Graphing Lesson Part 2 – "Crest to Crest"

Steve!
Thanks again for a good article.I`ve been in touch with DMI and checked the facts that was published here on WUWT from the the e-mail correspondence with them.
Its really a BIG SCANDAL that has to be monitored. The discrepancy between DMI and GISS has to be explained it can not be allowed to fade. Its just NOT acceptable.
This is without a very good explaination a PROOF of misconduct on behalf of GISS or DMI. And I can’t or will not rest until this matter is settled, neither should you.
This has to be brought to the public and authorities’ attention because this really bites!! We don’t have any FOX tv in Sweden; MSM and public service is completely WWF/Greenpeace loyal.
Has any media in the US covered this four degree gap DMI/NASA?
Swedish goverment public service is an embarrasment and just Wednesday on prime newstime they argued that floods in China were due to “climate change” and that it was hotter and worse than ever. If you are sceptic to the BBC …..well you should try the Swedish SVT!!! That’s a REAL climate propaganda center.

Maybe I got up too early this morning & am suffering from a case of the stupids, but why is the RSS trend line in the second graph different from the RSS trend line in the fourth graph?

Leon,
You are correct. The last graph is to the start of 2010, not the present. I asked the moderator to replace it with the equivalent graph
http://climateinsiders.files.wordpress.com/2010/07/trend.png
Wood for trees has a different meaning in their to: and last: fields
[Fixed. ~dbs]

If the temperature has relatively low frequency, periodic fluctuations plotting a trend line is a highly dubious exercise.

There is a deal of nonsense talked about these graphs, isn’t there ?
I mean Look at the Y-axis, what is the shift on the scale ?
It is less than a degree centigrade, sometimes much less.
Prof Lindzen has much to say about that in his CEI lecture.
Find it on my website video wall (Dr. Lindzen of MIT, disputes …… )
http://fraudulentclimate.atspace.com/

Years ago, I was warned about using peaks or troughs. For my quick ‘napkin’ climate model, I used the mid point of the warming periods to find that once the natural background warming and solar influence of 0.15C are removed, there is only 0.08 C of warming to be attributed to other causes like decreased volcanic activity and CO2 warming for the 1930 to 1990 period. — John M Reynolds

John M Reynolds
In the ice graph, I did midpoint-to-midpoint and everyone said that was wrong. They said that it needs to be peak-to-peak. Now the criticism is that I am doing peak-to-peak when I should be doing midpoint-to-midpoint. LOL
Hansen does trough to peak (which is obviously bogus) and gets it through peer-review no problem.
Just goes to show what a joke “climate science” is. It doesn’t even vaguely resemble a serious science.
“lies, damned lies, and statistics”

jmrSudbury @ 5:04 AM
Nice point, Maven of SNOLAB.
=================

Uhm,…..do overs!!!!!

Sorry _ I’ve just noticed a typo (0.02 should have been 0.20 for 1979). Please post this corrected version if possible.
Here are the rolling ten year average global temperature anomalies, (in degrees CelsiusX100), for the preceding ten years from the NASA GISS Series. Anomalies are relative to the average for 1951-1980 and should be divided by 100 to get the anomaly in degrees Celsius.
Year ten year anomaly
1979 0.20
1980 1.70
1981 5.30
1982 5.80
1983 7.00
1984 8.70
1985 9.60
1986 12.50
1987 13.80
1988 16.80
1989 17.80
1990 19.80
1991 20.70
1992 21.50
1993 20.30
1994 21.70
1995 25.00
1996 26.60
1997 28.00
1998 30.50
1999 31.80
2000 31.30
2001 32.60
2002 36.90
2003 41.00
2004 43.50
2005 46.00
2006 48.50
2007 50.20
2008 48.90
2009 50.78
[figures derived from:
http://data.giss.nasa.gov/gistemp/tabledata/GLB…
with the annual mean J-D (January-December) figures averaged over the previous ten year periods, eg the 1979 0.20 figure is the average of +3 -10 0 +14 -8 -4 -16 +13 +1 +9 derived from the J-D years 1970-1979 inclusive. ie That is the average anomaly for the 1970s]
Thus the decadal increase in average global land/ocean surface temperature reported is:
1970s to 1980s (17.80 – 0.20)/100 = 0.1760C
1980s to 1990s (31.80 – 17.80)/100 = 0.1400C
1990s to 2000s (50.78 – 31.80)/100 = 0.1898C
(I have reported the figure to 4 sig. figs. just to aid checking of arithmetic – 2 sig. figs. would be more appropriate).
Thus, Hansen’s claim that, “that there has been no reduction in the global warming trend of 0.15-0.2C/decade” is entirely supported by the NASA GISS global land/sea surface temperature series.

