Why is the ocean so important to Earths climate?
The ocean plays a key role in the climate system because it holds far more CO2 than the atmosphere or biosphere. Ocean waters absorb CO2 directly from the atmosphere, and some ocean organisms take up CO2 as they grow. Will climate change affect the ocean’s ability to remove CO2 from the atmosphere and thus intensify greenhouse warming? We do not know. How might changing conditions affect marine ecosystems? About 30 percent of the CO2 released by humans over the past 200 years has been absorbed by ocean waters. This has changed the chemistry of the water, making it less basic: the sea is “acidifying.” Ocean acidification could make it harder for shell-forming organisms, from corals to tiny plankton, to grow their shells. Eventually, shell-forming organisms could disappear.