Arctic Ocean - Not a Great CO2 Sink

The summer of 2010 has been agonizingly hot in much of the continental U.S., and the record-setting temperatures have refocused attention on global warming. Scientists have been looking at ways the Earth might benefit from natural processes to balance the rising heat, and one process had intrigued them, a premise that melting ice at the poles might allow more open water that could absorb carbon dioxide, one of the major compounds implicating in warming.

Now, though, in research just published in the journal Science and led by a University of Georgia marine chemist, that idea may be one more dead end. In fact, a survey of waters in the Canada Basin, which extends north of Alaska to the North Pole, shows that its value as a potential carbon dioxide “sink” may be short-lived at best and minor in terms of what the planet will need to avoid future problems.

What Cai and colleagues found was that as greater areas of ice melt each summer, the Canada Basin’s potential as a CO₂ sink will diminishdramatically mainly because of the rapid uptake of CO₂ from the atmosphere. And because of this carbon dioxide uptake, the waters become quite acidic and “a poor environment for calcium-carbonate shell-bearing marine organisms,” Cai said.

The findings are at once intriguing and disappointing because carbon dioxide and other gases dissolve more readily in cold water than warm water, and so scientists had long thought that seas of melting polar ice would at least have the trade-off of being good places for the absorption of carbon dioxide.