Both the Canadian Annual temperature departures and US Contiguous annual temperature charts actually both show a decline since 1998

So, while you guys are sorting this out, I went to woodfortrees and did the trends myself, without the offsets. I’m struck by something I don’t understand, and maybe it is just a coincidence. You’ll note, HadCrut’s variance adjusted trend from 1998 and RSS’s is nearly identical. As we’ve noted, GISS’ slope is, well, dramatic. But, UAH’s trend is the one most closely resembling GISS.(though UAH’s is still closer to HadCrut’s than GISS) But this is counter-intuitive to me. One satellite and the other a “hard” read. (RSS and HadCrut.) And then again one satellite and another “hard” read. (UAH and GISS)…..WUWT?
http://www.woodfortrees.org/plot/rss/from:1998/trend/plot/gistemp/from:1998/trend/plot/uah/from:1998/trend/plot/hadcrut3vgl/from:1998/trend

You have to consider the physical properties of the climate system. We know that ENSO is one of the major causes of interannual variability in global average temperature. On a scale of several years, any such temperature series is going to be dominated by these fluctuations, and to a lesser extent by the solar cycle. Over longer periods, these fluctuations average out, so we see more of the sustained forcings from changes in TSI, long-lived greenhouse gases, aerosols and so on. 30 years is long enough to distinguish a trend from the ‘noise’ of the interannual variability, which tends to average out to zero. Therefore Dr. Hansen is right to point out that the current global warming of 0.15 – 0.2°C per decade shows no sign of slowing down at present.

@ Kim
Ah, but guess how many years Hansen relied on for his Congressional testimony in 1988 🙂
That’s right. Just enough to establish the trend he desired.

The whole 30 year meme was an arbitrary pick because it was easier to compute then a 35 year one, well at least that is what Phil Jones says:

From: Phil Jones
To: “Parker, David (Met Office)” , Neil Plummer
Subject: RE: Fwd: Monthly CLIMATbulletins
Date: Thu Jan 6 08:54:58 2005
Cc: “Thomas C Peterson”
Neil,
Just to reiterate David’s points, I’m hoping that IPCC will stick with 1961-90.
The issue of confusing users/media with new anomalies from a
different base period is the key one in my mind. Arguments about
the 1990s being better observed than the 1960s don’t hold too much
water with me.
There is some discussion of going to 1981-2000 to help the modelling
chapters. If we do this it will be a bit of a bodge as it will be hard to do
things properly for the surface temp and precip as we’d lose loads of
stations with long records that would then have incomplete normals.
If we do we will likely achieve it by rezeroing series and maps in
an ad hoc way.
There won’t be any move by IPCC to go for 1971-2000, as it won’t
help with satellite series or the models. 1981-2000 helps with MSU
series and the much better Reanalyses and also globally-complete
SST.
20 years (1981-2000) isn’t 30 years, but the rationale for 30 years
isn’t that compelling. The original argument was for 35 years around
1900 because Bruckner found 35 cycles in some west Russian
lakes (hence periods like 1881-1915). This went to 30 as it
easier to compute.
Personally I don’t want to change the base period till after I retire !
Cheers
Phil
At 09:22 05/01/2005, Parker, David (Met Office) wrote:

http://www.eastangliaemails.com/emails.php?eid=462&filename=1105019698.txt

In response to Steve Goddard:
I’m not criticising you. I’m merely pointing out that if you have multiple periodicities in data, as apperas to be the case in temperature, forcing linear trends on a time series may be misleading. What appears to be a short term linear trend may be simply a low frequency component of cyclical change. As with many time series problems, a hypothesis about the behaviour of that data suggests appropriate analysis techniques and these may have underlying physical interpretation. If you believe that temperature is on a linear upward path, a linear model is appropriate; if you think temperature varies with a cyclical model, there are better ways of analysing such data.
While I could write to Dr Hansen, I feel that he is unlikely to take much notice of what I have to say.

Hansen Claims
“Global warming on decadal timescales is continuing without let-up … we conclude that there has been no reduction in the global warming trend of 0.15-0.2C/decade that began in the late 1970s.”
Steve Goodard asks
Is Hansen correct, or does he need some serious graphing lessons?
The honest answer is that we don’t know. If the NULL (default) hypothesis is that warming is continuing at ~0.15 deg per decade then the data would not support rejection of it. As I pointed out on another thread a decade is too short a period to draw any conclusions. Simply lengthening/shortening the period by a few months changes the sign of the UAH trend. We need at least 5 more years before any conclusions can be drawn.

That trend graph doesn’t look right to me. The labeled trends in the legend compared to what’s plotted in the graph look off. Just me?

John Finn says:
July 31, 2010 at 7:39 am
a decade is too short a period
It was warmer on earth during the Medieval Warm Period. That was ~1000 years ago.

Jean Meeus
It is not adequate for people to say “the earth is warming.”
The fact is, it is warming much slower than the climate models forecast, indicating that climate sensitivity to CO2 is much lower than alarmists have been telling politicians.

John Finn said (July 31, 2010 at 7:39 am):

…As I pointed out on another thread a decade is too short a period to draw any conclusions. Simply lengthening/shortening the period by a few months changes the sign of the UAH trend. We need at least 5 more years before any conclusions can be drawn.

Hansen’s conclusion is based on 30 years of data. Isn’t that enough?

Girma said:

IPCC’s EXAGERATION FACTOR IS 6.7 (=0.2/0.03)!

You’re taking a projection for the trend of the *next* two decades and using data from the *previous* decade to disprove it? That’s clearly absurd, even ignoring the fact that a decade of data cannot possibly show us a long-term trend. You will have to wait about 20 years before you can say anything at all about how accurate that projection was.

