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
Leif Svalgaard says:
August 15, 2010 at 3:58 pm
Steve Goddard says:
August 15, 2010 at 3:05 pm
“The study went through 1996, not 1998”
but the verification of their prediction was for 2010: “predicted in 1999, using temperature data from 1946 to 1996, that by 2010 global temperatures would rise by 0.8C, no?
Which it did precisely, so good prediction. Kudos to them. It is rare that climate predictions come out so well, wouldn’t you agree?
Leif,
Do you just like to argue? Second World War was 1939-1945. Average HadCrut anomaly during that period was -0.010125. Last full year anomaly (2009) was 0.438.
0.438 – -0.010125 = 4.27
Rounded to 4.0C, just as I said.
Ian H says:
August 15, 2010 at 12:43 pm
Something happening in New Zealand you all might want to look at
…………………………………………………………………………………………………………………..
From the article you linked:
Court action against New Zealand’s state-owned weather and atmospheric research body is “stupid” and just creating confusion, University of Otago pro-vice chancellor of sciences Keith Hunter says.
Everyone has their opinion. Someone also has said Arctic Ice isn’t worth blogging about. But not everyone thinks lawsuits over a temperature set are stupid and that Arctic Ice is not worth blogging about. 🙂
Sorry, cut and paste problem in the calculator – should read
0.438 – -0.010125 = 0.448125
stevengoddard says:
August 15, 2010 at 4:30 pm
Do you just like to argue? Second World War was 1939-1945. Average HadCrut anomaly during that period was -0.010125. Last full year anomaly (2009) was 0.438.
I just comment on what they correctly predicted. They clear started with 1946 for which the anomaly was -0.204, 2010 will be the hottest since back then for estimated +0.6, so increase of 0.8 as they said. If you have a quibble with them, they should probably not have used the phrase ‘second world war level’ when they meant 1946.
Rounded to 4.0C, just as I said.
I have a strong suspicion you meant 0.4C, but let that slide for now.
How does one get the 2010 mean temp before at least the end of 2010?
So when we say the temperature of 1946, do you mean the average temperature of 365.25 24 hour days from stations around the world, land and sea, or noon temperatures over Winnemuca, Nevada, or midnight temperatures over Fargo? What?
Is there a basis to believe the methods of establishing that average temperature are both accurate and similar to how it was done in 1996?
Leif Svalgaard says:
August 15, 2010 at 1:53 pm
Rumor has it that 2010 will be hotter than 1998,
Their magic wand for changing temperature has turned into a bludgeoned. It looks to be the coldest summer on record north of 80N but GISS has it above normal. On the one hand we have DMi that does everything they can to collect data to use for determining temperature and on the other hand we have GISS that does everything it can to use as little data as it can—and is run by a man who has a reputation for radical environmentalism. Who to believe, who to believe…..
soccer, soccer, soccer,…….come one, real football starts on September 9. Are you ready for some football? 😉
I had originally typed this up, but deleted it because I thought it was too pedantic. Guess I was mistaken.
Temperature Anomaly during WWII: Approx +0.02 deg C
Temperature anomaly for last 12 available months of HADCRUT3: Approx +0.51 deg C
So, it looks to be about 0.5 deg C … still a lot closer to 0.4 than 0.8.
The entire HadCrut record from 1850 to the present shows a little less than 0.8C warming.
Leif Svalgaard, we all know now that this global temperature is boggus. So this is truly a discussion about nothing.
“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.”
Interesting, very interesting.
Steve, an in depth article looking at all the various GSMs and their models and how they compare with and differ from weather models would be of great interest.
These silly arguments related to increasing temps, decreasing temps, and since this year or that year is irrelevant in such a complicated system as Earth’s climate. Even IPCC understands that there will be short term trends. There are better ways to talk about this issue than with a linear statistic, and Leif, you know this better than anyone given that you prefer to talk about solar metrics with non-linear statistics.
Leif – you should stick to what you know.
Son’t start medling in the climate.
Physics is mathematical, but mathematics is not physics. Practitioners of these two disciplines chide each other in appropriately abstruse terms; for example, mathematicians cite “The Physicist’s Proof That All Odd Numbers are Prime”:
Three (3) is prime, five (5) is prime, seven (7) is prime. Nine?– well, that’s just an exception– eleven (11), thirteen (13) … AGW Catastrophists, unite– you have nothing to lose but your brains.
If I have a weather model that can tell you with in 1F what temperature it is going to be today, haven’t I explained the reasons the temperature was 90F? Why do climate modelers need the additional factors? Is it because their methodology removes information from the dataset?
stevengoddard says:
August 15, 2010 at 4:40 pm
Sorry, cut and paste problem in the calculator – should read
0.438 – -0.010125 = 0.448125
Steven-
I presume that you were exaggerating for an illustrative purpose, but you know that that many digits after the decimal point can’t be justified.
Aren’t temperature data only to the nearest whole number? My limited knowledge of math and stats says that it’s impossible to have greater precision than the least precise number in the data set.
IanM
The Guardian article refers to “Stott and Myles Allen of Oxford University, predicted in 1999”
Anyone located the source?
Here’s Allen’s site
http://climateprediction.net/content/scientific-papers
neither of the first two references, which are Letters to Nature, seem to reference a prediction for 2010. The second was received in 1999 and published in 2000.
It is interesting though, with reference to 1946 -1996 stats. Look at figure 3.
http://climateprediction.net/science/pubs/nature_allen_051000.pdf
TomRude says:
August 15, 2010 at 5:18 pm
Leif Svalgaard, we all know now that this global temperature is boggus. So this is truly a discussion about nothing.
I didn’t start it.
Pamela Gray says:
August 15, 2010 at 5:50 pm
These silly arguments
somebody made a big deal out of that and occasioned an article on WUWT.
O/T – meanwhile from the same organ … Sunday 15 August 2010 20.59 UTC
Coal-fired power stations win reprieve
There’ll be a lot of new climbing rope sold this week.
Ian L. McQueen
What is obvious is that WWII (1939 – 1945) was about zero anomaly and current is about 0.4.
http://www.cru.uea.ac.uk/cru/info/warming/
How do these useless discussions get started?
Leif,
Why are you wasting my time?
stevengoddard says:
August 15, 2010 at 8:15 pm
How do these useless discussions get started?
A Steven Goddard posts an article…
stevengoddard says:
August 15, 2010 at 8:16 pm
Why are you wasting my time?
You don’t need to respond to every correction…
You don’t need to respond to every correction…
Yes but in the absence of substantive comments as one’s “corrections” approach minutia, then one has likely lost the argument.