Guest Post by Willis Eschenbach
Richard Muller and the good folks over at the Berkeley Earth Surface Temperature (BEST) project have released their temperature analysis back to 1750, and are making their usual unsupportable claims. I don’t mean his risible statements that the temperature changes are due to CO2 because the curves look alike—that joke has been widely discussed and discounted, even by anthropogenic global warming (AGW) supporters. Heck, even Michael Mann jumped on him for that one, saying
It seems, in the end–quite sadly–that this is all really about Richard Muller’s self-aggrandizement 🙁
And if anyone should know about “self-aggrandizement”, it’s Michael Mann … but I’m not talking about Muller’s claim that humans caused the warming. No, I mean the following statement:
The historic temperature pattern we observe has abrupt dips that match the emissions of known explosive volcanic eruptions; the particulates from such events reflect sunlight and cool the Earth’s surface for a few years.
In support of this statement, Richard Muller offers up the following chart:
Figure 1. BEST claims about temperature and volcanoes. SOURCE
So what’s not to like?
Well, first it appears he has included and excluded volcanoes depending on whether they show up in his temperature record. If we look at big eruptions, eruptions with a “volcanic explosively index” (VEI) of 6 or above, since 1750 we have the following volcanoes:
Mount Pinatubo, 1991
Novarupta, 1912
Santa María, 1902
Krakatoa, 1883
Mount Tambora, 1815
Grímsvötn and Laki, 1783
So Muller has left off Santa Maria and Novarupta, and included El Chichon and Cosiguina. But that’s not the real problem. The real problem is that many of these occurred after or during the temperature drop that they are supposed to have caused … here’s the BEST data including all relevant volcanoes, without the style of overlay that they have used that obscures the actual timing:
Figure 2. BEST temperature data and dates of volcanoes. Red line is a four-year centered Gaussian average of the temperature data. Photo shows Mt. Redoubt in Alaska.
So let’s look at the volcanoes, one by one:
LAKI, 1783: Occurred near the end of the fall in temperature that it is supposed to have caused.
TAMBORA, 1815: Occurred at the end of the fall in temperature that it is supposed to have caused.
COSIGUINA, 1835: Occurred near the middle of the fall in temperature that it is supposed to have caused.
KRAKATOA, 1883: Occurred at the end of the fall in temperature that it is supposed to have caused.
SANTA MARIA, 1902: Occurred in the middle of the fall in temperature that it is supposed to have caused.
NOVARUPTA, 1912: I can see why Muller omitted this eruption, which occurred just before a rise in temperature …
EL CHICHON, 1982: Occurred during the fall in temperature that it is supposed to have caused.
PINATUBO, 1991: This is arguably the only one of the eight volcanoes that could legitimately be claimed to cause a detectable fall in temperature … a whopping fall of 0.15°C or so.
So while volcanoes certainly may cause a minor drop in global temperature, the claim of Richard Muller and the BEST folks that there are “abrupt dips that match the emissions of known explosive volcanic eruptions” is simply not true. There are abrupt dips, but they don’t match up with the volcanic eruptions.
w.
[Update] Further reading:
Prediction is hard, especially of the future discusses the GISS analysis of Pinatubo.
Missing the Missing Summer is about the eruption of Tambora.
Dronning Maud Meets the Little Ice Age investigates a claim that the Little Ice Age was triggered by vulcanism.
Volcanic Disruptions plays the game “Spot the Volcano”
[Update] Another way to investigate the question is to look at the average temperature anomaly during the two years before and the two years after the eruption. Figure 3 shows that result.
Figure 3. Average temperature anomaly two years before and two years after the eruptions. Black lines show the standard error of the mean.
After some eruptions it cooled a bit, after some it warmed a bit, and after some there was no change … go figure.
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Wonderful forensic dissection of the usual warmist cack.
Why do these people keep lying and keep thinking they can get away with it?
So what we really might have is a possible relation with falling temps causing large volcanic eruptions…. /sarc
If you think up a theory get the facts to correlate otherwise theory goes down.
I continually seem to suffer cognitive dissonance with this sort of thing. Willis presents figures with which it is hard to argue *and* they’re easy to find. A group of reputable scientists have access to the same figures and draw an opposite conclusion. One bit of me wants to believe the scientists, but the other just looks at the graph. Is it any wonder I’m sceptical and my head hurts?
Don’t forget that a four year centered Gaussian average would start reacting to an abrupt drop two years ahead of time. Even so this doesn’t rescue the claim.
But CO2 always rises after the temperature rises it causes (but only 400 years after), so it stands to reason that volcanic eruptions do the same: they happen after the temperature drops they cause. (Well, some of the time anyway.)
