Learning From Our Oceans About Climate Change

The world’s oceans have a two-way relationship with the atmosphere. They influence the weather on a local and global scale, and atmospheric changes can fundamentally alter many oceanic properties. As carbon dioxide increases in our atmosphere, global temperatures rise. Melting polar ice leads to higher water levels and greater ocean temperatures, which in turn alter coastal and marine ecosystems. Warming sea temperatures can cause some fish species to move to cooler waters, which may reduce the ability of birds that nest in specific areas, such as puffins, to feed their chicks. At the same time, seawater absorbs carbon dioxide from the air, becoming more acidic.

Jane Lubchenco, former NOAA Aadministrator and Pew marine fellow, refers to ocean acidification as “climate change’s evil twin,” and for good reason: It’s a significant and harmful consequence of an increase in carbon dioxide. Over the past 200 years, ocean water has become 30 percent more acidic—a faster change in ocean chemistry than any known to have occurred during the previous 50 million years. More acidic seawater can hurt calcifying organisms such as oysters, clams, sea urchins, shallow water corals, deep-sea corals, and certain plankton.

Climate change and ocean acidification are affecting all the world’s oceans, including coastal estuaries and waterways. Many local economies depend on fish and shellfish, and coastal communities worldwide rely on seafood as a major source of protein. Pew-sponsored research helps delineate the impacts of climate change and develop approaches to manage them..