Tag Archives: Volcanoes

Lots of new climate change science stuff

I just did an interview on Green Diva Radio, and talked about a lot of climate change science news. For those who want to see the sources, here is a quick summary:

On Friday, NASA and NOAA are expected to announce that 2014 was the hottest year on record. I had been planning to write an extensive blog post going into all sorts of details about how that works, how they calculate it, etc. But then the people at Climate Nexus wrote a post that would have blown mine out of the water with the detail and informtation provided in it. Go here to read this excellent post: 2014: Putting The Hottest Year Ever in Perspective.

More than one new paper has come out describing new work on melting glaciers, especially in the Antarctic. One of the papers is described by an author, John Abraham, in this blog post: The Antarctic ice sheet is a sleeping giant, beginning to stir. You can get to the original paper via a link in that blog post. Bottom line is that the polar ice sheets are melting faster and faster every time someone looks. There is also some interesting stuff about melting glaciers, gravity, and sea level rise. Very much worth a look.

There is also a new sea level rise curve. I’ve not looked at this so I have no comments on it, but you can see a write up here: A new sea level curve.

The first in a series of predictions for the 2015 Atlantic Hurricane seasons has come out: 2015 Hurricane Zone Predictions: Stronger Season with Three U.S. Hot Spots. Bottom line is that it will be a pretty average hurricane season, which, in turn, means more hurricanes and more severe hurricanes than during the last few years, which have been rather anemic. Which, by the way, is probably a side effect of climate change.

There has been some recent work confirming some earlier work, suggesting that a lot of “small” volcanoes have created a lot of dust contributing to cooling of the Earth’s atmosphere, slowing greenhouse gas caused warming. Despite what at lease one of these items says, we are now pretty sure that most of the surface temperature slowdown is because most of that heat is going into the ocean (see this), but volcanic dust has also made a contribution (as has the sun, being in a somewhat weak phase). So there are two things you should have a look at: Volcanoes may be responsible for most of the global surface warming slowdown and Small volcanic eruptions explain warming hiatus. Imma go out on a limb and guess that a little over 50% of the lack of warming (though it is warming, just slower) is from the ocean taking in more heat, the next biggest contribution is the volcanic dust, and a smaller but still two digit percentage (maybe) is from the sun. Feel free to challenge me on those numbers but do so with evidence please. I’ll be happy to see that estimate refined.

Volcanoes, Tree Rings, and Climate Models: This is how science works.

Mark Your Cosmic Calendar: 774/775

One wonders if anyone felt it. Did Charlemagne feel it as he led his forces across Pagan Saxon Westphalia, knocking down Irminsuls and making everyone pretend to be Christian or else? Did the people of Bagdad, just becoming the world’s largest city, notice anything aside from their own metro-bigness? Did the Abbasid Caliph Muhammad ibn Mansur al-Mahdi have the impression something cosmic was going on that year, other than his own ascendancy to power? Or was it mainly some of the Nitrogen molecules in the upper atmosphere that were changed, not forever but for an average of 5,730 years, by the event?

The bent tree like object is said by some to be the, or a, Irminsul, the "pagan" sacred object, destroyed by Charlemagne much as one might destroy a hypothesis, either with, or about, trees.
The bent tree like object is said by some to be the, or a, Irminsul, the “pagan” sacred object, destroyed by Charlemagne much as one might destroy a hypothesis, either with, or about, trees.
A long time ago, probably in our galaxy but kind of far away, a cosmic event happened that caused the Earth to be bathed in Gamma rays in AD 774 or 775. No one seems to have noticed. There is a mention, in 774, of an apparition in the sky that could be related, but talk of apparitions in the sky were more common back then, before they had certified astronomers to check things out. There is chemical and physical evidence, though, of the Gamma ray burst. The best evidence is the large scale conversion of stable Nitrogen isotopes into unstable Carbon–14 isotopes in the upper atmosphere. As you know, radioactive (meaning, unstable) Carbon–14 is created continuously but at a somewhat variable rate in the upper atmosphere. Some of that Carbon is incorporated, along with regular stable Carbon, into living tissues. After the living tissue is created and further biological activity that might retrofit some of the Carbon atoms ends (i.e., the thing dies) the ratio of radioactive Carbon to stable Carbon slowly changes as the radioactive Carbon changes back into Nitrogen. By measuring the ratio now, we can estimate how many years ago, plus or minus, the originally living thing lived and died.

