By Steven Goddard
[see important addendum added to end of article ~ ctm]
[Note: The title and conclusion are wrong due to bias in the start/end point of the graph, the mistake was noted by Steven immediately after publication, and listed below as an addendum. I had never seen the article until after the correction was applied due to time difference in AU. My apologies to readers. I’ll leave it up (note altered title) as an example of what not to do when graphing trends, to illustrate that trends are very often slaves to endpoints. – Anthony]
JAXA Arctic Ice measurement just had its 8th birthday. They have been measuring Arctic ice extent since late June, 2002.
http://www.ijis.iarc.uaf.edu/en/home/seaice_extent.htm
We normally see year over year ice graphs displayed in the format above, with each year overlaid on top of previous years. The graph below just shows the standard representation of a time series, with the linest() trend.
As you can see, Arctic ice extent has been increasing by nearly 50,000 km² per year. Over the eight year record, that is an increase in average ice extent of about the size of California. More proof that the Arctic is melting down – as we are constantly reminded. Spreadsheet is here.
How do we explain this? There has been more ice during winter, paralleling the record winter snow in the Northern Hemisphere. Meanwhile in the Southern Hemisphere, ice extent is at a record high for the date.
Size matters, but I’m guessing that Nobel Prize winner Al Gore didn’t share this information with his masseuse.
Addendum:
I realized after publication that this analysis is biased by the time of year which the eighth anniversary occurred. While the linest() calculation uses eight complete cycles, it would produce different slopes depending on the date of the anniversary. For instance, had the anniversary occurred in March, the trend line would be less steep and perhaps negative.
This is always a problem with graphing any cyclical trend, but the short length of the record (8 years) makes it more problematic than what would be seen in a 30 year record.
Wayne Findley says “…a real-time example of the right way to do science…”
Others before him in comments have made similar statements.
This is totally wrong on several different fronts.
First, others did the science, the blog post was just poorly thought out instant analysis looking for a “Gotcha!” moment. Owning Excel or Mathematica does not a scientist make.
Second, peer review prior to publication prevents an author from making a bonehead mistake and possibly ruining a reputation. We all make mistakes so it’s in our own self-interest to have our work double-checked by someone else before we go public with it.
Third, peer review prior to publication prevents non-expert readers from being misinformed or mislead. An expert reader can spot the mistakes. The non-expert is more likely to accept the erroneous information without questioning it. Look at how many comments here cheered the original post. They failed the peer review panel test. How many read the original post and haven’t returned to see the correction? They’re now spreading bad information to others.
As for the addendum and “I realized after publication …” it would probably be more accurate to say, “It was pointed out to me after publication …”
Reply: To clear up any timeline issues. He sent me the email with the correction long before he could have seen a single comment as none had yet been approved. ~ ctm
To those who critcising, even demanding removal of this post: If only warmist scientists were so humble. This was exactly what I I thought before reading the first comment. Sara Chan confirmed That I was not alone in thinking this.:
Sara Chan says:
July 2, 2010 at 2:56 pm
“I realized after publication that this analysis is biased…”
Wouldn’t it be wonderful if professional climate scientists admitted errors so readily? Okay, I’m dreaming.
SCIENCE
If you’re not making mistakes, you’re doing it wrong.
If your not correcting your mistakes, you’re doing it really wrong.
If you’re not accepting that you’ve made mistakes, you’re not doing it at all.
Great comment Sarah.
I cannot help but believe that Mr Goddard is a mischievous person and did this on purpose. It is now established that Dr Hansen does not know what he is doing and should get out of the kitchen. Congratulations, well done.
But what IS the correct result? Is “Les Johnson says: July 2, 2010 at 4:32 pm” right?
Kevin O’Neill says:
July 3, 2010 at 2:20 am
“Peer Review” has shown time and again that just the mention of CO2 and warming is an automatic approval no matter the outlandished or wild theory.
