Thanks to a rapid rebound in recent months, global sea ice
levels now equal those seen 29 years ago, when the year 1979
also drew to a close.
Ice levels had been tracking lower throughout much of 2008,
but rapidly recovered in the last quarter. In fact, the rate
of increase from September onward is the fastest rate of change
on record, either upwards or downwards.
The data is being reported by the University of Illinois's
Arctic Climate Research Center, and is derived from satellite
observations of the Northern and Southern hemisphere polar
regions.
Each year, millions of square kilometers of sea ice melt
and refreeze. However, the mean ice anomaly -- defined as
the seasonally-adjusted difference between the current value
and the average from 1979-2000, varies much more slowly. That
anomaly now stands at just under zero, a value identical to
one recorded at the end of 1979, the year satellite record-keeping
began.
