Sunday, March 11, 2012

Time to call it climate change and acidification

I think ocean acidification should stop being considered just one of the effects of GHGs and give it top-line billing.  That the oceans are acidifying faster than anytime in the last 300 million years received moderate press (I think Wired had the best pop-science coverage, would love links to other good pieces).  People had to read fairly deeply into coverage to read that we only stop at 300 million years because there's no decent geological record before then.  Those denialists who point out that temperatures were warmer than present way back when the earth was a growing ball of lava might not have an irrelevant precedent to point to in this case.

Not only are the oceans acidifying faster, they're doing at a much faster pace, with pleasant information like this at the link:

The boundary between the Triassic and Jurassic included a large increase in atmospheric CO2 (adding as much as 1,300 to 2,400 ppm) over a relatively short period of time, perhaps just 20,000 years. The authors write, “A calcification crisis amongst hypercalcifying taxa is inferred for this period, with reefs and scleractinian corals experiencing a near-total collapse.” Again, though, it’s unclear how much of the catastrophe can be blamed on acidification rather than warming.
While our CO2 level won't go as high, it's moving much faster, and the rate of change is what drives acidification and the loss of carbonates needed by calcifying species.

Additional niceties, our current ocean chemistry is even more vulnerable to change:
The ratio of magnesium to calcium in ocean water changes over time due to differences in volcanic activity along the mid-ocean ridges, among other things. When magnesium is high (as it is today), a form of calcium carbonate called aragonite becomes dominant. Aragonite is more soluble than calcite, so “aragonite seas” are more susceptible to the effects of acidification. Even though the PETM did not feature aragonite seas, it was a tumultuous time for many marine species.
I haven't seen much discussion about how ocean acidification will affect climate, possibly because we have no idea.  Maybe it'll be wonderful!  I imagine tho that drastically changing the ocean biosphere is likely to have an effect, and because we're adjusted to the biosphere that we have, that effect is unlikely to be wonderful.

I'm sure that effect will be studied further.  Wiki links to a paywalled article about potential albedo decreases due loss of oceanic clouds, presumably from reduced nucleation particles from calcifying organisms getting into the atmosphere.  Wiki also speculates that acidification will help the ocean draw out more CO2 from the atmosphere.

David Archer sez calcifying plankton scatter light on their own, so their reduction can reduce albedo (Long Thaw, p. 118). OTOH I vaguely recall somewhere in his book he said that our killing off coral through acidification would leave more carbonate in solution, assisting the ocean's absorption of CO2.  I interpret that as part of the road to victory in the battle against Mother Earth, but others may differ.

I almost titled this post, "Time to panic over acidification" but tried to go with something slightly more constructive.  Time to get worried, at least.


David B. Benson said...

Oh, go ahead and have a panic attack.

OBothe said...

I recently attended a talk by Ulf Riebesell of IfM-Geomar (Kiel, Germany). He massively referred to this book and (among other things) discussed the uncertainties in which biogeochemical mechanism has which feedback effect on the climate. I guess, he wouldn't mind to give you a short summary of his thoughts to post here.

Hank Roberts said...

Time to get the petroleum geologists to open up their archives and share their work with the world?

Looks like the petrochemical reservoirs rely on pores in the sedimentary rock, opened up perhaps by methanogens in the sediment as it's subducted, and perhaps going on a long time.

Hm. Any hints that an ocean high in methanogens in the paleo record would be associated with climate change?

dbostrom said...

Come now, Richard Lindzen says we've no problem with C02 that we know of:

"The argument often is presented that the natural part is in balance and our contribution is imbalancing, unbalancing the system and so that’s leading to a rise. Uh, that’s an arguably possible situation but in point of fact there’s limited evidence of that and the merest uh misunderstanding of the 97% could easily overbalance man’s contribution but to be honest that is not an issue that is known at present and I would argue it’s not even the central issue."

See? C02 is "arguably possible" as a problem but we don't really know. Ocean acidification is probably due to other causes, such as us drinking too much wine.

Excellence and integrity will see us through these trying times. Fear not!

Anonymous said...

Elizabeth Kolbert's piece in the New Yorker (elitist pub though it be) is great:

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jcrabb said...

What does the current release of 1.3 tera tonnes of Methane from beneath the East Siberiab Sea do for CO2 levels?

I saw on the BBC site at the moment pepople are presenting this release as a 'planetary emergency' to UK MP's, 'bout time, in my humble opinion.

jcrabb said...

ad: considering that Methane is 75 times stronger GHP than CO2 in first 20 years and it is being released en masse at the moment, I don't see why the feedback effects, ie increased Volcanism due to accelerated Isostatic rebound (as documented in Greenland) can return us back to the good old days of high CO2 as just one truck stop on the road to hell.