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The Null Hypothesis Says it Natural
(Part of the How to Talk to a Climate Sceptic guide)
This article has moved to ScienceBlogs
It has also been updated and this page is still here only to preserve the original comment thread. Please visit A Few Things Ill Considered there. You may also like to view Painting With Water, Coby Beck's original fine art photography.Labels: Sceptic Guide
posted by coby @ 3/13/2006 08:55:00 PM
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35 Comments:
At March 14, 2006 1:28 PM,
Anonymous said…
Peter, I think when all of your arguments arguments are refuted by seemingly logical arguments, you re-examine your underlying assumptions to make sure you're on the right track. As Davy Crockett once said "Be always sure you are right, then go ahead."
nanny_govt_sucks
At March 14, 2006 2:25 PM,
coby said…
Hi Peter,
I understand your frustration, as there are many (oh, hello nanny_govt_sucks) who will never accept facts, logic and data. But I find that you should just avoid the inevitable attempts to drag down the level of discourse, present the facts and the logic and don't really expect any capitulation. In the end, the dialogue is mostly for the lurkers anyway.
At March 14, 2006 2:30 PM,
Anonymous said…
Here's another objection for you to work on Coby. Should be no problem, Russian scientist blames GW on the Tunguska Event! Fresh article from today.
http://www.innovations-report.de/html/berichte/umwelt_naturschutz/bericht-56600.html
good luck
sincerely,
Poncedeleon aka Doug L.
At March 14, 2006 2:41 PM,
coby said…
LOL! Thanks, I'll put that in the Crackpottery list and get to it later.
At March 14, 2006 2:57 PM,
Anonymous said…
thresholds for accepting or rejecting a null hypothesis aren't arbitrary. some folks are taught to pick a 90% confidence or a 95% confidence out of hand, but these really don't mean anything.
what needs to be done to make the choice proper is to formulate the problem as a statistical decision, considering the costs of falsely rejecting the null hypothesis and of falsely accepting it in addition to the inherent distributions of the threshold. if the long term costs of doing nothing are huge given that warming were real, one wants to be extra sensitive to detecting warming, even if it proves to be a false alarm. conversely, if the costs of preparing for warming are enormous given that there is none, that should be considered as well.
there's nothing magic about this. we all need to decide what risks do we consider worse. do we fail to prepare for the reality of warming and, then if it proves so, have to pay to repair the equivalent of ten New Orleans a year, thinking we might get lucky? or do we do some mitigation which will be expensive hoping it'll prove to be unnecessary or, if it is necessary, it'll buy us some insurance?
for more about these kinds of statistical choices, see the nice monograph H C Kraemer, S Thiemann, How many subjects?, 1987, ISBN 0-8039-2949-8.
At March 14, 2006 5:10 PM,
Anonymous said…
"I understand your frustration, as there are many (oh, hello nanny_govt_sucks) who will never accept facts, logic and data."
An ad-hom attack from the webmaster? Well, well. How quickly your new blog descends to the level of trash.
Care to back up your attack with any substance, or are you just going to let it hang there as an example of what others can expect here?
nanny_govt_sucks
At March 14, 2006 5:20 PM,
Anonymous said…
"Oh, and by the way, we do in fact have compelling evidence."
The IPCC TAR that you link to has charts that show the divergence between global temperatures and CO2 concentrations over the period 1940-1975. If that's your "compelling evidence" then consider me far less than compelled.
nanny_govt_sucks
At March 14, 2006 5:58 PM,
Anonymous said…
Nanny is a well-known troll. Not sure what policy to recommend for your site, Coby, but there are others who simply bane him/it.
At March 14, 2006 6:16 PM,
coby said…
nanny and I have discussed some of this stuff before at Real Climate so I know what to expect. Banning is too heavy handed, I'm not worried about letting the comments speak for themselves. BTW, nanny, that is what I offer to back up my affectionate backhand, the trail of comments you are about to leave all over the site.
At March 14, 2006 6:20 PM,
coby said…
nanny_govt_sucks, the lack of a perfect correlation between CO2 rise and temperature rise does not in anyway contradict the science that indicates CO2 is the primary driver of the overall warming trend. See this article.
At March 14, 2006 9:09 PM,
Anonymous said…
"Coby, but there are others who simply bane him/it."
