Jack Harrison wrote:

"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?

It could be a marker but only time will tell. The stratosphere may get
slightly cooler as the troposphere warms. It is complicated by the ozone
layer thinning. There have been a couple of papers about it fairly recently.

Perhaps more of interest to the UK weather watchers it might just
presage the appearance of nacreous clouds visible from the UK if we are
lucky. The ozone level over Uccle is dropping pretty rapidly so it is a
possibility. Please report any sightings (photos too if possible).

Regards,
Martin Brown