[mewo2]

What that bit is referring to is that the ice shelf has been thinning as a result of climate change. The temperatures on the Antarctic Peninsula have increased by about 3˚C (5˚F) over the past half century or so, which is a huge change to the climate of a region.

[semi-extrinsic]

I get that the temperature increase is happening, but I don't get how this in turn increases the melting and thinning of ice. According to Wikipedia, summer temperatures in the warmest part of Antarctica still average below 0°C. Can someone explain?

[mewo2]

There's a big difference between average temperatures and peak temperatures. On Larsen C, we regularly measure localised temperatures in excess of 10˚C for days at a time. That's enough for some serious melt.

Also, surface melt is only half the story. The base of the ice is in contact with the ocean, which is also warming. Water in contact with ice is (more or less by definition) at the freezing/melting point - if it warms, the ice melts a bit, if it cools, the water freezes. So a change in ocean temperatures can have a big effect on melt rates.

Finally, it's not enough that the shelf be in equilibrium, melt-wise. The ice is constantly thinning, as it stretches and flows under its own weight. There needs to be enough extra mass added (mostly as snow) to compensate for that, if the shelf is to remain a constant thickness.

[semi-extrinsic]

Thank you! :)