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tomclarke
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Post by tomclarke »

Politicianspeak jargon.

Actually, it refers to a different issue - but I don't much like it. It does not mean much as it is used.

IntLibber
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Post by IntLibber »

MSimon wrote:
tomclarke wrote:MSIMON!

rail to rail only if loop gain is >1. the real situation corresponds to loop gain < 1 so the feedback amplifies the original but the output remains linearly (in this approximation) dependent on forcing input.

The circuit is nice because with gh/gf < 1 you can see exactly how the amplification works.
What is this tipping point re: climate I keep hearing so much about?
The disasturbationists make the false assumption that water vapor is a positive feedback in every and all circumstances to such a degree that ever 1 degree of CO2 warming causes 4 deg of water vapor caused warming. This obviously ignores several problems with this blanket statement:

a) such an increase in water vapor in the winter obviously means more snow and ice precipitation, which increases earth's albedo and thus leads to cooling.
b) daytime cloud formation causes cooling from albedo increase

It is really only night time clouds in high latitudes that causes warming from water vapor.

Anyways, back to the 'tipping point': the claim is that the 4 C increase from water vapor will cause an increase in natural CO2 emissions from tundra and the oceans, which will cause more water vapor related warming, ad nauseum until suddenly we are all living on Venus.

Obviously, if Earth's climate were so unstable and sensitive to CO2 variation, then past periods when CO2 levels exceeded 1000 pmm or even 1500 ppm or more should have triggered such a runaway greenhouse effect, but did not.

tomclarke
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Post by tomclarke »

the 'polyannbationists' on this thread have two classes of argument: one I am quite sympathetic with, the other is feeble.

The climate system is incredibly complex. If we make assumptions about human behaviour it is mostly physical - with bits of biology added to uncerstand the carbon/solil cycle and the affect of vegetation on albedo etc. But still incredibly complex.

So the idea that GCMs may be flawed because they do not take sufficient account of all the variables has at least some substance. They can never be perfectly accurate - it is a matter of accurately estimating the inaccuracy!

Posts like intlibbers which from an armchair with the help of simplistic arguments no doubt recycled from a few blogs or newspaper articles trivialise the situation in a way which helps no-one. if the climate is complex, you will not sort it out with a few sound-bites. If you have serious arguments go raise them sriously - A literature survey would allow you to put them into context and read the careful quantitative analysis which they merit, and under which they do not look convincing.

If on the other hand the purpose of this debate is to confirm readers preconceptions - perhaps intlibber's post is right on the spot!

Best wishes, Tom

PS - and let's stop using collective nouns which imply solitary sexual practices? I will if you do.

IntLibber
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Post by IntLibber »

tomclarke wrote:the 'polyannbationists' on this thread have two classes of argument: one I am quite sympathetic with, the other is feeble.

The climate system is incredibly complex. If we make assumptions about human behaviour it is mostly physical - with bits of biology added to uncerstand the carbon/solil cycle and the affect of vegetation on albedo etc. But still incredibly complex.

So the idea that GCMs may be flawed because they do not take sufficient account of all the variables has at least some substance. They can never be perfectly accurate - it is a matter of accurately estimating the inaccuracy!

Posts like intlibbers which from an armchair with the help of simplistic arguments no doubt recycled from a few blogs or newspaper articles trivialise the situation in a way which helps no-one. if the climate is complex, you will not sort it out with a few sound-bites. If you have serious arguments go raise them sriously - A literature survey would allow you to put them into context and read the careful quantitative analysis which they merit, and under which they do not look convincing.

If on the other hand the purpose of this debate is to confirm readers preconceptions - perhaps intlibber's post is right on the spot!

Best wishes, Tom

PS - and let's stop using collective nouns which imply solitary sexual practices? I will if you do.
The term disasturbationist is a term coined 15 years ago on the transhumanists email lists to describe the growing millenialism of the religious right and greenie left.

I've read the literature and its critics, my own cousin is a doctor of climatology, btw, and I am very well grounded in my position here. Most professional climatologists actually believe AGW is BS and feel the AGW disaster folks are an embarassment, akin to Erich von Daniken's relationship to real archaeologists, or astrology to astronomy.

tomclarke
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Post by tomclarke »

Intlibber -

Thanks for the history of "disasterbationist". It is a clever (if unpleasant) word.

