Like the vast forests of the world, which continually suck carbon dioxide from the atmosphere and release oxygen, the planet's oceans serve as vital carbon sinks. Last year the oceans absorbed as much as 2.3 billion tons of carbon, or about one-fourth of all manmade carbon emissions. Without the action of the oceans, the CO2 we emit into the atmosphere would have flame-broiled he planet by now.
But a new paper published by Samar Khatiwala in the Nov. 19 issue of Nature (see Nature editor's summary; full text requires subscription) demonstrates that the oceans' ability to absorb man-made carbon may be dwindling — and that has worrying ramifications for future climate change. While the ocean is now absorbing more carbon in total than ever before, the waters are sucking up a smaller percentage of the CO2 emitted by humans. That could mean that there's a physical limit to the oceans'capacity — and we could be hitting it. Full Article