Charles@246, Thank you. I have been accused of being pithy in the past, but usually only by people who spoke with a lisp.
Rick Baartmansays
My APS membership is up for renewal. Should I sign up for the topical group “Physics of Climate”? I’m not a climate scientist, and my brief perusal suggests this group is stocked with deniers. Is it worth the trouble?
[Response: Yes. The wider the distribution of people involved, the less likely it will be hijacked by people with agendas. There is some fascinating physics associated with climate and so your time will be repayed with interest. – gavin]
@grypo – that directory, to me, looks like his Tech Central Station file – [Willie] Soon was a regular contributor. Also articles co-written with Baliunas and with “Dave” Legates.
Ok, I missed this, and now things make a little sense. The names and transcripts that were in the Tech Central Station file were McIntyre’s. Although we can’t look into the file structure anymore (and never could look at the actual files) I pieced together the cached file names from my PC, from back when he allowed his files to be viewed. That file (TCS-DOCfile03-d/ 07-Oct-2003 11:43), if you check, was never modified after October 2003, meaning all those McIntyre files predate the release of MM03, the climate2000 site, or any other incantation of McIntyre to the wider climate world. So for whatever reason, McI’s paper was in Soon’s possession early enough to make sure this newsflash was quickly disseminated (during a Congressional Hearing, I might add).
It also explains the HackerGate 2.0 email that indicates that Mann received news about the paper from Soon’s co-worker.
My opinion is that this paper was a well coordinated, and now, neverending attack.
Even if we can tackle ONE single chapter down
the road but forcefully and effectively … we
will really accomplish A LOT!
— Willie Soon, circa 2003
Mayasays
I’m not quite sure what is to be gained from a “debate” on global warming, but Nader apparently thought it was worth the effort, so Inhofe and Markey are going to go at it.
It is dumping iron on iron-limited ocean eco systems. I don’t think it is taken seriously as a “solution”.
Re: H2So4. You are assuming that all geoengineering is shooting SO2 into the stratosphere. It isn’t. We are doing a massive geoengineering experiment right now and as far as I can tell we are not going to let up during my life time. It strikes me that it would behoove us to consider alternative geoengineering experiments to counter the on-going one should it prove deleterious to the continued existence of “civilization.” That being said, which do you think would be worse for your health: breathing trace amounts of SO2 or not eating for 6 months?
… The climate-change chapter in SuperFreakonomics is a case in point. In it, Levitt and Dubner throw their weight behind geoengineering …. Levitt is in no better a position to evaluate Myhrvold’s proposal than we are.
When an actual expert, University of Chicago climate scientist Raymond Pierrehumbert, questioned the claims in Levitt and Dubner’s writing on climate, Levitt retorted …. preemptively defensive …. covering subject matter outside your expertise, it pays to get second—and third and fourth—opinions.
… How could [Freakonomics authors] slip up in so many ways? Some … offer insights for the would-be pop-statistics writer.
———–
Source: http://www.americanscientist.org/issues/id.14344,y.0,no.,content.true,css.print/issue.aspx
John E. Pearsonsays
Hank said: “he climate-change chapter in SuperFreakonomics is a case in point. ”
of what?
Dan H.says
Richard,
I will respond to your challenge.
Using this data from CRU: http://www.metoffice.gov.uk/hadobs/hadcrut3/diagnostics/global/nh+sh/monthly
The 120-month linear trend from 1970-1980 was ~0.1C/decade. That value rose to 0.41C/decade for the period 1/73-12/82. The 120-month linear trend averaged 0.1C/decade from 1/76 – 1/97, after which it spiked up to 0.45C/decade during the period 4/92-3/02. Since then, the 120-month linear trend as decreased steadily until todays value of -0.08C/decade. That value is comparable to the period 1/67 – 12/76. I specifically chose 120-month so that the 1998 year did not carry more weight. Incidently the most recent 120-month trend is still lower than the 2/98-1/08 trend, which contained the single highest and lowest temperature anomalies in the past 15 years.
The GISS data shows a smaller range, with a high of 0.4C/decade for the 5/92-4/02 period, and the most recent 120-month trend at 0.006C/decade.
Whether you call this a “pause” as some have, or a “lack of warming” or “warming hiatus” is a matter of semantics. It is better to attempt to explain this recent occurrance rather than dismissing it altogether. That would be reminiscent fo those who tried to dismiss the warming of the 1980s.