Jean Meeus: “He replied that this proves nothing, that there have been similar, and even longer, non-warming periods in the past (for example from 1940 to 1970), and that the general trend (since 1900) is warming.
Any comments?”
Only to say that we know that any warming from 1900 to about 1970 was not caused by green house gases.

This post seems confused on a number of points.
1. For a cyclical and regular time series, even measuring trends peak-to-peak or trough-to-trough is not meaningful. See here
2. El Niño is not a cyclical phenomenon. It is quasi-periodic. Its amplitude varies enormously. The 1997-8 one was considerably larger than the most recent one.
3. Global temperatures are not cyclical either. The instrumental record has no “trough” to measure any trend from. The late 1970s saw a clear change in climate trends – to measure something from a point of clear change cannot be described as cherry picking. In any case, for every year in the record for which you can derive a statistically significant trend from that year to the present, the trend is positive.
4. 1998 to present is too short to measure statistically significant trends, and too short for variations between datasets to be considered significant. If you are worried about outliers, you should look at a longer trend – like since the change in climate trend in the late 1970s.

A reasonable comparison is to pull-out the variability caused by the ENSO. The 1997-98 El Nino was a little bigger than the last one was. (I also take into account the AMO since it’s impact is similar to the ENSO. Today’s AMO values are very high, about the same as they were at this time in 1998).
When these are taken into account, we find GISTemp is increasing at about the same rate it has always increased at. This rate though is much lower than predicted and will only get us about half-way to the projected warming of 3.25C by 2100.
Here is GISS since Feb 1998 (adjusted for the ENSO and AMO) versus the most current prediction of the IPCC in AR4 (under the A1B CO2 scenario which seems to be very close to the trends to date).
http://a.imageshack.us/img821/8305/gisspeak1998.png
Here is nice big chart of the IPCC AR4 predictions put up by Lucia. (Even in the year 2000, their back-cast models using temperature data up to that time were too high by 0.2C or so and they would now be too high by about 0.32C).
http://rankexploits.com/musings/wp-content/uploads/2008/08/compare-to-copenhagen.jpg

Gavin’s Goalposts
Gavin Schmidt of NASA has a website called RealClimate. A couple of years ago there was a post on signs of climate change.
http://www.realclimate.org/index.php/archives/2007/12/a-barrier-to-understanding/
In the discussion thread Daniel Klein asks at #57:
OK, simply to clarify what I’ve heard from you.
(1) If 1998 is not exceeded in all global temperature indices by 2013, you’ll be worried about state of understanding
(2) In general, any year’s global temperature that is “on trend” should be exceeded within 5 years (when size of trend exceeds “weather noise”)
(3) Any ten-year period or more with no increasing trend in global average temperature is reason for worry about state of understandings
I am curious as to whether there are other simple variables that can be looked at unambiguously in terms of their behaviour over coming years that might allow for such explicit quantitative tests of understanding?
[Response: 1) yes, 2) probably, I’d need to do some checking, 3) No. There is no iron rule of climate that says that any ten year period must have a positive trend. The expectation of any particular time period depends on the forcings that are going on. If there is a big volcanic event, then the expectation is that there will be a cooling, if GHGs are increasing, then we expect a warming etc. The point of any comparison is to compare the modelled expectation with reality – right now, the modelled expectation is for trends in the range of 0.2 to 0.3 deg/decade and so that’s the target. In any other period it depends on what the forcings are. – gavin]

A little discipline is needed when filtering noisy and/or cyclic data:
1. A way to to deal with end effects is to “window” the data. This also makes point 2 dramatically apparent – current data has little influence.
2. A moving average (or other symetrical filter method) is an estimate for the actual value of the data at the centre of the averaging period, not the end. Filtered data should be time-shifted to display correctly.
Are either of these methods used on climate data?
MG

Steve,
You must be enjoying this thread immensely.
You invite readers to observe the GISS data from 1880 to 2010, note Dr. Hansen is quoted drawing significance from the period late 1970s to present, and ask your readers “Is Hansen correct, or does he need some serious graphing lessons?”.
Well, it is as obvious as the proverbial dogs balls that Dr. Hansen references a “trough to crest” period in the data. Which, as per the background context you provided, makes the critique of your analysis on an earlier thread – you used mean to mean – trivial.
Not one of the comments – particularly not one of the comments from the warming-fast side – answers your question. Most of the discussion focuses on the last 10 or 12 years. Some explores the necessary minimum period, concluding correctly that 30 years is not enough (which is true, but you were looking for a simpler observation).
So let me be the first: any information from wandering data (I avoid the term cyclical, since that term implies a regularity not present in climate data) must be crest to crest or trough to trough or mid to mid. Since we are currently at a crest in the GISS data presented above, the only acceptable periods ending in 2010 would be 1940 to 2010 or 1900 to 2010. Anything else is intellectually dishonest.

