New research has shown that ice free Arctic waters will not necessarily be a boon to carbon sequestration.
In what must be one of the best examples of looking for a silver lining in a storm cloud, scientists had been hoping that the unfortunate melting of Arctic ice would have opened up more of the ocean to become a carbon sink.
But research published in the journal Science has shown that those recently evacuated of their ice covering show little value as carbon sinks as their ability to hold carbon may be short lived at best.
“The Canada Basin and entire Arctic Ocean are still taking up carbon dioxide,” said Wei-Jun Cai, a professor in the department of marine biology in University of Georgia’s Franklin College of Arts and Sciences and lead author of the study. “But our research shows that as the ice melts, the carbon dioxide in the water very quickly reaches equilibrium with the atmosphere, so its use as a place to store CO2 declines dramatically and quickly. We never really understood how limited these waters would be in terms of their usefulness in soaking up carbon dioxide.”
With fears that the Arctic ocean might be ice free in 30 years abounding, researchers had predicted that the increased measure of open waters in the Arctic might have increased the amount of carbon stored within oceans.
“This prediction, however, was made based on observations of very low surface water carbon dioxide levels,” said Cai, “from either highly productive ocean margin areas or basin areas under earlier ice-covered conditions before the recent major ice retreat.”
Cai and colleagues aboard the Chinese research vessel Xue Long (Snow Dragon) took a three month voyage in 2008 to determine what was happening in the Canada Basin waters. What they found was that as greater areas of ice melt each summer, the Canada Basin’s potential as a carbon sink diminished dramatically, mainly because of the rapid uptake of carbon from the atmosphere. Because of this increased uptake, the waters became quite acidic and “a poor environment for calcium-carbonate shell-bearing marine organisms,” Cai said.
“One of the take-away lessons of this research is that we can’t expect the oceans to do the job of helping offset global warming in the short term,” said Cai.