Tuesday, July 10, 2012

Good Answers

are where you find them.  Andy Lacis provided a long exegesis on Judith Curry's blog about how, in particular Gareth Partridge had gone emeritus, but there was a real gem in there which locks the uncertainty monster into jail

This is where it is important to understand that the natural variability of the climate system represents temperature fluctuations about a zero reference point. Moreover, these random-looking fluctuations most definitely are not random variations (as in random walk), such that given enough time, they could move the global temperature arbitrarily far from its equilibrium reference point. Climate GCMs (and the real world) must conserve energy, so arbitrarily large departures for the equilibrium reference point simply can not happen in the absence of external forcing being applied. Thus, given enough time, the unforced climate will approach its equilibrium point, and averaging over a time scale that is longer than the time scales of the fluctuations will serve to define the point of equilibrium.
Go over there and help the unfortunate in the comments.

30 comments:

TheTracker said...

See also Lacis on why more "skeptic" analysis is published online:

"Why would anyone want stuff that is patently erroneous, irrelevant, or otherwise deficient to be published in the long-established climate science literature?"


More:
http://theidiottracker.blogspot.com/2012/07/quote-of-day-andy-lacis-ftw.html

Anonymous said...

Dr. Lumpus Spookytooth, phd.

@andrew lackis

Andrew, that there is an equilibrium reference point is an opinion, so no the GCMS do not have to conserve energy, you just make them do it.

And since I know I will be getting a smart ass reply, what is the equilbrium reference point, precisely. What is the exact temperature if it even exists at all.

Anonymous said...

Dr. Lumpus Spookytooth, phd.

@thetracker

that's the equivalent of saying Trenberth, Mann, Schmidt and Hansen don't like the papers.

Also, the article Lacis wrote was a complete opinion piece which is becoming more and more expected.

and hey, if anyone thinks we have "a wealth of good climate data"

I know the government has an absolute wealth of good financial data also, so if you believe that

Anonymous said...

Dr. Lumpus Spookytooh, phd.

@Andrew Lackis

"Why does the unforced global annual-mean surface temperature vary? Basically, the climate system does not respond in small enough energy increments as it is approaching energy balance equilibrium. When clouds form, or precipitation takes place, these local attempts toward achieving energy balance, overshoot the global equilibrium point, leading to new corrective attempts toward energy balance."

Basically, this is one of the most unscientific opinion pieces I have ever read, yet again! Mr. Lackis, the clouds are not acting and reacting around some made up equilbrium point, if so, what is it? I want the precise temperature. There aren't new, corrective attempts toward energy balance, that's another opinion.

Anonymous said...

"Thus, given enough time, the unforced climate will approach its equilibrium point, and averaging over a time scale that is longer than the time scales of the fluctuations will serve to define the point of equilibrium."

The "unforced" climate of Mars has had 4.5 billion years to equilibrate, yet has warmed 4 times faster than Earth over the past 20 years.

Anonymous said...

@ Lumpus

What Lacis means is that you can't pretend that C20th climate behaviour is the result of random variation. The trend is too apparent - conservation of energy would be violated by more than a modest wibbling around quasi-equilibrium. You don't need to know exactly where the quasi-equilibrium is. The long term trend (if one exists) reveals a change in forcing.

And lo, and behold.

BBD

Anonymous said...

@ Lumpus

The "unforced" climate of Mars has had 4.5 billion years to equilibrate, yet has warmed 4 times faster than Earth over the past 20 years.

Misrepresentation. Fenton (2007) does not demonstrate 'global warming on Mars'. Read all about it here and delete from your repertoire of self-serving misrepresentations.

BBD

raypierre said...

A slightly more mathematical way of putting it is that in the absence of trends in forcing, the temperature is not brownian motion (random walk) but something more like an AR(1) process, with a tendency for the state to relax back to an equilibrium with a certain time constant. What's more, that time constant is proportional to the climate sensitivity, so if somebody is arguing for large natural fluctuations, they are simultaneously arguing for high climate sensitivity. It's all a consequence of the key role of top-of-atmosphere energy balance.

Of course, the linear AR(1) process is not a good quantitative fit to the real climate system, since one has multiple time scales of ocean heat uptake, plus various nonlinearities. But it does serve to connect the natural variability issue with the climate sensitivity issue

Brian Dodge said...

Dr. Lumpus Spookytoot - the gummint does have a wealth of good financial data. The problem is the economists and politicians don't understand the difference between science and wishful thinking, or reality and belief, and consequently THEIR models are crap. The value of a
Collateralized Debt Obligation is a fictive value created by people; the number of joules required to melt a gigaton of Greenland ice is a number which is the same every time someone measures it.
Members of the political class who believe they "make their own reality" are incapable of understanding "equilibrium reference point" and "conservation of energy". They really think, like Dr. Spookytooth, that science is just a matter of opinion, that an evil cabal of climatologists that "just make [climate models] do it"(show global warming), and that there is no difference between the flow of energy in the climate and the flow of lies from their mouth.