Icarus
You wrote, “You will have to wait about 20 years before you can say anything at all about how accurate that projection was.”
If you compare the global warming rate for the last four decades, you see a definite deceleration for the last period from 2000 to 2010 as shown here:
http://www.woodfortrees.org/plot/hadcrut3vgl/from:1970/to:1980/plot/hadcrut3vgl/from:1970/to:1980/trend/plot/hadcrut3vgl/from:1980/to:1990/plot/hadcrut3vgl/from:1980/to:1990/trend/plot/hadcrut3vgl/from:1990/to:2000/plot/hadcrut3vgl/from:1990/to:2000/trend/plot/hadcrut3vgl/from:2000/to:2010/plot/hadcrut3vgl/from:2000/to:2010/trend
As a resutl, IPCC’s Exageration Factor is 6.7!

@RW
Showing a 30 year trend as being strongly positive and with agreement between the various sources while the 10 year trend in the main post shows different results simply reinforces the idea that trends should be regarded with considerable suspicion as the data clearly deviates from a linear trend.
As regards using the peak or trough of the trace, surely we are interested in the way that the mean temperature varies, i.e. a zero-phase, low pass filtered version of the signal. While the smoothing using a rectangular average creates something nearer to an integral of trace, it is not ideal for many reasons. There is substantial theory underpinning near-optimal filters. When these are constructed auto-regressively, much more useful responses can be obtained withough having to employ long impulse responses as in the case of a moving average filter so that there isn’t a “dead zone” at the beginning and end of the record.

The now common practice of extrapolating “trends” into the distant future is as unscientific as unscientific can become. My college professors in chemistry and physics all discussed this matter with their students, and each and all said, “Never do it”.
Of course, that was back in the 1950s. Wise college professors back then.

” Icarus says:
July 31, 2010 at 11:16 am
…variability is ~0.2C from year to year, and the trend is ~0.2C per decade. In other words, interannual variability can completely mask the long term trend in any 10 year period. Make sense?”
What does not make sense is the fact that Hansen observes the trend of 0.2°C per decade (for 1998 to 2009), whereas Jones or Spencer do not.

Bart: El Niño is not periodic. It is quasi-periodic, occurring at intervals typically of 2-7 years.
RC Saumarez: “trends should be regarded with considerable suspicion as the data clearly deviates from a linear trend” – well, certainly the trend may not be linear, but we could avoid all sorts of misinterpretation problems if no trend was ever plotted without the ±1σ trend lines also marked.

When I look at the long term HADCRUT and superimpose a linear trend on that, it shows a 0.7 rise over the 160 years. However that is with 3 peaks and 2 troughs of a lumpy sine wave, which correlates very closely with the PDO cycles, and could be said to be entirely attributable to natural variation.
There is every indication that we are past the beginning of a cool cycle, and if the past is any guide to the future, it is likely that we will finish this cool cycle about 0.7C below where we are now. That will drag the linear trend down to about a 0.6C rise over 180 years.
Given we were coming out of a little ice age, I don’t think there’s anything here to be getting alarmed about. In fact, what’s strange about all this, is just how stable the climate has been when you consider all of the factors that contribute to climate change.
Further, it is only this 0.6C rise that we can attribute anything not natural to, such as greenhouse gasses or other forcings, and that is assuming that this 180yr trend isn’t just part of a longer cycle, possibly headed down again given our weak sun.
Dr Lindzen was right. Our descendants are going to have a good old laugh at our version of arguing over angels on pins.

RW says:
July 31, 2010 at 8:45 am
“1. For a cyclical and regular time series, even measuring trends peak-to-peak or trough-to-trough is not meaningful. See here”
It certainly is. The trend is mathematically zero. I don’t know what the woodfortrees plotter thinks it’s doing, but what it isn’t doing is calculating a linear trend over the test dataset. I hope people haven’t been using it on real data, because it’s giving nonsensical answers. The programme seems to have a serious bug in it.

What utter nonsense ! A hadcrut3 “trend” of 0.02 degrees in 10 years ? Where are the error bands ?
Surfacestations.org found errors of greater that 1 degree for over 90% of stations !! This is a factor of at least 50 greater, making any such trends meaningless. Even the recording accuracy is still listed as 1 degree. ( http://www.srh.noaa.gov/ohx/dad/coop/EQUIPMENT.pdf page 11 )
What difference does it make if the world is warming or cooling anyway ? The issue is whether man has had anything to do with it … something the IPCC and alarmists have no evidence whatsoever to support.

Jean Meeus, we have two generally accepted definitions of climate change circulating. They are not the same. I discuss this in my essay “Climate Change, Just What Is That Anyway?”. To sum: “…. From Wikipedia:
“For current global climate change, see Global warming.
For past climate change, see paleoclimatology and geologic temperature record.
Climate change is a change in the statistical distribution of weather over periods of time that range from decades to millions of years. It can be a change in the average weather or a change in the distribution of weather events around an average (for example, greater or fewer extreme weather events). Climate change may be limited to a specific region, or may occur across the whole Earth.” Now I can live with that as it meets all the needs of my science and I suspect others. I am sure it was written by someone knowledgeable in the scientific method and the Philosophy of Science. However, the Wikipedia authors go on to say:
“In recent usage, especially in the context of environmental policy, climate change usually refers to changes in modern climate. It may be qualified as anthropogenic climate change, more generally known as “global warming” or “anthropogenic global warming” (AGW).” I guess that explains my wondering. It is clear that two different definitions are in use. This is not good. It is very much not good, because it tends to cause confusion….”

