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« Climate cuttings 54 | Main | New Scientist on significance »

Taking potshots at Plimer

An article in EOS by Terry Gerlach of the US Geological Survey takes aim at Ian Plimer's arguments about the contributions of volcanos to the carbon budget.

Which emits more carbon dioxide (CO2): Earth’s volcanoes or human activities? Research findings indicate unequivocally that the answer to this frequently asked question is human activities. However, most people, including some Earth scientists working in fields outside volcanology, are surprised by this answer. The  climate change debate has revived and reinforced the belief, widespread among climate skeptics, that volcanoes emit more CO2 than human activities [Gerlach, 2010; Plimer, 2009]. In fact, present-day volcanoes emit relatively modest amounts of CO2, about as much annually as states like Florida, Michigan, and Ohio.


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Reader Comments (18)

An interesting paper.

Whilst I claim no expertise in Vulcanology, nothing here convinces me that we have more than a hazy notion of how much CO2 is emitted by volcanic vents in the deep oceans.

He may well be right that human CO2 emissions are greater than volcanoes.

But it is interesting that he doesn't make the expected claim that there is evidence that CO2 emissions are a problem.

The fact that there isn't any evidence doesn't usually stop them.

Jun 15, 2011 at 7:23 AM | Unregistered CommenterMartin Brumby

A quick reading of this paper... His arithmetic looks right and his assumptions reasonable.
I'm a big fan of both Ian Plimer and his book, which I have read thrice. BUT - it does give the impression of being hastily produced (I mean some of the text body, not the diatribe at the end, which I agree with thoroughly, by the way) and I do think it suffers from that.
But, like Martin, at least Gerlach avoids the "anthropogenic" warming issue.

Jun 15, 2011 at 8:12 AM | Unregistered CommenterLevelGaze

What about the dust that errupting volcanoes put into the atmosphere. This shading/cooling effect must also be taken into account. The paper only majored on CO²; we need the whole story.

Jun 15, 2011 at 8:13 AM | Unregistered CommenterJohndeFrance

Are there any studies that separate the different sources of carbon dioxide in the atmosphere with a sound methodology? The usual carbon budget papers are just too vague to believe.

Jun 15, 2011 at 8:25 AM | Unregistered Commenterdahuang

As I've posted here and elsewhere, there is, as far as I know, only one volcanic seep in the world that is 100% captured: Lake Nyos, the site of the deadly CO2 release in 1986. The Lake Nyos seep emits approx. 187 million SCF per year. [NB: Other sources say 700 million SCFY. I base my number on calculations from figures contained in Schmid, Halbwachs, & Wuest (2006)]:

There are estimated to be 3 million subsea volcanic vents:

Thus from estimates of the Lake Nyos vent, the worldwide CO2 from volcanic sources could be as high as 30 GT of CO2/year, not counting land volcanoes. Compare that to the mere annual 0.13 to 0.23 GT estimated in Wankerpedia. (The NOAA Carbon cycle chart doesn't even show volcanic CO2.) Once again, the science is NOT settled and may be significantly in error.

Jun 15, 2011 at 9:18 AM | Unregistered Commenterjorgekafkazar

We are not even close to accurately estimate CO2 from volcanoes and other natural inputs. This non-anthropogenic CO2 input is not only much larger than anthropogenic but also variable. Its variations are likely larger than total of anthropogenic CO2.

Jun 15, 2011 at 9:39 AM | Unregistered CommenterEdim

If you are a follower of EM Smiths blog he from time to time does a piece on the possible correlation between the suns activity and seismic and volcanic activity. In essence it is that when the sun goes quiet seismic activity increases and this is followed but an increase in Volcanic activity. Are we seeing the first signs of this trend already. And given that CO2 is a big part of what comes out of a volcano how much is coming out of the Chilean volcano right now. It seems to be causing disruption over a far wider area than the Iceland eruptions caused.

I like others on this blog do not accept that we know what comes out of all the volcanoes, and once more it takes some leap of faith to think that we contribute more CO2 to the atmosphere than all the worlds volcanoes. Just because we don't measure it directly is not reason to dismiss it.

Jun 15, 2011 at 10:44 AM | Unregistered CommenterPeter Geany

I remain agnostic as to whether volcanic sources of CO2 are significant, but I generally also feel there is no profit in arguing (or "denying") the anthropogenic origin of the bulk of the increase in CO2 - after all, we do emit quite a lot of the lovely plant food!

Far better in my view to point out the lack of correlations between CO2 and temperature over the past century, the minuscule amount of the resulting warming, and the lack of evidence that current temperature trends are in any way outside the range of natural variation. After that one can go on to the shortcomings of climate models, the poor quality of the science backing alarmism, and the lack of any logical connection between rising temperatures and the economically insane policy prescriptions touted.

Conceding that we caused the CO2 levels to increase just saves time for arguing the important points. It also probably happens to be true, which should be the only reason needed anyway.

Jun 15, 2011 at 10:57 AM | Unregistered CommenterPeter Wilson

We have been discussing vulcanism here for quite some time. Please join in!

