A NEW RECORD FOR ANTARCTIC ICE EXTENT?
While the news focus has been on the lowest ice extent since satellite monitoring began
in 1979 for the Arctic, the Southern Hemisphere (Antarctica) has quietly set a new record
for most ice extent since 1979.
This can be seen on the graphic below from the University of Illinois site (Chapman)
which is updated daily. The areal coverage is the highest in the satellite record (which
began in 1979), just beating out 1995, 2001, 2006 and 2007.
This winter has been an especially harsh one in the Southern Hemisphere with cold and
snow records set in Australia, South America and Africa. We will have recap on this
hard winter shortly.
Since 1979, the trend has been up over the satellite record for the total Antarctic ice
extent.
Though there was a flurry of media interest in 2002 when the Larsen Ice sheet broke up
and the ice extent declined rapidly, it was very temporary.
That break up which caused a big temporary decline in the southern ice extent was not
due to greenhouse warming but a big spike of solar activity, which caused significant
warming of low and middle latitudes, a shrinking or the polar vortices in both
hemispheres and actually even a temporary break-down for the first time ever of the
southern vortex. This caused an increase in the winds and currents leading to the ice
break-up. As the sun quieted, the ice quickly returned and has resumed its slow increase.
While the Antarctic Peninsula area has warmed in recent years and ice near it diminished
during the Southern Hemisphere summer, the interior of Antarctica has been colder and
ice elsewhere has been more extensive and longer lasting, which explains the increase in
total extent. This dichotomy was shown clearly in this blog posted recently by the World
Climate Report.
Note the average winter temperatures over the South Pole is about a degree colder than in
1957 and the coldest winter on record was 2004. This past winter was less cold with the
equivalent of what we call high latitude blocking in the northern hemisphere forcing cold
air to middle latitudes. This explains the cold extremes in Australia, South America and
Africa.
The Southern and Northern Hemisphere have been out of sync, with little warming noted
in the oceans or land in the Southern Hemisphere during the recent warming period in the
Northern Hemisphere.