It's puzzling why Antarctic sea ice seems to be
growing while earth's other icy expanses are shrinking as
Now new research questions whether there has been much
of a rise in Antarctic sea ice after all. The paper suggests the
small but significant growth scientists thought had occurred since
1979 could be little more than a "spurious artifact" of how
satellite data is interpreted.
But other polar scientists tell us the implications of
the new findings" are very limited indeed" and they're confident
Antarctic sea ice is still growing.
Bucking the trend
Scientists know ice is being lost from both the
Greenland and Antarctic ice
sheets. They also know the amount of sea ice in the Arctic is
But satellite data suggest the amount of sea ice
has been growing since 1979. A report from the
Intergovernmental Panel on Climate Change (IPCC) last year put the
size of the increase at
1.5 per cent on average per decade.
For comparison, that's about a third of the rate of
sea ice retreat in the Arctic. A
new paper just published in journal The Cryosphere
explains the puzzle this poses for scientists:
"[T]here has been substantial
interest in the trend in Antarctic sea ice extent … primarily
because of the observed asymmetry between increasing ice extent in
the Antarctic and rapidly diminishing ice extent in the Arctic, and
the inability of current climate models to capture this."
The new paper raises an interesting point. It notes
that the growth in Antarctic sea ice in the latest IPCC report is
much bigger than suggested in the previous one in 2007. The authors
"[The 2007 report] reported
the trend in Antarctic sea ice extent to be small and statistically
indistinguishable from zero".