Putting the Brakes on Satellite Acceleration

Guest Post by Willis Eschenbach

I discussed acceleration in the tide gauge records in a previous post. However, people are also claiming that either there is acceleration in the satellite record or there will soon be acceleration. So I thought I’d take a look at the satellite-measured sea level question. First, here’s the satellite data:

Figure 1. Satellite-measured global sea level changes, 1993-2016

There are several interesting things about this. First, IF the data is correct the sea level goes up and down a lot. The monthly jump averages about three and a half millimetres, which is larger than the average annual increase.

Next, the rise is far from monotonic, with the Gaussian average (shown in red) actually decreasing about one month in six.

So … is sea level rise accelerating? Visually you’d have to say no, but that’s why we have math. However, in this case, the math agrees with the reading of the Mark 1 Eyeball. If we fit the data with increasing numbers of terms, the only one among them that is statistically significant is the first term (a linear equation). Here are the residuals of fits using from one to five terms:

Figure 2. Residuals from various fits to the sea level data

In addition, in the quadratic fit, the second term (acceleration) is NOT statistically significant (p-value=0.37). So it’s quite clear that there is no acceleration currently visible in the sea level data.

However, apparently this isn’t good enough for the alarmists. Over at the Colorado Sea Level site, I find the following quote from a recent paper entitled “Is the detection of accelerated sea level rise imminent?” by Fasullo et al.:

Global mean sea level rise estimated from satellite altimetry provides a strong constraint on climate variability and change and is expected to accelerate as the rates of both ocean warming and cryospheric mass loss increase over time.

In stark contrast to this expectation however, current altimeter products show the rate of sea level rise to have decreased from the first to second decades of the altimeter era.

Here, a combined analysis of altimeter data and specially designed climate model simulations shows the 1991 eruption of Mt Pinatubo to likely have masked the acceleration that would have otherwise occurred. This masking arose largely from a recovery in ocean heat content through the mid to late 1990 s subsequent to major heat content reductions in the years following the eruption.

A consequence of this finding is that barring another major volcanic eruption, a detectable acceleration is likely to emerge from the noise of internal climate variability in the coming decade. SOURCE

Hey, if the data doesn’t fit the theory, just change the data … what’s not to like?

First thing not to like is that the Pinatubo eruption was in mid-1991 … and the satellite record doesn’t even start until 1993. So they are talking about some kind of really long term reduction. This is much longer than the length of the known effects of the volcano on the atmosphere. These effects show clearly in the clear air solar energy absorption records from Mauna Loa, Hawaii.

Figure 3. Eruption effects on the clear air transmission in Mauna Loa, Hawaii. SOURCE 

There were two large eruptions during that time period, El Chichón in Mexico and Pinatubo in the Philippines. However, the recovery times are short. As you can see, by 1994 the effects of the Pinatubo eruption are gone.

That brings us to the next thing that’s not to like. There is NO SIGN of the claimed “major heat content reduction in the years following the eruption”. Here is the data from the World Ocean Atlas of Levitus et al, showing the changes in heat content for the top 700 metres depth of the ocean.

Figure 4. Global ocean heat content anomaly for the top 0-700 m

Now, as you likely already noticed, there are no years on that graph, and for a reason. They’ve claimed a “major heat reduction” after the 1991 eruption of Pinatubo. And as shown in Figure 3, there’s also the equally large eruption of El Chichón a decade earlier which should have an equally major heat reduction.

So … where in Figure 4 do you think the two eruptions happened?

I ask because unless you know when the eruptions occurred, you can’t see anything anomalous in the record. For me, the best guess for Pinatubo would be the deep notch at the right, or maybe the big drop after the peak two-thirds of the way through the record.

And obviously, the scientists who want to change the data have the same problem—they can’t find the claimed signal in the observational record. Now, any sane scientist would stop there. But these are climate scientists, so instead they take a climate model, show that a modeled “major heat reduction” occurred in the modeled ocean heat content of their modeled earth after a modeled eruption … and then they use that imaginary outcome to bend the data to the desired shape. Acceleration ‘r’ us!

So … where are the eruptions actually located in Figure 4? Figure 5 shows that result.

Figure 5. Global ocean heat content anomaly for the top 0-700 m, with dates of eruptions

You can see why they had to throw out the data and use a climate model … there were two huge volcanoes during that time, but there’s no visible effect on the heat content of the ocean. Heat content went up a bit after El Chichon in 1982 and dropped slightly after Pinatubo. However, check the graph—heat content also dropped about three years before Pinatubo, in an almost identical manner. So there’s nothing significant there.

