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Images: How Long Can the Ocean Slow Global Warming?

In the chilly South Atlantic aboard the NOAA ship Ronald H. Brown, WHOI graduate student Naomi Levine and colleagues worked around the clock for weeks, taking samples of ocean water from many depths, to learn how much dissolved carbon dioxide has been absorbed by the sea, where it accumulates, and how much of the carbon in the ocean is human-generated. (Photo courtesy of Naomi Levine, Woods Hole Oceanographic Institution)

A graph of carbon dioxide levels in the atmosphere from the year 1000 to the present shows that CO2 has risen steadily since the 1800s due to human activities of fossil fuel burning and land use changes, and the upward trend is accelerating. The measurements are from two sources: air trapped inside ice cores, and direct measurements of the atmosphere (taken from the Hawaiian peak Mauna Loa) since the late 1950s. (Figure courtesy of Scott Doney, Woods Hole Oceanographic Institution)

As carbon dioxide builds up in the atmosphere, a large fraction has dissolved into the ocean, increasing the total amount of dissolved inorganic carbon and shifting seawater chemistry toward more acidic conditions. Since the end of the last century, the amount dissolved CO2 gas ([CO2 (aq)], shown as the red line) has increased because of both the rise in inorganic carbon levels and acidification. Simultaneously there is a decrease in the water?s pH (shown as the blue line), indicating rising acidity, and a decrease in the carbonate ion ([CO3 2- ], shown as the green line), the substance that many marine animals use to build their shells. (Figure courtesy of Scott Doney, Woods Hole Oceanographic Institution)

Organisms critical to ocean food webs, including plant-like coccolithophores (left), deep-sea corals (center), and small swimming snails called pteropods (right) depend on the ocean?s abundant dissolved inorganic carbonate for making their protective calcium carbonate shells. Declining carbonate and increasing acidity will likely make their shell formation difficult to impossible in large parts of the world ocean by the end of the 21st century, resulting in severe impacts on these organisms. (left photo by Richard D. Norris, Scripps Institution of Oceanography (formerly of WHOI); middle, courtesy NOAA; right, courtesy Laurence Madin, WHOI)

Color-coded maps of the ocean (in 2005 and projected in 2099) show areas where it is/will be easy for animals to make shells and skeletons (in colors of purple, red, orange, and yellow) and areas where making shells is/will be chemically difficult to impossible (dark and light blues). The maps are generated from current seawater measurements and projected values for the saturation state, a measure of solubility of calcium carbonate (aragonite). If projections hold, in much of the 2099 ocean, these animals, from plankton to corals, could be gone. (Figures courtesy Scott Doney, Woods Hole Oceanographic Institution)