Jun 15, 2011 at 11:19 AM | Unregistered Commentermarchesarosa

"Oceanographers Hillier and Watts (2007) surveyed 201,055 submarine volcanoes. From this they concluded an astounding total of 3,477,403 submarine volcanoes must reasonably exist worldwide. They based this finding on the earlier and well-respected observations of Earth and Planetary Sciences specialist, Batiza (1982) who found that at least 4 per cent of seamounts are active volcanoes."

They even pulbished their data:

Jun 15, 2011 at 3:32 PM | Unregistered CommenterBruce

I know little about volcanoes, except that it seems prudent (to me) to stay as far away from them as is practical, but for us Kiwis, that's often not very far. Having seen at first hand some of the enormous geographic features such as Lake Taupo that were formed quite abruptly by volcanic activity, respect for them seems to be in order.
Considering how little is known about how many volcanoes sit on the sea floor pushing out unknown volumes of emissions, arguments about whether the author's arithmentic is correct seem somewhat irelevant to me.

Jun 15, 2011 at 3:38 PM | Unregistered CommenterAlexander K

My self do not know the anwser about CO2 by humanity versus volcano output is more but would like to know how they know just how much CO2 is actually spewed out compared to humanity, Guesstimates is the only anwser i have. Does any here know how and where they come up with the figures?

Jun 15, 2011 at 6:27 PM | Unregistered Commentergrayman

Dr. Ian Plimer was the guest speaker at the Friends of Science 8th annual luncheon on May 16, 2011. His presentation in PDF format and a video of the talk is here:

On slide 27, he estimates the average land-volcanoe emits 5,000 t C-equivalent of CO2 per day. At 1500 active land-volcanoes, this is 7.5 million tC/day (tC means metric tonnes of carbon equivalent of CO2). He estimates submarine volcanoes emit 4 times as much, 30 million tC/d, giving a rough estimate of total volcanoes emissions at 37.5 million tC/d. (His slide is missing the "/day", 2 places, and "M" means millions).

The post above at Jun 15, 2011 at 9:18 AM says "Thus from estimates of the Lake Nyos vent, the worldwide CO2 from volcanic sources could be as high as 30 GT of CO2/year, not counting land volcanoes." I am not sure if the author meant GT C/year, but assuming this is indeed GT CO2/year, this is equal to 30000/3.667/365 = 22.4 million tC/day. Thus, Plimer's estimate at 30 million tC/day for submarine volcanoes is 34% higher.

Plimer's slide compares his estimate of total volcanic emissions of 37.5 million tC/day to human caused emissions of fossil fuels of about 20 million tC/d. The CDIAC shows total human caused emissions in 2008 was 8749 million tC of which 8363 million tC was from fossil fuels, equal to 22.9 million tC/day.

Jun 15, 2011 at 7:26 PM | Unregistered CommenterKen Grgory

Reading Gerlach's paper was analogous to watching a heavyweight boxer pummel his opponent on the ropes. His arguments did rely heavily on other estimates of global magmatism but geologists have thought long and hard about magma fluxes into the crust so unless it can be shown that all his referenced global volcanism calculations are in error, Gerlach holds the high ground. From that position Gerlach keeps laying haymakers on anyone suggesting that volcanism supplies more CO2 than humans. Probably time for Plimer to throw in the towel on this point.

Jun 15, 2011 at 7:38 PM | Unregistered Commenternvw

Who cares where the CO2 comes from? Climate sensitivity for CO2 is around 0.4-0.6 C per doubling, based on quite a few direct and indirect measurements. At that rate pCO2 could rise tenfold with no harm...which would be worth all of 2 C.

Jun 16, 2011 at 12:39 AM | Unregistered CommenterBruce of Newcastle

And wouldn't you know it, I just found Lindzen & Choi's new PNAS paper via Judith Curry's blog. Prof Lindzen has upped their estimate of 2XCO2 to 0.7 C, which means you'd have to go up to 2000 ppmv in the Earth's atmosphere to get a 2 C rise out of CO2.

I can see why NAS pulled out the whole set of torture instruments to (try to) stop publication. They seem to have failed, which I interpret as meaning the paper is about as watertight as any could be.

Now could someone get this through the thick skulls of our respective PM's please?

Jun 16, 2011 at 2:02 AM | Unregistered CommenterBruce of Newcastle
Here's a link to some badly done, and thoroughly misquoted papers including Gerlach's substandard analyses of submarine CO2. Since he gets quoted extensively by the USGS about man made versus volcanic exhalations, he's protecting his turf.
Gerlach's info and the others noted are all well worth reviewing.

Jun 16, 2011 at 6:13 AM | Unregistered Commentermikegeo

Some time ago Gerlach refuted Plimer's claim regarding the magnitude of sub-marine volcanic CO2 emissions, by stating that USGS monitors this aspect. I have extensively trawled the USGS web-site (which details their activities and projects) and found no evidence to support Gerlach's statement, viz that they monitor submarine emissions. If anyone can show me to be in error on this I would be grateful.

Jun 17, 2011 at 1:11 AM | Unregistered CommenterPeter O'Brien

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