard Alley from the AGU where he talks about the Faint Young Sun
Paradox, and Snowball Earth.
Cheers, Alastair.
Eric Swanson
Dec 22, 2009, 3:12:16 PM12/22/09
to globalchange
I notice that Spencer wants us to accept his analysis using UAH MT
time series.
time series.
Perhaps he has forgotten that the MSU channel 2 data is contaminated
with input from the stratosphere. At the beginning with his first
graph on page 2, he throws in some AMSU data, which, if my memory is
correct, uses different frequencies than the MSU, thus his time series
can not be combined unless he simulates the MSU with the AMSU data. I
suspect that both include the stratospheric contamination.
Spencer is only able to extract his "looping" patterns after heavily
filtering the data. But, his monthly running 3 month running mean
induces a time lag and a running mean will also exhibit aliasing in
the filtered time series. One might expect that the natural filtering
effect of the thermal mass of the oceans would also induce a lag in
the "temperature" data, so looking only at a single year's "event" he
points to on page 4 may be just be part of the internal ENSO process
we know and love. I don't see why he would expect to find a
meaningful indication of the cloud feedback, given the short filtering
period and the long lag of the circulating oceans.
Spencer points to a period of cooler conditions after Mt. Pinatubo
erupted for the graph on page 5. Really? What a surprise. Here, he
uses a different filter, based on 72 day "seasons" not the 3 month
running mean. Perhaps he hasn't noticed that nature doesn't work with
mankind's arbitrary division of the year into "months" and 72 days is
even stranger, unless that is a value which gives an answer he wants
to see. I would think that a better analysis would start by averaging
all the days in each season, then apply a decent filtering algorithm.
More to the point, why isn't he using yearly averages, an approach
which would filter out much of the noise. Or, would that kill his
conclusion?
E. S.
----------------------------
On Dec 21, 7:17 pm, Alastair <a...@abmcdonald.freeserve.co.uk> wrote:
> Eric,
>
> The name of the author of your papers, Andrew Dessler,keeps appearing.
> It appears here
http://www.drroyspencer.com/2009/12/little-feedback-on-climate-feedba...
> where Roy Spencer, of Christie and Spencer fame, gave a talk at the
> AGU at the invitation of Dessler.
> Spencer seems to be arguing along the same lines as Lindzen, but I'll
> leave others to decide on that.
[cut]
> Cheers, Alastair.
Tom Adams
Jan 2, 2010, 8:04:45 AM1/2/10
to globalchange
In his new book, Hansen discussed the fact that Lindzen never
addresses the sensitivity implied by the glacial/interglacial
transitions of the last half million years. He says
Lindzen operates like lawyer who only discusses evidence in favor of
his position. not
like a scientist who seeks a theory consistent with all the evidence.
addresses the sensitivity implied by the glacial/interglacial
transitions of the last half million years. He says
Lindzen operates like lawyer who only discusses evidence in favor of
his position. not
like a scientist who seeks a theory consistent with all the evidence.
Hansen has had a number of opportunities to debate or publicly discuss
this matter with Lindzen, but he apparently never asked Lindzen about
it. He asked Lindzen in private about cancer and smoking recently and
Lindzen responded by pointing out evidence against the link.
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