There are so many specialized fields that how can a “Peer-Reviewer” be an expert in all those fields to catch errors? Spelling mistakes is the editors staff’s job.
When it is failed to understand new science due to the lack of education in certain areas, they resort to the old theories that have kept the science community going.
Proxies are the immitation of actual data and are extrapulated to give the immitation of the act or data. Old timers have aching bones that tell when damp weather is coming.
😉
Since we’re clearly dealing with a chaotic, forced oscillation, why shouldn’t one start from June 21st 2002 (longest day in Northern hemisphere) to June 21st 2010. That would align to the solar maximum in NH at each end of the series and happens to give an average annual growth of approx 52,700 assuming I’ve done my sums correctly and the supplied data is correct. Not aligning to such a basic celestial cycle will surely introduce all sorts of post normal noise into the debate.
Steve,
Thank you for your contributions, and compliments to Anthony managing and everyone else participating in this important community effort.
I particularly compliment you on your article about Venus atmospheric pressure vs greenhouse effect and the elaborations by Lubos Motl.
http://wattsupwiththat.com/2010/05/06/hyperventilating-on-venus/http://motls.blogspot.com/2010/05/hyperventilating-on-venus.html
http://www.timothybirdnow.com/?p=3107
One reason why I check in to this excellent site from time to time is to get the unbiased calibration on sea ice area /extent during the peak seasons north and south. I want to see for myself if the physical life conditions on Earth in general – and on the polar caps in particular – are truly threatened, as politicians, alleged scientists and media insist. I have a space science and electronic engineering background and my skepticism was triggered the moment I heard “the science is settled”, “these are the threats” and “we have to do this” and “everybody not cooperating will be classified as immoral. I have lived in the Arctic through two winters in a beautiful scenery at the sea, overlooking glaciers and fjords with polar bears and other wild animals close by. I have stayed onshore Antarctica and have traveled on the high seas and spent much of my lifetime by the ocean.
Up till now I have found no justification what-so-ever for alarm and the extensive new policies
and austerity measures proposed and imposed by governments and organizations. The role of
mainstream media appears equally insane – one of cheating and deception. With this site and thread I find some relief and observe honest and open ‘peer review’ truly working and that sometimes it’s back to the drawing board, as it should be.
I observe that since the sea ice is currently growing fast in Antarctica, the tactical focus is currently on the symbol case of the northern hemisphere ARCTIC SEA ICE MINIMA allegedly “threatening the polar bear”. “The sea ice is melting away and the polar bear may go extinct”. It is indisputable that whereas the sea ice area troughs each year at the beginning of the time series from 1979 onwards were mostly at or above 5 million sq km, they dropped gradually to below 3, a loss of about 40% by September 2007. We should take into account that to some people are seriously concerned about this. The world is anxiously awaiting proof of recovery which may take an equally long time to materialize.
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.area.arctic.png
I hold the view that the earth temperature system is inherently stable and will automatically compensate for an increase in one greenhouse gas such as CO2 by reducing the content of the dominant greenhouse gas – water vapor – to re-establish status quo. The Earth has its own built-in thermostat.
“son of mulder says:
July 3, 2010 at 4:20 am
Since we’re clearly dealing with a chaotic, forced oscillation, why shouldn’t one start from June 21st 2002 (longest day in Northern hemisphere) to June 21st 2010.”
I would suggest to start 16 March 2003 and end 15 March 2010.
Just a few points of clarification:
My post yesterday at 2:31 p.m., telling Steve that his post should be retracted was made prior to the title being changed. Yes, he’d made his first addendum, but even with that addendum, the title itself (at the time) was misleading, so it was on that basis that I made my first comment about a retraction. I was completely correct to ask for a retraction based on the state of affairs. Instead, Anthony and Steve came out with a brilliant way to turn the whole episode into a learning experience, by not retracting but redacting, which was even better. When I saw this redaction later on in the evening, I complimented them for it.