I am interested in this claim of yours about "most climatologists". There is an active scientific literature on GCM.

The IPCC review all this stuff and find that of the credible (=> detailed, run for enough years to have the obvious problems sorted out, etc) models nearly all predict sensitivity to CO2 of 2.5 to 4 degrees per doubling.

This figure is the scientific basis for AGW - since the fact that our activities have increased CO2 and will continue to do so is indisputable.

Now - do these contrarian climatologists adopt the stance that climate is too complex, and the models do not work? Do they quantify the reasons for innacuracy and argue their case for wider error bars in the scientific literature? This is a respectable endevour and will get published if the case is presented in detail enough to be believable.

Do they set up their own models which predict differently - in which case the interesting debate is the scientific arguments about the different assumptions of these models and the "normal" ones.

If any of these things happen you could direct seekers of the truth like me to the relevant work.

Otherwise, given the (obvious to anyone studying the field) complexity of the whole endeavour, why should prejudices be weighed higher than the very large body of scientific literature on GCMs?

I am not crediting scientists with greater wisdom thean others - it is just that published papers can be refuted, supported, etc. This process, done seriously, can sort out the wheat from the chaff.

Best wishes, Tom

tomclarke
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Post by tomclarke »

intlibber wrote:Anyways, back to the 'tipping point': the claim is that the 4 C increase from water vapor will cause an increase in natural CO2 emissions from tundra and the oceans, which will cause more water vapor related warming, ad nauseum until suddenly we are all living on Venus.

Obviously, if Earth's climate were so unstable and sensitive to CO2 variation, then past periods when CO2 levels exceeded 1000 pmm or even 1500 ppm or more should have triggered such a runaway greenhouse effect, but did not.
I think the "tipping point" issue is a red herring - something coined to make probabilities more real to politicians, so I do not try to justify it.

The issue is more subtle than you represent here. There are many possible positive feedbacks - and perhaps also negative feedbacks. Once we depart from the recent historic record we have no way of knowing what these will be since at other times when CO2 was as high as it is now (millions of years ago) many other features of the climate were different - for example a cooler sun.

So it is just that 4 degrees long term is a very large perturbation and WE DONT KNOW what will be the consequences. If we look at history we can see that the normal condition is for temperature on earth to be quite unstable - so this does not bode well.

Nothing magical about 4 degrees - of course. Some would argue that 3 degrees or 2 degrees is too large a long-term perturbation.

And arguing that high CO2 did not trigger high temperatures in the past would require as careful as possible consideration of the known other forcing factors, as is done by the GCMs.

The main personal argument against desirability of 4C increase is not so much the runaway catastrophe - which is unknown - but the fact of changes to existing weather patterns - which is known. Our civilisation depends on reliable sources of food etc and even if global output - once we have adjusted to the changes - is as high the adjustment will be painful in the extreme.

For example imagine if N America became inhospitable to large-scale agriculture - the prairies a permanent dust-bowl - etc. The fact that somewhere else, without the relevant infrastructure and politically hostile to the US, becomes more hospitable for large-scale argiculture is not much help.

Is this sort of global upheaval, mass-starvation, and war really not a threat?

It dwarfs all the efforts of Al-Qaeda by a very large factor.

Best wishes, Tom

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Post by MSimon »

And arguing that high CO2 did not trigger high temperatures in the past
If the ice cores are worth anything then CO2 increases follow heating. Which would indicate that the CO2 came from the oceans and is not a significant forcing but a resultant.

Since that equilibrium between the ocean's CO2 content and the atmospheric content is 50 to 1 that is not an unreasonable assumption. Now consider that the recent warming began around 1800 or so.

And of course if the water vapor term is negative rather than positive then even 2 deg may be too high. It may be as little as .6 deg. According to some scientists.

And you know - in science it only takes one. And the number is rather higher than one. It is at least 650 including former IPCC scientists.

I used to be a CO2 warmist. Until I was convinced otherwise by various bits of evidence.

