Thursday, March 20, 2008


Report on the World's Sea Ice

Over at The Cryosphere Today, the daily tally of the World's sea ice shows the following--in the North on the first day of Spring, the sea ice is just barely below normal and, in all 14 sub-areas, the sea ice is the same as, or above, where it was last year (5 are the same and 9 have more ice, some of them a lot more ice). The center of the Arctic Ocean, that is, the area inside 80 degrees latitude, is all frozen over and apparently much of the ice is thicker now than it was last Winter.
Although NASA reported two days ago it was thinner than usual. However their microwave measurement require new and not well tested modeling so take that with a grain of salt for the time being.

In the South, the sea ice is expanding in the Southern Autumn and is now more than a million square kilometers above normal. All told, the World's sea ice is just under a million square kilometers above normal. Last Southern Winter, there was more sea ice around Antarctica than ever and this Southern Summer less than usual melted (indeed, in only three Summers in the past 30 has the Antarctic sea ice melted more).

So we know that there is much more sea ice than normal, we also know from the state of the art Argo system that the sea itself has cooled recently, and we know in the past 15 months, no matter what measure you use, the World's mean temperature has gone down a full degree F.

No wonder the push is on to change the Warmie branding from Global Warming to Climate Change.

Another ice age is a climate change.

UPDATE: I've been thinking about Arctic sea ice thickness. Each year about ten to eleven million square kilometers melt completely away and three to five million square kilometers remains through the Summer. So most of the sea ice through the Winter will be what's called new ice, less than a year old, between one and two meters thick. Older ice, two to six years old, gets to be about 3 meters, and it is less salty and harder for reasons I don't fully understand. There are times the ice stacks up on top of other ice (mainly in pressure ridges) so the upper limit for thickness for sea ice is about 5 meters. But because of the absolutely normal yearly melt and refreeze cycle, most of the sea ice is new ice. This consensus information is not syncing up with the recent NASA story, which said that "perennial [older than one year old] ice used to cover 50-60 percent of the Arctic" If it generally melts from the normal 14.5 million square kilometers to the normal 4.5 million square kilometers every Summer, a loss of 70% (meaning 30% is left) how in the world could there be 60% multi year ice? There is something wrong here, if not with my math, perhaps with the definition of the term 'Arctic.' More later.


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