"Glaciers Lose 204 Billion Tons of Ice in Three Years
"Antarctica is losing so much mass that it’s actually changing Earth’s gravity.
Antarctica is famously a continent capped with ice, but as Earth’s climate changes and the polar regions get warmer, its ancient ice is beginning to melt. The immediate consequence of the melting is the growing instability of ice shelves, places where the ice covering extends into the ocean. However, if we really want to know how quickly Antarctica is losing ice, we need a way of measuring that loss in terms of total mass.
"In that mission, scientists are aided by gravity. As Antarctic ice melts, it shifts mass from the continent into the oceans, slightly changing Earth’s gravitational field in that part of the world. We wouldn’t notice it, but orbiting observatories like the Gravity Field and Steady State Ocean Circulation Explorer (GOCE, which is more an abbreviation than acronym) can measure small fluctuations in gravity compared with other spots on our planet.
"Data from GOCE and the twin Gravity Recovery and Climate Experiment (GRACE) probes show that Antarctica is losing ice at a scary rate, as reported in
Geophysical Research Letters. Between 2009 and 2012, the years for which GOCE was taking data, the amount of gravity in Antarctica decreased noticeably, corresponding to a lot of ice melt.
"From the point of view of artificial satellites or the Moon, Earth’s gravity is mostly a steady influence, a tug that doesn’t particularly depend on where the satellite is over Earth’s surface. However, mass is the source of gravity, so if the crust is thicker in one place than another—say, the Himalayas vs. the floor of the Atlantic Ocean—the thicker part will exert a slightly higher gravitational pull."
http://www.thedailybeast.com/articl...e-204-billion-tons-of-ice-in-three-years.html
