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What did they do: For a new study, published in the journal Science On Thursday, an international research team determined the amount of carbon dioxide absorbed by the oceans.
What they found: The study shows that the oceans absorbed over 100 billion tonnes of CO2 between 1994 and 2007, about one-third of total emissions during this period.
- This shows that the oceans have roughly kept pace with the ever-increasing pace of man-made emissions during the period 1994-2007.
- Although the overall share of emissions absorbed by the oceans has not changed, the rate of carbon dioxide uptake by the oceans has increased four-fold between 1994 and 2007, compared to the period from 1800 to 1994, when revealed the study.
"Without this absorption by the oceans, the concentration of CO2 in the atmosphere would reach 480 ppm and global atmospheric temperatures would be considerably higher," said Axios, co-author of the study, Richard Feely.
"This means that the ocean provides humanity with an ecosystem service that can be valued at more than $ 1 trillion."
– The co-author of the study, Nicolas Gruber of ETH Zurich, tells Axios, assuming a carbon price of $ 10 per tonne of CO2.
Research also shows that ocean acidification, which results from chemical reactions when seawater absorbs CO2, begins to affect marine life well below the surface.
- Since the beginning of the industrial revolution, the pH of ocean surface waters has decreased by about 0.11 pH units, said Feely. The greatest decrease in pH is at high latitudes.
- Ocean acidification poses a major threat to calcifying organisms, such as butterflies and sea mussels, indicating that problems already exist in ecosystems.
Another study, published recently in Geology, provides a new long-term history of how carbon has accumulated in deep-sea sediments throughout the geology. Carbon is absorbed when dead diatoms and plankton descend into the water column, accumulating slowly but regularly as 'sea-ice' on the sea floor.
"The more acidic the ocean becomes, the more the number of dead plankton carbonated shells that sink into the water column is insufficient to get to the bottom of the sea without completely dissolving", explains to Axios, co-author of the study.
"In other words, we are constantly reducing the ability of the oceans to store atmospheric CO2 in deep-sea sediments."
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