IMO, an error was made, a correct reaction to that error was made by both myself (et. al.) and then a very smart final solution to the error was made by Anthony & Steve. I think everyone behaved quite professionally, and really, to criticize anyone in this entire situation is to look for fault where there is none.
Be that as it may, this graph:
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/seaice.anomaly.arctic.png
and this graph:
http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/sea.ice.anomaly.timeseries.jpg
Are far more indicative of the general trend of Arctic Sea ice over the longest period of which we have reliable data…and if Steve or Anthony disagree with that contention, I’d sure like to hear why.
Reply: Timestamps show when you made comments, not when they are approved. Steve had emailed me before any comments were approved, before he could see any of them. I approved the backlog of comments first, then edited the original post when I sat down at the desk. His email was sent at 2:19 pm Pacific.~ ctm
Kevin O’Neill
I realized my mistake immediately after the post came up. I just was not thinking clearly when I wrote it at 5 AM.
R. Gates says:
July 2, 2010 at 9:59 pm
You may want to start here, for some general background:
http://www.aip.org/history/climate/chaos.htm
http://www.abarim-publications.com/ChaosTheoryIntroduction.html
http://www.12manage.com/methods_lorenz_chaos_theory.html
In a nutshell, a system, such as the climate will attempt to maintain equalibrium, and even appear as a linear system, (i.e. you get a definite predictable change based on a known set of inputs). But of course, what we know is that the climate does not work that way, and that a system undergoing change, such as our atmosphere is now, with the addition of a historically and geologically large influx of CO2, may reach a tipping point where it suddenly and unpredictably goes into a whole new state of affairs. This is NOT a random event, but rather is deterministic, but is not predictable.
********************************************************************
I have always appreciated your posts; one of the reasons I check this site, daily. ~regards
‘conclusion are wrong due to bias in the start/end point of the graph,’
Funny, I understand it as the conclusion is correct, but that the context might be biased. But that seem to be the dilemma with climatological statistics, you’re always biased since you leave out the limiting rules that sets a more proper context.
Who decides which start and end point to use within a set time frame? Who decided about the time frame?
If you frame the correct context, the conclusion is not based on a biased time frame. It’s the correct context that’s supposed to make the statistics, so to speak, not making up a context with what ever statistic.
A similar problem is currently being treated over at “The Blackboard” concerning UAH-Temperatures. June 2010 was not as warm as June 1998, and the El Niño-Year 2010 will probably end up cooler than the (comparable) El Niño-Year 1998. So is there any indication of a warming of 0.2°C/decade as prognosticated?
It would be proper to calculate a trend from (the peak in) 1998 to (the peak in) 2010. One would probably get no significant warming or cooling.
” Alexej Buergin says:
July 3, 2010 at 4:51 am
I would suggest to start 16 March 2003 and end 15 March 2010″
I make that approx -38,700 shrinkage per year quite a turnaround from 52,700 growth
and
“R. Gates says:
July 2, 2010 at 9:59 pm
……But of course, what we know is that the climate does not work that way, and that a system undergoing change, such as our atmosphere is now, with the addition of a historically and geologically large influx of CO2, may reach a tipping point where it suddenly and unpredictably goes into a whole new state of affairs. This is NOT a random event, but rather is deterministic, but is not predictable. ”
How often has this happened since 2002? Should one expect a tipping transistion to be dramatic or even detectable? What’s the probability a tipping transition will be significantly beneficial vs significantly harmful vs neither?
Maybe because it is chaotic the climate tips quite often even when there are no changes to drivers.
Who’s keeping count with their tipping detector?
Kevin O’Neill says:
July 3, 2010 at 2:20 am
“…….. peer review prior to publication prevents an author from making a bonehead mistake and possibly ruining a reputation. ……..”
