Older Arctic ice now shrinking

NEW Nasa satellite measurements show that sea ice in the Arctic is not just shrinking in area, but thinning dramatically.

The volume of older crucial sea ice in the Arctic has shrunk by 57% from late 2004 to 2008. That is losing more volume of ice than water in Lake Michigan.

Nasa scientist Jay Zwally blamed global warming and said rapidly shrinking sea ice in the Arctic warmed the rest of the globe indirectly.

Older ice is more important in the Arctic because it is thicker, surviving the heat of summer and building over time.