(I have demonstrated that this lack of response to eruptions is because when the tropics cool down, whether from eruptions or any other reason, the clouds and thunderstorms form later during the day or not at all. This lets in extra sunshine every day which counteracts the heat loss from the eruptions. However, that’s a subject for a different post or two, not this post …)

So I thought, well, maybe I’m looking at too broad a picture when I look at the global ocean. Perhaps there was a reduction that was localized in the area of the eruptions. Given their location we’d expect the largest effects to include changes in the North Pacific. This North Pacific effect is supported by the large eruption-driven reductions in clear-air transmission seen at Mauna Loa (Figure 3). However, the Pacific heat content is shown below.

Figure 6. North Pacific ocean heat content anomaly for the top 0-700 m, with dates of eruptions

Ooops … that shows even LESS of an effect from the eruptions than did the global data—in fact, it goes opposite to the authors’ expectations. In both cases, Pacific oceanic heat content went UP after the eruptions, during the times the authors’ claim there was a “major reduction” in heat content.

Conclusions, in no particular order:

First, it is mathematically clear that there is no sign of any significant acceleration of sea level rise in the satellite data.

Next, the claim that there was a “major heat content reduction” in the oceans after Pinatubo is strongly contradicted by both the global and North Pacific observational data. We see no such thing for either Pinatubo or for El Chichon.

Finally, the models do a lousy job modeling the effects of the volcanoes. I’ve written about this a number of times, see below. The reality is that the effects of the eruptions on surface temperatures are generally small, local, and short-lived.

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It’s a glorious Sunday now that the mist has burnt off. I’ll be in and out next week, my mad mate Gepetto the Puppet-Master has a gold mine in the Southern Sierras that he wants me to invest in. If it were anyone else I’d just laugh … but Gepetto is probably even crazier than I am, so I gotta pay attention to him.

Best to all,

w.

PS—As usual, I politely request that when you comment you QUOTE THE EXACT WORDS YOU ARE DISCUSSING, so we can all understand your subject.

PREVIOUS POSTS ON THE LACK OF EFFECTS FROM ERUPTIONS:

Overshoot and Undershoot 2010-11-29

Today I thought I’d discuss my research into what is put forward as one of the key pieces of evidence that GCMs (global climate models) are able to accurately reproduce the climate. This is the claim that the GCMs are able to reproduce the effects of volcanoes on the climate.…

Prediction is hard, especially of the future. 2010-12-29

[UPDATE]: I have added a discussion of the size of the model error at the end of this post. Over at Judith Curry’s climate blog, the NASA climate scientist Dr. Andrew Lacis has been providing some comments. He was asked: Please provide 5- 10 recent ‘proof points’ which you would…

Volcanic Disruptions 2012-03-16

The claim is often made that volcanoes support the theory that forcing rules temperature. The aerosols from the eruptions are injected into the stratosphere. This reflects additional sunlight, and cuts the amount of sunshine that strikes the surface. As a result of this reduction in forcing, the biggest volcanic eruptions…

Dronning Maud Meets the Little Ice Age 2012-04-13

I have to learn to keep my blood pressure down … this new paper, “Abrupt onset of the Little Ice Age triggered by volcanism and sustained by sea-ice/ocean feedbacks“, hereinafter M2012, has me shaking my head. It has gotten favorable reports in the scientific blogs … I don’t see it at…

Missing the Missing Summer 2012-04-15

Since I was a kid I’ve been reading stories about “The Year Without A Summer”. This was the summer of 1816, one year after the great eruption of the Tambora volcano in Indonesia. The Tambora eruption, in April of 1815, was so huge it could be heard from 2,600 km…

New Data, Old Claims About Volcanoes 2012-07-30

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Stacked Volcanoes Falsify Models 2013-05-25

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The Eruption Over the IPCC AR5 2013-09-22

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Volcanoes and Drought In Asia 2014-08-09

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Get Laki, Get Unlaki 2014-11-18

Well, we haven’t had a game of “Spot The Volcano” in a while, so I thought I’d take a look at what is likely the earliest volcanic eruption for which we have actual temperature records. This was the eruption of the Icelandic volcano Laki in June of 1783. It is claimed to…

Volcanoes Once Again, Again 2015-01-09

[also, see update at the end of the post] Anthony recently highlighted a couple of new papers claiming to explain the current plateau in global warming. This time, it’s volcanoes, but the claim this time is that it’s not the big volcanoes. It’s the small volcanoes. The studies both seem to…

Volcanic Legends Keep Erupting 2015-07-22

Once again, Anthony has highlighted a paper claiming that volcanoes have great power over the global temperature. Indeed, they go so far as to say: “From the reconstruction it can be seen that large eruptions, such as Mount Tambora in 1815, or clusters of eruptions, may …

Why Volcanoes Dont Matter Much 2015-07-29

The word “forcing” is what is called a “term of art” in climate science. A term of art means a word that is used in a special or unusual sense in a particular field of science or other activity. This unusual meaning for the word may or may not be …