| Austin
said the surface
temperature increase
is not only "a
symptom of climate
change," but also
could reinforce
itself. A trend toward
warmer winters would
mean less winter ice
cover, which would
allow more solar
radiation of the lake
and continued warming,
he said.
Lake
Superior freezes over
completely about once
every 20 years,
according to the
Minnesota DNR's
climatology office. If
trends continue, it
could be routinely
ice-free by about
2040, the study found.
This would cause water
levels to continue to
drop because the lake
loses more water to
evaporation in a
winter without ice
cover than it does
during the summer. In
recent months, the
lake's level has been
lower than at any
equivalent time since
1926.
The
study was first
published by the
American Geophysical
Union on March 23.
|
