© NASA
Increased water vapor in Earth's atmosphere due to human activities is making shimmering high-altitude clouds more visible, a new study finds. The results suggest these strange but increasingly common clouds seen only on summer nights are an indicator of human-caused climate change, according to the study's authors.
Comment: This is more likely due to warming coming from below: Global warming... in the deeps: Tremendous geothermal heat source is melting Antarctic ice sheet from below
Noctilucent, or night-shining, clouds are the highest clouds in Earth's atmosphere. They form in the middle atmosphere, or mesosphere, roughly 80 kilometers (50 miles) above Earth's surface. The clouds form when water vapor freezes around specks of dust from incoming meteors. Watch a video about noctilucent clouds here.
Comment: As well as the ever increasing fireball activity: Michigan Meteor Event: Fireball Numbers Increased Again in 2017
Humans first observed noctilucent clouds in 1885, after the eruption of Krakatoa volcano in Indonesia spewed massive amounts of water vapor in the air. Sightings of the clouds became more common during the 20th century, and in the 1990s scientists began to wonder whether climate change was making them more visible.
Comment: As noted in Rare high-elevation tornado forms near Weston Pass Fire, Colorado: Also check out SOTT radio's: