Guest essay by Bob Tisdale | Judith Curry and Gavin Schmidt are arguing once again about how much of the global warming we’ve experienced since 1950 is attributable to human-induced global warming. Judith’s argument was presented in her post The 50-50 argument at ClimateEtc (where this morning there were more than 700 comments…wow…so that thread may take a few moments to download.) Gavin’s response can be found at the RealClimate post IPCC attribution statements redux: A response to Judith Curry.
Gavin’s first illustration is described by the caption:
The probability density function for the fraction of warming attributable to human activity (derived from Fig. 10.5 in IPCC AR5). The bulk of the probability is far to the right of the “50%” line, and the peak is around 110%.
I’ve included Gavin’s illustration as my Figure 1.
Figure 1
So the discussion is about the warming rate of global surface temperature anomalies since 1950. Figure 2 presents the global GISS Land-Ocean Temperature Index data for the period of 1950 to 2013. I’m using the GISS data because Gavin was newly promoted to the head of GISS. (BTW, congrats, Gavin.) As illustrated, the global warming rate from 1950 to 2013 is 0.12 deg C/decade, according to the GISS data.
Figure 2
For this discussion, let’s overlook the two hiatus periods during the term of 1950 to 2013…whether they were caused by aerosols or naturally occurring multidecadal variations in known coupled ocean-atmosphere processes, such as the Atlantic Multidecadal Oscillation (AMO) and the dominance of El Niño or La Niña events (ENSO). Let’s also overlook for this discussion any arguments about how much of the warming from the mid-1970s to the turn of the century was caused by manmade greenhouse gases or the naturally occurring multidecadal variations in the AMO and ENSO.
Bottom line, according to Gavin:
The bottom line is that multiple studies indicate with very strong confidence that human activity is the dominant component in the warming of the last 50 to 60 years, and that our best estimates are that pretty much all of the rise is anthropogenic.
Or in other words, all the warming of global surfaces from 1950 to 2013 is caused by anthropogenic sources. Curiously, that’s only a warming rate of +0.12 deg C/decade. He’s not saying that all of the warming, at a higher rate, from the mid-1970s to the turn of the century is anthropogenic. His focus is the period starting in 1950 with the lower warming rate.
HOWEVER
Climate models are not tuned to the period starting in 1950. They are tuned to a cherry-picked period with a much higher warming rate…the period of 1976-2005 according to Mauritsen, et al. (2012) Tuning the Climate of a Global Model [paywalled]. A preprint edition is here. As shown in Figure 3, the period of 1976 to 2005 has a much higher warming rate, about +0.19 deg C/decade. And that’s the starting trend for the long-term projections, not the lower, longer-term trend.
Figure 3
And that’s why, when compared to the observed warming rate for the period of 1950 to 2013, which, according to Gavin, is the period “that our best estimates are that pretty much all of the rise is anthropogenic”, then climate model warming rates appear to go off on a tangent. The modelers have started their projections from a cherry-picked period with a high warming rate.
Figure 4 shows the warming rates for multi-model ensemble-member mean of the CMIP5-archived models using RCP6.0 and RCP8.5 scenarios for the period of 2001-2030. RCP6.0 basically has the same warming rate as the observations from 1976-2005, which is the model tuning period, but that’s much higher than the warming rate from 1950-2013. And the trend of the business-as-usual RCP8.5 scenario seems to be skyrocketing off with no basis in reality.
Figure 4
And in Figure 5, the modeled warming rates for the same scenarios are shown through 2100.
Figure 5
CLOSING
I’ve asked a similar question before: Why would the climate modelers base their projections of global warming on the trends of a cherry-picked period with a high warming rate? The models being out of phase with the longer-term trends exaggerates the doom-and-gloom scenarios, of course.
But we purposely overlooked a couple of things in this post…that there are, in fact, naturally occurring ocean-atmosphere processes that contributed to the warming from the mid-1970s to the turn of the century—ENSO and the AMO. The climate models are not only out of phase with the long-term data, they are out of touch with reality.
SOURCES
The GISS Land-Ocean Temperature Index data are available here, and the CMIP5 climate model outputs are available through the KNMI Climate Explorer, specifically the Monthly CMIP5 scenario runs webpage.
