Some of the glaciers are accelerating, and that has happened mostly in the last five, at most ten, years. There are significant changes going on. |
That record is getting long enough that it has pretty good accuracy. |
The melting of ice at the edges of the ice sheet is also increasing, which causes the ice to flow faster. A race is going on in Greenland between these competing forces of snow build-up in the interior and ice loss on the edges. But we don't know how long they will be approximately in balance with each other or if that balance has already tipped in favor of the recently accelerating outflow from glaciers. |
The study indicates that the contribution of the ice sheets to recent sea-level rise during the decade studied was much smaller than expected, just two percent of the recent increase of nearly three millimeters a year. Continuing research using NASA satellites and other data will narrow the uncertainties in this important issue. |
The warming ocean comes underneath the ice shelves and melts them from the bottom, and warmer air from the top melts them from the top. So they're thinning and eventually they get to a point where they go poof! |