Sheldon wanted to know:
How much of the 2015 temperature increase do you think is due to el Niño, and how much do you think is due to AGW?He got a lot of help, including from OSweetMrMath but didn't know what to do with it. I sent him over to The Carbon Brief at one point, to where a number of different scientists explained how they estimated the contribution of El Niño to last year's record heat. So over he trotted. Rather than come back to HotWhopper, his next port of call was WUWT where he repeated the errors he made here at HW. Anthony Watts posted the following extremely dumb, extremely wrong claim as his headline to Sheldon's error-ridden article:
Hottest year ever update: El Niño effect in 2015 was 20 times larger than the global warming signal
For example, despite being corrected, Sheldon wrote:
The temperature change between the end of 2014, and the end of 2015, is 0.371 °C. (see calculation 1 – all calculations are documented at the end of this article)
We know from the linear regression that the temperature change due to Global Warming for 1 year is 0.0175 °C.
Therefore we can calculate that the warming due to El Nino is 0.3535 °C. (see calculation 2)
Do you see what Sheldon did?
- He subtracted the monthly temperature anomaly for December 2014 (0.634 C) from that of December 2015 (1.005 C) = 0.371 C
- He estimated the linear trend from 1975 to 2015 inclusive at 0.0175 (and wrongly assumed that this would have been the temperature rise from December 2014 to December 2015, if not for El Niño)
- He deducted the linear trend from the difference between the two Decembers and
- Claimed that this meant that the warming due to El Niño was 0.371 minus 0.0175 = 0.3535 C
In other words, he not only mixed up monthly data and annual data, he seems to have decided that without El Niño, the annual global mean surface temperature anomaly would be 0.745C minus 0.3535 C = 0.3915 C. Here is what that would look like:
Using Sheldon's numbers, without the current El Niño, the global mean surface temperature would be back to what it was twenty years ago!
Update: In the comments Sheldon clarifies (I think) that he was only meaning to compare the two Decembers. He didn't mean to argue that El Nino contributed most of the warming for the entire year of 2015, only for the month of December 2015. Or I think that's what he's saying. There are still some inconsistencies in his article, if that's the case.
Sou 9:00 pm AEDT 5 February 2016
Except that might not be what he intended at all. He seems to have got himself all confused, despite all the assistance we gave him. He's certainly got me confused (about what he's arguing). He wrote:
This means that the temperature change due to El Nino was over 20 times bigger than the temperature change due to Global Warming. (see calculation 3)
In other words, El Nino was responsible for over 95% of the temperature change between the end of 2014, and the end of 2015.
Global Warming was responsible for less than 5% of the temperature change between the end of 2014, and the end of 2015.But that's not what he calculated. Using Sheldon's estimate, El Niño was responsible for 0.3535 C of warming, which is:
- Twice the size of the difference in temperature between 2014 (0.57C) and 2015 (0.75C)
- More than twenty times his linear trend from 1975 to 2015 (0.0175 C a year)
- Twenty one times greater than the linear trend from the most recent change point (1970).
As I said, he came to HotWhopper to seek advice for, as it turns out, his WUWT article. He took part of the advice in that he went to The Carbon Brief as suggested. Thing is, he didn't understand what was written there any more than he understood the comments here at HW. He wrote:
As you read the following quotes, remember that this analysis showed that El Nino was responsible for around 95% of the temperature change between the end of 2014, and the end of 2015. El Nino caused an increase in temperature of about 0.32 °C, but the climate scientists claim that it was only a few hundredths of a degree.Instead of questioning his own wrong calculations, given what the experts worked out, and being a typical science denier, Sheldon decided that all the experts were wrong and he was right. He wrote the estimates from the experts and seemed to be surprised that they were unsurprisingly close. Sheldon exclaimed:
All of those scientists certainly seem to be singing from the same songbook!
Then, apparently unaware that the scientists did justify their comments in the article at The Carbon Brief, Sheldon added:
I would like to see these scientists justify their comments, using numerical calculations to show where they got their figures from. I have fully documented my method here. If anybody can point out an error in my results, then please let me know.So I'm letting Sheldon know once more the error in his results. But first, how did the experts arrive at their estimates:
- Gavin Schmidt estimated that El Niño contributed about 0.07 C to the 2015 average temperature. As mentioned in the article: "Schmidt’s analysis uses one indicator of El Niño conditions, known as the “Oceanic Niño index” (ONI)."
- Thomas Cropper estimated that El Niño contributed about 0.09 C to the 2015 average. As mentioned in the article, his estimate was based on the Multivariate ENSO index (MEI), which was used by Foster and Rahmstorf (2011).
The MEI was explained at The Carbon Brief in letters too large for Sheldon to see:
The MEI is based on six variables which can quantify El Niño and La Niña events – sea level pressure, surface winds in both north-south and east-west directions, sea surface temperature, surface air temperature, and the fraction of the sky covered by cloud.So where did Sheldon go wrong exactly?
