Sunday, August 26, 2012

Goodbye, ice

There is likely to be a lot of (well deserved) publicity about the new Arctic sea ice extent minimum that will be reached in the next day or two.   In fact, according to some ways of counting the sea ice, we're already there.

People also need to remember that it has been a long time since the Arctic was ice free in summer;   according to a 2005 article, it may be 800,000 years ago, although I think I have seen suggestions to the contrary elsewhere.   It seems the Eemian period of global warmth about 125,000 still had winter sea ice in the Arctic, even while ocean levels were 3-7 m higher than today.   (While Googling, I stumbled across the question posed by the Institute for Creation Research - "Are Polar Ice Sheets Only 4500 Years Old?"  What was I worried about?)

But apart from the extent of Arctic ice, the volume of ice gives the better picture of what has been happening.  Tamino came up with this moving graph (click on it) some time ago, but he has reposted it.   It is pretty amazing.

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