Other than RealClimate who is notorious for censoring posts including mine (seems to be whenever I refer to "bristlecones", "aerosols" or Mann's so-called "non-climactic adjustment" in MBH99), exactly which sites are you referring to David?
nanny_govt_sucks
At March 14, 2006 9:28 PM,
Anonymous said…
"nanny_govt_sucks, the lack of a perfect correlation between CO2 rise and temperature rise"
PERFECT?
Who said anything about a "perfect" correlation? That is your strawman.
How about something that is "somewhat close"? A 35-year divergence in the CO2/temps charts is a significant difference.
"...does not in anyway contradict the science that indicates CO2 is the primary driver of the overall warming trend. See this article."
Coby, you link to an article about aerosols causing cooling but there are many problems with that explanation as you can see in my comments to that article. So you have not yet laid the foundation for your claim that CO2 is the primary driver of any warming trend.
nanny_govt_sucks
At March 14, 2006 9:34 PM,
Anonymous said…
"BTW, nanny, that is what I offer to back up my affectionate backhand, the trail of comments you are about to leave all over the site."
Coby, the ad-hom was low. And it came after my first posting here which was quite benign. Just be a man and apologize and withdraw it so we can move on.
At March 14, 2006 9:50 PM,
coby said…
You must read here for the foundation of the CO2 causing the warming theory. All I can tell you is that you are too fixated on a temporary lack of correlation. Whatever the reason may be, it is clearly not a logical or physical impossibility that there is one.
Check here for a graph of the forcings involved over the century and keep in mind that there are differences in response times.
Also see this very nice graphic and note that sulphates, vocanic and solar forcings were all trending down in the period in question even as CO2 forcing was on the rise.
At March 14, 2006 9:53 PM,
coby said…
nanny, sorry for the comment, I meant no real offense and you are welcome to comment here.
At March 15, 2006 12:03 AM,
Anonymous said…
Apology accepted.
"You must read here for the foundation of the CO2 causing the warming theory."
I've read there and the issue of mid-century cooling is not addressed except to point to aerosols, but there are many problems with that scenario.
"All I can tell you is that you are too fixated on a temporary lack of correlation."
A 35-year lack of correlation, which is pretty significant when you are looking at a 100-year period.
"Whatever the reason may be, it is clearly not a logical or physical impossibility that there is one."
But you can't just cross your fingers and hope there is a correlation. We need to SEE that it is there.
"Check here for a graph of the forcings involved over the century and keep in mind that there are differences in response times."
This is from a computer model. Computer models do not produce evidence.
"Also see this very nice graphic and note that sulphates, vocanic and solar forcings were all trending down in the period in question even as CO2 forcing was on the rise."
Ditto.
Also, sulfates are supposed to have a regional effect which is not backed up by observations. See the aerosol thread for more problems with the aerosol explanation.
nanny_govt_sucks
At March 15, 2006 6:10 AM,
Anonymous said…
we are indeed well outside the realms of natural global variability as seen over the last two thousand years
This statement is supported by a collection of graphs, none of which were presumably intended to support the null hypothysis... Leaving aside the possibility that there exist other reconstructions which were not selected for the wikipedia article, is it not likely that the original reconstructions may have been slightly selective in their choice of source data?
At March 15, 2006 6:36 AM,
Unknown said…
First off, great site, Coby.
Second, an ad hominem, for those who don't know what it is, is a personal attack on an opponent in order to ignore or discredit their argument. It is the replacement of a premise with a personal attack. The quoted passage was not an ad hominem.
At any rate, Peter, what you describe does not amount to refutation. "Oh pishah" is not a valid refutation of data. Those who think it is are engaged in religion, not logic. Any communication with such people is a waste of your precious moments on this planent and I encourage you not to engage with them.
At March 15, 2006 8:13 AM,
coby said…
Thanks, DJEB.
Anonymous, re selective data, no I don't think that is likely, at least not the kind of selection you imply.
At March 15, 2006 8:52 AM,
coby said…
re the graphic here: http://www.giss.nasa.gov/data/simodel/, no it is not from a computer model, it is data from observations that is then fed into a computer model, input, not output.
re: the graphic here: http://en.wikipedia.org/wiki/Image:Climate_Change_Attribution.png, this is model output that shows you the breakdown of the various forcings. The observed and the model temperature trends match well, the explanation for the mid century cooling is in the forcing breakdown which is the result of physical principals, climate theory and data.
