"Jack Harrison" wrote in message
.. .

"Simon S" wrote
snip
European Commissioner for Science and Research Janez Potocnik.
....said
temperatures at a 20 kilometer (12 mile) height had dropped to
an average of minus 80 degrees Celsius the lowest over the Arctic in half
a century.

Question. Might this paradoxically be a sign of global warming?

My thinking is along the lines that the temperature in the stratosphere is
often LESS over tropical regions than it is in polar regions. This is
largely because the tropopause (the start of the stratosphere) in at a much
lower height over polar regions than it is at the equator.

What is really needed in order to make sense of that announcement is how the
height of the tropopause in the Artic compares now with what it has been
previously.

There was a paper in Science recently about changes in the height of the
tropopause. Here is a description of it.
http://www.llnl.gov/str/March04/Santer.html

I have not read it myself yet, so I do not know if it refers to the Arctic.

Cheers, Alastair.