Since the 110% is getting people confused, let me explain a little bit. The 110% is the theoretical AGW (the warming that–according to the IPCC and Gavin–would have occurred if there were no natural cooling influence) divided by the real warming that was actually measured. I discussed this in the guest post I mentioned earlier.
http://judithcurry.com/2014/01/29/the-big-question/
It’s not just counterintuitive, it also has some insane consequences. The longer the pause lasts, the more certain the AGW dominance becomes. The catch is that it’s an ever slower rate of warming, and therefore you have to expect slower waming in the future anyway. It’s pretty misleading, but I think Gavin is so steeped in this mode of thinking, he actually believes it’s the right way to calculate.
Remember the research is already years old. I am sure if the numbers are run today the most likely percent of AGW would now be 140%, and extremely likely more than 75% is AGW. Like you say, the longer the pause the more certain the temperature rise is AGW! If the temperature falls the next 5 years, look out, certainty will sky rocket even higher that CAGW is coming!
So that 110%, -150% or 250% “probabilities” are actually something like slope, or differences, which are added and subtracted? In that case they aren’t probabilities, of course. If I got your interesting post.
That’s correct. Those aren’t probabilities. The probability is the notorious 95% and the statistical method practically guarantees that it will increase.
They’re introducing too many epicycles by now.
Folks here are confusing effect with probability.
Probability of an occurrence can never exceed 1.0.
Effects can cancel out other effects, and thus individually contribute more than 100% of an observed integrated output such as global temp reponse.
The rate remains defiantly linear in nearly all of the oldest real thermometer records, despite both urban heating effects and the overall greenhouse effect plus or minus feedbacks:
http://s6.postimg.org/uv8srv94h/id_AOo_E.gif
The same exact thing is seen in nearly every long running tide gaude record.
So indeed, 110% needs be invoked since an unprecedented cooling spell has to be have been averted for a mere trend continuation to be blamed on emissions. It’s amazing how the ghost of debunked hockey sticks live on as a background assumption to conceal these old records that debunk anthropogenic claims quite strongly as far as traditional scientific rigor is concerned.
so how do you account for the change in recording
from mercury thermometers (not re-calibrated before 1950) and human observation (usually 4 times per day) with thermo couples and measuring records of every second a day?
NikFromNYC August 28, 2014 at 12:37 pm
Do you data on the trend lines, assuming a linear function
Scrub the above …
Do you have data on the trend lines, assuming a linear function for the full record and ,say, for 1900 onward?
Yeah, been watching and commenting at JC’s site on this. Fascinating, as is Bob’s response here.
Once again, my apologies if anyone is offended by this, but this remains in my mind like “two fleas arguing over who owns the dog they are riding on” (Crocodile Dundee).
It begs sanity, IMHO, that we are even having this discussion at all.
There are only 2 possibilities here. That’s it!
1 The Holocene would just have continued blithely along, presumably forever were it not for Anthropogenic disturbances, AGW etc.
2. The AGW hypothesis is correct which makes Ruddiman’s Early Anthropogenic Hypothesis also correct. The Holocene may well be over and we are living in the Anthropocene now. Interglacial conditions extended by AGW.
On possibility 1, here is my detailed look at the Holocene conundrum http://wattsupwiththat.com/2012/03/16/the-end-holocene-or-how-to-make-out-like-a-madoff-climate-change-insurer/
On possibility 2. we find ourselves faced with perhaps ending the Anthropocene by stripping the CO2/GHG “climate security blanket” from the atmosphere. If the AGW hypothesis is correct, that would leave glacial inception as the only other climate state, wouldn’t it?
The Pretzel Logic here is simply gobsmacking!!
You cannot be right about the “Anthropocene”, or ending it, without getting a hated tipping point, but of the opposite sign to the one expected. If CO2/GHGs are holding us in interglacial conditions, wouldn’t removing the excess tip us into the next glacial inception?
Getting deep into the Judith/Gavin weeds is, of course, a very interesting discussion. “I suggest a new strategy R2, let the Wookie win!”, C3PO. Because the real fun begins if cede Gavin is right, because the choice is really about extending the Holocene, or removing the “climate security blanket” so we can get on with our overdue glacial inception.