#259–“It is better to attempt to explain this recent occurrance rather than dismissing it altogether.”
I believe the point of those who disagree with you is precisely that statistically insignificant variations are in fact not ‘better explained,’ since they are expected from time to time, given the observed variability of the temperature record.
Of course, that’s just the statistical side of it. The physical mechanisms driving the evolution of temperature trends over decadal timescales are of considerable interest, I should think, however unsurprising the ‘pause’ might be from a statistical point of view.
Claire Mathieusays
Shock as retreat of Arctic sea ice releases deadly greenhouse gas
Russian research team astonished after finding ‘fountains’ of methane bubbling to surface
Kevin,
Statistical insignificant variations are in deed expected. The difference in opinion is that there are those who feel that the change from +0.45C / decade to -0.08C / decade is insignificant over a 10-year period, whereas I do not.
This does not change the long-term trend of 0.6C / century. But the variations about and below that trend line are natural.
dhogazasays
Dan H.
Statistical insignificant variations are in deed expected. The difference in opinion is that there are those who feel that the change from +0.45C / decade to -0.08C / decade is insignificant over a 10-year period, whereas I do not.
This does not change the long-term trend of 0.6C / century.
Do you have *any* idea how self-contradictory these three sentences are?
#263–Dan, I’m not going to argue this with you at any length, but I am going to suggest that statistical significance isn’t a matter to be decided by what any of us ‘feel.’
#261–Well, funny you should ask; it’s currently being mooted on the “AGU Day 5” thread. Opinions seem to vary.
FWIW, I’d say don’t worry at all; just keep working to mitigate emissions as much and as soon as possible, ’cause this is another good reason why we need to do so.
Ray Ladburysays
Dan H., Please tell me you are not that dim. OK,Dan, one way of assessing statistical significance is to look at whether an event is rare or common, right?
Go to Woodfortrees. Plot the trend from 1977-1987. Plot the trend from 1987-1997. Chew on that one for awhile.
wilisays
#261
You are right to be very worried. Estimates of sea bed methane I have seen are orders of magnitude greater than that given in the article.
If you want independent confirmation that something is amiss with methane in the Arctic, look at the latest dots on the methane graph for Barrow, Alaska:
dhogaza,
There is nothing contradictory in those statements. One concerns the long-term trend. Another concerns the short-term trend, which often does not match the long term. The last is simply an agreement with Kevin that statistical variations exist.
The recent change in the short-term trend has a cause other than statistical variation, just as the previous change in the 1990s did. Looking at the long term, extended periods above and below the trend occur, which cannot be attributed to random variations.
J Bowerssays
266 Kevin McKinney — “FWIW, I’d say don’t worry at all; just keep working to mitigate emissions as much and as soon as possible,…”
Solar power: More than at present 74%. Less than at present 6%
Wind farms: More than at present 56%. Less than at present 19%
Oil power stations: More than at present 10%. Less than at present 47%
Coal power stations: More than at present 16%. Less than at present 43%
That actually surprised me, but probably because I hang out where a vocal minority shout out loud a lot.
Richard Simonssays
Dan @159: “I will respond to your challenge.”
You did indeed find that the trend in recent years is numerically less than the trend in previous decades. However, the challenge was to demonstrate that the difference is statistically significant, which you did not attempt.
“The difference in opinion is that there are those who feel that the change from +0.45C / decade to -0.08C / decade is insignificant over a 10-year period, whereas I do not.”
You, and various others. However, no-one has demonstrated it and all I’ve seen indicates that it is not even particularly close to being significant.
Maybe I missed some other discussion as I know a lot is being discussed?
Bob Loblawsays
Dan H. @ 263:
The difference in opinion is that you seem to think that significant/not significant is matter of opinion, whereas most scientists that I know of use standard objective statistical methods.
As long as you insist on treating this as an opinion, expect to find that scientists have the opinion that your statements are (to quote dhogaza) “self-contradictory”.
Dan H.says
Utahn,
It is entirely possible that the entire “pause” is being caused by natural variations. If you remove these variations from both the lower, recent trend and the higher, previous trend, then the resulting trend is still ~0.6C/century. Tamino and I have had a disagreement about this.
Dan H.says
No Bob,
I do not think it is a matter of opinion, contrary to what others have said here.
I responded to Richard’s request. Does anyone else here have an analysis that shows that the recent trend is similar to the previous trend.
Dan’s trying hard to sound like he knows something about the subject.
