The SCAR-OSC opened with a plenary by Professor Bob Bindschadler from Morgan State University and the Goddard Space Flight Centre, NASA. He gave a very entertaining lecture entitled, “What do ice sheets hate?”.
Ice sheets are shrinking faster and faster, but this change is heterogeneous with wide regional differences. There are three main different types of ice sheet change:
- Faster summer ice flow rates in outlet glaciers in Greenland;
- Rapidly disintegrating ice shelves around the Antarctic Peninsula;
- The rapid retreat, thinning and acceleration of outlet glaciers.
The cause of this change is WATER. In Greenland, enhanced surface melting results in large lake ponds, which find their way to the ice bed. This excess of water lubricates the bed, allowing faster seasonal rates of ice velocity, and increased ice discharge to the oceans. So, water is a LUBRICANT.
Around the Antarctic Peninsula, warm water is upwelling and melting ice shelves from below. During warm summer seasons, lots of meltwater forms ponds on the ice shelf, and melts downwards. These ponds cause ice shelf break up by hydrofracture. So, water is a WEDGE.
Finally, warm water is upwelling onto the continental shelf and melting ice shelves and ice sheets from the bottom up (see the recent Nature paper by Hamish Pritchard). Antarctica’s response and recession is currently mainly driven by this basal melting of ice shelves. So, water is a HEATER.
All of the major changes currently observed in Antarctica are, in one way or another, driven by water. And the Antarctic Ice Sheet has a large capacity for contributing to sea level rise.