Research by Daniel Kirk-Davidoff suggests that these structures, and not deep convective clouds, increased the temperature of the Earth during the Eocene Epoch by creating a positive feedback loop.
Research by Daniel Kirk-Davidoff suggests that these structures, and not deep convective clouds, increased the temperature of the Earth during the Eocene Epoch by creating a positive feedback loop. These objects are typically formed during an austral winter when wind passes over mountain ranges and subsequently induces the formation of gravity waves. That in turn leads to the creation of these structure's ice crystals which have temperatures lower than 85 degrees Celsius. Their one-A, one-B, and one-C types are composed of metastable water and nitric or sulphuric acid. They form at latitudes above 50 degrees and are usually only visible during twilight. These iridescent structures convert bromine and chlorine into forms that are highly reactive to ozone, suggesting that they play a role in global warming. For 10 points, name these polar clouds in the stratosphere that are named for their resemblance to mother of pearl. 
Research by Daniel Kirk-Davidoff suggests that these structures, and not deep convective clouds, increased the temperature of the Earth during the Eocene Epoch by creating a positive feedback loop.
nacreous clouds [accept  mother of pearl cloud before "mother" and accept  polar stratospheric cloud before polar.]