Scientists Suspect These Rare Clouds Could be Another Sign of Climate Change

Noctilucent clouds are a mysterious marvel of the night sky. The beautiful blue ice clouds are a rare sight to behold, but are they pointing to something sinister in the atmosphere?

According to NASA, the blue clouds were first spotted in 1885 after the eruption of volcano Krakatoa sent tons of volcanic ash high into the atmosphere. Since then, the clouds that form high in the atmosphere (nearly 50 miles above Earth’s surface) are a sight traditionally reserved for summer nights in far north regions like Russia and Scandinavia.

They are only visible a few weeks out of the year when atmospheric conditions are perfect. “Noctilucent season” generally falls between the beginning of June and the end of July. 

But according to USA Today, the formations are now appearing in southern regions such as Utah, Colorado and Virginia. So why are they appearing so far south? Some scientists say it's a sign that noctilucent clouds could be linked to climate change. Produced in the mesosphere or upper atmosphere where clouds generally struggle to form, scientists think that greenhouse gases may be aiding in the creation of the noctilucent clouds.

While greenhouse gasses generally warm the atmosphere, they serve as a cooling agent when they reach the mesosphere which could play a significant role in making more of the icy clouds. This is only one theory and as atmospheric researcher Tony Phillips tells SF Gate, “the jury is still out.”

http://www.weather.com/science/environment/news/climate-change-noctilucent-clouds-theory