Muller and Pross (2007) provide one of the more poignant quotes in all of climate science:
“The possible explanation as to why we are still in an interglacial relates to the early anthropogenic hypothesis of Ruddiman (2003, 2005). According to that hypothesis, the anomalous increase of CO2 and CH4 concentrations in the atmosphere as observed in mid- to late Holocene ice-cores results from anthropogenic deforestation and rice irrigation, which started in the early Neolithic at 8000 and 5000 yr BP, respectively. Ruddiman proposes that these early human greenhouse gas emissions prevented the inception of an overdue glacial that otherwise would have already started.”
http://folk.uib.no/abo007/share/papers/eemian_and_lgi/mueller_pross07.qsr.pdf
you did not get it
at all
http://wattsupwiththat.com/2014/08/28/a-note-on-the-50-50-attribution-argument-between-judith-curry-and-gavin-schmidt/#comment-1721017
You are correct. I’m not following you at all.
OK, so let me take a stab at responding.
“you did not get it at all” provides only an ad hominem. The comment link, on the other hand provides what I think is enough information to suggest that your point is there is no anthropogenic influence.
Stepping out on that limb is putting forth a hypothesis. I do not disagree with your hypothesis. However, one of the key steps one takes as a scientist when thinking about proposing their hypothesis is to adopt the opposing position(s) as a means of testing the hypothesis. Standard science.
So adopting the opposing viewpoint, standard in science, is that there is a decisive climate impact from CO2/GHGs. And if that was correct, then we are living in the Anthropocene extension of the Holocene interglacial. So, with our standard science adopted opposite viewpoint, we now come to what do if we are right? Strip CO2/GHGs from the Anthropocene atmosphere, and where does THAT leave us?
The only other state would be getting on with that overdue glacial inception.
I am in no way saying you are wrong. I am saying what if you are wrong and the AGW crowd is right? Would not being right about AGW, and quelling its atmospheric presence, actually be the wrong thing to do?
Except under Ruddiman, the Holocene would scarcely have been an interglacial at all. The Eemian lasted 16,000 years & the MIS 11 interglacial tens of thousands. Those of MIS 7 & 9 were longer than the Holocene would have been under Ruddiman’s hypothesis.
Milodon, I would suggest that instead of just taking a higher-end estimate for the length of the Eemian, which of course is a length quoted by several authors, it is by no means the consensus on the length of the Eemian. There probably isn’t one, but the range would seem to be somewhere between 10-13kyrs with 16 being an outlier, but not the furthest outlier. I do not have the time to dig all of this up anytime soon, but there is still disagreement as to whether Termination II was a single step, or a two-step one like Termination I. From memory, it seems like evidence for a 2-step deglaciation into the Eemian seems more likely as higher resolution studies pile-up. From memory again, the 135kyr start of the Eemian tends to be associated with the single warming camp. The 2-step camp, from memory counts the period from 135kyrs to 125kyrs as consisting of two warming events with a duration for both similar to the last deglaciation. ~115kyrs ago is what I remember as being one of the more frequent conclusions as to when the Eemian ran down. So something on the order of 10-20kyrs, depending on who you quote and depending on whether the 10kyr deglaciation interval is included in the estimate.
I took a quick look in my Eemian folder and was rewarded with this 2008 paper http://journals.co-action.net/index.php/polar/article/download/6172/6851 Have a look at Figure 5 and you will catch my drift.
This is not about tit for tat, because even on things which have happened, the science is not particularly well-settled. Which makes consideration of the science being settled on something which has not happened yet a bit unsettling…. 🙂
My bad! I meant Figure 6 (dang keyboard)
That is a fascinating argument!
It is, isn’t it?
And it took no time at all to realize I was decidedly not the only one who had come of such an argument. This simply cannot be had both ways. AGW either can (and may already have) extended the Holocene, or it cannot. That’s pretty much it.
The most thorough analysis is still Tzedakis 2010 landmark paper here http://www.clim-past.net/6/131/2010/cp-6-131-2010.pdf
If anthropogenic effect in global warming in the modern times is more than 1% in total, I would be impressed.
it is exactly 0.000K/annum
http://wattsupwiththat.com/2014/08/28/a-note-on-the-50-50-attribution-argument-between-judith-curry-and-gavin-schmidt/#comment-1721017
How could any blog generate +700 argumentative comments to a article on the 97% consensus, with 110% attribution to humans, ‘settled science’ of man made global warming??? It seems highly improbable, unless the ‘science’ is ill supported. And the proponent of the ‘110% attribution’ does not respond directly to the blog article on ClimateEtc, choosing to fire his blunderbuss from behind the self censured revetments of RealClimate, ala Kim Jong Un? (There is a bit of a resemblance….)
