The icefloe which covers the arctic ocean in summer and in winter differs in expanse and thickness according to places and
seasons. It develops when sea water temperature drops under -1,8°C. The average thickness is 2,5 m , it is
composed of perennal ice and first year ice. However it can be 5 m thick or more in the compression
crests where it can reach 10 m high and go down 30 m under the surface.

Icefloe, icecap and icebergs

We should not mix up icefloe which is an icy ocean with icecap of Greenland or Antarctic which are made of soft water ice, nor with icebergs which are pieces of glaciers that have separated on reaching the coast. However, just like them, icefloe floats on the ocean, the ice being less dense than water.

The icefloe drift

Yet to come…

The icefloe : a macrocosm endangered

Because of global warming,the icefloe could definitely disappear in summer in a matter of 8 to 15 years (source : CNRS/ IFREMER). Of course, it will reform each winter thanks to polar night but it will never be the same : its’ thickness will stay a yearly ice. We will be able to observe it only by night or with dim light and reliefs will also be reduced…

To know more, see the link A threatened environment

Why is the icefloe melting so fast ?

The icefloe has entered an accelerating process of melting in the last years. This phenomenon is due to diminishing of the white areas which used to better reflect the sunshine before (albedo). The dark of the open water area absorbs 75% of the sunshine (15% for a snowy surface) thus increasing the warming by proximity. Moreover the warming of oceanic water, air streams and acceleration of the icefloe drift make the melting worse.