Monday, November 19, 2012

Solution is Sometimes the Solution to Pollution

There has been quite a bit of worry about what happens when the methane hydrates on the Arctic shelf go blooie, but a factor not thought of by many is that since these hydrates are underwater, a fair amount of the methane will never reach the surface, but will first go into solution in the sea water, and later be oxidized to CO2, hydrogen carbonate and carbonate ions. 

The same issue confronts anyone (Ian, Ian Plimer, are you out there), who rants about all of the carbon dioxide coming from underwater volcanoes.  In point of fact, you read it here on Rabett Run, that if such volcanoes really were the source of so much CO2, the easy mark would be to go look for acidic plumes in the ocean.  Plimer's hound of the Baskervilles as it were, because they are not found. 

Biastoch, et al (eleven of them, including Latif, and Wallman at  the University of Kiel, have thought about the fate of the methane hydrates, and in an article entitled "Rising Arctic Ocean temperatures cause gas hydrate destabilization and ocean acidification" conclude that the major effect will be a decrease of pH, near the Arctic Ocean coasts.

Since the Arctic has and will be warmed considerably, Arctic bottom water temperatures and their future evolution projected by a climate model were analyzed. The resulting warming is spatially inhomogeneous, with the strongest impact on shallow regions affected by Atlantic inflow. Within the next 100 years, the warming affects 25% of shallow and mid‐depth regions containing methane hydrates. Release of methane from melting hydrates in these areas could enhance ocean acidification and oxygen depletion in the water column. The impact of methane release on global warming, however, would not be significant within the considered time span.
Remember that pH is a logarithmic scale so a change of .25 on the pH scale is an increase of ~75% in acidity.


David B. Benson said...

Maybe don't want to go bathing there?

Lewis Cleverdon said...

Is that "50% of methane hydrates released within 100 years" perchance calculated from the same models that caused the IPCC AR4 to mis-forecast the loss of summer sea ice - by about 100 years ?

If these massive methane stocks are going to be reliably reacted in sea-water to have no effect on warming, then what exactly has been happening in massive and expanding areas of the Laptev Sea in recent years ?

Sychronised hallucinations ?



Anonymous said...

Having not RTFR I might be reinventing the wheel, but I think that one of the considerations would be how the clathrates change phase. If it happens abruptly one would expect rather bigger bubbles that might not dissolve, and if it happens explosively in an area there would be little dissolution at all.

At least that's what I'd expect.

Bernard J. Hyphen-Anonymous XVII, Esq.

Hank Roberts said...

> what exactly has been happening

Aircraft, even some passenter aircraft, routinely carry CO2 sensors, and the Japanese satellite ought to be producing data fairly soon, so even if the Russians aren't publishing whatever they've found out -- if a trend is detectable in methane in the air -- someone will make it public.

Publication takes a very long time. If they don't have good data or don't want to make it public -- it's hard to know what has been happening.

Peter Ward and Eric Steig were looking into previous anoxia events correlated with xtinctions; this is the only publication I've seen mentioned so far

Ward, P.; Haggart, J.; Mitchell R.; Kirschvink, J.; Tobin, T.. "Integration of macrofossil biostratigraphy and magnetostratigraphy for the Pacific Coast Upper Cretaceous (Campanianâ Maastrichtian) of North America and implications for correlation with the Western Interior and Tethys," Tethys Bulletin of the Geological Society of America, January/February, v.124, 2012, p. 1.

Jeffrey Davis said...

It's hard to extract methane from clathrates. If it were easy, energy companies would be mining them instead of fracking. Think about that: getting bulk CH4 out of deep rock with steam and solvents is easier than getting bulk CH4 from clathrates.

Yes, there are places where CH4 is just bubbling up, but the net effect of this bubbling up hardly moves the atmospheric concentration of CH4. The atmosphere is a real big place.

CO2 is hobgoblin enough, fully capable of bringing civilizations down upon our heads. We don't need a CH4 hobgoblin on speed and steroids to scare us.

Aaron said...

Many the gas wells in Siberia pull gas from decomposing clathrates. (Decomposing clthrates gave old and depleted gas fields a second lease on life.)

The problem is not converting the clathrates into gas, the problem is controlling the rate of decomposition and recovering the gas in an unconfined ocean environment. Companies lose their permits if the sea around their wells is boiling with CH4.

Alastair said...

It's not just their permits they can lose if the sea boils with methane. The methane in the sea will reduce the buoyancy of their ship and sink it. That may be what happened in the Bermuda Triangle, and the North Sea.

And a boiling sea is not the worst case. A blazing sea is also possible!

David B. Benson said...

Bernard J. Hyphen-Anonymous XVII, Esq. --- Yes, when that happens in the ocean the result is called a blow out. I don't know of an actual explosions but the scar left on the sea floor is certainly an impressive (not very deep) crater complete with a rim.

WhiteBeard said...

Somewhat OT news on continuing testing of in situ carbon dioxide replacement of methane in calthrates:

Fairly good links below (the 1st one in the More Info sidebar relates the project above):

And more generally, but personally not having RTFM:

J Bowers said...

Seems relevant (H/T Ari Jokimalki):

'Sea ice in the Arctic Ocean: Role of shielding and consumption of methane'. He et al (2012).

Anonymous said...

-- Horatio's versification of Eli

Is solution
For ablution
Of pollution

Holly Stick said...

"Heroes of Science": lacks most women, etc., but still a cool idea:

Hank Roberts said...

Has this sea level change projection made it into the other models yet?

"... Reporting this week (Thursday 10 May) in the journal Nature, scientists from ice2sea highlight how future climate change will drive considerably greater quantities of warm water toward Antarctica, and increase the loss of ice from the continent.

Researchers from the Alfred Wegener Institute (AWI) in Germany and UK Met Office Hadley Centre completed a series of experiments for ice2sea – a major EU FP7 programme that aims to improve projections of future sea-level rise. In these, models of the global ocean were driven with projections of climate produced for two possible carbon emission scenarios. A common feature in all the simulations is a massive increase in melt in an unexpected part of Antarctica, the Filchner-Ronne Ice Shelf. ..."

david lewis said...

David Archer, who has studied this issue in depth, explained his views in January 2012 on RealClimate.