By Steve Goddard
Yesterday, the Guardian reported :
Meteorologists have developed remarkably effective techniques for predicting global climate changes caused by greenhouse gases. One paper, by Stott and Myles Allen of Oxford University, predicted in 1999, using temperature data from 1946 to 1996, that by 2010 global temperatures would rise by 0.8C from their second world war level. This is precisely what has happened.
Huh?
The temperature rise since WWII reported by CRU is 0.4C (not 0.8C) and it occurred prior to the date of the study. Climate models use thousands of empirically derived back-fit parameters. Given that fact, the only thing remarkable is that their prediction was so far off the mark. Their forecast is the equivalent of me predicting that Chelsea wins 12-0 yesterday. Off by a factor of two, and after the fact.
I recently attended a meeting of weather modelers, who told me that their models are effective for about 72 hours, not 60 years. GCMs use the same underlying models as weather modelers, plus more parameters which may vary over time.
h/t to reader M White
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Dikran,
Thank you for your conjectures. Apparently you believe — despite satellite evidence — that the global temperature increased from 2000 – 2010.
Instead, you believe the models, which clearly predict a tropospheric hot spot must appear if the CO2=CAGW conjecture is correct. Decisively falsified.
You believe the current climate is unprecedented. Wrong.
You believe the current temperatures are going outside of their historical parameters. Again, wrong.
You believe you understand Karl Popper. Wrong.
You believe the climate models are correct. Wrong. They are 400% off the mark.
You believe the climate is getting worse. Wrong.
You believe the current natural warming cycle is caused by human activity. Wrong.
While you’re getting up to speed on this subject, I will be on the top [BREAKING] thread. You have quite a bit of learning to do here in order to get up to speed. When you think you’ve mastered the difference between a conjecture and a testable hypothesis, and between a scientific skeptic and a pseudo-scientific climate scientist, feel free to join us there.
Smokey writes:
“Thank you for your conjectures. Apparently you believe — despite satellite evidence — that the global temperature increased from 2000 – 2010.”
Give it a break, old chap, [snip], the plot you provide goes from 2002 to 2009, not 2000-2010. I’ll might pay attention to the rest of your posturing if you can give a plot of data for the lat decade (i.e. 10 years working back from the current time) that shows cooling.
BTW, the plot you gave is a good example of the ENSO-based cherry picking I mentioned. It starts in 2002 rather than 2000 replace a weak La Nina with a weak El Nino, and ends in 2009 so as not to include the current El Nino.
stevengoddard says:
August 17, 2010 at 9:36 am
“72 hours is the standard window of accuracy assumed by weather modelers. I’m sorry that you don’t want to believe it.”
ROTFL, nowhere did I say that 72 hours is not the standard prediction horizon for weather modellers. What I did say is that has no bearing on climate prediction for 60 years hence (as implied in the OP). If you are going to argue [snip], then you would be better served with somthing a little less obvious than the above straw man.
CENSORSHIP, CENSORSHIP!!!
Only kidding, sorry mods, message received and understood. ;o)
BTW Smokey, of the list of things you assert I believe, you were right about one of them, wrong on six (I don’t actually believe them) and half right about one (unlike you, I understand Popper enough to be able to point out how Easterling and Wehner could be falsified; however a full understanding of Popper would require rather more study of the phillosophy of science than I have time for, interesting though it is).
Dikran Marsupial
I have been trying to discuss politely with you, and after a dozen posts I really have no idea where you are headed with this rambling discussion.
Steven Goddard writes:
“I have been trying to discuss politely with you, and after a dozen posts I really have no idea where you are headed with this rambling discussion.”
I’m not headed anywhere, I was following your lead. I merely pointed out an error in the OP, which impled that the prediction horizon for weather prediction of only 72 hours had some bearing on climate projection using GCMs – It doesn’t. I have been amused however by your inability to admit that it is of no relevance.
Dikran Marsupial
The “inability” is to make any sense of your arguments.
Climate models use the same underlying code as weather models. If a weather model is used to incorrectly forecast a warm winter (Met Office) then the error feeds back and causes more errors.
22 years ago Hansen made some climate forecasts which bombed. Just as current climate forecasts will do. The same excuses will be made by each successive generation, and they will claim to have it correct “this time.”
If the model is inadequate, billions of dollars in hardware won’t do any better than a $250 netbook.
stevengoddard says:
August 17, 2010 at 12:43 pm
Climate models use the same underlying code as weather models. If a weather model is used to incorrectly forecast a warm winter (Met Office) then the error feeds back and causes more errors.
——-
This is irrelevant as climate models don’t depend on the initial conditions being exactly right, but on the boundary condition. This has been explained several times on this page, and many many times elsewhere, but yet you persist in spreading the canard and wonder why some would call you a denialist.
—–
“22 years ago Hansen made some climate forecasts which bombed.”
Have you tested if the forecast was skillful? Or is that too much like hard work?
richard telford,
You asked : “Have you tested if the forecast was skillful? Or is that too much like hard work?”
WUWT anticipated your question and delivered four days ago. If you want to post here, you really should actually read the articles. Or is that “like too much hard work?”
http://wattsupwiththat.com/2010/08/13/is-jim-hansens-global-temperature-skillful/
G’day, Smokey. May I cut in?
Your example starts in 2002. The temperature trends from 2000 to present for RSS and UAH, plotted with the data they provide are:
RSS = 0.11C/dec
UAH = 0.15C/dec
Here is the plot at wood for trees so you can check for yourself.
(You also get a slight warming trend if you run ‘to 2010’ (ie, 2000 – 2009 inclusive. You don’t get a cooling trend from 2000)
The caveat must be added that you don’t get statistically significant trends with respect to climate at these time scales. These plots are too influenced by weather variation to be meaningful, but the result is still clear even by these poor standards.
stevengoddard says:
August 17, 2010 at 6:28 pm
WUWT anticipated your question and delivered four days ago. If you want to post here, you really should actually read the articles. Or is that “like too much hard work?”
—————————-
I read and commented on that pathetic article some days ago – if you had bothered to check you could have saved yourself another mistake. There are statistical tests of skill. Christy doesn’t bother to use these, preferring to eyeball the data, which gives him his predetermined answer.
Steven Goddard wrote:
“You asked : “Have you tested if the forecast was skillful? Or is that too much like hard work?”
WUWT anticipated your question and delivered four days ago. [blah blah blah]”
I note you failed to answer Richard’s main point, which was an explanation of why the fact that weather forecasting and climate modelling use very similar computational methods does not mean that climate modelling shares the same 72 hour prediction horizon with weather forecasting [because weather forecasting is dependent on knowledge of initial conditions, but climate projections are not]. This is hilarious, given that I had earlier written
“I merely pointed out an error in the OP, which impled that the prediction horizon for weather prediction of only 72 hours had some bearing on climate projection using GCMs – It doesn’t. I HAVE BEEN AMUSED HOWEVER BY YOUR INABILITY TO ADMIT THAT IT IS OF NO RELEVANCE.”
It maybe that GCMs have no forecasting skill, but it is obvious that I do! ;o)
“[actually…. as an anonymous commenter, your irrelevance takes precedence ~mod]”
What a needlessly hostile and unpleasant reply, from an anonymous moderator. I guess it’s easier just to say something rude than it is to address the substance of what I said. Ad hominem, they call it.