First of all, Sheldon went wrong by subtracting the month of December 2014 from the month of December 2015 and claiming that represented the amount that El Niño contributed to the annual global mean surface temperature for 2015. That gave him an inordinately large difference of 0.3535 C, much greater than the year to year difference of 0.178 C. Thing is, El Niño was only declared in May last year, and it only got big enough to exert a notable influence later in the year. That's roughly illustrated in the chart below, which is a plot of 2015 minus 2014 temperature anomalies for each month:
As pointed out in Roz Pidcocks's article, "it’s important to look at any individual year in the context of the longer trend". Month to month and year to year data is noisy. It's the long term trend that's important.
Sheldon also went wrong in his surprise that the scientists' estimates were not too different.
And he went wrong by ignoring the explanation of how the scientists reached their estimates of El Niño's contribution, and asking how they justified their estimates.
I have to say that I didn't much like his table, either. Not just because it was woefully wrong, but because the writing was too small to read easily. (It was woefully wrong because it was based on the difference between December monthly temperature anomalies.)
Sheldon made another error in taking no notice of any of the responses to his question and comments here at HW.
Finally, he went wrong because from here he trotted over to WUWT to repeat his mistakes.
Incidentally, it's expected that El Niño will have a bigger influence on this year's average surface temperature. That's generally the pattern of a strong El Nino.
Since the article at HotWhopper and the article at the Climate Brief, Tamino has written an article as well. Sheldon must have missed it.
From the WUWT comments
Pointman builds a strawman. Not every year is the hottest on record. Last year was, and the year before that was, and so were 2010 and 2005 and 1998 at the time. There hasn't been a "coldest year on record" for more than 100 years.
February 4, 2016 at 7:34 am (excerpt)
Every year is the hottest one, every year and every year ad nauseum. No wonder people no longer believe the alarmists.
I thought Werner Brozek was smarter than this. I was wrong, and probably shouldn't have been surprised.
February 4, 2016 at 7:34 am
Thank you for a well presented argument!
By the way, there was a typo in the table. It should be Hadcrut4 and not Hadcrut3
Newminster is a climate conspiracy theorist who is waiting patiently for "one day":
February 4, 2016 at 7:47 am
Personally I find nothing at all surprising in climate scientists talking up the global warming aspect and underplaying the El Niño contribution.
It’s what they do, but it will catch up with them one day.
hswiseman suffers from confirmation bias, has a vivid imagination, and seems to think that the oceans decided to warm up the world by magic:
February 4, 2016 at 7:57 am
It was hysterical watching the warmists cheer on the El Niño like it was some kind of a football game. They were too ignorant to realize that the huge temperature forcing impact of El Niño and oceanic circulation in general implicitly revealed the minimal forcing effect of additional carbon dioxide upon atmospheric temperature. The oceans are the big dog in the temperature story. Carbon dioxide is just a bunch of fleas on the dog.
D. J. Hawkins wonders if scientists, who first told him about such things as La Ninas and El Ninos, will tell him again how La Nina cools the surface. Or maybe he thinks they will tell him something different from what they've told him up to now:
February 4, 2016 at 10:22 am
What are they going to do when the anomaly comes crashing down at the end of this El Niño?
tadchem tries to give the WUWT-ers some home truths. They take it the wrong way (maybe tadchem is a denier and didn't see the irony)
February 4, 2016 at 8:07 am
When you *really* want to believe something, the facts are nearly irrelevant.
Steven Mosher, in a very long comment for him, pointed out an invalid assumption from Sheldon, and more:
February 4, 2016 at 8:36 am (excerpts)
“We know from the linear regression that the temperature change due to Global Warming for 1 year is 0.0175 °C.”
Ah no you don’t know that. ...
...For grins.. take your time series and make a time series going back to 1880 using only el nino yearsHere it is, going back to 1900 (as far as I could go). I added a 3rd order polynomial trend line, which seemed about the best fit, but don't take that as gospel:
Do the same for La Nina
kokoda is so far into denial that he or she cannot accept any evidence of global warming, no matter how strong, and prefers to believe that climate science is a hoax:
February 4, 2016 at 9:01 am
We can stop pretending that Global Warming (AGW) has a statistically scientific impact on global climate when there is no evidence for the claim (besides deception, conjecture, and hyperbole).
kokoda later admits that for him or her, numerical analysis is not important.
February 4, 2016 at 8:49 am
Numerical analysis is not important. “We think” is the science of the day.
Scottish Sceptic is another WUWT climate conspiracy fruitcake of the type treasured by Anthony Watts:
February 4, 2016 at 8:54 am
Why use discredited surface data which everyone knows is fraudulent?
References and further reading
Analysis: How much did El Niño boost global temperature in 2015? - article by Roz Pidcock at The Carbon Brief, 26 January 2016
el Niño and the 2015 Record-Breaking Heat - article by Tamino, 27 January 2016
From the HotWhopper archives
- Desperate Deniers Part 6: David Whitehouse sez it's just a blob and ENSO - in which Sheldon Walker sought information for his WUWT article, 24 January 2016
- It was cold in the 1930s, really it was (compared to now) - about how Sheldon Walker distorted data to argue at WUWT that it's not that bad, August 2015