@Paul Birch.
What are you saying? If sucessive peaks are identical but the shape of a curve deviates from being a pure sinusoid, so that the integral of the sucessive curves wrt time is increased, this has no meaning – “the trend is zero”?
This whole argument would benefit from a rather more rigorous definition of how temperature is defined as a function of time and the application of a mathematical model that recognises the complexities of the data. Fitting least squares line to a continuous signal that does not have a defined distribution is difficult to interpret and (@RW) since the distribution of the data is non-stationary, calculation of exact confidence limits is problematic.

Wow, I’m on a roll.
I must ask for opinions here. Mine is that the [snip] in the AGW cult have had a small victory of sorts by being able to draw everyone on the Skeptics side into short termism. ie. Last 10 years have been hottest since Marilyn Monroe…etc.
The claim by the cultists has to be seen in the context of the length of the Industrial Revolution. We should, I think walk away from the short termism and start hammering away at the reality of climate. It cycles. And since the 1840-50s the ‘warming’ has been statistically insignificant within those cycles. The claim of unprecedented warming and a tipping point are like ‘Jesus walked on water and heaven is full of virgins’ . The stuff of fanaticism & Emotional Terrorism.
The 1850 s are a nice central starting point as the American East was full of industry, Europe as well, so that awful CO2 was being produced in an ‘unprecedented’ amount.
waddayarekon??? Long term or short term ??
regards from a cold, wet Southern Oz.

I think I see part of the problem. It looks as if when the trend is zero it fails to draw the red line at all. You have to add a little bit to the end time. Btw, by “cyclical and regular” I understand symmetrical about the peaks or troughs. The trend is not necessarily zero for an asymmetrical periodic function, nor between points other than extrema on a symmetric function.

Icarus says:
July 31, 2010 at 2:18 pm
…….”I do think Spencer tries hard to minimise the warming in his data series.”
==
Any other opinions, you care to share with us?

Icarus,
Amazingly bad luck for the human race that the satellites came on line in 1979.
http://climateinsiders.files.wordpress.com/2010/07/fig-a2-lrg2.gif
This has given Hansen cover for his cherry-picked trend.

stevengoddard says:
July 31, 2010 at 5:14 pm
Amazingly bad luck for the human race that the satellites came on line in 1979…
This has given Hansen cover for his cherry-picked trend.
______________________________________________________-
You have that correct Steve. If the satellites had come on line in 1929 we would have seen the sine wave pattern due to the ocean oscillations instead of a linear approximation of one side of the curve.
Here is what I mean typical graph of an east coast city

Icarus says:
July 31, 2010 at 2:45 pm
paulhan said (July 31, 2010 at 1:35 pm):
When I look at the long term HADCRUT and superimpose a linear trend on that, it shows a 0.7 rise over the 160 years.
What does that tell us? Not very much, considering that important forcings over that period, such as TSI and well-mixed greenhouse gases, are not changing linearly.

It tells us that in 160 years, when CO2 increased by 35%, when we have most of a cooling phase still to come, when we have data collectors trying to wring every last tenth of a degree warming out of the dataset, when the human population went from 1.2 billion to 6.7 billion, when those same humans enjoyed an unparallelled increase in both life expectancy and quality of life, that the best case scenario from a warmist’s point of view, is that temperatures will have gone up by 0.6C in 180yrs, and that that includes any subsequent forcings caused by the increase in CO2. It tells us that you need to get another bogeyman, because CO2 isn’t it.

However that is with 3 peaks and 2 troughs of a lumpy sine wave, which correlates very closely with the PDO cycles, and could be said to be entirely attributable to natural variation.
The great increase in atmospheric CO2 over that period is not a natural variation.

And surely that tells you that CO2 cannot cause the catastrophic climate change that you and people like you keep telling us is going to pass.

There is every indication that we are past the beginning of a cool cycle…
What indication is there of that?

There is the indication that temperatures haven’t risen in a statistically significant way in 15yrs, and that’s straight from Phil Jones. Will that do?

Given we were coming out of a little ice age, I don’t think there’s anything here to be getting alarmed about.
What forcing, precisely, is responsible for us ‘coming out of a little ice age’? Please support this assertion with data.

You tell me!!

Further, it is only this 0.6C rise that we can attribute anything not natural to, such as greenhouse gasses or other forcings, and that is assuming that this 180yr trend isn’t just part of a longer cycle, possibly headed down again given our weak sun.
Dr Lindzen was right. Our descendants are going to have a good old laugh at our version of arguing over angels on pins.
The trouble is, there is around another 0.4 to 0.5C of warming in the pipeline due to the lag in ocean warming, just from ~390ppm of CO2, which takes us to 1.2C above pre-industrial. Then we have to consider how much higher atmospheric CO2 is going to rise – no-one seriously thinks that it’s going to stop rising anytime soon, so there will definitely be more warming on top of that 1.2C. Then also, we risk more warming still from any decline in anthropogenic aerosols (e.g. if industry in China cleans up its pollution). Considering the rapid decline of Arctic ice and glaciers and so on even at current warming, I don’t think our descendents are going to be laughing about our actions. Condemning us, perhaps.

