Climate change causes the ocean’s waters to expand

Contractors for the U.S. Army Corps of Engineers pump sand from the ocean floor onto the beach in the Rockaway Peninsula in New York City to craft a 250-foot-wide sandy beach along more than seven miles of shoreline to help protect the city from storms and rising sea levels. (AP Photo/Ted Shaffrey, File) Transcript: Melting ice is not the only reason global sea levels are rising. Climate change is also causing the ocean’s water to expand, pushing it farther onto shore. As the climate warms, most of the additional heat in the atmosphere is absorbed by the ocean. Today, the surface of the ocean is about 1.5 degrees Fahrenheit warmer than it was in the 1800s. When water gets hotter, water molecules start to move farther and farther away from each other. This causes the water to take up more space – a phenomenon called thermal expansion. This expansion is too small to notice in a cup or a bathtub – but across thousands of miles of ocean, it has a big impact. Over the past 30 years, global sea levels have risen by more than three inches. And scientists estimate that thermal expansion is likely responsible for about a third to a half of that increase. Sea level rise is already making floods more common in many coastal cities like Rockport, Texas, and Norfolk, Virginia. And as people add more planet-warming carbon pollution to the atmosphere, the ocean is warming and expanding, and glaciers are melting even faster. Together, these changes are causing sea levels to rise more rapidly and pushing the ocean farther onto shore. Reporting credit: Ethan Freedman / ChavoBart Digital Media