But it does vary. Solar activity, nuclear testing, other things, can change the amount of Carbon–14 that gets produced. And, a cosmic event that happened in 774/775 caused the production of enough Carbon–14 to throw off the chronology by hundreds of years. This is seen in the close examination of Carbon in the tissue of trees placed in a tree ring chronology. For example:

Screen Shot 2014-07-29 at 2.00.05 PM

Original Caption: High-resolution radiocarbon ages, superimposed on annually resolved radiocarbon measurements from Japan and Europe (grey lines and crosses) as well as the IntCal calibration curve based on decadal samples (blue shading), re-sampled at 5 year intervals (light blue crosses). Radiocarbon ages (that is, using 14C, 13C and 12C isotopes) were determined at ETHZ with the MICADAS system.

See the inverted spike there? That is, apparently, gamma rays messing up the Radiocarbon chronology. Hold that thought.

Climate Change Is Hard

When volcanoes erupt, they typically spew crap into the air. Some of this material stays in the atmosphere for a while (called aerosol, but not your underarm deodorant exactly) which will in turn reflect sunlight back out into space prematurely. This causes cooling. It is essential to know how much cooling of the atmosphere happens from aerosols because this is a potentially important factor in global warming. The effect of aerosols caused by volcanoes or industrial activity is an important term in the big giant equation that puts all the different factors together to produce global warming (or cooling). It is important that climate models be able to accurately and realistically incorporate the effects of aerosols. If the science isn’t right on aerosols, climate models may not run true when aerosols are included.

Caldera of Mount Tambora.  When Tambora erupted in 1815 we experienced a year without a summer (1816). Tambora was small compared to many earlier volcanoes which may have produced a few summer-less years in a row.
Caldera of Mount Tambora. When Tambora erupted in 1815 we experienced a year without a summer (1816). Tambora was small compared to many earlier volcanoes which may have produced a few summer-less years in a row.
And indeed there is an apparent problem. When climate models are run and include aerosols, and the results are compared with real life data where we have good proxyindicators of past climate, the model predictions and the real life measurements don’t line up when aerosols are involved at any significant level. A big volcano goes off, but the proxy record consisting mainly of things like tree rings doesn’t show the level of cooling models predict. This has titillated denialists, as you might imagine, because it shows how the science has it all wrong and the only way to truly understand the climate change is to spend hours in the basement with your spreadsheet and a good internet connection, like Galileo would have done.

In fact, this was an interesting problem that needed to be addressed. The modeling methods had to be wrong, or the paleodata had to be wrong, or something had to be wrong.

In 2012 Michael Mann, Jose Fuentes and Scott Rutherford published a paper in Nature Geoscience proposing a hypothesis to explain this discrepancy. The problem was that when a known volcano went off, the tree ring record in particular tended to show only an anemic result. Volcanoes that were thought to totally mess up the weather seemed to have little effect on trees. This even applied to volcanoes which were very directly observed in recent times, when we know there was an effect because people were putting on sweaters and measuring things with actual thermometers.

Mann et al proposed that rather than having little effect on tree growth, the volcanoes had a huge effect on tree growth. What was being seen by the Dendrochronologists (tree daters, like tree huggers but more serious) as a normal, average growth ring at the time of a volcanic eruption was actually the ring for the next year in line; they were missing, understandably, one or more growth rings. The volcano goes off, the trees don’t grow at all. (The masquerading ring would typically be the year before the missing ring since dendrochronology is done backwards, since we know what year it is now.)