At March 15, 2006 3:34 PM,
Unknown said…
Dano, who knew Suzuki would name a motorcycle after me?
Insults are just that, insults. Crying ad hominem does not mean an ad hominem was made (though you might have a hard time explaining that to some denialists). In this case, Coby needn't worry. What he typed was a different animal.
At March 16, 2006 7:58 PM,
Lloyd Flack said…
Nanny people are exasperated with you because in climate science you seem to be looking for reasons to believe what you want to believe rather than what the evidence indicates. You are letting your political beliefs influence your opinions about natural processes.
My political opinions are probably closer to yours than they are to some of the other commenters but I accept that we do have a problem and should do something about it. I may have to accept some of the necessary actions through gritted teeth. There is no painless solution to our environmental problems. Technological improvements and changes in consumer choices are necessary parts of the solution. So unfortunately are changes in the regulatory regime. If you hope that the problem of Global Warming won't become serious and ignore the necessity of changes then the changes that will be made will be worse than they needed to have been.
At March 20, 2006 12:38 PM,
Anonymous said…
coby said...
LOL! Thanks, I'll put that in the Crackpottery list and get to it later.
March 14, 2006 2:41 PM
Keep an open mind. This is an interesting article. Maybe something to it, maybe not, but I would definitely not categorize it as crackpot. For what it is worth, the person who came up with the idea is an award winning scientist.
At March 20, 2006 1:01 PM,
coby said…
Point taken. I did remove it from that section some time ago and acknowledged that I reacted to quickly not realizing it was fresh research.
I won't presume to pass such judgement on, as you say, a recognized expert on the basis of a press release only.
Mind you, the scientists at Real Climate are not too impressed.
At March 22, 2006 7:18 PM,
coby said…
Hmm, could be a hopeless case. But speaking of loose talk...where's his evidence that .8oC in 100 years, let alone .6oC in 30, let alone the projected rate of 3oC in 100 years is within the bounds of normal variance? Climate is not a crap shoot. There are random flucuations on year to year measures and over regional distributions, but the climate is broadly deterministic over appropriate timeframes, such as decades to centuries, perhaps millenia. So adding CO2 drives the temperature up. The 120Kyr glacial cycles were not random flucuations either, they were orbital forcings amplified by ice albedo and GHG feedbacks.
The IPCC has an entire chapter devoted to Attribution and Detection of climate change
Real Climate did an article on Natural Variability and Climate Sensitivity
There is some very heady discussion in the comments of the chaotic systems not predictable article of mine and actually much more in this one.
I don't think I have a good pithy comeback for that. I just really question the premise. Even if there were other similar sudden changes in the past (and there were, catastrophically so) it does not reflect on what is happening now. Also try to remember that there is no eveidence of any changes greater than around one tenth the rate of today's in the ice core records.
There is tons of statistical work involved in attributing this change to us, but I am not familiar with it, not much of a stats buff.
Good luck!
At March 24, 2006 1:34 PM,
Anonymous said…
"Nanny people are exasperated with you because in climate science you seem to be looking for reasons to believe what you want to believe rather than what the evidence indicates."
The evidence indicates that CO2 concentrations and global temps diverged for 35 years between 1940 and 1975. That's not politics, that's an observation.
nanny_govt_sucks
At March 24, 2006 2:21 PM,
coby said…
No one has any objection to your abservation, it is trivially correct. Where your politics trumps your reason is in the conclusion that you draw from this observation and your refusal to entertain any suggested explanations.
http://illconsidered.blogspot.com/2006/03/what-about-mid-century-cooling.html
At April 04, 2006 4:28 PM,
Anonymous said…
No, the null hypothesis here is "There is a natural explanation for the warming that explains all the observations as well as the AGW model." So long as the AGW model makes successful predictions, it will be better than the null hypothesis (because the null hypothesis can make no predictions!) It's doing fairly well, but it's not quite there yet--because there is still technically a null hypothesis that goes "All the currently verified features of AGW are correct, but the remaining unconfirmed features are caused naturally." In particular, tropospheric leading needs to be explained better, and the question of the MWP needs to be settled (I would say that the evidence we're now warmer than the MWP has recently swung in favor of the hypothesis, but only recently, and hopefully we'll get a better handle on this in the next few months. Still, there are a lot of graphs out there that are just plain suspect, mostly because of their relationship with the infamous bristlecone pine data--please note that this is different from saying they're suspicious, and completely different from saying they're misleading or dishonest! Anyway, not admitting this just adds fuel to the fire, IMHO.)