From the geologic record we see two stable states. Glacials and interglacials. We are now in an interglacial. What is the next likely state? Very difficult question. I'm thinking. I'm thinking.

So how is weather predicted? Every 6 hours the models are reset to current conditions. How about climate? In a chaotic system any errors can get multiplied in each succeeding time increment.

And what else do we know about modeling physical systems? If the grid mesh areas are too large the results do not converge. And it is conceded that the grid mesh sizes are too large even by the modelers. GIGO. This is aside from errors in parameters. Initial conditions. etc.

Also note that temperature records are kept in increments of 1 deg F. With accuracies of actual measurements adding another deg or two F of error. And yet results are reported in increments of about .2 deg F. i.e. they are reporting results not justified by instrument accuracy. On top of that the models vary greatly from each other. So which one is correct? Not to worry. They AVERAGE the results to make up for the errors in initial conditions and estimating the values of various parameters. Very scientific no doubt.

So why not just reduce mesh size and agree on the various parameters and see if the models agree? Well it turns out THERE IS NO CONSENSUS. And there is not enough computing power to get the mesh size required.

And how much change in albedo would be required to offset CO2 assumptions? Less than 1%. And guess what albedo is not known to that accuracy on the time scales required. GIGO.
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MSimon
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Post by MSimon »

So what do us electronicers do when we know the bounds of accuracy of various parameters in a model?

One thing we do is corner analysis and another is 10,000 Monte Carlo runs. I have read a few Climate Model papers and have never seen that sort of thing mentioned. But maybe I missed it.

And since the models are sequential then an error in a series of years are propagated to the end. Given that the last eight or ten years of stagnant or cooling temps was not predicted that would tend to say that the models are giving too high a result. Or that internal variation of the climate systems are wrongly estimated. Or are biased in a direction opposite what the climate models uses. GIGO.

And don't forget the climate is chaotic. As are the models. If the models and reality don't match the model results and reality can be wildly different from each other. Under such conditions averaging doesn't work. Because if model and climate strange attractors are different the models could head high while the climate heads low.

Fortunately the models used to be good enough to fool the rubes. Unfortunately the marks are wising up. Fortunately it seems the geniuses in Congress are the last to know. Unfortunately the Congress critters can be bought off by the alligator shoes guys. So they are giving out tons of CO2 chits for free.

We do know that cap and trade do not work to lower CO2 emissions. They do help raise energy prices significantly though.

And you know what? With China and India growing like crazy and increasing CO2 output, estimates are that they will account for 2X the CO2 output of this year's developed world by around 2030.
Engineering is the art of making what you want from what you can get at a profit.

tomclarke
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Post by tomclarke »

Simon,

I will ignore the scattergun OT approach of your reply and deal with the relevant points:
You think GCMs underestimate errors? Fine, engage properly with the debate and write a paper about it. My point is tehre enough people who believe you and spend their time writing anti-AGW papers. maybe you could persuade one of them to follow your idea up? then we will get a proper scientific debate.

You think the recent 10 years of global temperatures are outside the expected natural variation from the GCM predictions? The detailed discussion of this I have seen does not bear this out. This is quite a straightforward claim - you can publish it, or point to somone else who has done this, and we will see what the subsequent trail of argument and counter-argument looks like.

You think nonlinear issues in the climate system could force it low? Equally they could force it high? Either way the existance of a global averaged offset of 4C is significant 4C is higher than any normally seen chaotic variation when averaged over 20 year timescale.

If the point of your post is you can't predict climate from a 10 year time series then I agree! Oh dear - there perish about 50% of the (flawed) anti-AGW papers....

tomclarke
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Post by tomclarke »

If the ice cores are worth anything then CO2 increases follow heating. Which would indicate that the CO2 came from the oceans and is not a significant forcing but a resultant.
That is why you need sophisticated climate models to go through the prehistoric data and disentangle effects. Everyone (bar a few on the lunatic anti-AGW fringe) agrees that there are linked effects:

(1) more CO2 => higher atmosphere temp (fast)
(2) oceans heat up (timescale probably 100 years or so)
(3) hotter oceans => CO2 emitted from oceans


That, as you well know, is not the point save that it indicates one very long-term positive feedback. There are many other long-term feedbacks - e.g. maybe more CO2 increases vegetation growth (I've no idea what the current knowledge about this is, or what it does) so disambiguating these is difficult.

