Rare clouds over Antarctica

news.yahoo.com...

Resembling airborne mother-of-pearl shells, the clouds are produced when fading light at sunset passes through water-ice crystals blown along a strong jet of stratospheric air more than six miles above the ground.

Some say that these extreme temperatures are caused by global warming, and though I don't deny that global warming is real it seems to be a natural phase that the earth goes through, since there's evidence of it happening before.
Anyway I'm sure that those clouds would have been quite a sight.