Satellites reveal rising seas

PlanetSave via Inside Science: New measurements from a pair of satellites nicknamed Tom and Jerry have provided a first time look into the planet’s average ocean level increase. Measuring gravity everywhere around the globe, Tom and Jerry have provided researchers with data showing that the annual world average sea level rise is about 1 millimetre.

Naturally, this is not a general 1 millimetre spread across the entire planet. In some areas such as the Pacific Ocean near the equator and the waters offshore from India and north of the Amazon river, the increase in sea level is larger; whereas in some areas such as off the east coast of the United States the sea levels have actually dropped.

Scientists, in an effort to get an accurate measurement of sea levels across the planet, have started measuring the gravity in any one place, determining how much mass lies in that region and whether it is the result of mountains, glaciers, mineral deposits or oceans. When the gravity changes, that refers to a loss of or increase in mass, which in the case of the oceans correlates to a rise or drop in ocean level.

…“GRACE is definitely the ‘real deal’ when it comes from measuring climate change from space,” said Joshua Willis, an ocean expert at the Jet Propulsion Laboratory in Pasadena, Calif. “This work by Dr. Riva and company reminds us that the world’s oceans don’t behave like a giant bathtub. As the ice melts and the water finds its way back to the ocean, the resulting sea level rise won’t be the same all over the world.”…

Artist's concept of Gravity Recovery and Climate Experiment