Anonymous said...

The literature does in fact indicate global warming on Mars due to albedo changes, at a much faster rate than on Earth over the past 20 years.

It is unknown why the albedo of Mars has decreased, just as it is unknown why both ISCCP and Earthshine data indicate there was a significant decrease in Earth's albedo from the mid 1980's to late 1990's in concert with global warming. To assume man-made CO2 is the only possible cause without understanding cloud/albedo behavior, ocean oscillations, etc, etc is misrepresentation and junk science.

Anonymous said...

@ Anonymous

Stop repeating contrarian nonsense and read the link. The higher albedo in 1977 was the aftermath of a planetary dust storm.

BBD

Anonymous said...

Anonymouse should know that Mars albedo changes have well known causes - dust storms since that is about all the weather Mars has.

Anonymous should also know that ISCCP gives no significant long term albedo change, see http://isccp.giss.nasa.gov/zFD/an9090_ALB_toa.gif

Rib Smokin' Bunny

Anonymous said...

Once again, BBD ignores that albedo is not acting and reacting around some fictitious equilibrium point. Both ISCCP and Earthshine data indicate there was a significant decrease in Earth's albedo from the mid 1980's to late 1990's in concert with global warming. To assume man-made CO2 is the only possible cause without understanding cloud/albedo behavior, ocean oscillations, etc, etc is misrepresentation and junk science.

Rib Smokin' Bunny:
In fact the ISCCP graph you linked does show a 2+% declining trend in albedo from ~1983 to 2000. A 2% decline in albedo results in far more forcing than alleged from CO2. Earthshine data is similar.

Anonymous said...

@ anonymous

I don't think the ISCCP data are reliable enough for you to claim anything very much. The mainstream scientific position on radiative forcing by CO2 isn't 'misrepresentation and junk science' except in the minds of 'sceptics'. Who are invariably unqualified to make such an assertion and manifestly biased.

Evan et al. (2007):

The International Satellite Cloud Climatology Project (ISCCP) multi-decadal record of cloudiness exhibits a well-known global decrease in cloud amounts. This downward trend has recently been used to suggest widespread increases in surface solar heating, decreases in planetary albedo, and deficiencies in global climate models. Here we show that trends observed in the ISCCP data are satellite viewing geometry artifacts and are not related to physical changes in the atmosphere. Our results suggest that in its current form, the ISCCP data may not be appropriate for certain long-term global studies, especially those focused on trends.

Campbell (2004)

The International Satellite Cloud Climatology Project cloud analysis has a small view angle dependence in its cloud estimate. There is about 10% more cloudiness reported at 60 degree view angle compared to normal views of the same scene. Over the twenty year ISCCP record, more geosynchronous satellites have been added to the analysis and the mean view angle over the globe has become more vertical. This systematic change in view point convolved with the view angle dependence in cloudiness produces much of the decreasing trend in ISCCP cloud amount, both regionally and globally. An empirical correction can be made to the ISCCP cloudiness time series which makes the data more useful for climate studies. This angular dependence is a real physical phenomena much like bi-directional reflectance for reflected sunlight from different surfaces. It should be incorporated in the conversion of instantaneous cloudiness at a particular view angle to averages over time and over view angle. Finally we discuss the impact on optical depth and radiative transfer in cloud fields.

BBD

a_ray_in_dilbert_space said...

Wow Anonymous@2:37,
You must be on some very, very good drugs to get a 2% decrease in albedo out of that plot!

Is there anyone there who could maybe teach you to read a graph?

dbostrom said...

Why is it "Dr." and "PhD?"

Dr. PhD of what? Divinity and hospitality science?

Anonymous said...

BBD

Thanks for the "arguments against" paper

1. Apparently ISCCP doesn't think too highly about the "arguments against" in this 2007 paper since they haven't adjusted their data accordingly

2. The "unadjusted" ISCCP data shows ~15% decline in cloud amount from ~1987 to 2000 and an "adjusted" decline per this paper of ~2% over the same period.

3. Even after these adjustments, the forcing from a 2% decline in cloud amount far exceeds that alleged to be due to man-made CO2

4. You haven't addressed the fact that Earthshine data also shows a significant decrease in albedo from ~1985-1997.

raypierre said...

Anonymous, you haven't been following the literature. The 2004 Palle paper was an honest, but oversold and deeply flawed attempt. The Earthshine group has been working hard to winkle out errors and inconsistencies, and the satellite people have been doing the same. But the upshot is that it is very hard to accurately measure small trends in albedo over the satellite era, and there is no credible reason to posit a long term albedo fluctuation at present, though albedo changes due to volcanic eruptions are quite clear. Background, with citations to peer-reviewed literature can be found at

http://www.skepticalscience.com/earth-albedo-effect.htm

Note also that if a downward albedo trend is ultimately detected, that doesn't by itself mean that the albedo change is the root cause of climate change. Climate models with high climate sensitivity are generally sensitive because they dissipate low clouds as climate gets warmer, leading to a positive cloud feedback. So, if an albedo reduction is detected, one needs to ask the question of whether this is evidence for high climate sensitivity due to positive cloud feedback. Many people are trying to address that question, but it's nearly impossible from the past record, though it may become possible over the next 20 years if we have a suitable earth radiation budget monitoring platform.