Settled science doesn’t draw such spirited discussion. Unsettled science does, as does unsupported conjecture or willful deceit.
Outstanding observation. That Gavin felt compelled to rebut Judith is the big news. Downright unsettling…
Struth.
You only have to take a sample of weather stations to see what’s happening
http://blogs.24.com/henryp/2013/02/21/henrys-pool-tables-on-global-warmingcooling/
WRONG
the models are not tuned to the period this ONE PAPER reports for ONE model.
Even here you get it wrong
“Formulating and prioritizing our goals is challenging. To us, a global mean temperature
in close absolute agreement with observations is of highest priority because it sets the
stage for temperature-dependent processes to act. For this, we target the 1850-1880
observed global mean temperature of about 13.7◦C
[Brohan et al., 2006].
Finally. But you’re wrong too. One model, one paper. And you left out the most important part.
Arguably, the most basic physical property that we expect global climate models to predict is how the global mean surface air temperature varies naturally, and responds to changes in atmospheric composition and solar insolation. We usually focus on temperature anomalies, rather than the absolute temperature that the models produce, and for many purposes this is sufficient.
Figure 1 instead shows the absolute temperature evolution from 1850 till present in realizations of the coupled climate models obtained from the CMIP3 and CMIP5 multimodel datasets. There is considerable coherence between the model realizations and the observations; models are generally able to reproduce the observed 20th century warming of about 0.7 K, and details such as the years of cooling following the volcanic eruptions.
Yet, the span between the coldest and the warmest model is almost 3 K, distributed equally far above and below the best observational estimates, while the majority of models are cold-biased. Although the inter-model span is only one percent relative to absolute zero, that argument fails to be reassuring. Relative to the 20th century warming the span is a factor four larger, while it is about the same as our best estimate of the climate response to a doubling of CO2, and about half the difference between the last glacial maximum and present.
http://curryja.files.wordpress.com/2013/10/figure.jpg
To parameterized processes that are non-linearly dependent on the absolute temperature it is a prerequisite that they be exposed to realistic temperatures for them to act as intended. Prime examples are processes involving phase transitions of water: Evaporation and precipitation depend non-linearly on temperature through the Clausius-Clapeyron relation, while snow, sea-ice, tundra and glacier melt are critical to freezing temperatures in certain regions. The models in CMIP3 were frequently criticized for not being able to capture the timing of the observed rapid Arctic sea-ice decline.
While unlikely the only reason, provided that sea ice melt occurs at a specific absolute temperature, this model ensemble behavior seems not too surprising when the majority of models do start out too cold.
In addition to targeting a TOA radiation balance and a global mean temperature, model tuning might strive to address additional objectives, such as a good representation of the atmospheric circulation, tropical variability or sea-ice seasonality. But in all these cases it is usually to be expected that improved performance arises not because uncertain or non-observable parameters match their intrinsic value – although this would clearly be desirable – rather that compensation among model errors is occurring. This raises the question as to whether tuning a model influences model-behavior, and places the burden on the model developers to articulate their tuning goals, as including quantities in model evaluation that were targeted by tuning is of little value. Evaluating models based on their ability to represent the TOA radiation balance usually reflects how closely the models were tuned to that particular target, rather than the models intrinsic qualities.
These issues motivate our present contribution where we both document and reflect on the model tuning that accompanied the preparation of a new version of our model system for participation in CMIP5. As decisions were made, often in the interest of expediency, a nagging question remained unanswered: To what extent did our results depend on the decisions we had just made?
Do you know the answer?
It is mainly Bob’s argument that models are tuned to the period of the late 20th century, so it’s up to him to respond to your point specifically.
Steven Mosher, are you purposely trying to misdirect and misinform? My discussion of tuning is about trends. The paper you linked was about tuning to a specific absolute temperature for a specific point in time.