Best wishes, Tom

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Post by tomclarke »

The current science indicates 2.5-4 C as reasonable error bars for sensitivity, but there are outliers. These models get better, criticise and influence each other, assumptions are cross-validated and become more or less accepted. This whole process, and the fact that the respectable models have a very significant variation, means that the results change and get more accurate as time goes on. So if Simon is right the science will correct itself. But I am afraid (I would like him to be right) the chances of this are small.

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Post by TallDave »

tomclarke wrote:The current science indicates 2.5-4 C as reasonable error bars for sensitivity, but there are outliers. These models get better, criticise and influence each other, assumptions are cross-validated and become more or less accepted. This whole process, and the fact that the respectable models have a very significant variation, means that the results change and get more accurate as time goes on. So if Simon is right the science will correct itself. But I am afraid (I would like him to be right) the chances of this are small.
Ptolemaic models kept getting better and more accurate too. But they were all wrong. And that was a very predictable system, unlike climate.

Ptolemaic models anthropocentrically assumed the Earth was the center. GCMs all start with the same flawed anthropocentric assumption that trace amounts of CO2 produced by huimans are driving climate change, an assumption for which there is scant evidence but lots of environmentalist enthusiasm.

At present, no GCM has predicted climate better than the naive forecast.
You think GCMs underestimate errors? Fine, engage properly with the debate and write a paper about it. My
Forecasting scientists already have. They say there is no scientific basis for the IPCC predictions.

The reliability being assigned to GCMs is a species of religious faith, complete with prophecies of doom, bearded prophets, and sacrifices.

Even in the unproven case that we experience significant warming between now and 2100, the net consequences from global warming are likely to be positive, as they have been throughout human history. Far more people are hurt by excess cold than by excess heat. To combat this inconvenient truth, we get lots and lots of "impact studies" that either only look at the negatives or say "something bad might happen."

Environmentalists just don't want to face their own inconvenient truth: the environment has gotten far better over the past few decades, and their movement's purpose has lost its urgency.

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Cooking the books

Post by MSimon »

Climate "science" cooking the books:
...if there is one scientist who knows more about sea levels than anyone else in the world it is the Swedish geologist and physicist Nils-Axel Mörner, formerly chairman of the INQUA International Commission on Sea Level Change. And the uncompromising verdict of Dr Mörner, who for 35 years has been using every known scientific method to study sea levels all over the globe, is that all this talk about the sea rising is nothing but a colossal scare story.

Despite fluctuations down as well as up, "the sea is not rising," he says. "It hasn't risen in 50 years." If there is any rise this century it will "not be more than 10cm (four inches), with an uncertainty of plus or minus 10cm". And quite apart from examining the hard evidence, he says, the elementary laws of physics (latent heat needed to melt ice) tell us that the apocalypse conjured up by Al Gore and Co could not possibly come about.

The reason why Dr Mörner, formerly a Stockholm professor, is so certain that these claims about sea level rise are 100 per cent wrong is that they are all based on computer model predictions, whereas his findings are based on "going into the field to observe what is actually happening in the real world".
One of his most shocking discoveries was why the IPCC has been able to show sea levels rising by 2.3mm a year. Until 2003, even its own satellite-based evidence showed no upward trend. But suddenly the graph tilted upwards because the IPCC's favoured experts had drawn on the finding of a single tide-gauge in Hong Kong harbour showing a 2.3mm rise. The entire global sea-level projection was then adjusted upwards by a "corrective factor" of 2.3mm, because, as the IPCC scientists admitted, they "needed to show a trend".

When I spoke to Dr Mörner last week, he expressed his continuing dismay at how the IPCC has fed the scare on this crucial issue. When asked to act as an "expert reviewer" on the IPCC's last two reports, he was "astonished to find that not one of their 22 contributing authors on sea levels was a sea level specialist: not one". Yet the results of all this "deliberate ignorance" and reliance on rigged computer models have become the most powerful single driver of the entire warmist hysteria.


http://www.climatechangefraud.com/conte ... /3623/236/

And even at 2.3 mm a year that amounts to .23 m in a century. Nine inches.