What Tamino said in thoroughly dissecting Dan H’s notion:
“… it isn’t right, which is easily confirmed statistically.” Continue reading →
Dan H.says
Hank,
Did you see my response to Tamino, with supporting evidence that he dismissed because it did not support his own view?
Bob Loblawsays
Dan H. @ 275:
Let’s look at what you said in # 263 in it entirety:
Statistical insignificant variations are in deed expected. The difference in opinion is that there are those who feel that the change from +0.45C / decade to -0.08C / decade is insignificant over a 10-year period, whereas I do not.
This does not change the long-term trend of 0.6C / century. But the variations about and below that trend line are natural.
First sentence: “statistical insignificant variations are … expected”.
Second sentence: “…opinion … feel that the change is … insignificant … whereas I do not.”
Third sentence: “does not change the long-term trend”.
Translation: you expect statistical insignificance, but you have the opinion/feel that it is not insignificant (thus rejecting the applicability of the statistical test), and yet it doesn’t change the long-term trend, so you agree it isn’t significant.
And you don’t see the self-contradiction? Oh, my.
Dan H.says
Bob,
It is entirely plausible, in fact quite likely that significant short-term trends can exist within any long-term trend. No contradiction.
I do not know why you all seem to think this is about opinions and not rely on statistical analysis.
Dan H.,
Did you even bother reading my post? I showed that there are two similar 10-year periods within the past 35 years. In fact, although both contiguous periods show little to no warming, the 20 year period shows significant warming. What this means, Dan, is that 10 years is simply too short to determine a significant climatic trend.
That is not to say the variability/noise in the system is uninteresting. It is in fact very interesting and an area of active research. It just ain’t climate… pretty much by definition. I would say that if you can cherrypick 3 10 year periods in 35 years that give little warming, then such periods are unexceptional, and they certainly do not indicate a change in the overall trend.
Richard Simonssays
Dan @ 275: “I responded to Richard’s request.”
No – I asked for you to determine if there was a statistically significant difference.
Dan @279 “I do not know why you all seem to think this is about opinions and not rely on statistical analysis.”
How can you possibly imply you alone are relying on statistical analysis, when you have avoided presenting any P values? Do you in fact understand what is being asked of you?
#279–“I do not know why you all seem to think this is about opinions and not rely on statistical analysis.”
The irony!
Dan, you’re the one who is determining statistical significance by ‘feel!’
The ten-year ‘trend’ is not significant, as determined by standard statistical tests. And that’s not a matter of opinion.
Craig Nazorsays
Dan,
I really don’t mean to drag you away from your losing position on the current debate, but I asked you some questions, and I’m feeling a little ignored.
On another blog, you said: “The UHI has been shown to contribute between 25% and 50% of the observed warming. I would call that major.”
Do you still believe that?
You also said:
“Temperatures during the last decade have not warmed”
I’m also impressed that you got Tamino to use a whole web page to debunk some of the same claims that I have been telling you were bogus for the past year. Congratulations!
RichardCsays
Dan H,
Long term trends have different uses than short term trends. Long term trends point to where climate is heading with BAU and no changes in the planet’s response. Short term trends point you to the natural variations. So, as you say, a short term trend is real and has use, and I bet everyone here agrees with you. What do you think the current short term trend has been caused by?
Dan H.says
Craig,
I do not believe that the UHI contributed more than 25% to the observed warming. There have been others who have reported that, hence the statement. Even if it only contributes 10%, I would still call that major.
As posted previously, the warming trend over the past decade is -0.08C/decade for CRU and +0.006C/decade for GISS. Neither of theses are significantly different than zero, so based on the data, I would have to answer yes.
Tamino did deote an entire thread to our arguement. He then refused to allow me to respond. I wonder what he was afraid of.
[Response: Dying of boredom I imagine. – gavin]
Dan H.says
Utahn,
Over the past 30 years, both the CRU data yield a warming of 0.16C / decade, so I would generally agree with you. However, the temperature has fluctuated such that ebvery 30 years corresponds to a half cycle. From 1881-1911 and 1941-1971, temperatures have decreased, in a pattern similar to that being observed over the past decade. In the intervening thirty years, temperatures have increased approximately 0.15C/decade. Hence, many climatologist state that temperatures will regain their upward movement after this next cycle culminates.