Correction. Because, Steven, you didn’t specify what you were quoting, I assumed you were quoting Brohan et al. 2006, which was referred to at the end your comment. I’ve checked and discovered you were quoting Mauritsen, et al., which I referred to in the post.
The tuning I was referring to for the period of 1976-2005, as discussed in Mauritsen, et al. follows. Let’s start with the closing discussion of Mauritsen et al. (2012). They begin:
“Parameter tuning is the last step in the climate model development cycle, and invariably involves making sequences of choices that influence the behavior of the model.”
Then under their discussion of “2.1. The tuning process”. There they write:
“We tune the radiation balance with the main target to control the pre-industrial global mean temperature by balancing the TOA net longwave flux via the greenhouse effect and the TOA net shortwave flux via the albedo affect. The methodology of tuning the radiation balance may vary between model development groups, and is usually adapted to the specific goals and constraints of the exercise. After a problem has been identified in the coupled climate model, we iterate the following steps until a satisfactory solution is found:
“1. Short runs of single months, or if possible one or more years, with prescribed observed SST’s and sea ice concentration; first with reference parameter settings, and then altered parameter settings.
“2. A longer simulation with altered parameter settings obtained in step 1 and observed SST’s, currently 1976-2005 from the Atmospheric Model Intercomparison Project (AMIP), is compared with the observed climate.”
“3. Implement the changes in the coupled model setup to run under pre-industrial conditions and evaluate the altered climate. Frequently, we make small parameter changes in this step to fine-tune the climate, without first revisiting steps 1 and 2.”
It’s hard to figure out what Mosher is complaining about now, as he never explains himself properly. I suppose one might argue that models are not consciously or intentionally “tuned”. They are based on various physical calculations and parameterisations. There are no “control nobs” inside models that can be turned one way or another to produce a desired output. What happens is that the parameterisations get shifted this way and that, which alters other processes and feedbacks, until eventually you’ve got something that mirrors the temperature record for a designated period of time. There must be various constraints on what is allowable and what isn’t. But to every sensible person, that’s still tuning. But not overt tuning, as such. But with Mosher being Mosher, this distinction without real distinction is important.
So Mosher why the hell have the models gone so wrong and off Target ? ;>(
I haven’t heard one word about the proper “scientific process”. Models are designed and tuned to a particular set of past data using certain variables (the dependent sample). In this case the main variable is CO2 plus some water vapor feedbacks. To test the validity of the model, it is then applied to a new (independent sample). If the projections don’t fit the actual data, there is something wrong with the basic assumptions. This is clearly the case with climate models, which have thus been invalidated.
dbstealey says:
August 28, 2014 at 11:27 am
“…Global warming since the LIA is composed of natural step changes. Those steps are exactly the same — whether CO2 was low, or high. Therefore, there is no “fingerprint of AGW”. It is clearly shown here in über-Warmist Dr. Phil Jones’ chart:”
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
No, the steps are not exactly the same. There clearly was ~0.4 deg C less cooling from 1950 to 1975 than from 1885 to 1910. Also, the warming cycles from 1910-1940 and 1975-2009 are respectively 10 years and 14 years longer than the 20 year warming cycle from 1860-1880.
These trend differences could possibly be considered fingerprints of Anthropogenic Global Warming (AGW) if we didn’t know that there was comparable warming to modern warming in the Roman Warm Period and the Medieval Warm Period. The warming trends back then were almost certainly not fingerprints of AGW.
There is an interesting piece by Andy Revkin at the NY Times (really!) on the connections between the oceans and atmospheric temperatures. For me, the take-home quote from a climate scientist was
“The underlying anthropogenic warming trend, even with the zero rate of warming during the current hiatus, is 0.08 C per decade.* [That’s 0.08 degrees Celsius, or 0.144 degrees Fahrenheit.] However, the flip side of this is that the anthropogenically forced trend is also 0.08 C per decade during the last two decades of the twentieth century when we backed out the positive contribution from the cycle….”
http://dotearth.blogs.nytimes.com/2014/08/26/a-closer-look-at-turbulent-oceans-and-greenhouse-heating/?_php=true&_type=blogs&smid=tw-share&_r=0
Warming of 0.8 C per century is not frightening.
CAGW is in a dying screaming death spiral.
The comment by Carl Wunsch is gets to the heart of the matter.
For example, 0.08C +/- 0.1C, is consistent with the null hhypothesis of zero..
