Polar ice clouds: Climate change symptom?

FAIRBANKS, Alaska, Aug. 22 (UPI) -- A U.S. study suggested that polar ice clouds -- wispy Arctic clouds that shine in the dark portion of the sky -- might be a symptom of climate change.

"The question which everyone in Alaska is dealing with is what are the symptoms of climate change and, as in medicine, how do these symptoms reflect the underlying processes," said Associate Professor Richard Collins of the University of Alaska-Fairbanks. "It is believed that (such clouds) are an indicator of climate change."

Noctilucent clouds form in the mesopause region, an area of the atmosphere 50 miles above Earth’s surface and the site of the lowest atmospheric temperatures. Collins said the ice clouds might serve as an indicator of climate change because an increase in carbon dioxide, which causes heating in the lower atmosphere, produces cooling in the upper atmosphere.

The clouds are a relatively new phenomenon, first reported during the 19th century and apparently becoming more prevalent since then.

Scientists from several countries were meeting this week at the university to discuss noctilucent clouds and other phenomena of the Earth’s upper atmosphere during the Eighth International Workshop on Layered Phenomena in the Mesopause Region.