Wednesday, March 19, 2008

Gassing it up

Eli has had an idle thought. If you google "Sheep Mountain CO2 strip bark" you will hit the motherwave of denialist froth centered on the dendrology of very old trees high up in the Sierra sampled by Graybill. You could also add Campito, which is a bit to the north. Both can be found in the International Tree Ring Data Bank housed on line by NOAA. Now, being a curious bunny, Eli wanted to see where this was, and he had a map from "Trends in twentieth century tree growth at high elevations in the Sierra Nevada and White Mountains, USA from Bunn, Graumlich and Urban to go on. The area looked familar, so he looked it up on Google maps, and wadda you know, Sheep Mountain is right across from the Long Valley Caldera.

This may not mean much to the sheltered readers of this blog, but veterans of the CO2 comes from volcanoes nonsense will recognize Long Valley as the largest geological source of CO2 in the US, and pretty close to being the largest geological source anywhere until the next Pinatubo goes off (which may be at Long Valley:(.

A lot less than a zillion tailpipes but not zilch. Making the not so dumb assumption that winds move the CO2 from the caldera west up onto the mountain the case for CO2 fertilization looks pretty strong. OTOH, the level there could be a lot higher than normal and could have been so for a long time.


11 comments:

Orange said...

60 kilometers seems like a long way for CO2 to travel and remain significantly higher in concentration. The map provided on the link showed pretty rapid drop off of CO2 flow after just 200 meters or so.

EliRabett said...

That's the CO2 emissions from the ground, not the mixing ratio in the air. In short it is the source term.

Anonymous said...

It should be possible to look at the rings at about 250 years ago (time of the last eruption) to see if the ring width changed then.

http://pubs.usgs.gov/fs/fs172-96/

"Past eruptions at Mammoth Mountain, such as the phreatic (steam blast) eruptions that occurred about 700 years ago on the volcano’s north flank, may have been accompanied by CO2 emissions. Scientists think that the current episode of high CO2 emissions is the first such activity on the mountain for at least 250 years because the oldest trees in the active tree-kill areas are about that age. Carbon-isotopic analyses of the annual growth rings in trees near the margins of the tree-kill areas imply that the gas-emission rate reached a peak in 1991, subsequently declined, and then has been relatively stable since about 1996."

Anonymous said...

I’m puzzled about the purpose of this posting. It doesn’t appear to be accurate or really mean anything. Could you clarify?

1) You indicate: “Long Valley as the largest geological source of CO2 in the US”. However, the article that this statement links to does not indicate that Long Valley is the largest geological source of CO2 in the US. A further link at that USGS website http://pubs.usgs.gov/fs/fs172-96/ indicates about 300 tons of CO2 emissions per day.
This is not really very much when compared to Yellowstone Caldera http://www.agu.org/pubs/crossref/2003/2002GC000473.shtml (yeah, I’ve paid my $20) at ~45 Kt per day. Why indicate long Valley is the largest?

2) How does this relate to bristlecones in the White Mountains? They are about 60 km away and dispersion is an effective process. Serendipitously, the USGS web site has another web page http://volcanoes.usgs.gov/About/What/Monitor/Gas/Mammoth.html that shows airborne detection of CO2 at an altitude of 2,900-3,200 m (about the elevation of the White Mountain bristlecones ( http://sonic.net/bristlecone/WhiteMts.html ). The concentration goes to background at a distance of ~10 km from Mammoth Mountain with the wind blowing to the south-southwest (same direction as White Mountain bristlecones) so none of this excess CO2 seems to get to the trees.

Anonymous said...

I had no idea CO2 was so dangerous. No more snowcamping for me. But the real killer is dihydrogenmonoxide

www.dhmo.org/

Alan

Laser Potato said...

Har har har, Alan. Too bad for your analogy that C02 is actually TOXIC. Choke damp and fire damp have claimed the lives of countless miners. Also, there's the Lake Nyos incident: http://www.snopes.com/horrors/freakish/smother.asp

Anonymous said...

I had already followed Eli's link and was surprised to see this:
CURRENT HAZARDS: Inhaling high concentrations of carbon dioxide gas can cause dizziness, unconsciousness, and death. It is hazardous to dig holes in and around areas where the trees have been killed by carbon dioxide gas. Natural collapse pits that develop on the northwestern shore of Horseshoe Lake as the lake level declines contain high CO2 concentrations - extreme care should be taken to prevent children and dogs from entering these pits or digging up loose soil that has been placed in the pits. Care should also be taken to avoid a crack 1-2 feet wide that extends from the lake onto the west shore. Do not lie face down on the ground anywhere near Horseshoe Lake or the tree-kill area.
As snow levels accumulate in the winter, toxic levels of CO2 can develop in tree wells, around buildings, and immediately below the snow surface in areas of high CO2 emissions. Pay serious attention to signs warning of CO2 hazards.

But the dhmo website is a good spoof! No?

Alan

Anonymous said...

Laser Potato

Re Lake Nyos disater of 1986.

Thanks for link. See also Wikipedia: Lake Nyos

It is believed that up to a cubic kilometre of gas was released. Because pure CO2 is denser than air, the gas flowed off the mountainous flank in which Lake Nyos rests and down two adjoining valleys in a layer tens of metres deep, displacing the air and suffocating all the people and animals before it could dissipate. ... The level of the lake dropped by about a metre, representing the volume of gas released.

Alan

Anonymous said...

You know climate science would get a better reputation if its practitioners moved beyond the arm waving stage of theorizing. Anything and everything seems to be posited as a reason for any difficulty

Anonymous said...

Further to my last comment, I should have added a note about the irony of a below arm waving level piece, such as this, containing a snide remark about "froth" coming from others

EliRabett said...

Paw waggling. Please be accurate.

However, you do note that this conjecture was not repeated a thousand times in a thousand posts with a lot of high dudgeon and no sense of humor. A little bit of froth on the caldera is ok, a blog full of it is not.