Wouldn’t 1945 be a better starting point consider it is when man-made CO2 really started up up and away and became the blade of a hockey stick.
http://sunshinehours.files.wordpress.com/2014/04/cdiac-co2.jpg
Yes. But the warming since c. 1945 is no different from the warming in the early 20th century, & much less impressive than that in the early 18th century, among prior natural warming intervals.
I always figure it should be 1935. By 1938 industrial factories in Europe, russia, and Japan were in high gear, burning coal and oil as fast as they could dif it out of the ground. The US joined in that industrial fray in 1940. By 1943 US industrial output and thus energy use was up almost 300%over 1939. There was a big bad recession in 1946-1947 as factories retooled.
You are assuming that four valleys of extreme industrial concentration (Germany’s Ruhr Valley, Pittsburgh’s PA, UK’s London (Thames and surrounds) and California’s LA basin) are typical of the rest of the world. Those four WERE extremely polluted, but are a very, very small part of the whole world. And, even around Pittsburgh, once you were a few miles from the steel mills and glass factories, the air cleaned up remarkably.
Further, three of the four cleaned up between 1945 and 1950. (LA got worse until the early 70’s). Pittsburgh was sandblasting downtown to clean buildings as early as 1947.
Note that we are globally cooling/
http://blogs.24.com/henryp/files/2013/02/henryspooltableNEWc.pdf
that might become a challenge?
Maybe more than you presently know
http://wattsupwiththat.com/2014/05/29/glacial-inception/
If 1945 was the inflection point, it warmed faster before 1945 than it did after 1945.
http://www.woodfortrees.org/plot/hadcrut4gl/from:1900/to:1945/plot/hadcrut4gl/from:1900/to:1945/trend/plot/hadcrut4gl/from:1945/to:2014/plot/hadcrut4gl/from:1945/to:2014/trend
http://sunshinehours.files.wordpress.com/2014/04/candle_1945_2014.png
Dr. Curry made the point, and it’s been mentioned many times, if CO2’s affect is only noticeable post 1950, then where id the 1910-1940 rise come from? None of these so called Climate scientists have explained how one is natural and one is man made. Only that in the second that is greater than the first can logically be attributed to man.
You must be able to show me a certificate of re-calibrated thermometer before 1945 then.
@Bob Tisdale’s
“The climate models are not only out of phase with the long-term data, they are out of touch with reality.”
+10!
“It is difficult to get a man to understand something when his job depends on not understanding it.”
— Upton Sinclair
G.E. Pease,
The steps are exactly the same, when considering even microscopic error bars. Furthermore, there is no empirical evidence showing any ‘fingerprint of AGW’. None at all. There are no measurements of a fraction of a degree warming that could be directly attributable to human emissions. Thus, the default conclusion must be that all global warming is natural, unless shown to be otherwise. To show that would require verifiable measurements. But there are no such measurements.
It is like someone doing an overlay of CO2 and temperature, and saying, “Look! Rising CO2 causes rising temperature!” They do that all the time. But a temporary, coincidental correlation proves nothing. And that T/CO2 relationship broke down, both before and after a short periord from about 1980 to 1997.
Global temperature has been rising at the same rate, as NikFrom NYC shows above, for hundreds of years. There is no evidence at all that human CO2 emissions cause any warming. Any such AGW is mere speculation, and it would anyway be so minor that it can be completely disregarded.
The onus is on the alarmist crowd to support their CAGW conjecture. They have failed miserably, so now their tactic is to make baseless assertions as if they were fact. They aren’t. And without real world measurements, their conjecture fails.
I both agree and disagree with both Bob and Judith/Gavin, but on several different issues:
First: Why is the year 1950 chosen as when AGW supposedly started? That just makes no sense. Please look at the data: Take HadCRUT4 for example. It clearly shows several periods of increasing and decreasing temperatures, each of about 30-34yrs long, making for a 60+ year cycle.
This can be easily and nicely shown with a MACD, which I’ve shown last year here:
http://wattsupwiththat.com/2013/10/01/if-climate-data-were-a-stock-now-would-be-the-time-to-sell/
Clearly the year 1950 is at the start of a 30+ year cooling trend that started in 1945 and ended in 1976. In other words: temperatures peaked in 1945 and bottomed in 1976. How then can there have been (AG) warming since 1950? That makes no sense. Cycle analyses will, thus, tell you when and where temperature trends change. One has to start “counting” from those trend changes. Otherwise you are mixing cyclical warming and cooling periods.