“Climate Science” is incredibly difficult. No wonder it’s only the geniuses of ‘the team’ and their acolytes who can understand it. We denialist scum don’t have a snowball’s chance. Even Einstein would have struggled to understand the temporal complexities involved…
(/sarc. Just in case…)
Ian H, that’s a good point. If we are going to look at the effects of point events then any form of spreading on the data needs to be avoided. Also is there anything odd about Novarupta that might explain why it seems to have a positive effect (though it could all be coincidence).
Ian H says: July 30, 2012 at 3:29 am
“Don’t forget that a four year centered Gaussian average would start reacting to an abrupt drop two years ahead of time. Even so this doesn’t rescue the claim.”
I would have thought more like four years (if sd=4), which does make the claim look better. Only Novaruptna looks to me to be totally out – some of the others seem to be a rather weak response.
It’s very interesting that in this paper they pointed out the effect of Pinatubo (1991, typo in post).
Previously, they forgot about Pinatubo when it suited their argument: Look at the FAQ on the BEST page, under “Has Global Warming Stopped?” and you’ll read “However, if you did that same exercise back in 1995, and drew a horizontal line through the data for 1980 to 1995, you might have falsely concluded that global warming had stopped back then.” No mention of Pinatubo. This was misleading of course because that pause was related to the eruptions, whereas the present one isn’t.
I’ve been trying to find Galeras (1993) in the lists, but nobody takes it into account, in spite of the victims. It occurred in january, (summer season in the souther hemisphere ), two years after Pinatubo. But in the chart, the temperature goes up. No visible dent.
Why is it so ?
Now this should be a simply one , the date a Volcano goes bang big style is easy to know , the temperatures over a period are easy to know , as the date is there taken on are recorded . So it is straight forward to see if there a link between them .
What we see here is a classic way in which statistics can be used to what is know to appear to be wrong because manipulating the numbers produces ‘accurate ‘ but wrong data . In other words its statistically created lie.
Ian H says:
July 30, 2012 at 3:29 am
Don’t forget that a four year centered Gaussian average would start reacting to an abrupt drop two years ahead of time. Even so this doesn’t rescue the claim.
Indeed. The smallest wiggles just before (two years is not much in this image!) and after Laki and Tambora may still be consistent with a cooling by the volcanoes, but not the drop in temperature several years in advance.
George says:
July 30, 2012 at 3:12 am
So what we really might have is a possible relation with falling temps causing large volcanic eruptions…. /sarc
I see that /sarc-tag, but I wouldn’t completely rule out a common cause…
Don’t forget there is statistical uncertainty over laid on the volcanic timings hence, the timings can be pushed forward or back depending on what cooling/warming trend was at the time.
Also, there’s an elementary error in their graph. El Chichon was 1982. The arrow on their graph points to early 1960s which was Agung.
I was looking at the Tambora eruption and not comparing it with the Berkley data – just trying to square it with the “Year Without a Summer” (1816) observations in the northern hemisphere. Does the data show some dramatic warming elsewhere on the globe or was the winter (1815 or 1816) not as cold as normal despite the summer conditions? I merely point it out because the “Year without a Summer” is after the Tambora event.
What happens to the actual temperature record after each eruption, forget about gaussian smoothing as we’re looking for patterns of cause and effect?
Muller threw Mann under the bus years ago, in an attempt to become the Golden Child of AGW, and now Mann is showing his professionalism in return.
Nick,
Rather than ‘weak response’ IMO what you really mean is that for most of these volcanic eruptions there is more or less a non-existant response to the eruption when you fully allow for the year to year variability in the anomaly index.
IMO the correlation between ‘volcanic eruptions and cooling of the planet’ argument is very weak and is used as a ‘sticking plaster’ by warmists like your good self (i.e. that man-made or non man-made ‘dust’ causes cooling) to try and explain away the 1940 to 1970 global cooling period. The reality is that this well established cooling period has nothing to do with ‘particulate emissons’ from the post WW2 global industrial expansion and everyting to do with the approx. 60 year (most likely wholly) natural cyclic climatic variations we experience in the earth’s climate, the cause of which we are only just beginning to identify and understand.
KevinUK
As the song says: “Two outa three ain’t bad”, but one outa seven?
That reminds me of http://xkcd.com/925/
And the 1980 Mount St Helen eruption, in mid may, after a couple months of earthquakes , and a really big one just the day before. That was a major eruption , but it is not shown on the graph, either.
Novarupta’s high latitude position meant its eruption had relatively little effect on global climate. Try Kravitz and Robock 2011.
Looking at the BEST curve in the media, it seems as if the only function of the pre-1900 volcano data is to make the curve match look good. The 20th century match to CO2 is just a general rise, in fact my age correlates better with the CO2 than the temp does.
Maybe the cooling CAUSES the volcanos – i.e. making the earth’s mantle more brittle or something?
/sarc off
can someone enlighten me as to what the units are for the solid (dark) line on the Berkley plot?