Web edition: January 22, 2013
Scientists these days are worried about sea level. As Earth warms, the surface of the ocean is creeping upward. This creep is happening partly because saltwater expands a tiny bit as it warms. “Warmer water literally is taller,” explains Josh Willis. He’s a climate scientist at the NASA Jet Propulsion Laboratory in Pasadena, Calif.
He and others are learning how fast seas are rising, thanks in part to the Jason-2 satellite. Its eyes in the sky regularly measure the distance between its orbiting instruments and Earth’s surface. And the disturbing news: Seas are climbing quickly. In many areas, they threaten to seriously overrun coastal areas, especially during storms.