Ocean temps haven’t gone any higher than 1998 either, so that’s just speculation on your part. To be fair, my predictions are also speculation. But if the past 160yrs is anything to go by, then I think my predictions have a better chance of coming to pass. And we certainly shouldn’t be taking any drastic actions until at least this cool phase plays out.

Icarus says:
…The great increase in atmospheric CO2 over that period is not a natural variation…
…What forcing, precisely, is responsible for us ‘coming out of a little ice age’? Please support this assertion with data…
What amount of the current warming trend comes from natural variation, and what are the components of that variation? What amount of the current warming trend comes from CO2?

Icarus says:
…Then also, we risk more warming still from any decline in anthropogenic aerosols (e.g. if industry in China cleans up its pollution). Considering the rapid decline of Arctic ice and glaciers and so on even at current warming, I don’t think our descendents are going to be laughing about our actions. Condemning us, perhaps…
Chinese kids with cleaner air? Not exactly comical, but hardly condemnable.

Icarus says:
July 31, 2010 at 2:45 pm
……
The trouble is, there is around another 0.4 to 0.5C of warming in the pipeline due to the lag in ocean warming, just from ~390ppm of CO2, which takes us to 1.2C above pre-industrial.
But is there more in the pipeline? It’s looking increasingly likely that most of the heating from CO2 forcing to date has been realised. This is this “missing heat” that Trenberth was looking for. It’s simply not there.

Spector: Are you arguing that the anthropogenic enhanced greenhouse effect is dwarfed by some other, natural forcing? If so, what, and by how much?

John Finn: There is currently a net energy imbalance of ~0.5W/m². That’s where the warming ‘in the pipeline’ comes from. It will take at least a couple of decades for that to equilibrate (and by then atmospheric CO2 is likely to be considerably higher, of course).

Paul Birch – actually I’m almost certain the woodfortrees code doesn’t have a bug, at least not in its linear fitting routine. Mathematically, the average of a sine curve over one cycle is zero, but if you sum up the squares of the residuals from the lines you see on the woodfortrees plot, and from the origin, you’ll see that the lines with gradients are “better” fits. This just shows that linear least squares regression isn’t a good way to understand what a sine curve is doing. Using gnuplot I found that for one cycle of a sine curve represented by y=sin(x*pi/32), the “best” fit had the equation y=-0.0283321x + 0.936467. The RMS residual for this fit was 0.444361; the RMS residual from the origin was 0.707107, the square root of 0.5.

Icarus says:
August 1, 2010 at 2:20 am
John Finn: There is currently a net energy imbalance of ~0.5W/m². That’s where the warming ‘in the pipeline’ comes from. It will take at least a couple of decades for that to equilibrate (and by then atmospheric CO2 is likely to be considerably higher, of course).
I’m not sure there is any evidence of this imbalance. This is the problem Kevin Trenberth was confronted with. They either can’t find the missing energy or can’t find “the pipeline”. Can you shed any light on its whereabouts?

When I look at the 600,000 year graph of temperatures, two things stand out:
1. We are presently near the top of a warming trend, and the next major move is likely to be sharply downward;
2. We have had a relatively constant climate for the past 10,000, something that seems to be unprecedented in the last 600,000. What has caused this relative stability?
I wish that something as simple as adding CO2 to the atmosphere could stave off the next ice age, but I just don’t think that is the case.

” Icarus says:
July 31, 2010 at 2:18 pm
‘Alexej Buergin said (July 31, 2010 at 11:46 am):
What does not make sense is the fact that Hansen observes the trend of 0.2°C per decade (for 1998 to 2009), whereas Jones or Spencer do not.’
Spencer’s MSU UAH shows 0.14C per decade over the full data set.
RSS is 0.16C per decade.
GISTEMP is 0.17C per decade.
HADCRUT3 is 0.16C per decade.”
O! say can you see that I have written something in brackets? It says there 1998 to 2010. Your “rebuttal” is about the full data set. So you are trying to fly too high.
As Phil Jones said: There was no significant warming during the last 15 years.

Alexej Buergin: Why do you prefer the 1998 – 2010 data rather than the whole data set?

Larry said (August 1, 2010 at 6:16 am):

I wish that something as simple as adding CO2 to the atmosphere could stave off the next ice age, but I just don’t think that is the case.

Why not? The palaeoclimate data suggests that millions of years ago the Earth was permanently ice-free with the sun being cooler than it is now, the difference being due to the higher atmospheric CO2 that prevailed then. If we achieve the same situation in the future that nature did in the past, wouldn’t it be reasonable to expect the same consequences? If not, why not?

