The Surf Check

UC Berkeley Lab oceanographers measure how oceans absorb carbon dioxide from the atmosphere. A recent study indicates the rate at which the ocean absorbs CO2 may be decreasing.

Courtesy Lawrence Berkeley National Laboratory @ flickr

Each year thousands of tons of carbon dioxide (CO2) are introduced into the atmosphere by natural and man-made processes. It is well documented that oceans are responsible for soaking up huge quantities of this carbon dioxide. Just like plants remove carbon from the atmosphere when they photosynthesize; oceans act as global carbon dioxide sponges.

Recently, new evidence has surfaced that shows the ocean’s natural mechanism to absorb carbon may be slowing. According to VOA News, Samar Khatiwala, of Columbia University, the lead author of a study, “found a growing imbalance between the amount of man-made carbon dioxide being pumped into the atmosphere and what the oceans, called carbon sinks, are able to handle.”

This is troubling for two reasons. First, as the world produces more carbon dioxide each year, as data suggests we do, the ocean may not be able to keep up with human output.

The other concern is when the decline will stop. When the ocean is saturated with CO2 it becomes acidic. According to National Geographic “more acidic waters are less able to dissolve carbon dioxide.” So, the ocean may not be able to absorb even the natural amount of carbon dioxide if it becomes overly acidic. This equates to an even larger carbon dioxide problem than we already face. The world has natural sponges to offset its own carbon dioxide, but it is possible that human output may even damage that capacity.

Current data by the Scrips Institute CO2 Program shows CO2 levels, which are related to ocean acidity, have steadily risen since the 1960′s.

Currently the ocean is one of the major depositories of carbon dioxide. The ocean currently stockpiles about 150 billion tons of CO2. Carbon dioxide that might otherwise be in the atmosphere. For example, in 2008 the oceans sucked up 2.3 billion tons of carbon. That is the equivalent of six years of U.S. gasoline consumption.

The map above depicts the amount of carbon taken out of the atmosphere by plant life. Along with the ocean itself, plant life also plays a major role in removing CO2 from the atmosphere.

Courtesy, NASA

In terms of numbers, last year the ocean absorbed 2.3 billion tons of carbon according to the study, the most ever. But, compared to the amount of man-made carbon dioxide the ocean’s absorption may have declined by as much as 10 percent, according to the study led by Samar Khatiwala, of Columbia University.

In a broad sense the ocean’s absorption of carbons dioxide directly relates to global warming. If less CO2 is absorbed by the ocean, it will remain in the atmosphere. Atmospheric CO2 is attributed to a warming trend in global temperatures. And unfortunately, carbon dioxide can’t dissolve as easily in warmer water. National geographic reports 40 percent of past carbon emissions are absorbed by frigid waters off the coast of Antarctica.

So, if the world’s oceans continue decline in carbon dioxide absorption, a downward spiral involving CO2 and a warming climate could potentially develop.