Dan H.says
Richard,
The cause is most likely a combination of one or more of the following:
1. Aerosols from China as claimed by James Hansen.
2. Declining solar activity as mentioned by Judith Lean.
3. The negative phases of AMO, NAO, PDO, etc. as stated by Mojib Latif and Susan Solomon.
4. Aerosols from volcanic eruptions identified by Jean-Paul Vernier.
Any one of these would result in less heat reaching the surface. I am less inclined to agree with Trenberth on the “missing heat” migrating to the depths of the oceans, until he can demonstrate why this would suddenly occur. Of this list, the oceanic effects correlate best with the past temperature record, although I would not rule out any of the others influencing the oceans through cloudiness in the temperate latitudes.
Any other thoughts?
Utahnsays
” Hence, many climatologist state that temperatures will regain their upward movement after this next cycle culminates.” So who are these many climatologists predicting 20 more years of cooling before the next oscillation? Can you give me some links to their work?
Ray Ladburysays
Dan, Please. You are positing a cycle with 60 year periodicity based on all of 2 cycles? Dude, do you understand how easy it is to hallucinate periodicities in random data. OK, Dan, another exercise for you. Graph the following series of ordered pairs
(1,2), (2,7), (3,1), (4,8), (5,2), (6,8) (7,1), (8,8), (9,2), (10,8)
Is the series periodic? If so, predict the y value for the 11th point.
If you said 4, you are correct. The y values are digits of the base of Napierian logarithms, e, and the x values are their ordinal positions in the number. Hopefully, this illustrates the danger of positing cycles without 1)lots of data, or 2)a physical mechanism.
Ric Merrittsays
Amateur etymologists can consult the OED today. Most of the website is by subscription, but the Word of the Day, linked from the front page, is available to all.
Today’s WOTD is Climate.
Since it’s the OED, you get all of the usages and history back to Latin and Greek.
wilisays
I thought I’d drop by to see if anything interesting is happening, but I find, as usual, people have allowed a troll to hijack the entire thread. What exactly is the borehole for if not for this drivel?
[Response: Unfortunately we are all too busy to deal with all this. For my part, I think we need a significantly updated method of highlighting comments, so that the worthwhile ones actually wind up at the top. The software for doing this efficiently and fairly is, however, not there yet. –eric]
SecularAnimistsays
Craig Nazor wrote to Dan H: “I’m also impressed that you got Tamino to use a whole web page to debunk some of the same claims that I have been telling you were bogus for the past year.”
Yes, Dan H has demonstrated an impressive ability to deliberately and maliciously waste people’s time with nonsense. I’m sure it gives him great satisfaction.
The only real problem with Dan H is his increasingly successful mimicry of someone who knows the science. This is the kind of performance you’d expect from a good PR guy, or someone who’s been in sales for a long time, selling the ideas. I’ve watched it for decades used against scientists. The tactic is to seem oh so reasonable to the majority audience while slipping in enough lies and distortions to get the knowledgeable listener or the scientist on the stage or radio show to lose his or her temper.
He’s very good.
I wouldn’t buy a used car or an insurance policy from this guy after watching him work the audience. But if I were a newcomer, he’d seem oh so trustworthy.
Aside to Dan — if you go to Grumbine’s site and work through the example given, you’ll understand the point the statisticians teach.
It’s the basic core understanding of elementary statistics — what we can tell, and what we can’t tell, from any _specific_ data set.
It’s a calculation done that tells you how many observations are needed, given how much they vary, before you can say there’s a probability that a trend can be detected.
For annual data, “how many” at one observation per year means how many years.
For other kinds of data, “how many” is how many observations.
Taking statistics changes how you view the world, and gives you a common language you can use talking to and understanding scientists.
“Plant studies miss the full effect of climate change
16:36 15 December 2011 by Peter Aldhous
For similar stories, visit the Climate Change Topic Guide
Climate change is affecting plants’ seasonal activities more strongly than biological experiments suggest. The finding suggests that such studies may have to be reworked to get a better picture of the effects of global warming.
“This is huge,” says Benjamin Cook, a climate scientist at NASA’s Goddard Institute for Space Studies in New York, and a member of the team behind the study. “We are relying heavily on these experiments to predict what will happen 100 years from now.”….”
J Bowerssays
Dr. Mark Roberts, Polar Oceanographer and Senior Lecturer in Environmental Science, writes a rebuttal to the GWPF’s latest nonsense, spurred by the manufactroversy over Frozen Planet’s polar bear footage, for the Open University.
