Monday, January 12, 2009

Surprise Drop In Carbon Dioxide Absorbed By East/Japan Sea

The East/Japan Sea in the western North Pacific is ventilated from the surface to the bottom of the ocean over decades. Such short overturning circulation indicates that carbon dioxide (CO2) from human emissions is able to pervade the East/Japan Sea on similarly short timescales.
Three surveys of the East/Japan Sea (conducted in 1992, 1999, and 2007, respectively) have allowed scientists to measure changes in the sea accumulation rate of CO2 emitted by humans in response to changes in surface conditions.
Park et al. analyze data from these surveys and find that the average uptake rate of anthropogenic CO2 by the East/Japan Sea from 1999 to 2007 was half of what it was for the period between 1992 and 1999.
Further, anthropogenic CO2 absorbed by the water more recently was confined to waters less than 300 meters (984 feet) in depth.
Because emissions have in fact accelerated over the past 10 years, the authors conclude that overturning circulation is weakening, slowing down the transport of anthropogenic CO2 from the surface to the interior of the East/Japan Sea.
Journal reference:
Geun-Ha Park et al. Sudden, considerable reduction in recent uptake of anthropogenic CO2 by the East/Japan Sea. Geophysical Research Letters, DOI: 10.1029/2008GL036118

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