On 27/01/2017 16:36, John Hall wrote:
In message , N_Cook writes
I suppose when Larsen C breaks away, initially the sea-ice extent area
will show an increase, but area will be the same.

Ah. I've been wondering what the difference between "extent" and "area"
was, but I think that implicitly answers my question. So the "area" is
the total surface area of the frozen bits, while the "extent" is the
area that is at least partially frozen?

Extent includes leads and melt lakes.
It looks as though
sum [ concentration x extent (cell by cell)] = total area