Charles@246, Thank you. I have been accused of being pithy in the past, but usually only by people who spoke with a lisp.
My APS membership is up for renewal. Should I sign up for the topical group “Physics of Climate”? I’m not a climate scientist, and my brief perusal suggests this group is stocked with deniers. Is it worth the trouble?
[Response: Yes. The wider the distribution of people involved, the less likely it will be hijacked by people with agendas. There is some fascinating physics associated with climate and so your time will be repayed with interest. – gavin]
From the old Soon thread
Ok, I missed this, and now things make a little sense. The names and transcripts that were in the Tech Central Station file were McIntyre’s. Although we can’t look into the file structure anymore (and never could look at the actual files) I pieced together the cached file names from my PC, from back when he allowed his files to be viewed. That file (TCS-DOCfile03-d/ 07-Oct-2003 11:43), if you check, was never modified after October 2003, meaning all those McIntyre files predate the release of MM03, the climate2000 site, or any other incantation of McIntyre to the wider climate world. So for whatever reason, McI’s paper was in Soon’s possession early enough to make sure this newsflash was quickly disseminated (during a Congressional Hearing, I might add).
It also explains the HackerGate 2.0 email that indicates that Mann received news about the paper from Soon’s co-worker.
My opinion is that this paper was a well coordinated, and now, neverending attack.
I’m not quite sure what is to be gained from a “debate” on global warming, but Nader apparently thought it was worth the effort, so Inhofe and Markey are going to go at it.
http://www.tulsaworld.com/news/article.aspx?subjectid=335&articleid=20111213_335_0_WASHIN153120
The ever-amusing Captcha says: government shoral
227 Ed asked about geritol.
It is dumping iron on iron-limited ocean eco systems. I don’t think it is taken seriously as a “solution”.
Re: H2So4. You are assuming that all geoengineering is shooting SO2 into the stratosphere. It isn’t. We are doing a massive geoengineering experiment right now and as far as I can tell we are not going to let up during my life time. It strikes me that it would behoove us to consider alternative geoengineering experiments to counter the on-going one should it prove deleterious to the continued existence of “civilization.” That being said, which do you think would be worse for your health: breathing trace amounts of SO2 or not eating for 6 months?
http://www.agu.org/journals/jg/jg1102/2010JG001441/2010jg001441-op01-tn-350x.jpg
Scary chart.
From: http://www.agu.org/pubs/crossref/2011/2010JG001441.shtml
JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 116, G02007, 16 PP., 2011
doi:10.1029/2010JG001441
Multidecadal variability of atmospheric methane, 1000–1800 C.E.
… The climate-change chapter in SuperFreakonomics is a case in point. In it, Levitt and Dubner throw their weight behind geoengineering …. Levitt is in no better a position to evaluate Myhrvold’s proposal than we are.
When an actual expert, University of Chicago climate scientist Raymond Pierrehumbert, questioned the claims in Levitt and Dubner’s writing on climate, Levitt retorted …. preemptively defensive …. covering subject matter outside your expertise, it pays to get second—and third and fourth—opinions.
… How could [Freakonomics authors] slip up in so many ways? Some … offer insights for the would-be pop-statistics writer.
———–
Source: http://www.americanscientist.org/issues/id.14344,y.0,no.,content.true,css.print/issue.aspx
Hank said: “he climate-change chapter in SuperFreakonomics is a case in point. ”
of what?
Richard,
I will respond to your challenge.
Using this data from CRU:
http://www.metoffice.gov.uk/hadobs/hadcrut3/diagnostics/global/nh+sh/monthly
The 120-month linear trend from 1970-1980 was ~0.1C/decade. That value rose to 0.41C/decade for the period 1/73-12/82. The 120-month linear trend averaged 0.1C/decade from 1/76 – 1/97, after which it spiked up to 0.45C/decade during the period 4/92-3/02. Since then, the 120-month linear trend as decreased steadily until todays value of -0.08C/decade. That value is comparable to the period 1/67 – 12/76. I specifically chose 120-month so that the 1998 year did not carry more weight. Incidently the most recent 120-month trend is still lower than the 2/98-1/08 trend, which contained the single highest and lowest temperature anomalies in the past 15 years.
The GISS data shows a smaller range, with a high of 0.4C/decade for the 5/92-4/02 period, and the most recent 120-month trend at 0.006C/decade.