RE: Icarus: (August 1, 2010 at 2:13 am) “Spector: Are you arguing that the anthropogenic enhanced greenhouse effect is dwarfed by some other, natural forcing? If so, what, and by how much?
It is well known that there is a maximum stable adiabatic lapse rate linking surface temperatures to the temperature of the tropopause. Every time we have a convection event, nature’s natural air-conditioner has just kicked in. Depending on the situation, this can be violent or gentle.
So far, I have not seen anyone attempt to explain what happened to this natural temperature regulation system in the transition from the Medieval Warm Period to the Little Ice Age. Perhaps something forced the tropopause to a lower altitude and this drove colder temperatures to the surface or perhaps something caused a general cooling of the tropopause level and this was reflected to the surface via the required stable lapse rate.
It appears to me that much of the discussion so far has been focused on surface heating effects with little regard for the fact that surface cannot warm unless the tropopause warms likewise or the rises to a higher level. As the concentration of gaseous water (water ‘vapor’) in the atmosphere is about 100 times that of CO2, I would think that the behavior this gas would be the most important in determining the tropopause level. I have not found any historical year-by-year tropopause temperature and altitude data provided anywhere online.
Another important point is the fact, pointed out by Dr. Spencer, that the tropopause is the level where Earthshine absorbing and emitting (greenhouse) gases primarily serve to cool rather than heat the atmosphere.

stength = stench+strength

Richard M said (August 1, 2010 at 8:55 am):

Icarus, please show exactly where that pipeline enrgy is hiding. Be specific.

It’s in the current global energy imbalance (i.e. radiative energy received from the sun exceeds that radiated back to space from the Earth). That will take some decades to equilibrate, even if CO2 doesn’t rise any more (which is extremely unlikely).

Talk about cherry-picking! Look at his start point. He chose the worst case trough to crest to measure his trend.

There is no oscillation in the temperature record in 30-year periods. There is no even remotely recognizable ‘peak and trough’ in the instrumental record on decadal scales. One could argue there is an oscillation in the data (PDO), but it does not account for the long-term trend. There is year by year oscillation in the temp record – global temps tend to be warmer during Northern Hemispheric summer – but Hansen took annual averages, and did not, nor could not, make the same mistake Goddard did on sea ice data.
Hansen’s 30-year trend (of temperature) is far more statistically significant than a 9 year trend (of Arctic sea ice). How soon we forget that statistical significance tests fail for global temperature starting if we start from 1995 to 2009 – 15 years (if you’re reading this post in 2011, that may no longer be the case). That factoid was made much of at Watts Up With That, but it seems to stop no one here from prognosticating on climate trends with much shorter time periods. This lack of consistency hardly inspires confidence.
(Aside: sea ice trends probably don’t need as many years as climate trends to achieve statistical significance, but 9 years is statistically insignificant for either metric)
While we’re on the subject of cherry-picking, I ran the regression function on sea ice data at wood for trees, matching the (erroneous) method used by Steve Goddard, who runs the plot from mid-2002 to present. From mid-2001 to present, there was a shallower upwards trend. From mid-2000 to present, a flat trend. Every year back thereafter (starting at 2000, then 1999, 1998 etc), the trend to present was of reduced sea ice. Selecting 2002 as a start point is cherry-picking – or in the words much expressed at WUWT re Jones and temp trends since 1995, it’s not ‘significant’.
There are sound reasons to compute global temps for the last 30 years – can cross-check with satellite record and with sea ice record, solar output has been flat or slightly waning in that period, the flat or cooling mid-century temps may have been a product of aerosols from industry (cleaned up since then by regulations on emissions), and the time period is statistically robust. Readers could be led to believe, however, that Jim Hansen doesn’t talk about pre-70s global temperature. That’s just wrong.
(I could be wrong, but I think the first link in the article goes to the wrong WUWT page. Shouldn’t it be: http://wattsupwiththat.com/2010/07/02/arctic-ice-increasing-by-50000-km2-per-year)

The title of Goddard’s contribution is “crest to crest”. Most people agree that this is the best (or least bad) way to calculate a trend. February (maybe April) of the El Niño-year 1998 is the first peak, and March (maybe July) of the El Niño-2010 is the second one (UAH). So copy the monthly UAH-data into an Excel file, let it calculate the trend, then you get an indication of the warming during the last decade (or 12 years), and nobody can accuse you of cherry-picking.
Phil Jones must have used CRUtemp, of course, when he says there was no significant warning during the last 15 years.

Just to correct/clarify the use of “last” on WFT here. “last:N” takes the last N samples from the current date – so for example, last:120 gives the last ten years data measured from the time the viewer fetches the graph (not the time you first made it!). The combination of “from” and “last” doesn’t make sense, and actually only works because 2010 is a huge number of samples so doesn’t limit the interval already set.
I think Steven meant to use “to:2010” in the initial graphs, which would fix the end-point even if the graph was re-viewed in 2011, 2020 or whatever. Remember that WFT uses decimal years and does not include the ‘to’ end-point: technically left-closed, right-open = [from,to). So “to:2010” gives December 2009 as the last sample. That means if you do from:2000/to:2010 you get the expected 120 samples.
Icarus/Paul Birch: The OLS C++ code is available on the site – if you think there is a real problem there please contact me privately.
Cheers
Paul

” Icarus says:
August 1, 2010 at 9:25 am
Alexej Buergin: Why do you prefer the 1998 – 2010 data rather than the whole data set?”
This is what I tried to answer at 2:15 a.m.

Phil Jones must have used CRUtemp, of course, when he says there was no significant warning during the last 15 years.