Now given all that and the fact that the huge funding flows depend on predictions of catastrophe is it possible (likely) that the IPCC is cooking the books in other climate "science" areas? Hockey stick anyone? Well the hockey stick paper passed peer review. And yet the IPCC featured the paper prominently and several times after it had been shown to be the result of the modeling method and not a result of the data. And what do we know? Mann and his cohorts refused to release everything required to check his methods for years. A policy he continues to adhere to. Delay, delay, delay.

And the same refusals to release data and methods on the part of a number of IPCC featured scientists continues to this day.

If the IPCC was a commercial venture some Attorney General would be investigating them for fraud.

Here is another way to look at the results. Suppose each calculation is in error by .01% (due to ill chosen factors, computer limitations, data errors etc.). The models do calculations on 15 minute intervals (i.e. the climate is time sliced into segments of 15 minutes). That is some 34,000 time segments to make up a year. What would be the expected errors from just a year equivalent of calculations? Around 97%. How about a century?

OK. Suppose the modelers are much more accurate than that. Suppose they are .99999999 accurate on a given calculation (including assumptions). They are then 99.997% accurate after one year. After 100 years they would be 96.6% accurate. Which only puts them off 10 deg K after a 100 years equivalent of climate time. And yet the modelers quote us numbers like 3K warmer. Or 5K warmer. Or 10K warmer. With very small error bands. And that error (10K) assumes that they got things right to 1 part in 100,000,000. What are the odds?

They should do better if the feedback is negative. But still. If the assumptions are wrong (guaranteed) the errors will propagate. Just to keep the round off errors from propagating they have to use mantissas on the order of 40 or 50 bits.

A look at error propagation in IIR and FIR filters (which is what a climate model is in essence) would be instructive. If the models are done as IIR filters it is very very bad. If they are done as FIR (phase linear) filters it is only bad. And you know what? I'm betting on IIR (feedback) filters.

And out of this pile we are expected to bet the lives of billions and hundreds of trillions of dollars? Fortunately the Chinese and Indians are not buying it. I wonder what my name sounds like in Chinese?

I'd really like to see the corner cases for the climate instead of one magic number. I'd like to see Monte Carlo runs. For both the sceptic and believer assumptions of all the parameters. My guess? None of the cases would look very good and none of them would be any better at predicting the future than coin tosses. And some would be a lot worse.
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tomclarke
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Post by tomclarke »

OK - once more unto the breech etc etc

G&A The paper is written from the perspective of stochastic forecasting. As we have argued here before GCMs would be unsound if stochastic forecasts. In fact GCMs are not even design to forecast - though the same (or similar) models can be used to make regional forecasts. They don't do it very well because medium-term climate forecasting is not easy. It is also easy to pick holes in the paper - they read the IPCC AR4 selectively (only one Chapter) ignoring the rest of teh report, so their conclusions about IPCC are based on a thorough misunderstanding of what it does.

As you all know GCMs are physical models, and designed to determine a physical parameter - the sensitivity of the climate to CO2 increase.

As an example of the tendentious nature of these arguments about forecasting, and how it is so easy for bad statistics to be recycled on blogs:

Suppose there is a stochastic time series mean 0 variance 1 one sample per year.

(SBS1) If you look back over the last 20 years and pick the highest point on this sequence, then consider trends from this point to the future - I will naturally observe a downwards trend. This is illusory, caused only by the the selected starting point.

[Skeptic bad science strategy no 1]

(SBS2) If I now take the average of this sequence over a large number of years I get close to 0. If I use as a forecast a null hypothesis, constant, equal to this average, the RMS error of the forecast will tend to 1 (the standard deviation of the original sequence).