Whether you call this a “pause” as some have, or a “lack of warming” or “warming hiatus” is a matter of semantics. It is better to attempt to explain this recent occurrance rather than dismissing it altogether. That would be reminiscent fo those who tried to dismiss the warming of the 1980s.
#259–“It is better to attempt to explain this recent occurrance rather than dismissing it altogether.”
I believe the point of those who disagree with you is precisely that statistically insignificant variations are in fact not ‘better explained,’ since they are expected from time to time, given the observed variability of the temperature record.
Of course, that’s just the statistical side of it. The physical mechanisms driving the evolution of temperature trends over decadal timescales are of considerable interest, I should think, however unsurprising the ‘pause’ might be from a statistical point of view.
Shock as retreat of Arctic sea ice releases deadly greenhouse gas
Russian research team astonished after finding ‘fountains’ of methane bubbling to surface
http://www.independent.co.uk/environment/climate-change/shock-as-retreat-of-arctic-sea-ice-releases-deadly-greenhouse-gas-6276134.html
I remember reading an article before about that line of research, with all sorts of fear-inducing words. How much should one worry about this?
Decade or two trends don’t prove much:
http://www.vukcevic.talktalk.net/CET-100-150-100.htm
Kevin,
Statistical insignificant variations are in deed expected. The difference in opinion is that there are those who feel that the change from +0.45C / decade to -0.08C / decade is insignificant over a 10-year period, whereas I do not.
This does not change the long-term trend of 0.6C / century. But the variations about and below that trend line are natural.
Dan H.
Do you have *any* idea how self-contradictory these three sentences are?
#263–Dan, I’m not going to argue this with you at any length, but I am going to suggest that statistical significance isn’t a matter to be decided by what any of us ‘feel.’
#261–Well, funny you should ask; it’s currently being mooted on the “AGU Day 5” thread. Opinions seem to vary.
FWIW, I’d say don’t worry at all; just keep working to mitigate emissions as much and as soon as possible, ’cause this is another good reason why we need to do so.
Dan H., Please tell me you are not that dim. OK,Dan, one way of assessing statistical significance is to look at whether an event is rare or common, right?
Go to Woodfortrees. Plot the trend from 1977-1987. Plot the trend from 1987-1997. Chew on that one for awhile.
#261
You are right to be very worried. Estimates of sea bed methane I have seen are orders of magnitude greater than that given in the article.
If you want independent confirmation that something is amiss with methane in the Arctic, look at the latest dots on the methane graph for Barrow, Alaska:
http://www.esrl.noaa.gov/gmd/dv/iadv/graph.php?code=BRW&program=ccgg&type=ts
dhogaza,
There is nothing contradictory in those statements. One concerns the long-term trend. Another concerns the short-term trend, which often does not match the long term. The last is simply an agreement with Kevin that statistical variations exist.
The recent change in the short-term trend has a cause other than statistical variation, just as the previous change in the 1990s did. Looking at the long term, extended periods above and below the trend occur, which cannot be attributed to random variations.
266 Kevin McKinney — “FWIW, I’d say don’t worry at all; just keep working to mitigate emissions as much and as soon as possible,…”
You’ll like this, then.
British public strongly support renewable energy, survey says
Solar power: More than at present 74%. Less than at present 6%
Wind farms: More than at present 56%. Less than at present 19%
Oil power stations: More than at present 10%. Less than at present 47%
Coal power stations: More than at present 16%. Less than at present 43%
That actually surprised me, but probably because I hang out where a vocal minority shout out loud a lot.
Dan @159: “I will respond to your challenge.”
You did indeed find that the trend in recent years is numerically less than the trend in previous decades. However, the challenge was to demonstrate that the difference is statistically significant, which you did not attempt.
“The difference in opinion is that there are those who feel that the change from +0.45C / decade to -0.08C / decade is insignificant over a 10-year period, whereas I do not.”
You, and various others. However, no-one has demonstrated it and all I’ve seen indicates that it is not even particularly close to being significant.
Dan, weren’t we just talking about how removing natural variation eliminates any “pause” ? And shows an underlying 2C per century trend rather than 0.6?
https://www.realclimate.org/index.php/archives/2011/12/global-temperature-news/
Maybe I missed some other discussion as I know a lot is being discussed?
Dan H. @ 263:
The difference in opinion is that you seem to think that significant/not significant is matter of opinion, whereas most scientists that I know of use standard objective statistical methods.
As long as you insist on treating this as an opinion, expect to find that scientists have the opinion that your statements are (to quote dhogaza) “self-contradictory”.