You don’t have to imagine a year in which no tree grows ever anywhere to accept this idea. The trees being used as temperature proxies are more the sensitive type. They respond to temperature changes by growing more or less (warmer vs. cooler). Trees that don’t do this are not chosen for study. This has to do with the species and the setting the tree grows in, combining to make temperature the key limiting factor most years, so that growth ring width reflects temperature more than any other factor. So yeah, when it gets very cool because of a big-ass volcanic eruption, one of those “year with out a summer” deals, the very sensitive trees respond by not growing at all that year. They may have a growth period of a few weeks, but trees don’t simply lay down wood every day they are biologically acvite. They usually start with leaves, then many move on to reproduction, and once they have finished reproducing, have a cigarette, wash up, whatever, they may lay down wood or roots. (Different species have different patterns). So a very short growing season can mean no ring at all. If a really bad nuclear-winter-esque volcano happens this may go on for a few years. This leads to the growth ring corresponding to the year of the volcano simply not being noticed by the dendrochronologists, with a different year standing in. Over time the record can be thrown off by several years, if there are a few volcanoes and one or more of them affects growth for more than one year.

So two things happen. Years with a very strong cold signal are lost entirely, and the record is quasi-randomly offset by a few years in some but not all tree records (because some will be thrown off while others are not) so the collective record gets out of alignment. A strong uptick in the signal (the zero growth year) does not contribute to the paleoclimate squiggle of temperature at all, and the other possibly contributing years (after the worst is over) are moved around in relation to each other and average in with less cold years. It’s a mess.

Consider the following made up numbers representing temperature over time. The top table is the hypothetical raw data of tree ring growth in relation to temperature across a very strong cold anomaly as might be caused by a massive volcanic eruption. Depending on the tree, there is one or more years of zero growth. The lower table is the same set of numbers but with the earlier years (top) shifted down to cover the zeros, because that is what would happen if a dendrochronologist was looking at the rings from more recent (bottom) to oldest; there would just be this void and it would be filled with the next data in line.

Screen Shot 2014-07-30 at 7.20.34 PM

Here are the same data graphed showing a clear anomaly in the top chart, but the very clear anomaly utterly disappears because of missing rings and shifting sequences in the lower chart. This is an existential problem for ancient climate events. I squiggle therefore I am.

Screen Shot 2014-07-30 at 7.16.41 PM

Mann Et Al proposed adjustments to the record of proxyindicators of temperature that accounted for missing tree rings at the time of major volcanic events. They made a good case, but it was a bit complicated and relied on some fairly complicated modeling.

Since the publication of Mann et al there has been quite a bit of back and forth between the climate modelers and the dendrochronologists. I’ve assembled a list of publications and blog posts below. I’ll only very briefly summarize here.

The dendrochronologists had a bit of an academic fit over the idea that they had missed rings. Understandably so. As an archaeologist, I’m partly trained in dendrochronology. There was actually a time when I considered making it my specialty, so I had read all the literature on the topic. I can tell you that missing rings was a serious concern, and taken seriously, and seriously addressed. Seriously, there’s no way modern dendrochronologists would totally miss an entire year’s growth rings. They had ways of dealing with missing rings.

The thing is, it is actually possible to miss rings. Here’s why. The assumption in Dendrochronology is that rings can be missed (or for that matter, added) for reasons that allow for correction by cross dating growth ring sequences with other trees or even other samples in a single tree. A particular part of a tree can be missing a ring while another is not (especially vertically; the lower part of a tree grows last in many species), or some trees in an area may be missing a ring, but others have that growth ring. This assumption is probably almost always valid; missing rings can ben adjusted for by cross checking across samples. But, if all of the trees of a given species and sampling area have one or more missing rings because of a major volcanic event, that won’t work. But this is not something Dendrochronologists are used to.

2 + 2 = 774/775

Eventually Mann and his Colleagues put two and two together and realize that the Dendrochronologists had a way to test the hypothesis that would not rely on fancy dancy climate modeling techniques, and that would potentially allow a better calibration of the tree growth ring record for certain time periods. It was that Gamma ray burst.

