What is the ocean’s role in Earth’s climate? Earth is often called the blue planet because the Atlantic, Pacific, Indian, Arctic and Southern oceans cover 71 percent of it. Just the Pacific alone covers more than half the planet, and more than all the land areas combined. Oceans contain nearly 1.34 billion km3 of water, and Earth’s waters are overwhelmingly salt water—97 percent—plus 2 percent ice and 1 percent fresh water. The ocean is our planet’s largest heat sink. By absorbing, storing and then slowly releasing large quantities of heat, the ocean buffers the climate of the nearby land and, over time, the entire planet.
Are sea levels rising?
When water warms, it expands and takes up more volume. This effect is called “thermal expansion.” Long-term measurements demonstrate that sea levels are rising worldwide both from thermal expansion caused by warming temperatures and from the addition of water from inland glaciers, which are melting nearly everywhere at accelerating rates. Increased melting is also occuring at the ice caps in Greenland and West Antarctica.
Many scientists now think that sea levels will rise by at least one to two feet by 2100. A rise of two to six feet is possible, if emissions of greenhouse gases remain unchecked and significant melting of the ice caps occurs. A rise in sea level of just a foot or two could have significant negative consequences for islands in the Caribbean and the Pacific and for low-lying coastal areas along the continental U.S., such as the eastern shoreline of Cape Cod, the barrier islands protecting North Carolina, most of southern Florida and the city of Boston. Since most of the world’s major cities also lie along ocean coastlines, sea level rise has major implications for those important population centers, where erosion, flooding and rising groundwater levels will threaten buildings, roads, subway systems and other essential services.
*info provided by the new england aquarium