Utahn,
It is entirely possible that the entire “pause” is being caused by natural variations. If you remove these variations from both the lower, recent trend and the higher, previous trend, then the resulting trend is still ~0.6C/century. Tamino and I have had a disagreement about this.
No Bob,
I do not think it is a matter of opinion, contrary to what others have said here.
I responded to Richard’s request. Does anyone else here have an analysis that shows that the recent trend is similar to the previous trend.
Dan’s trying hard to sound like he knows something about the subject.
What Tamino said in thoroughly dissecting Dan H’s notion:
“… it isn’t right, which is easily confirmed statistically.”
Continue reading →
Hank,
Did you see my response to Tamino, with supporting evidence that he dismissed because it did not support his own view?
Dan H. @ 275:
Let’s look at what you said in # 263 in it entirety:
First sentence: “statistical insignificant variations are … expected”.
Second sentence: “…opinion … feel that the change is … insignificant … whereas I do not.”
Third sentence: “does not change the long-term trend”.
Translation: you expect statistical insignificance, but you have the opinion/feel that it is not insignificant (thus rejecting the applicability of the statistical test), and yet it doesn’t change the long-term trend, so you agree it isn’t significant.
And you don’t see the self-contradiction? Oh, my.
Bob,
It is entirely plausible, in fact quite likely that significant short-term trends can exist within any long-term trend. No contradiction.
I do not know why you all seem to think this is about opinions and not rely on statistical analysis.
http://moregrumbinescience.blogspot.com/2009/01/results-on-deciding-trends.html
http://moregrumbinescience.blogspot.com/2009/03/misleading-yourself-with-graphs.html
Not sure what time frames we’re talking about Dan, but do you at least agree that the last 30 years is 0.2 C per decade a la Foster and Rahmstorf?
http://tamino.wordpress.com/2011/01/21/phil-jones-was-wrong/
Dan H.,
Did you even bother reading my post? I showed that there are two similar 10-year periods within the past 35 years. In fact, although both contiguous periods show little to no warming, the 20 year period shows significant warming. What this means, Dan, is that 10 years is simply too short to determine a significant climatic trend.
That is not to say the variability/noise in the system is uninteresting. It is in fact very interesting and an area of active research. It just ain’t climate… pretty much by definition. I would say that if you can cherrypick 3 10 year periods in 35 years that give little warming, then such periods are unexceptional, and they certainly do not indicate a change in the overall trend.
Dan @ 275: “I responded to Richard’s request.”
No – I asked for you to determine if there was a statistically significant difference.
Dan @279 “I do not know why you all seem to think this is about opinions and not rely on statistical analysis.”
How can you possibly imply you alone are relying on statistical analysis, when you have avoided presenting any P values? Do you in fact understand what is being asked of you?
#279–“I do not know why you all seem to think this is about opinions and not rely on statistical analysis.”
The irony!
Dan, you’re the one who is determining statistical significance by ‘feel!’
The ten-year ‘trend’ is not significant, as determined by standard statistical tests. And that’s not a matter of opinion.
Dan,
I really don’t mean to drag you away from your losing position on the current debate, but I asked you some questions, and I’m feeling a little ignored.
On another blog, you said: “The UHI has been shown to contribute between 25% and 50% of the observed warming. I would call that major.”
Do you still believe that?
You also said:
“Temperatures during the last decade have not warmed”
Do you still believe that?
http://news.change.org/stories/new-film-takes-an-inside-look-at-fearless-climate-activist-feats
(Posted under the name of “Dan Johnson.”)
I’m also impressed that you got Tamino to use a whole web page to debunk some of the same claims that I have been telling you were bogus for the past year. Congratulations!
Dan H,
Long term trends have different uses than short term trends. Long term trends point to where climate is heading with BAU and no changes in the planet’s response. Short term trends point you to the natural variations. So, as you say, a short term trend is real and has use, and I bet everyone here agrees with you. What do you think the current short term trend has been caused by?
Craig,
I do not believe that the UHI contributed more than 25% to the observed warming. There have been others who have reported that, hence the statement. Even if it only contributes 10%, I would still call that major.
As posted previously, the warming trend over the past decade is -0.08C/decade for CRU and +0.006C/decade for GISS. Neither of theses are significantly different than zero, so based on the data, I would have to answer yes.
Tamino did deote an entire thread to our arguement. He then refused to allow me to respond. I wonder what he was afraid of.
