NASA’s website.) The loss of the Larsen B was a huge event, because it was the loss of a LOT of ice over a relatively short period of time.
|Satellite image of the Larsen B breakup from NASA's website|
Many of the scientists working from Rothera Station study the Larsen Ice Shelf. Some of them study why the Larsen B section broke off. (Scientists think it was caused by higher temperatures creating many pools of meltwater on the surface. The meltwater leaks into cracks and crevasses in the ice, to then act like wedges that deepen the cracks and break the ice into pieces.) The scientists I met study what that break-off means for the ice that remains. Is the remaining ice less stable now that it’s lost a huge chunk of itself? They have put GPS stations around the ice so that they can track the speed of its movement. It’s important to know if the rest of the Larsen Ice Shelf is stable, because its breaking would contribute to sea level rise.
I also met scientists who study what that loss of ice means for the rock and earth beneath the section that broke off. Ice is very heavy and can actually squash the rock and earth beneath it. We don’t usually think of rock and being squishy enough to be mashed down by ice, but the ice is that heavy! It can squash rock! When large pieces of ice disappear, the rock beneath it can re-expand now that the weight is no longer pushing it down. (Think about pushing down on a sponge with your hand. When you remove your hand, the sponge re-expands.) That happens pretty quickly after the ice is gone. Even after that re-expansion, the ground will continue expanding because the magma in the mantle is able to flow back in to the crust to keep pushing up on the earth. (Think again about pushing down on a sponge with your hand, but think about pushing it down in a bowl of water. When you move your hand, it would not only re-expand because the weight of your hand is gone, but it would also start to soak up water to expand even bigger.) Scientists are using radar and GPS to measure that ground expansion after the Larsen B fell off. Most of the expansion they’ve measured so far is actually from the mantle flowing back in, which surprised them, because they expected that part would happens much more slowly.
The Larsen B receives a lot of attention, but it was not the first or last of the ice shelves to break apart. There have been many other examples of major ice shelves breaking up over recent years, including the Wilkins Ice Shelf. Loss of ice is expected to continue of warming continues in this area.