Second: This also means that 1976 is a more appropriate year to look for any AGW signal. However, as I’ve shown in my MACD article, the increase in GSTA during the latest warming cycle, 1976-2007, is 0.019°C/yr, whereas that of the previous 30 yr warming period: 1911-1945 was 0.014°C/yr. Hence, assuming all else equal (i.e. nature… very dangerous to do that in science btw), then the last period had a warming rate that was 0.005°C/yr (36%) higher than the that of the previous warming period. So the maximum possible human influence is 36% IMHO. Note that a) the MACD analyses finds the same years and warming rates as Bob presented and b) that since 2007 the temporal trend in GSTA is effectively 0.
1950 makes “sense” because it makes the average rate of warming in the time frame smaller, so a larger part of the rate of warming can be attributed to AGW.
aka cherry picking.
Cherry-picking one way or the other. It may have been chosen for whatever reason originally and then found to be “convenient”. Speaking of fruit, it’s also apples and oranges. The time frame is from 1950 to “the present”, which is different for each successive IPCC report.
Exactly correct.
Current data is not supporting AGW theory. In addition past climate changes before this idea of AGW came about were many times greater in magnitude then the slight warming which occurred last century. Again the data in this case past data does not support AGW.
Yet they insist.
For my money I attribute all climate changes due to natural causes and 0% to human activity.
I noticed the difference in the starting from the proclaimed “CO2” age of 1950 and most of the graphs only going back to the late 70s. But never thought about it skewing their models as well. Kudos for pointing out the merely obvious to me!
If, as we have been told, that there has been no warming for over 17 years, how can there be an argument on how much warming from 1950 to now can be attributed to man?
No warming from 1950 to 1976, warming from 1977 to 1996, then no warming again from 1997 to 2014 & counting. That’s 20 years of warming (with some down years) vs. 44 (inclusive) years of no warming (or cooling), all the while CO2 has been rising monotonously. CACA was born falsified.
Paper from Green Continent of Oz, comparing CO2 with T, as observed, measured & adjusted:
http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0CEIQFjAC&url=http%3A%2F%2Fwww.lavoisier.com.au%2Farticles%2Fgreenhouse-science%2Fclimate-change%2Fquirk-2011-almanac-of-the-atmosphere.pdf&ei=uaL_U7qmIdW6ogTxgoGABQ&usg=AFQjCNGBVpE_FE9qxOyozevDMzqRZA2-wA&sig2=xUsDH5UKtLeft_tcwFCCZQ&bvm=bv.74115972,d.cGU
The probability density function for the fraction of warming attributable to human activity….
What is this? Counting the male-female ratio of angles on the head of a pin?
“Twice nothing is still nothing.” – Cyrano Jones
Forget the ratio. It is an intractable measure of a religious concept — impossible to test.
What is PDF for the absolute warming attributable to the growth in anthropomorphic green house gasses.
What is the PDF for natural warming elements? for the past 6 decades, For the past 2 millennia.?
Well said.
In mathematics and logic it is easy to define entities that don’t exist (e.g. “Let X be the set of entities that don’t exist”). That is why mathematics usually require existence theorems to prove that any such entities actually exist before trying to characterize and deduce truth from them.
Where is the proof of existence for this pdf (without begging the question)?
Antarctic Urban Heat Effect.
http://www.martingrund.de/pinguine/station.htm#1
Honestly, I am astounded at the utter ignorance of the people involved in climate “science”. I have seen no decent theory backed up by experiment and evidence that CO2 has any net effect on the climate of the planet. In fact, I have seen published charts and graphs that suggest that CO2 has no or nearly no effect at all. And yet we have supposedly educated men and women claiming anthropogenic warming to a precise measure as if they knew Mother Nature’s contribution to the whole affair. Unbelievable ignorance, delusion, and arrogance.
Of course since the government funded temperature data sets are now so corrupted as to be useless: how can we look for real causes of climate change? I notice that even this site calls the best European blog of last year a dispenser of “way out there theories”. Looks to me like the theories we have now are bunk and we need to be working on something else.