But this whole cloud albedo discussion is off-topic. I don't see what it has to do with Andy Lacis' pithy summary of why climate isn't a random walk. You'd have to believe that clouds were capable of spontaneous magical and persistent large scale re-organization independen of any changes in external forcing or the ocean state for this to impinge on Andy's point, and nobody but Roy Spencer believes that.

dhogaza said...

"Dr. PhD of what? Divinity and hospitality science?"

Naw, PhD of sockpuppeting Dr. [NOT] Jay Cadbury, PhD [NOT]

Anonymous said...

Anonymouse showing significant statistical ignorance:" show a 2+% declining trend"

made up number and no error bars = FAIL.

Rib Smokin' Bunny

dbostrom said...

While Dr. Dr. Dr. Dr. PhD is dormant in his refractory period take a moment to catch up on the latest doings by ATI. They're going after Katherine Hayhoe and Andrew Dessler, with a new twist:

American Tradition Institute seeks the release of emails with journalists to find details that could be used to discredit science

Does that make you mad? Why not get even, too?

If 1000 warmista climate blog enthusiasts each are angry enough to contribute $10 to the Climate Science Defense Fund then CSDF will raise $10,000, enough to inject some serious glue in ATI's treads. This should happen every time ATI makes a move like this.

I'm $250 mad. How enraged does ATI make you? $5? $10? More?

Anonymous said...

Random Walks
-- by Horatio Algeranon

Random walks
Like random talks
Are difficult to follow

Measureless motion
Like poisonous potion
Is difficult to swallow

Dallas said...

raypierre said, "A slightly more mathematical way of putting it is that in the absence of trends in forcing, the temperature is not brownian motion (random walk) but something more like an AR(1) process, with a tendency for the state to relax back to an equilibrium with a certain time constant. "

Very true. That is why the 1995 situation with reduced stratospheric cooling and the SST approach to a more stable plateau instead of the continued rise are interesting.

http://i122.photobucket.com/albums/o252/captdallas2/climate%20stuff/whatsnormal.png

That is converted into Wm-2 because I have been looking at the average SST of about 284.25K around 425Wm-2 and looking at an ocean energy balance. That does look like and approach with an overshoot and decay.

Anonymous said...

Dallas thinks something raypierre said supports this:"That is why the 1995 situation with reduced stratospheric cooling and the SST approach to a more stable plateau instead of the continued rise are interesting."

There ain't no stable plateau, just noise (from climate variability) superimposed on a trend. Note the "plateau" in 1900 at -0.3 from the 1960-1990 average, the "plateau" from 1950-1975 at the 1960-1990 average, etc.

Take a line, add random noise and you will see "plateaus" galore that mean absolutely nothing.

Rib Smokin' Bunny

raypierre said...

Rib, there's noise and there's noise. Adding AR(1) noise to a trend will give you different statistics of plateaus than adding brownian motion.

Dallas said...

Rib, sometimes the noise is the signal :) Depending on the recharge time constants of the various ocean thermal layers there are likely several plateaus. The SST would just be an indication of one or two, or.. just "noise". The shape of the curve may be circumstantial evidence, but enough of that will still get a conviction.

Anonymous said...

Random Walks (part II)
-- by Horatio Algeranon


ARy traipses
On airy mesas
Will put you on your butte

But random spills
Down random hills
Will ruin your new suit

raypierre said...

With AR(1) I had just begun
With AR(2) it was still brand new
I use AR(3) for rings of a tree
And AR(4) for much, much more
Then with AR(5) I was really alive
But that AR(6), it's just clever as clever
I think I'll use AR(6) forever and ever

John Mashey said...

Oh my, if there's anything I never expected to see, it's Horatio inciting raypierre into dueling with AR verses.

People may recall DC's post, which included some discussion of AR(1) processes with odd parameters.

David Ritson tried to get Ed Wegman's version of that code, to no avail, so asked Rep. Henry Waxman for help. See this for new information on that. Maybe we'll finally get to see the code promised long ago.

Bart said...

Raypierre,

You wrote that, after an unforced change in climate state, there is

"a tendency for the state to relax back to an equilibrium with a certain time constant. What's more, that time constant is proportional to the climate sensitivity"

Intuitively it makes sense that if a random change can push the system far away from its equilibrium, it must mean the system is very sensitive to any changes in state (whether forced or unforced), but I don't quite grasp the explanation you gave that the timescale of equilibration is proportional to climate sensitivity. Could you elaborate?

Bart