Uhmm,…You’ve had plenty of time to rethink that assertion. Much more time than stevegoddard took to correct his. Are you stating that “peer-reviewed” publications can’t be wrong? The reason why I ask is because I think even you can spot some “peer-reviewed” science that is blatantly in error, in fact, if you had bother to read this thread, it points to a couple. Maybe you should have had someone read your statement before clicking on the “Post Comment” button.
Speaking of Antarctic sea ice, anyone care to comment on this study: http://www.nicholas.duke.edu/thegreengrok/whaleresearch#comments
Using a 365-day running average, I get an annualized ice extent rate of approx. -67,000 km^2/year, over the duration of the JAXA dataset which is mid-2002 to present.
Graph is at http://img155.imageshack.us/img155/3140/arcticicetrailingaverag.gif
However, the longer-term (30-year) trend at http://arctic.atmos.uiuc.edu/cryosphere/IMAGES/global.daily.ice.area.withtrend.jpg is clearly of a smaller magnitude. This can be caused by (a) sea ice trend changing — that is, the trend was less earlier in the 30-year record, reducing the average trend; or (b) estimate unduly affected by the endpoints of the JAXA record. Or a combination of both.
” son of mulder says:
July 3, 2010 at 7:04 am
I make that approx -38,700 shrinkage per year quite a turnaround from 52,700 growth”
So if this were a linear and not a cyclical business, the North Pole will be ice free in September 2138?
Some misc, comments.
1. As has been stated, including by Steve, doing a linear trend on cyclic data is folly. The slope of the trend is counter to where the start date is in the cycle. In this case, its a positive slope as ice starts to melt, and a negative slope as the sea starts freezing. Any slope should be calculated on anomalies, as someone else has noted here. This answers the question of why anomalies are used, at least for me.
2. Peer review. Some feel that that peer reviewed literature is the only real science, and that it is less likely to be shown to be in error. The two articles below (peer reviewed!), suggest that 2/3 of papers published in medical journals end up being contradicted, while the number in economic journals is suggested to be close to 100%. This of course, raises a potential paradox about these papers and their accuracy.
http://www.plosmedicine.org/article/info:doi/10.1371/journal.pmed.0020124
http://www.jstor.org/pss/2138833?cookieSet=1
3. The “peer” review here, is shown to be quick and non-partisan. Or rather, both sides of the issue and non-partisan. But its definitely not reviewed ONLY by your friends and co-authors.
4. Redaction is preferred to retraction. A quick deletion would not have invited the comments and discussion that occurred. Many people, myself included, now know of some limits of trends, that they were not aware of previously. This would not have happened if the article had been “disappeared”.
5. On spotting errors in your work. At least for me, I can better spot errors after publishing or printing, then before hand on the monitor. On important papers, I routinely print a copy, and proof that. I have no idea why the difference.
6. Circadian rhythm. The lowest point in the rhythm is between 5 and 6 AM. Most single vehicle fatalities are between 2 AM and 6 AM. Chernobyl, Three Mile Island and the Exxon Valdez all occurred in this time period. Cognitive function and judgment are at reduced levels.
Alexej Buergin
Interesting point! We always get bashed for doing peak-to-peak UAH, when in fact it is the correct way to measure the trend. Guess our friends want to have it both ways.
Kevin O’Neill says:
July 3, 2010 at 2:20 am
Wayne Findley says “…a real-time example of the right way to do science…”
Others before him in comments have made similar statements.
This is totally wrong on several different fronts.
First, others did the science, the blog post was just poorly thought out instant analysis looking for a “Gotcha!” moment. Owning Excel or Mathematica does not a scientist make.
Second, peer review prior to publication prevents an author from making a bonehead mistake and possibly ruining a reputation. We all make mistakes so it’s in our own self-interest to have our work double-checked by someone else before we go public with it.
Third, peer review prior to publication prevents non-expert readers from being misinformed or mislead. An expert reader can spot the mistakes. The non-expert is more likely to accept the erroneous information without questioning it. Look at how many comments here cheered the original post. They failed the peer review panel test. How many read the original post and haven’t returned to see the correction? They’re now spreading bad information to others.