If on the other hand I model the sequence stochastically as mean 0, variance 1 and look at the RMS error of my model versus the original what happens? Oh dear, the error is 2^(1/2) - 40% larger than the null hypothesis. therefore the model (as a forecast) is obviously broken.
[Skeptic bad science strategy no 2]


(SBS3) Suppose I am modelling the motion of a tennis ball through the air. I use Newton's laws (good enough!). The problem is more complex because of drag from the air. Unfortunately the air around the tennis ball has turbulent flow and is very diffiult to model precidely. There is idealised theory which says that drag should be proportional to the cube of the velocity, or the square of the velocity, depending on the nature of the air flow around the ball. The modellers know this, look at the trajectory of many tennis balls (in different parts of the world, at different times). They develop an equation for the drag of the form D = alpha v^2 + beta v^3. Parameters alpha and beta are determined from the empirical data. The equation is cross-validated, and compared with other equations, using different data.

Clearly, this whole process is suspect - the model is stochastic and the final predictions of tennis ball movement depend on the (bad quality) data used to set the parameters alpha and beta.
[Skeptic bad science strategy no 3]

I'll use the abbreviations as necessary bin future replies.

Simon has repeatedly followed SBS3
G&A SBS1
Simon's statement that cooling over last 10 years => AGW broken is a version of SBS2 (modified by the fact that individual samples are not independent)

A little question:
Why do so many of the trends quoted as evidence on this site start from 1998 (i.e. consider the last 10 years)?
[Hint - consider SBS1]


(SBS4) Morner & sea level rise:
An independent check of the evidence will show that Morner's comments are not what everyone else thinks. Specifically:
http://en.wikipedia.org/wiki/File:Recen ... l_Rise.png

Perhaps all 24 of these PSMSL logs have been contaminated by mad GCM enthusiasts pumping salt water under underground caverns?

A good example of SBS4 - Find a comment made by one rogue individual. Take it out of context, without checking, and argue from it that IPCC are incompetent/rogues/etc
[SBS4 - believe an outlier without checking]
Simon wrote: I'd really like to see the corner cases for the climate instead of one magic number.
Go read IPCC AR4
Simon wrote: I'd like to see Monte Carlo runs.


Obviously, you have a secret ambition to be come a GCM modeller. All GCMs are tested by doing multiple (Monte Carlo) runs.

Try googling IPCC Monte Carlo and see what you get:
"..... A one-million point Monte Carlo simulation was performed to derive the PDFs (Boucher and ..."

and many others.

Best wishes, Tom

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Post by tomclarke »

Re Morner - SBS4 -

Don't take my word for it. Look at the citations of his paper. Here is the first one I found:

Comment on “Estimating future sea level change from past records”
by Nils-Axel Mörner
R.S. Nerem a,b,⁎, A. Cazenave c, D.P. Chambers d, L.L. Fu e,
E.W. Leuliette a, G.T. Mitchum f
a Colorado Center for Astrodynamics Research, University of Colorado, United States
b Cooperative Institute for Research in Environmental Sciences, University of Colorado, United States
c Laboratoire d3Etudes en Géophysique et Océanographie Spatiales, LEGOS-CNES, Toulouse, France
d Center for Space Research, University of Texas at Austin, United States
e Jet Propulsion Laboratory, California Institute of Technology, United States
f College of Marine Science, University of South Florida, United States
Received 14 July 2006; accepted 25 August 2006
Available online 15 November 2006



We feel compelled to respond to the recent article by
Mörner (2004) because he makes several major errors in
his analysis, and as a result completely misinterprets the
record of sea level change from the TOPEX/Poseidon
(T/P) satellite altimeter mission. One major criticism we
have with the paper is that Mörner does not include a
single reference to any altimeter study, all of which
refute his claim that there is no apparent change in
global mean sea level (GMSL) [see Cazenave and
Nerem, (2004) for a summary]. The consensus of all
other researchers looking at the T/P and Jason data is
that GMSL has been rising at a rate of 3.0 mm/year
(Fig. 1) over the last 13 years (3.3 mm/year when
corrected for the effects of glacial isostatic adjustment
(Tamisiea et al., 2005)).
Mörner gives no details for the source of the data or
processing strategy he used to produce Fig. 2, other than
to say it is based on “raw data”. Because the details of
the analysis are not presented in his paper, we are left to
speculate on how this result could have been obtained,
based on our years of experience as members of the T/P
and Jason-1 Science Working Team. Mörner was apparently
oblivious to the corrections that must be made
to the “raw” altimeter data in order to make correct use
of the data. [.... rest of article follows ...]

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