That moment in time is a clear marker. Any system involving Carbon–14 spanning this time interval should show the spike. Well, what about tree ring records that span both a major volcano and the 774/775 event? If Mann et all are right, an uncorrected tree ring record would show a lack of correspondence of any spike at 774/775. But, if missing rings are assumed for sensitive tree records at the time of the volcano, and the tree ring sequence for those trees shifted, perhaps the records will line up. That would be a test of the hypothesis.

And this is the gist of a letter to Nature from Scott Rutherford and Michael Mann. Very simply put, Mann and his colleagues took this graph, from an earlier paper:
Screen Shot 2014-07-30 at 8.11.52 PM
And changed it to this graphic which shows mainly (see caption) the tree ring sequences that span both the 1258 volcanic eruption, which was a big one, and the 774/775 event.
Screen Shot 2014-07-30 at 8.11.35 PM
This is a gauntlet, being respectfully thrown down. Mann et al erected a hypothesis, that missing tree rings are virtually universal in large parts of the dendrochronological sample for some events, were not accounted for in the tree ring chronology, and have thus messed up the tree rings as a proxyindicator for temperature. Various attempts to knock it down have not worked out. Now, Mann has himself provided an excellent way to assail his own idea. It is now up to the tree ring experts to try to knock this hypothesis down. I suspect Charlemagne might have had an easier time knocking down the Irminsul.

I asked Michael Mann how he felt about this latest development in the ongoing saga of the missing (probably) growth rings. He said, “I’m very pleased that we’ve reached some level of reconciliation with our dendroclimatology colleagues: there’s an objective test that is available to determine if there are indeed missing rings in some of the regional chronologies as we have speculated to be the case. I look forward to seeing the results of those tests. We proposed a hypothesis, other scientists were skeptical of the hypothesis, and now there is a way forward for testing the hypothesis. In the end, a fair amount of good science will have been done, and we will have learned something. This is the way science is supposed to work.”

This is going to make a great Master’s thesis for someone.

As promised, a list of writings on this topic, organized by date:

2012 Mann, M.E., Fuentes, J.D., Rutherford, S., Underestimation of volcanic cooling in tree-ring- based reconstructions of hemispheric temperatures, Nature Geoscience, doi:10.1038/NGEO1394, 2012. Press release here.

2012 Mann Et Al. Global Temperatures, Volcanic Eruptions, and Trees that Didn’t Bark. Real Climate.

2012 (November) Kevin J. Anchukaitis, Petra Breitenmoser, Keith R. Briffa, Agata Buchwal, Ulf Büntgen, Edward R. Cook, Rosanne D. D’Arrigo, Jan Esper, Michael N. Evans, David Frank, Håkan Grudd, Björn E. Gunnarson, Malcolm K. Hughes, Alexander V. Kirdyanov, Christian Körner, Paul J. Krusic, Brian Luckman, Thomas M. Melvin, Matthew W. Salzer, Alexander V. Shashkin, Claudia Timmreck, Eugene A. Vaganov & Rob J. S. Wilson. Tree rings and volcanic cooling. Nature Geoscience 5, 836–837 (2012) doi:10.1038/ngeo1645

2012 (November) Mann, Fuentes and Rutherford Reply to ‘Tree rings and volcanic cooling’. Nature Geoscience. 5, 837–838 (2012) doi:10.1038/ngeo1646

2012 Gavin at RealClimate Responses to volcanoes in tree rings and models

2012 Esper et al. Testing the hypothesis of post-volcanic missing rings in temperature sensitive dendrochronological data Dendrochronologia. Volume 31, Issue 3, 2013, Pages 216–222

2012 Esper et al. European summer temperature response to annually dated volcanic eruptions over the past nine centuries. Bulletin of Volcanology. June 2013, 75:736

2013 George et al. The rarity of absent growth rings in Northern Hemisphere forests outside the American Southwest. Geophysical Research Letters. 40(14) 3727-3731.