That’s not what he said, that is what the press and skeptical blogsites erroneously reported he said.
He said that the warming between 1995 and 2009 was not statistically significant. A lot of people didn’t understand what that qualifier meant – basically that the confidence level of the trend was slightly less than 95%. It’s a warming trend, but there is a non-negligible chance that the trend could be zero.
By the end of the year, the temperatures since 1995 will have statistical significance. Then some eejit will say, “there has been no significant warming since 1996,” again confusing a statistical term with its common usage.

woodfortrees (Paul Clark) :
I hadn’t realised that the datapoints were monthly (though now you mention it, that makes sense). This makes the decimal data entry rather messy. I wonder if it might be better to use months there, ie., 1900.0 (December 1899) to 1900.11 (November 1900). Then I would suggest using the end dates inclusively, but weighting the end samples so that there are still 12 samples a year. Thus 1900.0 – 1910.0 would give only half weight to the 1900.0 and 1910.0 samples, full weight to the rest. Whereas 1900.05 – 1910.05 (in base 12 method) would give zero weight to 1900.0 and 1910.1, but full weight to 1900.1 and 1910.0 (and everything between).
Whatever you decide, I think you need to show clearly, somewhere on the working page, what conventions you’re using – and warn users about any traps they’re likely to fall into. You may already do that somewhere on site, but I couldn’t find it.

” barry says:
August 2, 2010 at 8:25 am
He said that the warming between 1995 and 2009 was not statistically significant. A lot of people didn’t understand what that qualifier meant – basically that the confidence level of the trend was slightly less than 95%. It’s a warming trend, but there is a non-negligible chance that the trend could be zero.”
A sociologist, a physicist and a mathematician went to France and saw a black sheep.
Sociologist: “The sheep in France are black”.
Physicist: “There is a black sheep in France”.
Barry the mathematician: “There is at least one sheep in France, which is black on at least one side”.

Alexej, I have no ideas what your analogy is supposed to mean, but here is the trend 1995 – 2009 based on HadCRUt.
http://www.woodfortrees.org/plot/hadcrut3vgl/from:1995/plot/hadcrut3vgl/from:1995/to:2010/trend
About 0.1C per decade, a stronger warming trend than the 20th century. In common terms, that is ‘significant’.
In mathematical terms, the time period just fails statistical significance – the confidence level for this plot is slightly less than 95%. That is what Jones was saying. By 2011, the trend from 1995 will achieve statistical significance, and unless there is a huge plummet in temps for the rest of this year, the trend will have increased a bit.
12 years is way too short to achieve statistical significance with respect to global temperature trends.

” barry says:
August 2, 2010 at 12:18 pm
Alexej, I have no ideas what your analogy is supposed to mean”
It means that most people here know what “statistically significant” means, so you do not have to recite the whole definition every time. And that mathematicians are complicated people by nature.
And Goddard’s point is that one should start in 1998 (crest), not in 1995, anyway.

Icarus says:
July 31, 2010 at 2:45 pm
……
The trouble is, there is around another 0.4 to 0.5C of warming in the pipeline due to the lag in ocean warming, just from ~390ppm of CO2, which takes us to 1.2C above pre-industrial.
……
The amount of unrealized temperature gain can be modeled as a bank account. We are depositing carbon forcings (delta ln(co2)) and nature is withdrawing from this unrealized account and transferring it to the realized account.
This model is known in financial terms as the accumulated value of a continuously compounding annuity with continuous payments. The accumulated value factor is: (exp(RT)-1)/R, where R is a rate (negative in this case) and T is time.
Now because R is negative, as T goes to infinity, the exp(RT) term goes to 0 and the accumulated value converges to -1/R.
To estimate R, I calculated that there is about an 80 day lag in SST’s from seasonal solar forcings. I’ll skip the math, but this gives R=-1.23 on a yearly basis. This means that there can be no more than .83 years worth of carbon deposits left in the unrealized temperature gain account. In effect, all co2 deposits up to last year have been fully realized and this would leave only one or two hundredths of a degree in the pipeline.
BTW, I’m not just making this up. The exp(RT) term was used by none other than Sir Issac Newton himself in his “Law of Cooling” and has been confirmed by countless small scale experiments. Does this scale up to the global level? Not sure, but I haven’t seen anything that refutes it. The .4 to .5C that you quote probably comes from the complicated computations hidden in the climate models.
Also, I have done the same exercise assuming a more realistic linearly increasing deposit rate, and the conclusion is the same. The amount in the pipeline converges to a very small amount. That is probably why Trenberth can’t find it.
HTH,
AJ

It’s worth noting that el Nino periods are not symmetrically cyclical as is the case with annual fluctuations of sea ice cover. El Nino cycles are 5 years on average, but peak to peak can be as short as 2 years and as long as 7 years. Sea ice cover increases and decreases on a monotonous 1-year cycle, winter and summer.
El Nino periods themselves are not symmetrical in their duration. They also can peak at any month in the year, although they tend to be centred on the beginning/end of the years.
In order to discern an underlying trend from noisy, near-chaotic data, you need to work with a long enough time period where the noise is canceled out. 12 years is not enough.
One of these days, a competent statistician may work the sums for us, and deliver the statistical confidence value for the period 1998 – to present (August 2010). There are skeptical contributors to this website with the skill to do that, but for reasons unexplained, they never do (AFAIK).