An analysis of seawater samples from 24 sites revealed that the amount of CO2 absorbed into the water from 1999 to 2007 was half the level recorded from 1992 to 1999. Experts concluded that this decrease is being caused by warmer temperatures disrupting the process known as "ventilation" — the way seawater flows and mixes and drags absorbed CO2 from surface waters to the depths.
According to Kitack Lee of Pohang University of Science and Technology, working with Russia’s Pacific Oceanological Institute, this problem may be more widespread and could also affect CO2 uptake in the Southern and Atlantic oceans.
Currently the world’s oceans soak up about 11 billion tonnes of the human-produced CO2 – the main greenhouse gas blamed for global warming — each year, so even a slight weakening of the natural absorption process would leave significantly more CO2 in the atmosphere. An increase in CO2 would require stricter international emission targets if dangerous temperature rises are to be controlled.
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