As for the addendum and “I realized after publication …” it would probably be more accurate to say, “It was pointed out to me after publication …”
Your remarks are so way out of line as to be ludicrous.
First, this is blog is not a published journal — as if you didn’t know …
Second, you come off with the condescending arrogance of a perfectionist demanding that only certain ‘recognized’ people be allowed to post on matters of science. Allow me to remind you that many men and women of science never had any kind of ‘degree’ by which to proclaim some kind of self-importance to the rest of the world.
Third, and from what I’ve been able to discover, so-called peer review is nought but a good ol’ boy’s club wherein the chosen few are given notice, and the rest are disparaged, ignored, condemned, and otherwise relegated to one or another backwater in science.
Then you have the nerve to declare that the unwashed, ill-informed hoi polloi will now travel forth and proclaim an error to be true. Well, it that is to be so, then they will also reference the place of their new found knowledge, whereupon another will discover the corrected facts of the matter, and thence be even better informed yet.
But you won’t have any of that, preferring as you apparently do, that all science should be published in squeaky-clean published journals available only to the cadre of insiders and those fortunate enough to be both aware of them, as well as possessing the wherewithal to obtain and peruse them.
Heaven forbid that real science should ever be readily available to the commoners, or the lay person, lest they actually become informed of matters and ask serious questions which the cadre refuses to address in an honest, forthright and open manner for all the world to see.
Yes, better to keep the unwashed masses just as dumb as possible, as that way they are better managed like herds of cows in the field.
Les Johnson
Linear trends through cyclical data forms the entire basis of the IPCC’s raison d’être
Is it possible that the reason the warmists here want the article retracted is so that no one sees the proper way to address one’s mistakes? I really think that leaving this up as an example of what to do when one makes a mistake is a big score for the sceptics and shows the problem with peer-reviewed “official” work. I work in a lab where honestly some of the early papers should be retracted because they can’t be reproduced and are flat-out wrong. But it doesn’t happen because it looks bad for the group, looks bad for the journal/editors, and looks bad for the whole field in general (since they provided the peer reviewers). It’s just a real double edged sword because it’s prevented me from publishing some of my work because, although the best out there, it is NOT better than what the lab previously CLAIMED to do…grr. I can easily see problems like this cropping up in other areas like climate science.
-Scott
Les Johnson says:
July 3, 2010 at 10:00 am
You make some excellent points here. I especially agree with your comments about the peer reviewed literature being heavily in error. In my own field, I’ve encountered only a small percentage of papers that have “no errors” (that we know of yet). The percentage with very poor errors (that lead the reader to seriously wrong conclusions) is surprisingly high. And my work is in a “hard science”!
-Scott
Scott
Given that peer-reviewed articles frequently contain mutually contradictory conclusions, it seems a safe bet that there are many errors being published.
Scott says:
July 3, 2010 at 11:45 am
Is it possible that the reason the warmists here want the article retracted is so that no one sees the proper way to address one’s mistakes? I really think that leaving this up as an example of what to do when one makes a mistake is a big score for the sceptics and shows the problem with peer-reviewed “official” work. I work in a lab where honestly some of the early papers should be retracted because they can’t be reproduced and are flat-out wrong. But it doesn’t happen because it looks bad for the group, looks bad for the journal/editors, and looks bad for the whole field in general (since they provided the peer reviewers). It’s just a real double edged sword because it’s prevented me from publishing some of my work because, although the best out there, it is NOT better than what the lab previously CLAIMED to do…grr. I can easily see problems like this cropping up in other areas like climate science.
Taking that one step further, one might also surmise that the journals themselves inspire the matter. Do they not require a constant stream of submissions to their publishers in order to survive?
What would happen, say, if they faced a paucity of submissions such that they had nothing to print? Not that such would ever happen, you understand, but still …