By the way, that Holocene graph on Wikipedia is neat, but you should pay attention in particular to where the author says:
"Because of the limitations of data sampling, each curve in the main plot was smoothed (see methods below) and consequently, this figure can not resolve temperature fluctuations faster than approximately 300 years."
Since the modern temperature record is only about half of this level of detail, we can't yet rule out that it is not unusual. In fact, you should also pay attention to when the author says:
"It is impossible to know whether similarly large short-term temperature fluctuations may have occurred at other times, but are unresolved by the resolution available in this figure. The next 150 years will determine whether the long-term average centered on the present appears anomalous with respect to this plot."
150 years is a fairly long time...I'm just saying you can't be less critical of the graph than the author himself (or herself.)
At April 04, 2006 4:52 PM,
coby said…
Your cautions about the resolution, or lack thereof, in the proxy reconstructions are prudent, thanks for bringing it up.
I encourage any readers who have come this far to read all the descussion of that 12000 year graph here.
At April 06, 2006 1:05 AM,
Anonymous said…
This comment has been removed by a blog administrator.
At April 06, 2006 7:57 AM,
coby said…
Peter, your comment was removed because it was off topic for this thread and it was material that you have already posted on several other articles here.
At April 11, 2006 8:35 AM,
Anonymous said…
Climate has always been 'changing'; there is as such nothing really to debate about such 'change' being 'existent'. There is not with any valid reasoning an ability to cite 150 years as 'a long time' in the context of planetary processes.
There is indeed 'warming', but it is NOT due to any supposed 'Greenhouse effect' and it is at this point of 'observation and inference' that 'greenhouse rhetoric' falls into 'predetermination' within the inferences and opinions presented.
The current 'warming process' began being obvious ~15000 to ~20000 years ago, and is again obvious NOW, which is all that makes the situation of NOW 'unique'.
As such the "Null Hypothesis", if one would to even bother attempting a 'philosophical treatise' is that Humanity cannot be shown to have produced any effect in only a few decades.
You can refer to discussion and material (for further detail) contained within the links:-
http://www.climateimc.org/?q=node/312
http://www.climateimc.org/?q=node/348
To example what the 'WHO over the WHAT' rhetorical process within the 'Greenhouse Platform' is avoiding notice of is exampled within the 'Ice is melting' platform.
The Oceans represent a mass of ~0.0014x10^24 kilograms.
This is in total ~1,400,000,000 billion tonnes.
50 billion tonnes represents ~0.00000357% of the total Ocean mass and at the rate of 50 billion tonnes Nett per year (current expectation) it would take ~280,112 years for a single 1% of total Oceanic mass to be added. However only ~2% of all water is 'trapped' (some being as Ice), so to 'free' half of the total trapped reserves will take ~280 Thousand Years (at the currently estimated rate of Nett release).
At which point can we expect 'climate science' to cease making 'reports' based on only decades, propped with 'philosophical underlay'?
At which point can we expect 'climate science' to cease making a 'philosophical' platform of 'Scare, Doom and Woe', literally from nothing, to justify itself?
Perhaps more attention needs to be paid to what IS known of SCIENCE, our reality, and less to the 'authors of opinion'.
Your's, Peter K. Anderson a.k.a. Hartlod(tm)
From the PC of Peter K Anderson
E-Mail: Hartlod@bigpond.com
At December 07, 2006 4:01 PM,
Unknown said…
Just thought I'd jump back in and say there is indeed 'warming', and it IS due to the 'Greenhouse effect.'
Peter, do you do your work work for free? If not, you could be making a fortune. Your posts are the kind of stuff Exxon Mobil pays thousands of dollars for.
At February 20, 2007 5:13 PM,
Anonymous said…
"Some errors, assumptions and misconceptions to correct here, that's all." says Coby
__________________________________
The "Null Hypothesis" is the basis of all modern science, its what took humanity out of the dark ages and into the Reinnasance (sp). It is no mystery to me why a neo-Communist propagandist doesn't like the "Null Hypothesis".
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