The reason the Arctic sea ice story is so important is ....

1. It's a key "canary in the coal mine". The amazing rapidity of change
in summer sea ice extent is an indicator of climactic changes globally.
With the rate of global greenhouse gas emission increases having gone up
sine the 1990s from an average of 1.1% p.a. to an average of 3.1% this
decade (now 3.4% according to a report I saw today) it's perhaps not
surprising that the whole thing is getting away from us.

2. The sea ice disappearance is one of the most significant tipping
points because of the loss of its albedo effect - a large slab of the
earth goes from being a heat reflector to a heat absorber. Not good.
It's also a harbinger of the mother of all tipping points - the thawing
of clathrates under the Arctic sea and the consequent vast release of
methane gas.

Check out these videos from a leading Arctic researcher that show what
methane gas seepage looks like:
http://www.alaska.edu/uaf/cem/ine/walter/videopage.xml. Sort of amusing
really, but methane gas is, of course, 20 times more potent a greenhouse
gas than carbon dioxide. Swedish scientists are already reporting an
increase in the ocean bubbling you see.

That means a lot more 40+ degree weeks in Australian summers, and a lot
more bushfire.

Sean