The ocean plays a central—yet underappreciated—role in global climate and regional weather patterns, including droughts, rainstorms, and hurricanes. Through its food webs and chemical reactions, the ocean helps to regulate Earth's climate by taking up carbon dioxide from the atmosphere and moving a fraction of that carbon through the ocean twilight zone to the deep ocean, where it can remain sequestered out of the atmosphere for hundreds or even thousands of years. The ocean also absorbs heat: ocean waters have absorbed most of human-caused global warming.
The ocean also plays an important role in regional weather patterns. The saltiness of surface water in one part of the ocean has been linked to rainfall patterns on land thousands of miles away. Surface water temperature can help predict the intensity of storms—something scientists have learned by launching temperature probes from military aircraft into the path of a hurricanes.
In turn, a warming global climate is affecting the ocean in significant ways, through shifts in major currents, sea level rise, and changes in water temperature, pH, salinity, and productivity. Climate change is visible in Greenland's receding ice sheet and declines in Antarctic wildlife, but also in the "super corals" that have found the means to survive in a warming ocean. The ocean preserves records of past changes in climate and weather—in its sediments, in coral skeletons, and even in whaling log books—just as present-day commercial fishers bear witness to ocean warming and its impacts on fisheries.
Using sophisticated computer models, satellite remote sensing, and long-term datasets, scientists can analyze interactions between the ocean and the atmosphere to better understand climate and weather patterns on a variety of timescales. Climate change is the environmental crisis of our time, and understanding the ocean's role in climate is essential to mitigating its impacts—for our ocean, our planet, and our future.