The oceans are always in motion: wind and changes in seawater density drive massive ocean currents, transporting billions of tons of seawater around per second. These varying currents cause sea levels to differ from place to place, like stirring a cup of coffee. Sea level on the Pacific side of the Panama Canal, for example, is about a foot higher than on the Atlantic side. In a changing climate, wind patterns can shift, and enhanced evaporation of seawater and freshwater from local ice-melt makes the ocean fresher. Scientists call the regional shifts in such patterns “dynamic sea level change.” Over the last few decades as measured by satellite altimeters, dynamic sea-level changes have suppressed sea-level rise along the U.S. West Coast, and amplified sea-level rise along the U.S. East Coast. Whether these patterns will persist in the future is an active area of research.