[Response: Dying of boredom I imagine. – gavin]
Utahn,
Over the past 30 years, both the CRU data yield a warming of 0.16C / decade, so I would generally agree with you. However, the temperature has fluctuated such that ebvery 30 years corresponds to a half cycle. From 1881-1911 and 1941-1971, temperatures have decreased, in a pattern similar to that being observed over the past decade. In the intervening thirty years, temperatures have increased approximately 0.15C/decade. Hence, many climatologist state that temperatures will regain their upward movement after this next cycle culminates.
Richard,
The cause is most likely a combination of one or more of the following:
1. Aerosols from China as claimed by James Hansen.
2. Declining solar activity as mentioned by Judith Lean.
3. The negative phases of AMO, NAO, PDO, etc. as stated by Mojib Latif and Susan Solomon.
4. Aerosols from volcanic eruptions identified by Jean-Paul Vernier.
Any one of these would result in less heat reaching the surface. I am less inclined to agree with Trenberth on the “missing heat” migrating to the depths of the oceans, until he can demonstrate why this would suddenly occur. Of this list, the oceanic effects correlate best with the past temperature record, although I would not rule out any of the others influencing the oceans through cloudiness in the temperate latitudes.
Any other thoughts?
” Hence, many climatologist state that temperatures will regain their upward movement after this next cycle culminates.” So who are these many climatologists predicting 20 more years of cooling before the next oscillation? Can you give me some links to their work?
Dan, Please. You are positing a cycle with 60 year periodicity based on all of 2 cycles? Dude, do you understand how easy it is to hallucinate periodicities in random data. OK, Dan, another exercise for you. Graph the following series of ordered pairs
(1,2), (2,7), (3,1), (4,8), (5,2), (6,8) (7,1), (8,8), (9,2), (10,8)
Is the series periodic? If so, predict the y value for the 11th point.
If you said 4, you are correct. The y values are digits of the base of Napierian logarithms, e, and the x values are their ordinal positions in the number. Hopefully, this illustrates the danger of positing cycles without 1)lots of data, or 2)a physical mechanism.
Amateur etymologists can consult the OED today. Most of the website is by subscription, but the Word of the Day, linked from the front page, is available to all.
Today’s WOTD is Climate.
Since it’s the OED, you get all of the usages and history back to Latin and Greek.
I thought I’d drop by to see if anything interesting is happening, but I find, as usual, people have allowed a troll to hijack the entire thread. What exactly is the borehole for if not for this drivel?
[Response: Unfortunately we are all too busy to deal with all this. For my part, I think we need a significantly updated method of highlighting comments, so that the worthwhile ones actually wind up at the top. The software for doing this efficiently and fairly is, however, not there yet. –eric]
Craig Nazor wrote to Dan H: “I’m also impressed that you got Tamino to use a whole web page to debunk some of the same claims that I have been telling you were bogus for the past year.”
Yes, Dan H has demonstrated an impressive ability to deliberately and maliciously waste people’s time with nonsense. I’m sure it gives him great satisfaction.
The only real problem with Dan H is his increasingly successful mimicry of someone who knows the science. This is the kind of performance you’d expect from a good PR guy, or someone who’s been in sales for a long time, selling the ideas. I’ve watched it for decades used against scientists. The tactic is to seem oh so reasonable to the majority audience while slipping in enough lies and distortions to get the knowledgeable listener or the scientist on the stage or radio show to lose his or her temper.
He’s very good.
I wouldn’t buy a used car or an insurance policy from this guy after watching him work the audience. But if I were a newcomer, he’d seem oh so trustworthy.
[Response: You have him pegged exactly Hank.–Jim]
Aside to Dan — if you go to Grumbine’s site and work through the example given, you’ll understand the point the statisticians teach.
It’s the basic core understanding of elementary statistics — what we can tell, and what we can’t tell, from any _specific_ data set.
It’s a calculation done that tells you how many observations are needed, given how much they vary, before you can say there’s a probability that a trend can be detected.
For annual data, “how many” at one observation per year means how many years.
For other kinds of data, “how many” is how many observations.
Taking statistics changes how you view the world, and gives you a common language you can use talking to and understanding scientists.
It would be a good idea.
http://www.newscientist.com/article/dn21292-plant-studies-miss-the-full-effect-of-climate-change.html
“Plant studies miss the full effect of climate change
16:36 15 December 2011 by Peter Aldhous
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