In my reading, the wording was very confusing. Reading more carefully, it
seemed to me that they were saying that there will be less CO2 in the ocean
as a result of melting back of the sea ice. An open Arctic with no sea ice
formation would imply less down-welling due to not forming dense brine
pockets, so one mechanism would be a consequence of that, and another might
be due to the greater stability of the ocean in the warm season. I did not
read the paper, but, once I got past some unclear wording, the sign sort of
made sense.

Mike


On 9/23/14 1:52 PM, "Ken Caldeira" <[email protected]> wrote:

> Agree with Greg.
> 
> If there is any net effect of this process at all (relative to the no-ice
> situation) then quantitatively it must be tiny tiny tiny.
> 
> If the alkalinity represented by the Ca2+ in the CaCO3 was in the surface
> ocean with no ice, that would tend to draw CO2 into the ocean.
> 
> 
> _______________
> Ken Caldeira
> 
> Carnegie Institution for Science 
> Dept of Global Ecology
> 260 Panama Street, Stanford, CA 94305 USA
> +1 650 704 7212 [email protected]
> http://dge.stanford.edu/labs/caldeiralab  
> https://twitter.com/KenCaldeira
> 
> Assistant:  Dawn Ross <[email protected]>
> 
> 
> On Wed, Sep 24, 2014 at 5:45 AM, Rau, Greg <[email protected]> wrote:
>> "A new study has revealed that Arctic Sea ice helps remove carbon dioxide
>> from the atmosphere and its depletion would result in an increase of
>> atmospheric concentration of the gas." [?!]
>> 
>> How does removing CO2 from air increase air CO2 concentrations? Anyway, can
>> believe that CaCO3 precipitates and CO2 is generated as seawater freezes and
>> brine is formed: Ca(HCO3)2aq ---> CaCO3s + CO2g + H2O.  But whether the CO2
>> is then subducted with the sinking brine or degasses to the atmosphere would
>> seem critical to the air/ocean CO2 budget. That some CaCO3s is entrained in
>> the the ice seems logical, but how the preceding reaction is reversed to
>> consume this carbonate and CO2 is unclear. There would need to be a way
>> to concentrate CO2 to generate H2CO3 to then consume the CaCO3s to (re)make
>> Ca(HCO3)2aq.  How does that happen? Anyway, if it does happen this would seem
>> to offer a new explanation for glacial/ interglacial CO2 variations, not to
>> mention a new method of modern day CDR - bomb sea ice sheets with limestone
>> particles.  Beneficial "chemtrails on ice" ;-)
>> Greg
>>  
>> 
>> From: [email protected] [[email protected]] on
>> behalf of Andrew Lockley [[email protected]]
>> Sent: Tuesday, September 23, 2014 4:56 AM
>> To: geoengineering
>> Subject: [geo] Arctic sea ice depletion to result in rise of CO2 in
>> atmosphere | Zee News
>> 
>> http://zeenews.india.com/news/eco-news/arctic-sea-ice-depletion-to-result-in-
>> rise-of-co2-in-atmosphere_1474406.html
>> 
>> Arctic sea ice depletion to result in rise of CO2 in atmosphere Last Updated:
>> Tuesday, September 23, 2014 - 12:38
>> 
>> Washington: A new study has revealed that Arctic Sea ice helps remove carbon
>> dioxide from the atmosphere and its depletion would result in an increase of
>> atmospheric concentration of the gas.
>> 
>> Dorte Haubjerg Sogaard, PhD Fellow, Nordic Center for Earth Evolution,
>> University of Southern Denmark and the Greenland Institute of Natural
>> Resources, Nuuk, said that if their results are representative, then sea ice
>> plays a greater role than expected, and we should take this into account in
>> future global CO2 budgets.
>> 
>> The researchers said that they have long known that the Earth's oceans are
>> able to absorb huge amounts of CO2. But they also thought that this did not
>> apply to ocean areas covered by ice, because the ice was considered
>> impenetrable. However, this is not true, as the new research shows that sea
>> ice in the Arctic draws large amounts of CO2 from the atmosphere into the
>> ocean.
>> 
>> Sogaard said that the chemical removal of CO2 in sea ice occurs in two
>> phases. First crystals of calcium carbonate are formed in sea ice in winter.
>> During this formation CO2 splits off and is dissolved in a heavy cold brine,
>> which gets squeezed out of the ice and sinks into the deeper parts of the
>> ocean. Calcium carbonate cannot move as freely as CO2 and therefore it stays
>> in the sea ice. In summer, when the sea ice melts, calcium carbonate
>> dissolves, and CO2 is needed for this process. Thus, CO2 gets drawn from the
>> atmosphere into the ocean -and therefore CO2 gets removed from the
>> atmosphere.
>> 
>> ANI

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