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kristopher

(29,798 posts)
6. Once more: McPhersons methane catastrophe
Sat Jul 1, 2017, 03:43 AM
Jul 2017

Once more: McPherson’s methane catastrophe
01/08/2015 BY SJ
753
For better or worse, I want to briefly return to Guy McPherson’s claims of human extinction within 20 years via a climate catastrophe. Guy is aware of my criticism of his argument, but has declined to consider the problems I pointed out (instead choosing to accuse me of being paid to disagree with him, which would be news to my bank account). Because I’ve seen him reduce his climate claims to the same two keys a few times now, I thought it might actually be worth singling them out for detailed inspection (even though both are mentioned in my previous post, which was a little overwhelming). I’ll try to keep this simple, but the desire to be thorough can make that a challenge…

(Runaway) Train to Siberia

The first claim is that there is an incontrovertible, rapidly accelerating release of methane from the Arctic. (Example here.) McPherson ascribes this to a destabilization of methane hydrates (also called clathrates) in the sediment beneath the Arctic seafloor. Ostensibly, this is based on the research of a team including Natalia Shakhova that has been studying methane release along the East Siberian Arctic Shelf, but McPherson’s claims about that research come from posts on the “Arctic News” blog. This blog, run by a retired petroleum geologist named Malcolm Light and someone writing under the name of Sam Carana, posts a great deal of strange and unscientific claims about earthquakes and methane in the Arctic.

Specifically, McPherson points to a post there interpreting the Shakhova et al. research as indicating an exponentially-growing release of methane from the East Siberian Arctic Shelf. Apart from the fact that two data points can’t tell you there’s an exponential trend (rather than, say, a straight line), this also makes the mistake of assuming that there are actually two data points! What really happened is that the Shakhova group tried to estimate the total annual emission of methane from the East Siberian Arctic Shelf after observing some plumes above focused release points. (It’s not yet known if these releases have increased recently— the submerged permafrost has been thawing for thousands of years, since sea level rose coming out of the last ice age.) A couple years later, they published a new estimate based on expanded observations. This was a revision of their earlier estimate, now that they had more data in hand. Sam Carana treated these two estimates as independent numbers representing a time series— asserting that the emission of methane had more than doubled in just a few years. From there, Carana extrapolated to predict that emissions would increase about 1,000 times over by 2040. As a result, he/she predicts a cartoonish increase in the global average temperature of 11 C by 2040. (Actual climate models, on the other hand, project a temperature increase of around 4 C by 2100 if we fail to reduce greenhouse gas emissions— and that’s a deeply troubling scenario.)

Actual measurements of methane in the atmosphere don’t show any such sudden, accelerating spike, and climate scientists don’t believe anything like this “clathrate gun” scenario is underway. The Arctic News Blog obsesses over some satellite measurements of methane in the Arctic, believing that they support the claim of runaway methane emissions. (A researcher who worked on validating that satellite dataset confirmed to me that the raw data the blog is using hasn’t been through any quality control algorithm, and that the instrument hasn’t been validated for some of the kinds of conclusions Carana wants to draw.) By showing that some recent measurements of methane in the Arctic are above the global trend, they believe they are demonstrating a sudden increase. This is misguided, because the Arctic is always above the global average. That’s why we calculate averages. If you measure CO2 in the smokestack of a coal-burning power plant and find that it’s much higher than the global average from last week, you can’t conclude that is CO2 suddenly spiking globally. That sort of apples-to-plastic-oranges comparison is meaningless.

So when McPherson claims that “the clathrate gun has fired“, he does so without any evidence whatsoever. Rather, he relies on elementary mistakes made by a blogger who doesn’t appear to understand the science. Not data. And not published research. Not only do climate scientists not think that such a thing is underway, most don’t think it’s likely to be a worry this century....

More at: https://fractalplanet.wordpress.com/2015/01/08/once-more-mcphersons-methane-catastrophe/

Let that second paragraph sink in:
"The first claim is that there is an incontrovertible, rapidly accelerating release of methane from the Arctic. (Example here.) McPherson ascribes this to a destabilization of methane hydrates (also called clathrates) in the sediment beneath the Arctic seafloor. Ostensibly, this is based on the research of a team including Natalia Shakhova that has been studying methane release along the East Siberian Arctic Shelf, but McPherson’s claims about that research come from posts on the “Arctic News” blog. This blog, run by a retired petroleum geologist named Malcolm Light and someone writing under the name of Sam Carana, posts a great deal of strange and unscientific claims about earthquakes and methane in the Arctic."

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