To paragraph 1, do not be astounded. Their academic or government careers, grant funding, and personal status all depend on it. To phrase it differently, climate science increasingly resembles the worlds oldest profession.
To paragraph 2 part one, that is going to be an Achilles heel.
To paragraph 2 part two, truth is not always found in popularity contests despite the supposed ‘wisdom of crowds’. Were it so, then tulip bulbs would be more valuable than gold and present shareholders in the South Seas Company would be richer than Bill Gates. (h/t IIRC Mackey”s famous old book on the madness of crowds.)
Why would anyone take any notice of Judith Curry? She is not a dispassionate seeker after truth. In this interview she refers to the “Kock-funded climate denial machine”: http://oilprice.com/Interviews/The-Kardashians-and-Climate-Change-Interview-with-Judith-Curry.html
It looks like she is merely pointing out the strategy of blaming the Kochs, and that it isn’t working.
She’s describing ‘the climate science communication paradigm’ and why it fails, not her position in the debate.
This strategy hasn’t worked for a lot of reasons. The chief one that concerns me as a scientist is that strident advocacy and alarmism is causing the public to lose trust in scientists.
It’s quite clear when you read the full interview.
David
She is making reference to the paradigm not her position
tonyb
You think he doesn’t know that? He is bomb throwing he simply doesn’t care.
That pdf is the single worst thing i have seen in climate science. There is just no way you can create such an attribution given the unknowns.
At least the hockey stick had some basis to it…
The most damning aspect of Gavin’s argument that the cherry-picked 1976~2005 warming period is almost entirely attributable to CO2 forcing, is that its warming trend is similar to the warming period to the 1921~1943 warming period (0.14/decade, 0.19c/decade respectively), and the 1921~43 warming trend can’t possibly be attributable to CO2 because even the IPCC admits CO2 levels were too low in the first half of the 20th century to have caused much warming.
What these two warming periods do have in common is that the PDO was in its 30-yr warming cycle during both of these warming periods.
http://www.woodfortrees.org/plot/hadcrut4gl/from:1850/to:1880/plot/hadcrut4gl/from:1850/to:1880/trend/plot/hadcrut4gl/from:1880/to:1921/plot/hadcrut4gl/from:1880/to:1921/trend/plot/hadcrut4gl/from:1921/to:1943/plot/hadcrut4gl/from:1921/to:1943/trend/plot/hadcrut4gl/from:1943/to:1977/plot/hadcrut4gl/from:1943/to:1977/trend/plot/hadcrut4gl/from:1977/to:2005/plot/hadcrut4gl/from:1977/to:2005/trend/plot/hadcrut4gl/from:2005/plot/hadcrut4gl/from:2005/trend
The PDO entered its 30-yr cool cycle in 2005, and that’s precisely when global temp trends started falling again, despite record amounts of CO2 emissions.
Earth’s warming and cooling cycles have followed PDO warming/cooling cycles almost perfectly for the past 164 years. Accordingly, It’s illogical to assume CO2 is the primary driving force behind global warming since 1950, because from 1950~1976 global temps were falling (PDO cool cycle in effect) and when a global warming trend started again in 1976, it coincides when the PDO entered its 30-yr warm cycle.
The empirical evidence suggests that for the next 20 years, global temp trends should continue to fall, which will be the death knell for CAGW.
It will happen w/i the first 5 years as temps fall. AGW as a science hypothesis just becomes untenable in the scenario.
Is it just too obvious that the oceans act as an enormous heat sink that moderates atmospheric temperature?When the heat content of the entire atmosphere is the same as the top 10 meters of the ocean, and when there are 321 million cubic miles of ocean, most of which is at or below 4C, how is it surprising that there is incredible buffering capacity for temperature changes?
Bingo!! Ding ding ding ding!! Flashing lights. Winner!!!
The oceans control the thermostat, as they have for a billion years once our sun matured. The stupid thought that man’s fossil fuel CO2 is the thermostat regulator is total BS.
Thanks, Bob. Very good information about GCMs training; the models are specialists.
Why would the climate modelers base their projections of global warming on the trends of a cherry-picked period with a high warming rate?
To better scare the money out of our pockets, of course.
But, it seems to have come back to haunt them.