2013 D’Arrigo et al. Volcanic cooling signal in tree ring temperature records for the past millennium Journal of Geophysical Research: Atmospheres. Volume 118, Issue 16, pages 9000–9010, 27 August 2013

2014 Jull et al. Excursions in the 14C record at A.D. 774–775 in tree rings from Russia and America. Geophysical Research Letters. Volume 41, Issue 8, pages 3004–3010, 28 April 2014

2013 Mann, Michael, Scott Rutherford, Andrew Schurer, Simon Tett, Jose Fuentes. Discrepancies between the modeled and proxy-reconstructed response to volcanic forcing over the past millennium: Implications and possible mechanisms. J. of Geophysical Research: Atmospheres, Vol 118, 7617–7627.

2014 Büntgen. Et Al. Extraterrestrial confirmation of tree-ring dating. Nature Climate Change 4: 404-405.

2014 [Rutherford, Scott and Michael Mann. Missing tree rings and the AD 774–775 radiocarbon event](http://www.nature.com/nclimate/journal/v4/n8/full/nclimate2315.html?WT.ec_id=NCLIMATE–201408]. Nature Climate Change. Vol 4, August 2014.

First it was bear paternity tests, now it is volcano monitoring

When will the madness end? When the Republicans dry up and blow away, of course.

In the Republican response to Obama’s State of the Union 2.0 address, by Bobby Jindal, governer of Louisiana, we heard this:

“Instead of monitoring volcanoes, what Congress should be monitoring is the eruption of spending in Washington, D.C.,”

The reason why volcanoes have been picked out of some speech writer’s anal sphincter zone is because they erupt and they wanted the metaphor. Or because Jindal believes he has no volcanoes in his state (but he would be wrong) or because of some other rhetorical reason. This is the same exact device as the bear paternity test complaint we heard spewing forth from the Hypocrite McCain and the Moron Palin during the campaign.

Maria Brumm is talking about it: “Something Called Volcano Monitoring”: Bobby Jindal Needs a Geology Lesson

Do Republicans (or moderates who don’t have a kneejerk anti-Republican reflex) also feel like he’s talking to the nation as though we were all kindergarteners? I was flabbergasted, but I don’t know how to properly account for my rather strong political biases here.

Scientific American is talking about it: Bobby Jindal and volcano monitoring: What was he talking about?

“Why does Bobby Jindal think monitoring volcanoes is a bad thing for the government to be doing?” Nick Baumann writes in Mother Jones. “There doesn’t seem to be any immediate way for private enterprise to profit from monitoring volcanoes (maybe selling volcano insurance?), but there is obviously a huge public benefit from making sure volcanoes are monitored: warning people if a volcano is going to erupt. Isn’t that obvious?”

OK, so clearly the Republicans are mean spirited knowledge-free hypocrites and Jindal is therefore a great spokesperson (or should I say spokesman) for them. And Maria and Sciam are right. But everyone is missing the true irony here.

The true irony is this: Remember New Orleans? Remember Katrina? Scientific research on disaster prediction predicted Katrina and its effects on New Orleans perfectly. PERFECTLY I SAY!!!! But those predictions were ignored (and continue to be ingnored).

But scientific monitoring does not always get ignored. The roads are laid out in many places with consideration for evacuation in the case of certain events. As Maria pointed out, large numbers of lives and dollars were saved from the effects of the eruption of Mt. Pinatubo … which was a (say it with me now) a volcano … Because. Of. Scientific. Monitoring. And so on. Katrina is seen as an immeasurably large disaster of public policy because the clear warnings from the scientific research were ignored. Had they not been ignored, we would not be talking about this.

Teh Irony, then, is that the biggest disaster happened in the most third world of the states because of the boobs that run that place, and Bobby Jindal is Head Boob. And he is telling us what we need to do regarding scientific monitoring of potential natural disasters.

The metaphors! They are everywhere!

The fox is giving us a lesson on how to close the chicken coop. The farmer who left the barn door open is telling us about how to take care of your horses. The pot is explaining to the kettle how to clean off the soot. Chicken little is giving us a lesson on framing. The little Dutch boy is taking piano lessons. The Republican is telling us how to manage scientific priorities.

Oh, no, wait, that last one is not a metaphor. It is a TRAGEDY!!!!